Intraoperative Assessment of Fluid Responsiveness in Normotensive Dogs under Isoflurane Anaesthesia.
Skouropoulou Despoina,Lacitignola Luca,Di Bella Caterina,Stabile Marzia,Acquafredda Claudia,Brienza Nicola,Grasso Salvatore,Crovace Antonio,Iarussi Fabrizio,Staffieri Francesco
The aim of this study was to evaluate the incidence of fluid responsiveness (FR) to a fluid challenge (FC) in normotensive dogs under anaesthesia. The accuracy of pulse pressure variation (PPV), systolic pressure variation (SPV), stroke volume variation (SVV), and plethysmographic variability index (PVI) for predicting FR was also evaluated. Dogs were anaesthetised with methadone, propofol, and inhaled isoflurane in oxygen, under volume-controlled mechanical ventilation. FC was performed by the administration of 5 mL/kg of Ringer's lactate within 5 min. Cardiac index (CI; L/min/m), PPV, (%), SVV (%), SPV (%), and PVI (%) were registered before and after FC. Data were analysed with ANOVA and ROC tests ( < 0.05). Fluid responsiveness was defined as 15% increase in CI. Eighty dogs completed the study. Fifty (62.5%) were responders and 30 (37.5%) were nonresponders. The PPV, PVI, SPV, and SVV cut-off values (AUC, ) for discriminating responders from nonresponders were PPV >13.8% (0.979, <0.001), PVI >14% (0.956, <0.001), SPV >4.1% (0.793, <0.001), and SVV >14.7% (0.729, <0.001), respectively. Up to 62.5% of normotensive dogs under inhalant anaesthesia may be fluid responders. PPV and PVI have better diagnostic accuracy to predict FR, compared to SPV and SVV.
Dynamic arterial elastance obtained using arterial signal does not predict an increase in arterial pressure after a volume expansion in the operating room.
Lanchon Romain,Nouette-Gaulain Karine,Stecken Laurent,Sesay Musa,Lefrant Jean-Yves,Biais Matthieu
Anaesthesia, critical care & pain medicine
INTRODUCTION:Dynamic arterial elastance (Eadyn) is defined as the ratio between pulse pressure variations (PPV) and stroke volume variations (SVV). Eadyn has been proposed to predict an increase in mean arterial pressure (MAP) after volume expansion with conflicting results. The aim of the present study was to test the reliability of Eadyn in hypotensive patients (MAP<65mmHg) in the operating room (OR). PATIENTS AND METHODS:The study pooled data from 51 patients. They were included after the induction of anaesthesia and before skin incision. Eadyn, MAP and stroke volume (FloTrac™, Vigileo™, Edwards Lifesciences, Irvine,CA) were recorded before and after volume expansion (500mL starch 6% given over 10minutes). Pressure-responders were defined as an increase MAP≥15% after volume expansion. Changes in MAP were predicted using the area under the curves (AUC) with their 95% Confidence Interval (95%CI) derived from Receiver Operating Characteristic curves. RESULTS:Seventeen patients responded to volume expansion. Heart rate, PPV, SVV and Eadyn were similar between pressure-responders and non-responders. Baseline values of stroke volume, cardiac output and MAP were lower in responders. Volume expansion induced significant variations in stroke volume, cardiac output, SVV and PPV, but not in Eadyn. Baseline Eadyn failed to predict MAP increase (AUC=0.53, 95%CI=0.36-0.70, P>0.05) and was not correlated with volume expansion-induced changes in MAP (P>0.05). In preload responsive patients (changes in SV≥15% after volume expansion, n=24), the AUC was 0.54 (95%CI=0.29-0.78; P>0.05). CONCLUSION:In the present study performed in the OR and in hypotensive patients, Eadyn obtained using arterial signal was unable to predict an increase in MAP after volume expansion.
A systematic review of pulse pressure variation and stroke volume variation to predict fluid responsiveness during cardiac and thoracic surgery.
Piccioni Federico,Bernasconi Filippo,Tramontano Giulia T A,Langer Martin
Journal of clinical monitoring and computing
This systematic review aims to summarize the published data on the reliability of pulse pressure variation (PPV) and stroke volume variation (SVV) to predict fluid responsiveness in an open-chest setting during cardio-thoracic surgery. The analysis included studies reporting receiver operating characteristics or correlation coefficients between PPV/SVV and change in any hemodynamic variables after a fluid challenge test in open-chest conditions. The literature search included seven studies. Increase in cardiac index and stroke volume index after a fluid challenge were the most adopted end-point variables. PPV and SVV showed similar area under the receiver operating characteristic curve values but high heterogeneity among studies. Cardiac and thoracic studies did not differ between PPV/SVV pooled area under the receiver operating characteristic curve. Studies exploring correlation between dynamic indices and end-point variable increase after fluid challenge showed conflicting results. The great heterogeneity between studies was due to small sample size and differences among protocol designs (different monitor devices, mechanical ventilation settings, fluid challenge methodologies, surgical incisions, and end-point variables). PPV and SVV seem to be inaccurate in predicting fluid responsiveness in an open-chest setting during cardio-thoracic surgery. Given the high heterogeneity of published data, more studies are needed to define the role of PPV/SVV in this context.
Incorporating Dynamic Assessment of Fluid Responsiveness Into Goal-Directed Therapy: A Systematic Review and Meta-Analysis.
Bednarczyk Joseph M,Fridfinnson Jason A,Kumar Anand,Blanchard Laurie,Rabbani Rasheda,Bell Dean,Funk Duane,Turgeon Alexis F,Abou-Setta Ahmed M,Zarychanski Ryan
Critical care medicine
OBJECTIVE:Dynamic tests of fluid responsiveness have been developed and investigated in clinical trials of goal-directed therapy. The impact of this approach on clinically relevant outcomes is unknown. We performed a systematic review and meta-analysis to evaluate whether fluid therapy guided by dynamic assessment of fluid responsiveness compared with standard care improves clinically relevant outcomes in adults admitted to the ICU. DATA SOURCES:Randomized controlled trials from MEDLINE, EMBASE, CENTRAL, clinicaltrials.gov, and the International Clinical Trials Registry Platform from inception to December 2016, conference proceedings, and reference lists of relevant articles. STUDY SELECTION:Two reviewers independently identified randomized controlled trials comparing dynamic assessment of fluid responsiveness with standard care for acute volume resuscitation in adults admitted to the ICU. DATA EXTRACTION:Two reviewers independently abstracted trial-level data including population characteristics, interventions, clinical outcomes, and source of funding. Our primary outcome was mortality at longest duration of follow-up. Our secondary outcomes were ICU and hospital length of stay, duration of mechanical ventilation, and frequency of renal complications. The internal validity of trials was assessed in duplicate using the Cochrane Collaboration's Risk of Bias tool. DATA SYNTHESIS:We included 13 trials enrolling 1,652 patients. Methods used to assess fluid responsiveness included stroke volume variation (nine trials), pulse pressure variation (one trial), and stroke volume change with passive leg raise/fluid challenge (three trials). In 12 trials reporting mortality, the risk ratio for death associated with dynamic assessment of fluid responsiveness was 0.59 (95% CI, 0.42-0.83; I = 0%; n = 1,586). The absolute risk reduction in mortality associated with dynamic assessment of fluid responsiveness was -2.9% (95% CI, -5.6% to -0.2%). Dynamic assessment of fluid responsiveness was associated with reduced duration of ICU length of stay (weighted mean difference, -1.16 d [95% CI, -1.97 to -0.36]; I = 74%; n = 394, six trials) and mechanical ventilation (weighted mean difference, -2.98 hr [95% CI, -5.08 to -0.89]; I = 34%; n = 334, five trials). Three trials were adjudicated at unclear risk of bias; the remaining trials were at high risk of bias. CONCLUSIONS:In adult patients admitted to intensive care who required acute volume resuscitation, goal-directed therapy guided by assessment of fluid responsiveness appears to be associated with reduced mortality, ICU length of stay, and duration of mechanical ventilation. High-quality clinical trials in both medical and surgical ICU populations are warranted to inform routine care.
Functional hemodynamic tests: a systematic review and a metanalysis on the reliability of the end-expiratory occlusion test and of the mini-fluid challenge in predicting fluid responsiveness.
Messina Antonio,Dell'Anna Antonio,Baggiani Marta,Torrini Flavia,Maresca Gian Marco,Bennett Victoria,Saderi Laura,Sotgiu Giovanni,Antonelli Massimo,Cecconi Maurizio
Critical care (London, England)
BACKGROUND:Bedside functional hemodynamic assessment has gained in popularity in the last years to overcome the limitations of static or dynamic indexes in predicting fluid responsiveness. The aim of this systematic review and metanalysis of studies is to investigate the reliability of the functional hemodynamic tests (FHTs) used to assess fluid responsiveness in adult patients in the intensive care unit (ICU) and operating room (OR). METHODS:MEDLINE, EMBASE, and Cochrane databases were screened for relevant articles using a FHT, with the exception of the passive leg raising. The QUADAS-2 scale was used to assess the risk of bias of the included studies. In-between study heterogeneity was assessed through the I indicator. Bias assessment graphs were plotted, and Egger's regression analysis was used to evaluate the publication bias. The metanalysis determined the pooled area under the receiving operating characteristic (ROC) curve, sensitivity, specificity, and threshold for two FHTs: the end-expiratory occlusion test (EEOT) and the mini-fluid challenge (FC). RESULTS:After text selection, 21 studies met the inclusion criteria, 7 performed in the OR, and 14 in the ICU between 2005 and 2018. The search included 805 patients and 870 FCs with a median (IQR) of 39 (25-50) patients and 41 (30-52) FCs per study. The median fluid responsiveness was 54% (45-59). Ten studies (47.6%) adopted a gray zone analysis of the ROC curve, and a median (IQR) of 20% (15-51) of the enrolled patients was included in the gray zone. The pooled area under the ROC curve for the end-expiratory occlusion test (EEOT) was 0.96 (95%CI 0.92-1.00). The pooled sensitivity and specificity were 0.86 (95%CI 0.74-0.94) and 0.91 (95%CI 0.85-0.95), respectively, with a best threshold of 5% (4.0-8.0%). The pooled area under the ROC curve for the mini-FC was 0.91 (95%CI 0.85-0.97). The pooled sensitivity and specificity were 0.82 (95%CI 0.76-0.88) and 0.83 (95%CI 0.77-0.89), respectively, with a best threshold of 5% (3.0-7.0%). CONCLUSIONS:The EEOT and the mini-FC reliably predict fluid responsiveness in the ICU and OR. Other FHTs have been tested insofar in heterogeneous clinical settings and, despite promising results, warrant further investigations.
Fluid Challenge During Anesthesia: A Systematic Review and Meta-analysis.
Messina Antonio,Pelaia Corrado,Bruni Andrea,Garofalo Eugenio,Bonicolini Eleonora,Longhini Federico,Dellara Erica,Saderi Laura,Romagnoli Stefano,Sotgiu Giovanni,Cecconi Maurizio,Navalesi Paolo
Anesthesia and analgesia
BACKGROUND:Assessing the volemic status of patients undergoing surgery is part of the routine management for the anesthesiologist. This assessment is commonly performed by means of dynamic indexes based on the cardiopulmonary interaction during mechanical ventilation (if available) or by administering a fluid challenge (FC). The FC is used during surgery to optimize predefined hemodynamic targets, the so-called Goal-Directed Therapy (GDT), or to correct hemodynamic instability (non-GDT). METHODS:In this systematic review, we considered the FC components in studies adopting either GDT or non-GDT, to assess whether differences exist between the 2 approaches. In addition, we performed a meta-analysis to ascertain the effectiveness of dynamic indexes pulse pressure variation (PPV) and stroke volume (SV) variation (SVV), in predicting fluid responsiveness. RESULTS:Thirty-five non-GDT and 33 GDT studies met inclusion criteria, including 5017 patients. In the vast majority of non-GDT and GDT studies, the FC consisted in the administration of colloids (85.7% and 90.9%, respectively). In 29 non-GDT studies, the colloid infused was the 6% hydroxyethyl starch (6% HES; 96.6% of this subgroup). In 20 GDT studies, the colloid infused was the 6% HES (66.7% of this subgroup), while in 5 studies was a gelatin (16.7% of this subgroup), in 3 studies an unspecified colloid (10.0% of this subgroup), and in 1 study albumin (3.3%) or, in another study, both HES 6% and gelatin (3.3%). In non-GDT studies, the median volume infused was 500 mL; the time of infusion and hemodynamic target to assess fluid responsiveness lacked standardization. In GDT studies, FC usually consisted in the administration of 250 mL of colloids (48.8%) in 10 minutes (45.4%) targeting an SV increase >10% (57.5%). Only in 60.6% of GDT studies, a safety limit was adopted. PPV pooled area under the curve (95% confidence interval [CI]) was 0.86 (0.80-0.92). The mean (standard deviation) PPV threshold predicting fluid responsiveness was 10.5% (3.2) (range, 8%-15%), while the pooled (95% CI) sensitivity and specificity were 0.80 (0.74-0.85) and 0.83 (0.73-0.91), respectively. SVV pooled area under the curve (95% CI) was 0.87 (0.81-0.93). The mean (standard deviation) SVV threshold predicting fluid responsiveness was 11.3% (3.1) (range, 7.5%-15.5%), while the pooled (95% CI) sensitivity and specificity were 0.82 (0.75-0.89) and 0.77 (0.71-0.82), respectively. CONCLUSIONS:The key components of FC including type of fluid (colloids, often 6% HES), volume (500 and 250 mL in non-GDT studies and GDT studies, respectively), and time of infusion (10 minutes) are quite standardized in operating room. However, pooled sensitivity and specificity of both PPV and SVV are limited.
Assessment of Fluid Responsiveness in Prone Neurosurgical Patients Undergoing Protective Ventilation: Role of Dynamic Indices, Tidal Volume Challenge, and End-Expiratory Occlusion Test.
Messina Antonio,Montagnini Claudia,Cammarota Gianmaria,Giuliani Fabiana,Muratore Lara,Baggiani Marta,Bennett Victoria,Della Corte Francesco,Navalesi Paolo,Cecconi Maurizio
Anesthesia and analgesia
BACKGROUND:In patients in the prone position, the reliability of pulse pressure variation and stroke volume variation (PPV and SVV) and the use of functional hemodynamic tests to predict fluid responsiveness have not previously been established. Perioperatively, in this setting, optimizing fluid management can be challenging, and fluid overload is associated with both intraoperative and postoperative complications. We designed this study to assess the sensitivity and specificity of baseline PPV and SVV, the tidal volume (VT) challenge (VTC) and the end-expiratory occlusion test (EEOT) in predicting fluid responsiveness during elective spinal surgery. METHODS:The study protocol was started during a period of intraoperative hemodynamic stability after prone positioning and before the administration of any vasopressor: (1) at baseline, the controlled ventilation was set at 6 mL/kg of predicted body weight (PBW) (T0); (2) patients underwent the first EEOT (EEOT6) by interrupting the mechanical ventilation for 30 seconds; (3) the ventilation was set again at 6 mL/kg PBW for 1 minute (T1); (4) the VTC was applied by increasing the VT up to 8 mL/kg PBW for 1 minute; (5) the ventilation was kept at 8 mL/kg PBW for 1 minute (T2); (6) a second EEOT (EEOT8) was performed; (7) the VT was reduced back to 6 mL/kg PBW for 1 minute (T3); (8) a fluid challenge of 250 mL of Ringer's solution was infused over 10 minutes. After each step, a complete set of hemodynamic measurements was recorded. RESULTS:Neither PPV and SVV values recorded at T3 nor the EEOT6 or the EEOT8 predicted fluid responsiveness. The change in PPV after VTC application predicted fluid responsiveness with an area under the curve of 0.96 (95% confidence interval, 0.87-1.00), showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 12.2%. The change in SVV after VTC application predicted fluid responsiveness with an area under the curve 0.96 (95% confidence interval, 0.89-1.00) showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 8.0%. A linear correlation between stroke volume index changes after fluid challenge administration and the changes in PPV and SVV after VTC application was observed (r = 0.71; P < .0001 and r = 0.68; P < .0001, respectively). CONCLUSIONS:In prone elective neurosurgical patients, the baseline values of PPV and SVV and the EEOT fail to predict fluid responsiveness, while the VTC is a very reliable functional hemodynamic test and could be helpful in guiding intraoperative fluid therapy.
Ability of Carotid Corrected Flow Time to Predict Fluid Responsiveness in Patients Mechanically Ventilated Using Low Tidal Volume after Surgery.
Jung Seungho,Kim Jeongmin,Na Sungwon,Nam Won Seok,Kim Do-Hyeong
Journal of clinical medicine
Predicting fluid responsiveness in patients under mechanical ventilation with low tidal volume (VT) is challenging. This study evaluated the ability of carotid corrected flow time (FTc) assessed by ultrasound for predicting the fluid responsiveness during low VT ventilation. Patients under postoperative mechanical ventilation and clinically diagnosed with hypovolemia were enrolled. Carotid FTc and pulse pressure variation (PPV) were measured at VT of 6 and 10 mL/kg predicted body weight (PBW). FTc was calculated using both Bazett's (FTcB) and Wodey's (FTcW) formulas. Fluid responsiveness was defined as a ≥15% increase in the stroke volume index assessed by FloTrac/Vigileo monitor after administration of 8 mL/kg of balanced crystalloid. Among 36 patients, 16 (44.4%) were fluid responders. The areas under the receiver operating characteristic curves (AUROCs) for the FTcB at VT of 6 and 10 mL/kg PBW were 0.897 (95% confidence interval [95% CI]: 0.750-0.973) and 0.895 (95% CI: 0.748-0.972), respectively. The AUROCs for the FTcW at VT of 6 and 10 mL/kg PBW were 0.875 (95% CI: 0.722-0.961) and 0.891 (95% CI: 0.744-0.970), respectively. However, PPV at VT of 6 mL/kg PBW (AUROC: 0.714, 95% CI: 0.539-0.852) showed significantly lower accuracy than that of PPV at VT of 10 mL/kg PBW (AUROC: 0.867, 95% CI: 0.712-0.957; = 0.034). Carotid FTc can predict fluid responsiveness better than PPV during low VT ventilation. However, further studies using automated continuous monitoring system are needed before its clinical use.
Effects of stroke volume variation, pulse pressure variation, and pleth variability index in predicting fluid responsiveness during different positive end expiratory pressure in prone position.
Chen Yu,Fu Qiang,Mi Wei-dong
Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae
OBJECTIVE:To investigate the effects of different positive end expiratory pressures (PEEP) on functional hemodynamic parameters in patients lying in prone position during operation under general anesthesia. METHODS:Totally 60 patients undergoing cervical vertebra operation or lumbar vertebra operation were studied. All patients were also monitored with Vigileo／FloTrac system. The functional hemodynamic parameters including stroke volume variation (SVV), pulse pressure variation (PPV), and pleth variability index (PVI) under PEEP levels of 0 mmHg, 5 mmHg, 10 mmHg, and 15 mmHg were recorded before and after volume expansion (hydroxyethyl starch 6%,7 ml/kg). Fluid responsiveness was defined as an increase in stroke volume index (SVI) ≥ 15%(△SVI ≥ 15%). Responders were defined as patients demonstrating an increase in SVI ≥ 15% after intravascular volume expansion and non-responders as patients whose SVI changed <15%. Receiver operating characteristic (ROC) curves were generated for SVV, PPV, and PVI under different PEEP levels to determine their diagnosis accuracies and thresholds and their potential correlations. RESULTS:In the prone position, SVV, PPV, and PVI were significantly higher compared to those in the supine position (P<0.05) and the mean arterial pressure significantly decreased (P<0.05); however, the changes of heart rate, stroke volume, SVI, cardiac output, and cardiac index showed no significant difference (P>0.05). In the prone position, along with the elevation of PEEP (0 mmHg, 5 mmHg, 10 mmHg, and 15 mmHg), the areas under the ROC curves of SVV were 0.864, 0.759, 0.718, and 0.521, the area under the ROC of PPV were 0.873, 0.792,0.705, and 0.505, and the area under the ROC of PVI were 0.851, 0.765 ,0.709, and 0.512. Under PEEP=0 mmHg, the diagnostic thresholds of SVV, PPV, and PVI were 10.5, 11.5, and 13.5. Under PEEP=5 mmHg, the diagnostic thresholds of SVV,PPV, and PVI were 11.5,13.5, and 14.5.Under PEEP=10 mmHg,the diagnostic thresholds of SVV, PPV, and PVI were 13.5,14.5, and 16.5.In the prone position,there was a significant correlation between SVV,PPV,PVI,and PEEP. CONCLUSIONS:SVV,PPV and PVI can predict fluid responsiveness similarly under the PEEP levels of 0,5, and 10 mmHg. Their diagnostic thresholds increases with the PEEP and the diagnostic accuracies decrease with the PEEP. However, under the PEEP level of 15 mmHg, SVV, PPV, and PVI can not predict fluid responsiveness accurately.
Noninvasive pulse pressure variation and stroke volume variation to predict fluid responsiveness at multiple thresholds: a prospective observational study.
Vos Jaap Jan,Poterman Marieke,Salm Pieternel Papineau,Van Amsterdam Kai,Struys Michel M R F,Scheeren Thomas W L,Kalmar Alain F
Canadian journal of anaesthesia = Journal canadien d'anesthesie
BACKGROUND:Pulse pressure variation (PPV) and stroke volume variation (SVV) are dynamic preload variables that can be measured noninvasively to assess fluid responsiveness (FR) in anesthetized patients with mechanical ventilation. Few studies have examined the effectiveness of predicting FR according to the definition of FR, and assessment of inconclusive values of PPV and SVV around the cut-off value (the "grey zone") might improve individual FR prediction. We explored the ability of noninvasive volume clamp derived measurements of PPV and SVV to predict FR using the grey zone approach, and we assessed the influence of multiple thresholds on the predictive ability of the numerical definition of FR. METHODS:Ninety patients undergoing general surgery were included in this prospective observational study and received a 500 mL fluid bolus as deemed clinically required by the attending anesthesiologist. A minimal relative increase in stroke volume index (↑SVI) was used to define FR with different thresholds from 10-25%. The PPV, SVV, and SVI were measured using the Nexfin® device that employs noninvasive volume clamp plethysmography. RESULTS:The area under the receiver operator characteristic curve gradually increased for PPV / SVV with higher threshold values (from 0.818 / 0.760 at 10% ↑SVI to 0.928 / 0.944 at 25% ↑SVI). The grey zone limits of both PPV and SVV changed from 9-16% (PPV) and 5-13% (SVV) at the 10% ↑SVI threshold to 18-21% (PPV) and 14-16% (SVV) at the 25% ↑SVI threshold. CONCLUSION:Noninvasive PPV and SVV measurements allow an acceptable FR prediction, although the reliability of both variables is dependent on the intended increase in SVI, which improves substantially with concomitant smaller grey zones at higher ↑SVI thresholds.
Automated stroke volume and pulse pressure variations predict fluid responsiveness in mechanically ventilated patients with obstructive jaundice.
Zhao Feng,Wang Peng,Pei Shujun,Mi Weidong,Fu Qiang
International journal of clinical and experimental medicine
BACKGROUND AND OBJECTIVES:Stroke volume variation (SVV) and the pulse pressure variation (PPV) have been found to be effective in prediction fluid responsiveness especially in high risk operations. The objective of this study is to validate the ability of SVV obtained by FloTrac/Vigileo system and PPV obtained by IntelliVue MP System to predict fluid responsiveness in patients with obstructive jaundice during mechanical ventilation. METHODS:Twentyfive patients with obstructive jaundice (mean serum total bilirubin 175.0 ± 120.8 μmol/L), who accepted volume expansion and were hemodynamically stable after induction of anesthesia, were included in the study. SVV and PPV were recorded simultaneously before and after an intravascular volume expansion. Patients with a stroke volume index (SVI) increase of more than 10% after volume expansion were considered as responders. RESULTS:The agreement (mean bias ± SD) between SVV and PPV was -0.2% ± 1.56%. Before volume expansion, SVV and PPV were significantly higher in responders compared to non-responders (P<0.001, P<0.001). Significant correlation was observed between the baseline value of SVV and PPV and the percent change in SVI after fluid expansion (r=0.654, P<0.001; r=0.592, P=0.002). Area under the receiver operating characteristic curves of SVV (0.955) and PPV (0.875) were comparable (P=0.09). The optimal threshold values in predicting fluid responsiveness were 10% for SVV and 8% for PPV. CONCLUSION:In conclusion, SVV obtained by FloTrac/Vigileo system and PPV obtained by IntelliVue MP System was able to predict fluid responsiveness in patients with obstructive jaundice.
Pulse Pressure Variation and Weight-Loss Percentage Predict Hypotension After Anesthesia Induction in Neurosurgery Patients: A Prospective, Observational, Blinded Study.
Ali Achmet,Altiparmak Oguzhan,Tetik Aylin,Altun Demet,Sivrikoz Nukhet,Buget Mehmet,Bolsoy Sahika,Yaman Nihan,Akinci Ibrahim O
Journal of neurosurgical anesthesiology
BACKGROUND:Hypotension after anesthesia induction is a common problem and is partly related to patient volume status. The present study aimed to investigate the correlation between blood pressure change and pulse pressure variation (PPV), and percentage of weight loss while determining threshold for hypotension by receiver operating characteristic analysis. METHODS:We analyzed 231 neurosurgery patients. In all patients, propofol was used for standard anesthesia induction. Patient demographics, medical histories, fasting duration, percentage weight loss, baseline blood pressure, and PPV during normal tidal volume breathing and that during forced inspiratory breathing (PPVfi) were recorded. Hemodynamic changes within 10 minutes of intubation were observed. Patients developing hypotension and severe hypotension were determined; lowest mean arterial pressure (MAP) and systolic arterial pressure (SAP) values were recorded, and their differences relative to baseline values were calculated. RESULTS:The incidence of hypotension was 18.6%. Both percentage weight loss and PPVfi were correlated with the changes in MAP and SAP. A PPVfi>14 identified all observed hypotensive episodes with 86% sensitivity and 86.2% specificity, whereas percentage weight loss >1.75% identified all observed hypotensive episodes with 81.4% sensitivity and 70.7% specificity. Furthermore, PPVfi>16.5 identified severe hypotension with 85% sensitivity and 90.5% specificity, whereas percentage weight loss >1.95% identified severe hypotension with 85% sensitivity and 73% specificity. CONCLUSIONS:Percentage weight loss and PPVfi are good predictors of hypotension after anesthesia induction and, thus, may allow anesthesiologists to adopt preventative measures and ensure safer anesthesia induction.
Validity of Pulse Pressure Variation (PPV) Compared with Stroke Volume Variation (SVV) in Predicting Fluid Responsiveness.
Rathore Abhishek,Singh Shalendra,Lamsal Ritesh,Taank Priya,Paul Debashish
Turkish journal of anaesthesiology and reanimation
OBJECTIVE:Static monitors for assessing the fluid status during major surgeries and in critically ill patients have been gradually replaced by more accurate dynamic monitors in modern-day anaesthesia practice. Pulse pressure variation (PPV) and systolic pressure variation (SPV) are the two commonly used dynamic indices for assessing fluid responsiveness. METHODS:In this prospective observational study, 50 patients undergoing major surgeries were monitored for PPV and SPV: after the induction of anaesthesia and after the administration of 500 mL of isotonic crystalloid bolus. Following the fluid bolus, patients with a cardiac output increase of more than 15% were classified as responders and those with an increase of less than 15% were classified as non-responders. RESULTS:There were no significant differences in the heart rate (HR), mean arterial pressure (MAP), PPV, SVV, central venous pressure (CVP) and cardiac index (CI) between responders and non-responders. Before fluid bolus, the stroke volume was significantly lower in responders (p=0.030). After fluid bolus, MAP was significantly higher in responders but there were no significant changes in HR, CVP, CI, PPV and SVV. In both responders and non-responders, PPV strongly correlated with SVV before and after fluid bolus. CONCLUSION:Both PPV and SVV are useful to predict cardiac response to fluid loading. In both responders and non-responders, PPV has a greater association with fluid responsiveness than SVV.
Preload dependency determines the effects of phenylephrine on cardiac output in anaesthetised patients: A prospective observational study.
Rebet Olivier,Andremont Olivier,Gérard Jean-Louis,Fellahi Jean-Luc,Hanouz Jean-Luc,Fischer Marc-Olivier
European journal of anaesthesiology
BACKGROUND:Although phenylephrine is widely used in the operating room to control arterial pressure, its haemodynamic effects remain controversial. OBJECTIVE:We hypothesised that the effect of phenylephrine on cardiac output is affected by preload dependency. DESIGN:A prospective observational study. SETTING:Single-centre, University Hospital of Caen, France. PATIENTS:Fifty ventilated patients undergoing surgery were studied during hypotension before and after administration of phenylephrine. MAIN OUTCOME MEASURES:Cardiac index (CI), stroke volume (SV), corrected flow time, mean arterial pressure, pulse pressure variations (PPV) and systemic vascular resistance index were used to assess effects of changes in preload dependency. RESULTS:Twenty seven (54%) patients were included in the preload-dependent group (PPV ≥ 13%) and 23 (46%) in the preload-independent group (PPV < 13%) before administration of phenylephrine. For the whole cohort, phenylephrine increased mean arterial pressure [58 (±8) mmHg vs. 79 (±13) mmHg; P < 0.0001] and calculated systemic vascular resistance index [2010 (1338; 2481) dyn s cm m vs. 2989 (2155; 3870) dyn s cm m; P < 0.0001]. However, CI and SV decreased in the preload-independent group [2.3 (1.9; 3.7) l min m vs. 1.8 (1.5; 2.7) l min m; P < 0.0001 and 65 (44; 81) ml vs. 56 (39; 66) ml; P < 0.0001 for both] but not in the preload-dependent group [respectively 2.1 (1.8; 3.5) l min m vs. 2.1 (1.8; 3.3) l min m; P = 0.168 and 49 (41; 67) ml vs. 53 (41; 69) ml; P = 0.191]. Corrected flow time increased [294 (47) ms vs. 306 (56) ms; P = 0.031], and PPV decreased [17 (15; 19) % vs.12 (14; 16) %; P < 0.0003] only in the PPV at least 13% group. CONCLUSION:The effects of phenylephrine on CI and SV depend on preload. CI and SV decreased in preload-independent patients through increase in afterload, but were unchanged in those preload-dependent through increased venous return.
Phenylephrine increases cardiac output by raising cardiac preload in patients with anesthesia induced hypotension.
Kalmar A F,Allaert S,Pletinckx P,Maes J-W,Heerman J,Vos J J,Struys M M R F,Scheeren T W L
Journal of clinical monitoring and computing
Induction of general anesthesia frequently induces arterial hypotension, which is often treated with a vasopressor, such as phenylephrine. As a pure α-agonist, phenylephrine is conventionally considered to solely induce arterial vasoconstriction and thus increase cardiac afterload but not cardiac preload. In specific circumstances, however, phenylephrine may also contribute to an increase in venous return and thus cardiac output (CO). The aim of this study is to describe the initial time course of the effects of phenylephrine on various hemodynamic variables and to evaluate the ability of advanced hemodynamic monitoring to quantify these changes through different hemodynamic variables. In 24 patients, after induction of anesthesia, during the period before surgical stimulus, phenylephrine 2 µg kg was administered when the MAP dropped below 80% of the awake state baseline value for > 3 min. The mean arterial blood pressure (MAP), heart rate (HR), end-tidal CO (EtCO), central venous pressure (CVP), stroke volume (SV), CO, pulse pressure variation (PPV), stroke volume variation (SVV) and systemic vascular resistance (SVR) were recorded continuously. The values at the moment before administration of phenylephrine and 5(T) and 10(T) min thereafter were compared. After phenylephrine, the mean(SD) MAP, SV, CO, CVP and EtCO increased by 34(13) mmHg, 11(9) mL, 1.02(0.74) L min, 3(2.6) mmHg and 4.0(1.6) mmHg at T respectively, while both dynamic preload variables decreased: PPV dropped from 20% at baseline to 9% at T and to 13% at T and SVV from 19 to 11 and 14%, respectively. Initially, the increase in MAP was perfectly aligned with the increase in SVR, until 150 s after the initial increase in MAP, when both curves started to dissociate. The dissociation of the evolution of MAP and SVR, together with the changes in PPV, CVP, EtCO and CO indicate that in patients with anesthesia-induced hypotension, phenylephrine increases the CO by virtue of an increase in cardiac preload.
Cardiovascular determinants of resuscitation from sepsis and septic shock.
Guarracino Fabio,Bertini Pietro,Pinsky Michael R
Critical care (London, England)
BACKGROUND:We hypothesized that the cardiovascular responses to Surviving Sepsis Guidelines (SSG)-defined resuscitation are predictable based on the cardiovascular state. METHODS:Fifty-five septic patients treated by SSG were studied before and after volume expansion (VE), and if needed norepinephrine (NE) and dobutamine. We measured mean arterial pressure (MAP), cardiac index (CI), and right atrial pressure (Pra) and calculated pulse pressure and stroke volume variation (PPV and SVV), dynamic arterial elastance (Ea), arterial elastance (Ea) and left ventricular (LV) end-systolic elastance (Ees), Ees/Ea (VAC), LV ejection efficiency (LVeff), mean systemic pressure analogue (Pmsa), venous return pressure gradient (Pvr), and cardiac performance (Eh), using standard formulae. RESULTS:All patients were hypotensive (MAP 56.8 ± 3.1 mmHg) and tachycardic (113.1 ± 7.5 beat min), with increased lactate levels (lactate = 5.0 ± 4.2 mmol L) with a worsened VAC. CI was variable but > 2 L min M in 74%. Twenty-eight-day mortality was 48% and associated with admission lactate, blood urea nitrogen (BUN), and creatinine levels but not cardiovascular state. In all patients, both MAP and CI improved following VE, as well as cardiac contractility (Ees). Fluid administration improved Pra, Pmsa, and Pvr in all patients, whereas both HR and Ea decreased after VE, thus normalizing VAC. CI increases were proportional to baseline PPV and SVV. CI increases proportionally decreased PPV and SVV. VE increased MAP > 65 mmHg in 35/55 patients. MAP responders had higher PPV, SVV, and Ea than non-responders. NE was given to 20/55 patients in septic shock, but increased MAP > 65 mmHg in only 12. NE increased Ea, Ea, Pra, Pmsa, and VAC while decreasing HR, PPV, SVV, and LVeff. MAP responders had higher pre-NE Ees and lower VAC. Dobutamine was given to 6/8 patients who remained hypotensive following NE. It increased Ees, MAP, CI, and LVeff, while decreasing HR, Pra, and VAC. At all times and all steps of the protocol, CI changes were proportional to Pvr changes independent of treatment. CONCLUSIONS:The cardiovascular response to SSG-based resuscitation is highly heterogeneous but predictable from pre-treatment measures of cardiovascular state.
Dynamic prediction of fluid responsiveness during positive pressure ventilation: a review of the physiology underlying heart-lung interactions and a critical interpretation.
Veterinary anaesthesia and analgesia
OBJECTIVE:Cardiovascular responses to hypovolemia and hypotension are depressed during general anesthesia. A considerable number of anesthetized and critically ill animals may not benefit hemodynamically from a fluid bolus; therefore, it is important to have measures for accurate prediction of fluid responsiveness. Static measures of preload, such as central venous pressure, do not provide accurate prediction of fluid responsiveness, whereas dynamic measures of cardiovascular function, obtained during positive pressure ventilation, are highly predictive. This review describes key physiological concepts behind heart-lung interactions during positive pressure ventilation, factors that can modify this relationship and provides the basis for a rational interpretation of the information obtained from dynamic measurements, with a focus on pulse pressure variation (PPV). DATABASE USED:PubMed. Search items used were: heart-lung interaction, positive pressure ventilation, pulse pressure variation, dynamic index of fluid therapy, goal-directed hemodynamic therapy, dogs, cats, pigs, horses and rabbits. CONCLUSIONS:The veterinary literature suggests that targeting specific PPV thresholds should guide fluid therapy in lieu of conventional assessments. Understanding the physiology of heart-lung interactions during intermittent positive pressure ventilation provides a rational basis for interpreting the literature on dynamic indices of fluid responsiveness, including PPV. Clinical trials are needed to evaluate whether goal-directed fluid therapy based on PPV results in improved outcomes in veterinary patient populations.
The effects of hemodynamic management using the trend of the perfusion index and pulse pressure variation on tissue perfusion: a randomized pilot study.
Godai Kohei,Matsunaga Akira,Kanmura Yuichi
JA clinical reports
BACKGROUND:Intraoperative hemodynamic management is challenging because precise assessment of the adequacy of the intravascular volume is difficult during surgery. Perfusion index (PI) has been shown to reflect changes in peripheral circulation perfusion. Pulse pressure variation (PPV) reflects the preload responsiveness. The hypothesis of this study was that hemodynamic management using the trend of the PI and PPV would improve tissue perfusion. METHODS:This was a prospective, randomized, parallel design, single-blind, single-center pilot study. Patients undergoing elective open gynecological surgery requiring a direct arterial line were included. The patients were randomly allocated to two groups. The intervention group received hemodynamic management using the trend of the PI and PPV in an effort to improve tissue perfusion. The control group received hemodynamic management at the discretion of the anesthesia care provider. The primary outcome was the peak lactate level during surgery. The secondary outcomes were the duration of hypotension, intraoperative fluid balance, intraoperative urine output, and postoperative complication rate. Statistical analysis was performed using Student's t test and Fisher's exact test. A P value of < 0.05 was considered statistically significant. RESULTS:Although the intervention significantly decreased the duration of hypotension and intraoperative fluid balance, the peak lactate level was not different between the intervention group and the control group. Intraoperative urine output and postoperative complication rate were not different between the groups. CONCLUSION:Hemodynamic management using the trend of the PI and PPV does not improve tissue perfusion in patients undergoing open gynecological surgery. TRIAL REGISTRATION:This trial was prospectively registered on a publicly accessible database (UMIN Clinical Trials Registry ID: UMIN 000026957. Registered 12 April 2017, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000030916 ).
Use of pulse pressure variation to estimate changes in preload during experimental acute normovolemic hemodilution.
Sant'Ana A J,Otsuki D A,Noel-Morgan J,Leite V F,Fantoni D T,Abrahao Hajjar L,Barbosa Gomes Galas F R,Pinheiro De Almeida J,Fukushima J,Costa Auler J O
BACKGROUND:Acute normovolemic hemodilution (ANH) is an alternative to blood transfusion in surgeries involving blood loss. This experimental study was designed to evaluate whether pulse pressure variation (PPV) would be an adequate tool for monitoring changes in preload during ANH, as assessed by transesophageal echocardiography. METHODS:Twenty-one anesthetized and mechanically ventilated pigs were randomized into three groups: CTL (control), HES (hemodilution with 6% hydroxyethyl starch at a 1:1 ratio) or NS (hemodilution with saline 0.9% at a 3:1 ratio). Hemodilution was performed in animals of groups NS and HES in two stages, with target hematocrits 22% and 15%, achieved at 30-minute intervals. After two hours, 50% of the blood volume withdrawn was transfused and animals were monitored for another hour. Statistical analysis was based on ANOVA for repeated measures followed by multiple comparison test (P<0.05). Pearson's correlations were performed between changes in left ventricular end-diastolic volume (LVEDV) and PPV, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP). RESULTS:Group NS received a significantly greater amount of fluids during ANH (NS, 900 ± 168 mL vs. HES, 200 ± 50 mL, P<0.05) and presented greater urine output (NS, 2643 ± 1097 mL vs. HES, 641 ± 338 mL, P<0.001). Significant decreases in LVEDV were observed in group NS from completion of ANH until transfusion. In group HES, only increases in LVEDV were observed, at the end of ANH and at transfusion. Such changes in LVEDV (∆LVEDV) were better reflected by changes in PPV (∆PPV, R=-0.62) than changes in CVP (∆CVP, R=0.32) or in PAOP (∆PAOP, R=0.42, respectively). CONCLUSION:Changes in preload during ANH were detected by changes in PPV. ∆PPV was superior to ∆PAOP and ∆CVP to this end.
Hemodynamic monitoring and management of patients undergoing high-risk surgery: a survey among Chinese anesthesiologists.
Chen Guo,Zuo Yunxia,Yang Lei,Chung Elena,Cannesson Maxime
Journal of biomedical research
Hemodynamic monitoring and optimization improve postoperative outcome during high-risk surgery. However, hemodynamic management practices among Chinese anesthesiologists are largely unknown. This study sought to evaluate the current intraoperative hemodynamic management practices for high-risk surgery patients in China. From September 2010 to November 2011, we surveyed anesthesiologists working in the operating rooms of 265 hospitals representing 28 Chinese provinces. All questionnaires were distributed to department chairs of anesthesiology or practicing anesthesiologists. Once completed, the 29-item questionnaires were collected and analyzed. Two hundred and 10 questionnaires from 265 hospitals in China were collected. We found that 91.4% of anesthesiologists monitored invasive arterial pressure, 82.9% monitored central venous pressure (CVP), 13.3% monitored cardiac output (CO), 10.5% monitored mixed venous saturation, and less than 2% monitored pulse pressure variation (PPV) or systolic pressure variation (SPV) during high-risk surgery. The majority (88%) of anesthesiologists relied on clinical experience as an indicator for volume expansion and more than 80% relied on blood pressure, CVP and urine output. Anesthesiologists in China do not own enough attention on hemodynamic parameters such as PPV, SPV and CO during fluid management in high-risk surgical patients. The lack of CO monitoring may be attributed largely to the limited access to technologies, the cost of the devices and the lack of education on how to use them. There is a need for improving access to these technologies as well as an opportunity to create guidelines and education for hemodynamic optimization in China.
Neutrophil-to-lymphocyte ratio and red blood cell distribution width as predictors of microalbuminuria in type 2 diabetes.
Assulyn Tikva,Khamisy-Farah Rola,Nseir William,Bashkin Amir,Farah Raymond
Journal of clinical laboratory analysis
BACKGROUND AND AIM:Chronic inflammation has an important role in the development and progression of type 2 diabetes through immunologic inflammatory mechanisms. Simple new inexpensive inflammatory markers may contribute to the detection of microalbuminuria. Aim of our study is to evaluate the predictive value of neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), and red blood cell distribution width (RDW) for microalbuminuria in type 2 diabetic patients for possible application as prognostic factors for the prediction of microalbuminuria and the progression of disease in patients with diabetes. METHODS:A total of 168 patients with type 2 diabetes mellitus were classified into gender- and BMI-matched three groups according to hemoglobin A1c and microalbuminuria: Group A: 53 patients with controlled diabetes, Group B: 57 patients with uncontrolled diabetes, both without microalbuminuria, and Group C: 58 patients with uncontrolled diabetes with microalbuminuria. Levels of NLR, MPV, and RDW between the study groups were examined and compared. RESULTS:A significant difference in NLR was found between Group C and groups A and B (P < .001, P = .005, respectively). A statistically significant difference in RDW was found between groups B and C (P = .014). Receiver operating characteristic curve analysis of inflammatory markers and microalbuminuria prediction showed an area under curve (AUC) of 0.675 for NLR (CI 0.58-0.76, P < .001) and 0.614 for RDW (CI 0.52-0.70, P = .013). NLR value of 2.54 has 39.7% sensitivity, 78.8% specificity, and 45% positive predictive value (PPV). RDW value of 14.44 has 37.9% sensitivity, 76% specificity, and 41.5% PPV. CONCLUSIONS:Neutrophil-to-lymphocyte ratio and RDW have PPV for microalbuminuria in diabetic patients.
[Pulse pressure variation guided fluid therapy during kidney transplantation: a randomized controlled trial].
De Cassai Alessandro,Bond Ottavia,Marini Silvia,Panciera Giulio,Furian Lucrezia,Neri Flavia,Andreatta Giulio,Rigotti Paolo,Feltracco Paolo
Brazilian journal of anesthesiology (Elsevier)
PURPOSE:Kidney transplantation is the gold-standard treatment for end stage renal disease. Although different hemodynamic variables, like central venous pressure and mean arterial pressure, have been used to guide volume replacement during surgery, the best strategy still ought to be determined. Respiratory arterial Pulse Pressure Variation (PPV) is recognized to be a good predictor of fluid responsiveness for perioperative hemodynamic optimization in operating room settings. The aim of this study was to investigate whether a PPV-guided fluid management strategy is better than a liberal fluid strategy during kidney transplantation surgeries. Identification of differences in urine output in the first postoperative hour was the main objective of this study. METHODS:We conducted a prospective, single blind, randomized controlled trial. We enrolled 40 patients who underwent kidney transplantation from deceased donors. Patients randomized in the PPV Group received fluids whenever PPV was higher than 12%, patients in the Free Fluid Group received fluids following our institutional standard care protocol for kidney transplantations (10mL.kg.h). RESULTS:Urinary output was similar at every time-point between the two groups, urea was statistically different from the third postoperative day with a peak at the fourth postoperative day and creatinine showed a similar trend, being statistically different from the second postoperative day. Urea, creatinine and urine output were not different at the hospital discharge. CONCLUSION:PPV-guided fluid therapy during kidney transplantation significantly improves urea and creatinine levels in the first week after kidney transplantation surgery.
Comparison of restrictive fluid therapy with goal-directed fluid therapy for postoperative delirium in patients undergoing spine surgery: a randomized controlled trial.
Wang Duo Duo,Li Yun,Hu Xian Wen,Zhang Mu Chun,Xu Xing Mei,Tang Jia
Perioperative medicine (London, England)
BACKGROUND:Postoperative delirium (POD) is a common phenomenon after spinal surgery. Intraoperative fluid management may affect POD. The aim of this study was to compare the effects of restrictive fluid therapy (RF) with those of goal-directed fluid therapy (GDT) on POD. METHODS:A total of 195 patients aged ≥ 50 years who underwent spinal surgery were randomly divided into two groups: the RF group and the GDT group. In group RF, a bolus of lactated Ringer's solution was administered at a dose of 5 mL·kg before the induction of anesthesia, followed by a dose of 5 mL·kg·h until the end of surgery. For patients in the GDT group, in addition to the initial administration of lactated Ringer's solution at 5 mL·kg, the subsequent fluid therapy was adjusted by using a continuous noninvasive arterial pressure (CNAP) monitoring system to maintain pulse pressure variation (PPV) ≤ 14%. The primary endpoint was the incidence of POD, assessed once daily with the Confusion Assessment Method-Chinese Reversion (CAM-CR) scale at 1-3 days postoperatively. The secondary endpoints were intraoperative fluid infusion volume, urine volume, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), regional cerebral oxygen saturation (rSO) value, lactic acid value, and visual analog scale (VAS) pain score at 1-3 days after surgery. Moreover, postoperative complications and the length of hospital stay were recorded. RESULTS:The incidence of POD was lower in the GDT group than in the RF group (12.4% vs 4.1%; P = 0.035) in the first 3 days after spine surgery. Compared to group RF, group GDT exhibited a significantly increased volume of intraoperative lactated Ringer's solution [1500 (interquartile range: 1128 to 1775) mL vs 1000 (interquartile range: 765 to 1300) mL, P < 0.001] and urine volume [398 (interquartile range: 288 to 600) mL vs 300 (interquartile range: 200 to 530) mL, P = 0.012]. Intraoperative MAP, CI and rSO values were higher in the GDT group than in the RF group (P < 0.05). Moreover, the length of hospital stay [17.0 (14 to 20) days versus 14.5 (13 to 17.0) days, P = 0.001] was shorter in the GDT group than in the RF group. CONCLUSIONS:GDT reduced the incidence of POD in middle- and old-aged patients undergoing spinal surgery possibly by stabilizing perioperative hemodynamic and improving the supply and demand of oxygen. TRIAL REGISTRATION:ChiCTR2000032603 ; Registered on May 3, 2020.
Bi-level positive pressure ventilation and adaptive servo ventilation in patients with heart failure and Cheyne-Stokes respiration.
Fietze Ingo,Blau Alexander,Glos Martin,Theres Heinz,Baumann Gert,Penzel Thomas
OBJECTIVES:Nocturnal positive pressure ventilation (PPV) has been shown to be effective in patients with impaired left ventricular ejection fraction (LVEF) and Cheyne-Stokes respiration (CSR). We investigated the effect of a bi-level PPV and adaptive servo ventilation on LVEF, CSR, and quantitative sleep quality. METHODS:Thirty-seven patients (New York heart association [NYHA] II-III) with LVEF<45% and CSR were investigated by electrocardiography (ECG), echocardiography and polysomnography. The CSR index (CSRI) was 32.3+/-16.2/h. Patients were randomly treated with bi-level PPV using the standard spontaneous/timed (S/T) mode or with adaptive servo ventilation mode (AutoSetCS). After 6 weeks, 30 patients underwent control investigations with ECG, echocardiography, and polysomnography. RESULTS:The CSRI decreased significantly to 13.6+/-13.4/h. LVEF increased significantly after 6 weeks of ventilation (from 25.1+/-8.5 to 28.8+/-9.8%, p<0.01). The number of respiratory-related arousals decreased significantly. Other quantitative sleep parameters did not change. The Epworth sleepiness score improved slightly. Daytime blood pressure and heart rate did not change. There were some differences between bi-level PPV and adaptive servo ventilation: the CSRI decreased more in the AutoSetCS group while the LVEF increased more in the bi-level PPV group. CONCLUSIONS:Administration of PPV can successfully attenuate CSA. Reduced CSA may be associated with improved LVEF; however, this may depend on the mode of PPV. Changed LVEF is evident even in the absence of significant changes in blood pressure.
Variability of respiratory parameters and extubation readiness in ventilated neonates.
Kaczmarek Jennifer,Kamlin C Omar Farouk,Morley Colin J,Davis Peter G,Sant'anna Guilherme M
Archives of disease in childhood. Fetal and neonatal edition
BACKGROUND:A spontaneous breathing trial (SBT) has been used to guide suitability of extubation in VLBW infants. Respiratory variability (RV) has been used to assess extubation readiness in adults but was never investigated in preterms. The combination of a SBT and RV may further improve prediction of successful extubation. STUDY DESIGN:Using data previously collected during the SBT, the following respiratory variables were analysed: inspiratory time (T(I)), expiratory time (T(E)), T(I)/total breath time, tidal volume (V(T)) and mean inspiratory flow (V(T)/T(I)). RV was quantified using time-domain analysis for each respiratory variable and expressed as a variability index (VI). The sensitivity, specificity, positive and negative predictive values (PPV and NPV) of the SBT, each VI and combined SBT+VI were calculated. Extubation failure was defined as need of re-intubation within 72 h. RESULTS:A total of 44 infants were included. Successfully (n=36) and unsuccessfully (n=8) extubated infants had similar baseline characteristics and number of breaths analysed. VI for V(T)/T(I)was significantly decreased in the failure group. The combination of the SBT and VI of either T(I)or V(T)were the most accurate predictors of successful extubation with a sensitivity of 100% and specificity of 75% and a PPV and NPV for extubation success of 95% and 100%, respectively. CONCLUSIONS:A significant decrease in V(T)/T(I)variability occurred in infants requiring re-intubation. The combination of a SBT failure and decreased variability in T(I)or V(T)was highly predictive of failure. This combination is promising but requires prospective evaluation in a larger population.
Arterial pulse pressure variation suitability in critical care: A French national survey.
Fischer Marc-Olivier,Mahjoub Yazine,Boisselier Clément,Tavernier Benoît,Dupont Hervé,Leone Marc,Lefrant Jean-Yves,Gérard Jean-Louis,Hanouz Jean-Luc,Fellahi Jean-Luc,
Anaesthesia, critical care & pain medicine
OBJECTIVE:Arterial pulse pressure variation (PPV) has been used as an accurate index to predict fluid responsiveness. However, many confounding factors have been recently described. The aims of this study were to assess the conditions of applicability of PPV in intensive care units (ICU). STUDY DESIGN:A one-day French national survey. PATIENTS AND METHODS:A form assessing the suitability of PPV was completed by practitioners for each critically-ill patient included on a set day. RESULTS:Four hundred and sixty-five patients were included in 36 ICUs. A regular sinus rhythm was noted in 408 (88%) patients and the presence of an arterial line in 324 (70%) patients. One hundred and twenty-seven (27%) patients were mechanically ventilated without spontaneous breathing. Only six patients (1.3%) had no confounding factors modifying the threshold value of the PPV. CONCLUSION:The incidence of ICU patients in whom PPV was suitable and without confounding factors were respectively 18% and 1.3% in this one-day French national survey.
Ventilator-induced central venous pressure variation can predict fluid responsiveness in post-operative cardiac surgery patients.
Cherpanath T G V,Geerts B F,Maas J J,de Wilde R B P,Groeneveld A B,Jansen J R
Acta anaesthesiologica Scandinavica
BACKGROUND:Ventilator-induced dynamic hemodynamic parameters such as stroke volume variation (SVV) and pulse pressure variation (PPV) have been shown to predict fluid responsiveness in contrast to static hemodynamic parameters such as central venous pressure (CVP). We hypothesized that the ventilator-induced central venous pressure variation (CVPV) could predict fluid responsiveness. METHODS:Twenty-two elective cardiac surgery patients were studied post-operatively on the intensive care unit during mechanical ventilation with tidal volumes of 6-8 ml/kg without spontaneous breathing efforts or cardiac arrhythmia. Before and after administration of 500mL hydroxyethyl starch, SVV and PPV were measured using pulse contour analysis by modified Modelflow , while CVP was obtained from a central venous catheter positioned in the superior vena cava. CVPV was calculated as 100 × (CVP -CVP )/[(CVP + CVP /2]. RESULTS:Nineteen patients (86%) were fluid responders defined as an increase in cardiac output of ≥ 15% after fluid administration. CVPV decreased upon fluid loading in responders, but not in non-responders. Baseline CVP values showed no correlation with a change in cardiac output in contrast to baseline SVV (r = 0.60, P = 0.003), PPV (r = 0.58, P = 0.005), and CVPV (r = 0.63, P = 0.002). Baseline values of SVV > 9% and PPV > 8% could predict fluid responsiveness with a sensitivity of 89% and 95%, respectively, both with a specificity of 100%. Baseline CVPV could identify all fluid responders and non-responders correctly at a cut-off value of 12%. There was no difference between the area under the receiver operating characteristic curves of SVV, PPV, and CVPV. CONCLUSION:The use of ventilator-induced CVPV could predict fluid responsiveness similar to SVV and PPV in post-operative cardiac surgery patients.
Risk of Harm Associated With Using Rapid Sequence Induction Intubation and Positive Pressure Ventilation in Patients With Hemorrhagic Shock.
Thompson Patrick,Hudson Anthony J,Convertino Victor A,Bjerkvig Christopher,Eliassen Hakon S,Eastridge Brian J,Irvine-Smith Timm,Braverman Maxwell A,Hellander Stefan,Jenkins Donald H,Rappold Joseph F,Gurney Jennifer M,Glassberg Elon,Cap Andrew P,Aussett Sylviain,Apelseth Torunn O,Williams Steve,Ward Kevin R,Shackelford Stacy A,Stroberg Pierre,Vikeness Bjarne H,Pepe Paul E,Winckler Christopher J,Woolley Tom,Enbuske Stefan,De Pasquale Marc,Boffard Ken D,Austlid Ivar,Fosse Theodore K,Asbjornsen Helge,Spinella Philip C,Strandenes Geir
Journal of special operations medicine : a peer reviewed journal for SOF medical professionals
Based on limited published evidence, physiological principles, clinical experience, and expertise, the author group has developed a consensus statement on the potential for iatrogenic harm with rapid sequence induction (RSI) intubation and positive-pressure ventilation (PPV) on patients in hemorrhagic shock. "In hemorrhagic shock, or any low flow (central hypovolemic) state, it should be noted that RSI and PPV are likely to cause iatrogenic harm by decreasing cardiac output." The use of RSI and PPV leads to an increased burden of shock due to a decreased cardiac output (CO)2 which is one of the primary determinants of oxygen delivery (DO2). The diminishing DO2 creates a state of systemic hypoxia, the severity of which will determine the magnitude of the shock (shock dose) and a growing deficit of oxygen, referred to as oxygen debt. Rapid accumulation of critical levels of oxygen debt results in coagulopathy and organ dysfunction and failure. Spontaneous respiration induced negative intrathoracic pressure (ITP) provides the pressure differential driving venous return. PPV subsequently increases ITP and thus right atrial pressure. The loss in pressure differential directly decreases CO and DO2 with a resultant increase in systemic hypoxia. If RSI and PPV are deemed necessary, prior or parallel resuscitation with blood products is required to mitigate post intervention reduction of DO2 and the potential for inducing cardiac arrest in the critically shocked patient.
A robust Fourier-based method to measure pulse pressure variability.
Biomedical signal processing and control
OBJECTIVE:To propose a new method to estimate pulse pressure variability (PPV) in the arterial blood pressure waveform. METHODS:Traditional techniques of calculating PPV using peak finding have a fundamental flaw that prevents them from accurately resolving PPV for small tidal volumes, limiting the use of PPV to only mechanical ventilated patients. The improved method described here addresses this limitation using Fourier analysis of an oscillatory signal that exhibits a time-varying modulation of its amplitude. The analysis reveals a constraint on the spectral representation that must be satisfied for any oscillatory signal that exhibits a time-varying modulation of its amplitude. This intrinsic mathematical structure is taken advantage of in order to improve the robustness of the algorithm. RESULTS:The applicability of the method is tested using synthetic data and 100 h of physiologic data collected from patients admitted to Texas Children's Hospital. SIGNIFICANCE AND CONCLUSION:The proposed method accurately recovers values of PPV at signal-to-noise ratios six times smaller than the traditional method. This is a significant advance for the potential use of PPV to recognize fluid responsiveness during low tidal volume ventilation or spontaneous breathing for which the signal-to-noise ratio is expected to be small.
Evaluation of the knowledge base of French intensivists and anaesthesiologists as concerns the interpretation of respiratory arterial pulse pressure variation.
Fischer Marc-Olivier,Dechanet Fabien,du Cheyron Damien,Gérard Jean-Louis,Hanouz Jean-Luc,Fellahi Jean-Luc
Anaesthesia, critical care & pain medicine
OBJECTIVE:The aims of the study were to assess the knowledge of intensivists and/or anaesthesiologists concerning respiratory arterial pulse pressure variation (PPV) and to define the criteria used to indicate a fluid challenge. STUDY DESIGN:A prospective observational study. PATIENTS AND METHODS:Intensivists and anaesthesiologists from one region of France were evaluated for their knowledge about the prerequisites (continuous arterial pressure monitoring, regular sinus rhythm, mechanical ventilation without spontaneous breathing) and confounding factors shifting the threshold value of PPV (low tidal volume, decreased pulmonary compliance, low heart rate/respiratory rate ratio, right ventricular dysfunction, and/or intra-abdominal hypertension) using clinical vignettes. Criteria used by physicians to indicate a fluid challenge were also collected. RESULTS:One hundred and forty-five physicians were included in the study. Among them, 87 (60%) knew prerequisites but none of them had full knowledge of all confounding factors. Criteria used to perform a fluid challenge were mainly PPV and the passive leg-raising test for the residents and PPV, blood pressure, oliguria and hydric balance for the qualified physicians. CONCLUSIONS:PPV was widely employed to indicate a fluid challenge and 60% of the physicians knew the prerequisites. However, the physicians did not correctly interpret all confounding factors.
Internal carotid artery blood flow in healthy awake subjects is reduced by simulated hypovolemia and noninvasive mechanical ventilation.
Skytioti Maria,Søvik Signe,Elstad Maja
Intact cerebral blood flow (CBF) is essential for cerebral metabolism and function, whereas hypoperfusion in relation to hypovolemia and hypocapnia can lead to severe cerebral damage. This study was designed to assess internal carotid artery blood flow (ICA-BF) during simulated hypovolemia and noninvasive positive pressure ventilation (PPV) in young healthy humans. Beat-by-beat blood velocity (ICA and aorta) were measured by Doppler ultrasound during normovolemia and simulated hypovolemia (lower body negative pressure), with or without PPV in 15 awake subjects. Heart rate, plethysmographic finger arterial pressure, respiratory frequency, and end-tidal CO (ETCO) were also recorded. Cardiac index (CI) and ICA-BF were calculated beat-by-beat. Medians and 95% confidence intervals and Wilcoxon signed rank test for paired samples were used to test the difference between conditions. Effects on ICA-BF were modeled by linear mixed-effects regression analysis. During spontaneous breathing, ICA-BF was reduced from normovolemia (247, 202-284 mL/min) to hypovolemia (218, 194-271 mL/min). During combined PPV and hypovolemia, ICA-BF decreased by 15% (200, 152-231 mL/min, P = 0.001). Regression analysis attributed this fall to concurrent reductions in CI (β: 43.2, SE: 17.1, P = 0.013) and ETCO (β: 32.8, SE: 9.3, P = 0.001). Mean arterial pressure was maintained and did not contribute to ICA-BF variance. In healthy awake subjects, ICA-BF was significantly reduced during simulated hypovolemia combined with noninvasive PPV Reductions in CI and ETCO had additive effects on ICA-BF reduction. In hypovolemic patients, even low-pressure noninvasive ventilation may cause clinically relevant reductions in CBF, despite maintained arterial blood pressure.
Non-invasive positive-pressure ventilation with positive end-expiratory pressure counteracts inward air leaks during preoxygenation: a randomised crossover controlled study in healthy volunteers.
Hanouz J-L,Le Gall F,Gérard J-L,Terzi N,Normand H
British journal of anaesthesia
BACKGROUND:During preoxygenation, the lack of tight fit between the mask and the patient's face results in inward air leak preventing effective preoxygenation. We hypothesized that non-invasive positive-pressure ventilation and positive end-expiratory pressure (PEEP) could counteract inward air leak. METHODS:Healthy volunteers were randomly assigned to preoxygenated through spontaneous breathing without leak (SB), spontaneous breathing with a calibrated air leak (T-shaped piece between the mouth and the breathing system; SB-leak), or non-invasive positive inspiratory pressure ventilation (inspiratory support +6 cm HO; PEEP +5 cm HO) with calibrated leak (PPV-leak). The volunteers breathed through a mouthpiece connected to an anaesthesia ventilator. The expired oxygen fraction (FeO) and air-leak flow (ml s) were measured. The primary end point was the proportion of volunteers with FeO >90% at 3 min. The secondary end points were FeO at 3 min, time to reach FeO of 90%, and the inspiratory air-leak flow. RESULTS:Twenty healthy volunteers were included. The proportion of volunteers with FeO >90% at 3 min was 0% in the SB-leak group, 95% in the SB group, and 100% in the PPV-leak group (P<0.001). At 3 min, the mean [standard deviation (sd)] FeO was 89 (1)%, 76 (1)%, and 90 (0)% in the SB, SB-leak, and PPV-leak groups, respectively (P<0.001). The mean (sd) inward air leak was 59 (12) ml s in the SB-leak group, but 0 (0) ml s in the PPV-leak group (P<0.001). CONCLUSIONS:Preoxygenation through non-invasive positive-pressure ventilation and PEEP provided effective preoxygenation despite an inward air leak. CLINICAL TRIAL REGISTRATION:NCT03087825.
Reliability of Passive Leg Raising, Stroke Volume Variation and Pulse Pressure Variation to Predict Fluid Responsiveness During Weaning From Mechanical Ventilation After Cardiac Surgery: A Prospective, Observational Study.
Hofer Christoph Karl,Geisen Martin,Hartnack Sonja,Dzemali Omer,Ganter Michael Thomas,Zollinger Andreas
Turkish journal of anaesthesiology and reanimation
OBJECTIVE:During assisted ventilation and spontaneous breathing, functional haemodynamic parameters, including stroke volume variation (SVV) and pulse pressure variation (PPV), are of limited value to predict fluid responsiveness, and the passive leg raising (PLR) manoeuvre has been advocated as a surrogate method. We aimed to study the predictive value of SVV, PPV and PLR for fluid responsiveness during weaning from mechanical ventilation after cardiac surgery. METHODS:Haemodynamic variables and fluid responsiveness were assessed in 34 patients. Upon arrival at the intensive care unit, measurements were performed during continuous mandatory ventilation (CMV) and spontaneous breathing with pressure support (PSV) and after extubation (SPONT). The prediction of a positive fluid responsiveness (defined as stroke volume increase >15% after fluid administration) was tested by calculating the specific receiver operating characteristic (ROC) curves. RESULTS:A significant increase in stroke volumes was observed during CMV, PSV and SPONT after fluid administration. There were 19 fluid responders (55.9%) during CMV, with 22 (64.7%) and 13 (40.6%) during PSV and SPONT, respectively. The predictive value for a positive fluid responsiveness (area under the ROC curve) for SVV was 0.88, 0.70 and 0.56; was 0.83, 0.69 and 0.48 for PPV; was 0.72, 0.74 and 0.70 for PLR during CMV, PSV and SPONT, respectively. CONCLUSION:During mechanical ventilation, adequate prediction of fluid responsiveness using SVV and PPV was observed. However, during spontaneous breathing, the reliability of SVV and PPV was poor. In this period, PLR as a surrogate was able to predict fluid responsiveness better than SVV or PPV but was less reliable than previously reported.
The Breathing Effort of Very Preterm Infants at Birth.
Huberts Tom J P,Foglia Elizabeth E,Narayen Ilona C,van Vonderen Jeroen J,Hooper Stuart B,Te Pas Arjan B
The Journal of pediatrics
OBJECTIVE:To compare the respiratory effort of very preterm infants receiving positive pressure ventilation (PPV) with infants breathing on continuous positive airway pressure (CPAP), directly after birth. STUDY DESIGN:Recorded resuscitations of very preterm infants receiving PPV or CPAP after birth were analyzed retrospectively. The respiratory effort (minute volume and recruitment breaths [>8 mL/kg], heart rate, oxygen saturation, and oxygen requirement were analyzed for the first 2 minutes and in the fifth minute after birth. RESULTS:Respiratory effort was analyzed in 118 infants, 87 infants receiving PPV and 31 infants receiving CPAP (median gestational age, 28 weeks [IQR, 26-29] vs 29 weeks [IQR, 29-30; P < .001); birth weight, 1059 g [IQR, 795-1300] vs 1205 g [IQR, 956-1418; P = .06]). The minute volume of spontaneous breaths of infants receiving PPV was lower at 2 minutes (37 mL/kg/minute [IQR, 15-69] vs 188 mL/kg/minute [IQR, 128-297; P < .001]) and at 5 minutes (112 mL/kg/minute [IQR, 46-229] vs 205 mL/kg/minute [IQR, 174-327; P < .001]). Recruitment breaths occurred less in the PPV group at 2 minutes (0 breaths/minute [IQR, 0-1] vs 4 breaths/minute [IQR, 1-8; P < .001]) and 5 minutes (0 breaths/minute [IQR, 0-3] vs 2 breaths/minute [IQR, 0-11; P = .01). The heart rate was lower in the PPV group (94 beats/minute [IQR, 68-128] vs 124 beats/minute [IQR, 100-144; P = .02]) as was oxygen saturation (50% [IQR, 35%-66%] vs 67% [IQR, 34%-80%; P = .04]), but not different at 5 minutes (heart rate, 149 beats/minute [IQR, 131-162] vs 150 beats/minute [IQR, 132-160; P = NS]; oxygen saturation , 91% [IQR, 80%-95%] vs 92% [IQR, 89%-97%; P = NS]). The oxygen requirement was higher (at 2 minutes, 30% [IQR, 21%-53%] vs 21% [IQR, 21%-29%; P = .05]; at 5 minutes, 39% [IQR, 22%-91%] vs 22% [IQR, 21%-31%; P = .003]). CONCLUSION:Very preterm infants breathe at birth when receiving PPV, but the respiratory effort was significantly lower when compared with infants receiving CPAP only. The reduced breathing effort observed likely justified applying PPV in most infants.
Supporting breathing of preterm infants at birth: a narrative review.
Martherus Tessa,Oberthuer André,Dekker Janneke,Hooper Stuart B,McGillick Erin V,Kribs Angela,Te Pas Arjan B
Archives of disease in childhood. Fetal and neonatal edition
Most very preterm infants have difficulty aerating their lungs and require respiratory support at birth. Currently in clinical practice, non-invasive ventilation in the form of continuous positive airway pressure (CPAP) and positive pressure ventilation (PPV) is applied via facemask. As most very preterm infants breathe weakly and unnoticed at birth, PPV is often administered. PPV is, however, frequently ineffective due to pressure settings, mask leak and airway obstruction. Meanwhile, high positive inspiratory pressures and spontaneous breathing coinciding with inflations can generate high tidal volumes. Evidence from preclinical studies demonstrates that high tidal volumes can be injurious to the lungs and brains of premature newborns. To reduce the need for PPV in the delivery room, it should be considered to optimise spontaneous breathing with CPAP. CPAP is recommended in guidelines and commonly used in the delivery room after a period of PPV, but little data is available on the ideal CPAP strategy and CPAP delivering devices and interfaces used in the delivery room. This narrative review summarises the currently available evidence for why PPV can be inadequate at birth and what is known about different CPAP strategies, devices and interfaces used the delivery room.
Arterial Pulse Pressure Variation with Mechanical Ventilation.
Teboul Jean-Louis,Monnet Xavier,Chemla Denis,Michard Frédéric
American journal of respiratory and critical care medicine
Fluid administration leads to a significant increase in cardiac output in only half of ICU patients. This has led to the concept of assessing fluid responsiveness before infusing fluid. Pulse pressure variation (PPV), which quantifies the changes in arterial pulse pressure during mechanical ventilation, is one of the dynamic variables that can predict fluid responsiveness. The underlying hypothesis is that large respiratory changes in left ventricular stroke volume, and thus pulse pressure, occur in cases of biventricular preload responsiveness. Several studies showed that PPV accurately predicts fluid responsiveness when patients are under controlled mechanical ventilation. Nevertheless, in many conditions encountered in the ICU, the interpretation of PPV is unreliable (spontaneous breathing, cardiac arrhythmias) or doubtful (low Vt). To overcome some of these limitations, researchers have proposed using simple tests such as the Vt challenge to evaluate the dynamic response of PPV. The applicability of PPV is higher in the operating room setting, where fluid strategies made on the basis of PPV improve postoperative outcomes. In medical critically ill patients, although no randomized controlled trial has compared PPV-based fluid management with standard care, the Surviving Sepsis Campaign guidelines recommend using fluid responsiveness indices, including PPV, whenever applicable. In conclusion, PPV is useful for managing fluid therapy under specific conditions where it is reliable. The kinetics of PPV during diagnostic or therapeutic tests is also helpful for fluid management.
Comparative Analysis of the Collapsibility Index and Distensibility Index of the Inferior Vena Cava Through Echocardiography with Pulse Pressure Variation That Predicts Fluid Responsiveness in Surgical Patients: An Observational Controlled Trial.
Pereira Renan Muralho,Silva Alvaro José Leite Campelo da,Faller Julio,Gomes Brenno Cardoso,Silva João Manoel
Journal of cardiothoracic and vascular anesthesia
OBJECTIVE:The objective for the present study was to compare the collapsibility (IcIVC) and distensibility (IdIVC) indices of the inferior vena cava with pulse pressure variation (PPV) and determine the accuracy and cutoff points of IcIVC and IdIVC that best predict response to intravenous fluid therapy in surgical patients. DESIGN:Observational, prospective, nonblinded, single center. SETTING:Hospital do Servidor Público Estadual de São Paulo, in São Paulo, Brazil. PARTICIPANTS:Volunteer surgical patients. INTERVENTIONS:This prospective study evaluated adult surgical patients before and after they underwent mechanical ventilation. IcIVC and IdIVC measurements were obtained with echocardiography and PPV through arterial catheterization. MEASUREMENTS AND MAIN RESULTS:Twenty-two patients with a mean age of 55.7 ± 10.9 years were included; 31.8% of the study participants had PPV values >13% and were shown to be responsive to fluid. A good correlation was detected between PPV and icIVC (R = 0.71; p < 0.001) and between PPV and idIVC (R = 0.79; p < 0.001). The area under the receiver operating characteristic curve was 0.98 for icIVC (95% confidence interval 0.81-0.99; p < 0.001) and 0.88 for idIVC (95% confidence interval 0.67-0.98; p < 0.001). CONCLUSIONS:PPV was found to have good correlation with the inferior vena cava diameter variation using echocardiography in surgical patients undergoing spontaneous and artificial ventilation. The cutoff values that best predicted PPV >13% were >40% for icIVC and >17.6% for idIVC.
Do changes in pulse pressure variation and inferior vena cava distensibility during passive leg raising and tidal volume challenge detect preload responsiveness in case of low tidal volume ventilation?
Taccheri Temistocle,Gavelli Francesco,Teboul Jean-Louis,Shi Rui,Monnet Xavier
Critical care (London, England)
BACKGROUND:In patients ventilated with tidal volume (Vt) < 8 mL/kg, pulse pressure variation (PPV) and, likely, the variation of distensibility of the inferior vena cava diameter (IVCDV) are unable to detect preload responsiveness. In this condition, passive leg raising (PLR) could be used, but it requires a measurement of cardiac output. The tidal volume (Vt) challenge (PPV changes induced by a 1-min increase in Vt from 6 to 8 mL/kg) is another alternative, but it requires an arterial line. We tested whether, in case of Vt = 6 mL/kg, the effects of PLR could be assessed through changes in PPV (ΔPPV) or in IVCDV (ΔIVCDV) rather than changes in cardiac output, and whether the effects of the Vt challenge could be assessed by changes in IVCDV (ΔIVCDV) rather than changes in PPV (ΔPPV). METHODS:In 30 critically ill patients without spontaneous breathing and cardiac arrhythmias, ventilated with Vt = 6 mL/kg, we measured cardiac index (CI) (PiCCO2), IVCDV and PPV before/during a PLR test and before/during a Vt challenge. A PLR-induced increase in CI ≥ 10% defined preload responsiveness. RESULTS:At baseline, IVCDV was not different between preload responders (n = 15) and non-responders. Compared to non-responders, PPV and IVCDV decreased more during PLR (by - 38 ± 16% and - 26 ± 28%, respectively) and increased more during the Vt challenge (by 64 ± 42% and 91 ± 72%, respectively) in responders. ∆PPV, expressed either as absolute or as percent relative changes, detected preload responsiveness (area under the receiver operating curve, AUROC: 0.98 ± 0.02 for both). ∆IVCDV detected preload responsiveness only when expressed in absolute changes (AUROC: 0.76 ± 0.10), not in relative changes. ∆PPV, expressed as absolute or percent relative changes, detected preload responsiveness (AUROC: 0.98 ± 0.02 and 0.94 ± 0.04, respectively). This was also the case for ∆IVCDV, but the diagnostic threshold (1 point or 4%) was below the least significant change of IVCDV (9[3-18]%). CONCLUSIONS:During mechanical ventilation with Vt = 6 mL/kg, the effects of PLR can be assessed by changes in PPV. If IVCDV is used, it should be expressed in percent and not absolute changes. The effects of the Vt challenge can be assessed on PPV, but not on IVCDV, since the diagnostic threshold is too small compared to the reproducibility of this variable. TRIAL REGISTRATION:Agence Nationale de Sécurité du Médicament et des Produits de santé: ID-RCB: 2016-A00893-48.
PPV May Be a Starting Point to Achieve Circulatory Protective Mechanical Ventilation.
Su Longxiang,Pan Pan,He Huaiwu,Liu Dawei,Long Yun
Frontiers in medicine
Pulse pressure variation (PPV) is a mandatory index for hemodynamic monitoring during mechanical ventilation. The changes in pleural pressure (P) and transpulmonary pressure (P) caused by mechanical ventilation are the basis for PPV and lead to the effect of blood flow. If the state of hypovolemia exists, the effect of the increased P during mechanical ventilation on the right ventricular preload will mainly affect the cardiac output, resulting in a positive PPV. However, P is more influenced by the change in alveolar pressure, which produces an increase in right heart overload, resulting in high PPV. In particular, if spontaneous breathing is strong, the transvascular pressure will be extremely high, which may lead to the promotion of alveolar flooding and increased RV flow. Asynchronous breathing and mediastinal swing may damage the pulmonary circulation and right heart function. Therefore, according to the principle of PPV, a high PPV can be incorporated into the whole respiratory treatment process to monitor the mechanical ventilation cycle damage/protection regardless of the controlled ventilation or spontaneous breathing. Through the monitoring of PPV, the circulation-protective ventilation can be guided at bedside in real time by PPV.
Changes in pulse pressure variation to assess preload responsiveness in mechanically ventilated patients with spontaneous breathing activity: an observational study.
Hamzaoui Olfa,Shi Rui,Carelli Simone,Sztrymf Benjamin,Prat Dominique,Jacobs Frederic,Monnet Xavier,Gouëzel Corentin,Teboul Jean-Louis
British journal of anaesthesia
BACKGROUND:Pulse pressure variation (PPV) is not reliable in predicting preload responsiveness in patients receiving mechanical with spontaneous breathing (SB) activity. We hypothesised that an increase in PPV after a tidal volume (V) challenge (TVC) or a decrease in PPV during passive leg raising (PLR) can predict preload responsiveness in such cases. METHODS:This prospective observational study was performed in two ICUs and included patients receiving mechanical ventilation with SB, for whom the treating physician decided to test preload responsiveness. Transthoracic echocardiography was used to measure the velocity-time integral (VTI) of the left ventricular outflow tract. Patients exhibiting an increase in VTI ≥12% during PLR were defined as PLR+ patients (or preload responders). Then, a TVC was performed by increasing V by 2 ml kg predicted body weight (PBW) for 1 min. PPV was recorded at each step. RESULTS:Fifty-four patients (Simplified Acute Physiology Score II: 60 (25) ventilated with a V of 6.5 (0.8) ml kg PBW, were included. Twenty-two patients were PLR+. The absolute decrease in PPV during PLR and the absolute increase in PPV during TVC discriminated between PLR+ and PLR- patients with area under the receiver operating characteristic (AUROC) curve of 0.78 and 0.73, respectively, and cut-off values of -1% and +2%, respectively. Those AUROC curve values were similar but were significantly different from that of baseline PPV (0.61). CONCLUSION:In patients undergoing mechanical ventilation with SB activity, PPV does not predict preload responsiveness. However, the decrease in PPV during PLR and the increase in PPV during a TVC help discriminate preload responders from non-responders with moderate accuracy. CLINICAL TRIAL REGISTRATION:NCT04369027 (ClinicalTrials.gov).