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    Association of sublingual microcirculation parameters and endothelial glycocalyx dimensions in resuscitated sepsis. Rovas Alexandros,Seidel Laura Mareen,Vink Hans,Pohlkötter Timo,Pavenstädt Hermann,Ertmer Christian,Hessler Michael,Kümpers Philipp Critical care (London, England) BACKGROUND:The endothelial glycocalyx (eGC) covers the luminal surface of the vascular endothelium and plays an important protective role in systemic inflammatory states and particularly in sepsis. Its breakdown leads to capillary leak and organ dysfunction. Moreover, sepsis-induced alterations of sublingual microcirculation are associated with a worse clinical outcome. The present study was performed to investigate the associations between eGC dimensions and established parameters of microcirculation dysfunction in sepsis. METHODS:This observational, prospective, cross-sectional study included 40 participants, of which 30 critically ill septic patients were recruited from intensive care units of a university hospital and 10 healthy volunteers served as controls. The established microcirculation parameters were obtained sublingually and analyzed according to the current recommendations. In addition, the perfused boundary region (PBR), an inverse parameter of the eGC dimensions, was measured sublingually, using novel data acquisition and analysis software (GlycoCheck™). Moreover, we exposed living endothelial cells to 5% serum from a subgroup of study participants, and the delta eGC breakdown, measured with atomic force microscopy (AFM), was correlated with the paired PBR values. RESULTS:In septic patients, sublingual microcirculation was impaired, as indicated by a reduced microvascular flow index (MFI) and a reduced proportion of perfused vessels (PPV) compared to those in healthy controls (MFI, 2.93 vs 2.74, p = 0.002; PPV, 98.53 vs 92.58, p = 0.0004). PBR values were significantly higher in septic patients compared to those in healthy controls, indicating damage of the eGC (2.04 vs 2.34, p < 0.0001). The in vitro AFM data correlated exceptionally well with paired PBR values obtained at the bedside (rs = - 0.94, p = 0.02). Both PBR values and microcirculation parameters correlated well with the markers of critical illness. Interestingly, no association was observed between the PBR values and established microcirculation parameters. CONCLUSION:Our findings suggest that eGC damage can occur independently of microcirculatory impairment as measured by classical consensus parameters. Further studies in critically ill patients are needed to unravel the relationship of glycocalyx damage and microvascular impairment, as well as their prognostic and therapeutic importance in sepsis. TRIAL REGISTRATION:Retrospectively registered: Clinicaltrials.gov, NCT03960307. 10.1186/s13054-019-2542-2
    Can venous-to-arterial carbon dioxide differences reflect microcirculatory alterations in patients with septic shock? Ospina-Tascón Gustavo A,Umaña Mauricio,Bermúdez William F,Bautista-Rincón Diego F,Valencia Juan D,Madriñán Humberto J,Hernandez Glenn,Bruhn Alejandro,Arango-Dávila César,De Backer Daniel Intensive care medicine PURPOSE:Septic shock has been associated with microvascular alterations and these in turn with the development of organ dysfunction. Despite advances in video microscopic techniques, evaluation of microcirculation at the bedside is still limited. Venous-to-arterial carbon dioxide difference (Pv-aCO2) may be increased even when venous O2 saturation (SvO2) and cardiac output look normal, which could suggests microvascular derangements. We sought to evaluate whether Pv-aCO2 can reflect the adequacy of microvascular perfusion during the early stages of resuscitation of septic shock. METHODS:Prospective observational study including 75 patients with septic shock in a 60-bed mixed ICU. Arterial and mixed-venous blood gases and hemodynamic variables were obtained at catheter insertion (T0) and 6 h after (T6). Using a sidestream dark-field device, we simultaneously acquired sublingual microcirculatory images for blinded semiquantitative analysis. Pv-aCO2 was defined as the difference between mixed-venous and arterial CO2 partial pressures. RESULTS:Progressively lower percentages of small perfused vessels (PPV), lower functional capillary density, and higher heterogeneity of microvascular blood flow were observed at higher Pv-aCO2 values at both T0 and T6. Pv-aCO2 was significantly correlated to PPV (T0: coefficient -5.35, 95 % CI -6.41 to -4.29, p < 0.001; T6: coefficient, -3.49, 95 % CI -4.43 to -2.55, p < 0.001) and changes in Pv-aCO2 between T0 and T6 were significantly related to changes in PPV (R (2) = 0.42, p < 0.001). Absolute values and changes in Pv-aCO2 were not related to global hemodynamic variables. Good agreement between venous-to-arterial CO2 and PPV was maintained even after corrections for the Haldane effect. CONCLUSIONS:During early phases of resuscitation of septic shock, Pv-aCO2 could reflect the adequacy of microvascular blood flow. 10.1007/s00134-015-4133-2
    Microcirculatory alterations in traumatic hemorrhagic shock. Tachon Guillaume,Harrois Anatole,Tanaka Sebastien,Kato Hiromi,Huet Olivier,Pottecher Julien,Vicaut Eric,Duranteau Jacques Critical care medicine OBJECTIVES:Microcirculatory dysfunction has been well reported in clinical studies in septic shock. However, no clinical studies have investigated microcirculatory blood flow behavior in hemorrhagic shock. The main objective of this study was to assess the time course of sublingual microcirculation in traumatic hemorrhagic shock during the first 4 days after trauma. DESIGN:Prospective observational study. SETTING ICU PATIENTS:Eighteen traumatic hemorrhagic shock patients. INTERVENTIONS:The sublingual microcirculation was estimated at the study inclusion after surgical or angiographic embolization to control bleeding (D1), and then three times at 24-hour intervals (D2, D3, and D4). MEASUREMENTS AND MAIN RESULTS:Sublingual microcirculation was impaired for 72 hours despite restoration of the macrovascular circulation after control of bleeding in traumatic hemorrhagic shock patients. Furthermore, we found significantly higher decreases in the microvascular flow index and proportion of perfused vessels in high Sequential Organ Failure Assessment score patients at D4 (Sequential Organ Failure Assessment score ≥ 6) compared to low Sequential Organ Failure Assessment score patients at D4 (Sequential Organ Failure Assessment score < 6) without any differences in global hemodynamics between these two groups. Finally, the initial proportion of perfused vessels at D1 appears to be a good predictor of high Sequential Organ Failure Assessment score at D4. CONCLUSIONS:Alterations of microcirculation in traumatic hemorrhagic shock patients result from the interplay among hemorrhage-induced tissue hypoperfusion, trauma injuries, inflammatory response, and subsequent resuscitation interventions. Despite restoration of the macrocirculation, the sublingual microcirculation was impaired for at least 72 hours. The initial proportion of perfused vessels appears to be a good predictor of high Sequential Organ Failure Assessment score at D4. Further studies are required to firmly establish the link between microvascular alterations and organ dysfunction in traumatic hemorrhagic shock patients. 10.1097/CCM.0000000000000223
    Poor microcirculatory flow dynamics are associated with endothelial cell damage and glycocalyx shedding after traumatic hemorrhagic shock. Naumann David N,Hazeldine Jon,Midwinter Mark J,Hutchings Sam D,Harrison Paul The journal of trauma and acute care surgery BACKGROUND:Endothelial cell damage and glycocalyx shedding after trauma can increase the risk of inflammation, coagulopathy, vascular permeability, and death. Bedside sublingual video-microscopy may detect worse flow and perfusion associated with this endotheliopathy. We compared markers of endotheliopathy with physical flow dynamics after traumatic hemorrhagic shock. METHODS:Sublingual incident dark field video-microscopy was performed at three time points after injury (<10 hours, 10-30 hours, and 30-50 hours). Values for microcirculatory flow index (MFI), Point Of carE Microcirculation assessment (POEM) score, proportion of perfused vessels (PPV), microcirculatory heterogeneity index (MHI), perfused vessel density (PVD), and total vessel density (TVD) were obtained. ELISAs were performed to measure concentrations of thrombomodulin and syndecan-1 as biomarkers of endothelial cell damage and glycocalyx shedding respectively. Flow parameters were dichotomized to above and below average, and biomarkers compared between groups; below average MFI, POEM, PPV, PVD, and TVD, and above average MHI were considered poor microcirculatory flow dynamics. RESULTS:A total of 155 sublingual video-microscopy clips corresponding to 39 time points from 17 trauma patients were analyzed. Median age was 35 (IQR 25-52); 16/17 were men. Within 10 hours of injury, syndecan-1 concentrations were significantly higher compared to 17 age- and sex-matched healthy controls (30 [IQR 20-44] ng/mL) for worse TVD (78 [IQR 63-417] ng/mL), PVD (156 [IQR 63-590] ng/mL), PPV (249 [IQR 64-578] ng/mL), MFI (249 [IQR 64-578] ng/mL), MHI (45 [IQR] 38-68) ng/mL), and POEM scores (108 [IQR 44-462] ng/mL) (all p < 0.01). Thrombomodulin was also raised within 10 hours of injury when compared to healthy controls (2.9 [IQR 2.2-3.4] ng/mL) for worse PPV (4.1 [IQR 3.4-6.2] ng/mL) and MFI (4.1 [IQR 3.4-6.2] ng/mL) (both p < 0.05). CONCLUSIONS:Endothelial cell damage and glycocalyx shedding are associated with worse flow, density, and heterogeneity within microvessels after traumatic hemorrhagic shock. The clinical utility of these biomarkers and flow parameters at the bedside are yet to be elucidated. LEVEL OF EVIDENCE:Prognostic study, level III. 10.1097/TA.0000000000001695
    Microcirculatory perfusion disturbances in septic shock: results from the ProCESS trial. Massey Michael J,Hou Peter C,Filbin Michael,Wang Henry,Ngo Long,Huang David T,Aird William C,Novack Victor,Trzeciak Stephen,Yealy Donald M,Kellum John A,Angus Derek C,Shapiro Nathan I, Critical care (London, England) BACKGROUND:We sought to determine the effects of alternative resuscitation strategies on microcirculatory perfusion and examine any association between microcirculatory perfusion and mortality in sepsis. METHODS:This was a prospective, formally designed substudy of participants in the Protocolized Care in Early Septic Shock (ProCESS) trial. We recruited from six sites with the equipment and training to perform these study procedures. All subjects were adults with septic shock, and each was assigned to alternative resuscitation strategies. The two main analyses assessed (1) the impact of resuscitation strategies on microcirculatory perfusion parameters and (2) the association of microcirculatory perfusion with 60-day in-hospital mortality. We measured sublingual microcirculatory perfusion using sidestream dark field in vivo video microscopy at the completion of the 6-h ProCESS resuscitation protocol and then again at 24 and 72 h. RESULTS:We enrolled 207 subjects (demographics were similar to the overall ProCESS cohort) and observed 40 (19.3%) deaths. There were no differences in average perfusion characteristics between treatment arms. Analyzing the relationship between microcirculatory perfusion and mortality, we found an association between vascular density parameters and mortality. Total vascular density (beta = 0.006, p < 0.003), perfused vascular density (beta = 0.005, p < 0.04), and De Backer score (beta = 0.009, p < 0.01) were higher overall in survivors in a generalized estimating equation model, and this association was significant at the 72-h time point (p < 0.05 for each parameter). CONCLUSIONS:Microcirculatory perfusion did not differ between three early septic shock treatment arms. We found an association between microcirculatory perfusion parameters of vascular density at 72 h and mortality. TRIAL REGISTRATION:ClinicalTrials.gov, NCT00510835 . Registered on August 2, 2007. 10.1186/s13054-018-2240-5
    Effects of capillary refill time-vs. lactate-targeted fluid resuscitation on regional, microcirculatory and hypoxia-related perfusion parameters in septic shock: a randomized controlled trial. Castro Ricardo,Kattan Eduardo,Ferri Giorgio,Pairumani Ronald,Valenzuela Emilio Daniel,Alegría Leyla,Oviedo Vanessa,Pavez Nicolás,Soto Dagoberto,Vera Magdalena,Santis César,Astudillo Brusela,Cid María Alicia,Bravo Sebastian,Ospina-Tascón Gustavo,Bakker Jan,Hernández Glenn Annals of intensive care BACKGROUND:Persistent hyperlactatemia has been considered as a signal of tissue hypoperfusion in septic shock patients, but multiple non-hypoperfusion-related pathogenic mechanisms could be involved. Therefore, pursuing lactate normalization may lead to the risk of fluid overload. Peripheral perfusion, assessed by the capillary refill time (CRT), could be an effective alternative resuscitation target as recently demonstrated by the ANDROMEDA-SHOCK trial. We designed the present randomized controlled trial to address the impact of a CRT-targeted (CRT-T) vs. a lactate-targeted (LAC-T) fluid resuscitation strategy on fluid balances within 24 h of septic shock diagnosis. In addition, we compared the effects of both strategies on organ dysfunction, regional and microcirculatory flow, and tissue hypoxia surrogates. RESULTS:Forty-two fluid-responsive septic shock patients were randomized into CRT-T or LAC-T groups. Fluids were administered until target achievement during the 6 h intervention period, or until safety criteria were met. CRT-T was aimed at CRT normalization (≤ 3 s), whereas in LAC-T the goal was lactate normalization (≤ 2 mmol/L) or a 20% decrease every 2 h. Multimodal perfusion monitoring included sublingual microcirculatory assessment; plasma-disappearance rate of indocyanine green; muscle oxygen saturation; central venous-arterial pCO gradient/ arterial-venous O content difference ratio; and lactate/pyruvate ratio. There was no difference between CRT-T vs. LAC-T in 6 h-fluid boluses (875 [375-2625] vs. 1500 [1000-2000], p = 0.3), or balances (982[249-2833] vs. 15,800 [740-6587, p = 0.2]). CRT-T was associated with a higher achievement of the predefined perfusion target (62 vs. 24, p = 0.03). No significant differences in perfusion-related variables or hypoxia surrogates were observed. CONCLUSIONS:CRT-targeted fluid resuscitation was not superior to a lactate-targeted one on fluid administration or balances. However, it was associated with comparable effects on regional and microcirculatory flow parameters and hypoxia surrogates, and a faster achievement of the predefined resuscitation target. Our data suggest that stopping fluids in patients with CRT ≤ 3 s appears as safe in terms of tissue perfusion. Clinical Trials: ClinicalTrials.gov Identifier: NCT03762005 (Retrospectively registered on December 3rd 2018). 10.1186/s13613-020-00767-4
    Microcirculatory, Endothelial and Inflammatory Responses in Critically Ill Patients with COVID-19 are Distinct from those Seen in Septic Shock: A Case Control Study. Hutchings Sam D,Watchorn James,Trovato Francesca,Napoli Salvatore,Mujib Salma F,Hopkins Philip,McPhail Mark Shock (Augusta, Ga.) Critically ill patients with COVID-19 infection frequently exhibit a hyperinflammatory response and develop organ failures, however the underlying mechanisms are unclear. We investigated the microcirculatory, endothelial and inflammatory responses in critically ill COVID-19 patients and compared them to a group of patients with septic shock in a prospective observational case control study. 30 critically ill patients with COVID-19 were compared to 33 patients with septic shock.Measurements of sublingual microcirculatory flow using Incident Dark Field (IDF) video-microscopy and serial measurements of IL-6 and Syndecan-1 levels were performed. COVID-19 patients had significantly less vasoactive drug requirement and lower plasma lactate than those with septic shock. Microcirculatory flow was significantly worse in septic patients than those with COVID-19 (MFI 2.6 v 2.9 p 0.02, PPV 88 v 97% p < 0.001). IL-6 was higher in patients with septic shock than COVID-19 (1653 v 253 pg/ml, p 0.03). IL-6 levels in COVID 19 patients were not elevated compared to healthy controls except on the day of ICU admission. Syndecan-1 levels were not different between the 2 pathological groups. Compared to patients with undifferentiated septic shock an overt shock state with tissue hypoperfusion does not appear typical of COVID-19 infection. There was no evidence of significant sublingual microcirculatory impairment, widespread endothelial injury or marked inflammatory cytokine release in this group of critically ill COVID-19 patients. 10.1097/SHK.0000000000001672
    Observational study of the microcirculation in patients with liver cirrhosis. Wythe Stephen,Davies Thomas W,O'Beirne James,Martin Daniel,Gilbert-Kawai Edward JGH open : an open access journal of gastroenterology and hepatology Background and Aim:Liver cirrhosis is associated with widespread microcirculatory dysfunction and hemodynamic derangement, which may play a role in the pathogenesis of multiple organ failure. Little is known, however, about the progression of microvascular alterations as the severity of liver disease worsens. Therefore, our aim is to quantify the peripheral systemic microcirculatory changes associated with increasing severity of liver cirrhosis. Methods:Forty patients with liver cirrhosis were studied and divided into groups based on Child-Pugh classes A ( = 9), B ( = 18), and C ( = 13) for comparison. Incident dark field imaging was used to evaluate the sublingual microcirculation and near-infrared spectroscopy at the thenar eminence to assess microvascular reactivity and function. Results:There was no difference in microcirculatory flow index ( = 0.655), heterogeneity index ( = 0.702), or vessel density ( = 0.923) between the different Child-Pugh groups. Microvascular reactivity did not change as the severity of liver disease worsened. Conclusions:This study showed no association between peripheral systemic microcirculatory alterations and the severity of liver disease. Further research with larger study cohorts are needed to clarify the relationship between microcirculatory abnormalities and disease progression and to establish if the peripheral microcirculation is affected by the pathophysiology of worsening cirrhosis. 10.1002/jgh3.12196
    CHANGES IN SUBLINGUAL MICROCIRCULATION IS CLOSELY RELATED WITH THAT OF BULBAR CONJUNCTIVAL MICROCIRCULATION IN A RAT MODEL OF CARDIAC ARREST. Yin Lu,Yang Zhengfei,Yu Haifang,Qian Jie,Zhao Shen,Wang Jiangang,Wu Xiaobo,Cahoon Jena,Tang Wanchun Shock (Augusta, Ga.) Following successful resuscitation, a significantly impaired microcirculation has been identified. The severity of the impairment of microcirculation is closely related to that of vital organ dysfunction. Sublingual microcirculation is a traditional site for the measurement of tissue perfusion. In the present study, we investigated the bulbar conjunctival microcirculatory alterations following CPR and its relationship with the changes of sublingual microcirculation in a rat model of cardiac arrest.Male Sprague-Dawley rats (450-550 g) were utilized. Ventricular fibrillation was induced and untreated for 8 min followed by 8 min of CPR. Sublingual and bulbar conjunctival microcirculatory blood flow was visualized by a sidestream dark-field imaging device at baseline, 30 min, 1, 2, 4, and 8 h post-resuscitation. Both perfused vessel density (PVD) and microcirculatory flow index (MFI) were recorded.The post-resuscitation PVD and MFI were significantly decreased in both sublingual and bulbar conjunctival sites. Sublingual PVD decreased from baseline of 5.9 ± 0.3 to 3.1 ± 0.4 n/mm at 30 min post-resuscitation and MFI from 3.0 ± 0.0 to 1.5 ± 0.3 (both P < 0.05 vs. baseline). Bulbar conjunctival PVD was significantly reduced from baseline of 6.5 ± 0.6 to 3.9 ± 0.5 n/mm at 30 min post-resuscitation and MFI from 3.0 ± 0.0 to 1.2 ± 0.4 (both P < 0.05 vs. baseline). PVD, MFI, and cardiac function did not change significantly from the 30-min measurements in the surviving rats throughout the remainder of the study (both P > 0.05 vs. 30-min post-resuscitation). The decreases in sublingual microcirculatory blood flow were closely correlated with the reductions of bulbar conjunctival microcirculatory blood flow (PVD: r = 0.87, P < 0.05; MFI: r = 0.92, P < 0.05). Myocardial function was significantly impaired in all animals after resuscitation when compared with baseline values (P < 0.05). The impairments of both sublingual and bulbar conjunctival microcirculation were significantly correlated with the impairment of myocardial function.In the rat model of cardiac arrest, the changes in sublingual microcirculatory blood flow are closely correlated with that of bulbar conjunctival microcirculatory blood flow after successful resuscitation. The changes are correlated with the severity of post-resuscitation myocardial dysfunction. Our study testified sublingual site could be substituted by bulbar conjunctival at least in the rat model of cardiac arrest. The measurement of conjunctival microcirculation may provide an accessible and convenient option as sublingual site for monitoring microcirculation in humans. 10.1097/SHK.0000000000000508
    Sublingual microcirculation: a case report. Scheuzger Jonas D,Zehnder Anna,Yeginsoy Desirée,Siegemund Martin Journal of medical case reports INTRODUCTION:Sublingual microcirculation monitoring is suitable for bedside use in critically ill patients. We present a case in which severely impaired sublingual microcirculation was the first alarming sign of an early deterioration of the patient's medical situation. CASE PRESENTATION:This is the case of a 58-year-old white woman admitted to our intensive care unit after the removal of parts of her small intestine due to a volvulus. Her microcirculation was checked the day after surgery in terms of an ongoing study and predicted a massive deterioration of her clinical situation. CONCLUSIONS:This case highlights the potential value of monitoring the microcirculation in critically ill patients. Two full hours could have been saved for diagnostic workup and earlier treatment had we considered the impaired microcirculation alone as a warning sign. Regardless of the supposed cause, impaired microcirculation should alert the responsible physician and should be followed by a diagnostic workup. Sublingual microcirculation monitoring can be useful in intensive care units to detect a deteriorated microcirculation earlier than with standard monitoring. 10.1186/s13256-019-2118-4
    Sublingual functional capillary rarefaction in chronic heart failure. Wadowski Patricia P,Hülsmann Martin,Schörgenhofer Christian,Lang Irene M,Wurm Raphael,Gremmel Thomas,Koppensteiner Renate,Steinlechner Barbara,Schwameis Michael,Jilma Bernd European journal of clinical investigation BACKGROUND AND OBJECTIVE:Microcirculatory changes contribute to clinical symptoms and disease progression in chronic heart failure (CHF). A depression of coronary flow reserve is associated with a lower myocardial capillary density in biopsies. We hypothesized that changes in cardiac microcirculation might also be reflected by a systemic reduction in capillaries and visualized by sublingual videomicroscopy. The aim was to study in vivo capillary density and glycocalyx dimensions in patients with CHF vs healthy controls. METHODS:Fifty patients with ischaemic and nonischaemic CHF and standard treatment were compared to 35 healthy age-matched subjects in a prospective cross-sectional study. Sublingual microcirculation was visualized using a sidestream darkfield videomicroscope. Functional and perfused total capillary densities were compared between patients and controls. A reduced glycocalyx thickness was measured by an increased perfused boundary region (PBR). RESULTS:Median functional and total perfused capillary densities were 30% and 45% lower in patients with CHF (both P < .001). Intake of oral vitamin K antagonists was associated with significantly lower capillary densities (P < .05), but not independent of NT-proBNP. Dimensions of the glycocalyx were marginally lower in CHF patients than in healthy controls (<7% difference). However, PBR correlated significantly with inflammation markers (fibrinogen: r = .58; C-reactive protein: r = .42), platelet counts (r = .36) and inversely with measures of liver/renal function such as bilirubin (r = -.38) or estimated glomerular filtration rate (r = -.34) in CHF patients. CONCLUSION:CHF patients have got a markedly lower functional and total perfused capillary density in sublingual microvasculature when compared to controls, indicating a systemic decrease in microcirculation. 10.1111/eci.12869
    High-salt intake affects sublingual microcirculation and is linked to body weight change in healthy volunteers: a randomized cross-over trial. Rorije Nienke M G,Rademaker Emma,Schrooten Esmee M,Wouda Rosa D,Homan Van Der Heide Jacob J,Van Den Born Bert-Jan H,Vogt Liffert Journal of hypertension BACKGROUND:The pathophysiology of salt-sensitive hypertension remains uncertain, but may involve microvascular alterations. High-salt intake decreases microvascular density in hypertensive patients, but due to lack of studies in normotensive patients the causal pathway remains unclear. We studied whether high-salt intake decreases sublingual microvascular density in normotensive individuals and assessed the influence of body weight on changes in microvascular density. METHODS:In an open label randomized cross-over trial 18 healthy men were included to study the effect of a 2-week high-salt (>12 g/day) and low-salt (<3 g/day) diet on microvascular (diameter <20 μm) density with sublingual sidestream darkfield imaging. We used sublingual nitroglycerin (NTG) to recruit microvessels. RESULTS:There was no significant difference in microvascular density between diets (0.96 ± 3.88 mm/mm; P = 0.31, following NTG; and -0.03 ± 1.64 mm/mm; P = 0.95, without NTG). Increased salt intake was correlated with a decrease in microvascular density following NTG (r = -0.47; P = 0.047), but not without NTG (r = 0.06; P = 0.800). The decrease in microvascular density following high-salt intake was significantly larger for those with a large change in body weight as compared with those with a small changer in body weight (-0.79 ± 1.35 and 0.84 ± 1.56 mm/mm respectively, P = 0.031). CONCLUSION:We demonstrate in healthy volunteers that higher salt intake is correlated with decreased sublingual microvascular density following administration of NTG and; larger changes in body weight following high-salt intake coincide with a larger decrease in microvascular density. Changes in microvascular density occurred without blood pressure effects, indicating that high-salt load as such contributes to microvascular changes, and may precede hypertension development. 10.1097/HJH.0000000000002015
    Sublingual microcirculation does not reflect red blood cell transfusion thresholds in the intensive care unit-a prospective observational study in the intensive care unit. Scheuzger Jonas,Zehnder Anna,Meier Vera,Yeginsoy Desirée,Flükiger Julian,Siegemund Martin Critical care (London, England) PURPOSE:Hemoglobin (Hb) transfusion thresholds are established in intensive care units. A restrictive transfusion threshold (Hb 70-75 g/l) is recommended in septic patients, and a liberal transfusion threshold (Hb 90 g/l) for cardiogenic shock. It is unclear whether these historically adopted transfusion thresholds meet the challenges of individual patients. METHODS:We evaluated microvascular flow index (MFI) and proportion of perfused vessels (PPV) in the sublingual microcirculation with CytoCam-IDF microscopy and near-infrared spectroscopy (NIRS). A study team-independent, treating intensivist assigned a total of 64 patients to 1 of 2 two transfusion thresholds, 43 patients to the Hb 75 g/l threshold and 21 patients to the Hb 90 g/l threshold, at a surgical intensive care unit. We performed microcirculatory measurements 1 h before and 1 h after transfusion of 1 unit of red blood cells. RESULTS:Microcirculatory flow variables correlated negatively with pre-transfusion flow variables (ΔMFI: ρ = - 0.821, p <  0.001; ΔPPV: ρ = - 0.778, p <  0.001). Patients with good initial microcirculation (cutoffs: MFI > 2.84, PPV > 88%) showed a deteriorated microcirculation after red blood cell transfusion. An impaired microcirculation improved after transfusion. At both transfusion thresholds, approximately one third of the patients showed an initially impaired microcirculation. In contrast, one third in every group had good microcirculation above the cutoff variables and did not profit from the transfusion. CONCLUSION:The data suggest that the established transfusion thresholds and other hemodynamic variables do not reflect microcirculatory perfusion of patients. Blood transfusion at both thresholds 75 g/l and 90 g/l hemoglobin can either improve or harm the microcirculatory blood flow, questioning the concept of arbitrary transfusion thresholds. 10.1186/s13054-020-2728-7
    Clinical relevance of early sublingual microcirculation monitoring in septic shock patients. Sharawy Nivin,Mahrous Reham,Whynot Sara,George Ronald,Lehmann Christian Clinical hemorheology and microcirculation INTRODUCTION:Although microcirculation dysfunction plays unique role in septic shock, translation of microcirculation to clinical practices is limited by current semi-quantities analysis and unclear clinical relevance of microcirculation monitoring. Our aim was to critically evaluate the characteristic nature and relevant clinical important of microcirculation. EVIDENCE ACQUISITION:Pubmed (2000 to August 2015) were searched to identify observation, case-control, intervention and randomized clinical studies evaluating the relationship between microcirculation alterations and mortality, morbidity and drug responses. The STROBE and CONSORT Statement for assessment of the quality of included studies. EVIDENCE SYNTHESIS:We examined results from 17 observations, 4 randomized controlled trials and one case report published studies. This data set comprised of 637 patients. Early septic shock is associated with hypoperfusion and heterogeneous microcirculation that is associated with hyperlactemia and metabolic acidosis. The evidence on clinical relevance of microcirculation is less striking, mainly due to the limited number of studies and problems related to the methodological protocol of the studies and currently semi-quantitative analysis technique. In particular the baseline and time course of microcirculation alteration appears to be controversial. CONCLUSION:There is lack of evidences of clinical importance of early microcirculation monitoring and mechanism of microcirculation dysfunction in septic shock patients. This could be due to the methodological protocol of the studies and currently semi-quantitative analysis technique. 10.3233/CH-170244