Effect of acyclovir therapy on the outcome of mechanically ventilated patients with lower respiratory tract infection and detection of herpes simplex virus in bronchoalveolar lavage: protocol for a multicentre, randomised controlled trial (HerpMV).

INTRODUCTION: Herpes simplex virus (HSV) is frequently detected in the respiratory tract of mechanically ventilated patients and is associated with a worse outcome. The aim of this study is to determine whether antiviral therapy in HSV-positive patients improves outcome. METHODS AND ANALYSIS: Prospective, multicentre, open-label, randomised, controlled trial in parallel-group design. Adult, mechanically ventilated patients with pneumonia and HSV type 1 detected in bronchoalveolar lavage (≥105 copies/mL) are eligible for participation and will be randomly allocated (1:1) to receive acyclovir (10 mg/kg body weight every 8 hours) for 10 days (or until discharge from the intensive care unit if earlier) or no intervention (control group). The primary outcome is mortality measured at day 30 after randomisation (primary endpoint) and will be analysed with Cox mixed-effects model. Secondary endpoints include ventilator-free and vasopressor-free days up to day 30. A total of 710 patients will be included in the trial. ETHICS AND DISSEMINATION: The trial was approved by the responsible ethics committee and by Germany's Federal Institute for Drugs and Medical Devices. The clinical trial application was submitted under the new Clinical Trials Regulation through CTIS (The Clinical Trials Information System). In this process, only one ethics committee, whose name is unknown to the applicant, and Germany's Federal Institute for Drugs and Medical Devices are involved throughout the entire approval process. Results will be published in a journal indexed in MEDLINE and CTIS. With publication, de-identified, individual participant data will be made available to researchers. TRIAL REGISTRATION NUMBER: NCT06134492.

Assessing SOFA score trajectories in sepsis using machine learning: A pragmatic approach to improve the accuracy of mortality prediction.

INTRODUCTION: An increasing amount of longitudinal health data is available on critically ill septic patients in the age of digital medicine, including daily sequential organ failure assessment (SOFA) score measurements. Thus, the assessment in sepsis focuses increasingly on the evaluation of the individual disease's trajectory. Machine learning (ML) algorithms may provide a promising approach here to improve the evaluation of daily SOFA score dynamics. We tested whether ML algorithms can outperform the conventional ΔSOFA score regarding the accuracy of 30-day mortality prediction. METHODS: We used the multicentric SepsisDataNet.NRW study cohort that prospectively enrolled 252 sepsis patients between 03/2018 and 09/2019 for training ML algorithms, i.e. support vector machine (SVM) with polynomial kernel and artificial neural network (aNN). We used the Amsterdam UMC database covering 1,790 sepsis patients for external and independent validation. RESULTS: Both SVM (AUC 0.84; 95% CI: 0.71-0.96) and aNN (AUC 0.82; 95% CI: 0.69-0.95) assessing the SOFA scores of the first seven days led to a more accurate prognosis of 30-day mortality compared to the ΔSOFA score between day 1 and 7 (AUC 0.73; 95% CI: 0.65-0.80; p = 0.02 and p = 0.05, respectively). These differences were even more prominent the shorter the time interval considered. Using the SOFA scores of day 1 to 3 SVM (AUC 0.82; 95% CI: 0.68 0.95) and aNN (AUC 0.80; 95% CI: 0.660.93) led to a more accurate prognosis of 30-day mortality compared to the ΔSOFA score (AUC 0.66; 95% CI: 0.58-0.74; p < 0.01 and p < 0.01, respectively). Strikingly, all these findings could be confirmed in the independent external validation cohort. CONCLUSIONS: The ML-based algorithms using daily SOFA scores markedly improved the accuracy of mortality compared to the conventional ΔSOFA score. Therefore, this approach could provide a promising and automated approach to assess the individual disease trajectory in sepsis. These findings reflect the potential of incorporating ML algorithms as robust and generalizable support tools on intensive care units.

Adjusting Acute Kidney Injury Kidney Disease: Improving Global Outcomes Urine Output Criterion for Predicted Body Weight Improves Prediction of Hospital Mortality.

BACKGROUND: Based on the Kidney Disease: Improving Global Outcomes (KDIGO) definitions, urine output, serum creatinine, and need for kidney replacement therapy are used for staging acute kidney injury (AKI). Currently, AKI staging correlates strongly with mortality and can be used as a predictive tool. However, factors associated with the development of AKI may affect its predictive ability. We tested whether adjustment for predicted (versus actual) body weight improved the ability of AKI staging to predict hospital mortality. METHODS: A total of 3279 patients who had undergone cardiac surgery in a university hospital were retrospectively analyzed. AKI was staged according to KDIGO criteria (standard staging) and after adjustment for hourly urine output adjusted by predicted body weight for each patient and each day of their hospital stay. RESULTS: The incidence of AKI (all stages) was 43% (predicted body weight adjusted) and 50% (standard staging), respectively ( P < .001). In sensitivity-specificity analyses for predicting hospital mortality, the area under the curve was significantly higher after adjustment for predicted body weight than with standard staging ( P = .002). CONCLUSIONS: Compared to standard staging, adjustment of urine output for predicted body weight increases the specificity and improves prediction of hospital mortality in patients undergoing cardiac surgery.

A model of porcine polymicrobial septic shock.

BACKGROUND: Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Mortality of patients with sepsis is high and largely unchanged throughout the past decades. Animal models have been widely used for the study of sepsis and septic shock, but translation into effective treatment regimes in the clinic have mostly failed. Pigs are considered as suitable research models for human diseases due to their high comparability and similarity to human anatomy, genetics, and the immune system. We here evaluated the previously reported models of septic shock in pigs and established a novel model of polymicrobial sepsis that meets the clinical criteria of septic shock in pigs. MATERIALS AND METHODS: The literature search was performed using the keywords "pig", "sepsis" and "septic shock". For the establishment of septic shock in n = 10 German landrace pigs, mechanical ventilation was initiated, central venous and arterial lines and invasive hemodynamic monitoring via pulse contour cardiac output measurement (PiCCO) established. Peritoneal polymicrobial faecal sepsis was induced by application of 3 g/kg body weight faeces into the abdominal cavity. Septic shock was defined according to the third international consensus definitions (Sepsis-3). Upon shock, pigs underwent the 1-h bundle for the treatment of human sepsis. Cytokine levels were measured by ELISA. RESULTS: Published porcine sepsis models exhibited high methodological variability and did not meet the clinical criteria of septic shock. In our model, septic shock developed after an average of 4.8 ± 0.29 h and was associated with a reproducible drop in blood pressure (mean arterial pressure 54 ± 1 mmHg) and significant hyperlactatemia (3.76 ± 0.65 mmol/L). Septic shock was associated with elevated levels of interleukin-6 (IL6) and initial cardiac depression followed by a hyperdynamic phase with significant loss of systemic vascular resistance index after initial resuscitation. In addition, organ dysfunction (acute kidney injury) occurred. CONCLUSIONS: We here established a model of septic shock in pigs that meets the clinical criteria of septic shock utilized in human patients. Our model may thus serve as a reference for clinically relevant sepsis research in pigs.

Development and validation of an interpretable 3 day intensive care unit readmission prediction model using explainable boosting machines.

Background: Intensive care unit (ICU) readmissions are associated with mortality and poor outcomes. To improve discharge decisions, machine learning (ML) could help to identify patients at risk of ICU readmission. However, as many models are black boxes, dangerous properties may remain unnoticed. Widely used post hoc explanation methods also have inherent limitations. Few studies are evaluating inherently interpretable ML models for health care and involve clinicians in inspecting the trained model. Methods: An inherently interpretable model for the prediction of 3 day ICU readmission was developed. We used explainable boosting machines that learn modular risk functions and which have already been shown to be suitable for the health care domain. We created a retrospective cohort of 15,589 ICU stays and 169 variables collected between 2006 and 2019 from the University Hospital Münster. A team of physicians inspected the model, checked the plausibility of each risk function, and removed problematic ones. We collected qualitative feedback during this process and analyzed the reasons for removing risk functions. The performance of the final explainable boosting machine was compared with a validated clinical score and three commonly used ML models. External validation was performed on the widely used Medical Information Mart for Intensive Care version IV database. Results: The developed explainable boosting machine used 67 features and showed an area under the precision-recall curve of 0.119 ± 0.020 and an area under the receiver operating characteristic curve of 0.680 ± 0.025. It performed on par with state-of-the-art gradient boosting machines (0.123 ± 0.016, 0.665 ± 0.036) and outperformed the Simplified Acute Physiology Score II (0.084 ± 0.025, 0.607 ± 0.019), logistic regression (0.092 ± 0.026, 0.587 ± 0.016), and recurrent neural networks (0.095 ± 0.008, 0.594 ± 0.027). External validation confirmed that explainable boosting machines (0.221 ± 0.023, 0.760 ± 0.010) performed similarly to gradient boosting machines (0.232 ± 0.029, 0.772 ± 0.018). Evaluation of the model inspection showed that explainable boosting machines can be useful to detect and remove problematic risk functions. Conclusions: We developed an inherently interpretable ML model for 3 day ICU readmission prediction that reached the state-of-the-art performance of black box models. Our results suggest that for low- to medium-dimensional datasets that are common in health care, it is feasible to develop ML models that allow a high level of human control without sacrificing performance.

Digital Holographic Microscopy for Label-Free Detection of Leukocyte Alternations Associated with Perioperative Inflammation after Cardiac Surgery.

In a prospective observational pilot study on patients undergoing elective cardiac surgery with cardiopulmonary bypass, we evaluated label-free quantitative phase imaging (QPI) with digital holographic microscopy (DHM) to describe perioperative inflammation by changes in biophysical cell properties of lymphocytes and monocytes. Blood samples from 25 patients were investigated prior to cardiac surgery and postoperatively at day 1, 3 and 6. Biophysical and morphological cell parameters accessible with DHM, such as cell volume, refractive index, dry mass, and cell shape related form factor, were acquired and compared to common flow cytometric blood cell markers of inflammation and selected routine laboratory parameters. In all examined patients, cardiac surgery induced an acute inflammatory response as indicated by changes in routine laboratory parameters and flow cytometric cell markers. DHM results were associated with routine laboratory and flow cytometric data and correlated with complications in the postoperative course. In a subgroup analysis, patients were classified according to the inflammation related C-reactive protein (CRP) level, treatment with epinephrine and the occurrence of postoperative complications. Patients with regular courses, without epinephrine treatment and with low CRP values showed a postoperative lymphocyte volume increase. In contrast, the group of patients with increased CRP levels indicated an even further enlarged lymphocyte volume, while for the groups of epinephrine treated patients and patients with complicative courses, no postoperative lymphocyte volume changes were detected. In summary, the study demonstrates the capability of DHM to describe biophysical cell parameters of perioperative lymphocytes and monocytes changes in cardiac surgery patients. The pattern of correlations between biophysical DHM data and laboratory parameters, flow cytometric cell markers, and the postoperative course exemplify DHM as a promising diagnostic tool for a characterization of inflammatory processes and course of disease.

[Perioperative management of the brain-dead organ donor : Anesthesia between ethics and evidence]. / Perioperatives Management der postmortalen Organspende : Anästhesie zwischen Ethik und Evidenz.

BACKGROUND: The number of organs donated after brain death in Germany is far lower than the demand. This underlines the importance of providing the brain-dead donor with optimal medical care throughout the donation process to decrease the risk of graft dysfunction. Several international guidelines and national recommendations guide the intensivists in organ-protective intensive care management of the brain-dead donor. OBJECTIVE: The anesthetist is a key member during organ retrieval procedures and plays a crucial role in physiological donor management; however, evidence-based recommendations for the perioperative anesthetic management, drug treatment strategies and target values are lacking. Anesthesia literature about donor management is scarce and predominantly composed of reviews of practice, with little exploration of the scientific foundations. The aim of this review is to guide the anesthetist in the organ-protective perioperative therapy. The pathophysiological changes in patients who progress to brain death are briefly summarized. The available evidence, guidelines and expert opinions regarding medical treatment strategies and therapeutic goals in organ-protective therapy are reviewed. The ethical and pathophysiological considerations regarding the performance of anesthesia during organ retrieval are discussed. METHODS: This review is based on a selective literature search in PubMed for publications regarding organ donation after brain death (keywords: "brain dead donor", "organ procurement", "organ protective therapy", "donor preconditioning", "perioperative donor management", "ethical considerations of brain dead donor"). International guidelines, national recommendations and expert opinions were given special consideration. RESULTS: Overall, the evidence for optimal perioperative organ-protective care of the brain-dead donor is limited. Most elements in the current recommendations and guidelines are based on pathophysiological reasoning, epidemiological observations or extrapolations from general organ-protective management strategies, and not on evidence from randomized controlled trials. National and international recommendations on treatment goals and drug therapy differ considerably in some aspects. The therapy concepts applied are very heterogeneous. Apart from medical challenges, the ethical circumstances are an additional burden for the entire treatment team. Whether anesthesia is reasonable during organ retrieval remains unclear. There is uncertainty about possible organ-protective effects of anesthetic drugs. Furthermore, ethical considerations raise the question of whether the determination of brain death and the use of anesthetic drugs during the procedure of organ retrieval are compatible with each other. CONCLUSION: Due to the lack of evidence, perioperative treatment should be guided by intensive care therapy strategies. The discussion about using anesthetic drugs during organ retrieval remains controversial. Pathophysiological considerations support the use of volatile anesthetics because of possible organ-protective effects. The use of neuromuscular blocking is justified to control any possible motor response resulting from spinal cord reflexes, whereas there is no evidence for a benefit from using opioids. Apart from that, it seems ethically problematic to anesthetise a brain-dead donor. Consequently, knowledge about the pathophysiological processes caused by brain death and about organ-protective therapy concepts are just as much a basic requirement as the consideration of ethical problems in organ donation after brain death. Only then are the caregivers able to do justice to both the organ recipient and the organ donor, as well as their relatives in this challenging situation.

In Response to Colloids Use in Asian ICU Patients: Do not Mix Oranges with Apples. Consider the Proven Concerns on Hydroxyethyl Starch Use in ICU patients.

How to cite this article: Ertmer C. In Response to Colloids Use in Asian ICU Patients: Do not Mix Oranges with Apples. Consider the Proven Concerns on Hydroxyethyl Starch Use in ICU Patients. Indian J Crit Care Med 2021;25(5):597.

Population pharmacokinetics of vancomycin in patients with external ventricular drain-associated ventriculitis.

BACKGROUND: To determine the distribution of vancomycin into the cerebrospinal fluid (CSF) in patients with external ventricular drain (EVD)-associated ventriculitis, the pharmacokinetics of vancomycin were evaluated and covariate relationships explored. METHODS: For the population pharmacokinetic model patients were recruited in a neurocritical care unit at the University Hospital of Muenster in the period between January 2014 and June 2015. All patients had a clinical evidence of EVD-associated ventriculitis. Population pharmacokinetic analysis of vancomycin was performed using NONMEM. RESULTS: A total of 184 blood and 133 CSF samples were collected from 29 patients. The final population pharmacokinetic model is a three-compartment model with linear elimination. Creatinine clearance (ClCr ) and CSF-lactate were detected as significant covariates, showing that the total vancomycin plasma clearance (Cl) depends on ClCr and furthermore the clearance (Cldif ) between the central and CSF compartment correlates with CSF lactate concentration. Based on the final model, the following values were estimated by NONMEM: Cl = 5.15 L/h, Q (intercompartmental clearance) = 3.31 L/h, Cldif  = 0.0031 L/h, Vcentral  = 42.1 L, VCSF  = 0.32 L and the value of Vperipheral was fixed to 86.2 L. With the developed pharmacokinetic model, area under the curve (AUC) values as well as CSF trough levels were simulated. CONCLUSION: Based on our analysis, the dosing of vancomycin should be referred to the degree of inflammation (derived from the CSF lactate concentration) and renal function (derived from ClCr ).

Long term follow-up of a simplified and less burdened pancreatic duct ligation model of exocrine pancreatic insufficiency in Goettingen Minipigs.

BACKGROUND: Pancreatic duct ligation in a minipig model leads to exocrine pancreatic insufficiency (EPI). This allows the study of digestive processes and pancreatic enzyme replacement therapies. However, detailed descriptions of the surgical procedure, perioperative management, a determination of exocrine pancreatic insufficiency are scarce in the literature. Data of the long-term health status of minipigs upon EPI induction are still not available. Therefore, the present study describes in detail an experimental approach to the induction of exocrine pancreatic insufficiency via pancreatic duct ligation in minipigs and the long term follow up of the animal's health state. METHODS: 14 Goettingen minipigs underwent pancreatic duct ligation via midline laparotomy for the induction of exocrine pancreatic insufficiency. Fecal fat content, fat absorption, chymotrypsin levels, body weight and blood vitamin and glucose levels were determined. RESULTS: Exocrine pancreatic insufficiency was successfully induced in 12 Goettingen minipigs. Two minipigs failed to develop exocrine insufficiency most likely due to undetected accessory pancreatic ducts. All animals tolerated the procedure very well and gained weight within 8 weeks after surgery without requiring pancreatic enzyme replacement therapy. The follow up for approx. 180 weeks showed a stable body weight and health state of the animals with normal blood glucose levels (Table 1). From approx. 130 weeks post pancreatic duct ligation, all animals were supplemented with pancreatic enzymes and vitamins resulting in blood concentrations almost within the reference range. CONCLUSIONS: Pancreatic duct ligation in minipigs is an excellent method of inducing exocrine pancreatic insufficiency. It is important to identify and ligate accessory pancreatic ducts since persistence of accessory ducts will lead to maintenance of exocrine pancreatic function. The EPI model caused no persistent side effects in the animals and has the potential to be used in long-term EPI studies with up to 100 weeks post-OP without supplementation with enzymes and vitamins.

Systolic-dicrotic notch pressure difference can identify tachycardic patients with septic shock at risk of cardiovascular decompensation following pharmacological heart rate reduction.

BACKGROUND: During sepsis, heart rate (HR) reduction could be a therapeutic target, but identification of responders (non-compensatory tachycardia) and non-responders (compensatory for 'fixed' stroke volume [SV]) is challenging. We tested the ability of the difference between systolic and dicrotic pressure (SDPdifference), which reflects the coupling between myocardial contractility and a given afterload, in discriminating the origin of tachycardia. METHODS: In this post hoc analysis of 45 patients with septic shock with persistent tachycardia, we characterised features of haemodynamic response focusing on SDPdifference, classifying patients according to variations in arterial dP/dtmax after 4 h of esmolol administration to maintain HR <95 beats min-1. A cut-off value of 0.9 mm Hg ms-1 was used for group allocation. RESULTS: After reducing HR, arterial dP/dtmax remained above the cut-off in 23 patients, whereas it decreased below the cut-off in 22 patients (from 0.99 [0.37] to 0.63 [0.16] mm Hg ms-1; mean [SD], P<0.001). At baseline, patients with decreased dP/dtmax after esmolol had lower SDPdifference than those with higher dP/dtmax (40 [19] vs 53 [16] mm Hg, respectively; P=0.01). The SDPdifference remained unchanged after esmolol in the higher dP/dtmax group (49 [16] mm Hg), whereas it decreased significantly in patients with lower dP/dtmax (29 [11] mm Hg; P<0.001). In the latter, the HR reduction resulted in a significant cardiac output reduction with unchanged SV, whereas in patients with higher dP/dtmax SV increased (from 48 [12] to 67 [14] ml; P<0.001) with maintained cardiac output. CONCLUSIONS: A decrease in SDPdifference could discriminate between compensatory and non-compensatory tachycardia, revealing a covert loss of myocardial contractility not detected by conventional echocardiographic parameters and deteriorating after HR reduction with esmolol. CLINICAL TRIAL REGISTRATION: NCT02188888.

Author Correction: Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study.

Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to time-consuming analysis and susceptibility to artifacts. We investigated the suitability of optical coherence tomography angiography (OCTA) for contactless evaluation of sublingual microcirculation. Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). OCTA images were analyzed with regard to flow density and perfused vessel density (PVDbyOCTA). IDF videos were analyzed following current recommendations. Flow density was automatically extracted from OCTA images (whole en face 48.9% [43.2; 54.5]; central ring 52.6% [43.6; 60.6]). PVDbyOCTA did not differ from the PVD calculated from IDF videos (PVDbyOCTA 18.6 mm/mm² [18.0; 21.7]) vs. PVDbyIDF 21.0 mm/mm² [17.5; 22.9]; p = 0.430). Analysis according to Bland-Altman revealed a mean bias of 0.95 mm/mm² (95% Confidence interval -1.34 to 3.25) between PVDbyOCTA and PVDbyIDF with limits of agreement of -5.34 to 7.24 mm/mm². This study is the first to demonstrate the suitability of OCTA for evaluating sublingual microcirculation. Comparison of the perfused vessel density between methods showed a plausible level of agreement.

A Prospective Observational Study of Rational Fluid Therapy in Asian Intensive Care Units: Another Puzzle Piece in Fluid Therapy.

INTRODUCTION: Fluid therapy in critically ill patients, especially timing and fluid choice, is controversial. Previous randomized trials produced conflicting results. This observational study evaluated the effect of colloid use on 90-day mortality and acute kidney injury (RIFLE F) within the Rational Fluid Therapy in Asia (RaFTA) registry in intensive care units. MATERIALS AND METHODS: RaFTA is a prospective, observational study in Asian intensive care unit (ICU) patients focusing on fluid therapy and related outcomes. Logistic regression was performed to identify risk factors for increased 90-day mortality and acute kidney injury (AKI). RESULTS: Twenty-four study centers joined the RaFTA registry and collected 3,187 patient data sets from November 2011 to September 2012. A follow-up was done 90 days after ICU admission. For 90-day mortality, significant risk factors in the overall population were sepsis at admission (OR 2.185 [1.799; 2.654], p < 0.001), cumulative fluid balance (OR 1.032 [1.018; 1.047], p < 0.001), and the use of vasopressors (OR 3.409 [2.694; 4.312], p < 0.001). The use of colloids was associated with a reduced risk of 90-day mortality (OR 0.655 [0.478; 0.900], p = 0.009). The initial colloid dose was not associated with an increased risk for AKI (OR 1.094 [0.754; 1.588], p = 0.635). CONCLUSION: RaFTA adds the important finding that colloid use was not associated with increased 90-day mortality or AKI after adjustment for baseline patient condition. CLINICAL SIGNIFICANCE: Early resuscitation with colloids showed potential mortality benefit in the present analysis. Elucidating these findings may be an approach for future research. HOW TO CITE THIS ARTICLE: Jacob M, Sahu S, Singh YP, Mehta Y, Yang K-Y, Kuo S-W, et al. A Prospective Observational Study of Rational Fluid Therapy in Asian Intensive Care Units: Another Puzzle Piece in Fluid Therapy. Indian J Crit Care Med 2020;24(11):1028-1036.

Resuscitation with Hydroxyethyl Starch Maintains Hemodynamic Coherence in Ovine Hemorrhagic Shock.

BACKGROUND: Fluid resuscitation in hemorrhagic shock aims to restore hemodynamics and repair altered microcirculation. Hemodynamic coherence is the concordant performance of macro- and microcirculation. The present study on fluid therapy in hemorrhagic shock hypothesized that the choice of fluid (0.9% sodium chloride [saline group] or balanced 6% hydroxyethyl starch 130/0.4 [hydroxyethyl starch group]) impacts on hemodynamic coherence. METHODS: After instrumentation, 10 sheep were bled up to 30 ml/kg body weight of blood stopping at a mean arterial pressure of 30 mmHg to establish hemorrhagic shock. To reestablish baseline mean arterial pressure, they received either saline or hydroxyethyl starch (each n = 5). Hemodynamic coherence was assessed by comparison of changes in mean arterial pressure and both perfused vessel density and microvascular flow index. RESULTS: Bleeding of 23 ml/kg blood [21; 30] (median [25th; 75th percentile]) in the saline group and 24 ml/kg [22; 25] (P = 0.916) in the hydroxyethyl starch group led to hemorrhagic shock. Fluid resuscitation reestablished baseline mean arterial pressure in all sheep of the hydroxyethyl starch group and in one sheep of the saline group. In the saline group 4,980 ml [3,312; 5,700] and in the hydroxyethyl starch group 610 ml [489; 615] of fluid were needed (P = 0.009). In hemorrhagic shock perfused vessel density (saline from 100% to 83% [49; 86]; hydroxyethyl starch from 100% to 74% [61; 80]) and microvascular flow index (saline from 3.1 [2.5; 3.3] to 2.0 [1.6; 2.3]; hydroxyethyl starch from 2.9 [2.9; 3.1] to 2.5 [2.3; 2.7]) decreased in both groups. After resuscitation both variables improved in the hydroxyethyl starch group (perfused vessel density: 125% [120; 147]; microvascular flow index: 3.4 [3.2; 3.5]), whereas in the saline group perfused vessel density further decreased (64% [62; 79]) and microvascular flow index increased less than in the hydroxyethyl starch group (2.7 [2.4; 2.8]; both P < 0.001 for saline vs. hydroxyethyl starch). CONCLUSIONS: Resuscitation with hydroxyethyl starch maintained coherence in hemorrhagic shock. In contrast, saline only improved macro- but not microcirculation. Hemodynamic coherence might be influenced by the choice of resuscitation fluid.

Association of sublingual microcirculation parameters and endothelial glycocalyx dimensions in resuscitated sepsis.

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.

[Optical coherence tomography angiography in intensive care medicine : A new field of application?] / Optische Kohärenztomographie-Angiographie in der Intensivmedizin : Ein neues Einsatzgebiet?

BACKGROUND: Many critically ill patients show a disturbance of the microcirculation, which is not yet regularly examined in the clinical routine; however, for treatment decisions and estimation of the prognosis it would be important to obtain detailed information about the microcirculation in critically ill patients. Optical coherence tomography angiography (OCTA) is a non-invasive, contact-free technique, which enables visualization of the blood flow in the retinal microcirculation within a few seconds. Therefore, it may have the potential to diagnose microcirculation disorders in critically ill patients. OBJECTIVE: The aims of the study were to assess the importance of the microcirculation in intensive care medicine, a comparison of the methods of video microscopy and OCTA and analysis of preclinical and clinical data on the use of OCTA in intensive care medicine. MATERIAL AND METHODS: A selective literature review and data analysis were carried out. RESULTS: A direct visualization of the microcirculation has been possible for many years with the technique of video microscopy but this has not become established in the clinical routine due to the susceptibility to interferences and a time-consuming manual analysis. The OCTA is a non-invasive and contact-free method for the visualization of retinal blood flow. First preclinical data in septic and hemorrhagic shock show good results of OCTA for analysis of the microcirculation. CONCLUSION: The non-invasive technique of OCTA is a promising measurement method to enable bedside analysis of the microcirculation in critically ill paients in the future; however, some technical limitations must still be overcome.