Prognostic value of capillary refill time in adult patients: a systematic review with meta-analysis.

PURPOSE: Acute circulatory failure leads to tissue hypoperfusion. Capillary refill time (CRT) has been widely studied, but its predictive value remains debated. We conducted a meta-analysis to assess the ability of CRT to predict death or adverse events in a context at risk or confirmed acute circulatory failure in adults. METHOD: MEDLINE, EMBASE, and Google scholar databases were screened for relevant studies. The pooled area under the ROC curve (AUC ROC), sensitivity, specificity, threshold, and diagnostic odds ratio using a random-effects model were determined. The primary analysis was the ability of abnormal CRT to predict death in patients with acute circulatory failure. Secondary analysis included the ability of CRT to predict death or adverse events in patients at risk or with confirmed acute circulatory failure, the comparison with lactate, and the identification of explanatory factors associated with better accuracy. RESULTS: A total of 60,656 patients in 23 studies were included. Concerning the primary analysis, the pooled AUC ROC of 13 studies was 0.66 (95%CI [0.59; 0.76]), and pooled sensitivity was 54% (95%CI [43; 64]). The pooled specificity was 72% (95%CI [55; 84]). The pooled diagnostic odds ratio was 3.4 (95%CI [1.4; 8.3]). Concerning the secondary analysis, the pooled AUC ROC of 23 studies was 0.69 (95%CI [0.65; 0.74]). The prognostic value of CRT compared to lactate was not significantly different. High-quality CRT was associated with a greater accuracy. CONCLUSION: CRT poorly predicted death and adverse events in patients at risk or established acute circulatory failure. Its accuracy is greater when high-quality CRT measurement is performed.

Reliability and reproducibility of the DICART device to assess capillary refill time: a bench and in-silico study.

Capillary refill time (CRT) is an important indicator of peripheral perfusion with a strong prognostic value, but it is sensitive to environmental factors and numerous measurement methods are reported in the litterature. DiCARTECH has developed a device that assesses CRT. We sought to investigate the robustness of the device and the reproducibility of the algorithm in a bench and in-silico study. We used the video acquired from a previous clinical study on healthy volunteers. For the bench study, the measurement process was performed by a robotic system piloted by a computer that analyzed 250 times nine previously acquired videos. For the in-silico study, we used 222 videos to test the algorithm's robustness. We created 30 videos from each video with a large blind spot and used the "color jitter" function to create a hundred videos from each video. In the bench study, the coefficient of variation was 11% (95%CI: 9-13). The correlation with human-measured CRT was good (R2 = 0.91, P < 0.001). In the in-silico study, for the blind spotted video, the coefficient of variation was 13% (95%CI: 10-17). For the color-jitter modified video the coefficient of variation was 62% (95%CI: 55-70). We confirmed the ability of the DiCART™ II device to perform multiple measurements without mechanical or electronic dysfunction. The precision and reproducibility of the algorithm are compatible with the assessment of clinical small changes in CRT.

Hemodynamic Effects of Awake Prone Positioning With COVID-19 Acute Respiratory Failure.

INTRODUCTION: Awake prone positioning (PP) reduces need for intubation for patients with COVID-19 with acute respiratory failure. We investigated the hemodynamic effects of awake PP in non-ventilated subjects with COVID-19 acute respiratory failure. METHODS: We conducted a single-center prospective cohort study. Adult hypoxemic subjects with COVID-19 not requiring invasive mechanical ventilation receiving at least one PP session were included. Hemodynamic assessment was done with transthoracic echocardiography before, during, and after a PP session. RESULTS: Twenty-six subjects were included. We observed a significant and reversible increase in cardiac index (CI) during PP compared to supine position (SP): 3.0 ± 0.8 L/min/m2 in PP, 2.5 ± 0.6 L/min/m2 before PP (SP1), and 2.6 ± 0.5 L/min/m2 after PP (SP2, P < .001). A significant improvement in right ventricular (RV) systolic function was also evidenced during PP: The RV fractional area change was 36 ± 10% in SP1, 46 ± 10% during PP, and 35 ± 8% in SP2 (P < .001). There was no significant difference in PaO2 /FIO2 and breathing frequency. CONCLUSION: CI and RV systolic function are improved by awake PP in non-ventilated subjects with COVID-19 with acute respiratory failure.

Central Versus Peripheral Arterial Pressure Monitoring in Patients Undergoing Cardiac Surgery: A Prospective Observational Study.

OBJECTIVE: The aortic-to-radial arterial pressure gradient is described during and after cardiopulmonary bypass (CPB), and can lead to underestimating arterial blood pressure. The authors hypothesized that central arterial pressure monitoring would be associated with lower norepinephrine requirements than radial arterial pressure monitoring during cardiac surgery. DESIGN: An observational prospective cohort with propensity score analysis. SETTING: At a tertiary academic hospital's operating room and intensive care unit (ICU). PARTICIPANTS: A total of 286 consecutive adult patients undergoing cardiac surgery with CPB (central group: 109; radial group: 177) were enrolled and analyzed. INTERVENTIONS: To explore the hemodynamic effect of the measurement site, the authors divided the cohort into 2 groups according to a femoral/axillary (central group) or radial (radial group) site of arterial pressure monitoring. MEASUREMENT AND MAIN RESULTS: The primary outcome was the intraoperative amount of norepinephrine administered. Secondary outcomes included norepinephrine-free hours and ICU-free hours at postoperative day 2 (POD2). A logistic model with propensity score analysis was built to predict central arterial pressure monitoring use. The authors compared demographic, hemodynamic, and outcomes data before and after adjustment. Central group patients had a higher European System for Cardiac Operative Risk Evaluation. (EuroSCORE) compared to the radial group-7.9 ± 14.0 versus 3.8 ± 7.0, p < 0.001. After adjustment, both groups had similar patient EuroSCORE and arterial blood pressure levels. Intraoperative norepinephrine dose regimens were 0.10 ± 0.10 µg/kg/min in the central group and 0.11 ± 0.11 µg/kg/min in the radial group (p = 0.519). Norepinephrine-free hours at POD2 were 38 ± 17 hours versus 33 ± 19 hours in central and radial groups, respectively (p = 0.034). The ICU-free hours at POD2 were greater in the central group: 18 ± 13 hours versus 13 ± 13 hours, p = 0.008. Adverse events were less frequent in the central group than in the radial group-67% versus 50%, p = 0.007. CONCLUSIONS: No differences in the norepinephrine dose regimen were found according to the arterial measurement site during cardiac surgery. However, norepinephrine use and length of stay in the ICU were shorter, and adverse events were decreased when central arterial pressure monitoring was used.

Advantages and limitations of noninvasive devices for cardiac output monitoring: a literature review.

PURPOSE OF REVIEW: Individualized hemodynamic optimization often requires cardiac output monitoring, mostly for goal-directed therapy in the operating room and fluid responsiveness assessment in the intensive care unit. Different technologies for noninvasive cardiac output determination have become available over the recent years. It is therefore crucial for care providers to be made aware of the advantages and limitations of those different devices for an appropriate use at the bedside. RECENT FINDINGS: Nowadays, different noninvasive technologies exist, each with their advantages and limitations, but none are considered interchangeable with bolus thermodilution. Different clinical studies however, emphasize that the trending ability of such devices allows to guide decisions from care providers, and that their use may be associated with improved prognosis, especially in the operating room. Recent studies have also reported their potential use for hemodynamic optimization in specific populations. SUMMARY: Noninvasive cardiac output monitoring may have a clinical impact on patient outcomes. Further studies are required to evaluate their clinical relevance, notably in the intensive care unit. Noninvasive monitoring opens up the possibility for hemodynamic optimization in specific or low-risk populations, the benefit of which remains to be assessed.

Bioelectrical impedance analysis during deresuscitation: correlation and agreement with cumulative fluid balance in ICU patients.

Bioelectrical impedance analysis (BIA) is a promising tool to evaluate the body composition of critically-ill patients. The present study aimed to assess its value as a fluid management monitoring tool during standardized deresuscitation strategy. A historical cohort of critically-ill adult patients with fluid overload and continuous renal replacement therapy was used to explore both relationship and agreement between changes in cumulative fluid balance and BIA-derived hydration variables within the 5 days following initiation of deresuscitation strategy using net ultrafiltration. Correlations were described using Spearman's rank correlation coefficient, and agreement using Bland-Altman analysis for repeated measurements. Sixty-one couples of fluid shift measurements from 30 patients were analyzed. The deresuscitation strategy induced a negative mean (± SD) cumulative fluid balance (- 4.2 ± 3.8 L) and a significant decrease in extra- and intracellular water (P < 0.001). Decreases in extra- and intracellular water were independent of weight variations inputted in the BIA device. Total body water (rho = 0.63), extracellular water (rho = 0.68), and intracellular water (rho = 0.67) were significantly correlated with cumulative fluid balance (all P values < 0.001). The limits of agreement did not allow interchangeability for a delta of 2L between cumulative fluid balance and BIA-derived hydration variables (P > 0.05). BIA hydration-derived variables are significantly correlated with cumulative fluid balance but the large limits of agreements exclude interchangeability of the measures.

Refilling and preload dependence failed to predict cardiac index decrease during fluid removal with continuous renal replacement therapy.

BACKGROUND: Fluid removal can reduce the burden of fluid overload after initial resuscitation. According to the Frank-Starling model, iatrogenic hypovolemia should induce a decrease in cardiac index. We hypothesized that inadequate refilling detected by haemoconcentration during fluid removal or an increase in cardiac index (CI) during passive leg raising (PLR) could predict CI decrease during mechanical fluid removal with continuous renal replacement therapy (CRRT). METHODS: We conducted a single-centre prospective diagnostic accuracy study. The primary objective was to investigate the diagnostic performance of plasma protein concentration variations in detecting a CI decrease ≥ 12% during mechanical fluid removal. Secondary objective was to assess other predictive factors of CI change. The attending physician prescribed a fluid removal challenge consisting of a mechanical fluid removal challenge of 500 mL for one hour. Plasma protein concentration, haemoglobin level, PLR and transpulmonary thermodilution were done before and after the fluid removal challenge. RESULTS: We included 69 adult patients between December 2016 and April 2020. Sixteen patients had a significant CI decrease (23% [95% CI 14-35]). Haemoconcentration and PLR before fluid removal challenge or CI trending failed to predict CI decrease. CONCLUSION: Haemoconcentration variables, preload dependence status and CI trending failed to predict CI decrease during fluid removal challenge.

Perfusion-based deresuscitation during continuous renal replacement therapy: A before-after pilot study (The early dry Cohort).

BACKGROUND: Active fluid removal has been suggested to improve prognosis following the resolution of acute circulatory failure. We have implemented a routine care protocol to guide fluid removal during continuous renal replacement therapy (CRRT). We designed a before-after pilot study to evaluate the impact of this deresuscitation strategy on the fluid balance. METHODS: Consecutive ICU patients suffering from fluid overload and undergoing CRRT for acute kidney injury underwent a perfusion-based deresuscitation protocol combining a restrictive intake, net ultrafiltration (UFnet) of 2 mL/kg/h, and monitoring of perfusion (early dry group, N = 42) and were compared to a historical group managed according to usual practices (control group, N = 45). The primary outcome was the cumulative fluid balance at day 5 or at discharge. RESULTS: Adjusted cumulative fluid balance was significantly lower in the early dry group (median [IQR]: -7784 [-11,833 to -2933] mL) compared to the control group (-3492 [-9935 to -1736] mL; p = 0.04). The difference was mainly driven by a greater daily UFnet (31 [22-46] mL/kg/day vs. 24 [15-32] mL/kg/day; p = 0.01). There was no significant difference between both groups regarding hemodynamic tolerance. CONCLUSION: Our perfusion-based deresuscitation protocol achieved a greater negative cumulative fluid balance compared to standard practices and was hemodynamically well tolerated.

Capillary refill time for the management of acute circulatory failure: a survey among pediatric and adult intensivists.

INTRODUCTION: Recent studies have shown the prognostic value of capillary refill time (CRT) and suggested that resuscitation management guided by CRT may reduce morbidity and mortality in patients with septic shock. However, little is known about the current use of CRT in routine clinical practice. This study aimed to assess the modalities of CRT use among French adult and pediatric intensivists. METHODS: A cross-sectional survey exploring CRT practices in acute circulatory failure was performed. The targeted population was French adult and pediatric intensivists (SFAR and GFRUP networks). An individual invitation letter including a survey of 32 questions was emailed twice. Descriptive and analytical statistics were performed. RESULTS: Among the 6071 physicians who received the letter, 418 (7%) completed the survey. Among all respondents, 82% reported using CRT in routine clinical practice, mainly to diagnose acute circulatory failure, but 45% did not think CRT had any prognostic value. Perfusion goal-directed therapy based on CRT was viewed as likely to improve patient outcome by 37% of respondents. The measurement of CRT was not standardized as the use of a chronometer was rare (3%) and the average of multiple measurements rarely performed (46%). Compared to adult intensivists, pediatric intensivists used CRT more frequently (99% versus 76%) and were more confident in its diagnostic value and its ability to guide treatment. CONCLUSION: CRT measurement is widely used by intensivists in patients with acute circulatory failure but most often in a non-standardized way. This may lead to a misunderstanding of CRT reliability and clinical usefulness.

Prediction of intraoperative hypotension from the linear extrapolation of mean arterial pressure.

BACKGROUND: Hypotension prediction index (HPI) software is a proprietary machine learning-based algorithm used to predict intraoperative hypotension (IOH). HPI has shown superiority in predicting IOH when compared to the predictive value of changes in mean arterial pressure (ΔMAP) alone. However, the predictive value of ΔMAP alone, with no reference to the absolute level of MAP, is counterintuitive and poor at predicting IOH. A simple linear extrapolation of mean arterial pressure (LepMAP) is closer to the clinical approach. OBJECTIVES: Our primary objective was to investigate whether LepMAP better predicts IOH than ΔMAP alone. DESIGN: Retrospective diagnostic accuracy study. SETTING: Two tertiary University Hospitals between May 2019 and December 2019. PATIENTS: A total of 83 adult patients undergoing high risk non-cardiac surgery. DATA SOURCES: Arterial pressure data were automatically extracted from the anaesthesia data collection software (one value per minute). IOH was defined as MAP < 65 mmHg. ANALYSIS: Correlations for repeated measurements and the area under the curve (AUC) from receiver operating characteristics (ROC) were determined for the ability of LepMAP and ΔMAP to predict IOH at 1, 2 and 5 min before its occurrence (A-analysis, using the whole dataset). Data were also analysed after exclusion of MAP values between 65 and 75 mmHg (B-analysis). RESULTS: A total of 24 318 segments of ten minutes duration were analysed. In the A-analysis, ROC AUCs to predict IOH at 1, 2 and 5 min before its occurrence by LepMAP were 0.87 (95% confidence interval, CI, 0.86 to 0.88), 0.81 (95% CI, 0.79 to 0.83) and 0.69 (95% CI, 0.66 to 0.71) and for ΔMAP alone 0.59 (95% CI, 0.57 to 0.62), 0.61 (95% CI, 0.59 to 0.64), 0.57 (95% CI, 0.54 to 0.69), respectively. In the B analysis for LepMAP these were 0.97 (95% CI, 0.9 to 0.98), 0.93 (95% CI, 0.92 to 0.95) and 0.86 (95% CI, 0.84 to 0.88), respectively, and for ΔMAP alone 0.59 (95% CI, 0.53 to 0.58), 0.56 (95% CI, 0.54 to 0.59), 0.54 (95% CI, 0.51 to 0.57), respectively. LepMAP ROC AUCs were significantly higher than ΔMAP ROC AUCs in all cases. CONCLUSIONS: LepMAP provides reliable real-time and continuous prediction of IOH 1 and 2 min before its occurrence. LepMAP offers better discrimination than ΔMAP at 1, 2 and 5 min before its occurrence. Future studies evaluating machine learning algorithms to predict IOH should be compared with LepMAP rather than ΔMAP.

Hemodynamic effects of extended prone position sessions in ARDS.

BACKGROUND: Hemodynamic response to prone position (PP) has never been studied in a large series of patients with acute respiratory distress syndrome (ARDS). The primary aim of this study was to estimate the rate of PP sessions associated with cardiac index improvement. Secondary objective was to describe hemodynamic response to PP and during the shift from PP to supine position. METHODS: The study was a single-center retrospective observational study, performed on ARDS patients, undergoing at least one PP session under monitoring by transpulmonary thermodilution. PP sessions performed more than 10 days after ARDS onset, or with any missing cardiac index measurements before (T1), at the end (T3), and after the PP session (T4) were excluded. Changes in hemodynamic parameters during PP were tested after statistical adjustment for volume of fluid challenges, vasopressor and dobutamine dose at each time point to take into account therapeutic changes during PP sessions. RESULTS: In total, 107 patients fulfilled the inclusion criteria, totalizing 197 PP sessions. Changes in cardiac index between T1 and T2 (early response to PP) and between T1 and T3 (late response to PP) were significantly correlated (R2 = 0.42, p < 0.001) with a concordance rate amounting to 85%. Cardiac index increased significantly between T1 and T3 in 49 sessions (25% [95% confidence interval (CI95%) 18-32%]), decreased significantly in 46 (23% [CI95% 16-31%]), and remained stable in 102 (52% [CI95% 45-59%]). Global end-diastolic volume index (GEDVI) increased slightly but significantly from 719 ± 193 mL m-2 at T1 to 757 ± 209 mL m-2 at T3 and returned to baseline values at T4. Cardiac index and oxygen delivery decreased slightly but significantly from T3 to T4, without detectable increase in lactate level. Patients who increased their cardiac index during PP had significantly lower CI, GEDVI, global ejection fraction at T1, and received significantly more fluids than patients who did not. CONCLUSION: PP is associated with an increase in cardiac index in 18% to 32% of all PP sessions and a sustained increase in GEDVI reversible after return to supine position. Return from prone to supine position is associated with a slight hemodynamic impairment.