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.

Lower Limb Ischemia in Surgical Femoral Veno-Arterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: To analyze the incidence, clinical impact on survival, and risk factors of lower limb ischemia (LLI) of surgical peripheral femoral venoarterial extracorporeal membrane oxygenation (VA ECMO) in the current era. DESIGN: A retrospective analysis of the authors' institutional database of VA ECMO was performed. Patients were divided into 2 groups according to the occurrence of LLI. The primary endpoint was survival to hospital discharge. Risk factors of LLI were searched with multivariate analyses. SETTING: University hospital. PARTICIPANTS: Adult patients receiving peripheral VA ECMO for refractory cardiogenic shock and cardiac arrest. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: From January 2018 to December 2021, 188 patients (mean age: 52.0 ± 14.1 years; 63.8% male, 36.2% female) received peripheral VA ECMO. Male sex was more prevalent in the group without LLI (65.9% v 33.3%; p = 0.031). Twelve (6.4%) patients developed LLI during VA ECMO support (n = 6) or after VA ECMO removal (n = 6). Survival to hospital discharge was not statistically different between patients with and without LLI (50.0% v 48.3%; p = 0.571). Female sex patients were at increased risk for LLI (odds ratio 4.38, 95% CI 1.21-15.81; p = 0.024). CONCLUSIONS: Peripheral femoral VA ECMO through a surgical approach is associated with a low LLI rate, which does not increase the risk of in-hospital mortality. The female sex is an independent risk factor for LLI.

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.

Elaboration of a French version of the Duke Activity Status Index questionnaire and performance to predict functional capacity.

BACKGROUND: Guidelines recommend detecting poor functional capacity (VO2max < 14 ml.kg-1.min-1) to assess preoperative cardiac risk. This screening is performed via a cardiopulmonary exercise test (CPET), the self-reported inability to climb two flights of stairs, or the use of the Duke Activity Status Index (DASI) questionnaire, which has shown a significant correlation with VO2max and postoperative outcomes. The objectives of the present study were: 1) to create a French version of the DASI questionnaire (FDASI); 2) to assess its diagnostic performance in predicting functional capacity. METHODS: Consecutive adult patients undergoing CPET for medical or preoperative evaluation were prospectively included between May 2020 and March 2021. All patients were asked to complete FDASI as a self-questionnaire and report their inability to climb two flights of stairs. RESULTS: 122 patients were included. Test-retest reliability was 0.88 and 23 (19%) patients experienced a VO2max < 14 ml.kg-1.min-1. There was a significant positive relationship between FDASI and VO2max: r2 = 0.32; p < 0.001. ROCAUC was 0.81 [95%CI: 0.73-0.89]. The best FDASI score threshold was 36 points, leading to sensitivity and specificity values of 87% [74-100] and 68% [56-79], respectively. Besides, sensitivity and specificity were 35% [17-56] and 92% [86-97] for the self-reported inability to climb two flights of stairs. CONCLUSION: A FDASI score of 36 represents a reliable threshold the clinicians could routinely use to identify patients with a VO2max < 14 ml.kg-1.min-1. FDASI could advantageously replace the self-reported inability to climb two flights of stairs.

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.

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.

Veno-arterial extracorporeal membrane oxygenation for drug intoxications: A single center, 14-year experience.

BACKGROUND AND AIM OF THE STUDY: Acute cardiovascular failure remains a leading cause of death in severe poisonings. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been increasingly used as a rescue therapeutic option for those cases refractory to optimal conventional treatment. We sought to evaluate the outcomes after VA-ECMO used for drug intoxications in a single-center experience. METHODS: We performed an observational analysis of our prospective institutional database. The primary endpoint was survival to hospital discharge. RESULTS: Between January 2007 and December 2020, 32 patients (mean age: 45.4 ± 15.8 years; 62.5% female) received VA-ECMO for drug intoxication-induced refractory cardiogenic shock (n = 25) or cardiac arrest (n = 7). Seven (21.8%) patients developed lower limb ischemia during VA-ECMO support. Twenty-six (81.2%) patients were successfully weaned after a mean VA-ECMO support of 2.9 ± 1.3 days. One (3.1%) patient died after VA-ECMO weaning for multiorgan failure and survival to hospital discharge was 78.1% (n = 25). In-hospital survivors were discharged from hospital with a good neurological status. Survival to hospital discharge was not statistically different according to sex (male = 75.0% vs. female = 80.0%; p = .535), type of intoxication (single drug = 81.8% vs. multiple drugs = 76.1%; p = .544) and location of VA-ECMO implantation (within our center = 75% vs. peripheral hospital using our Mobile Unit of Mechanical Circulatory Support = 100%; p = .352). Survival to hospital discharge was significantly lower in patients receiving VA-ECMO during on-going cardiopulmonary resuscitation (42.8% vs. 88.0%; p = .026). CONCLUSIONS: VA-ECMO appears to be a feasible therapeutic option with a satisfactory survival rate and acceptable complications rate in poisonings complicated by refractory cardiogenic shock or cardiac arrest.

Preload Dependence Fails to Predict Hemodynamic Instability During a Fluid Removal Challenge in Children.

OBJECTIVES: Fluid overload increases morbidity and mortality in PICU patients. Active fluid removal improves the prognosis but may worsen organ dysfunction. Preload dependence in adults does predict hemodynamic instability induced by a fluid removal challenge (FRC). We sought to investigate the diagnostic accuracy of dynamic and static markers of preload in predicting hemodynamic instability and reduction of stroke volume during an FRC in children. We followed the Standards for Reporting of Diagnostic Accuracy statement to design conduct and report this study. DESIGN: Prospective noninterventional cohort study. SETTINGS: From June 2017 to April 2019 in a pediatric cardiac ICU in a tertiary hospital. PATIENTS: Patients 8 years old or younger, with symptoms of fluid overload after cardiac surgery, were studied. INTERVENTIONS: We confirmed preload dependence by echocardiography before and during a calibrated abdominal compression test. We then performed a challenge to remove 10-mL/kg fluid in less than 120 minutes with an infusion of diuretics. Hemodynamic instability was defined as a decrease of 10% of mean arterial pressure. MEASUREMENT AND MAIN RESULTS: We compared patients showing hemodynamic instability with patients remaining stable, and we built receiver operative characteristic (ROC) curves. Among 58 patients studied, 10 showed hemodynamic instability. The area under the ROC curve was 0.55 for the preload dependence test (95% CI, 0.34-0.75). Using a threshold of 10% increase in stroke volume index (SVi) during calibrated abdominal compression, the specificity was 0.30 (95% CI, 0.00-0.60) and the sensitivity was 0.77 (95% CI, 0.65-0.88). Mean arterial pressure variation and SVi variation were not correlated during fluid removal; r = 0.19; 95% CI -0.07 to 0.43; p = 0.139. CONCLUSIONS: Preload dependence is not accurate to predict hemodynamic instability during an FRC. Our data do not support a reduction in intravascular volume being mainly responsible for the reduction in arterial pressure during an FRC in children.

Effects of methylene blue on microcirculatory alterations following cardiac surgery: A prospective cohort study.

BACKGROUND: Methylene blue is used as rescue therapy to treat catecholamine-refractory vasoplegic syndrome after cardiac surgery. However, its microcirculatory effects remain poorly documented. OBJECTIVE: We aimed to study microcirculatory abnormalities in refractory vasoplegic syndrome following cardiac surgery with cardiopulmonary bypass and assess the effects of methylene blue. DESIGN: A prospective open-label cohort study. SETTING: 20-Bed ICU of a tertiary care hospital. PATIENTS: 25 Adult patients receiving 1.5 mg kg-1 of methylene blue intravenously for refractory vasoplegic syndrome (defined as norepinephrine requirement more than 0.5 µg kg-1 min-1) to maintain mean arterial pressure (MAP) more than 65 mmHg and cardiac index (CI) more than 2.0 l min-1 m-2. MAIN OUTCOME MEASURES: Complete haemodynamic set of measurements at baseline and 1 h after the administration of methylene blue. Sublingual microcirculation was investigated by sidestream dark field imaging to obtain microvascular flow index (MFI), total vessel density, perfused vessel density and heterogeneity index. Microvascular reactivity was assessed by peripheral near-infrared (IR) spectroscopy combined with a vascular occlusion test. We also performed a standardised measurement of capillary refill time. RESULTS: Despite normalised CI (2.6 [2.0 to 3.8] l min-1 m-2) and MAP (66 [55 to 76] mmHg), patients with refractory vasoplegic syndrome showed severe microcirculatory alterations (MFI < 2.6). After methylene blue infusion, MFI significantly increased from 2.0 [0.1 to 2.5] to 2.2 [0.2 to 2.8] (P = 0.008), as did total vessel density from 13.5 [8.3 to 18.5] to 14.9 [10.1 to 14.7] mm mm-2 (P = 0.02) and perfused vessel density density from 7.4 [0.1 to 11.5] to 9.1 [0 to 20.1] mm mm-2 (P = 0.02), but with wide individual variation. Microvascular reactivity assessed by tissue oxygen resaturation speed also increased from 0.5 [0.1 to 1.8] to 0.7 [0.1 to 2.7]% s-1 (P = 0.002). Capillary refill time remained unchanged throughout the study. CONCLUSION: In refractory vasoplegic syndrome following cardiac surgery, we found microcirculatory alterations despite normalised CI and MAP. The administration of methylene blue could improve microvascular perfusion and reactivity, and partially restore the loss of haemodynamic coherence. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04250389.

Eco-audit of conventional heart surgery procedures.

OBJECTIVES: Healthcare systems have a significant environmental impact and, thus, indirectly affect public health. In order to improve current practices, a better understanding of the actual environmental impact generated by surgical procedures is necessary. METHODS: An eco-audit methodology was carried out to assess the greenhouse gas emissions arising from conventional isolated cardiac surgery procedures. This inquiry took into account 3 workstations (the surgical, the anaesthesia and the cardiopulmonary bypass workstations). All wastes were analysed including the disposable medical products, pharmaceuticals and energy consumption during such surgeries. RESULTS: Twenty-eight cardiac surgeries were analysed out of a 4-week study period. The mean emissions during a single cardiac surgery was 124.3 kg of carbon dioxide equivalent (CO2-e). Eighty-nine per cent of the total emissions was related to the use of disposable medical products. The environmental impact of pharmaceuticals used at anaesthesia workstations was 12.4 kg of CO2-e (10% of total greenhouse gas emission), with 11.1 kg of CO2-e resulting from the use of halogenated gas. Direct electrical consumption resulted in 4.0 kg of CO2-e per surgery (3% of all emission), including lighting and air conditioning. CONCLUSIONS: Conventional isolated cardiac procedures yield the global warming equivalent of a 1080 km plane ride for a single passenger. The environmental impact of such life-saving interventions, therefore, must be put in perspective alongside pollution induced by 'non-indispensable' human activities. However, numerous initiatives at the local and individual level as well as at a larger systemic and countrywide scale appear to provide accessible pathways to meaningfully reduce greenhouse gas emissions during cardiac surgery.