Early hyperoxia and 28-day mortality in patients on venoarterial ECMO support for refractory cardiogenic shock: a bicenter retrospective propensity score-weighted analysis

BACKGROUND

The mortality rate for a patient with a refractory cardiogenic shock on venoarterial (VA) extracorporeal membrane oxygenation (ECMO) remains high, and hyperoxia might worsen this prognosis. The objective of the present study was to evaluate the association between hyperoxia and 28-day mortality in this setting.

METHODS

We conducted a retrospective bicenter study in two French academic centers. The study population comprised adult patients admitted for refractory cardiogenic shock. The following arterial partial pressure of oxygen (PaO2) variables were recorded for 48 h following admission: the absolute peak PaO2 (the single highest value measured during the 48 h), the mean daily peak PaO2 (the mean of each day's peak values), the overall mean PaO2 (the mean of all values over 48 h), and the severity of hyperoxia (mild: PaO2 < 200 mmHg, moderate: PaO2 = 200-299 mmHg, severe: PaO2 ≥ 300 mmHg). The main outcome was the 28-day all-cause mortality. Inverse probability weighting (IPW) derived from propensity scores was used to reduce imbalances in baseline characteristics.

RESULTS

From January 2013 to January 2020, 430 patients were included and assessed. The 28-day mortality rate was 43%. The mean daily peak, absolute peak, and overall mean PaO2 values were significantly higher in non-survivors than in survivors. In a multivariate logistic regression analysis, the mean daily peak PaO2, absolute peak PaO2, and overall mean PaO2 were independent predictors of 28-day mortality (adjusted odds ratio [95% confidence interval per 10 mmHg increment: 2.65 [1.79-6.07], 2.36 [1.67-4.82], and 2.85 [1.12-7.37], respectively). After IPW, high level of oxygen remained significantly associated with 28-day mortality (OR = 1.41 [1.01-2.08]; P = 0.041).

CONCLUSIONS

High oxygen levels were associated with 28-day mortality in patients on VA-ECMO support for refractory cardiogenic shock. Our results confirm the need for large randomized controlled trials on this topic.

Can yeast isolation be predicted in complicated secondary non-postoperative intra-abdominal infections?

INTRODUCTION

The aim of this study was to create a predictive score for yeast isolation in patients with complicated non-postoperative intra-abdominal infections (CNPIAI) and to evaluate the impact of yeast isolation on outcome.

METHODS

All patients with a CNPIAI undergoing emergency surgery over a three-year period were included in the retrospective cohort (RC, n = 290). Patients with a yeast-positive peritoneal fluid culture (YP) were compared with patients with a yeast-negative culture (YN). Multivariate logistic regression was used to identify factors independently associated with yeast isolation and a predictive score was built. The score's performance was then established in the prospective cohort (PC, n = 152) over an 18-month period. Outcome of the whole cohort was evaluated and independent risks factors of mortality searched.

RESULTS

In the RC, 39 patients (13.4%) were YP. Four factors were independently associated with the YP group: length of stay before surgery ≥48 h (odds ratio (OR) (95% confidence interval (CI)) = 3.1 (1.4 to 6.9), P = 0.004, 1 point), per-operative cardiovascular failure (2.4 (1.1 to 5.8), P = 0.04, 1 point), generalized peritonitis (6.8 (2.7 to 16.7), P <0.001, 2 points) and upper gastrointestinal tract perforation (2.5 (1.2 to 5.6), P = 0.02, 1 point). In the PC, the area under the curve (95%CI) of the predictive score's receiver operating characteristic curve was 0.79 (0.72 to 0.86). For predicting an intra-abdominal candidiasis (IAC), a score ≥3 had a sensitivity of 0.60, a specificity of 0.84, a positive predictive value of 0.49 and a negative predictive value of 0.89. Furthermore, yeast isolation was associated with worse outcome and independently associated with mortality in the whole cohort (OR = 2.15; 95%CI (1.03 to 4.46), P = 0.04).

CONCLUSIONS

The new predictive score can be used to rule out intra-abdominal candidiasis and thus avoid the initiation of antifungal treatment. It is suited to less severe infections than previously published scores. IAC is associated independently with an increased mortality in this population.

Arterial pulse pressure variation suitability in critical care: A French national survey

OBJECTIVE

Arterial pulse pressure variation (PPV) has been used as an accurate index to predict fluid responsiveness. However, many confounding factors have been recently described. The aims of this study were to assess the conditions of applicability of PPV in intensive care units (ICU).

STUDY DESIGN

A one-day French national survey.

PATIENTS AND METHODS

A form assessing the suitability of PPV was completed by practitioners for each critically-ill patient included on a set day.

RESULTS

Four hundred and sixty-five patients were included in 36 ICUs. A regular sinus rhythm was noted in 408 (88%) patients and the presence of an arterial line in 324 (70%) patients. One hundred and twenty-seven (27%) patients were mechanically ventilated without spontaneous breathing. Only six patients (1.3%) had no confounding factors modifying the threshold value of the PPV.

CONCLUSION

The incidence of ICU patients in whom PPV was suitable and without confounding factors were respectively 18% and 1.3% in this one-day French national survey.

Dynamic arterial elastance measured by uncalibrated pulse contour analysis predicts arterial-pressure response to a decrease in norepinephrine

BACKGROUND

Dynamic arterial elastance (Eadyn) has been proposed as an indicator of vascular tone that predicts the decrease in arterial pressure in response to changes in norepinephrine (NE). The purpose of this study was to determine whether Eadyn measured by uncalibrated pulse contour analysis (UPCA) can predict a decrease in arterial pressure when the NE dosage is decreased.

METHODS

We conducted a prospective study in a university hospital intensive care unit. Patients with vasoplegic syndrome for whom the intensive care physician planned to decrease the NE dosage were included. Haemodynamic and UPCA (VolumeView and FloTrac; Edwards Lifesciences, Irvine, CA, USA) values were obtained before and after decreasing the NE dosage. Responders were defined by a >10% decrease in mean arterial pressure (MAP).

RESULTS

Of 35 patients included, 11 (31%) were pressure responders with a median decrease of 13%. Eadyn was correlated to systolic arterial pressure (SAP) (r=0.255; P=0.033), diastolic arterial pressure (r=0.271; P=0.024), MAP (r=0.310; P=0.009), heart rate (r=0.543; P=0.0001), and transthoracic echography cardiac output (r=0.264; P=0.024). Baseline Eadyn was correlated with MAP changes (r=0.394; P=0.019) and SAP changes (r=0.431; P=0.009). Eadyn predicted the decrease in arterial pressure with an area under the receiver-operating-characteristic curve of 0.84 (95% confidence interval: 0.70-0.97). The best cut-off was 0.90.

CONCLUSIONS

The present study confirms the ability of Eadyn measured by UPCA to predict an arterial pressure response to a decrease in NE. Eadyn may constitute an easy-to-use functional approach to arterial tone assessment regardless of the monitor used to measure its determinant.

CLINICAL TRIAL REGISTRATION

DRCIT95.

Association between acute kidney injury and norepinephrine use following cardiac surgery: a retrospective propensity score-weighted analysis

BACKGROUND

Excess exposure to norepinephrine can compromise microcirculation and organ function. We aimed to assess the association between norepinephrine exposure and acute kidney injury (AKI) and intensive care unit (ICU) mortality after cardiac surgery.

METHODS

This retrospective observational study included adult patients who underwent cardiac surgery under cardiopulmonary bypass from January 1, 2008, to December 31, 2017, at the Amiens University Hospital in France. The primary exposure variable was postoperative norepinephrine during the ICU stay and the primary endpoint was the presence of AKI. The secondary endpoint was in-ICU mortality. As the cohort was nonrandom, inverse probability weighting (IPW) derived from propensity scores was used to reduce imbalances in the pre- and intra-operative characteristics.

RESULTS

Among a population of 5053 patients, 1605 (32%) were exposed to norepinephrine following cardiac surgery. Before weighting, the prevalence of AKI was 25% and ICU mortality 10% for patients exposed to norepinephrine. Exposure to norepinephrine was estimated to be significantly associated with AKI by a factor of 1.95 (95% confidence interval, 1.63-2.34%; P < 0.001) in the IPW cohort and with in-ICU mortality by a factor of 1.54 (95% confidence interval, 1.19-1.99%; P < 0.001).

CONCLUSION

Norepinephrine was associated with AKI and in-ICU mortality following cardiac surgery. While these results discourage norepinephrine use for vasoplegic syndrome in cardiac surgery, prospective investigations are needed to substantiate findings and to suggest alternative strategies for organ protection.

Passive leg raising-induced changes in pulse pressure variation to assess fluid responsiveness in mechanically ventilated patients: a multicentre prospective observational study

BACKGROUND

Passive leg raising-induced changes in cardiac index can be used to predict fluid responsiveness. We investigated whether passive leg raising-induced changes in pulse pressure variation (ΔPPVPLR) can also predict fluid responsiveness in mechanically ventilated patients.

METHODS

In this multicentre prospective observational study, we included 270 critically ill patients on mechanical ventilation in whom volume expansion was indicated because of acute circulatory failure. We did not include patients with cardiac arrythmias. Cardiac index and PPV were measured before/during a passive leg raising test and before/after volume expansion. A volume expansion-induced increase in cardiac index of >15% defined fluid responsiveness. To investigate whether ΔPPVPLR can predict fluid responsiveness, we determined areas under the receiver operating characteristic curves (AUROCs) and grey zones for relative and absolute ΔPPVPLR.

RESULTS

Of the 270 patients, 238 (88%) were on controlled mechanical ventilation with no spontaneous breathing activity and 32 (12%) were on pressure support ventilation. The median tidal volume was 7.1 (inter-quartile range [IQR], 6.6-7.6) ml kg-1 ideal body weight. One hundred sixty-four patients (61%) were fluid responders. Relative and absolute ΔPPVPLR predicted fluid responsiveness with an AUROC of 0.92 (95% confidence interval [95% CI], 0.88-0.95; P<0.001) each. The grey zone for relative and absolute ΔPPVPLR included 4.8% and 22.6% of patients, respectively. These results were not affected by ventilatory mode and baseline characteristics (type of shock, centre, vasoactive treatment).

CONCLUSIONS

Passive leg raising-induced changes in pulse pressure variation accurately predict fluid responsiveness with a small grey zone in critically ill patients on mechanical ventilation.

CLINICAL TRIAL REGISTRATION

NCT03225378.

Automated left atrial strain analysis for predicting atrial fibrillation in severe COVID-19 pneumonia: a prospective study

BACKGROUND

Atrial fibrillation (AF) is the most documented arrhythmia in COVID-19 pneumonia. Left atrial (LA) strain (LAS) analysis, a marker of LA contractility, have been associated with the development of AF in several clinical situations. We aimed to assess the diagnostic ability of LA strain parameters to predict AF in patients with severe hypoxemic COVID-19 pneumonia. We conducted a prospective single center study in Amiens University Hospital intensive care unit (ICU) (France). Adult patients with severe or critical COVID-19 pneumonia according to the World Health Organization definition and in sinus rhythm were included. Transthoracic echocardiography was performed within 48 h of ICU admission. LA strain analysis was performed by an automated software. The following LA strain parameters were recorded: LA strain during reservoir phase (LASr), LA strain during conduit phase (LAScd) and LA strain during contraction phase (LASct). The primary endpoint was the occurrence of AF during ICU stay.

RESULTS

From March 2020 to February of 2021, 79 patients were included. Sixteen patients (20%) developed AF in ICU. Patients of the AF group were significantly older with a higher SAPS II score than those without AF. LAScd and LASr were significantly more impaired in the AF group compared to the other group (- 8.1 [- 6.3; - 10.9] vs. - 17.2 [- 5.0; - 10.2] %; P < 0.001 and 20.2 [12.3;27.3] % vs. 30.5 [23.8;36.2] %; P = 0.002, respectively), while LASct did not significantly differ between groups (p = 0.31). In a multivariate model, LAScd and SOFA cv were significantly associated with the occurrence of AF. A LAScd cutoff value of - 11% had a sensitivity of 76% and a specificity of 75% to identify patients with AF. The 30-day cumulative risk of AF was 42 ± 9% with LAScd > - 11% and 8 ± 4% with LAScd ≤ - 11% (log rank test P value < 0.0001).

CONCLUSION

For patients with severe COVID-19 pneumonia, development of AF during ICU stay is common (20%). LAS parameters seem useful in predicting AF within the first 48 h of ICU admission.

TRIAL REGISTRATION

NCT04354558.

Usefulness of Right Ventricular Longitudinal Shortening Fraction to Detect Right Ventricular Dysfunction in Acute Cor Pulmonale Related to COVID-19

OBJECTIVE

To compare two-dimensional-speckle tracking echocardiographic parameters (2D-STE) and classic echocardiographic parameters of right ventricular (RV) systolic function in patients with coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (CARDS) complicated or not by acute cor pulmonale (ACP).

DESIGN

Prospective, between March 1, 2020 and April 15, 2020.

SETTING

Intensive care unit of Amiens University Hospital (France).

PARTICIPANTS

Adult patients with moderate-to-severe CARDS under mechanical ventilation for fewer than 24 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Tricuspid annular displacement (TAD) parameters (TAD-septal, TAD-lateral, and RV longitudinal shortening fraction [RV-LSF]), RV global longitudinal strain (RV-GLS), and RV free wall longitudinal strain (RVFWLS) were measured using transesophageal echocardiography with a dedicated software and compared with classic RV systolic parameters (RV-FAC, S' wave, and tricuspid annular plane systolic excursion [TAPSE]). RV systolic dysfunction was defined as RV-FAC <35%. Twenty-nine consecutive patients with moderate-to-severe CARDS were included. ACP was diagnosed in 12 patients (41%). 2D-STE parameters were markedly altered in the ACP group, and no significant difference was found between patients with and without ACP for classic RV parameters (RV-FAC, S' wave, and TAPSE). In the ACP group, RV-LSF (17% [14%-22%]) had the best correlation with RV-FAC (r = 0.79, p < 0.001 v r = 0.27, p = 0.39 for RVGLS and r = 0.28, p = 0.39 for RVFWLS). A RV-LSF cut-off value of 17% had a sensitivity of 80% and a specificity of 86% to identify RV systolic dysfunction.

CONCLUSIONS

Classic RV function parameters were not altered by ACP in patients with CARDS, contrary to 2D-STE parameters. RV-LSF seems to be a valuable parameter to detect early RV systolic dysfunction in CARDS patients with ACP.

Cardiac ultrasound and abdominal compartment syndrome

This review focuses on the available literature published about the evaluation of haemodynamic consequences of the abdominal compartment syndrome (ACS). Animal and clinical studies described decreased venous return, systemic vasoconstriction, systolic and diastolic dysfunction of left and right ventricles. Doppler echocardiography is a non-invasive bedside procedure which provides a complete haemodynamic evaluation of patients with ACS. Despite numerous evaluations in anesthesia during laparoscopic surgery, the use of echocardiography remains scarce in critically ill patients with ACS.

Antifungal Prevention of Systemic Candidiasis in Immunocompetent ICU Adults: Systematic Review and Meta-Analysis of Clinical Trials

OBJECTIVES

The aim of this study was to identify the impact of antifungal prevention in critically ill immunocompetent adult patients on mortality and subsequent infection.

DATA SOURCES

A systematic review and meta-analysis of randomized controlled trials comparing any antifungal use versus placebo to prevent candidiasis in ICU patients were performed.

STUDY SELECTION

Searches were performed on PubMed, Embase, Scopus, main conference proceedings, and ClinicalTrials.gov, as well as reference lists.

DATA EXTRACTION

The primary outcomes were mortality and invasive candidiasis. The secondary outcome was the rate of Candida albicans and nonalbicans strains after treatment. A random effect model was used, and sensitivity analysis was performed for both outcomes. Results are expressed as risk ratios and their 95% CIs.

DATA SYNTHESIS

Nineteen trials (10 with fluconazole, four with ketoconazole, one with itraconazole, three with micafungin, and one with caspofungin) including 2,792 patients were identified. No individual trial showed a decreased mortality rate. Combined analysis showed that preventive antifungal did not decrease mortality (risk ratio, 0.88; 95% CI, 0.74-1.04; p = 0.14) but significantly decreased secondary fungal infections by 50% (risk ratio, 0.49; 95% CI, 0.35-0.68; p = 0.0001). No shift across nonalbicans strains was observed during treatment (risk ratio, 0.62; 95% CI, 0.19-1.97; p = 0.42). However, publication biases preclude any definite conclusions for prevention of infection.

CONCLUSIONS

Antifungal prevention of systemic candidiasis in immunocompetent critically ill adults did not reduce mortality and may have decreased secondary fungal infection rates. However, significant publication bias was present.

Short- versus Long-Sarafotoxins: Two Structurally Related Snake Toxins with Very Different in vivo Haemodynamic Effects

Sarafotoxin-m (24 amino acids) from the venom of Atractaspis microlepidota microlepidota was the first long-sarafotoxin to be identified, while sarafotoxin-b (21 aa) is a short-sarafotoxin from Atractaspis engaddensis. Despite the presence of three additional C-terminus residues in sarafotoxin-m, these two peptides display a high sequence homology and share similar three-dimensional structures. However, unlike sarafotoxin-b, sarafotoxin-m shows a very low in vitro affinity for endothelin receptors, but still has a very high in vivo toxicity in mammals, similar to that of sarafotoxin-b. We have previously demonstrated, in vitro, the crucial role of the C-terminus extension in terms of pharmacological profiles and receptor affinities of long- versus short-sarafotoxins. One possible hypothesis to explain the high in vivo toxicity of sarafotoxin-m could be that its C-terminus extension is processed in vivo, resulting in short-like sarafotoxin. To address this possibility, we investigated, in the present study, the in vivo cardiovascular effects of sarafotoxin-b, sarafotoxin-m and sarafotoxin-m-Cter (sarafotoxin-m without the C -terminus extension). Male Wistar rats were anaesthetised and mechanically ventilated. Invasive haemodynamic measurements and echocardiographic measurements of left and right ventricular function were performed. The rats were divided into four groups that respectively received intravenous injections of: saline, sarafotoxin-b (one LD50), sarafotoxin-m (one LD50) or sarafotoxin-m-Cter (one LD50). All measurements were performed at baseline, at 1 minute (+1) and at 6 minutes (+6) after injection.

RESULTS

Sarafotoxin-b and sarafotoxin-m-Cter decreased cardiac output and impaired left ventricle systolic and diastolic function, whilst sarafotoxin-m decreased cardiac output, increased airway pressures and led to acute right ventricular dilatation associated with a decreased tricuspid annulus peak systolic velocity. Sarafotoxin-b and sarafotoxin-m-Cter appear to exert toxic effects via impairment of left ventricular function, whilst sarafotoxin-m increases airway pressures and impairs right ventricular function. These results do not support the hypothesis of an in vivo processing of long sarafotoxins.

Burnout syndrome in critical care team members: A monocentric cross sectional survey

INTRODUCTION

There has been a growing interest in evaluating the occurrence of burnout syndrome (BOS) among intensive care units (ICU) team over recent years. The aims of this study were to determine the prevalence of BOS among staff working in the Amiens University Hospital and to assess associated factors.

PATIENTS AND METHODS

Prospective observational study based on self-administered questionnaires filled in by physicians and non-physicians working in 3 ICUs. Demographic data, well-being assessment, work relationships, level of BOS and depressive symptoms were investigated. Logistic regression analysis was performed to identify variables independently associated with BOS.

RESULTS

One hundred and sixty-one questionnaires were analysed. Participation rate was 90%. Thirty-two respondents were physicians and 129 were non-physicians. The prevalence of BOS was 51% and was not significantly different between physicians and non-physicians (56% versus 50%; P=0.501). Respondents who reported BOS less frequently had regular leisure activities (54 [66%] versus 70 [87%], P=0.001). In the BOS group, well-being was significantly lower (4.8±2.5/10 versus 6±2/10, P=0.001), a desire to leave the job was more frequently expressed (50 [61%] versus 32 [40%], P=0.009) and depressive symptoms were significantly more frequent (41 [50%] versus 21 [27%], P=0.002). Factors independently associated with BOS were regular leisure activities (OR 0.24 [0.1-0.59]; P=0.002), the presence of depressive symptoms (OR 2.71 [1.26-5.84]; P=0.011) and a well-being visual analogue scale≥5 (OR 0.40 [0.18-0.89]; P=0.024).

CONCLUSIONS

BOS affects all ICU workers and is determined by multiple factors. Leisure activities and measures designed to improve well-being should be promoted.

Compliance with an empirical antimicrobial protocol improves the outcome of complicated intra-abdominal infections: a prospective observational study

BACKGROUND

Despite improvements in medical and surgical care, mortality attributed to complicated intra-abdominal infections (cIAI) remains high. Appropriate initial antimicrobial therapy (ABT) is key to successful management. The main causes of non-compliance with empirical protocols have not been clearly described.

METHODS

An empirical ABT protocol was designed according to guidelines, validated in the institution and widely disseminated. All patients with cIAI (2009-2011) were then prospectively studied to evaluate compliance with this protocol and its impact on outcome. Patients were classified into two groups according to whether or not they received ABT in compliance with the protocol.

RESULTS

310 patients were included: 223 (71.9%) with community-acquired and 87 (28.1%) with healthcare-associated cIAI [mean age 60(17-97) yr, mean SAPS II score 24(16)]. Empirical ABT complied with the protocol in 52.3% of patients. The appropriateness of empirical ABT to target the bacteria isolated was 80%. Independent factors associated with non-compliance with the protocol were the anaesthetist's age ≥36 yr [OR 2.1; 95%CI (1.3-3.4)] and the presence of risk factors for multidrug-resistant bacteria (MDRB) [OR 5.4; 95%CI (3.0-9.5)]. Non-compliance with the protocol was associated with higher mortality (14.9 vs 5.6%, P=0.011) and morbidity: relaparotomy (P=0.047), haemodynamic failure (P=0.001), postoperative pneumonia (P=0.025), longer duration of mechanical ventilation (P<0.001), longer ICU stay (P<0.001) and longer hospital stay (P=0.002). On multivariate logistic regression analysis, non-compliance with the ABT protocol was independently associated with mortality [OR 2.4; 95% CI (1.1-5.7), P=0.04].

CONCLUSIONS

Non-compliance with empirical ABT guidelines in cIAI is associated with increased morbidity and mortality. Information campaigns should target older anaesthetists and risk factors for MDRB.

Portal Vein Pulsatility as a Dynamic Marker of Venous Congestion Following Cardiac Surgery: An Interventional Study Using Positive End-Expiratory Pressure

We aimed to assess variations in the portal vein pulsatility index (PI) during mechanical ventilation following cardiac surgery.

METHOD

After ethical approval, we conducted a prospective monocentric study at Amiens University Hospital. Patients under mechanical ventilation following cardiac surgery were enrolled. Doppler evaluation of the portal vein (PV) was performed by transthoracic echography. The maximum velocity (VMAX) and minimum velocity (VMIN) of the PV were measured in pulsed Doppler mode. The PI was calculated using the following formula (VMAX - VMIN)/(VMax). A positive end-expiratory pressure (PEEP) incremental trial was performed from 0 to 15 cmH2O, with increments of 5 cmH2O. The PI (%) was assessed at baseline and PEEP 5, 10, and 15 cmH2O. Echocardiographic and hemodynamic parameters were recorded.

RESULTS

In total, 144 patients were screened from February 2018 to March 2019 and 29 were enrolled. Central venous pressure significantly increased for each PEEP increment. Stroke volumes were significantly lower after PEEP incrementation, with 52 mL (50-55) at PEEP 0 cmH2O and 30 mL (25-45) at PEEP 15 cmH2O, (p < 0.0001). The PI significantly increased with PEEP incrementation, from 9% (5-15) at PEEP 0 cmH2O to 15% (5-22) at PEEP 5 cmH2O, 34% (23-44) at PEEP 10 cmH2O, and 45% (25-49) at PEEP 15 cmH2O (p < 0.001).

CONCLUSION

In the present study, PI appears to be a dynamic marker of the interaction between mechanical ventilation and right heart pressure after cardiac surgery. The PI could be a useful noninvasive tool to monitor venous congestion associated with mechanical ventilation.

Microvascular flow alterations in critically ill COVID-19 patients: A prospective study

BACKGROUND

Data on microcirculatory pattern of COVID-19 critically ill patients are scarce. The objective was to compare sublingual microcirculation parameters of critically ill patients according to the severity of the disease.

METHODS

The study is a single-center prospective study with critically ill COVID-19 patients admitted in ICU. Sublingual microcirculation was assessed by IDF microscopy within 48 hours of ICU admission. Microcirculatory flow index (MFI), proportion of perfused vessel (PPV), total vessel density (TVD), De Backer score (DBS), perfused vessel density (PVD) and heterogeneity index (HI) were assessed. Patients were divided in 2 groups (severe and critical) according to the World health organization definition.

FINDINGS

From 19th of March to 7th of April 2020, 43 patients were included. Fourteen patients (33%) were in the severe group and twenty-nine patients (67%) in the critical group. Patients in the critical group were all mechanically ventilated. The critical group had significantly higher values of MFI, DBS and PVD in comparison to severe group (respectively, PaCO2: 49 [44-45] vs 36 [33-37] mmHg; p<0,0001, MFI: 2.8 ± 0.2 vs 2.5 ± 0.3; p = 0.001, DBS: 12.7 ± 2.6 vs 10.8 ± 2.0 vessels mm-2; p = 0.033, PVD: 12.5 ± 3.0 vs 10.1 ± 2.4 mm.mm-2; p = 0.020). PPV, HI and TVD were similar between groups Correlation was found between microcirculatory parameters and PaCO2 levels.

CONCLUSION

Critical COVID-19 patients under mechanical ventilation seem to have higher red blood cell velocity than severe non-ventilated patients.

[French national survey on difficult intubation in intensive care units]

OBJECTIVES

Assessing the theoretical knowledge, practical experience of French intensivists, and their compliance with French Anesthesiology and Critical Care Society's difficult airway algorithms of the expert's SFAR conference of 2006.

STUDY DESIGN

Prospective and descriptive national survey.

MATERIAL AND METHODS

An anonymous questionnaire with 40 questions was emailed to physicians working in intensive care units in France.

RESULTS

Five hundred and eight intensivists answered the survey. Ninety-seven percent of physicians reported having a portable storage unit for difficult intubation. As for practical experience, 421 physicians (83 %) have set up less than 10 laryngeal mask airway, 257 (51 %) have performed less than 10 intubations under fibroscopy and 269 (53 %) have never performed a cricothyroidotomy on mannequin, and 331 (65 %) on a patient. In case of emergency intubation, 29 % of them do not use a rapid sequence induction. Three hundred physicians (59 %) use capnography as monitoring of the endotracheal position. Two hundred and nine (42 %) consider they have not been trained to difficult intubation and 443 (87 %) would like to participate in high fidelity simulations mannequin.

CONCLUSIONS

National airway management algorithm was insufficiently followed. Alternative techniques do not seem to be mastered by all physicians. French intensivists expect more training on difficult intubation, including high fidelity simulation.

Portal Vein Pulsatility Index as a Potential Risk of Venous Congestion Assessed by Magnetic Resonance Imaging: A Prospective Study on Healthy Volunteers

High values of the portal vein pulsatility index (PI) have been associated with adverse outcomes in perioperative or critically ill patients. However, data on dynamic changes of PI related to fluid infusion are scarce. We aimed to determine if dynamic changes in PI are associated with the fluid challenge (FC). To address this challenge, we conducted a prospective single-center study. The population study included healthy subjects. FC consisted in the administration of 500 ml of Ringer lactate infusion over 5 min. The portal blood flow and PI were assessed by magnetic resonance imaging. The responsiveness to FC was defined as an increase in the cardiac stroke volume of at least 10% as assessed by echocardiography. We included 24 healthy volunteers. A total of fourteen (58%) subjects were responders, and 10 (42%) were non-responders. In the responder group, FC induced a significant increase in portal blood flow from 881 (762-1,001) at the baseline to 1,010 (778-1,106) ml min-1 (p = 0.005), whilst PI remained stable (from 31 [25-41] to 35 (25-42) %; p = 0.12). In the non-responder group, portal blood flow remained stable after FC (from 1,042 to 1,034 ml min-1; p = 0.084), whereas PI significantly increased from 32 (22-40) to 48% *(25-85) after FC (p = 0.027). PI was negatively correlated to portal blood flow (Rho coefficient = -0.611; p = 0.002). To conclude, PI might be a sensitive marker of early congestion in healthy subjects that did not respond to FC. This finding requires further validation in clinical settings with a larger sample size.