An Initial Investigation of Diaphragm Neurostimulation in Patients with Acute Respiratory Distress Syndrome.

BACKGROUND: Lung protective ventilation aims at limiting lung stress and strain. By reducing the amount of pressure transmitted by the ventilator into the lungs, diaphragm neurostimulation offers a promising approach to minimize ventilator-induced lung injury. This study investigates the physiologic effects of diaphragm neurostimulation in acute respiratory distress syndrome (ARDS) patients. The hypothesis was that diaphragm neurostimulation would improve oxygenation, would limit the distending pressures of the lungs, and would improve cardiac output. METHODS: Patients with moderate ARDS were included after 48 h of invasive mechanical ventilation and had a left subclavian catheter placed to deliver bilateral transvenous phrenic nerve stimulation. Two 60-min volume-controlled mechanical ventilation (control) sessions were interspersed by two 60-min diaphragm neurostimulation sessions delivered continually, in synchrony with the ventilator. Gas exchange, lung mechanics, chest electrical impedance tomography, and cardiac index were continuously monitored and compared across four sessions. The primary endpoint was the Pao2/fraction of inspired oxygen (Fio2) ratio at the end of each session, and the secondary endpoints were lung mechanics and hemodynamics. RESULTS: Thirteen patients were enrolled but the catheter could not be inserted in one, leaving 12 patients for analysis. All sessions were conducted without interruption and well tolerated. The Pao2/Fio2 ratio did not change during the four sessions. Median (interquartile range) plateau pressure was 23 (20 to 31) cm H2O and 21 (17 to 25) cm H2O, driving pressure was 14 (12 to 18) cm H2O and 11 (10 to 13) cm H2O, and end-inspiratory transpulmonary pressure was 9 (5 to 11) cm H2O and 7 (4 to 11) cm H2O during mechanical ventilation alone and during mechanical ventilation + neurostimulation session, respectively. The dorsal/ventral ventilation surface ratio was 0.70 (0.54 to 0.91) when on mechanical ventilation and 1.20 (0.76 to 1.33) during the mechanical ventilation + neurostimulation session. The cardiac index was 2.7 (2.3 to 3.5) l · min-1 · m-2 on mechanical ventilation and 3.0 (2.4 to 3.9) l · min-1 · m-2 on mechanical ventilation + neurostimulation. CONCLUSIONS: This proof-of-concept study showed the feasibility of short-term diaphragm neurostimulation in conjunction with mechanical ventilation in ARDS patients. Diaphragm neurostimulation was associated with positive effects on lung mechanics and on hemodynamics.

Association between selective digestive decontamination and decreased rate of acquired candidemia in mechanically ventilated ICU patients: a multicenter nationwide study.

BACKGROUND: Candidemia is a high-risk complication among intensive care unit (ICU) patients. While selective digestive decontamination (SDD) has been shown to be effective in preventing ICU-acquired bacterial secondary infection, its effects on ICU-acquired candidemia (ICAC) remain poorly explored. Therefore, we sought to assess the effects of SDD on ICAC. METHOD: Using the REA-REZO network, we included adult patients receiving mechanical ventilation for at least 48 h from January 2017 to January 2023. Non-parsimonious propensity score matching with a 1:1 ratio was performed to investigate the association between SDD and the rate of ICAC. RESULTS: A total of 94 437 patients receiving at least 48 h of mechanical ventilation were included throughout the study period. Of those, 3 001 were treated with SDD and 651 patients developed ICAC. The propensity score matching included 2 931 patients in the SDD group and in the standard care group. In the matched cohort analysis as well as in the overall population, the rate of ICAC was lower in patients receiving SDD (0.8% versus 0.3%; p = 0.012 and 0.7% versus 0.3%; p = 0.006, respectively). Patients with ICAC had higher mortality rate (48.4% versus 29.8%; p < 0.001). Finally, mortality rates as well as ICU length of stay in the matched populations did not differ according to SDD (31.0% versus 31.1%; p = 0.910 and 9 days [5-18] versus 9 days [5-17]; p = 0.513, respectively). CONCLUSION: In this study with a low prevalence of ICAC, SDD was associated with a lower rate of ICAC that did not translate to higher survival.

Fatal Clostridium septicum gas gangrene complicating ECMO: case report and review of literature.

Clostridium septicum gas gangrene is a severe and deadly infection caused by an anaerobic, spore-forming, Gram-positive bacillus. As previously described, two entities are observed: traumatic and spontaneous (or non-traumatic) forms. In this report, we aim to describe the case of a fulminant and ultimately fatal C. septicum myonecrosis occurring in a patient who was first admitted for refractory cardiac arrest and placed on veino-arterial extracorporeal membrane oxygenation (ECMO). Building upon prior studies that have documented cases of spontaneous gas gangrene caused by C. septicum, we provide an updated compilation, focusing on microbiological characteristics of C. septicum, along with the diagnostic and therapeutic challenges associated with spontaneous gas gangrene. Additionally, the specific clinical situation of our case illustrates the seriousness of this infectious complication that combined both spontaneous and traumatic gas gangrene risk factors. We thus, discuss the antibiotic coverage prior to the initiation of ECMO procedure.

Admission chest CT scan of intensive care patients with interstitial lung disease: Unveiling its limited predictive value through visual and automated analyses in a retrospective study (ILDICTO).

BACKGROUND: Clinical course prediction of patients with interstitial lung disease (ILD) admitted to the intensive care unit (ICU) for acute respiratory failure (ARF) can be challenging. This study aimed to characterize the prognostic value of admission chest CT-scan in this situation. METHODS: We retrospectively included ILD patients admitted to a French ICU for acute respiratory failure requiring oxygen. Patients with lymphangitis carcinomatosis and ANCA vasculitis were excluded. We analyzed every admission chest CT-scan using two different approaches: a visual analysis (grading the extent of traction bronchiectasis, ground glass and honeycomb) and an automated analysis (grading the extent of ground glass and consolidation with a dedicated software). The primary outcome was ICU mortality. RESULTS: Between January 2014 and October 2020, 81 patients presented an acute respiratory failure with ILD on the admission chest CT-scan. In univariate analysis, only the main pulmonary artery diameter differed between patients who survived and those who died in ICU (30 vs 32 mm, p = 0.021). In multivariate analysis, none of the radiological funding was associated with ICU mortality. Visual and automated analyses did not yield different results, with a strong correlation between the two methods. However, the identification of an UIP pattern (and the presence of honeycomb) was associated with a poorer response to corticosteroid therapy. CONCLUSION: Our study showed that the extent of radiological findings and the severity of fibrosis indices on admission chest CT scans of ILD patients admitted to the ICU for ARF were not associated with subsequent deterioration.

Impact of intensive prone position therapy on outcomes in intubated patients with ARDS related to COVID-19.

BACKGROUND: Previous retrospective research has shown that maintaining prone positioning (PP) for an average of 40 h is associated with an increase of survival rates in intubated patients with COVID-19-related acute respiratory distress syndrome (ARDS). This study aims to determine whether a cumulative PP duration of more than 32 h during the first 2 days of intensive care unit (ICU) admission is associated with increased survival compared to a cumulative PP duration of 32 h or less. METHODS: This study is an ancillary analysis from a previous large international observational study involving intubated patients placed in PP in the first 48 h of ICU admission in 149 ICUs across France, Belgium and Switzerland. Given that PP is recommended for a 16-h daily duration, intensive PP was defined as a cumulated duration of more than 32 h during the first 48 h, whereas standard PP was defined as a duration equal to or less than 32 h. Patients were followed-up for 90 days. The primary outcome was mortality at day 60. An Inverse Probability Censoring Weighting (IPCW) Cox model including a target emulation trial method was used to analyze the data. RESULTS: Out of 2137 intubated patients, 753 were placed in PP during the first 48 h of ICU admission. The intensive PP group (n = 79) had a median PP duration of 36 h, while standard PP group (n = 674) had a median of 16 h during the first 48 h. Sixty-day mortality rate in the intensive PP group was 39.2% compared to 38.7% in the standard PP group (p = 0.93). Twenty-eight-day and 90-day mortality as well as the ventilator-free days until day 28 were similar in both groups. After IPCW, there was no significant difference in mortality at day 60 between the two-study groups (HR 0.95 [0.52-1.74], p = 0.87 and HR 1.1 [0.77-1.57], p = 0.61 in complete case analysis or in multiple imputation analysis, respectively). CONCLUSIONS: This secondary analysis of a large multicenter European cohort of intubated patients with ARDS due to COVID-19 found that intensive PP during the first 48 h did not provide a survival benefit compared to standard PP.

Diaphragm function in patients with Covid-19-related acute respiratory distress syndrome on venovenous extracorporeal membrane oxygenation.

BACKGROUND: Venovenous extracorporeal membrane oxygenation (VV ECMO) is frequently associated with deep sedation and neuromuscular blockades, that may lead to diaphragm dysfunction. However, the prevalence, risk factors, and evolution of diaphragm dysfunction in patients with VV ECMO are unknown. We hypothesized that the prevalence of diaphragm dysfunction is high and that diaphragm activity influences diaphragm function changes. METHODS: Patients with acute respiratory distress syndrome (ARDS) requiring VV ECMO were included in two centers. Diaphragm function was serially assessed by measuring the tracheal pressure in response to phrenic nerve stimulation (Ptr,stim) from ECMO initiation (Day 1) until ECMO weaning. Diaphragm activity was estimated from the percentage of spontaneous breathing ventilation and by measuring the diaphragm thickening fraction (TFdi) with ultrasound. RESULTS: Sixty-three patients were included after a median of 4 days (3-6) of invasive mechanical ventilation. Diaphragm dysfunction, defined by Ptr, stim ≤ 11 cmH2O, was present in 39 patients (62%) on Day 1 of ECMO. Diaphragm function did not change over the study period and was not influenced by the percentage of spontaneous breathing ventilation or the TFdi during the 1 week. Among the 63 patients enrolled in the study, 24 (38%) were still alive at the end of the study period (60 days). CONCLUSIONS: Sixty-two percent of patients undergoing ECMO for ARDS related to SARS CoV-2 infection had a diaphragm dysfunction on Day 1 of ECMO initiation. Diaphragm function remains stable over time and was not associated with the percentage of time with spontaneous breathing. CLINICALTRIALS: gov Identifier NCT04613752 (date of registration February 15, 2021).

Lung aeration estimated by chest electrical impedance tomography and lung ultrasound during extubation.

BACKGROUND: This study hypothesized that patients with extubation failure exhibit a loss of lung aeration and heterogeneity in air distribution, which could be monitored by chest EIT and lung ultrasound. Patients at risk of extubation failure were included after a successful spontaneous breathing trial. Lung ultrasound [with calculation of lung ultrasound score (LUS)] and chest EIT [with calculation of the global inhomogeneity index, frontback center of ventilation (CoV), regional ventilation delay (RVD) and surface available for ventilation] were performed before extubation during pressure support ventilation (H0) and two hours after extubation during spontaneous breathing (H2). EIT was then repeated 6 h (H6) after extubation. EIT derived indices and LUS were compared between patients successfully extubated and patients with extubation failure. RESULTS: 40 patients were included, of whom 12 (30%) failed extubation. Before extubation, when compared with patients with successful extubation, patients who failed extubation had a higher LUS (19 vs 10, p = 0.003) and a smaller surface available for ventilation (352 vs 406 pixels, p = 0.042). After extubation, GI index and LUS were higher in the extubation failure group, whereas the surface available for ventilation was lower. The RVD and the CoV were not different between groups. CONCLUSION: Before extubation, a loss of lung aeration was observed in patients who developed extubation failure afterwards. After extubation, this loss of lung aeration persisted and was associated with regional lung ventilation heterogeneity. Trial registration Clinical trials, NCT04180410, Registered 27 November 2019-prospectively registered, https://clinicaltrials.gov/ct2/show/NCT04180410 .

Moderate-to-severe ARDS: COVID-19 patients compared to influenza patients for ventilator parameters and mortality.

Background: This study aimed to compare ventilatory parameters recorded in the first days of acute respiratory distress syndrome (ARDS) and mortality at day 60 between coronavirus disease 2019 (COVID-19) and influenza ARDS patients with arterial oxygen tension (P aO2 )/inspiratory oxygen fraction (F IO2 ) ≤150 mmHg. Methods: We compared 244 COVID-19 ARDS patients with 106 influenza ARDS patients. Driving pressure, respiratory system compliance (C rs), ventilator ratio, corrected minute ventilation (V'Ecorr) and surrogate of mechanical power (index=(4×driving pressure)+respiratory rate) were calculated from day 1 to day 5 of ARDS. A propensity score analysis and a principal component analysis (PCA) were performed. Results: On day 1 of ARDS, COVID-19 patients had significantly higher P aO2 /F IO2 (median (interquartile range) 97 (79-129.2) versus 83 (62.2-114) mmHg; p=0.001), and lower driving pressure (13.0 (11.0-16.0) versus 14.0 (12.0-16.7) cmH2O; p=0.01), ventilatory ratio (2.08 (1.73-2.49 versus 2.52 (1.97-3.03); p<0.001), V'Ecorr (12.7 (10.2-14.9) versus 14.9 (11.6-18.6) L·min-1; p<0.001) and index (80 (70-89) versus 84 (75-94); p=0.004). PCA demonstrated an important overlap of ventilatory parameters recorded on day 1 between the two groups. From day 1 to day 5, repeated values of P aO2 /F IO2 , arterial carbon dioxide tension, ventilatory ratio and V'Ecorr differed significantly between influenza and COVID-19 patients in the unmatched and matched populations. Mortality at day 60 did not differ significantly after matching (29% versus 21.7%; p=0.43). Conclusions: Ventilation was more impaired in influenza than in COVID-19 ARDS patients on the first day of ARDS with an important overlap of values. However, mortality at day 60 did not differ significantly in the matched population.

Impact on ICU mortality of moderate alcohol consumption in patients admitted with infection.

PURPOSE: Alcohol dependence is associated with poor prognosis in the intensive care unit (ICU), but it remains uncertain whether moderate alcohol consumption negatively affects the prognosis of critically ill patients admitted with infection. MATERIALS AND METHODS: In a prospective observational cohort study performed in 478 patients admitted with documented infection, mortality at day 28 in the group of abstainers and nontrauma patients with estimated alcohol consumption lower than 100 g/week was compared with that in non-alcohol-dependent patients with estimated alcohol consumption between 100 and 350 g/week. RESULTS: In 97 patients (20%), alcohol consumption was estimated to be over 100 g/week, and in 391 patients (80%), alcohol consumption was estimated to be 100 g/week or less. The pathogens identified did not significantly differ between the two groups of patients. After adjusted analysis, alcohol consumption between 100 and 350 g/week remained significantly associated with mortality at day 28 (hazard ratio (HR): 1.67; 95% confidence interval (CI): 1.01-2.77; p = .04). CONCLUSION: Alcohol consumption between 100 and 350 g/week was independently associated with mortality at day 28. Our results suggest that in critically ill patients admitted with infection, moderate alcohol consumption is associated with a poorer prognosis.