Long-term survival comparison between the first and second waves among 265 critical COVID-19 patients admitted to the ICU: A retrospective cohort study.

BACKGROUD: Management of severe COVID-19 patients admitted to ICU considerably evolved during the first months of the pandemic. It is unclear, however, whether these changes improved long-term survival of these critically ill patients. METHODS: We conducted a retrospective cohort study in adults with COVID-19 pneumonia admitted to a French ICU between February 2020 and January 2021, a timeframe that covered the first two waves of the pandemic. Primary outcome was to compare long-term survival between the first and second waves. Survival predictor were identified using a Cox proportional-hazards model. RESULTS: We included 265 patients in the cohort: 140 (52.8 %) and 125 (47.2 %) belonging to the first and second waves, respectively. Baseline characteristics of the patients were similar between the two waves. During W2, use of early corticotherapy increased (86.4% vs. 17.8 %; p <0.001), as well as high-flow oxygen therapy use (68.5% vs. 37.4 %; p<0.001). Need for invasive mechanical ventilation decreased (49.6% vs. 72.9 %; p <0.001) and ICU length of stay was shorter (11 [6-22] vs 19 [8-32]days; p = 0.008). ICU mortality was 32.8 % without significant difference between waves. Survival analysis revealed that 3 variables were independently associated with a worse long-term prognosis: a higher SAPS II score (1.05 [1.04-1.06]; p<0.001), a higher age (1.05 [1.01-1.08]; p = 0.005) and admission during W2 (2.22 [1.15-4.28]; p = 0.017). DISCUSSION: Despite substantial changes on management of severe COVID-19 patients, we observed a decreased long-term survival among patients admitted during the second wave. We also noted a shorter ICU length of stay.

Assist-control ventilation vs. low levels of pressure support ventilation on sleep quality in intubated ICU patients.

OBJECTIVE: To compare the impact of assist-control ventilation (ACV) and pressure support ventilation with 6 cmH2O inspiratory pressure (low PSV) on sleep quality. DESIGN: Prospective randomized cross-over study. PATIENTS: Twenty intubated and mechanically ventilated patients for acute on chronic respiratory failure. MEASUREMENTS: Patients were monitored by standard polysomnography at the end of their weaning period. Patients were assigned to receive either ACV from 10 p.m. to 2 a.m. and low PSV from 2 a.m. to 6 a.m. (ACV/low PSV group) or low PSV from 10 p.m. to 2 a.m. and ACV from 2 a.m. to 6 a.m. (low PSV/ACV group). RESULTS: There were significant increases in stages 1 and 2 non-rapid eye movement (NREM) sleep and reduction in wakefulness during the first part of the night and significant increases in stages 3 and 4 NREM sleep during the second part of the night were observed with ACV compared to low PSV. A significant negative correlation was observed between the perceived sleep quality and the amount of wakefulness while the amount of stage 2 NREM sleep was positively correlated with perceived sleep quality. CONCLUSIONS: ACV was significantly associated with a better sleep quality than those recorded during pressure support. The perception of sleep quality appeared to be better with ACV than with low PSV. On the basis of these results we recommend that intubated and mechanically ventilated patients for acute on chronic respiratory failure should be reventilated at night during their weaning period.

Does using pressure-controlled ventilation to rest respiratory muscles improve sleep in ICU patients?

PURPOSE: Sleep is commonly altered in critically ill patients. Ventilatory mode may impact on quality of sleep. The aim of our study was to evaluate the effect on sleep of pressure-controlled ventilation (PCV) to spontaneous ventilation with 6 cm H2O inspiratory pressure (low-PSV). METHODS: Thirty-five patients intubated and mechanically ventilated for acute-on-chronic respiratory failure were included in this prospective randomized cross-over study. Nine were discarded, 13 received PCV first (10 p.m.-2 a.m.) and then low-PSV (2-6 a.m.) and 13 patients received low-PSV first and then PCV. RESULTS: Sleep architecture was altered (50.4% of the night was spent in wakefulness). PCV was associated with significantly improved sleep quality and quantity compared to low-PSV: sleep efficiency (total sleep time/total recording time) was 63% (range: 9-100) vs. 37% (0-96; p = 0.0002), stage 2 NREM sleep was 33% vs. 13% (p = 0.0005), stages 3 and 4 NREM sleep were 9% vs. 3.5% (p = 0.003) and REM sleep was 6.5% vs. 0% (p = 0.003). CONCLUSIONS: Sleep quantity and quality were significantly improved with PCV compared to low-PSV. Nocturnal respiratory muscles rest through PCV is recommended to improve sleep in ICU patients with acute-on-chronic respiratory failure.