Association of ventilator type with hospital mortality in critically ill patients with SARS-CoV2 infection: a prospective study

Should Transport Ventilators Be Used in Times of Crisis? The Use of Emergency Authorized Nonconventional Ventilators Is Associated With Mortality Among Patients With COVID-19 Acute Respiratory Distress Syndrome

OBJECTIVES

Nonconventional ventilators (NCVs), defined here as transport ventilators and certain noninvasive positive pressure devices, were used extensively as crisis-time ventilators for intubated patients with COVID-19. We assessed whether there was an association between the use of NCV and higher mortality, independent of other factors.

DESIGN

This is a multicenter retrospective observational study.

SETTING

The sample was recruited from a single healthcare system in New York. The recruitment period spanned from March 1, 2020, to April 30, 2020.

PATIENTS

The sample includes patients who were intubated for COVID-19 acute respiratory distress syndrome (ARDS).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was 28-day in-hospital mortality. Multivariable logistic regression was used to derive the odds of mortality among patients managed exclusively with NCV throughout their ventilation period compared with the remainder of the sample while adjusting for other factors. A secondary analysis was also done, in which the mortality of a subset of the sample exclusively ventilated with NCV was compared with that of a propensity score-matched subset of the control group. Exclusive use of NCV was associated with a higher 28-day in-hospital mortality while adjusting for confounders in the regression analysis (odds ratio, 1.41; 95% CI [1.07-1.86]). In the propensity score matching analysis, the mortality of patients exclusively ventilated with NCV was 68.9%, and that of the control was 60.7% ( p = 0.02).

CONCLUSIONS

Use of NCV was associated with increased mortality among patients with COVID-19 ARDS. More lives may be saved during future ventilator shortages if more full-feature ICU ventilators, rather than NCVs, are reserved in national and local stockpiles.

1-year survival rate of SARS-CoV-2 infected patients with acute respiratory distress syndrome based on ventilator types: a multi-center study

The aim of this study was to evaluate the association between types of ventilator and the one-year survival rate of patients with acute respiratory distress syndrome (ARDS) due to SARS‑CoV-2 infection. This multi-center, retrospective observational study was conducted on 1078 adult patients admitted to five university-affiliated hospitals in Iran who underwent mechanical ventilator (MV) due to ARDS. Of the 1078 patients, 781 (72.4%) were managed with ICU ventilators and 297 (27.6%) with transport ventilators. Overall mortality was significantly higher in patients supported with transport ventilator compared to patients supported with ICU ventilator (16.5% vs. 9.3% P = 0.001). Regression analysis revealed that the expected hazard overall increased with age (HR: 1.525, 95% CI 1.112-1.938, P = 0.001), opacity score (HR: 1.448, 95% CI 1.122-2.074, P = 0.001) and transport ventilator versus ICU ventilator (HR: 1.511, 95% CI 1.143-2.187, P = 0.029). The Kaplan-Meier curves of survival analysis showed that patients supported with ICU ventilator had a significantly higher 1-year survival rate (P = 0.001). In MV patients with ARDS due to COVID-19, management with non-ICU sophisticated ventilators was associated with a higher mortality rate compared to standard ICU ventilators. However, more studies are needed to determine the exact effect of ventilator types on the outcome of critically ill patients.

Mechanical Ventilation in ARDS With an Automatic Resuscitator

BACKGROUND

The Oxylator is an automatic resuscitator, powered only by an oxygen cylinder with no electricity required, that could be used in acute respiratory failure in situations in which standard mechanical ventilation is not available or feasible. We aimed to assess the feasibility and safety of mechanical ventilation by using this automatic resuscitator in an animal model of ARDS.

METHODS

A randomized experimental study in a porcine ARDS model with 12 pigs randomized to the Oxylator group or the control group (6 per group) and ventilated for 4 h. In the Oxylator group, peak pressure was set at 20 cm H2O and PEEP was set at the lowest observed breathing frequency during a decremental PEEP titration. The control pigs were ventilated with a conventional ventilator by using protective settings and PEEP at the crossing point of collapse and overdistention, as indicated by electrical impedance tomography. Our end points were feasibility and safety as well as respiratory mechanics, gas exchange, and hemodynamics.

RESULTS

After lung injury, the mean ± SD respiratory system compliance and PaO2 /FIO2 were 13 ± 2 mL/cm H2O and 61 ± 17 mm Hg, respectively. The mean ± SD total PEEP was 10 ± 2 cm H2O and 13 ± 2 cm H2O in the control and Oxylator groups, respectively (P = .046). The mean plateau pressure was kept to < 30 cm H2O in both groups. In the Oxylator group, the tidal volume was transiently > 8 mL/kg but was 6 ± 0.4 mL/kg at 4 h, whereas the breathing frequency increased from 38 ± 4 to 48 ± 3 breaths/min (P < .001). There was no difference in driving pressure, compliance, PaO2 /FIO2 , and pulmonary shunt between the groups. The mean ± SD PaCO2 was higher in the Oxylator group after 4 h, 74 ± 9 mm Hg versus 58 ± 6 mm Hg (P < .001). There were no differences in hemodynamics between the groups, including blood pressure and cardiac output.

CONCLUSIONS

Short-term mechanical ventilation by using an automatic resuscitator and a fixed pressure setting in an ARDS animal model was feasible and safe.

Temporary ICUs during the COVID-19 pandemic first wave: description of the cohort at a French centre

Background

During the COVID-19 first wave in France, the capacity of intensive care unit (ICU) beds almost doubled, mainly because of the opening of temporary ICUs with staff and equipment from anaesthesia.

Objectives

We aim to investigate if the initial management in temporary ICU is associated with a change in ICU mortality and short-term prognosis.

Design

Retrospective single-centre cohort study.

Setting

Surgical ICU of the Bichat Claude Bernard University Hospital during the COVID-19 “first wave” (from 18 March to 10 April 2020).

Patients

All consecutive patients older than 18 years of age with laboratory-confirmed SARS-CoV-2 infection and/or typical radiological patterns were included during their first stay in the ICU for COVID-19.

Intervention

Patients were admitted to a temporary ICU if no room was available in the classical ICU and if they needed invasive mechanical ventilation but no renal replacement therapy or Extracorporeal Membrane Oxygenation (ECMO) in the short term. The temporary ICUs were managed by mixed teams (from the ICU and anaesthesiology departments) following a common protocol and staff meetings.

Main outcome measure

ICU mortality

Results

Among the 59 patients admitted, 37 (62.7%) patients had initial management in the temporary ICU. They had the same characteristics on admission and the same medical management as patients admitted to the classical ICU. ICU mortality was similar in the 2 groups (32.4% in temporary ICUs versus 40.9% in classical ICUs; p=0.58). SAPS-II and ECMO use were associated with mortality in multivariate analysis but not admission to the temporary ICU.

Conclusion

In an overload context of the ICU of a geographical area, our temporary ICU model allowed access to intensive care for all patients requiring it without endangering them.