Acute Respiratory Failure Mortality May Be Linked to Intensity of Mechanical Ventilation

In patients with acute respiratory failure, cumulative exposure to high intensities of mechanical ventilation has been shown to be harmful, even for short periods of time, according to the results of an analysis published in the Lancet Respiratory Medicine.

Investigators conducted a registry-based, prospective cohort study, with data obtained from the Toronto Intensive Care Observational Registry (iCORE) between April 11, 2014, and June 5, 2019, to evaluate the association between exposure to different intensities of mechanical ventilation over time and intensive care unit (ICU) mortality in patients with acute respiratory failure.

The Toronto iCORE included all adult patients aged ≥18 years who were received invasive mechanical ventilation for ≥4 hours in 9 ICUs affiliated with the University of Toronto, located in Toronto, Ontario, Canada. The primary study outcome was ICU mortality.

Data from 13,939 patients were recorded in the registry. Individuals who were on extracorporeal life support were excluded (n=531), for a total of 13,408 patients thus included in the descriptive analysis. The mean patient age was 62 years (range, 50-73 years); 38.3% of the patients were women. Most of the patients required mechanical ventilation because of the development of an acute neurologic condition (33.3%) or the presence of acute respiratory failure (70.7%) for a variety of underlying conditions. Some patients had multiple reasons for the use of mechanical ventilation.

Overall, 18.0% (2409 of 13,408) of the patients died in the ICU. Following adjustment for baseline characteristics such as age and severity of illness, a significant increase in the hazard of death was shown to be associated with each daily increment in driving pressure (hazard ratio [HR], 1.064; 95% credible interval [CrI], 1.057-1.071) or in mechanical power (HR, 1.060; 95% CrI, 1.053-1.066). In fact, these associations persisted during the entire duration of mechanical ventilation.

The investigators concluded that the exposure to higher intensities of mechanical ventilation, even for a short duration, was linked to higher rates of mortality at any time during the course of mechanical ventilation. In patients with acute respiratory failure, the use of early, sustained interventions to limit exposure to higher driving pressure and mechanical power during the use of mechanical ventilation might be an important strategy to further decrease mortality in these individuals.

Reference

Urner M, Jüni P, Hansen B, Wettstein MS, Ferguson ND, Fan E. Time-varying intensity of mechanical ventilation and mortality in patients with acute respiratory failure: a registry-based, prospective cohort study. Lancet Respir Med. Published online July 28, 2020. doi:10.1016/S2213-2600(20)30325-8