An increase in dynamic compliance (Cdyn) was associated with lower odds of mortality among patients with COVID-19 requiring mechanical ventilation (MV), according to study findings reported in Respiratory Care.
The researchers conducted a retrospective analysis to determine the association between all-cause mortality in patients with COVID-19 receiving mechanical ventilation and respiratory mechanics, oxygenation impairment, social demographics, and comorbid conditions.
The researchers analyzed electronic medical records data from a tertiary correctional care facility of adult patients with a positive COVID-19 diagnosis who underwent invasive mechanical ventilation for at least 5 consecutive days from March 1, 2020, to December 31, 2021. Mortality was the primary outcome and was defined as death before hospital discharge. The study included 415 participants, with a mean [SD] age of 59 [14] years, 60% were male, and 42% were Hispanic/Latino.
Cdyn (calculated as tidal volume/[peak inspiratory pressure – positive end-expiratory pressure]) was significantly higher in surviving patients on day 5 of mechanical ventilation (P =.01). During day 1 of mechanical ventilation, Cdyn, respiratory system compliance (CRS), and airway resistance were not significantly different between the mortality and no-mortality groups.
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Future research is needed to determine if mechanical ventilation protocols aimed at improving compliance in the first 5 days might decrease mortality rates in those infected with COVID-19.
For each 1-mL/cm H2O increase in Cdyn, the odds of mortality were reduced by 3% after controlling for age, sex, race/ethnicity, multimorbidity, oxygenation impairment, airway resistance, and CRS. Greater odds of mortality were found in patients who had oxygenation impairment that was mild (odds ratio [OR] 2.80; 95% CI, 1.30-2.46), moderate (OR 3.74; 95% CI, 1.69-8.3), or severe (OR 10.3; 95% CI, 4.65-23) vs participants who had no oxygenation impairment, after controlling for all study variables.
The odds of mortality increased by 1.05 for each 1-year increase in age, after controlling for all study variables. Hispanic/Latino patients had 1.8 times greater odds of mortality, and non-Hispanic Black patients had 0.53 reduced odds of mortality vs non-Hispanic White patients, after controlling for all study variables. Male participants had 1.5 times increased odds of mortality vs female patients, after controlling for all study variables. Patients with multimorbidity had 0.68 lower mortality odds compared with those without multimorbidity.
Study limitations include the study’s single-center design; possible selection bias; and the continuing changes in clinical practice that occurred throughout the COVID-19 pandemic, which may limit the predictive value of this study.
“It is crucial to evaluate respiratory mechanics and their association with mortality in mechanically ventilated subjects with COVID-19,” noted the investigators. “Age, sex, oxygenation impairment, and Cdyn can be considered in managing mechanically ventilated subjects with COVID-19. Future research is needed to determine if mechanical ventilation protocols aimed at improving compliance in the first 5 days might decrease mortality rates in those infected with COVID-19.”
