Outcomes of low tidal volume ventilation in COVID-19 intubated patients

ABSTRACT

INTRODUCTION: Low tidal volume ventilation (LTVV), defined as 6 to 8cc of tidal volume per kilogram of ideal body weight (IBW), has been shown to reduce mortality and days requiring invasive ventilation when utilized in the acute respiratory distress syndrome (ARDS). The degree of hypoxemia in respiratory failure experienced in the SARSCOV2 infection (COVID-19) is similar to ARDS from other respiratory pathologies;however, there appears to be notable heterogeneity in lung compliance of COVID-19 patients as well as higher rate of mortality for ARDS supported with invasive mechanical ventilation in COVID-19. It remains unknown if lung protective tidal volume strategies confer a significant benefit for COVID-19 ARDS as they do for ARDS due to other etiologies. We aim to determine if LTVV was associated with decreased mortality, ventilator days, ICU length of stay, or decreased length of hospital stay. METHODS: A prospective observational study was performed with inclusion criteria of a positive COVID-19 test and intubation for non-operative indications. Ideal body weight was calculated to determine whether or not each patient ever exceeded or achieved LTVV, here defined as less than 6cc/kg of ideal body weight. The primary outcome was mortality. The secondary outcomes were length of stay in the hospital, ICU days, and ventilator days. RESULTS: A total of 75 COVID positive patients were intubated at our facility. 60 (80%) of these patients died. Exceeding 6cc/kg IBW LTVV trended towards more days in the ICU (p=.089) and number of days intubated (p=.148), but only increased hospital length of stay was statistically significant (p=.025). Patients who did maintain LTVV at least one day did have decreased crude odds of mortality at 0.281 (95% CI .0482-1.6395). LTVV was not correlated with fewer ICU days (p=.846), number of days intubated (p=.709), or length of hospital stay (p=.699). CONCLUSIONS: Failure to maintain LTVV was associated with increased mortality and hospital LOS. It also trended toward an increase in ICU days days of mechanical ventilation. Further prospective studies are required.