The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Abstract

Background Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0–171.2] to 180.0 [135.4–227.9] mmHg and the ventilatory ratio from 1.73 [1.33–2.25] to 1.96 [1.61–2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01–1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01–1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93–1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation.

Methodology of a Large Multicenter Observational Study of Patients with COVID-19 in Spanish Intensive Care Units

“…The automation of analysis allowed us to perform many sub-studies concurrently during the project. Nine of those were conducted through the automated analysis methodology, of which two have already been published 17 , 24 and another two are under review with a journal. The remaining five are currently being drafted.…”

“…These issues meant that we did not publish our first manuscript until October 2021, 24 contrasting with other European countries. 1 , 2 However, we spent time and effort to maximize the amount of data with strict quality control, something that the first rapid publications could not achieve.…”

“…Age and increases in the ventilatory ratio and creatinine from day 1 to day 3 independently and significantly predicted in-hospital mortality. 24 The ventilatory ratio, an easily calculated bedside parameter that uses PaCO 2 and minute ventilation, is a surrogate for measuring lung dead space. 5 Studies are ongoing into the impact of delayed intubation, non-invasive ventilatory support, driving pressure, COPD, a very elderly population, and the effectivity of corticosteroids and remdesivir.…”

Anticoagulant Treatment in Severe ARDS COVID-19 Patients

“…Lower platelet count was associated with more severe disease, and thrombocytopenia was associated with higher risk of death [ 25 , 26 ], also lower increase in the number of platelets from day 1 to day 3 was independently associated with death in a multicenter Spanish study [ 27 ].…”

Correction to: The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

“…Following publication of the original article [ 1 ], the authors identified an error in the Funding section.…”