Hourly Analysis of Mechanical Ventilation Parameters in Critically Ill Adult Covid-19 Patients: Association with Mortality.

Objective: There exists controversy about the pathophysiology and lung mechanics of COVID-19 associated acute respiratory distress syndrome (ARDS), because some report severe hypoxemia with preserved respiratory system mechanics, contrasting with "classic" ARDS. We performed a detailed hourly analysis of the characteristics and time course of lung mechanics and biochemical analysis of patients requiring invasive mechanical ventilation (IMV) for COVID-19-associated ARDS, comparing survivors and non-survivors. Methods: Retrospective analysis of the data stored in the ICU information system of patients admitted in our hospital ICU that required IMV due to confirmed SARS-CoV-2 pneumonia between March 5th and April 30th, 2020. We compare respiratory system mechanics and gas exchange during the first ten days of IMV, discriminating volume and pressure controlled modes, between ICU survivors and non-survivors. Results: 140 patients were included, analyzing 11 138 respiratory mechanics recordings. Global mortality was 38.6%. Multivariate analysis showed that age (OR 1.092, 95% (CI 1.014-1.176)) and need of renal replacement therapies (OR 10.15, (95% CI 1.58-65.11)) were associated with higher mortality. Previous use of Angiotensin Converting Enzyme inhibitor (ACEI)/angiotensin-receptor blockers (ARBs) also seemed to show an increased mortality (OR 4.612, (95% CI 1.19-17.84)) although this significance was lost when stratifying by age. Respiratory variables start to diverge significantly between survivors and non-survivors after the 96 to 120 hours (hs) from mechanical ventilation initiation, particularly respiratory system compliance. In non survivors, mechanical power at 24 and 96 hs was higher regardless ventilatory mode. Conclusions: In patients admitted for SARS-CoV-2 pneumonia and requiring mechanical ventilation, non survivors have different respiratory system mechanics than survivors in the first 10 days of ICU admission. We propose a checkpoint at 96-120 hs to assess patients improvement or worsening in order to consider escalating to extracorporeal therapies.

Predictors of mechanical ventilation and mortality in critically ill patients with COVID-19 pneumonia / Predictores de ventilación mecánica y mortalidad en pacientes críticos con neumonía por COVID-19

Objective To determine if potential predictors for invasive mechanical ventilation (IMV) are also determinants for mortality in COVID-19-associated acute respiratory distress syndrome (C-ARDS). Design Single center highly detailed longitudinal observational study. Setting Tertiary hospital ICU: two first COVID-19 pandemic waves, Madrid, Spain. Patients or participants : 280 patients with C-ARDS, not requiring IMV on admission. Interventions None. Main variables of interest : Target: endotracheal intubation and IMV, mortality. Predictors: demographics, hourly evolution of oxygenation, clinical data, and laboratory results. Results The time between symptom onset and ICU admission, the APACHE II score, the ROX index, and procalcitonin levels in blood were potential predictors related to both IMV and mortality. The ROX index was the most significant predictor associated with IMV, while APACHE II, LDH, and DaysSympICU were the most with mortality. Conclusions According to the results of the analysis, there are significant predictors linked with IMV and mortality in C-ARDS patients, including the time between symptom onset and ICU admission, the severity of the COVID-19 waves, and several clinical and laboratory measures. These findings may help clinicians to better identify patients at risk for IMV and mortality and improve their management. (AU)

Objetivo Determinar si las variables clínicas independientes que condicionan el inicio de ventilación mecánica invasiva (VMI) son los mismos que condicionan la mortalidad en el síndrome de distrés respiratorio agudo asociado con COVID-19 (C-SDRA). Diseño Estudio observacional longitudinal en un solo centro. Ámbito UCI, hospital terciario: primeras dos olas de COVID-19 en Madrid, España. Pacientes o participantes 280 pacientes con C-SDRA que no requieren VMI al ingreso en UCI. Intervenciones Ninguna. Principales variables de interés Objetivo: VMI y Mortalidad. Predictores: demográficos, variables clínicas, resultados de laboratorio y evolución de la oxigenación. Resultados El tiempo entre el inicio de los síntomas y el ingreso en la UCI, la puntuación APACHE II, el índice ROX y los niveles de procalcitonina en sangre eran posibles predictores relacionados tanto con la IMV como con la mortalidad. El índice ROX fue el predictor más significativo asociada con la IMV, mientras que APACHE II, LDH y DaysSympICU fueron los más influyentes en la mortalidad. Conclusiones Según los resultados obtenidos se identifican predictores significativos vinculados con la VMI y mortalidad en pacientes con C-ARDS, incluido el tiempo entre el inicio de los síntomas y el ingreso en la UCI, la gravedad de las olas de COVID-19 y varias medidas clínicas y de laboratorio. Estos hallazgos pueden ayudar a los médicos a identificar mejor a los pacientes en riesgo de IMV y mortalidad y mejorar su manejo. (AU)