Characteristics and risk factors associated with mortality during the first cycle of prone secondary to ARDS due to SARS-CoV-2 pneumonia.

OBJECTIVE: To analyze characteristics, changes in oxygenation, and pulmonary mechanics, in mechanically ventilated patients with ARDS due to SARS-CoV-2 treated with prone position and evaluate the response to this maneuver. DESIGN: Cohort study including patients with PaO2/FiO2 <150mmHg requiring prone position over 18 months. We classified patients according to PaO2/FiO2 changes from basal to 24h after the first prone cycle as: 1) no increase 2) increase <25%, 3) 25%-50% increase 4) increase >50%. SETTING: 33-bed medical-surgical Intensive Care Unit (ICU) in Argentina. PATIENTS: 273 patients. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: Epidemiological characteristics, respiratory mechanics and oxygenation were compared between survivors and non-survivors. Independent factors associated with in-hospital mortality were identified. RESULTS: Baseline PaO2/FiO2 was 116 [97-135]mmHg (115 [94-136] in survivors vs. 117 [98-134] in non-survivors; p=0.50). After prone positioning, 22 patients (8%) had similar PaO2/FiO2 values; 46(16%) increased PaO2/FiO2 ≤25%; 55 (21%) increased it 25%-50%; and 150 (55%), >50%. Mortality was 86%, 87%, 72% and 50% respectively (p<0.001). Baseline PaO2/FiO2, <100mmHg did not imply that patients were refractory to prone position. Factors independently associated with mortality were age, percentage increase in PaO2/FiO2 after 24h being in prone, and number of prone cycles. CONCLUSIONS: Older patients unable to improve PaO2/FiO2 after 24h in prone position and who require >1 cycle might early receive additional treatments for refractory hypoxemia. After the first 24h in the prone position, a low percentage of PaO2/FiO2 increase over baseline, beyond the initial value, was independently associated with higher mortality.

[Comparison between the first and second COVID-19 wave of patients who required invasive mechanical ventilation in an intensive care unit in Argentina]. / Comparación entre la primera y segunda ola de pacientes con COVID-19 que requirieron ventilación mecánica invasiva en una unidad de cuidados intensivos de Argentina.

INTRODUCTION: the information regarding characteristics and ventilatory results comparing the first (W1) and the second wave (W2) in Argentina are limited. The main objective of this study was to describe general characteristics and ventilatory variables in COVID-19 patients who required invasive mechanical ventilation (IMV) and compare differences between waves. Secondarily, factors associated with mortality in intensive care unit (ICU) were studied. METHODS: We conducted a prospective observational cohort study that included patients older than 18 years infected with SARS-CoV-2 consecutively admitted to ICU with IMV between August 1, 2020, and June 30, 2021. We included 412 patients. RESULTS: We found statistically significant differences (p < 0.001) in age [W1 64(55-72) vs W2 59 (50-66) years], presence of COPD [W1 n = 42 (19.8%) vs. W2 n = 13(6.3%)], plateau pressure [W1 27(25-30) cm H2O vsW2 24 (22-27) cmH2O], driving pressure (ΔP) [W1 15 (13-17) cmH2O vs. W2 12 (11-14) cm H2O] compliance [W1 40 mL/cmH2O (32-46) vs. W2 = 33 mL/cm H2O (27-40)]; reintubation [W1 30.4% (n = 63/207) vs. W2 13.7% (n = 28/205)]. We identified as independent factors associated with mortality the following variables: age [OR 1.07(95% CI 1.05-1.09)], the ΔP in the first 24 hours [OR 1.19(95% CI 1.10-1.28)] and W2 [OR 1.81 (95% IC1.12-2.93); p = 0.015. DISCUSSION: During W2 the patients were younger. It was possible to achieve ventilatory mechanics more adjusted to a protective ventilation strategy. In conclusion, in the patients studied, age and ΔP were independent predictors of mortality.

Introducción: la información sobre características y resultados ventilatorios que comparen la primera (O1) y segunda (O2) ola de COVID-19 en Argentina son limitados. El objetivo principal de este estudio fue describir las características generales y variables ventilatorias en pacientes COVID-19 que requirieron ventilación mecánica invasiva (VMI) y comparar las diferencias entre olas. Secundariamente se estudiaron factores asociados con mortalidad en la unidad de cuidados intensivos (UCI). Métodos: Realizamos un estudio observacional analítico de cohorte prospectiva que incluyó pacientes mayores de 18 años infectados por SARS-CoV-2 ingresados de forma consecutiva a la unidad de cuidados intensivos, con requerimiento de VMI, entre el 1 de agosto de 2020 y el 30 de junio de 2021. Se incluyeron 412 pacientes. Resultados: Encontramos diferencias estadísticamente significativas (p < 0.001) en: la edad [O1 64 (55-72) años versus O2 59 (50-66) años]; presencia de EPOC [O1 n = 41 (19.8%) versus O2 n = 13 (6.3%)]; Presión meseta [O1 27 (25-30) cmH2O versus O224 (22-27) cmH2O],presión de conducción (ΔP) [O1 15 (13-17) cmH2O versus O2 12 (11-14) cmH2O]; complacencia [O1 40 mL/cmH2O (32-46) versus O2 33 mL/cmH2O (27-40)]; reintubación [O1 30.4% (n=63/207) versus O2 13.7% (n=28/205)]. Se identificaron como factores independientes asociados a mortalidad las siguientes variables: edad [(OR 1.07 (IC 95% 1.05-1.09)], el ΔP en las primeras 24 h [(OR 1.19 (IC 95% 1.10-1.28)] y O2 [OR 1.81 (IC 95% 1.12-2.93); p = 0.015]. Discusión: Durante O2, los pacientes eran más jóvenes. Fue posible lograr una mecánica ventilatoria más ajustada a una estrategia de ventilación protectora. Como conclusión, en los pacientes estudiados la edad y ΔP fueron predictores independientes de mortalidad.

Comparación entre la primera y segunda ola de pacientes con COVID-19 que requirieron ventilación mecánica invasiva en una unidad de cuidados intensivos de Argentina / Comparison between the first and second COVID-19 wave of patients who required invasive mechanical ventilation in an intensive care unit in Argentina

Resumen Introducción: la información sobre características y resultados ventilatorios que comparen la primera (O1) y segunda (O2) ola de COVID-19 en Argentina son limitados. El objetivo principal de este estudio fue describir las características generales y variables ventilatorias en pacientes COVID-19 que requirieron ventilación mecánica invasiva (VMI) y comparar las diferencias entre olas. Secundariamente se es tudiaron factores asociados con mortalidad en la unidad de cuidados intensivos (UCI). Métodos: Realizamos un estudio observacional analítico de cohorte prospectiva que incluyó pacientes mayores de 18 años infectados por SARS-CoV-2 ingresados de forma consecutiva a la unidad de cuidados intensivos, con requerimiento de VMI, entre el 1 de agosto de 2020 y el 30 de junio de 2021. Se incluyeron 412 pacientes. Resultados: Encontramos diferencias estadísticamente significativas (p < 0.001) en: la edad [O1 64 (55-72) años versus O2 59 (50-66) años]; presencia de EPOC [O1 n = 41 (19.8%) versus O2 n = 13 (6.3%)]; Presión meseta [O1 27 (25-30) cmH2O versus O224 (22-27) cmH2O],presión de conducción (ΔP) [O1 15 (13-17) cmH2O versus O2 12 (11-14) cmH2O]; complacencia [O1 40 mL/cmH2O (32-46) versus O2 33 mL/cmH2O (27-40)]; reintubación [O1 30.4% (n=63/207) versus O2 13.7% (n=28/205)]. Se identificaron como factores independientes asociados a mortalidad las siguientes variables: edad [(OR 1.07 (IC 95% 1.05-1.09)], el ΔP en las primeras 24 h [(OR 1.19 (IC 95% 1.10-1.28)] y O2 [OR 1.81 (IC 95% 1.12-2.93); p = 0.015]. Discusión: Durante O2, los pacientes eran más jóvenes. Fue posible lograr una mecánica ventilatoria más ajustada a una estrategia de ventilación protectora. Como conclusión, en los pacientes estudiados la edad y ΔP fueron predictores independientes de mortalidad.

Abstract Introduction: the information regarding characteristics and ventilatory results comparing the first (W1) and the second wave (W2) in Argentina are limited. The main objective of this study was to describe general charac teristics and ventilatory variables in COVID-19 patients who required invasive mechanical ventilation (IMV) and compare differences between waves. Secondarily, factors associated with mortality in intensive care unit (ICU) were studied. Methods: We conducted a prospective observational cohort study that included patients older than 18 years infected with SARS-CoV-2 consecutively admitted to ICU with IMV between August 1, 2020, and June 30, 2021. We included 412 patients. Results: We found statistically significant differences (p < 0.001) in age [W1 64(55-72) vs W2 59 (50-66) years], presence of COPD [W1 n = 42 (19.8%) vs. W2 n = 13(6.3%)], plateau pressure [W1 27(25-30) cm H2O vsW2 24 (22-27) cmH2O], driving pressure (ΔP) [W1 15 (13-17) cmH2O vs. W2 12 (11-14) cm H2O] compliance [W1 40 mL/cmH2O (32-46) vs. W2 = 33 mL/cm H2O (27-40)]; reintubation [W1 30.4% (n = 63/207) vs. W2 13.7% (n = 28/205)]. We identified as independent factors associated with mortality the following variables: age [OR 1.07(95% CI 1.05-1.09)], the ΔP in the first 24 hours [OR 1.19(95% CI 1.10- 1.28)] and W2 [OR 1.81 (95% IC1.12-2.93); p = 0.015. Discussion: During W2 the patients were younger. It was possible to achieve ventilatory mechanics more adjusted to a protective ventilation strategy. In conclusion, in the patients studied, age and ΔP were independent predictors of mortality.