Factors associated with a nonresponse to prone positioning in patients with severe acute respiratory distress syndrome due to SARS-CoV-2.

OBJECTIVE: To identify risk factors for nonresponse to prone positioning in mechanically ventilated patients with COVID-19-associated severe acute respiratory distress syndrome and refractory hypoxemia in a tertiary care hospital in Colombia. METHODS: Observational study based on a retrospective cohort of mechanically ventilated patients with severe acute respiratory distress syndrome due to SARS-CoV-2 who underwent prone positioning due to refractory hypoxemia. The study considered an improvement ≥ 20% in the PaO2/FiO2 ratio after the first cycle of 16 hours in the prone position to be a 'response'. Nonresponding patients were considered cases, and responding patients were controls. We controlled for clinical, laboratory, and radiological variables. RESULTS: A total of 724 patients were included (58.67 ± 12.37 years, 67.7% males). Of those, 21.9% were nonresponders. Mortality was 54.1% for nonresponders and 31.3% for responders (p < 0.001). Variables associated with nonresponse were time from the start of mechanical ventilation to pronation (OR 1.23; 95%CI 1.10 - 1.41); preintubation PaO2/FiO2 ratio (OR 0.62; 95%CI 0.40 - 0.96); preprone PaO2/FiO2 ratio (OR 1.88. 95%CI 1.22 - 2.94); and radiologic multilobe consolidation (OR 2.12; 95%CI 1.33 - 3.33) or mixed pattern (OR 1.72; 95%CI 1.07 - 2.85) compared with a ground-glass pattern. CONCLUSION: This study identified factors associated with nonresponse to prone positioning in patients with refractory hypoxemia and acute respiratory distress syndrome due to SARS-CoV-2 receiving mechanical ventilation. Recognizing such factors helps identify candidates for other rescue strategies, including more extensive prone positioning or extracorporeal membrane oxygenation. Further studies are needed to assess the consistency of these findings in populations with acute respiratory distress syndrome of other etiologies.

Factors associated with a nonresponse to prone positioning in patients with severe acute respiratory distress syndrome due to SARS-CoV-2 / Fatores associados ao paciente com síndrome do desconforto respiratório agudo grave devido ao SARS-CoV-2 irresponsivo ao decúbito ventral

ABSTRACT Objective: To identify risk factors for nonresponse to prone positioning in mechanically ventilated patients with COVID-19-associated severe acute respiratory distress syndrome and refractory hypoxemia in a tertiary care hospital in Colombia. Methods: Observational study based on a retrospective cohort of mechanically ventilated patients with severe acute respiratory distress syndrome due to SARS-CoV-2 who underwent prone positioning due to refractory hypoxemia. The study considered an improvement ≥ 20% in the PaO2/FiO2 ratio after the first cycle of 16 hours in the prone position to be a 'response'. Nonresponding patients were considered cases, and responding patients were controls. We controlled for clinical, laboratory, and radiological variables. Results: A total of 724 patients were included (58.67 ± 12.37 years, 67.7% males). Of those, 21.9% were nonresponders. Mortality was 54.1% for nonresponders and 31.3% for responders (p < 0.001). Variables associated with nonresponse were time from the start of mechanical ventilation to pronation (OR 1.23; 95%CI 1.10 - 1.41); preintubation PaO2/FiO2 ratio (OR 0.62; 95%CI 0.40 - 0.96); preprone PaO2/FiO2 ratio (OR 1.88. 95%CI 1.22 - 2.94); and radiologic multilobe consolidation (OR 2.12; 95%CI 1.33 - 3.33) or mixed pattern (OR 1.72; 95%CI 1.07 - 2.85) compared with a ground-glass pattern. Conclusion: This study identified factors associated with nonresponse to prone positioning in patients with refractory hypoxemia and acute respiratory distress syndrome due to SARS-CoV-2 receiving mechanical ventilation. Recognizing such factors helps identify candidates for other rescue strategies, including more extensive prone positioning or extracorporeal membrane oxygenation. Further studies are needed to assess the consistency of these findings in populations with acute respiratory distress syndrome of other etiologies.

RESUMO Objetivo: Identificar fatores de risco em pacientes submetidos à ventilação mecânica devido à síndrome do desconforto respiratório agudo grave associada à COVID-19 e hipoxemia refratária irresponsivos ao decúbito ventral em um hospital terciário na Colômbia. Métodos: Estudo observacional baseado em coorte retrospectiva de pacientes submetidos à ventilação mecânica devido à síndrome do desconforto respiratório agudo grave associada ao SARS-CoV-2 em decúbito ventral devido à hipoxemia refratária. O estudo considerou resposta a melhora ≥ 20% na relação entre pressão parcial de oxigênio e fração inspirada de oxigênio após o primeiro ciclo de 16 horas em decúbito ventral. Os pacientes irresponsivos foram considerados casos, e os responsivos foram considerados controles. Controlamos as variáveis clínicas, laboratoriais e radiológicas. Resultados: Foram incluídos 724 pacientes (58,67 ± 12,37 anos, 67,7% do sexo masculino). Destes, 21,9% eram pacientes irresponsivos. A mortalidade foi de 54,1% nos irresponsivos e de 31,3% nos responsivos (p < 0,001). As variáveis associadas à ausência de resposta foram tempo do início da ventilação mecânica até o decúbito ventral (RC de 1,23; IC95% 1,10 - 1,41); relação entre pressão parcial de oxigênio e fração inspirada de oxigênio pré-intubação (RC de 0,62; IC95% 0,40 - 0,96); relação entre pressão parcial de oxigênio e fração inspirada de oxigênio anterior ao decúbito ventral (RC de 1,88; IC95% 1,22 - 2,94); e consolidação radiológica de múltiplos lobos (RC de 2,12; IC95% 1,33 - 3,33) ou padrão misto (RC de 1,72; IC95% 1,07 - 2,85) em comparação com um padrão em vidro fosco. Conclusão: Este estudo identificou fatores associados à ausência de resposta ao decúbito ventral em pacientes com hipoxemia refratária e síndrome do desconforto respiratório agudo devido ao SARS-CoV-2 em ventilação mecânica. O reconhecimento desses fatores ajuda a identificar os candidatos a outras estratégias de resgate, incluindo decúbito ventral mais prolongado ou oxigenação por membrana extracorpórea. São necessários novos estudos para avaliar a consistência desses achados em populações com síndrome do desconforto respiratório agudo por causa de outras etiologias.