Pediatric ARDS phenotypes in critical COVID-19: implications for therapies and outcomes
Authors: Domínguez-Rojas Jesús , Luna-Delgado Yesica , Caqui-Vilca Patrick , Martel-Ramírez Carlos , Quispe-Chipana Miguel , Cruz-Arpi Mario , Atamari-Anahui Noé , Muñoz Ramírez Cleotilde Mireya , Flores Gaudi Quispe , Tello-Pezo Mariela , Cruces Pablo , Vásquez-Hoyos Pablo , Díaz Franco 
Published: June 2022

Purposeto describe lung mechanics in Pediatric Acute Respiratory Disease Syndrome (PARDS) associated with COVID-19. We hypothesize two phenotypes according to respiratory system mechanics and clinical diagnosis.Methodsa concurrent multicenter observational study was performed, analyzing clinical variables and pulmonary mechanics of PARDS associated with COVID-19 in 4 Pediatric intensive care units (PICUs) of Perú. Subgroup analysis included PARDS associated with multisystem inflammatory syndrome in children (MIS-C), MIS-PARDS, and PARDS with COVID-19 primary respiratory infection, C-PARDS. In addition, receiver operator curve analysis (ROC) for mortality was performed.Results30 patients were included. Age was 7.5(4-11) years, 60% male, and mortality 23%. 47% corresponded to MIS-PARDS and 53% to C-PARDS phenotypes. C-PARDS had positive RT-PCR in 67% and MIS-PARDS none (p<0.001). C-PARDS group had more profound hypoxemia (P/Fratio<100, 86%vs38%,p<0.01) and higher driving-pressure (DP) [14(10-22)vs10(10-12)cmH2O], and lower compliance of the respiratory system (CRS)[0.5(0.3-0.6)vs 0.7(0.6-0.8)ml/kg/cmH2O] compared to MIS-PARDS (all p<0.05). ROC-analysis for mortality showed that DP had the best performance [AUC 0.91(95%CI0.81-1.00), with the best cut-point of 15 cmH2O (100% sensitivity and 87% of specificity). Mortality in C-PARDS was 38% and 7% in MIS-PARDS(p=0.09). MV free-days were 12(0-23) in C-PARDS and 23(21-25) in MIS-PARDS(p=0.02)Conclusioncritical pediatric COVID-19 is heterogeneous in children. COVID-19 PARDS had two phenotypes with distinctive pulmonary mechanics features. Characteristics of C-PARDS are like a classic primary PARDS, while a decoupling between compliance and hypoxemia was more frequent in MIS-PARDS. In addition, C-PARDS had fewer MV free-days. DP ≥ 15 cmH2O had the best performance of the quasi-static calculations to discriminate for mortality. Standardized pulmonary mechanics measurements in PARDS might reveal essential information to tailor the ventilatory strategy in pediatric critical COVID-19.‘Take-home message’PARDS associated with COVID-19 have two different phenotypes based on clinical diagnosis and pulmonary mechanics.C-PARDS group was characterized as a classic moderate to severe primary ARDS. A decoupling between compliance and hypoxemia was more frequent in MIS-PARDS. Regarding outcomes, C-PARDS had less VFD and a trend toward higher mortality.Data from the quasi-static calculations were associated with mortality; DP≥ 15 cmH2O was the best discriminator.Standardized pulmonary mechanics measurements in PARDS might reveal essential information to tailor the ventilatory strategy, characterizing different phenotypes and parameters associated with outcomes.TweetLung mechanics help to differentiate two different phenotypes in PARDS associated with COVID-19. C-PARDS associated with respiratory infection, and MIS-PARDS, associated with MIS-C. Also, lung mechanics variables were associated with mortality, being DP ≥ 15 cmH2O the best discriminator.