Oh Sheow Boon, MBBS
Medical Student
Lee Kong Chian School of Medicine, Slovenia
Disclosure information not submitted.
Apollo Aguilan, ART, BSc, RRT
Respiratory Therapist
KK Women’s and Children’s Hospital, Singapore
Disclosure information not submitted.
Lee Jan Hau, MBBS, MRCPCH, MCI (he/him/his)
KK Women's and Children's Hospital, Singapore
Singapore, Slovenia
Disclosure information not submitted.
Judith, Ju-Ming Wong, MBBCh, BAO, MRCPCH
Consultant
Children's Intensive Care Unit, KK Women's and Children's Hospital, United States
Disclosure information not submitted.
Title: Alveolar Dead Space Fraction Predicts Mortality in Pediatric Acute Respiratory Distress Syndrome
Introduction: Acute Respiratory Distress Syndrome (ARDS) is known to be associated with high mortality. Alveolar dead-space fraction (AVDSF), the volume of alveolar gas that does not participate in gas exchange, has been reported to predict mortality and morbidity in ARDS in the adult population. The goal of this study is to characterize AVDSF in pediatric ARDS (PARDS) and to determine its association with clinical outcomes such as mortality.
Methods: This is a post-hoc analysis utilizing data from a before-and-after study of a lung protective mechanical ventilation protocol. All mechanically ventilated patients fulfilling the Pediatric Acute Lung Injury Consensus Conference (PALICC) criteria for PARDS were recruited from June 2018 to April 2021. AVDSF was calculated by the difference between arterial partial pressure of carbon dioxide (PaCO2) and end-tidal carbon dioxide (etCO2), using the equation: AVDSF=(PaCO2 – etCO2)/PaCO2. Pearson’s correlation was used to determine the correlation between PaCO2 and etCO2, and of AVDSF and Oxygenation Index (OI). T-test was used to compare AVDSF between PARDS severity groups and survivors/non-survivors. Receiver Operating Characteristic (ROC) regression analysis was used to determine the predictive value of AVDSF on mortality, after adjusting for OI.
Results: A total of 196 etCO2 and PaCO2 comparisons from 43 PARDS patients [mean (standard deviation) age 6.3 (+/-5.2) years] were included in this analysis. PaCO2 was expectedly higher than etCO2 [47.9 (+/-16.6) vs. 41.9 (+/-12.8) mmHg; p< 0.001] with strong correlation [r=0.78 (p < 0.001)]. Mean AVDSF was observed to increase with increasing PARDS severity: at-risk [0.12 (+/-0.11)], mild [0.14 (+/-0.12)], moderate [0.16 (+/-0.11)] and severe [0.29 (+/-0.16); p=0.024]. AVDSF was higher in non-survivors [0.23(+/-0.11) vs. 0.15 (+/-0.13); p=0.024] compared to survivors; with ROC regression Area Under Curve of 0.75.
Conclusion: AVDSF was associated with greater severity of lung injury in PARDS and was an independent predictor of mortality in PARDS.