Impaired Oxygen Delivery Risk Analytics in the 6 Hours Before Extracorporeal Membrane Oxygenation: Single-Center Retrospective Cohort Study in Infants, 2013-2017.

OBJECTIVES

We evaluate the association between pre-extracorporeal membrane oxygenation (ECMO) markers of impaired oxygen delivery, as quantified by the impaired oxygen delivery index (iD o2 ; Etiometry, Boston, MA) and neurologic outcomes in infants supported on ECMO.

DESIGN

A single-center retrospective cohort study using demographic and clinical data along with iD o2 metrics calculated at 120-minute intervals before ECMO initiation. Primary outcomes included mortality, electroencephalography abnormalities, and head imaging findings. The secondary outcomes included brain MRI abnormalities and Functional Status Score (FSS) at discharge.

SETTING

Pediatric ECMO center in North America.

PATIENTS: We included infants younger than 1 year old who were supported on ECMO between 2013 and 2017. We excluded cases with congenital diaphragmatic hernia or postcardiac surgery ECMO.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN

RESULTS

We identified 47 infants meeting the inclusion criteria. Median (interquartile range [IQR]) age and weight at ECMO initiation were 16 days (IQR, 6-112 d) and 3.3 kg (IQR, 2.8-4.8 kg). The overall mortality was 26 of 47 (55% [95% CI, 41-69%]). Nonsurvival compared with survival was associated with a greater proportion of patients with congenital heart disease ( p = 0.03) and pre-ECMO cardiac arrest ( p = 0.006). Time spent above iD o2 thresholds of 25%, 50%, and 75% increased closer to ECMO initiation. Higher iD o2 dose correlated with adverse neurologic outcomes, including electroencephalography abnormalities and abnormal imaging. Last, a logistic regression model for poor outcome (composite of death and FSS), including the time spent above the three iD o2 thresholds at the three time intervals pre-ECMO, showed classification model performance with an area under the receiver operating characteristic curve 0.81 (95% CI, 0.7-0.92; p = 0.0002).

CONCLUSIONS

Markers of impaired oxygen delivery, such as iD o2 in the 6 hours before ECMO are associated with subsequent outcome. Incorporation of these metrics into clinical decision-support systems need to be prospectively tested and evaluated.