(716) Respiratory Illnesses Confound Association of Pulmonary Hypertension With Cardiac Arrest Outcomes

Introduction: Pre-existing pulmonary hypertension (PH) is common in children with in-hospital cardiac arrest (IHCA). Surprisingly, PH is not consistently associated with worse outcomes in IHCA studies, possibly due to lack of adjustment for a potential confounder: concurrent respiratory disease. Thus, we leveraged a local database with granular data to test the hypothesis that PH is associated with worse IHCA outcomes after adjusting for respiratory conditions.

Methods: This was a retrospective analysis of prospectively collected data from a single center CA registry including index IHCAs from 2017-2022 in children ≤18yrs. Primary exposure was confirmed/suspected PH based on documentation, echocardiogram, and medications. Outcomes were sustained return of spontaneous circulation (ROSC), return of circulation (ROSC or extracorporeal circulation) (ROC), and survival at hospital discharge (survival). Pre-arrest respiratory diagnoses included bacterial pneumonia, viral bronchiolitis, chronic lung disease (CLD), acute respiratory insufficiency, ARDS, asthma, airway disease, pleural disease, other. We compared diagnoses between groups with Fisher’s exact test. We evaluated PH’s association with outcomes using logistic regression and compared models with and without controlling for respiratory disease using likelihood ratio tests.

Results: Of 259 patients, 55 (21%) had PH. PH subjects were older, more frequently had a primary medical illness (vs surgical) and had more CLD (67% vs 26%, p< 0.01). Adjusted for age and illness category, PH subjects had non-significant decreased odds of ROSC (aOR 0.53, CI95 0.25-1.1, p=0.09) and survival (aOR 0.56, CI95 0.29-1.07, p=0.08), and significant decreased odds of ROC (aOR 0.33, CI95 0.13-0.77, p=0.01). Adjusted for age, illness category, and respiratory diagnoses, PH subjects had significantly decreased odds of ROSC (aOR 0.36, CI95 0.15-0.84, p=0.02), ROC (aOR 0.23, CI95 0.09-0.63, p< 0.01), and survival (aOR 0.43, CI95 0.21-0.91, p=0.03). Models adjusted for respiratory diagnoses better fit the data for all outcomes (p < 0.01).

Conclusions: IHCA with PH had decreased odds of ROSC, ROC, and survival after adjusting for respiratory disease. Future study of PH and other resuscitation topics could benefit from more granularity in IHCA databases to address potential confounders.