Abstract 249: Impact Of Partial Pressure Of Carbon Dioxide On Survival And Neurologic Outcomes In In-hospital Cardiac Arrest Patients

Abstract

Background: As cardiac arrest remains an event associated with high morbidity and mortality, interventions to mitigate neurologic injury and improve survival in these patients is an area of ongoing research. As carbon dioxide levels play an important role in cerebral vascular regulation, targeting a specific partial pressure of carbon dioxide (PaCo2) is a potential therapeutic intervention in cardiac arrest care. Our study aims to determine the impact of PaCo2 on survival and neurologic outcomes in in-hospital cardiac arrest (IHCA) patients. Methods: This study is a single center prospective observational study. The population included IHCA patients from August 2011 to July 2021. Arterial blood gas data (ABG) was available for 154 patients intra cardiac arrest and 336 patients in the post ROSC period. PaCo2 levels from the ABG data where subdivided into different ranges including hypocapnia (PaCo2 <35mm Hg), normocapnia (35-45 mm Hg) and hypercapnia (>45mmHg). The primary outcomes of interest were survival to hospital discharge and neurologic outcome. Results: Analysis of the PaCo2 data demonstrated that intra arrest PaCo2 was not associated with survival to discharge (p value 0.129). Mild hypercapnia (PaCO2 46-54 mmHg) and moderate hypercapnia (55-79mmHg) intra arrest were associated with favorable neurologic outcomes (p value 0.039). A univariate analysis of post ROSC ABG data demonstrated that normocapnia was associated with survival to discharge (p value <0.001) and favorable neurologic outcomes (p value 0.05). Similar findings were seen in two multivariate analyses examining the association of PaCo2 with survival and neurologic outcome. The multivariate analysis examining survival showed that hypocapnia and hypercapnia were associated with a higher mortality compared to normocapnia (p values 0.016 and <0.001). In the multivariate analysis examining neurologic outcomes, hypercapnia was associated with worse neurologic outcome when compared to normocapnia (p value 0.004). Conclusions: Post ROSC, normocapnia was associated with favorable neurologic outcomes and survival to discharge. Our study supports targeting normocapnia in the post cardiac arrest period.