Abstract 348: Impact of Low and High Partial Pressure of Carbon Dioxide on Neuron Specific Enolase Derived from Serum and Cerebrospinal Fluid in Patients Who Underwent Targeted Temperature Management After Out-of-hospital Cardiac Arrest: A Retrospective Study

Abstract

Aim: In a previous study, low and high-normal arterial carbon dioxide tension (PaCO 2 ) were not associated with serum neuron specific enolase (NSE) in cardiac arrest survivors. We assessed the effect of PaCO 2 on NSE in cerebrospinal fluid (CSF) and serum. Methods: This was a retrospective study. PaCO 2 for the first 24 h was analysed in four means, qualitative exposure state (qES), time-weighted average (TWA), median, and minimum-maximum (Min-Max). These subgroups were divided into low (LCO 2 ) and high PaCO 2 (HCO 2 ) groups defined as PaCO 2 ≤35.3 and PaCO 2 >43.5 mmHg, respectively. NSE was measured at 24, 48, and 72 h (sNSE 24,48,72 and cNSE 24,48,72 ) from return of spontaneous circulation (ROSC). The primary outcome was the association between PaCO 2 and the NSE measured at 24 h after ROSC. Results: Forty-two subjects (male, 33; 78.6%) were included in total cohort. PaCO 2 in TWA subgroup was associated with cNSE 24,48,72 , while PaCO 2 in the other subgroup were only associated with cNSE 24 . PaCO 2 and cNSE in qES subgroup showed good correlation (r= -0.61; p< 0.01), and in TWA, Median, and Min-Max subgroup showed moderate correlations (r= -0.57, r= -0.48, and r= -0.60; p< 0.01). Contrastively, sNSE was not associated and correlated with PaCO 2 in all analysis. Poor neurological outcome in LCO 2 was significantly higher than HCO 2 in qES, TWA, and Median subgroups ( p< 0.01, p< 0.01, and p= 0.02). Conclusion: Association was found between NSE and PaCO 2 using CSF, despite including normocapnic ranges; TWA of PaCO 2 may be most strongly associated with CSF NSE levels. A prospective, multi-centre study is required to confirm our results.