Abstract 133: Relation Between Initial Arterial Blood pH Levels and Neurological Outcomes in Patients Treated With Hypothermia After Out-of-Hospital Cardiac Arrest: J-PULSE-Hypo Registry
Background: Therapeutic hypothermia (TH) has been shown to improve neurologic recovery in comatose patients after out-of-hospital cardiac arrest (OHCA). However, the indications for TH remain controversial. We aimed to determine whether arterial blood gas data evaluated on emergency department (ED) arrival is useful for predicting neurologic outcomes in patients with TH.
Methods: We analyzed data from the J-PULSE-Hypo registry, a multicenter, observational study using Utstein templates in patients with TH from January 2005 through December 2009. We included 210 patients with witnessed arrest and arterial blood sampling within 30 minutes after ED arrival and within 60 minutes after collapse. Clinical outcomes were assessed on the basis of cerebral performance categories (CPC).
Results: The 210 eligible patients (164 men, median age 61 years) were divided into the good recovery (GR) group (N=121) with CPC 1–2 and the non-good recovery (non-GR) group (N=89) with CPC 3–5 according to the neurologic outcomes at discharge from the hospital. As compared with the non-GR group, the GR group had a significantly younger age; higher rates of ventricular fibrillation as initial rhythm and return of spontaneous circulation (ROSC) at ED arrival; a shorter time from collapse to ROSC; higher levels of hemoglobin, HCO3, base excess (BE), and pH; and lower levels of glucose and PaCO2 (p<0.01). A multiple logistic-regression model using significant variables on bivariate analysis showed that neurologic outcomes were significantly (p<0.05) related to pH level with an odds ratio of 1.564 (degrees of freedom, 0.1) (95% CI, 1.241–1.971), age with an odds ratio of 0.970 (95% CI, 0.943–0.998) and the rate of ROSC at hospital arrival with an odds ratio of 2.276 (95% CI, 1.100–4.710). Receiver operating characteristic (ROC) curve showed the pH level cutoff value of 7.095 with a sensitivity of 72.7% and a specificity of 74.2% (AUC=0.771, p<0.01) for identification of a favorable neurological outcome.
Conclusions: The pH level can be a useful predictor of neurological outcomes in patients with TH after OHCA. Therefore, it is important that arterial blood gas data are evaluated after ED arrival as soon as possible for clinical decision of TH.
- © 2010 by American Heart Association, Inc.