Using initial serum lactate level in the emergency department to predict the sustained return of spontaneous circulation in nontraumatic out-of-hospital cardiac arrest patients

Ar-aishah Dadeh, Banjaparat Nuanjaroan Department of Emergency Medicine, Songklanagarind Hospital, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand Objective: To examine the initial level of lactate to predict sustained return of spontaneous circulation (ROSC) in nontraumatic out-of-hospital cardiac arrest (OHCA) patients. Materials and methods: This was a 30-month retrospective cohort study in an emergency department (ED) of a tertiary care hospital. The inclusion criteria were adult nontraumatic OHCA patients who came to the ED with ongoing chest compression. The primary outcome was initial serum lactate level at the ED to predict sustained ROSC in nontraumatic OHCA. Logistic regression was used to determine any association between sustained ROSC and significant variables. Results: There were 207 patients who met the inclusion criteria. Forty one percent of nontraumatic OHCA patients achieved sustained ROSC. The mean ± SD initial serum lactate in the ROSC group was lower than the non-ROSC group (12.0±4.8 vs 12.6±5), but without statistical significance. The significant factors to predict sustained ROSC were no underlying disease (adjusted odds ratio [aOR] 1.71, 95% CI 0.51–5.71, P=0.014), cardiac arrest in a public area (aOR 2.40, 95% CI 1.2–4.79, P=0.013), and witnessed arrest (aOR 2.39, 95% CI 1.26–4.52, P=0.008). The cut-off points of initial serum lactate to predict mortality at 24 and 48 hours after cardiopulmonary resuscitation were 9.1 (P=0.031) and 9.4 (P=0.049) mmol/L, respectively. Eleven survived to hospital discharge, and 54.5% had good neurological outcome without statistical significance (P=0.553). The significant variables and initial lactate levels were used to develop a scoring system which ranged from –4 to 11. The receiver operating characters curve indicated a cut-off point of 3.6 to predict ROSC with an area under the curve of 0.715. Conclusion: The initial serum lactate had no association with sustained ROSC and hospital discharge with good neurological outcome but can be used to predict 24- and 48-hour postresuscitation mortality in nontraumatic OHCA patients with initial serum lactate cut-off points of 9.1 and 9.4 mmol/L, respectively. Keywords: out-of-hospital cardiac arrest, initial serum lactate, sustained return of spontaneous circulatio