Abstract Sa503: Serum lactate/albumin ratio at hospital arrival and neurological outcome of patients 30 days after the occurrence of out-of-hospital cardiac arrest: a nationwide multicenter observational study

Background: Previous studies have shown that a lower serum lactate/albumin ratio was positively correlated with the survival of severely ill patients, such as those with septic shock, in critical care. However, there is limited knowledge regarding the association between the serum lactate/albumin ratio and neurological outcome in patients with out-of-hospital cardiac arrest. Thus, we investigated whether a lower serum lactate/albumin ratio at hospital arrival was associated with good neurological outcomes in such patients. Methods: This was a multicenter observational study using data from The Japanese Association for Acute Medicine out-of-hospital cardiac arrest Registry. We reviewed records of patients aged ≥18 years with out-of-hospital cardiac arrest of medical etiology and hospitalized after return of spontaneous circulation, with serum lactate and albumin levels recorded at hospital arrival, between June 1, 2014 and December 31, 2021. The medical etiology excluded trauma, drowning, poisoning, burns, asphyxia, or hanging. We excluded cases with missing data, patients who were treated with extracorporeal membrane oxygenation, and those for whom the time period from the emergency call to the measurement of laboratory data was >120 mins. The primary outcome was 30-day survival with good neurological outcome, defined as cerebral performance category scale 1 or 2. Analyzed patients were divided into quartiles based on the serum lactate/albumin ratio. Multivariable logistic regression analysis was performed to adjust for several factors. Results: We analyzed 5,016 patients. The proportions of good neurological outcome were 56.0% (709/1,267), 27.9% (348/1,246), 11.3% (142/1,253), and 2.8% (35/1,250) in the first (serum lactate/albumin ratio ≤ 2.06), second (2.06 < serum lactate/albumin ratio ≤ 3.24), third (3.24 < serum lactate/albumin ratio ≤ 4.59), and fourth (4.59 < serum lactate/albumin ratio) quartiles, respectively. The multivariable logistic regression analysis showed that the adjusted odds ratio (95% confidence interval) values for good neurological outcome in the second, third, and fourth quartiles, compared with the first quartile, were 0.34 (0.28–0.42), 0.19 (0.15–0.25), and 0.06 (0.04–0.08), respectively. Conclusions: In the Japanese national registry, a lower serum lactate/albumin ratio at hospital arrival was significantly associated with good neurological outcome in patients with out-of-hospital cardiac arrest.