Prognosis assessment of strong ion gap in adult patients with cardiac arrest / 中华急诊医学杂志

ABSTRACT

Objective:To investigate the correlation between strong ion gap (SIG) and prognosis of adult hospitalized patients who experienced cardiac arrest (CA).Methods:A retrospective cohort study was conducted on adult CA patients (≥18 years old) who were admitted to the intensive care unit (ICU) for the first time from the Medical Information Mart for Intensive Care Ⅲ (MIMIC-Ⅲ) database from 2001 to 2012. The patients were divided into 3 groups based on the tertiles of serum SIG value. The clinical baseline characteristics and related data of CA patients were compared. Kaplan-Meier method was used to draw the 28- and 90-day cumulative survival curves of CA patients. Meanwhile, the log-rank test was used to compare the differences in the survival curves among different groups, and Cox proportional hazard regression model was established to analyze whether SIG was an independent predictor of all-cause mortality in CA patients.Results:Six hundred and six adult CA patients were eligible for final analysis. The patients were divided into 3 groups based on the tertiles of serum SIG value [<3.91 mmol/L ( n=202), 3.91~7.32 mmol/L ( n=202) and >7.32 mmol/L ( n=202)]. The mean age was (66.91±15.95) years and 382 patients (63.04%) were male. The all-cause mortality rates of ICU, 28 days and 90 days were 36.47%, 49.17% and 56.93%, respectively. There were significant differences in SOFA score, SIG, anion gap, pH, lactic acid, white blood cells, prothrombin time, creatinine, blood potassium, blood phosphorus, hypertension, coronary heart disease, cardiogenic shock, and ICU, 28-day and 90-day all-cause mortality among the 3 groups (all P<0.05). The Kaplan-Meier survival curves showed that the 28- and 90-day cumulative survival rates of CA patients decreased gradually with the increase of SIG level, and the differences were statistically significant among the 3 groups (all P<0.001). Multivariate Cox proportional hazard models showed that the increase of SIG level (>7.32 mmol/L) was an independent risk factor for 28-day ( HR=1.610, 95% CI 1.177-2.203, P=0.003) and 90-day all-cause mortality ( HR=1.506, 95% CI 1.123-2.019, P=0.006) among CA patients, after adjusting for the related confounders. Conclusions:The elevated SIG level (>7.32 mmol/L) is an independent predictor of 28- and 90-day all-cause mortality in CA patients. The calculation of SIG level in these patients is helpful for early identification of patients with poor prognosis.