The clinical relevance of plasma potassium abnormalities on admission in trauma patients: a retrospective observational study

BACKGROUND Abnormalities in potassium levels can lead to several clinical difficulties in trauma patients admitted to the ICU. However, the significance of potassium abnormalities soon after admission in trauma patients has not yet been clearly delineated. The objective of this study was to describe the plasma potassium abnormalities in trauma patients on admission and to examine the clinical outcomes associated with these abnormalities. METHODS We performed a retrospective observational study of plasma potassium levels in trauma patients admitted to the Fukuyama City Hospital between January 1, 2010 and December 31, 2013. Five hundred twenty consecutive trauma patients were included and categorized into six groups according to their plasma potassium level on admission (<3.0, 3.0-<3.5, 3.5-<4.0, 4.0-<4.5, 4.5-<5.0, and ≥5.0 mEq/L). After adjusting for covariates, including age, gender, the Revised Trauma Score, and the Injury Severity Score, logistic regression analysis was used to examine the association between plasma potassium levels and outcomes, including life-saving interventions and in-hospital mortality. RESULTS Two hundred twenty-seven patients (43.7 %) presented with hypokalemia (<3.5 mEq/L), while seven patients (1.3 %) presented with hyperkalemia (≥5.0 mEq/L). Patients in the lowest potassium group (<3.0 mEq/L, n = 36 [6.9 %]) were significantly associated with craniotomy (adjusted odds ratio 5.25 [95 % confidence interval 2.06-13.40]; p < 0.001) and showed an increased trend toward in-hospital mortality. In the second lowest potassium group (3.0-< 3.5 mEq/L, n = 191 [36.7 %]), the adjusted odds ratio for craniotomy was significantly higher (2.03 [95 % confidence interval 1.01-4.07]; p = 0.048) compared to the reference group. CONCLUSIONS Trauma patients presenting with hypokalemia (<3.5 mEq/L) on admission may be associated with severe head trauma requiring life-saving craniotomy.