Laboratory Abnormalities in Patients in the Medical Intensive Care Unit

Objective: The goals of this article are to (1) identify the incidence of reported laboratory abnormalities in patients in the medical intensive care unit (ICU); (2) characterize the relationship between reported laboratory abnormalities and Acute Physiology and Chronic Health Evaluation III (APACHE III) score, length of stay, and mortality; and (3) evaluate therapeutic replacement in patients with electrolyte abnormalities. Design: Retrospective chart review of all patients admitted to the medical ICU between April 1, 1993 and June 30, 1993. Setting: Large teaching institution. Participants: Patients admitted to the medical ICU (n = 116). Interventions: The following data were collected: age, sex, admitting diagnosis, serum electrolyte and laboratory parameters, APACHE HI score, length of ICU stay, and mortality. Results: Ten individual laboratory abnormalities were found in more than 30% of all patients in the medical ICU (range 32.8–59.5%). Abnormalities in four laboratory parameters were associated with undesirable patient outcomes. Patients with hypoalbuminemia had a significantly higher APACHE HI score (p < 0.05). Hypocalcemia, hypomagnesemia, and hypoalbuminemia all were associated with an increased length of stay in the ICU (p < 0.05). Overall mortality was significantly higher in patients with alkalosis (p = 0.002). Therapeutic replacement in those with low electrolyte concentrations often was delayed or missed. Fifteen to 75% of patients who had abnormally low serum electrolyte concentrations were not treated. Conclusions: A high incidence of laboratory abnormalities is reported in patients admitted to the medical ICU. Several of these abnormalities are associated with undesirable outcomes such as an increased length of ICU stay in patients with hypoalbuminemia, hypocalcemia, and hypomagnesemia and increased mortality in patients with alkalosis. Therapeutic replacement of electrolytes in patients with abnormalities often was delayed or missed.