Objective To evaluate the efficacy and safety of potassium replacement infusions in critically ill patients.
Design Prospective cohort study.
Setting Multidisciplinary critical care unit.
Patients Forty-eight critically ill adult patients, age 25 to 86 yrs. Patients entered the study when hypokalemia (potassium <3.5 mmol/L) was noted on routine laboratory blood analysis. Most common primary diagnoses on ICU admission included postoperative cardiac surgery (n = 9), sepsis and multiple organ system failure (n = 9), complicated myocardial infarction (n = 7), and respiratory failure (n = 5).
Intervention Potassium chloride infusions (20,30, or 40 mmol in 100 mL normal saline over 1 hr) were administered to patients for serum potassium levels of <3.5 but >3.2 mmol/L (n = 26), 3.0 to 3.2 mmol/L (n = 11), and <3.0 mmol/L (n = 11), respectively. Serum and urine potassium levels were monitored during and for 1 hr after the infusion.
Measurements and Results All patients tolerated the infusions without evidence of hemodynamic compromise, ECG change, or new dysrhythmia requiring treatment. The mean maximum potassium increase was 0.5 ± 0.3 mmol/L, 0.9 ± 0.4 mmol/L, and 1.1 ± 0.4 mmol/L in the 20-, 30-, and 40-mmol groups, respectively. The increase in serum potassium was maximal at the completion of the infusion and was significant (p < .05) compared with baseline in all groups. Peak potassium levels were the same in patients with normal renal function (n = 33) compared with those with renal insufficiency (n = 15).
Urinary excretion of potassium increased in all groups during the infusion and was significant (p < .05) in the 30− and 40-mmol groups, but was no greater in those patients who had received diuretics (n = 8) compared with those patients who had not (n = 40).
Conclusions In the select group of hypokalemic patients studied, potassium infusions of 20 to 40 mmol delivered over 1 hr were safe to administer and effectively increased serum potassium levels in a dosedependent and predictable fashion. Furthermore, these results were independent of the patient's underlying renal function or associated diuretic administration. (Crit Care Med 1991; 19:694)
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