Cardiac Medications Are Not Associated with Clinically Important Preoperative Electrolyte Disturbances in Children Presenting for Cardiac Surgery

Abstract

Preoperative laboratory examination of patients undergoing elective surgical procedures has been routinely performed for decades. Although there is a large body of literature concerning the appropriate preoperative assessment of adult patients, corresponding literature for the pediatric population is not as well defined. Children and young adults with cardiac disease are a particularly vulnerable subset of patients who often undergo an extensive battery of preoperative laboratory testing. We examined the serum chemistry profiles for children with cardiac disease presenting for outpatient surgery. The investigation aims to define the effectiveness of preoperative electrolyte determination in this population of children and young adults. A retrospective chart review of all children presenting as outpatients to a tertiary care, freestanding children's hospital for elective cardiac surgery between January 1, 2000 and January 31, 2003 was performed. All patient charts in which the admission date matched the cardiac surgical date were examined. Patients were excluded if the preoperative laboratory evaluation was performed outside of our facility, preoperative laboratory investigation was not performed, or the patient was transported by medical transport to our hospital. Patients were grouped according to three methods: the number of cardiac medications (none to four), and cardiac medications, noncardiac medications, and no medications. The presence of electrolyte abnormalities was also examined in the context of cardiac medications with various pharmacologic effects. The primary outcome measure was the incidence of abnormal laboratory values for children taking various cardiac medications. Of the 933 initial entries found, 774 met the investigational criteria and were included in the analysis. Although statistically significant differences in preoperative electrolytes were associated with the use of cardiac and noncardiac medication, there was no clinical value to this correlation. The data demonstrate a very low incidence of hypokalemia and hypomagnesemia in the entire study population. Preoperative electrolyte disturbances in children and young adults presenting for cardiac surgery are uncommon. The concern of hypokalemia or hypomagnesemia important in the adult population taking cardiac medications was not identified in the pediatric population. These data do not support the need for routine preoperative electrolyte evaluation in children taking cardiac medications.