Pilot study of preoperative heart rate variability and adverse events in children emerging from anesthesia.

OBJECTIVE

To assess correlations between preoperative heart rate variability (a noninvasive measure of autonomic cardiac activity) and adverse respiratory events during anesthesia emergence in children.

DESIGN

Case control study.

SETTING

Tertiary care pediatric operating room.

PATIENTS

Sixty-one children, aged 8 months to 13 yrs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate power spectra were obtained from two 5-min immediate-preoperative electrocardiographs with an orthostatic posture change interposed and (n = 32) from a 24-hr preoperative Holter monitor. Observers recorded emergence from standardized anesthesia for coughing, laryngospasm, and desaturation. Low-frequency/high-frequency ratios (LF/HF) were derived from power spectra of heart rate variability. The orthostatic change in heart rate variability derived from brief preoperative recordings was significantly different if adverse events occurred during emergence from anesthesia (LF/HF standing/LF/HF supine = 1.3 vs. 2.8, p = .019). Holter-derived heart rate variability had no correlation with adverse events. Receiver operating characteristic analysis showed a sensitivity of 85% and specificity of 52% for predicting adverse events with preoperative recordings.

CONCLUSIONS

This study provides new information regarding pathophysiology in children with upper respiratory infection. The magnitude of difference demonstrated is insufficient to propose this method as a preoperative screening test.