Nonmalignant hyperthermia on induction of anesthesia in a pediatric patient undergoing bidirectional Glenn procedure.

We report a case of severe hyperthermia in a 6-month-old boy with a single ventricle, dextrocardia, asplenia, and transposition of the great arteries, during induction of anesthesia on three separate occasions. To our knowledge, this is the first case reported of repeated intraoperative hyperthermia not related to malignant hyperthermia, infection, neuroendocrine tumor, or iatrogenic causes (e.g., anticholinergic blockade or warming devices). The severe hyperthermia may be secondary to the medications given before and during induction and/or the stress of the induction. Among the induction medications given during the three episodes, fentanyl is the most likely contributing drug. Human data indicate that opioids increase the sweating threshold and decrease the vasoconstriction and shivering thresholds. The medications could cause a widening in the thermoregulation interthreshold and the stress could induce nonshivering thermogenesis.