Delayed muscular rigidity and respiratory depression following fentanyl anesthesia
J. M. Klausner, J. Caspi, S. Lelcuk, A. Khazam, G. Marin, H. B. Hechtman and R. R. Rozin
Department of Surgery, Hadassah (Rokach) Hospital, Tel Aviv Medical Center, Tel Aviv University, Israel.
A delayed effect of fentanyl used for anesthesia may be respiratory
distress several hours after surgery. The findings are muscular rigidity,
fall in chest wall compliance, hypoventilation, respiratory acidosis, and
hypotension. In the past, to our knowledge, this complication was
exclusively reported in patients undergoing cardiac surgery, when large
fentanyl dosages are employed. This article describes three general
surgical patients in whom respiratory distress developed three to five
hours following colon surgery when a moderate dose of fentanyl citrate, 55
to 75 micrograms/kg, was used. Initially, all patients had a normal
recovery from anesthesia. Later, respiratory distress was successfully
treated with a fentanyl antagonist and ventilatory assistance. This delayed
toxic phenomenon is thought to be due to the reentry of fentanyl into
plasma from deposits in adipose tissue, muscle, and the gastrointestinal
tract, leading to a secondary rise in the plasma concentration. It is more
likely to be encountered when hypothermia, rewarming, and acidosis are
present in the postoperative period. This life-threatening complication is
treacherous, since it may occur when the patient has been transferred to
the surgical ward and is less closely monitored.
