Truncal rigidity as a result of epidural sufentanil--a case report

It is well known that intravenous opioids may cause truncal rigidity. To the best of our knowledge truncal rigidity induced by epidural opioid has never been reported. Recently, we came across an accident of truncal rigidity following epidural sufentanil. The victim was a 65-year-old female who received cholecystectomy, choledochotomy, and cholangiography. For post-operative pain control, an epidural catheter was inserted cephalad [corrected] at L1-2 interspace with a length of 4 cm of the catheter retained in the epidural space. The epidural catheter was secured and tested for correct placement with 3 ml of 2% lidocaine with 1:200,000 epinephrine prior to induction of general anesthesia. No opioid was ever given in the operative course. When the patient was fully awake and complained of wound pain in the recovery room 50 mg of sufentanil in 10 ml normal saline was given via the epidural catheter after a negative evacuation test. About one minute after the epidural shot, she was found to lose consciousness without any slightest warning sign. Truncal rigidity and locked jaw that followed entailed respiratory arrest and rapid deterioration of oxygenation which evidenced a life-threatening airway emergency. It spite of our efforts we could not manage to ventilate her with ordinary means. It was not until the administration of 80 mg of succinylcholine and oral endotracheal intubation could an adequate ventilation be reestablished. She regained spontaneous breathing 15 min after the episode but for safety's sake she remained intubated for 6 h until the dissipation of analgesia. Another test dose was attempted, which reconfirmed that the epidural catheter was in proper position. She stayed in the recovery room for 24 h and returned to ward in satisfactory condition. The incidence disclosed that epidural sufentanil even with a dose as small as 50 micrograms could cause truncal rigidity. Thus when epidural sufentanil is applied for post-operative pain control constant vigilance is necessary in order to avoid accident.