Rigidity and hypercarbia associated with high dose fentanyl induction of anesthesia.

To the Editor: We would like to report our recent experience regarding truncal rigidity after large doses of intravenous fentanyl. The occurrence of rigidity with large dose intravenous fentanyl has been a controversial subject. Stanley and Webster (1) reported no rigidity or difficulty with ventilation in 23 patients before mitral valve replacement when fentanyl was administered at a rate of 50 to 100 pg/min for the first 4 minutes and 150 to 200 pg/ min thereafter. Holderness at a1 (2) reported 8% of patients became rigid after intravenous administration of 250 to 500 pg of fentanyl. Stoelting et a1 (3) also reported that two of four patients with acquired valvular disease developed rigidity at an infusion rate of 35 pg/min. Corssen et a1 (4) noted that 285 of 359 cases (79%) developed decreased pulmonary compliance after receiving intravenous fentanyl and droperidol. Rigidity varied from slight to total inability to inflate the chest. Giving the drugs separately reduced the frequency of rigidity. In a study by