Comparison of the incidence and severity of cough induced by sufentanil and fentanyl: a prospective, randomised, double-blind study : Cough induced by sufentanil and fentanyl

Fentanyl, a synthetic opioid, is a popular choice amongst anesthesiologists in the operating room. Preinduction iv fentanyl bolus is associated with coughing in 28-45% of patients. Coughing due to fentanyl is not always benign and at times may be explosive requiring immediate intervention. We have studied the role of aerosol inhalation of salbutamol, beclomethasone and sodium chromoglycate in preventing fentanyl induced coughing and have compared their efficacy. Two hundred patients aged 18-60 yr, undergoing elective laparoscopic cholecystectomy were randomized into four groups of 50 each. Group I served as control, while Groups II, III and IV received an aerosol inhalation of salbutamol, beclomethasone or sodium chromoglycate 15 min prior to entering the operating room. Following iv fentanyl (2 micro g x kg(-1)) the incidence of cough was recorded and graded as mild (1-2), moderate (3-5) and severe (> 5) depending on the number of coughs observed. Results were analyzed using 'z' and Fischer's Exact test. A P value of /= 0.05). The use of salbutamol, beclomethasone or sodium chromoglycate aerosol 15 min prior to iv fentanyl administration minimizes fentanyl-induced coughing.

Opioid-induced rigidity often makes bag-mask ventilation difficult or impossible during induction of anesthesia. Difficult ventilation may result from chest wall rigidity, upper airway closure, or both. This study further defines the contribution of vocal cord closure to this phenomenon. With institutional review board approval, 30 patients undergoing elective cardiac surgery participated in the study. Morphine (0.1 mg/kg) and scopolamine (6 microg/kg) given intramuscularly provided sedation along with intravenous midazolam as needed. Lidocaine 10% spray provided topical anesthesia of the oropharynx. A fiberoptic bronchoscope positioned in the airway photographed the glottis before induction of anesthesia A second photograph was obtained after induction with 3 microg/kg sufentanil administered during a period of 2 min. A mechanical ventilator provided 10 ml/kg breaths at 10/min via mask and oral airway with jaw thrust. A side-stream spirometer captured objective pulmonary compliance data. Subjective airway compliance was scored. Pancuronium (0.1 mg/kg) provided muscle relaxation. One minute after the muscle relaxant was given, a third photograph was taken and compliance measurements and scores were repeated. Photographs were scored in a random, blinded manner by one investigator. Wilcoxon signed rank tests compared groups, with Bonferroni correction. Differences were considered significant at P < 0.05. Twenty-eight of 30 patients exhibited decreased pulmonary compliance and closed vocal cords after opioid induction. Two patients with neither objective nor subjective changes in pulmonary compliance had open vocal cords after opioid administration. Both subjective and objective compliances increased from severely compromised values after narcotic-induced anesthesia to normal values (P = 0.000002) after patients received a relaxant. Photo scores document open cords before induction, progressing to closed cords after the opioid (P = 0.00002), and opening again after a relaxant was administered (P = 0.00005). Closure of vocal cords is the major cause of difficult ventilation after opioid-induced anesthesia.

To evaluate the minimal dose of lidocaine required for suppression of fentanyl-induced cough. 320 ASA I and II patients, non-smokers of both sexes scheduled for elective surgery between the ages of 18 to 60 yr were randomly allocated into four equal groups. The patients were assigned to receive lidocaine 0.5 mg.kg(-1) (Group I), 1.0 mg.kg(-1)(Group II), 1.5 mg.kg(-1) (Group III) or placebo (Group IV) over five seconds, one minute prior to the administration of fentanyl 3 microg.kg(-1) in a randomized and double-blind fashion. Any episode of cough was classified as coughing and graded as mild (1-2) moderate (3-4) or severe (5 or more). The data were analyzed by test of proportion. Eleven, 12, 11 and 28 patients (13.75%, 15%, 13.75% and 35%) had cough in Groups I, II, III and IV respectively (P 0.05). The results of our study suggest that iv lidocaine 0.5 mg.kg(-1) is the minimal dose required to suppress fentanyl-induced cough when administered one minute prior to fentanyl. Any further increase in the lidocaine dose does not reduce the incidence or severity of fentanyl-induced cough.