The incidence of cough induced by remifentanil during anesthetic induction was decreased by graded escalation of the remifentanil concentration

BACKGROUND It is well known that opioids induce coughing. Many drugs such as lidocaine and ketamine are used to effectively prevent the coughing induced by opioids and this has been revealed to be effective. In this study, we evaluated the preventive effect of a graded escalation of the remifentanil concentration using a target controlled infusion pump and we compared this with the effect of lidocaine. METHODS One hundred fifty ASA I and II patients who were scheduled for elective surgery were randomly divided into 3 groups. The patients were pretreated with 2% lidocaine 1 mg/kg (Group L) or saline (Group S) and remifentanil infusion (an effect site concentration of 4.0 ng/ml) was followed 1 minute later by using a target controlled infusion pump. Group R was pretreated with saline and this was followed by remifentanil infusion (effect site concentration of 2.0 ng/ml at first and then it was reset to 4.0 ng/ml). We evaluated the incidence, severity and onset time of cough after remifentanil infusion. RESULTS The incidence of coughing was significantly decreased in Group R (6 cases, 12%) and Group L (7 cases, 14%), as compared to that of Group S (17 cases, 34%) (P < 0.05), but there was no significant difference between Group R and Group L. The groups showed no significant difference in the severity and the onset time of coughing. CONCLUSIONS This study demonstrated that administering graded escalation of the remifentanil concentration suppresses remifentanil-induced coughing as effectively as lidocaine 1 mg/kg pretreatment.