Background: Preinduction i.v. fentanyl bolus is associated with coughing in 28-65% of patients. Fentanyl-induced coughing (FIC) is not always benign and can be remarkably troublesome at the most critical moment of induction of anaesthesia when airway reflex is lost. We postulated that the huffing manoeuvre, a forced expiration against open glottis, just before i.v. fentanyl, may suppress this undesirable spasmodic cough.
Methods: Three hundred patients of ASA I and II, aged 18-60 yr, undergoing elective surgical procedures were randomly allocated into two groups consisting of 150 patients. Both groups received i.v. fentanyl (2.5 microg kg(-1)). Group 1 patients breathed normally whereas Group 2 patients were asked to perform huffing manoeuvre just before the fentanyl injection. The incidence of cough was recorded for 1 min before the induction of anaesthesia, and graded as mild (1-2 cough), moderate (3-5 cough), and severe (>5 cough). The incidence of FIC was analysed with Fisher's exact test and severity was analysed with the Mann-Whitney U-test. A P-value of <0.05 was considered significant.
Results: The incidence of cough was 32% in the control group and 4% in the huffing manoeuvre group (P<0.00). In the control group, 12% of FIC cases were moderate to severe in nature whereas no patient suffered severe coughing in the huffing manoeuvre group (P=0.049).
Conclusions: A huffing manoeuvre performed just before i.v. fentanyl (2.5 microg kg(-1)) significantly reduces the incidence and severity of FIC in the majority of the patients.