ABSTRACT
BACKGROUND: The aim of the study was to investigate whether the incidence of cough after intravenous fentanyl depends on the speed of injection. METHODS: With ethics committee approval, 476 ASA class I-III nonsmoking patients free of bronchial hyperreactivity and respiratory tract infection undergoing general anaesthesia for elective surgery were randomized to either 1.5 microg/kg fentanyl injected over 2, 5 or 10 s or placebo (saline) via a peripheral intravenous cannula. The primary endpoint was the incidence of cough within 5 min after completion of injection. RESULTS: The study was terminated for futility after enrollment of 476 patients because an interim analysis yielded an incidence of cough of 3%, 3% and 6% in the three fentanyl groups, respectively, and of 2% in the placebo group, with no difference between groups (P=0.374, chi(2) test for cough between fentanyl and placebo groups). CONCLUSIONS: Under the conditions of our study, the incidence of cough after 1.5 microg/kg fentanyl injected intravenously over 2, 5 or 10 s was between 3% and 6%, unrelated to the speed of injection and not different from placebo.
