Comparison of lidocaine, huffing maneuver and combination of both in prevention fentanyl induced cough before induction of anesthesia: a double-blind, prospective, randomized placebo-controlled study.

Background Intravenous bolus injection of fentanyl has been frequently reported to be associated with cough reflex during patient anesthesia. However, the search for the most effective protocol continues. This study aimed to compare the effect of reducing cough reflex after injection of fentanyl in a fusion protocol by combining the injections of lidocaine and Huffing maneuver and comparing with a placebo control group, before anesthesia induction. Methods This prospective randomized controlled trial study was performed on 400 patients who were divided into four groups of combined protocol (group 1), lidocaine group (group 2), Huffing maneuver group (group 3), and the control receiving normal saline (group 4). Then patients were injected with 2. 5 μg /kg fentanyl and monitored for 2 min regarding their cough reflex, as well as the severity. Results In group one, 9 patients (9%), in group two, 45 patients (45%), 22 patients (22%) in group three, and in group four, 75 patients (75%), developed cough reflex following fentanyl injection. Also, 13 patients (13%) developed moderate and 4 (4%) developed severe coughs in the control group reported, while no reports of severe or moderate cough were among the intervention groups. There was a significant difference between the intervention group and the control group both in terms of the rate and severity of the fentanyl-induced cough. Conclusion By using a combination of lidocaine injection along and Huffing maneuver, better results can be obtained in reducing the frequency, and also the severity of cough followed by fentanyl injection. Trial registration The trial was registered with IRCT.IR (09/03/2018-No. IRCT20141009019470N74 ).