Effect of equivalent doses of fentanyl, sufentanil, and remifentanil on the incidence and severity of cough in patients undergoing abdominal surgery: A prospective, randomized, double-blind study

Background: Fentanyl congeners have been found to induce cough during induction of general anesthesia. Studies of fentanyl and sufentanil have found incidence rates of 28% to 65% and 15%, respectively. However, no study has assessed the occurrence of cough induced by remifentanil.Objective: The aim of this study was to assess the effect of equivalent doses of fentanyl, sufentanil, and remifentanil on cough.Methods: Patients rated American Society of Anesthesiologists class I or II of either sex, aged 18 to 60 years, who were scheduled for elective abdominal surgery with general anesthesia were randomly and equally assigned to 3 groups using a computer-generated table of random numbers. The patients received equivalent doses of fentanyl 2 μg/kg, sufentanil 0.2 μg/kg, or remifentanil 2 μg/kg via IV push. Vital signs (systolic blood pressure SBP], heart rate HR], and oxygen saturation via pulse oximetry SpO₂]) and the occurrence and severity of cough were recorded for 2 minutes after drug administration by an anesthesiologist who was blinded to the drug treatment. The severity of cough was graded as none (0), mild (1–2), moderate (3–5), or severe (>5).Results: A total of 315 Chinese patients (197 women, 118 men; mean SD] age, 37.9 10.4] years) were approached for enrollment and assigned to 3 groups of 105 patients each; all patients completed the study protocol. The 3 treatment groups were similar in terms of demographic characteristics and type of abdominal surgery. The incidence of cough was significantly greater in the remifentanil group (57 54.3%] patients) than in the fentanyl group (35 33.3%]; P < 0.01) or the sufentanil group (32 30.5%]; P < 0.01). The severity of cough was significantly greater in the remifentanil group (severe, moderate, mild, none: 24, 7, 26, 48) than in the fentanyl (7, 9, 19, 70; P < 0.01) or sufentanil group (4, 2, 26, 73; P < 0.01). In all 3 groups, when the patients coughed, significant increases were observed in their SBP (128 12]–139 16] mm Hg; P < 0.01) and HR (74 10]–87 16] beats/min; P < 0.01). Within 2 minutes after drug administration, 62 patients (59%) in the remifentanil group experienced hypoxemia (SpO₂ <90%) necessitating manually assisted mask ventilation, while no patients experienced hypoxemia in the fentanyl or sufentanil group. Three patients (2.9%) in the remifentanil group experienced muscle rigidity and deterioration of SBP, HR, and SpO₂. No other adverse events were recorded.Cunclusion: Remifentanil was associated with a significantly greater incidence and severity of cough than equivalent doses of fentanyl or sufentanil. Fentanyl and sufentanil appeared comparable in these Chinese patients undergoing abdominal surgery.