Propofol Bolus Fails to Decrease Cough

The administration of propofol as a bolus fails to decrease cough after use of desflurane in general anaesthesia, according to a study presented here at the 2018 Annual Meeting of the Canadian Anesthesiologists Society (CAS).

Cough is not just bothersome, but it can interfere with clinical outcomes, making the prevention of cough clinically significant in anaesthesia practice, said Marie-Felix Ouellet, MD, University of Montreal, Montreal, Ontario, on June 17. “If a patient was undergoing surgery like a thyroidectomy, you would not want the patient to cough,” explained Dr. Ouellet.

Extubation becomes more of a challenge when cough is present, so avoiding the cough is vital to ensure extubation is done without complications. Moreover, patients are more likely to develop throat pain after surgery if they are experiencing cough.

Because propofol inhibits reflexes of the airway, the investigators sought to determine whether administration of propofol would decrease cough incidence and severity (a 50% decrease in cough incidence was considered clinically significant).

The researchers enrolled 154 patients who were categorised as I through III according to the American Society of Anesthesiologists and who underwent general anaesthesia and were permitted to use opioids, such as remifentanil, fentanyl, and sufentanil. Patients received a bolus of propofol 0.5 mg/kg or saline at the end of surgery. The anaesthetic (desflurane) was not continued, and fresh oxygen flow was increased to 10 L/min. Assessment of the incidence and severity of cough during emergence of anaesthesia and until 5 minutes after extubation was performed by an individual blinded to the intervention. Time to extubation, postoperative nausea and vomiting, and respiratory complications were also noted.

The study was sufficiently powered to show a difference between the 2 groups in regard to cough. The researchers controlled for factors such as body mass index, cigarette smoking, and the use of angiotensin-converting enzyme inhibitors. In addition, they did not administer an agent such as lidocaine, because it could prevent cough and interfere with assessing the impact of propofol.

Treatment with propofol did not significantly decrease the incidence of cough (95.9% vs 83.8% with saline; P = .064). Cough intensity was also not influenced by the bolus. Time to extubation, however, was extended by 3 min 26 s for patients exposed to the propofol bolus, which was statistically significant (P < .01). The patients exposed to propofol also required more vasopressors at emergence (P = .035). A statistically significant difference was observed in sore throat among patients who received propofol (P = .034).

Dr. Ouellet speculated that given propofol’s short half-life, the administration as a bolus may explain why investigators saw no difference in impact on cough. Administration of propofol as an infusion may have produced a different result and reduced cough incidence and severity.
[Presentation title: Efficacy of a Propofol Bolus Against Placebo to Prevent Cough at Emergence of General Anesthesia With Desflurane. Abstract 441311]