In regard to our low incidence of postoperative nausea and vomiting (PONV) after bimaxillary osteotomies, minimizing the use of inhalational agents and narcotic pain medication are the two main focuses in our clinical practice, as inhalational agents and narcotics are associated with an increased incidence of PONV.
For orthognathic surgery performed at our institution, we have a standard protocol for the prevention of PONV, which we mentioned in the discussion section of our article : “First, a pre-emptive pain management protocol…”, “Second, the effective use of long-acting local anaesthetics … for maxillary and mandibular nerve blocks and local infiltrations…”, “Third, postoperative pain was managed with cyclooxygenase 2 (COX-2) inhibitors and non-steroidal anti-inflammatory drugs (NSAIDS) instead of opioids. Finally, patients were also given anti-emetic prophylaxis with dexamethasone at induction and ondansetron at the end of the operation”. The long-acting maxillary and mandibular nerve blocks given intraoperatively are effective in blocking most of the physiological responses triggered by surgical stimuli. This in turn reduces the use of narcotics and inhalational agents intraoperatively and the requirement for postoperative pain control when patients recover in the post anaesthesia care unit (PACU). The use of narcotics such as methadone during induction, remifentanil during surgery, and fentanyl or oxycodone in the PACU may contribute to the higher incidence of PONV mentioned in this letter.
Regarding the emergence time from general anaesthesia to extubation in our study, we titrate the concentration of our anaesthetics according to the amount of surgical stimulation experienced by the patients and their vital signs. Typically, we turn off the inhalational agent, sevoflurane, when the surgeon is closing the incision for the second sagittal split osteotomy site. Based on our experience, the vast majority of our patients are able to follow verbal commands at the completion of the procedure. The amount of time between completion of the procedure and extubation is usually less than 20 min after bimaxillary osteotomies.
Regarding the readers’ comments on the use of remifentanil and desflurane, remifentanil is not on the drug formulary at our institution; we simply do not have access to remifentanil.
Due to the tachycardic side effect of desflurane, our anaesthesiologists prefer the use of sevoflurane during the maintenance phase of anaesthesia. We agree with the readers’ comment that the combined use of desflurane and remifentanil is a good option to provide quick emergence from general anaesthesia.