Randomized comparison of effects of two different remifentanil dose on surgical conditions during endoscopic sinus surgery

BACKGROUND: The combination of propofol and remifentanil results in better surgical field conditions during endoscopic sinus surgery than inhalation anesthesia. This study compared surgical field conditions between two groups receiving low or high concentration of remifentanil and hemodynamic variables using non-invasive cardiac monitoring. METHODS: Fifty-four patients between ASA I or II, were randomly assigned to either the high-concentration remifentanil group (HR), effect-site concentration of 8 ng/mL or the low-concentration remifentanil group(LR), effect-site concentration of 4 ng/mL. Surgical condition was evaluated using the Boezaart Surgical Field Grading Scale presented by Boezaart. Cardiac output was measured using non-invasive cardiac monitoring (CSN-1901). RESULTS: In terms of surgical conditions, the HR group showed significantly lower values than the LR group (p = 0.021) at 90 min after the start of surgery. Heart rate was significantly lower in the HR group than the LR group at 30, 60, and 90 min after the start of surgery (30 min; p = 0.005, 60 min; p = 0.002, 90 min; p = 0.001). There was a statistically significant decrease of cardiac output in the HR group compared to the LR group immediately after endotracheal intubation and at 30, 60, and 90 min after the start of surgery (Base; P = 0.222, Intubation; P = 0.016, 30 min; p = 0.014, 60 min; P = 0.012, 90 min; P = 0.008). However, in the case of stroke volume, there was no significant difference between the two groups in all measurements. CONCLUSION: When comparing the HR group and the LR group, the surgical condition was improved at 90 min after the start of surgery. MAP was lower in the HR group and this was a result of reduction in cardiac output primarily attributed to the decrease in heart rate rather than a decrease in stroke volume. TRIAL REGISTRATION: Clinical Trial Registry of the Republic of Korea (KCT0006453).