Effects of different concentrations of remifentanil on the effective concentration 50%and anesthetic quality to propofol inhibiting gastroscopy

Abstract:

Objective: To investigate the effect of different concentrations of remifentanil on the effective concentration 50% (EC₅₀) and the anesthesia quality in patients receiving target controlled infusion (TCI) of propofol. Methods: One hundred and fifty patients who received endoscopic mucosal resection (EMR), with ASA physical statusⅠ/Ⅱand ages of (59.11±10.08) years old, were randomly divided into four groups: C group (propofol group), R1 group (0.5 ng/mL of remifentanil combined with propofol), R2 group (1.0 ng/mL of remifentanil combined with propofol) and R3 group (1.5 ng/mL of remifentanil combined with propofol). The Dixon’s sequential method was used to determine the EC₅₀of propofol concentration, with initial plasma effect-side concentration of 5.0 μg/mL via TCI and step size of 1 μg/mL. Concentration of propofol was able to be increased for next one patient when deglutition reflex or body movement in gastroscope placement for one patient, whereas the concentration was going to be decreased. The EC₅₀ and 95%confidence interval (CI) of propofol in different groups calculated by Probit regression analysis. Adverse events of operative time, anesthesia and resuscitation time, intraoperative coughing and respiratory and heart rate depression were recorded. Results: EC₅₀of propofol in C group, R1 group, R2 group and R3 group were 6.686 μg/mL, 6.476 μg/mL, 5.970 μg/mL and 5.640 μg/mL, respectively. The operation and anesthesia duration among four groups had no statistically significant differences (P>0.05). For the resuscitation time, there was no statistically significant difference between C group and R1 group (P>0.05), but there were statistically significant differences between R2 group and R3 group and C group (P<0.05). For heart rate (HR) during placing gastroscope, there was no statistically significant difference between C group and R1 group (P>0.05), but there were statistically significant differences between R2 group and R3 group and C group (P<0.05). For mean arterial pressure (MAP), there was no statistically significant difference between C group and R1 group (P>0.05), but there were statistically significant differences between R2 group and R3 group and C group (P<0.05). For respiratory depression during anesthesia, there was no statistically significant difference between C group and R1 group (P>0.05), but there were statistically significant differences between R2 group and R3 group and C group (P<0.05). Conclusion: In endoscopic mucosal resection, remifentanil concentration of 1.0 ng/mL combined with the propofol TCI is safer and more effective, without less coughing, respiratory depression or bradycardia.