Abstract:Objective To determine the median effective effect-site concentration (EC50) of remifentanil required to inhibit hemodynamic responses induced by intubation during target-controlled infusion (TCI) of propofol in patients with Parkinson’s disease. Methods A 11 matched case control design was used in the study. Thirty-one ASAⅠ-Ⅱ patients with Parkinson’s disease undergoing general anesthesia were enrolled, and 31 controls were the hospitalized patients with non-Parkinson’s disease during the same period (same sex, age ±3 years old). A TCI of propofol was used to maintain a predetermined effect-site concentration of 3 μg/mL. The target effect-site concentration of remifentanil was determined by a modified Dixon’s up-and-down sequential method. The initial target effect-site concentrations of remifentanil were 3 ng/mL in the two groups and the increments or decrements between the two consecutive patients were 0.2 ng/mL. A positive response meant that either the heart rate or the systolic blood pressure was elevated by 15% in the first 5 min after intubation. Results There was no patient showed sign of muscle rigidity, and no patient recalled awareness during anesthesia in postoperative follow-up. During TCI of propofol, the EC50 of remifentanil required for inhibiting intubation induced hemodynamic responses for patients with Parkinson’s disease was 2.20 ng/mL (95% confidence interval: 1.86-2.60 ng/mL). And the EC50 of remifentanil required for control group was significantly higher than for patients with Parkinson’s disease (2.93 ng/mL, 95% confidence interval: 2.72-3.15 ng/mL). Conclusion When combined with TCI of propofol (target effect-site concentration 3 μg/mL), the EC50 of remifentanil required for inhibiting intubation induced hemodynamic responses for patients with Parkinson’s disease is less than that for non-Parkinson’s disease.