Remifentanil requirement for i-gel insertion is reduced in male patients with Parkinson’s disease undergoing deep brain stimulator implantation: an up-and-down sequential allocation trial

BACKGROUND: Laryngeal mask airways have been widely used in clinical practice. The aim of this study was to investigate whether the remifentanil requirement for facilitation of i-gel insertion in Parkinson’s disease (PD) patients undergoing deep brain stimulation (DBS) surgery was different from that in non-PD (NPD) patients undergoing intracranial surgery. STUDY DESIGN: An up-and-down sequential allocation trial. METHODS: Male patients aged between 40 and 64 years old were enrolled. The first patient in each group (PD and NPD) group received an effect-site concentration (Ce) of remifentanil (Minto pharmacokinetic model) of 4.0 ng.ml(−1) during a target-controlled infusion (TCI) of 3.5 μg.ml(−1) propofol (Marsh pharmacokinetic model). The next dose of remifentanil was determined by the response of the previous patient. The Ce of remifentanil required for i-gel insertion in 50% of patients (EC(50)) was estimated by the modified Dixon’s up-and-down method and by probit analysis. RESULTS: The PD group included 24 patients and the NPD group included 23. The EC(50) of remifentanil for i-gel insertion during a TCI of 3.5 μg.ml(−1) propofol estimated by the modified Dixon’s up-and-down method in PD patients (2.38 ± 0.65 ng.ml(−1)) was significantly lower than in NPD patients (3.21 ± 0.49 ng.ml(−1)) (P = 0.03). From the probit analysis, the EC(50) and EC(95) (effective Ce in 95% of patients) of remifentanil were 1.95 (95% CI 1.52–2.36) ng.ml(−1) and 3.12 (95% CI 2.53–5.84) ng.ml(−1) in PD patients and 2.85 (95% CI 2.26–3.41) ng.ml(−1) and 4.57 (95% CI 3.72–8.54) ng.ml(−1) in NPD patients, respectively. CONCLUSIONS: The remifentanil requirement for successful i-gel insertion is reduced in male PD patients undergoing DBS implantation during propofol TCI induction. Clinicians should closely monitor the remifentanil requirement in patients with PD. TRIAL REGISTRATION: Registered at http://www.chictr.org.cn (ChiCTR1900021760).