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 ).