Effect of sex differences in remifentanil requirements for inhibiting the response to a CO2 pneumoperitoneum during propofol anesthesia: an up-and-down sequential allocation trial

EC50 and EC95 of Remifentanil for Inhibiting Bronchoscopy Responses in Elderly Patients During Fiberoptic Bronchoscopy Under Ciprofol Sedation: An Up-and-Down Sequential Allocation Trial

Background

Opioids are used to suppress cough during fiberoptic bronchoscopy (FOB). However, evidence regarding the optimal dose of remifentanil during FOB under ciprofol sedation is limited. This study aimed to investigate the effective concentration (EC) of remifentanil required to suppress bronchoscopy responses during FOB under ciprofol sedation in elderly patients.

Materials and Methods

Elderly patients aged 60 to 90 years with American Society of Anesthesiologists (ASA) physical status I-III, scheduled for FOB, were enrolled. Patients were assigned to either the male or the female group. Remifentanil was administered intravenously prior to ciprofol administration. The endpoints included responses to FOB, such as vocal cords movement, coughing, and body movement. The EC50 and EC95 values of remifentanil required to alleviate the responses to FOB were calculated using Dixon's up-and-down method for both male and female groups. Probit analysis was used to generate a dose-response curve.

Results

Thirty-nine patients (19 males and 20 females) were enrolled. The EC50 values (plasma concentration) of remifentanil for blunting FOB responses under ciprofol sedation were 3.25 (2.75 to 3.26) ng/mL and 2.25 (1.75 to 2.25) ng/mL in males and females, respectively (p = 0.0023). Probit analysis indicated that the EC50 of remifentanil required to suppress responses to FOB under ciprofol sedation was 3.102 [95% confidence interval (CI):2.694 to 3.749] ng/mL and 2.052 [95% CI: 1.345 to 2.750] ng/mL in males and females, respectively. The EC95 of remifentanil required to suppress responses to FOB under ciprofol sedation was 3.741 [95% CI: 3.366 to 7.699] ng/mL and 2.943 [95% CI: 2.456 to 9.533] ng/mL in males and females, respectively.

Conclusion

The results indicate differences between males and females in the EC50 and EC95 of remifentanil needed to suppress responses to FOB under ciprofol sedation while preserving spontaneous breathing in elderly patients.

Trial Registration

The study was registered with chictr.org.cn (ChiCTR2300077720; 17 th November 2023).

The influence of sex on the dosage of remimazolam co-administered with remifentanil for loss of consciousness in adult patients: an up-and-down sequential allocation trial

BACKGROUND

This study aimed to determine the 50% effective dose of remimazolam co-administered with remifentanil for loss of consciousness in men and women as well as to investigate whether there are between-sex differences.

METHODS

Using a modified Dixon's up-and-down allocation approach, we sequentially enrolled male and female patients aged 19-60 years with American Society of Anesthesiologists class I or II who were scheduled for robotic surgery. For both sexes, the starting remimazolam dose was 0.15 mg/kg, with a step size of 0.05 mg/kg. After achievement of a target effect-site concentration 2.0 ng/ml of remifentanil, and administration of a bolus dose of remimazolam, we assessed whether adequate loss of consciousness (defined as a Modified Observer's Assessment of Alertness/Sedation scale score < 2 within 2 min) was achieved.

RESULTS

We included 22 male and 22 female patients. Based on Dixon's up-and-down method, the 50% effective dose of remimazolam (mean ± standard error) was 0.13 ± 0.01 mg/kg and 0.17 ± 0.01 mg/kg in the male and female groups, respectively (P = 0.34). Isotonic regression analysis revealed that the 95% effective dose (95% confidence interval) was 0.19 (0.18-0.20) mg/kg in the male group and 0.29 (0.29-0.30) mg/kg in the female group.

CONCLUSIONS

There was no between-sex difference in the 50% effective dose of remimazolam for loss of consciousness; however, the 95% effective dose was significantly higher in female patients than in male patients.

TRIAL REGISTRATION

This study protocol was registered at Clinical Research Information Service (CRIS No. KCT0007951, 02/12/2022).

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 (EC₅₀) 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 EC₅₀ 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 EC₅₀ and EC₉₅ (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).

Type of anesthesia and quality of recovery in male patients undergoing lumbar surgery: a randomized trial comparing propofol-remifentanil total i.v. anesthesia with sevoflurane anesthesia

Background

Previous studies have shown that women achieve a better quality of postoperative recovery from total intravenous anesthesia (TIVA) than from inhalation anesthesia, but the effect of anesthesia type on recovery in male patients is unclear. This study therefore compared patient recovery between males undergoing lumbar surgery who received TIVA and those who received sevoflurane anesthesia.

Methods

Eighty male patients undergoing elective one- or two-level primary transforaminal lumbar interbody fusion (TLIF) were randomly divided into two groups: the TIVA group (maintenance was achieved with propofol and remifentanil) or sevoflurane group (SEVO group: maintenance was achieved with sevoflurane and remifentanil). The quality of recovery-40 questionnaire (QoR-40) was administered before surgery and on postoperative days 1 and 2 (POD1 and POD2). Pain scores, postoperative nausea and vomiting, postoperative hospital stay, anesthesia consumption, and adverse effects were recorded.

Results

The QoR-40 scores were similar on the three points (Preoperative, POD1 and POD2). Pain scores were significantly lower in the SEVO group than in the TIVA group on POD1 (30.6 vs 31.4; P = 0.01) and POD2 (32 vs 33; P = 0.002). There was no significant difference in the postoperative hospital stay or complications in the postanesthesia care unit between the TIVA group and the SEVO group.

Conclusions

This study demonstrates that the quality of recovery is not significantly different between male TLIF surgery patients who receive TIVA and those who receive sevoflurane anesthesia. Patients in the TIVA group had better postoperative analgesic effect on POD2.

Trial registration

This was registered at http://www.chictr.org.cn (registration number ChiCTR-IOR-16007987, registration date: 24/02/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01519-y.

Minimum Alveolar Concentration-Awake of Sevoflurane is Decreased in Patients with Parkinson's Disease: An Up-and-Down Sequential Allocation Trial

Background

An increasing number of patients with Parkinson’s disease (PD) will have surgery under general anesthesia. A previous study demonstrated that propofol requirement for inducing unconsciousness in PD patients was lower than that in non-PD (NPD) patients. However, the requirement of inhaled anesthetics in PD patients has not been clarified. The aim of this study was to investigate the minimum alveolar concentration-awake (MAC_awake) of sevoflurane in patients with PD compared to NPD patients.

Patients and Methods

The current study is an up-and-down sequential allocation trial. The initial end-tidal concentration of sevoflurane (CETsevo) was estimated by the response of the previous patient to verbal command using the Dixon’s up-and-down method. The first patient in each group received CETsevo at 1%, and the step size between patients was 0.2%.

Results

Forty-one patients including 20 PD patients and 21 NPD patients were enrolled. Patients’ characteristics and arterial blood gas parameters (except blood sodium) were comparable between two groups. The MAC_awake of sevoflurane estimated by the Dixon’s up-and-down method in PD patients (0.47% ± 0.08% [Mean ± S.D.]) was significantly lower than that in NDP patients (0.64% ± 0.10%) (P=0.003). The estimated difference in means was 0.17% (95% CI, 0.10–0.24%). Probit analysis showed that the MAC_awake of sevoflurane in PD and NPD patients was 0.49% (95% CI, 0.42–0.57%) and 0.67% (95% CI, 0.59–0.76%), respectively. The relative median potency was 0.73 (95% CI, 0.38–0.94).

Conclusion

Patients with PD exhibit a significantly lower MAC_awake of sevoflurane compared with NPD patients. Clinicians should avoid an overdose of sevoflurane in patients with PD.

Trial Registration

Registered at ChiCTR1900026956.