BackgroundRemifentanil infusion during emergence lowers cough. Effect-site concentration (Ce) of remifentanil using target-controlled infusion (TCI) has been evaluated in previous studies. Recent studies revealed the existence of sex-related differences in remifentanil Ce in young and elderly patients. Thus, there was the need to re-evaluate the effect of age in single sex. We investigated the remifentanil Ce for suppressing emergence cough in young and elderly male patients and evaluated the age-related differences.Patients and methodsIn total, 25 young (ages between 20 and 50 years) and 24 elderly (ages between 65 and 75 years) male patients undergoing laparoscopic cholecystectomy were enrolled. Anesthesia was implemented with remifentanil using TCI and sevoflurane. The remifentanil Ce for suppressing emergence cough was estimated for each group using Dixon’s up-and-down method and isotonic regression method with a bootstrapping approach.ResultsThe remifentanil Ce for suppressing emergence cough in 50% (EC50) and 95% (EC95) of the patients was comparable between the young and elderly patients. Isotonic regression demonstrated that the EC50 (83% confidence interval [CI]) of remifentanil was 2.56 (2.39−2.75) ng/mL in the young patients and 2.15 (1.92−2.5) ng/mL in the elderly patients. The EC95 (95% CI) of remifentanil was 3.33 (2.94−3.46) ng/mL in the young patients and 3.41 (3.18−3.48) ng/mL in the elderly patients. Dixon’s up-and-down method also demonstrated that the EC50 was comparable between the two groups (2.69±0.32 ng/mL vs 2.39±0.38 ng/mL, P=0.132).ConclusionThe remifentanil Ce for suppressing emergence cough following extubation during general anesthesia was comparable between young and elderly male patients. It indicates that age-related differences in remifentanil requirement for suppressing emergence cough did not exist in male sex.

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Older adults exhibit reduced physiological responses to beta-adrenergic stimulation and parasympathetic inhibition. This study aimed to investigate the effect of reducing the incidence of bradycardia in the atropine and ephedrine pretreatment group compared to the control group in older adults who received spinal anesthesia with intravenous dexmedetomidine. Overall, 102 older adults aged over 65 years were randomly divided into three groups, and saline (control group), atropine at 0.5 mg (atropine group), and ephedrine at 8 mg (ephedrine group) were administered intravenously to each group as pretreatment. Immediately after spinal anesthesia, dexmedetomidine loading and study drug injections were commenced. The primary outcome was the incidence of bradycardia (<50 beats per min) within 60 min following dexmedetomidine loading. The incidence of bradycardia requiring atropine treatment was significantly higher in the control group than in the atropine and ephedrine groups (27.3% vs. 6.1% and 8.8%, respectively; p = 0.035), and no difference was noted between the atropine and ephedrine groups. Therefore, if ephedrine or atropine is selected and used according to the patient’s condition and clinical situation, it may be helpful in preventing bradycardia during spinal anesthesia using dexmedetomidine in older patients.

The management of patients with history or suspicion of difficult intubation can be challenging, especially in surgical procedures requiring one-lung ventilation. The ease of insertion of silicone double lumen tube (DLT) have previously been shown to be comparable to polyvinyl single lumen tube (SLT) in fiberoptic bronchoscope (FOB) tracheal intubation. Hence, in difficult airway situation, we hypothesized that the performance of insertion of silicone DLT would also be non-inferior to polyvinyl SLT in FOB intubation. We used a neck collar to mimic patients with difficult airway. 80 patients who required one-lung ventilation were enrolled in a prospective, randomized, non-inferiority trial. Patients were randomly allocated to the DLT or SLT groups (SLT with bronchial blocker). Neck collar was supplied to all patients before FOB intubation. The time of insertion for FOB, railroading, tracheal intubation, and total procedure were measured. The difficulty of railroading was evaluated in 4 grades. In the DLT group, the railroading was significantly shorter and easier comparing to the SLT group. The total procedure was also simpler and faster in the DLT group. While simulated difficult airways may not fully replicate actual difficult airways, we suggest that fiberoptic intubation with silicone DLT could be a feasible first-line option for patients with expected difficult airways requiring lung separation, unless the size of the DLT relative to the patient’s airway is problematic.Trial registration: NCT03392766.