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Background: Preventing emergence cough after nasal surgery is critical. Emergence cough can provoke immediate postoperative bleeding, which leads to upper airway obstruction. In the present study, we compared the effect-site concentration (Ce) of remifentanil to prevent emergence cough after propofol anesthesia for nasal surgery when remifentanil was or was not combined with dexmedetomidine., Methods: Forty-seven patients with propofol-remifentanil anesthesia for nasal surgery were randomly assigned to a dexmedetomidine group (Group D, n = 23) or a saline group (Group S, n = 24). Group D and Group S were infused with dexmedetomidine (0.5 μg/kg) and saline, respectively, for 10 min before the completion of surgery. A predetermined Ce of remifentanil was infused until extubation. Remifentanil Ce to prevent cough in 50 and 95% of patients (EC 50 and EC 95 ) was estimated using modified Dixon's up-and-down method and isotonic regression. Hemodynamic and recovery parameters were recorded., Results: The EC 50 of remifentanil Ce was significantly lower in Group D than in Group S (2.15 ± 0.40 ng/mL vs. 2.66 ± 0.36 ng/mL, p = 0.023). The EC 95 (95% CI) of remifentanil Ce was also significantly lower in Group D [2.75 (2.67-2.78) ng/mL] than in Group S [3.16 (3.06-3.18) ng/mL]. Emergence and recovery variables did not differ between the two groups., Conclusion: The remifentanil EC 50 to prevent cough after propofol-remifentanil anesthesia was significantly lower (approximately 19%) when a combination of remifentanil and 0.5 μg/kg dexmedetomidine was used than when remifentanil infusion alone was used in patients undergoing nasal surgery. Therefore, the Ce of remifentanil may be adjusted to prevent emergence cough when used in combination with dexmedetomidine., Trial Registration: ClinicalTrials.gov ( NCT03622502 , August 9, 2018).

BACKGROUND Despite the high frequency of hypotension during spinal anesthesia with proper sedation, no previous report has compared the hemodynamic effects of dexmedetomidine and midazolam sedation during spinal anesthesia. We compared the effects of bispectral index (BIS)-guided intravenous sedation using midazolam or dexmedetomidine on hemodynamics and recovery profiles in patients who underwent spinal anesthesia. MATERIAL AND METHODS One hundred and sixteen adult patients were randomly assigned to receive either midazolam (midazolam group; n=58) or dexmedetomidine (dexmedetomidine group; n=58) during spinal anesthesia. Systolic, diastolic, and mean arterial pressures; heart rates; peripheral oxygen saturations; and bispectral index scores were recorded during surgery, and Ramsay sedation scores and postanesthesia care unit (PACU) stay were monitored. RESULTS Hypotension occurred more frequently in the midazolam group (P<0.001) and bradycardia occurred more frequently in the dexmedetomidine group (P<0.001). Mean Ramsay sedation score was significantly lower in the dexmedetomidine group after arrival in the PACU (P=0.025) and PACU stay was significantly longer in the dexmedetomidine group (P=0.003). CONCLUSIONS BIS-guided dexmedetomidine sedation can attenuate intraoperative hypotension, but induces more bradycardia, prolongs PACU stay, and delays recovery from sedation in patients during and after spinal anesthesia as compared with midazolam sedation., Competing Interests: The authors have no potential conflict of interest to declare.

The purpose of this study was to evaluate the effects of low-dose dexmedetomidine on hemodynamics and anesthetic requirements during propofol and remifentanil anesthesia for laparoscopic cholecystectomy. Thirty adult patients were randomly allocated to receive dexmedetomidine infusion of 0.3 μg/kg/h (dexmedetomidine group, n = 15) or comparable volumes of saline infusion (control group, n = 15). Target controlled infusion of propofol and remifentanil was used for anesthetic induction and maintenance, and adjusted in order to maintain a bispectral index of 40-55 and hemodynamic stability. We measured hemodynamics and recorded total and mean infused dosages of propofol and remifentanil. For anesthesia induction and maintenance, mean infused doses of propofol (121 ± 27 vs. 144 ± 29 μg/kg/min, P = 0.04) and remifentanil (118 ± 27 vs. 150 ± 36 ng/kg/min, P = 0.01) were lower in the dexmedetomidine group than in the control group, respectively. The dexmedetomidine group required 16 % less propofol and 23 % less remifentanil. During anesthetic induction and maintenance, the dexmedetomidine group required fewer total doses of propofol (9.6 ± 2.3 vs. 12.4 ± 3.3 mg/kg, P = 0.01) and remifentanil (9.6 ± 3.4 vs. 12.7 ± 2.6 μg/kg, P = 0.01). The change in mean arterial pressure over time differed between the groups (P < 0.05). Significantly lower mean arterial pressure was observed in the dexmedetomidine group than in the control group at immediately and 5 min after pneumoperitoneum. The time to extubation after completion of drug administration did not differ between the groups (P = 0.25). This study demonstrated that a low-dose dexmedetomidine infusion of 0.3 μg/kg/h reduced propofol and remifentanil requirements as well as hemodynamic change by pneumoperitoneum without delayed recovery during propofol-remifentanil anesthesia for laparoscopic cholecystectomy.

Background: The pharmacokinetics and pharmacodynamics of an anesthetic drug may be influenced by gender. The purpose of this study was to compare effect-site half maximal effective concentrations (EC50) of propofol in male and female patients during i-gel insertion with dexmedetomidine 0.5 μg/kg without muscle relaxants., Methods: Forty patients, aged 20-46 years of ASA physical status I or II, were allocated to one of two groups by gender (20 patients per group). After the infusion of dexmedetomidine 0.5 μg/kg over 2 min, anesthesia was induced with a pre-determined effect-site concentration of propofol by target controlled infusion. Effect-site EC50 values of propofol for successful i-gel insertion were determined using the modified Dixon's up-and-down method., Results: Mean effect-site EC50 ± SD of propofol for successful i-gel insertion was significantly higher for men than women (5.46 ± 0.26 μg/ml vs. 3.82 ± 0.34 μg/ml, p < 0.01). The EC50 of propofol in men was approximately 40% higher than in women. Using isotonic regression with a bootstrapping approach, the estimated EC50 (95% confidence interval) of propofol was also higher in men [5.32 (4.45-6.20) μg/ml vs. 3.75 (3.05-4.43) μg/ml]. The estimated EC95 (95% confidence interval) of propofol in men and women were 5.93 (4.72-6.88) μg/ml and 4.52 (3.02-5.70) μg/ml, respectively., Conclusions: During i-gel insertion with dexmedetomidine 0.5 μg/kg without muscle relaxant, male patients had higher effect-site EC50 for propofol using Schnider's model. Based on the results of this study, patient gender should be considered when determining the optimal dose of propofol during supraglottic airway insertion., Trial Registration: ClinicalTrials.gov identifier: NCT02268656. Registered August 26, 2014.