Background:Vitrectomy under general anesthesia is considered as a candidate for ambulatory surgery. An anesthetic method with high quality of postoperative recovery should be selected for successful ambulatory surgery. We thus compared quality of postoperative recovery on the day of vitrectomy using the Quality of Recovery (QoR)-40 questionnaire between propofol total intravenous anesthesia (propofol group) and desflurane inhalation anesthesia (desflurane group) as the 2 representative anesthetic methods.Methods:Eighty-four patients (20–80 years old) undergoing elective vitrectomy under general anesthesia were randomized into 2 groups. The propofol group received propofol and remifentanil using effect-site target-controlled infusion (TCI), and the desflurane group received desflurane inhalation and remifentanil using effect-site TCI. We assessed quality of recovery at 6 hours after surgery through interviews using the QoR-40 questionnaire. We also collected data related to recovery and complications during emergence and recovery period.Results:The median of QoR-40 score on the day of surgery was significantly higher in the propofol group than that in the desflurane group (181.0 vs 169.5, respectively; P = .033). In particular, propofol group had significantly higher scores for physical comfort and physical independence dimensions. The amount of remifentanil administered was significantly higher, and the emergence time was significantly longer in propofol group. However, there were no significant differences in other complications between the 2 groups.Conclusions:Propofol total intravenous anesthesia provided significantly better quality of recovery on the day of surgery than desflurane inhalation anesthesia.

Patients undergoing shoulder surgery in the beach chair position (BCP) under general anaesthesia may be at risk of cerebral desaturation. Increasing end-tidal carbon dioxide (EtCO 2 ) is the most convenient and powerful method for the management of cerebral desaturation. The purpose of this study was to investigate the quantitative relationship between EtCO 2 and cerebral oxygen saturation (rSO 2 ) and to identify the associated influencing factors. Fifty-one patients undergoing arthroscopic shoulder surgery in the BCP under general anaesthesia completed this study. Desflurane and remifentanil were used, and EtCO 2 was steadily increased and then decreased by adjusting the ventilator settings every 3 min. so that time lag of rSO 2 response to EtCO 2 changes could be delineated. Near-infrared spectroscopy was used to monitor rSO 2 response. An indirect response model was used to examine the relationship between EtCO 2 and rSO 2 . To determine the relevant covariates, a stepwise approach was used. There was a linear relationship between rSO 2 and EtCO 2 with a slight delay in the peak of rSO 2 relative to EtCO 2 . Increase in end-tidal desflurane concentration led to a slower response of rSO 2 to the changes of EtCO 2 (p = 0.0002). The presence of diabetes mellitus reduced the reactivity of rSO 2 to EtCO 2 changes (p < 0.0001). This model-based approach revealed that diabetes mellitus attenuates the response of rSO 2 to changes in EtCO 2 . The management of cerebral desaturation by hypercapnia in patients with diabetes may be less effective than in non-diabetic patients under general anaesthesia with BCP.The beach chair position (BCP) under general anaesthesia with induced hypotension is commonly used in arthroscopic shoulder surgery [1]. Unlike the BCP in an awake state in which the compensatory mechanism to increase blood pressure occurs, the BCP under general anaesthesia is associated with significant hypotension and cerebral desaturation [2][3][4]. Further hypotension induced for better visualization of the surgical field might aggravate cerebral desaturation [4,5]. As cerebral desaturation during surgery is associated with postoperative cognitive dysfunction and stroke [6,7], prevention and treatment of cerebral desaturation is necessary.As cerebral oxygenation is dependent on cerebral perfusion and oxygen transport, interventions for the prevention and treatment of cerebral desaturation during shoulder surgery include increasing systemic arterial pressure with vasopressors, increasing end-tidal carbon dioxide (EtCO 2 ) with ventilation adjustment and increasing fraction of inspired oxygen (FiO 2 ) [3,4,8,9]. Although increases in systemic arterial pressure may cause rapid increases in cerebral blood flow (CBF), CBF returns to its baseline value within a few seconds by the mechanism of cerebral autoregulation, which aims to maintain a stable CBF over a wide range of mean arterial pressures (MAP) of 70-150 mmHg [10][11][12]. Moreover, increases in arterial pressure may worsen visualization of the sur...

Sedation can increase patient comfort during spinal anaesthesia. Understanding the relationship between the propofol effect-site concentration (Ce) and patient sedation level could help clinicians achieve the desired sedation level with minimal side effects. We aimed to model the relationship between the propofol Ce and adequate and deep sedation and also incorporate covariates. Thirty patients scheduled for orthopaedic surgery received spinal anaesthesia with 0.5% bupivacaine. Propofol was administered via an effect-site target-controlled infusion device using the Schnider pharmacokinetic model. The pharmacodynamic models for both adequate sedation [Observer's Assessment of Alertness/Sedation (OAA/S) scores of 3-4] and deep sedation (OAA/S scores of 1-2) were developed using nonlinear mixed-effects modelling. Increments in the propofol Ce were associated with increased depths of sedation. In the basic model, the estimated population Ce 50 values for adequate and deep sedation were 0.94 and 1.52 lg/ml, respectively. The inclusion of the patient's age and sensory block level for adequate sedation and of age for deep sedation as covariates significantly improved the basic model by decreasing the objective function's minimum value from 10696.72 to 10677.92 (p = 0.0003). The simulated Ce 50 values for adequate sedation in 20-year-old patients with a T 12 sensory level and in 80-year-old patients with a T 4 level were 1.63 and 0.53 lg/ml, respectively. Both age and sensory block level should be considered for adequate sedation, and the propofol concentration should be reduced for elderly patients with a high spinal block to avoid unnecessarily deep levels of sedation.Propofol is one of the most commonly used drugs for sedation during spinal anaesthesia because of its rapid onset, easy titration and rapid offset. However, propofol frequently induces unnecessary deep sedation or side effects such as respiratory and cardiovascular depression because it has a narrow therapeutic range [1][2][3]. The use of a target-controlled infusion (TCI) system for propofol administration allows rapid induction and safe maintenance of the desired level of sedation, thereby making it ideal for technically demanding procedures [4][5][6]. Understanding the concentration-response relationship of sedation is fundamental for the safe use of propofol with incorporating factors influencing the sedative effect. However, few studies have evaluated the quantitative relationship between the effect-site concentration (Ce) of propofol and its sedative effect under spinal anaesthesia, although propofol is considered to induce sedation in a dose-dependent manner [7]. Therefore, we attempted to model the relationship between propofol Ce and sedation and also to characterize the covariates in the pharmacodynamic relationship between propofol Ce and adequate and deep sedation in patients undergoing spinal anaesthesia. Materials and MethodsStudy population. This study was approved by the ethics committee of the Yonsei University Health System (4...

PurposeSedatives must be carefully titrated for patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) as oversedation may lead to disastrous respiratory outcomes. This study aimed to investigate the relations between the effect-site concentration (Ce) of propofol and sedation and airway obstruction levels in patients with OSAHS.Materials and MethodsIn 25 patients with OSAHS, sedation was induced by 2% propofol using target-controlled infusion. Sedation and airway obstruction levels were assessed using the Observer's Assessment of Alertness/Sedation Scale and a four-category scale, respectively. The relationships between propofol Ce and sedation and airway obstruction were evaluated using a sigmoid Emax model. Pharmacodynamic modeling incorporating covariates was performed using the Nonlinear Mixed Effects Modeling VII software.ResultsIncreased propofol Ce correlated with the depth of sedation and the severity of airway obstruction. Predicted Ce50(m) (Ce associated with 50% probability of an effect≥m) for sedation scores (m≥2, 3, 4, and 5) and airway-obstruction scores (m≥2, 3, and 4) were 1.61, 1.78, 1.91, and 2.17 µg/mL and 1.53, 1.64, and 2.09 µg/mL, respectively. Including the apnea-hypopnea index (AHI) as a covariate in the analysis of Ce50(4) for airway obstruction significantly improved the performance of the basic model (p<0.05).ConclusionThe probability of each sedation and airway obstruction score was properly described using a sigmoid Emax model with a narrow therapeutic range of propofol Ce in OSAHS patients. Patients with high AHI values need close monitoring to ensure that airway patency is maintained during propofol sedation.