Background: An intervention to potentiate hypoxic pulmonary vasoconstriction may reduce intrapulmonary shunt and hypoxemia during one-lung ventilation. Previous animal studies reported that repeated intermittent hypoxic stimuli potentiated hypoxic pulmonary vasoconstriction, but no clinical study has examined the effects of this intervention on hypoxemia during one-lung ventilation. We thus performed a single-center, parallel-group, double-blind, randomized controlled trial to investigate whether repeated intermittent hypoxic stimuli to the operative lung reduce hypoxemia during the subsequent one-lung ventilation for thoracoscopic surgery. Methods: Patients undergoing one-lung ventilation were randomized into two groups (n = 68 each). Before one-lung ventilation, in the intermittent hypoxia group, the nondependent lung was not ventilated for 2 min and then ventilated for 2 min while the dependent lung was continuously ventilated. This was repeated five times. In the continuous normoxia group, both lungs were ventilated for 20 min. We measured SpO₂, PaO₂, FiO₂, PaCO₂, SaO₂, and central venous oxygen saturation during one-lung ventilation. The primary outcome was the number of patients with hypoxemia defined as a SpO₂ <95% during one-lung ventilation, which was analyzed with a chi-squared test. Results: Hypoxemia was less frequent in the intermittent hypoxia group than in the continuous normoxia group during OLV [6/68 (8.8%) vs 17/68 (25.0%), risk ratio (95% CI) 0.35 (0.15–0.84), p = 0.012]. The PaO₂ (p = 0.008 for 30 min and 0.007 for 60 min) and PaO₂/FiO₂ (p = 0.008 for both) were higher 30 and 60 min after starting one-lung ventilation, and the alveolar-arterial pressure gradient (p = 0.010) and shunt index (p = 0.008) were lower 30 min after starting one-lung ventilation in the intermittent hypoxia group than in the continuous normoxia group. Postoperative adverse events did not differ significantly between groups. Conclusions: Repeated intermittent hypoxic stimuli to the operative lung seemed to potentiate hypoxic pulmonary vasoconstriction, and thus reduced hypoxemia during the subsequent one-lung ventilation.

Since the patient’s airway is shared between an anesthesiologist and a surgeon, airway management during upper airway surgery can be challenging. Beyond the conventional method of general anesthesia, high-flow nasal oxygenation (HFNO) has recently been used as a key technique for tubeless anesthesia. HFNO provides humidified, heated oxygen up to 70 L/min, which promises improved oxygenation and ventilation, allowing for prolonged apneic oxygenation. In previous physiological and clinical studies, HFNO has been demonstrated that tubeless anesthesia safely provide an uninterrupted surgical field during laryngeal surgeries. Although tubeless anesthesia remains uncommon, it can be a good alternative to conventional anesthesia if an anesthesiologist and a surgeon select appropriate patients together with sufficient experience. A safe strategy for tubeless anesthesia, along with appropriate backup plans, including endotracheal intubation and high-frequency jet ventilation, should be considered for upper airway surgery.

Background: Opioids remain widely used for postoperative pain control after total knee arthroplasty (TKA); however, concerns about adverse effects and dependency drive interest in opioid-sparing alternatives. This study evaluated the efficacy and safety of opioid-sparing patient-controlled analgesia (PCA) after TKA.Methods: In this prospective, randomized, double-blind, non-inferiority study, 98 patients undergoing TKA under spinal anesthesia received either opioid-based PCA (continuous infusion of 1200 μg fentanyl, n = 49) or opioid-sparing PCA (continuous infusion of 150 mg ketorolac tromethamine and 100 mg nefopam hydrochloride, n = 49). Both groups received patient-controlled boluses of 300 μg fentanyl. The primary endpoint was the visual analog scale (VAS) pain score at rest on postoperative day (POD) 1, assessed using a 1.5-point non-inferiority margin. Secondary endpoints included additional analgesics, mobility, postoperative pain at rest and during ambulation, and adverse effects on PODs 1 and 2.Results: The mean VAS score at rest on POD 1 was 5.45 ± 2.48 in the opioid-based PCA group and 5.90 ± 2.31 in the opioid-sparing PCA group. The mean difference was 0.45 points (95% CI, −0.36 to 1.25), within the prespecified non-inferiority margin. Pain scores at each time point were non-inferior in the opioid-sparing group, whereas rescue analgesic requirements were significantly reduced on POD 2 (P = 0.006). Nausea and vomiting on POD 1 were more frequent with opioid-based group (34.7% vs. 12.2%, P = 0.009).Conclusions: Opioid-sparing PCA with ketorolac and nefopam provides non-inferior analgesia to opioid-based PCA, while reducing opioid consumption and drug-related adverse effects after TKA.

General anesthesia providing one-lung ventilation (OLV) with double-lumen endotracheal intubation has been considered inevitable for thoracic surgery. However, with the recent trend of less invasive surgical technique and enhanced recovery after surgery, tubeless anesthesia has been performed in various thoracic surgeries. The aim of this study was to establish a feasible and safe strategy of ventilator-assisted tubeless anesthesia in video-assisted thoracoscopic surgeries (VATS) based on single-institution experiences. We retrospectively reviewed the medical records of patients who underwent tubeless VATS from November 2019 to December 2021. Perioperative anesthetic and surgical variables as well as complications were reported. Seventeen patients with a median age of 29 and American Society of Anesthesiologists physical status I to II underwent video-assisted pulmonary wedge resection under monitored anesthesia care (MAC) using propofol and remifentanil. Mechanical ventilation was applied in synchronized intermittent mandatory ventilation with pressure support mode through facemask if respiratory support was required. During the operation, none of the patients showed hypoxemia or involuntary movement interfering operation. No patients were converted to general anesthesia or open thoracotomy unintentionally. All patients were discharged on median 2 days postoperatively without complications. Ventilator-assisted tubeless VATS is a feasible and safe option in low-risk patients undergoing video-assisted pulmonary wedge resection.

Background/Objectives: Accurate knowledge of tracheobronchial anatomy is essential for safe airway management, particularly during one-lung ventilation using double-lumen tubes (DLTs). However, population-specific morphometric data in Asian adults remain limited. We aimed to establish a comprehensive morphometric profile of the tracheobronchial tree in Korean adults using 2D and 3D computed tomography (CT), and evaluate the clinical implications for DLT sizing and right upper lobe (RUL) alignment. Methods: This retrospective observational study included 398 adults who underwent preoperative chest CT. Measurements included tracheal dimensions, bronchial lengths, bronchial diameters, and anteroposterior angle of the RUL orifice. Height tertiles and sex-stratified linear regression analyses were performed to evaluate height–bronchial diameter relationships. Results: Bronchial dimensions were larger in men; however, height was more closely related to bronchial diameter in women. In women, each 1 cm increase in height corresponded to a 0.071 mm increase in left and a 0.077 mm increase in right bronchial transverse diameter (p < 0.001 for both). The RUL orifice showed posterior deviation of 15.5 ± 12.2° in men and 9.9 ± 11.4° in women, with height and weight being independent but weak predictors (R² = 0.05). Bronchial diameter measurements showed consistent differences between 2D and 3D CT, with 2D images generally overestimating transverse diameters. Conclusions: The present analysis provides population-specific reference values for Korean adults. Our findings support the use of 2D CT as a practical tool for estimating bronchial dimensions and guiding DLT selection, and may serve as foundation for future airway devices tailored to Asian populations.

Background/Objectives: To evaluate whether gabapentin pretreatment modulates neuronal excitability and attenuates second-eye hyperalgesia in patients undergoing sequential bilateral cataract surgery under monitored anesthesia care with retrobulbar block. Methods: We conducted a prospective, parallel-group, randomized controlled trial with blinded outcome assessors at a tertiary university hospital. Patients aged > 60 years undergoing elective sequential bilateral cataract surgeries with a 1-week interval were enrolled. Participants were randomized 1:1 to receive gabapentin (100 mg three times daily for 1 week between surgeries) or no pretreatment. The primary outcome was the incidence of hyperalgesia, defined as greater intraoperative pain during the second-eye surgery compared to the first. Secondary outcomes included preoperative anxiety level, intraoperative and postoperative pain score, opioid rescue requirements, and surgeon/patient satisfaction for first- and second-eye surgeries. Results: Sixty-four patients (128 eyes) were included and analyzed (31 per group). Hyperalgesia was lower in the gabapentin pretreatment group than in the control group (4 [12.9%] vs. 17 [54.8%], risk ratio 0.24, 95% confidence interval 0.09–0.63, p = 0.001). Maximum intraoperative pain significantly decreased from the first to the second surgery in the gabapentin pretreatment group, whereas it increased in the control group (mean difference [standard deviation], −1.48 [2.14] vs. 0.97 [1.96], p < 0.001). Preoperative anxiety improved similarly in both groups before the second surgery. Conclusions: Gabapentin pretreatment may represent a promising strategy for reducing second-eye hyperalgesia and improving perioperative pain-related outcomes in older patients undergoing sequential bilateral cataract surgery under monitored anesthesia care with retrobulbar block.