Background: There are several advantages of low flow anesthesia including safety, economics, and eco-friendliness. However, oxygen concentration of fresh gas flow and inspired gas are large different in low flow anesthesia. This is a hurdle to access to low flow anesthesia. In this study, we aimed to investigate the change in inhaled oxygen concentration in low flow anesthesia using oxygen and medical air. Methods: A total of 60 patients scheduled for elective surgery with an American Society of Anesthesiologist physical status I or II were enrolled and randomly allocated into two groups. Group H: Fresh gas flow rate (FGF) 4 L/min (FiO₂ 0.5). Group L: FGF 1 L/min (FiO₂ 0.5). FGF was applied 4 L/min in initial phase (10 min) after intubation. After initial phase FGF was adjusted according to groups. FGF continued at the end of surgery. Oxygen and inhalation anesthetic gas concentration were recorded for 180 min at 15 min interval. Results: The inspired oxygen concentration decreased by 5.5% during the first 15 min in the group L. Inspired oxygen decreased by 1.5% during next 15 min. Inspired oxygen decreased by 1.4% for 30 to 60 min. The inspired oxygen of group L is 35.4 ± 4.0% in 180 min. The group H had little difference in inspired oxygen concentration over time and decreased by 1.8% for 180 min. Conclusions The inspired oxygen concentration is maintained at 30% or more for 180 min in patients under 90 kg. Despite some technical difficulties, low flow anesthesia may be considered.

Background: The STOP-BANG questionnaire is a simple screening tool with high sensitivity for the detection of severe obstructive sleep apnea (OSA). Predicting airway obstruction would allow the safe management of sedative patients to prevent intraoperative hypoxia. This study was designed to check the correlation between the STOP-BANG score and oxygen saturation (SpO2) during sedation and confirm the availability of the STOP-BANG questionnaire as a preoperative exam for predicting the incidence of hypoxia in sedative patient management. Methods: This study included 56 patients who received spinal anesthesia. The pre-anesthesia evaluation was conducted using the STOP-Bang questionnaire. The patients were under spinal anesthesia with an average block level of T10. Dexmedetomidine was infused with a loading dose of 1 μg/kg over 10 min and a maintenance dose of 0.5 μg/kg/h until the end of the procedure. The SpO2 of the patients was recorded every 5 min. Results: The STOP-Bang score was negatively correlated with the lowest SpO2 (coefficient = –0.774, 95% confidence interval [CI]: –0.855 to –0.649, standard error [SE] = 0.054, P < 0.001). The item of “observed apnea” was the most correlated one with hypoxic events (odds ratio = 6.00, 95% CI: 1.086 to 33.145). Conclusions The STOP-BANG score was significantly correlated with the lowest SpO2 during spinal anesthesia, which enabled the prediction of meaningful hypoxia before it occurred in the sedated patients.

Objective: : Trigeminal neuralgia (TN) is a severe neuropathic condition that affects several elderly patients. It is characterized by uncontrolled pain that significantly impacts the quality of life of patients. Therefore, the condition should be treated as an emergency. In the majority of patients, pain can be controlled with medication; however, other treatment modalities are being explored in those who become refractory to drug treatment. The use of the trigeminal nerve block with a local anesthetic serves as an excellent adjunct to drug treatment. This technique rapidly relieves the patient of pain while medications are being titrated to effective levels. We report the efficacy and safety of percutaneous trigeminal nerve block in elderly patients with TN at our outpatient clinic. Methods: : Twenty-one patients older than 65 years with TN received percutaneous nerve block at our outpatient clinic. We used bupivacaine (1 mL/injection site) to block the supraorbital, infraorbital, superior alveolar, mental, and inferior alveolar nerves according to pain sites of patients. Results: : All patients reported relief from pain, which decreased by approximately 78% after 2 weeks of nerve block. The effect lasted for more than 4 weeks in 12 patients and for 6 weeks in two patients. There were no complications. Conclusion : Percutaneous nerve block procedure performed at our outpatient clinic provided immediate relief from pain to elderly patients with TN. The procedure is simple, has no serious side effects, and is easy to apply.