Perioperative loss of the psoas major muscle area index in elderly patients with hip fracture: spinal anesthesia versus general anesthesia-a retrospective cohort study.

PURPOSE: In hip fracture patients aged ≥ 80 years, we investigated whether the perioperative reduction in the psoas major muscle index (PMI) for spinal anesthesia was less than that for general anesthesia. METHODS: A total of 262 patients surgically treated for intertrochanteric or femoral neck fractures between August 2015 and August 2022 were enrolled. After adjusting for propensity score matching, 50 patients were included in this analysis. After matching, patients were divided into those receiving spinal or general anesthesia. We measured the psoas major muscle area (PMA) by adjusting for the patient's height as PMA (cm2) divided by height (m) squared. The adjusted PMA was defined as the PMI. We calculated the variability in PMI (ΔPMI) before and after surgery. The primary outcome was the proportion of patients with a > 10% reduction in ΔPMI. The secondary outcomes were the mean ΔPMI and estimated factors affecting the postoperative reduction in the PMI. We compared the primary and secondary outcomes between spinal and general anesthesia. RESULTS: The proportion with a > 10% reduction in ΔPMI did not differ between spinal and general anesthesia (36.0% vs. 40.0%, odds ratio:1.19, 95% CI:0.38-3.72, p = 0.31). The ΔPMI did not differ between spinal and general anesthesia (- 8.7% ± 7.9% vs. - 8.9% ± 8.3%, p = 0.93). The factors affecting the postoperative reduction in the PMI were male sex, preoperative non-sarcopenia, and intramedullary nailing. CONCLUSION: There was no significant difference in ΔPMI between hip fracture patients ≥ 80 years of age receiving spinal versus general anesthesia undergoing surgical treatment.

Abnormally low regional cerebral oxygen saturation after induction of anesthesia without neurological abnormality: A case report.

Measurement of regional cerebral oxygen saturation (rSO2) using near-infrared spectroscopy (NIRS) in cardiac surgery is known to be useful in reducing postoperative neurological complications. We here present a case of a 71-year-old man in whom severe decrease in unilateral rSO2 was observed after induction of general anesthesia for percutaneous mitral valve clipping, although no neurological abnormalities were found. NIRS does not always predict postoperative neurological complications.

The effect of unilateral chest drainage for transpulmonary pressure during mechanical ventilation.

INTRODUCTION: Chest tube drainage is usually performed through an underwater seal at a level of 10-20 cmH2O. Based on the definition of transpulmonary pressure, continuous chest drainage creates continuous negative pressure, decreasing pleural surface pressure and increasing transpulmonary pressure. We investigated how unilateral chest drainage could affect the tidal volume or driving pressure during mandatory mechanical ventilation. METHODS: This study was an experimental study using a lung-thoracic model and anesthesia ventilator. Tidal volume was set to 300 mL with pressure-controlled ventilation or volume-controlled ventilation. Left tidal volume and right tidal volume were measured independently using respirometers with positive end-expiratory pressure (PEEP) levels of 0, 10, and 20 cmH2O. Simultaneously, left negative pressure of the chest drainage was changed to 0, 10, and 20 cmH2O. RESULTS: In all conditions, a tidal volume of 300 mL was achieved. In both pressure-controlled ventilation and volume-controlled ventilation, the left tidal volume increased with the application of chest drainage at 10 cmH2O when the PEEP level was 0 cmH2O, but left tidal volume decreased with the application of chest drainage at 20 cmH2O. Furthermore, when PEEP was 10 cmH2O, the left tidal volume decreased in proportion to the pressure of thoracic drainage. The right tidal volumes changed inversely with their counterpart left tidal volumes. CONCLUSION: Unilateral chest drainage caused unbalanced ventilation of the left and right lungs regardless of pressure-controlled ventilation or volume-controlled ventilation.

Total intravenous anesthesia management with simultaneous use of remimazolam and propofol: A case series of three patients.

Remimazolam is an ultra-short-acting benzodiazepine anesthetic agent. Because of pharmacodynamic interactions in the sedation effect between benzodiazepines and propofol, the combination of remimazolam and propofol may allow for a dose reduction of each agent while providing effective sedation for general anesthesia. We experienced three cases in which general anesthesia was induced with remimazolam and maintained with relatively small doses of remimazolam and propofol target-controlled infusion. In all cases, electroencephalogram changes associated with sedation induced by remimazolam were carefully observed during anesthesia induction before administration of propofol. The time required for recovery from anesthesia was 8-13 min. This is the first report in which remimazolam and propofol were concomitantly used for general anesthesia based on the concept of pharmacodynamic interaction. This anesthetic combination may be beneficial in reducing doses of each anesthetic and avoiding delayed recovery from anesthesia, although further study is needed to confirm this.

Effect of averaging time and respiratory pause time on the measurement of acoustic respiration rate monitoring.

BACKGROUND: Acoustic respiration rate (RRa) monitoring is a method of continuously measuring respiratory rate using a signal from an acoustic transducer placed over the airway. The purpose of the present study is to examine how the averaging time and respiratory pause time settings of an RRa monitor affect the detection time of sudden respiratory rate changes. METHODS: A total of 40 healthy adult volunteers were included in the study. First, we measured the apnea detection time (apnea test) by dividing them into two groups (N = 20 each), one with a respiratory pause time setting of 20 s and the other with 40 s. Each group performed two apnea tests with an averaging time setting of 10 and 30 s. Next, we measured the tachypnea detection time (tachypnea test) for half of the subjects (N = 20) with two averaging time settings of 10 and 30 s. For each test, three measurements were taken, and the average of the three measurements was recorded. RESULTS: There was no significant difference in the apnea detection time between the averaging time set at 10 and 30 s regardless of whether the respiratory pause time was set at 20 or 40 s. However, the apnea detection time was significantly shorter with the respiratory pause time of 20 s than 40 s, regardless of whether the averaging time was set at 10 or 30 s (p < 0.001). The tachypnea detection time was shorter with the averaging time of 10 s than 30 s (p < 0.001). Furthermore, the apnea detection time and tachypnea detection time were much longer than the actual settings. CONCLUSIONS: The results of the current study show that in the measurement of RRa, the apnea detection time is more affected by the respiratory pause time setting than the averaging time setting; however, the tachypnea detection time is significantly affected by the averaging time setting.