Comparison of the Effects of Desflurane, Sevoflurane, and Propofol on the Glottic Opening Area during Remifentanil-Based General Anesthesia Using a Supraglottic Airway Device.

PURPOSE: The aim of this study was to compare the effects of desflurane, sevoflurane, and propofol on the glottic opening area during general anesthesia using remifentanil. METHODS: Ninety patients undergoing hand and upper limb surgery combined with brachial plexus block under general anesthesia were enrolled in the study. The patients were randomized into three groups to receive desflurane (group D), sevoflurane (group S), or propofol (group P) for maintenance of anesthesia. Following induction of general anesthesia with remifentanil, continuous fiberoptic video recording around the glottis via an i-gel™ supraglottic device was started after establishing mechanical ventilation. Desflurane, sevoflurane, or propofol was administrated after video recording was started. The changes in normalized glottic opening area (n-GOA) and peak inspiratory pressure (PIP) during surgery were compared between the three groups. RESULTS: Intraoperative changes of n-GOA in group D showed significant differences compared with group S and group P (-0.0656 ± 0.0772 vs. -0.0076 ± 0.0499 and +0.0269 ± 0.0809, P=0.005 and P < 0.0001). The changes of PIP in group D showed significant differences compared with group S and group P (+3.7 ± 3.4 cmH2O vs. +1.0 ± 1.3 cmH2O and -0.3 ± 3.6 cmH2O, P=0.002 and P < 0.0001). Four cases of relapsed glottic stenosis in group D were improved by changing desflurane to propofol. CONCLUSIONS: Desflurane narrowed the n-GOA and increased the PIP compared to sevoflurane and propofol during general anesthesia with remifentanil. Clinicians should be aware of the possibility of glottic stenosis during desflurane-remifentanil anesthesia when the airway is secured by a supraglottic airway device without the use of neuromuscular blockade.

[In vitro response time of continuous cardiac output measurement in STAT mode of Vigilance after controlled flow change].

BACKGROUND: Continuous cardiac output measurement in STAT mode (STAT CCO) equipped with Vigilance displays cardiac output every 30 to 60 seconds. The aim of this study is to verify the hypothesis that each value with this system is computed only from the data collected in one update period. METHODS: The circuit was filled with normal saline and flowed by a roller pump in in vitro setting. The flow rate was set at either 2.5 l x min(-1) or 5.0 l x min(-1) and changed quickly to another state after each state had been maintained for 25 minutes. The change operation was repeated 10 times. The maximum difference was defined as the difference between the value at the start and the maximum change value. The response time was defined as the time from the start to the time to reach 80% of the maximum difference. In each operation, the response time of STAT CCO was calculated. RESULTS: The response time of STAT CCO was 9.7 +/- 1.3 min (mean +/- SD). CONCLUSIONS: The response time of STAT CCO was about 10 times longer than one update period. This result suggests that STAT CCO values are not computed only from the data collected in one update period.

Distance from the skin to the epidural space at the first lumbar interspace in a Japanese obstetric population.

We prospectively examined the distance from the skin to the epidural space (SE distance) in 95 Japanese parturient women who underwent epidural anesthesia at the L1-2 interspace, and studied the correlation between various physical factors and SE distance. The same anesthesiologist inserted the epidural tubing with the patient in the right lateral decubitus position. An epidural needle was introduced into the skin vertically via the midline approach. The epidural space was located using the loss-of-resistance technique. SE distance was measured to the nearest 0.5 cm using centimeter markings on the shaft of the epidural needle. The median value of SE distance was 3.5 cm, with a range of 2.5 to 6.5 cm, and in 80% of cases SE distances were 3 to 4 cm. The correlation of body weight with SE distance was the highest of the physical factors (r2 = 0.800, p = 0.0001), and a simple regression equation was formulated to aid in predicting SE distance: "SE distance (cm) = 0.05 x body weight (kg) + 0.36". This formula will be a useful clinical guide for administering epidural anesthesia in Japanese parturient women. In conclusion, the SE distance in most Japanese parturient women is between 3 and 4 cm at the L1-2 interspace and this value is most closely correlated with their body weight.