Comparison of the clinical performances of Air-Qsp and i-Gel for airway management under general anesthesia with a muscle relaxant.

STUDY OBJECTIVES: Recently, i-Gel intubating laryngeal airway (ILA) has been frequently used because of the ease for airway insertion by residents and young anesthesiologists. However, it sometimes fails to fit or ventilate sufficiently in Japanese patients. Use of Air-Qsp, which is a new non-inflatable cuffed ILA, in a clinical setting has become possible. The purpose of this study was to compare the clinical performance of Air-Qsp with that of i-Gel for airway management in Japanese adult patients. DESIGN: A randomized, single-blinded, prospective study was conducted after approval from the institutional review board. SETTING: Operating rooms at hospitals. PATIENTS: Thirty-seven adult patients aged 20 to 69 years, with ASA physical status I or II, and scheduled for elective surgery under general anesthesia in the supine position. INTERVENTIONS: Patients were randomly assigned to insertion with Air-Qsp (Group A: n=20) or i-Gel (Group I: n=17). MEASUREMENTS: The number of insertions, duration of insertion, changes in systolic blood pressure and heart rate during insertion, delivered tidal volume for setting volume control ventilation, distribution of the tips of the bronchofiberscopes (BFs) on a clock face, and the number of postoperative complications was evaluated. MAIN RESULTS: Two patients in Group A and one patient in Group I were excluded because insertion of the device failed. There were no significant differences in measured parameters between the 2 groups. The distribution of the tips of the bronchofiberscopes tended to be around the center of the glottis in Group A, whereas they were more toward the 6-o'clock position in Group I. CONCLUSIONS: Air-Qsp is as useful as i-Gel in Japanese patients and the distributions of the tips of BFs through ILAs are different for Air-Qsp and i-Gel.

Effect of Intraoperative Glucose Infusion on Catabolism of Adipose Tissue and Muscle Protein in Patients Anesthetized With Remifentanil in Combination With Sevoflurane During Major Surgery: A Randomized Controlled Multicenter Trial.

BACKGROUND: A harmful effect of stress hormone secretion during surgery is lipolysis and proteolysis to maintain normal blood glucose levels. A well-titrated general anesthetic improves blood glucose control by suppressing secretion of these stress hormones. The aim of this study was to explore the effect of intraoperative glucose infusion on lipolysis and proteolysis in patients undergoing a general anesthetic consisting of sevoflurane and remifentanil during long (>6 hours) major surgery. METHODS: In this prospective, single-blinded, randomized, multicenter trial, 80 patients with an expected duration of anesthesia of >6 hours were allocated to either the glucose group, consisting of 40 patients who were infused with acetated Ringer's solution with glucose (2 mg/kg/min), or the no glucose group, consisting of 40 patients who were infused with the same solution, but without glucose. After oxygenation, general anesthesia was induced with propofol, fentanyl, and rocuronium and was maintained with sevoflurane, oxygen, rocuronium, and remifentanil infusions. The rates of remifentanil infusion were titrated based on systolic arterial blood pressure, maintaining this parameter within 10% of its postanesthesia values. Seventy-four patients completed the study. Urinary 3-methylhistidine/creatinine (3-MH/Cre) ratio, acetoacetic acid, 3-hydroxybutyric acid, blood glucose, insulin, and cortisol were measured 3 times: at anesthesia induction (0 hour) and at 3 and 6 hours after anesthesia induction. Urinary 3-MH/Cre ratio was the primary study outcome. RESULTS: In the no glucose group, the urinary 3-MH/Cre ratio at 6 hours was increased compared with that at 0 hour (213 [range, 42-1903] vs 124 [18-672] nmol/µmol; the difference in medians, 89; the 95% confidence interval [CI] of the difference, 82-252; P = .0002). Acetoacetic acid and 3-hydroxybutyric acid levels in the no glucose group were greater than those in the glucose group at 6 hours (110 [8-1036] vs 11 [2-238] µmol/L; the difference in medians, 99; the 95% CI of the difference, 92-196; P < .0001 and 481 [15-2783] vs 19 [4-555] µmol/L; the difference in medians, 462; the 95% CI of the difference, 367-675; P < 0.0001, respectively). Blood glucose and insulin levels in the glucose group were greater than those in the no glucose group at 3 hours (146 [103-190] vs 93 [72-124] mg/dL; the difference in medians, 53; the 95% CI of the difference, 47-55; P < .0001 and 9.8 [1.2-25.4] vs 3.2 [0.4-15.0] µU/mL; the difference in medians, 6.5; the 95% CI of the difference, 4.8-6.8; P < .0001) and 6 hours (139 [92-189] vs 87 [68-126] mg/dL; the difference in medians, 52; the 95% CI of the difference, 44-58; P < .0001 and 8.1 [1.2-22.3] vs 3.2 [0.4-10.1] µU/mL; the difference in medians, 4.9; the 95% CI of the difference, 4.0-5.9; P < .0001). Cortisol levels in both groups were similarly within normal levels at 0, 3, and 6 hours. CONCLUSIONS: The study showed that intraoperative glucose infusion suppressed lipolysis and proteolysis in patients anesthetized with remifentanil in combination with sevoflurane during surgery of >6 hours in length.

Intravenous droperidol causes a reduction in the bispectral index in propofol-sedated patients during spinal anesthesia.

UNLABELLED: We investigated the effect of IV droperidol on the bispectral index (BIS) in conscious and propofol-sedated patients during spinal anesthesia. Thirty minutes after the induction of spinal anesthesia, 20 patients were given 2 mg of droperidol IV without administration of other sedatives (conscious group). Another group of patients were sedated with a propofol infusion to maintain BIS at 60 +/- 5 and were administered IV saline (placebo group; n = 20), droperidol 1 mg (dro-1 group; n = 20), or droperidol 2 mg (dro-2 group; n = 20) in a randomized order and in a double-blinded fashion. Although BIS remained the same in the conscious and placebo groups, it significantly decreased after administration of droperidol in the dro-1 and dro-2 groups. The decrease in BIS was significantly larger in the dro-2 group than in the dro-1 group. These results suggest that an antiemetic dose of droperidol enhances the hypnotic effect of propofol in a dose-dependent manner during spinal anesthesia. IMPLICATIONS: An antiemetic dose of IV droperidol causes a decrease in the bispectral index in patients sedated with propofol during spinal anesthesia. We conclude that droperidol may enhance the hypnotic effect of propofol.

[Effect of nitrous oxide on the bispectral index during sevoflurane anesthesia].

We studied the effects of nitrous oxide on the relationship between end-tidal sevoflurane concentration and bispectral index (BIS) in patients undergoing abdominal surgery. Anesthesia was maintained with combination of epidural and sevoflurane anesthesia in air (control group; n = 15) or with 67% nitrous oxide (nitrous oxide group; n = 15). The end-tidal sevoflurane concentration was increased by 0.5% every 15 min to 3% and BIS values were recorded at each step. In both groups, sevoflurane decreased BIS values in a dose-dependent manner and the decrease in BIS reached plateau at 2% of sevoflurane. Nitrous oxide with sevoflurane caused more reduction in BIS in comparison with sevoflurane alone. The sevoflurane concentration for BIS at 50 in the nitrous oxide group (0.9 +/- 0.4%) was significantly lower than that in the control group (1.2 +/- 0.4%). The results suggest that the hypnotic effect of sevoflurane was enhanced by the addition of nitrous oxide during abdominal surgery.

The bispectral index response to tracheal intubation is similar in normotensive and hypertensive patients.

PURPOSE: To compare the hemodynamic and bispectral index (BIS) responses to tracheal intubation in normotensive and hypertensive patients. METHOD: Three minutes after induction of anesthesia with thiamylal and fentanyl, tracheal intubation was performed in 24 normotensive and 22 hypertensive patients. Heart rate (HR), mean arterial pressure (MAP), and BIS were measured every minute. RESULTS: Tracheal intubation increased HR, MAP, and BIS in both normotensive and hypertensive patients. The increase in MAP was significantly greater in hypertensive patients than in normotensive patients, but there were no differences in HR or BIS in the two groups of patients. CONCLUSION: Patients with and without hypertension exhibit the same arousal response (as measured by BIS) to tracheal intubation despite the enhanced vasopressor response in hypertensive patients.

The effect of fentanyl on hemodynamic and bispectral index changes during anesthesia induction with propofol.

STUDY OBJECT: To investigate the changes in hemodynamics and hypnotic levels during propofol infusion and tracheal intubation with and without fentanyl. DESIGN: Randomized, double-blinded study. SETTING: Teaching hospital. PATIENTS: 40 ASA physical status I adult patients scheduled for elective surgery. INTERVENTIONS: Patients were anesthetized with either propofol (Group P; n = 20) or 2 microg/kg of fentanyl IV followed by propofol (Group PF; n = 20). Propofol was infused at 20 mg/kg/hr throughout the study, and tracheal intubation was performed 10 minutes after the start of propofol infusion. MEASUREMENT AND MAIN RESULTS: Bispectral index monitoring (BIS) progressively decreased to about 50 in both groups during infusion of propofol, but no difference was found between the two groups. After tracheal intubation, BIS significantly increased but remained below 60 in both groups. Hypertensive responses to intubation were fewer in Group PF than Group P. CONCLUSIONS: Propofol administration 20 mg/kg/hr for 10 minutes is suitable in suppressing arousal reactions to tracheal intubation, but the addition of fentanyl is required to blunt the hemodynamic responses.

Monitoring of skeletal muscle oxygenation using near-infrared spectroscopy during abdominal aortic surgery.

PURPOSE: To examine the utility of near-infrared spectroscopy (NIRS) in assessing lower-leg perfusion, NIRS was performed on the calf muscles of patients who underwent abdominal aortic surgery. METHODS: Thirty patients undergoing elective infrarenal abdominal aortic surgery for abdominal aortic aneurysm (AAA group; n = 16) and aorto-occlusive disease (AOD group; n = 14) were studied. Before induction of anesthesia, NIRS probes were placed over both calf muscles, and muscle oxygen saturation (S(tO2)) was continuously monitored throughout the surgery. RESULTS: The preoperative S(tO2) value was significantly lower in the AOD group (57.0 +/- 11.2%) than in the AAA group (68.7 +/- 7.0%). In both groups, S(tO2) significantly decreased after aortic cross-clamping; the maximal ischemic value of S(tO2) in the AAA group (17.8 +/- 7.2%) was significantly lower than that in the AOD group (46.7 +/- 17.1%). The time taken to reach maximal ischemia was significantly longer in the AAA group (30 +/- 12 min) than in the AOD group (19 +/- 12 min). After release of the aortic clamp, the decreased S(tO2) returned to the preoperative level in the AAA group, whereas it increased above the preoperative value in the AOD group. CONCLUSION: NIRS performed on the calf muscles is a useful method for assessing the changes in lower-leg perfusion during and after abdominal aortic surgery.