The twenty-degree reverse-Trendelenburg position decreases the incidence and severity of postoperative nausea and vomiting after thyroid surgery.

BACKGROUND: In this randomized, single-blind, controlled study, we evaluated whether the 20 degrees reverse-Trendelenburg position had an effect on postoperative nausea and vomiting in patients undergoing thyroid surgery. METHODS: Patients (n = 224) were given a standardized propofol anesthetic. Intraoperatively, patients were randomly assigned into two groups according to the tilt of the table maintained during surgery: patients were positioned with the neck extended and the table tilted with 20 degrees reverse-Trendelenburg or with the neck extended and the table positioned at a horizontal tilt. All episodes of postoperative nausea, vomiting, nausea severity score, frequency of vomiting, and the use of antiemetics were recorded during the first 24 h after anesthesia. We divided this time period into 0-3 h and 3-24 h. RESULTS: During the 0-3 h postoperative period, all observed episodes were comparable between groups. However, during the 3-24 h and the overall postoperative period, the incidence of nausea and/or vomiting, the nausea severity score, and frequency of vomiting were significantly less in the 20 degrees reverse-Trendelenburg position. CONCLUSION: The 20 degrees reverse-Trendelenburg position effectively ameliorates postoperative nausea and/or vomiting.

[Relationship between driving pressure and tidal volume during high frequency jet ventilation for the tracheal resection].

BACKGROUND: High frequency jet ventilation (HFJV) is a method of ventilation for tracheal resection because it provides a good surgical field and decreases surgical complications. We should know ventilatory settings of HFJV to perform safe respiratory management. In this study we evaluated the relationship between tidal volume (VT) and driving pressure (DP) during HFJV for tracheal resection. METHODS: Twenty patients undergoing tracheal resection under total intravenous anesthesia were studied. Jet pulse was delivered through a 12 or 15 Fr feeding catheter connected to a jet ventilator. We set DP optionally and inspired oxygen concentration 100%, ventilatory frequency 100 x min(-1), and I/T ratio 0.3 or 0.5. In fourteen patients receiving HFJV with 15 Fr catheter we calculated VT by measured PaCO2, reported VCO2 value, and physiological dead space (1.1 x body weight) for each patient and evaluated relationship between VT and DP. RESULTS: HFJV was feasible in all patients. Pneumothrax occurred in one patient. Respiratory complications including pneumonia and respiratory failure were not observed after surgery in all patients. The calculated VT values showed a significant correlation with DP (VT = 48.1 DP + 44.7, r=0.73, P<0.01). CONCLUSIONS: In respiratory management for tracheal resection with HFJV, we can predict DP from VT calculated by expected PaCO2, reported VCO2 value, and physiological dead space. It enables us to perform safe respiratory management.

[Concentrations of sevoflurane with and without nitrous oxide to block vasomotor reflexes to incision (MACBVR)].

The minimum alveolar concentration of an anesthetic that blocks the skin vasomotor reflex to surgical incision (MACBVR) for sevoflurane was determined in 37 patients aged 30-60 years scheduled for laparotomies with or without nitrous oxide. Thirty seven patients were randomly allocated to one of the two groups: a sevoflurane group and a sevoflurane/N2O (50 vol%) group. The skin blood flow of the finger tip was measured using a laser Doppler flowmeter. Anesthesia was induced with sevoflurane and N2O and tracheal intubation was facilitated with vecuronium 0.1 mg.kg-1. Predetermined end tidal concentrations of sevoflurane and N2O were maintained for at least 15 min before incision. The MACBVR values of sevoflurane in O2 and in the presence of 50% N2O were 3.07% and 1.63%, respectively. The MACBVR level in the total anesthetic MAC multiple was 1.75 MAC for sevoflurane alone and the value decreased to 1.43 MAC when 50% N2O was used. There were no relations between the amplitude of the reduction in skin blood flow and the changes of hemodynamic variables in each group. However, the changes in SBP and HR at incision were significantly suppressed by addition of N2O (changes in SBP and HR: 41.6 +/- 20.4 mmHg and 35.4 +/- 12.5 bpm in the sevoflurane group vs. 24.6 +/- 10.2 mmHg and 18.1 +/- 9.5 bpm in the sevoflurane/N2O group, P < 0.01). The results suggest that N2O is useful to suppress adrenergic responses to a surgical stimulus during sevoflurane anesthesia.