Comparison of renal function following anesthesia with low-flow sevoflurane and isoflurane.

STUDY OBJECTIVE: To evaluate postoperative renal function after patients were administered sevoflurane under conditions designed to generate high concentrations of compound A. STUDY DESIGN AND SETTING: A multicenter (11 sites), multinational, open-label, randomized, comparative study of perioperative renal function in patients who have received low-flow (< or = 1 L/min) sevoflurane or isoflurane. PATIENTS: 254 ASA physical status I, II and III patients requiring endotracheal intubation for elective surgery lasting more than 2 hours. INTERVENTIONS: After induction, low-flow anesthesia was initiated at a flow rate < or = 1 L/min. Blood and urine samples were studied to assess postoperative renal function. MEASUREMENTS AND MAIN RESULTS: Measurements of serum BUN and creatinine, and urine glucose, protein, pH, and specific gravity were used to assess renal function preoperatively and up to 3 days postoperatively. Serum inorganic fluoride ion concentration was measured at preinduction, emergence, and 2, 24 and 72 hours postoperatively. Compound A concentrations were measured at two sites for those patients receiving sevoflurane. Adverse experience data were analyzed. One hundred eighty-eight patients were considered evaluable (98 sevoflurane and 90 isoflurane). Peak serum fluoride concentrations were significantly higher after sevoflurane (40 +/- 16 microM) than after isoflurane (3 +/- 2 microM). Serum creatinine and BUN decreased in both groups postoperatively; glucosuria and proteinuria occurred in 15% to 25% of patients. There were no clinically significant differences in BUN, creatinine, glucosuria, and proteinuria between the low-flow sevoflurane and low-flow isoflurane patients. CONCLUSIONS: There were no statistically significant differences in the renal effects of sevoflurane or isoflurane in surgical patients undergoing low-flow anesthesia for up to 8 hours. Low-flow sevoflurane anesthesia under clinical conditions expected to produce high levels of compound A appears as safe as low-flow isoflurane anesthesia.

Anesthesia for bronchoscopic laser surgery.

Choice of anesthesia for bronchoscopic laser surgery depends on the surgical technique. Fiberoptic bronchoscopy can be managed with either topical or general anesthesia, while rigid bronchoscopy usually requires general anesthesia. In either case precautions for laser surgery must be taken. Preoperative evaluations should include cardiovascular status and the anatomy of the lesion. Preoperative medication should include an anticholinergic agent. The influence of total intravenous vs. inhaled anesthetics on prolonged respiratory depression is discussed, and the techniques for providing controlled vs. spontaneous respiration are described. Finally, postoperative care, including the management of airway obstruction and hemorrhage, is outlined.

Comparison of tracheal damage from laser-ignited endotracheal tube fires.

Studies were undertaken by the Departments of Otolaryngology-Head and Neck Surgery and Anesthesiology at Northwestern University Medical School and the Medical College of Wisconsin (Milwaukee) to compare the potential for tissue injury to the trachea and lungs of canines. Polyvinylchloride (PVC), Rusch red rubber, and silicone tubes were tested. The effects of an intraluminal tube fire on the larynx and trachea were documented with laryngeal and bronchoscopic photographs taken immediately postburn and at the time of sacrifice six hours later. The most severe burns were associated with the PVC tube. Silica ash was seen in the airway after the silicone tube fires and raises the possibility of future problems with silicosis. Histological examination of the trachea showed acute injury in all of the animals; specimens from the dogs with the PVC tube fires demonstrated the most severe cellular damage.