Humidity of Inspired Gases in Partial Rebreathing Anesthesia Method with and without Bird Humidifier / 대한마취과학회지

ABSTRACT

BACKGROUND: Adequate humidification of anesthetic gases has been recommended both for the prevention of pulmonary damage during endotracheal anesthesia and for the maintenance of body temperature, especially in long-duration operated patients. Partial rebreathing anesthesia technique frequently lacks adequate humidity. So, this study was designed to compare inspired humidities in partial rebreathing anesthesia method with and without humidifier in the system. METHODS: The author examined inspired humidity using a controlled partial rebreathing anesthesia method with and without Bird humidifier in 10 and 22 healthy adult patients respectively. The patients were divided into two groups (1 and 2). All patients were anesthetized with pancuronium, halothane or enflurane, nitrous oxide-oxygen, 50-50 per cent, and their lungs were mechanically ventilated. Inspired humidity was measured for three hours at 30-min intervals in both groups. RESULTS: Significant differences were found among group 1- and 2-inspired humidities for 3 hours. While group 2-inspired humidity remained constant between 13 and 16 mgH2O/L during entire anesthesia procedure group 1-inspired humidity remained under 9 mgH2O/L. CONCLUSIONS: The humidities in all partial rebreathing anesthesia method with Bird humidifier not only exceeded those of method without humidifier but also seemed to be high enough to prevent dysfunction of tracheobronchial ciliated epithelium, while the standard partial rebreathing anesthesia method does not provide adequate inspired humidity.