High Frequency Jet Ventilation during Laryngeal Microsurgery : Effect of Inspiration Time and Frequency on the Gas Exchange / 대한마취과학회지

ABSTRACT

High frequency jet ventilation(HFJV) administered through a thin catheter instead of a standard endotracheal tube provides improved operation field during laryngeal microsurgery. In this study, effect of changes in inspiration time and frequency on gas exchange was observed. Sixty five patients(ASA class 1-2) underwent laryngeal microsurgery were divided into 3 groups according to inspiration time(50%, 40% and 30%) and then subdivided into 3 groups according to frequency(3.3 Hz, 2.5 Hz and 1.7 Hz). Driving pressure was same in all groups(2.4 kg, cm). Anesthesia was induced with thiopental sodium, fentanyl and succinylcholine with 100% oxygen mask ventilation and maintained with intermittent intravenous anesthetics during jet ventilation via 10 Fr. catheter with 100% oxygen. Jet cannular was located 1 cm proximal to carina. Arterial blood gas analysis and hemodynamic data(blood pressure and heart rate) were measured at 0 minute(just after catheter intubated and jet ventilation started), 5 minute, 10 minute and after then, every 10 minutes. There was significant change in PaCO; by varing inspiration time but, no significant change by frequency except in group of 3.3 Hz at inspiration time 40% and 30%. Number of patients who showed in excess of 45 mmHg of PaCO2 at 20 minute were 2 out of 19, 9 out of 23 and 9 out of 23 in inspiration time 50%, 40% and 30%, respectively. In summary, HFJV via thin catheter located 1 cm proximal to carina during laryngeal microsurgery can be done safely with inspiration time 50% under good operation field at driving pressure 2.4 kg/cm and frequency 3.3, 2.5 and 1.7 Hz.