Supraglottic combined frequency jet ventilation versus subglottic monofrequent jet ventilation in patients undergoing microlaryngeal surgery

We compared the efficacy of gas exchange during supraglottic combined-frequency jet ventilation via a jet ventilation laryngoscope and during monofrequent jet ventilation via the Mon-Jet catheter (Xomed, Jacksonville, FL). Twenty-three anesthetized (propofol, fentanyl, vecuronium) patients undergoing microlaryngeal surgery were prospectively studied and randomly assigned to one of two groups. The patients' lungs were ventilated with combined-frequency jet ventilation (10 min, 15 and 600 breaths/min, inspiration/expiration time ratio = 1, driving pressure 750-1500 mm Hg), monofrequent (low-frequency group: 15 breaths/min; high-frequency group: 600 breaths/min) jet ventilation (20 min), and again combined-frequency jet ventilation (15 min). PaO2 PaCO2 and the inspiratory oxygen fraction (FIO2) were measured. Wilcoxon's signed rank test was applied. During monofrequent jet ventilation, PaCO2 increased and the PaO2/FIO2 decreased significantly (P < 0.05) as compared with combined-frequency jet ventilation (low-frequency group: PaCO2 from 39.4 +/- 3.3 to 50.8 +/- 8.0 mm Hg, PaO2/FIO2 from 306 +/- 100 to 225 +/- 94 mm Hg; high-frequency group: PaCO2 from 36.7 +/- 7.2 to 60.3 +/- 6.1 mm Hg, PaO2/FIO2 from 429 +/- 87 to 190 +/- 51 mm Hg; mean +/- SD). After switching back to combined-frequency jet ventilation, PaCO2 decreased and PaO2/FIO2 increased to baseline levels. We conclude that gas exchange during microlaryngeal surgery can be more easily maintained with supraglottic combined-frequency jet ventilation than with subglottic monofrequent jet ventilation via the Mon-Jet catheter. implications: This study demonstrates that the combination of high- and low-frequency supraglottic jet ventilation via a jet ventilation laryngoscope provides a better pulmonary gas exchange and allows more accurate airway pressure monitoring during microlaryngeal surgery than subglottic monofrequent jet ventilation via an endotracheal catheter.