Manual translaryngeal jet ventilation and the risk of aspiration in a canine model

Study objectives: Manual translaryngeal jet ventilation (TLJV) is a safe and effective method of maintaining normal ventilation in apneic subjects. Little data exist on the amount of airway protection afforded with this technique of airway management. We sought to evaluate the risk of aspiration during manual TLJV. Setting: Data were collected in a laboratory animal model. Design: A prospective, nonrandomized, controlled trial was performed. Participants: Seventeen adult apneic mongrel dogs were enrolled. Interventions: Intratracheal Gastrograffin^® was instilled and radiographic changes assessed during ventilation using a 0 to 3 scale (none to severe). Thirty-six trials were performed, with equal numbers at both 30° and 45° head elevation. The three groups studied were animals without airway protection (control), animals with a cuffed endotracheal tube (tube), and animals with a percutaneous TLJV cannula and a 50-psi oxygen source ventilated at a rate of 20 breaths per minute (jet). Measurements and main results: Significantly less radiographic evidence of aspiration was noted in the jet and tube groups at 30° and 45° compared with control animals (P = .002 each). At 45° head elevation a trend toward increased aspiration scores in the jet group compared with the tube group (P = .065) was observed. Conclusion: In our model, manual TLJV at 20 breaths per minute and an I:E ratio of 1:2 provided protection from aspiration comparable to that observed with a cuffed endotracheal tube at 30° head elevation. At 45° elevation, this protection was diminished.