Airway Stenosis-Related Increase of Pulmonary Pressure During High-Frequency Jet Ventilation Depends on Injector’s Position

Abstract

This study in a lung model suggests that placing an injector more than 8 cm proximal to a laryngotracheal stenosis will prevent changes in intrapulmonary pressure related to the degree of stenosis or driving pressure during HFJV. The location of the injector chosen for clinical care should balance the need for effective ventilation with the risk of barotrauma.

Influence of Tracheal Obstruction on the Efficacy of Superimposed High-frequency Jet Ventilation and Single-frequency Jet Ventilation

“…From their results from bench studies, some claim that detrimental intrapulmonary pressures occur during prestenotic JV, 32,33 whereas others report intrapulmonary pressures within acceptable limits. Although we noted a concomitant underestimation of intrapulmonary PEEP, we believe that prestenotic JV with (1) a jet injector position at sufficient distance from the stenotic segment 35 and (2) airway pressure monitoring more than 6 cm distal of the jet injector 36 help prevent inadvertently high intrapulmonary peak pressure and its complications in subjects with severe airway obstruction. Although we noted a concomitant underestimation of intrapulmonary PEEP, we believe that prestenotic JV with (1) a jet injector position at sufficient distance from the stenotic segment 35 and (2) airway pressure monitoring more than 6 cm distal of the jet injector 36 help prevent inadvertently high intrapulmonary peak pressure and its complications in subjects with severe airway obstruction.…”

Experimental model of laryngotracheal stenosis in infants: effects of different high‐frequency jet ventilation patterns on pulmonary parameters

“…A previous report by Ihra et al. (19) demonstrated in an adult trachea–lung model that the distance between the jet nozzle and the airway stenosis influences airway pressure, so that airway pressures decrease with increasing distance to the stenosis.…”

Considering the measurement of pressures generated during jet ventilation

“…Such pressures are common and necessary to overcome the high resistance associated with the application of normal tidal volumes via small bore cannulae and catheters and to facilitate effective gas exchange during HPSV. Although I completely agree with Hamaekers' general remarks on the safety issues of jet ventilation, especially on the underestimated risk of self-assembled jet devices, it would have been helpful to determine real airway pressures in an appropriate test system (5). Finally, PACT must not be interpreted as airway pressure.…”