Accuracy of the Set Tidal Volume During Intraoperative Administration of Aerosols Into the Anesthetic Circuit: An In Vitro Evaluation

Abstract

Background: Precise control of minute ventilation is essential during the intraoperative anesthetic care of infants and children, as increased tidal volume (Vt) and consequently increased peak inflating pressure (PIP), may lead to volutrauma or barotrauma. During the intraoperative delivery of aerosolized medications such as albuterol, the additional flow required for delivery through nebulizers may alter Vt and secondarily PIP. The current study explores Vt changes during the use of a novel nebulizing device (Aerogen vibrating mesh) for the delivery of an aerosolized medication during mechanical ventilation.

Methods: Using a lung analogue model, this in vitro study compared the set Vt on the anesthesia ventilator to the internally measured inspiratory and expiratory Vt on the Avance CS2 anesthesia machine during both pressure-controlled (PC) and volume-controlled (VC) modes while administering aerosols using the Aerogen device.

Results: A total of 250 simulated breaths were delivered using the two modes of PC ventilation (PIP 15 and 20 cm H₂O) and VC ventilation (Vt of 150 and 300 mL). In both PC and VC modes, there were no clinically significant differences between the set and the inspiratory or expiratory Vt or PIP at baseline when compared to those achieved following the addition of a continuous aerosol using the Aerogen device.

Conclusions: The novel technology of the Aerogen vibrating mesh device allows the delivery of continuous aerosolized medications during intraoperative mechanical ventilation using a standard anesthesia circle system. The Aerogen device can be inserted between the Y-piece of the anesthesia circuit and the 15-mm adaptor of the endotracheal to easily allow the delivery of aerosolized medications without changes in mechanical ventilation parameters.