Pressure-Controlled Ventilation Attenuates Lung Microvascular Injury in a Rat Model of Activated Charcoal Aspiration

Abstract

Background: Previous animal data suggest that aspiration of activated charcoal is associated with pulmonary microvascular injury that may be related to excessive ventilator-induced airway pressures. The purpose of this study was to test the hypothesis that ventilator-induced airway trauma contributes to the lung vascular injury observed following activated charcoal aspiration. Methods: Capillary filtration coefficient (Kf,c), a sensitive measure of lung microvascular permeability, was determined isogravimetrically prior to and after intratracheal instillation of 0.4 ml/kg (12% weight/vol. solution, pH 7.4) activated charcoal or an equal volume of sterile water in isolated, perfused rat lungs in which ventilation was either pressure-controlled at 10 cm H₂O or volume-controlled at 5 ml/kg. Results: There was significant lung injury in both activated charcoal groups regardless of ventilation method compared to control lungs or lungs administered sterile water (p<0.05 ANOVA). However, injury to pressure-controlled ventilated lungs was significantly less than lungs ventilated with traditional, volume-controlled ventilation. Conclusion: The results of this investigation demonstrate that pressure-controlled ventilation reduces the lung microvascular injury observed following aspiration of activated charcoal as compared to traditional volume-controlled ventilation methods.

Keywords :

• Activated charcoal
• Lung injury
• Aspiration