A leading cause of iatrogenic anesthetic morbidity and mortality in small animal veterinary patients is pulmonary barotrauma.
Barotrauma has been shown to occur when airway pressures exceed as little as 30 cm of H2O but the threshold is species and likely breed specific. Once the airway pressure threshold is exceeded, alveoli rupture decreasing surface area for gas exchange. In severe cases the visceral pleura and large airways rupture leading to pneumothorax. The extreme intra-thoracic pressure also prevents venous return to the heart, ultimately leading to cardiac arrest.
There is no effective treatment for this injury other than mechanical ventilation and supportive care for extended periods of time.