Iatrogenic tension pneumothorax in a rabbit (Oryctolagus cuniculus)

The following case report describes a complication after accidental overinflation of the lungs in an anesthetized rabbit. After anesthetic induction, endotracheal intubation, and preparation for surgery, the rabbit's arterial oxygen saturation dropped. Positive-pressure ventilation was administered using manual compression on the reservoir bag. The rabbit's condition rapidly deteriorated, and emergency treatment including oxygen, anesthetic reversal, and thoracocentesis was initiated. The rabbit failed to respond to therapy. A focal, acute, alveolar, vascular, and pleural rupture of the right caudal medial lung lobe with secondary pulmonary tension pneumothorax and atelectasis was identified postmortem. The etiology and pathophysiology of the clinical signs are reviewed. Pulmonary pressure overload after manual or assisted ventilation and subsequent stress failure occurs when pulmonary pressures approach 40 mm Hg. Close attention to the animal's size, tidal volume, and potentially altered pulmonary elasticity from pre-existing lung disease may help reduce the incidence of failure. Successful therapy of iatrogenic pneumothorax may necessitate both medical and surgical intervention.