Cardiogenic and obstructive shock: Case

This adolescent has developed a tension pneumothorax on the right side while ventilated for severe asthma. The sudden hypotension, tachycardia, desaturation, high ventilator airway pressures, absent right-sided breath sounds, and distended neck veins are the classic presentation of tension pneumothorax in a ventilated patient. Positive-pressure ventilation converts a simple pneumothorax to a tension pneumothorax rapidly, and this is a time-critical emergency requiring immediate decompression. ^[1][7]

Clinical findings

The pattern is that of obstructive shock from tension pneumothorax. The rising intrathoracic pressure from the trapped air has collapsed the right lung, pushed the mediastinum to the left, compressed the great vessels, and blocked venous return to the heart. The distended neck veins reflect the backed-up venous return, the hypotension reflects the loss of preload, and the high ventilator pressures and desaturation reflect the collapsed lung and the compressed pulmonary vasculature. The diagnosis is clinical in this scenario and imaging must not delay treatment. ^[1]

The differential at the moment of deterioration includes a blocked or displaced endotracheal tube, which can produce similar high pressures and desaturation, but the unilateral absent breath sounds and the distended neck veins point to tension pneumothorax. A mucus plug causing right lung collapse can also produce unilateral absent sounds, but it would not typically cause the distended neck veins and the sudden haemodynamic collapse. ^[7]