The pathophysiology of primary blast injury and its implications for treatment. Part I: The thorax.

There is insufficient evidence to support a definitive approach to the clinical management of primary pulmonary blast injury. Post-blast cardiovascular and pulmonary changes are reviewed in this paper in order to highlight important aspects in the immediate management of the blast injured casualty. Blast profiles and theoretical mechanisms of injury vary widely but all result in mechanical disruption and cause similar pathological, physiological and biochemical responses. Some patients may present acutely, while others appear unharmed and develop respiratory failure 12-24 hours later. Treatment outcome may depend on the judicious use of resuscitative fluids and respiratory support. The roles of supplementary oxygen and assisted ventilation remain controversial although administration of high inspired oxygen concentrations and respiratory support may be unavoidable. The advantage of pharmacological manipulation of reflex mechanisms is as yet unproven. Hyperbaric therapy may improve survival in pulmonary blast injury.