Early pulmonary and hemodynamic effects of a chest wall burn (effect of ibuprofen)

The cardiopulmonary effects of a third-degree scald burn involving the anterolateral chest wall was compared with a burn of equal size (30% of total body surface) to the flanks in anesthetized sheep with lung lymph fistulas. The chest-burn group was characterized by immediate decreases in cardiac output (6.5 to 3.0 L/min), central venous pressure (5 mm Hg to 0 mm Hg), pulmonary wedge pressure (10 mm Hg to 6 mm Hg), and urine output 1.5 ml/kg/hr to less than 0.5 ml/kg/hr. The temperature of pulmonary artery blood increased from 38 to 42 degrees C and plasma prostacyclin increased from 20 to 200 pg/ml. These changes were significantly different from those seen in the body sheep with burns. Initial fluid requirements necessary to restore filling pressures were 50% greater in the sheep with chest burns than in the sheep with body burns. An early decrease in static lung compliance was also seen after chest burn that was not the result of increased lung edema. A progressive decrease in compliance, urine output, and stroke output was also seen in the later postburn period (6 to 7 hours), which was significantly improved by a chest wall escharotomy. Postmortem analysis in the chest-burn group revealed a significantly increased malondialdehyde content, a reflection of increased oxygen radical-induced lipid peroxidation relative to the body burn. Pretreatment of the chest burn with ibuprofen, 12.5 mg/kg, prevented the initial vasodilator and lung compliance changes so that early cardiopulmonary status was identical to that seen with a body burn alone. Ibuprofen also decreased the lung tissue malondialdehyde content. We conclude that a burn involving the chest wall results in cardiopulmonary abnormalities, not seen after a body burn of a comparable size, which appear to be due to hyperthermia and an increased release of prostacyclin and O2 radicals.