Hypertonic saline as a resuscitation solution in hemorrhagic shock: effects on extravascular lung water and cardiopulmonary function.
To determine the effect of resuscitation with hypertonic saline on extravascular lung water, seven adult sheep were endotracheally intubated; mean arterial pressure (MAP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and central venous pressure (CVP) were monitored. A 5-French, thermistor-tipped catheter was used to measure extravascular lung water (EVLW). Colloid oncotic pressure (COP), serum electrolytes and osmolality, and arterial and mixed venous blood gas tensions were measured. The COP-PCWP gradient and the shunt fraction (Qsp/Qt) were calculated. After baseline measurements, the animals were bled to an MAP of 50 mm Hg (blood volume removed, 16.2 +/- 3.6 ml/kg), which was maintained for 30 min, measurements then being repeated. Three percent sodium chloride solution was infused at 500 ml/15 min until two of three parameters--cardiac output (CO), PCWP, or MAP--were restored to baseline values. Data were recorded again and then 60 min later. No shed blood was reinfused. The total volume of hypertonic saline infused was 39 +/- 19 ml/kg. Pulmonary artery pressure did not vary throughout the study. PCWP, MAP, and CO were significantly lower than baseline (P less than 0.05) 30 min after bleeding but all except MAP returned to baseline with resuscitation. Throughout the study, EVLW did not vary despite a COP-PCWP gradient less than 4 mm Hg. Serum sodium levels and serum osmolality were significantly above baseline values after resuscitation. In this animal model of hemorrhagic shock, infusion of hypertonic saline effected resuscitation without compromising cardiopulmonary function or increasing EVLW.