Measurement of extravascular lung water in sheep during colloid and crystalloid resuscitation from smoke inhalation.
The pathophysiology of pulmonary inhalation injury, a major cause of morbidity and mortality from fires, is poorly understood. To examine the effects of colloid and crystalloid resuscitation on extravascular lung water (EVLW) during a standard smoke inhalation injury, we subjected 12 sheep to 8 minutes of cool pine smoke inhalation. The animals were then resuscitated to a pulmonary capillary wedge pressure (PCWP) of 10 +/- 1.5 mm Hg with either lactated Ringer's solution or plasma protein derivative. EVLW, cardiac output, vascular resistance, colloid oncotic pressure (COP), arterial and pulmonary artery pressures, PCWP, and blood gases were monitored during 4 hours of resuscitation. In colloid-treated animals, EVLW increased from 8.3 +/- 1.2 to 11.1 +/- 0.9 ml/kg with injury; it increased only to 12.5 +/- 1.3 ml/kg during resuscitation. In crystalloid-treated animals, EVLW increased from 8.0 +/- 1.0 to 10.3 +/- 0.8 ml/kg with injury and further increased to 17.4 +/- 1.6 ml/kg during resuscitation, a level significantly higher than that in the colloid group (P less than 0.05). The increases in EVLW were associated with progressive hypoxia, which was worse in the crystalloid group. In the crystalloid group, COP decreased from 27.3 +/- 0.9 to 14.2 +/- 0.4 mm Hg and intravascular driving force (COP-PCWP) dropped from 17.6 to 3.26 +/- 1.5 mm Hg; COP and COP-PCWP were maintained in the colloid group. These data demonstrate that supporting serum COP minimizes the increase in EVLW with smoke inhalation injury and suggests that smoke inhalation does not lead to a dramatic increase in alveolar capillary membrane permeability to protein.