title: Thermal skin injury: effect of fluid therapy on the transcapillary colloid osmotic gradient.
abstract: The effects of fluid therapy on interstitial colloid osmotic and hydrostatic pressures in thermally injured skin were investigated in anesthetized rats subjected to full-thickness scald burns to 40% of the body surface area and resuscitation for 3 hr by either lactated Ringer's or plasma. Interstitial fluid hydrostatic pressure (Pif) was reduced from -2 mm Hg to -20 to -40 mm Hg after injury, which will profoundly increase transcapillary filtration. Following the onset of fluid therapy, Pif increased to slightly positive values. In control, colloid osmotic pressure in plasma (COPp) was 20.6 +/- 0.4 mm Hg and in interstitial fluid (COPif) 13.7 +/- 0.3 mm Hg (means +/- SEM). The transcapillary oncotic pressure gradient (COPgrad = COPp-COPif) was 6.9 +/- 0.4 mm Hg. Following nonresuscitated thermal injury, COPp declined to 18-19 mm Hg (P less than 0.05) and COPif was reduced to 10.4 +/- 0.5 mm Hg (P less than 0.05). Fluid therapy by lactated Ringer's markedly reduced COPp (12.3 +/- 0.3 mm Hg; P less than 0.05), and COPgrad was almost abolished (2.6 +/- 0.7 mm Hg; P less than 0.05). In contrast, plasma infusion maintained COPp, whereas COPgrad increased significantly (11.1 +/- 1.2 mm Hg; P less than 0.05). Noncolloid saline solutions have been preferred for the initial fluid therapy for burns. The present study provides evidence that this will reduce both COPp and COPgrad, a situation in which edema formation will be favored.
authors.affiliation: Department of Physiology, University of Bergen, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Onarheim
authors.forename: R K
authors.initials: RK
authors.lastname: Reed
mesh_terms: D000818:Animals; D002056:Burns / Q000378:metabolism / Q000628:therapy*; D002196:Capillaries / Q000378:metabolism*; D003102:Colloids / Q000378:metabolism*; D005110:Extracellular Space / Q000502:physiology; D005440:Fluid Therapy; D006874:Hydrostatic Pressure; D008297:Male; D009995:Osmosis; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000293:injuries*
chemical_list: D003102:Colloids