EFFECTS OF GRADED THERMAL-INJURY ON MICROVASCULAR PERMEABILITY AT THESITE OF INJURY

To define whether capillary permeability traits at the site of a burn differ according to injury severity, a canine hind leg lymphatic was c annulated to measure macromolecular permeability in response to three different scalding solutions. Leg venous pressure was raised to approx imate to 40 mm Hg and maintained until a minimal lymph-to-plasma total protein ratio (C-L/C-P)(min) and steady-state lymph flow (Q(L); mu l/ min/100 g) was attained. The protein reflection coefficient (1 - C-L/C -P), fluid filtration coefficient (K-f; mu l/min/mm Hg/100 g), and Q(L ) were determined before and for 6 hr after a B-sec hind paw immersion in either 100 degrees C (n = 7), 80 degrees C (n = 7), or 70 degrees C (n = 7) water. A group of five animals served as controls. In the ab sence of any systemic hemodynamic alterations, the 100 and 80 degrees C scald groups experienced significant (P < 0.05, ANOVA) increases in Q(L), C-L/C-P, and K-f as compared to respective preburn values and ti me-matched unburned control values. Most monitored parameters were sig nificantly higher following 100 degrees C injury vs 80 degrees C injur y. Parameters in the 70 degrees C group did change after scald, but we re not significantly different from preburn values or from the control group. Alterations in capillary permeability to protein and fluid flu x measured at the burn site are graded, not all or none phenomena, bei ng dependent upon the severity of injury. (C) 1994 Academic Press, Inc .