EFFECTS OF HYPERTONIC SALINE AND DEXTRAN-70 RESUSCITATION ON MICROVASCULAR PERMEABILITY AFTER BURN

Administration of hyperosmolar fluids to burn patients has been proposed as a means of decreasing resuscitative fluid volume and, subsequently, wound edema accumulation. To test this hypothesis, canine hindpaw lymph flow (Q(L)) and lymph (C(L)) and plasma (C(P)) total protein concentrations were measured, and capillary filtration coefficient (K(f)) was calculated before and for 6 h after a 5-s 100-degrees-C footpaw scald. Scald was followed 30 min later by bolus infusion (4 ml/kg) of 7% saline or 6% Dextran 70 or the two in combination. Before scald, venous pressure was elevated until a minimal C(L)/C(P) was reached. The reflection coefficient (sigma(d)) was calculated by the formula: 1 - minimal C(L)/C(P). Scald increased Q(L), C(L)/C(P), and K(f), but sigma(d) was decreased (P < 0.05). Compared with burn alone, 7% saline exacerbated burn-induced increases in Q(L) and K(f). In contrast, infusion of Dextran 70 did not exacerbate these changes in Q(L) or K(f). Perhaps more importantly, Dextran 70 may have attenuated the increase in C(L)/C(P) and reduced edema formation in the burned hindpaw. However, the addition of 7% saline to the dextran eliminated these beneficial effects.