Hypertonic saline resuscitates dogs in endotoxin shock

Abstract

In this experiment we determined if infusions of hypertonic saline (HS, 1080 Na meq/liter) could resuscitate dogs in endotoxin shock as effectively as Ringer's lactate (RL, 130 Na meq/liter). Anesthetized dogs received iv 0.5 mg/kg of Escherichia coli endotoxin, and mean arterial pressure (MAP, mm Hg) decreased from 148 ± 5 to 58 ± 14 within 30 min. To resuscitate the dogs 13 meq/kg of sodium was intravenously infused over 90 min as either a 10% body weight load of RL ( n = 5) or a 1.2% body weight load of HS ( n = 5). Both solutions produced an equivalent hemodynamic resuscitation 3 to 4 hr postinfusion with an increase in MAP (RL, 119 ± 4; HS, 108 ± 7), the restoration of cardiac outputs to baseline (RL, 2.0 ± 0.2; HS, 1.9 ± 0.3 liter/min), and similar renal inulin clearances (RL, 48 ± 16; HS, 44 ± 7 ml/min). The net fluid gain (resuscitation fluid volume infused minus urine output as percentage of body weight) was much greater in the RL group (7.2 ± 1.0%) than in the HS group (0.48 ± 0.2%). Plasma volume (PV, percentage of body weight) was measured with Evans blue dye in these splenectomized dogs. The increase in PV in the RL dogs (1.25 ± 0.04%) was slightly greater than the increase in the HS group (0.94 ± 0.13). Prenodal skin lymph was collected from both hindpaws, and the fractional increase in skin lymph flow after RL (4.5 ± 2.9) was greater than the increase in the HS group (1.7 ± 0.3). A small volume of HS can resuscitate dogs in endotoxin shock as well as an equal sodium load of RL by expanding the plasma volume with fluid that shifts to the intravascular compartment.