Haemodynamic and renal effects of resuscitation of dogs from haemorrhagic shock with hypertonic saline or Lactated Ringer's solution combined with whole blood

Despite numerous studies on haemorrhagic shock treatment, the choice of fluid and the rate of administration is a subject of controversy. Early haemodynamic effects, neuroendocrine response and renal function following acute sodium load with either hypertonic saline (HS) or Lactated Ringer's (LRS) were investigated in a model of controlled haemorrhagic shock. Six anaesthetized dogs were bled 30% of calculated blood volume, i.e., 27 ml/kg b.w. over 15 min and left untreated for 30 min. Afterward, the dogs were treated with either HS 4 ml/kg b.w. or LRS 81 ml/kg b.w., followed by whole blood. After a resting period of at least 30 days, the dogs underwent a similar second shock experiment, but with the second solution. Haemodynamics, renal effects and neuroendocrine response were studied during shock and at 15, 30, 45 and 60 min after administration of HS or LRS and 30 and 60 min after the addition of whole blood. LRS treatment resulted in significantly higher cardiac filling pressures and cardiac performance indexes than HS but, following whole blood administration, there were no differences between treatments, except that pulmonary capillary wedge pressure was higher in the LRS group. Urinary output and glomerular filtration rate index were restored to normal values by both treatments; however, they were significantly higher in the LRS group until whole blood was administered. LRS and HS restored plasma norepinephrine to baseline values with no difference between the treatments. Both solutions improved haemodynamics and renal function but their effects were short lived and whole blood was required for a favourable outcome, regardless of the initial solution used. In contrast to LRS, HS did not overload the cardiovascular system.