Veterinarni Medicina, 56, 2011 (4): 187–201 Original Paper 187 Haemodynamic and renal effects of resuscitation of dogs from haemorrhagic shock with hypertonic saline or Lactated Ringer’s solution combined with whole blood A. Seliskar 1 , A. Nemec Svete 1 , M. Kozelj 2 1 Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia 2 University Medical Centre Ljubljana, Ljubljana, Slovenia ABSTRACT: 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 func- tion 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 haemody- namics 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. Keywords: haemorrhagic shock; fluid therapy; dog; haemodynamics; renal function; norepinephrine Haemorrhagic shock is a clinical syndrome mani- fested by reduced perfusion of vital organs lead- ing to inadequate delivery of oxygen and nutrients necessary for normal tissue and cellular function (Krausz, 2006). Haemorrhagic shock occurs when a patient loses 30% or more of its estimated blood volume. Venous return to the heart decreases and this in turn causes decreased cardiac output and activation of a variety of homeostatic mechanisms including hormonal modulation and cardiovascular neurologic reflexes. Compensatory mechanisms help improve blood volume, sustain the blood pres- sure, and maintain perfusion to the vital organs such as heart, brain and kidney. Perfusion can be maintained for a short period of time following mild to moderate volume loss, however, without intervention, compensatory mechanisms eventu- ally fail and the complications of shock ensue. The goal of treatment is to improve tissue perfusion and oxygenation, and the mainstay of the treatment for haemorrhagic shock is the expansion of the in- travascular volume by intravenous fluid therapy (Mandell and King, 1998). Currently, isotonic crystalloids such as Lactated Ringer’s are recommended to be used as the initial resuscitation fuid in the treatment of haemorrhagic shock. No more than one-ffth of unexcreted isotonic crystalloids remain within the plasma volume after Supported by the Slovenian Ministry of Higher Education, Science and Technology (Programme Group P4-0053).