[The therapy of hypovolemic shock in cows with right-sided abomasal displacement]

In this trial, the effect of supplementary administration of the opioid antagonist Naloxone was tested, in comparison to infusion of Ringer's-solution only, in the treatment of hypovolemic shock in cows suffering from right-sided abomasal displacement. Twenty cows were selected by several criteria (pulse rate greater than 95/min; plasma chloride content less than 90 mmol/l; body temperature less than 39.5 degrees C) and alternatively assigned to the Naloxone group and the control group. All animals were treated surgically by the usual clinical method. After opening the abdominal cavity paralumbally from the right, intravenous administration of 13 l of Ringer's-solution was started and continued for about 5 hours. In addition, the cows of the experimental group received 0.75 g Naloxone as an intravenous bolus before, and 1 g Naloxone dissolved in 7 l fluid during the first hour of the permanent drip infusion. Further treatments (additional fluid therapy or administration of purgatives and ruminomotorics on the following days) were given according to the condition of the animal. The evaluation of efficacy was done in regard to the clinical (course of disease), and clinicochemical (e.g. hemogram, blood gas analysis, plasma chloride, plasma lactate) parameters as well as to blood pressure. No statistically significant differences were found between both groups. Only nine of the twenty cows were sent home cured, one patient of each group died one day after surgery, and the remaining 9 animals had to be sent to the slaughterhouse within 3 to 22 days after surgery after only transient improvement. These results suggest, that under the conditions described, conventional fluid therapy is equivalent to fluid therapy with addition of Naloxone. Hypoxic damage of the abomasum caused by its displacement and the subsequent hypovolemic shock are discussed as main causes for the poor postsurgical prognosis of right-sided abomasal displacement.