Effect of infusion of hypertonic saline solution on conscious heifers with hypoxemia caused by endotoxin infusion

Abstract

Objective - To compare effects of IV infusion of a small volume (5 ml/kg of body weight) of hypertonic saline (7.2% NaCl) solution (HSS) and IV infusion of an equivalent volume of isotonic saline (0.9% NaCl) solution (ISS) on arterial blood gases in conscious heifers with hypoxemia caused by endotoxin infusion. Animals - 9 Holstein heifers. Procedure - All heifers received 2.0 μg of endotoxin/kg, IV, during a 5-minute period. Twenty-five minutes after endotoxin infusion, 3 heifers received ISS, 3 received HSS, and the remaining 3 did not receive fluids (control). Heifers were monitored for 150 minutes after initiation of fluid replacement. Arterial blood gases, blood pressure, and serum electrolyte concentrations were measured. Results - Endotoxin administration had a profound effect on pulmonary function, causing severe hypoxemia accompanied by a significant decrease in the partial pressure of oxygen (PaO2) and a significant increase in the arterial-alveolar O2 gradient (P[A-a]O2). Cattle in the HSS group had progressive and significant increases in PaO2 and O2 saturation, compared with the other groups. The P(A-a)O2 values for the control and ISS groups were slightly decreased until 150 minutes after initiation of fluid replacement; however, HSS infusion induced a progressive and significant decrease in P(A-a)O2 for the remainder of the experimental period. Conclusions and Clinical Relevance - Rapid infusion of HSS can successfully resuscitate conscious cattle with induced pulmonary dysfunction. Infusion of HSS may be beneficial for initial resuscitation of cattle with naturally developing bovine respiratory disease complex.