Abstract
Hemorrhage stimulates the secretion or cateoholamines by newborns and adults. This study directly compares the response of newborn and adult sheep to hemorrhage after alpha-blockade. We chronically instrumented 11 newborn lambs, and 8 adult sheep for continuous measurement of blood pressure (BP), heart rate (HR), and thermodilution cardiac output (CO). After pretreatraent with prazosin (P), an alpha-1 blocker, or vehicle (V) in a randomized, crossover fashion, each animal was hemorrhaged 20% of its blood volume. Cardiac output was measured at baseline; 20 mins after drug administration; after hemorrhage; at 100 mins, after which the animal was retransfused; and at 150 mins. Stroke volume (SV) and total peripheral resistance (TPR) were calculated. The effects of treatment with P and V on the measurements are shown in the table. All deviations from baseline were significant (p<.05). There were greater decreases in BP, CO, SV and TPR in P-treated versus V-treated ewes (indicated by *, p<.05). This difference was not seen in the lambs. (NC denotes no change.)
We conclude that catecholamines do not play a major part in the response to hemorrhage in the lamb. (Supported by NIH Grant HD 17644.)
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Block, S., Rose, J. & Lorentz, W. 240 HEMODYNAMIC RESPONSES OF LAMBS AND ADULT SHEEP TO HEMORRHAGE. Pediatr Res 19, 150 (1985). https://doi.org/10.1203/00006450-198504000-00270
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DOI: https://doi.org/10.1203/00006450-198504000-00270