Effects of FiO2 on O2 consumption and cardiovascular and hormonal responses to hemorrhage in the goat.
This study was conducted to determine whether 100% FiO2 during hemorrhage would improve maintenance of mean arterial blood pressure and to assess the cardiovascular, arginine vasopressin, and renin-angiotensin system roles in the response. This also allowed evaluation of FiO2 effects on the baroreceptor control of these hormone systems. Six conscious female goats were hemorrhaged (0.5 mL x kg(-1) x min(-1)) for 30 minutes, while breathing 11%, 21%, or 100% O2. Mean arterial blood pressure was maintained only when the goats breathed 100% O2. FiO2 did not affect O2 consumption or delivery during hemorrhage. Increases in renin and arginine vasopressin were equal or reduced with 100% FiO2 and therefore did not contribute to the improved mean arterial blood pressure maintenance. Inspiration of 100% FiO2 during hemorrhage, therefore, may improve perfusion pressure with no changes in O2 consumption or delivery. Also, 100% FiO2 eliminated the negative correlation between both hormones and right atrial pressure, suggesting altered baroreceptor control of the hormones.
Claybaugh
John R
JR
Department of Clinical Investigation, Tripler Army Medical Center, Tripler AMC, HI 96859-5000, USA.
Sato
Aileen K
AK
VanScoy
Steven C
SC
D000818:Animals; D001794:Blood Pressure; D005260:Female; D006041:Goats; D006339:Heart Rate; D006439:Hemodynamics; D006470:Hemorrhage / Q000503:physiopathology*; D010101:Oxygen Consumption; D011311:Pressoreceptors / Q000502:physiology; D011897:Random Allocation; D012084:Renin-Angiotensin System / Q000502:physiology; D013318:Stroke Volume