Cardiac Output and Acid-Base Balance During Acute Hemorrhagic Shock

Cardiac output and arteria-venous pH, Peo2 was determined after acute hemorrhage from a jugular vein. the amount 10. 20 and 30% of estimated total blood volume of dogs. The bleeding period lasted approximately one hour on each 10% of blood loss. Cardiac output was measured analyzing the saline dilution curve drawn on physiograph, the extra-arte rial conductivity. using Stewart-Hamilton formula. 1. After blood loss of 10. 20 and 30% of total blood volume. cardiac output decreased from 103C±5) ml/min/kg of normal to 98(±7). 8IC±8) and 66C± 11) ml/min/kg. respectively. Decrement of cardiac output were consistant and significant after more than 20% of blood loss. Stroke volume changed from 7.3C±0.49) ml to 6. 5C±0. 58). 4.5(±0.61J and 4.4 C±0.461ml. respectively. The decrease of stroke volume appeared relatively earlier than the decrease of blood pressure and cardiac output in successive bleeding. this would be associated with the decreased venous return. 2. During the above succeeding acute blood loss. arterial blood pressure were decreased significantly from 153(±7) mmHg to 138 、±8). 107(±9) and 71(±6) mmHg. indicating more marked pressure drop can be produced after each successive blood 105s. 3. Total peripheral resistance changed from O. 131 (±0.012) mmHg/ml/min to o. 132(±0. 019). 0.110 <±0.020) and 0.100(±0. 014) mmHg/mI/min. respectively. It appears. therefore. that pressure drop after more than 30% of blood loss is not only due to the decrement of cardiac output but decrement of peripheral resistance. 5. Acid-Base balance during the acute hemorrhagic shock was primarily metabolic origin. arterial blood pH changed from 7.42 to 7.43. 7.35 and 7.38. venous blood pH changed from 7. 38 to 7.36. 7.26 and 7.20. respectively. The pH changed markedly and significantly after more than 20% of blood loss. with negligible change of arterial and venous PCOI • Plasma potassium ion concentration increased as the increase of blood loss from 3.0(±0.14) mEq/L to 3.4(± 0.20). 4. 3(±O. 43) and 3. 9(±0. 29) mEq/L