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Cardiorespiratory responses to HCl vs. lactic acid infusion
H W Shirer1, D F Erichsen, J A Orr
1Department of Physiology and Cell Biology, University of Kansas, Lawrence 66045.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 1, 1988
Summary
Infusing hydrochloric acid (HCl) into ponies caused greater cardiopulmonary stimulation than lactic acid, even at lower doses. This suggests HCl has a unique effect on cardiovascular and respiratory systems unrelated to blood pH changes.
Area of Science:
- Cardiopulmonary Physiology
- Acid-Base Balance
Background:
- Intravenous acid infusion can affect breathing and blood pressure.
- Previous studies noted these effects even when preventing systemic arterial pH reduction.
Purpose of the Study:
- To compare cardiopulmonary responses to right atrial infusion of lactic acid versus hydrochloric acid (HCl) in awake ponies.
- To determine if different acids elicit comparable cardiopulmonary results.
Main Methods:
- Awake ponies underwent right atrial infusion of either lactic acid (1.5 mmol/kg) or HCl (0.5 mmol/kg) over 18 minutes.
- Systemic and pulmonary arterial pH, pulmonary arterial pressure (Ppa), heart rate (HR), and tidal volume (VT) were measured.
Main Results:
- Lactic acid infusion lowered pH and moderately increased Ppa, HR, and VT.
- HCl infusion, at a lower dose, caused significantly greater increases in Ppa, HR, and VT compared to lactic acid.
- Both acids lowered systemic and pulmonary arterial pH, but the effects on cardiovascular and respiratory parameters differed significantly.
Conclusions:
- Cardiopulmonary responses to infusion acidosis vary depending on the type of acid used.
- Hydrochloric acid (HCl) exhibits a unique cardiopulmonary-stimulating action in ponies, independent of systemic pH changes.
- This specific HCl-induced response appears absent during lactic acid infusion.