Shirer H W, Erichsen D F, Orr J A
Department of Physiology and Cell Biology, University of Kansas, Lawrence 66045.
J Appl Physiol (1985). 1988 Aug;65(2):534-40. doi: 10.1152/jappl.1988.65.2.534.
Previous reports indicate that intravenous infusion of HCl can alter breathing and blood pressure even if reductions in systemic arterial pH are prevented. To extend these findings, as well as to determine whether other acids elicit comparable results, this report compares the cardiopulmonary response between right atrial infusion of lactic acid and HCl in awake ponies. Lactic acid, infused at a dose of 1.5 mmol/kg over 18 min, lowered systemic and pulmonary arterial pH 0.062 and 0.092 U, respectively, and increased pulmonary arterial pressure (delta Ppa, 4 mmHg), heart rate (HR, 4/min), and tidal volume (delta VT, 190 ml/m2). HCl, infused at a reduced dose of 0.5 mmol/kg over 18 min, lowered systemic and pulmonary arterial pH 0.024 and 0.047 U, respectively, but produced increases in Ppa (delta 23 mmHg), HR (delta 42/min), and VT (delta 321 ml/m2) that were significantly greater than from the larger dose of lactic acid. These results indicate that cardiopulmonary responses to infusion acidosis differ between the type of acid infused. It is suggested that, in the unanesthetized pony, HCl-induced infusion acidosis has a unique cardiopulmonary-stimulating action unrelated to the pH changes imparted to the circulating arterial blood and that this response is absent during the infusion of lactic acid.
先前的报告表明，即使能防止全身动脉pH值降低，静脉输注HCl仍可改变呼吸和血压。为了扩展这些发现，并确定其他酸是否会产生类似结果，本报告比较了清醒小马右心房输注乳酸和HCl时的心肺反应。以1.5 mmol/kg的剂量在18分钟内输注乳酸，分别使全身和肺动脉pH值降低0.062和0.092 U，并使肺动脉压（ΔPpa，4 mmHg）、心率（HR，4次/分钟）和潮气量（ΔVT，190 ml/m²）增加。以0.5 mmol/kg的降低剂量在18分钟内输注HCl，分别使全身和肺动脉pH值降低0.024和0.047 U，但使Ppa（Δ23 mmHg）、HR（Δ42次/分钟）和VT（Δ321 ml/m²）的增加显著大于较大剂量的乳酸。这些结果表明，输注不同类型的酸引起的心肺反应不同。提示在未麻醉的小马中，HCl诱导的输注性酸中毒具有独特的心肺刺激作用，与循环动脉血的pH变化无关，而在输注乳酸期间不存在这种反应。
