Hemodynamic effects of lactic acid infusion in healthy piglets

Introduction Lactic acidosis is considered detrimental for cardiovascular system. Ex vivo, it may alter the function of myocardial fibers [1] and whole heart [2]. In vivo, its association with cardiovascular impairment is less well defined [3,4]. Aim To evaluate the effects of lactic acidosis on hemodynamics of healthy piglets. Methods Ten sedated and mechanically ventilated healthy piglets were infused with lactic acid (30% solution) to induce severe lactic acidosis (lactic acid group, n=5) or with normal saline (control group, n=5), for ten hours. Arterial pH and lactate, heart rate (HR), mean arterial pressure (MAP), stroke volume (SV) and cardiac output (CO) were recorded over time. Results Compared to saline, lactic acid infusion increased arterial lactate (18±5 vs. 1±0 mmol/l, p<0.001) and decreased arterial pH (6.90± 0.10 vs.7.51±0.08, p<0.001). None of the variables of interest significantly differed between the two groups at the beginning (data not shown) and at the end (see Table) of the study. All animals survived until the end of the study. [Control Group (n=5) Lactic acid Group (n=5) probability ]HR (bpm) 101 ± 17 84 ± 12 0.10 MAP (mmHg) 82 ± 17 109 ± 27 0.09 SV (ml) 23 ± 4 27 ± 7 0.35 CO (l/min) 2.4 ± 0.8 2.3 ± 0.8 0.84 Table. Data are expressed as mean ± standard deviation; p reflects the result of t-test. Conclusions These results show that lactic acidosis, per se, does not cause major hemodynamic impairment and is well tolerated by healthy animals.