Experimental protocol for metabolic acidosis induction by intravenous administration of hydrochloric acid in sheep

ABSTRACT The aim of this study was to assess the magnitude and duration of blood and urine changes and the side effects of hyperchloremic acidosis induced by the intravenous administration of hydrochloric acid in sheep. Five healthy, crossbred adult ewes, with a mean body weight of 44±2.9kg were used. The hydrochloric acid solution was administered intravenously at a rate of 25mL/kg/h for 4 hours continuously. Venous blood and urine samples were collected and pH values, blood carbon dioxide partial pressure, bicarbonate, base excess, strong ion difference, anion gap, total concentration of nonvolatile buffers, creatinine, plasma L-lactate, plasma and urine sodium, potassium, and chloride were determined. The experimental protocol induced severe hyperchloremic acidosis at the end of the infusion, with a decreased plasma strong ion difference. The fractional excretion of sodium and chloride remained increased during 4 hours after the infusion. Aciduria was observed at approximately 24 hours. Twenty-four hours after the infusion, the animals showed mild and compensated metabolic acidosis. This protocol was effective in inducing severe and long-lasting hyperchloremic acidosis and did not cause serious side effects. Therefore, this protocol can be used safely in adult sheep for studies on the treatment of this condition.

摘要 本研究旨在评估绵羊经静脉输注盐酸（hydrochloric acid）诱导的高氯性酸中毒（hyperchloremic acidosis）时，血液与尿液指标变化的幅度、持续时间及该操作的副作用。本实验选用5只健康成年杂交母羊（crossbred adult ewes），平均体重为44±2.9kg。以25mL/kg/h的速率持续静脉输注盐酸溶液，时长共4小时。采集静脉血（venous blood）与尿液样本，检测指标包括pH值、血二氧化碳分压（blood carbon dioxide partial pressure）、碳酸氢盐（bicarbonate）、碱剩余（base excess）、强离子差（strong ion difference）、阴离子间隙（anion gap）、非挥发性缓冲总浓度（total concentration of nonvolatile buffers）、肌酐（creatinine）、血浆L-乳酸（plasma L-lactate），以及血浆与尿液中的钠、钾、氯含量。实验方案在输注结束时诱导出严重高氯性酸中毒，同时伴随血浆强离子差降低。输注结束后的4小时内，钠与氯的排泄分数（fractional excretion of sodium and chloride）仍维持升高状态。约24小时时观察到酸尿症（aciduria）。输注后24小时，受试动物呈现轻度代偿性代谢性酸中毒（metabolic acidosis）。本方案可有效诱导严重且持续时间较长的高氯性酸中毒，且未引发严重副作用，因此可安全应用于成年绵羊的该疾病治疗相关研究。