Howorth P J
Br J Dis Chest. 1975 Apr;69(2):75-102.
Acid-base terminology including the sue of SI units is reviewed. The historical reasons why nomograms have been particularly used in acid-base work are discussed. The theoretical basis of the Henderson-Hasselbalch equation is considered. It is emphasized that the solubility of CO2 in plasma and the apparent first dissociation constant of carbonic acid are not chemical constants when applied to media of uncertain and varying composition such as blood plasma. The use of the Henderson-Hasselbalch equation in making hypothermia corrections for PCO2 is discussed. The Astrup system for the in vitro determination of blood gases and derived parameters is described and the theoretical weakness of the base excess concept stressed. A more clinically-oriented approach to the assessment of acid-base problems is presented. Measurement of blood [H+] and PCO2 are considered to be primary data which should be recorded on a chart with in vivo CO2-titration lines (see below). Clinical information and results of other laboratory investigations such as plasma bicarbonate, PO2,P50 are then to be considered together with the primary data. In order to interpret this combined information it is essential to take into account the known ventilatory response to metabolic acidosis and alkalosis, and the renal response to respiratory acidosis and alkalosis. The use is recommended of a chart showing the whole-body CO2-titration points obtained when patients with different initial levels of non-respiratory [H+] are ventilated. A number of examples are given of the use of this [H+] and PCO2 in vivo chart in the interpretation of acid-base data. The aetiology, prognosis and treatment of metabolic alkalosis is briefly reviewed. Treatment with intravenous acid is recommended for established cases. Attention is drawn to the possibility of iatrogenic production of metabolic alkalosis. Caution is expressed over the use of intravenous alkali in all but the severest cases of metabolic acidosis. The role of 2,3-diphosphoglycerate on tissue oxygenation is stressed and use of intravenous sodium phosphate as an alternative to intravenous bicarbonate is mentioned.
回顾了包括国际单位制使用在内的酸碱术语。讨论了在酸碱工作中特别使用列线图的历史原因。考虑了亨德森 - 哈塞尔巴尔赫方程的理论基础。强调当应用于诸如血浆等成分不确定且变化的介质时，二氧化碳在血浆中的溶解度和碳酸的表观一级解离常数并非化学常数。讨论了亨德森 - 哈塞尔巴尔赫方程在对体温过低时的PCO₂进行校正中的应用。描述了用于体外测定血气和衍生参数的阿斯特鲁普系统，并强调了碱剩余概念的理论弱点。提出了一种更以临床为导向的评估酸碱问题的方法。血液[H⁺]和PCO₂的测量被视为应记录在带有体内二氧化碳滴定线的图表上的主要数据（见下文）。然后应将临床信息和其他实验室检查结果，如血浆碳酸氢盐、PO₂、P50与主要数据一起考虑。为了解释这些综合信息，必须考虑已知的对代谢性酸中毒和碱中毒的通气反应，以及对呼吸性酸中毒和碱中毒的肾脏反应。建议使用一张图表，该图表显示不同初始非呼吸性[H⁺]水平的患者通气时获得的全身二氧化碳滴定点。给出了一些使用该体内[H⁺]和PCO₂图表解释酸碱数据的例子。简要回顾了代谢性碱中毒的病因、预后和治疗。对于确诊病例，建议静脉输注酸进行治疗。提请注意医源性代谢性碱中毒的可能性。除了最严重的代谢性酸中毒病例外，对静脉使用碱表示谨慎。强调了2,3 - 二磷酸甘油酸对组织氧合的作用，并提及使用静脉注射磷酸钠作为静脉注射碳酸氢盐的替代方法。
