[Procedural analysis of acid-base balance disorder: case serials in 4 patents].

OBJECTIVE: To establish the standardization process of acid-base balance analysis, analyze cases of acid-base balance disorder with the aid of acid-base balance coordinate graph.

METHODS: The acid-base balance theory were reviewed systematically on recent research progress, and the important concepts, definitions, formulas, parameters, regularity and inference in the analysis of acid-base balance were studied. The analysis of acid-base balance disordered processes and steps were figured. The application of acid-base balance coordinate graph in the cases was introduced.

RESULTS: The method of "four parameters-four steps" analysis was put forward to analyze the acid-base balance disorders completely. "Four parameters" included pH, arterial partial pressure of carbon dioxide (PaCO2 ), HCO3 - and anion gap (AG). "Four steps" were outlined by following aspects: (1) according to the pH, PaCO2 and HCO3 - , the primary or main types of acid-base balance disorder was determined; (2) primary or main types of acid-base disorder were used to choose the appropriate compensation formula and to determine the presence of double mixed acid-base balance disorder; (3) the primary acid-base balance disorders were divided into two parts: respiratory acidosis or respiratory alkalosis, at the same time, the potential HCO3 - should be calculated, the measured HCO3 - should be replaced with potential HCO3 - , to determine whether there were three mixed acid-base disorders; (4) based on the above analysis the data judged as the simple AG increased-metabolic acidosis was needed to be further analyzed. The ratio of ΔAG↑/ΔHCO3 - ↓ was also needed to be calculated, to determine whether there was normal AG metabolic acidosis or metabolic alkalosis. In the clinical practice, PaCO2 (as the abscissa) and HCO3 - (as the ordinate) were used to establish a rectangular coordinate system, through origin (0, 0) and coordinate point (40, 24) could be a straight line, and all points on the straight line pH were equal to 7.40. The acid-base balance coordinate graph could be divided into seven areas by three straight lines [namely pH = 7.40 isoline, PaCO2 = 40 mmHg (1 mmHg = 0.133 kPa) line and HCO3 - = 24 mmol/L line]: main respiratory alkalosis area, main metabolic alkalosis area, respiratory + metabolic alkalosis area, main respiratory acidosis area, main metabolic acidosis area, respiratory + metabolic acidosis area and normal area. It was easier to determine the type of acid-base balance disorders by identifying the location of the (PaCO2 , HCO3 - ) or (PaCO2 , potential HCO3 - ) point on the acid-base balance coordinate graph.

CONCLUSIONS: "Four parameters-four steps" method is systematic and comprehensive. At the same time, by using the acid-base balance coordinate graph, it is simpler to estimate the types of acid-base balance disorders. It is worthy of popularizing and generalizing.