RESUMEN
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.