This application performs comprehensive oxygenation and acid-base calculations. We believe that it is unique in that it can interpret acid-base problems using either PCO2-pH, PCO2- Base excess or PCO2-Strong Ion Differences. The reasoning underlying each type of interpretation is explained so that it can also be used as a teaching tool. The acid-base tab consists of three pages. The first page, directly accessed via the Acid Base tab, allows specification of any two values for pH, PCO2 or HCO3 and solves for the third value, corrected for temperature, if specified in either Celsius or Fahrenheit. It also calculates the pH and HCO3 expected for an acute or chronic pure respiratory change and the pH and PCO2 expected for a pure metabolic change. The acid base analysis page, assessable from the Acid-Base page, permits the user to change default electrolyte concentrations specified in either mmol/L, mEq/L or mg/dl. Default albumin and lactate concentrations may also be adjusted. Using these values and the pH, PCO2 and PCO2 from the preceding page, the application calculates the uncorrected and corrected anion gaps, with or without using potassium concentration, the anion gap ratio, the base excess, the strong ion difference, the effective strong ion difference and the strong ion gap. These values are incorporated into the three types of interpretations, shown on the next page.
The oxygen tab allows calculation of arterial and venous PO2, saturation (SO2) and Oxygen Content (CO2) from any one of these three values, with temperature, hemoglobin, PCO2 and pH corrections. The Alveolar PO2 (PAO2), PAO2:FiO2 ratio and Alveolar-Arterial Oxygen Partial Pressure Difference (AaDO2) are calculated from user-entered values for FiO2, Barometric Pressure and the Respiratory Quotient. The venous, arterial and estimated alveolar blood contents are used to calculate venous admixture (Qva/Qt).
Help is available adjacent to all calculations. An extensive hyper-linked help is also available as a separate page