A patient with salicylic acid poisoning has the following aerial blood gas analysis repo : pH = 7.12 : pCO2 = 18mmHg; HCO3 = 12mmol/L. The resulting acid base abnormality can be best labeled as:
Answer is A (Metabolic acidosis with compensatory respiratory alkalosis): With pH < 7.35 (7.12) acidosis is confirmed. Abbnormal CO2 with change in opposite to expected. (acidosis should have increased CO2) indicates that the change in compensatory (compensatory respiratory alkalosis), Decreased bicarbonates with change in keeping with change in pH suggests that the problem is metabolic. Thus the whole picture respresents metabolic acidosis with compensatory respiratory alkalosis. Explanation : Acid base disorders needlessly, confuse many people, but if a few simple rules are applied then interpretation and diagnosis are easy. pH < 7.35 is acidosis ; pH > 7.45 is alkalosis If change in HCO3 is termed as metabolic If change in HCO3- is in keeping with the pH (i.e. if there is acidosis and HCO3- decreased) the problem is a Metabolic one. If change in HCO3 is opposite with the pH (if there is acidosis and HCO3 is increased or normal) the problem is compensatory metabolic. If change is CO2 is termed as respiratory If change in CO2 is in keeping with the pH (if in acidosis CO2 is raised) the problem is termed respiratory If change in CO2 is opposite with the pH (if there is acidosis and CO2 is decreased or normal) problem is termed as compensatory respiratory. STEP III : Final deduction Because metabolic component is primary and respiratory component is compensatory the acid base disorder is Metabolic acidosis with compensatory Respiratory alkalosis.
Metabolic acidosis with compensatory respiratory alkalosis
Metabolic acidosis with compensatory respiratory alkalosis
Respiratory acidosis with metabolic alkalosis
Metabolic acidosis