<prompt> Arterial blood gas analysis of a patient reveals-pH 7.2, HCO3 36 mmolL pCO2 60 mm of Hg. The abnormality is -Respiratory acidosis with metabolic alkalosisRespiratory acidosisRespiratory alkalosis withRespiratory acidosis with metabolic acidosis  <response>: In this patientpH decreased acidosis N 7.4HCO3- Increased N 24 mm Hg 2PCO2 Increased N 40 Hg 2 First stepDetermine whether it is acidosis or alkalosisDecreased pH 7.2 suggests acidosis.Second stepobserve HCO3-PCO2 to determine the cause of acidosis or alkalosisPCO2 is increased which indicates respiratory acidosis.HCO3- is increased which indicates metabolic alkalosisThe abnormality which is in sync with the change in pH is increased pCO2 i.e., increased pCO2 is responsible for decreased pH or acidosis So the primary abnormality in this case is respiratory acidosis.Third stepThis step requires determining whether the patients compensation is appropriate Change in PCO2 20 mm Hg. N 40, observed 60Expected change in HCO3- 2 mmolL for 20 mm Hg change in PCO2For every 10 mm increase in PCO2, HCO3- increases to 1 mmolLSo the expected value of HCO3- 26 mmolLBut the observed value of HCO3- 36 mmolLThis suggests that some other abnormality other than respiratory acidosis exists which has increased the HCO3- value to more than expected.A disorder which increases the HCO3- concentration is metabolic alkalosisThus this is a case of mixed disorder, where respiratory acidosis and metabolic alkalosis exist together. 