ABSTRACT
Arterial blood gas analysis provides valuable information about acid-base balance and respiratory and metabolic function. Blood pH lesser than 7.35 is acidotic, while pH greater than 7.45 is alkalotic. Blood gas samples should not be taken within 20 minutes of any changes to ventilation, or any interventions that affect respiratory function. Blood acid–base balance is the sum of: respiratory and metabolic. Chemical buffers respond rapidly, within seconds, balancing hydrogen ions by binding acids to bases. Chemical buffers are produced in many places, but especially in the liver, therefore hepatic failure causes metabolic acidosis. Bicarbonate is essentially an extracellular chemical, so increasing serum bicarbonate will not counter intracellular acidosis. High carbon dioxide tension therefore indicates respiratory acidosis, while low carbon dioxide tension indicates respiratory alkalosis. Blood gas analysis remains one of the most valuable means of monitoring respiratory and metabolic function.
