Interpreting Blood Gas Analysis

Blood gas analysis is one of the most frequently performed investigations in ICU. It informs the clinicians about gas exchange, acid-base status, and often also about blood concentrations of electrolytes, glucose, and lactate. Interpretation of acid-base status is often based on pattern recognition (e.g. lactate 5 mM and base excess −5 mM = lactic acidosis). In ICU patients, combined acid-base disorders are common and therefore, more detailed analysis is needed to decipher the disorder. There are many approaches to acid-base analysis, but here we describe a simplified base-excess partitioning method.