The Use and Abuse of Bicarbonate in Neonatal Acid-Base Derangements

Abstract

Acid-base homeostasis in the human being is controlled by buffer systems and compensatory mechanisms. The most important clinical buffer system is the bi- carbonate system. The six major acid-base derangements-metabolic acidosis, respiratory acidosis, combined acidosis, metabolic alkalosis, respiratory alkalosis, and combined alkalosis-can be explained in terms of the bicarbonate buffer system and their occurrence secondary to specific pathophysiologic processes. Treatment of acid-base derangements in the past has been empirical, especially with regard to the usage of sodium bicarbonate. This approach has led to some serious complications. When the physiologic mechanisms of acid-base homeostasis are examined, logical processes for treatment become apparent. These are: 1) iden- tify the primary acid-base abnormality with complete blood gas data and accurate interpretation; 2) identify compensating mechanisms and assess the extent and source of compensation; 3) correct the primary abnormality by identifying and treating the cause of the derangement, and 4) if rapid correction of the problem cannot be accomplished, then enhancement of compensatory mechanisms or buffering may be necessary.