Acid-base pathophysiology after 130 years: confusing, irrational and controversial.

BACKGROUND: The interface between acid-base physiology and blood gas interpretation is historically both stimulating and turbulent. Since the pioneering work of many celebrated names in the history of acid-base disorders, such as Arrhenius, Henderson, Hasselbalch and many more to follow, substantial progress in acid-base knowledge has been made over the last 130 years. Out of the chaos of competing definitions, concepts and terms, many have tried to bring an orderly approach to acid-base balance. Nevertheless, the mechanisms responsible for acid-base balance are unfortunately still incompletely understood, and moreover, considerable controversy has developed over the past decade as to how to classify and understand acid-base derangements occurring as a result of abnormalities in acid-base balance.
METHODS: Analysis of the medical literature, including a MEDLINE and EMBASE search, and a search of internal medicine, critical care and nephrology textbooks and reference lists, was performed on topics pertaining to the assessment and management of acid-base disorders, focusing on the gaps in our knowledge and on controversial issues.
RESULTS: Several confusing, irrational and controversial issues concerning acid-base nomenclature, reference values, pathophysiology, assessment of acid-base disorders and therapy were found.
CONCLUSIONS: Despite huge progress in acid-base knowledge, several confusing, irrational and controversial issues remain. Suggestions to reduce the confusion are provided.