The evolution of therapy for dehydration: should deficit therapy still be taught?

OBJECTIVE: To describe the evolution of rehydration therapy for cholera and diarrheal dehydration from its beginning in 1832 to the present. To reaffirm the central role for extracellular fluid (ECF) expansion and question the continued teaching of deficit therapy in many current pediatric texts.

METHODOLOGY: I reviewed the rationale underlying three treatment strategies: rapid parenteral infusions of saline solutions to restore ECF; deficit therapy to replace specific electrolyte and water losses; and oral rehydration therapy (ORT) to effect both. I used crude mortality rates as the measure of outcomes.

RESULTS: (1) Beginning in 1832 for cholera and 1918 for infant diarrheal dehydration, parenteral saline infusions were infused to replace losses of salt and water; they were very effective in salvaging moribund dehydrated patients by quickly restoring ECF volume and renal perfusion. Mortality rates dropped from more than 60% to less than 30%. (2) Deficit therapy as it evolved in the 1950s defined potassium and other fluid and electrolyte deficits and replaced them using specific but complicated fluid and electrolyte replacement regimens. Mortality rates dropped to single digits. (3) ORT, with intravenous expansion of ECF volume when indicated, rapidly corrected specific fluid and electrolyte disorders with a very simple therapeutic regimen. Mortality rates dropped to less than 1%.

CONCLUSIONS: The simpler, more effective ORT regimen should be taught as standard therapy for diarrheal dehydration. Principles of body fluid physiology should be taught in their own right.