Frank Tenney MD

Deficit Therapy

Rapid Repair

Oral Rehydration

References

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part two

Definitions
  • Diarrheal Dehydration
·         Contraction of ECF volume

o        Loss of plasma volume

o        Loss of Interstitial fluid
·         Substantial loss of intracellular potassium
·         No intracellular dehydration

·         Next

 

 

 

 

 

Body Fluids -- A Review
 
  • Total Body Water is 55% - 72% of body mass
·         Varies with sex, age, and fat content
·         Distributed between intracellular and extracellular spaces
  • Extracellular Fluid (ECF)
·         One third of total body water (TBW)
·         Intravascular plasma fluid
  • Na, Cl, HCO3 [K, Mg, Ca, PO4, SO4, organic acid, protein]
·         Extravascular interstitial fluid
  • Na, Cl, HCO3 [similar but less protein]
  • Intracellular Fluid (ICF)
  • K, proteins, Mg, SO4, PO4
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link to table

 

The Concept of 'Deficit'(2)
   
1832 -- Parenteral saline infusions first used  for cholera Mortality decreased from >60% to <30%
 1918 -- intraperitoneal saline infusions for infant diarrheal dehydration 9 of 9 infants survived
 1923 -- Gamble identified the importance of maintaining ECF volume and composition to well-being  Mortality decreased from >80% to <25%
 1946 -- Darrow equated deficits of Na, K, Cl and H2O with retentions measured during recovery "Deficit therapy" defines the requirements for restoring body composition to normal

Calculating a deficit therapy regimen and prescribing specific solutions to replace the deficits were complicated

 
 1953 -- Talbot attempted to simplify therapy by combining goals of replacement therapy and maintenance therapy  This failed because NaCl was low and K of Butler's solution was high; this prevented a rate of infusion sufficient to restore ECF volume and renal perfusion   IV Table
 1956 -- ICF was found not to change in diarrheal dehydration (except in hyperosmolar states)  K losses are accounted for by cell catabolism and reduced cell K concentration
 Diarrheal dehydration is recognized as loss of ECF but not ICF The case for rapid restoration of ECF volume followed promptly by maintenance therapy containing K was strengthened
Hyponatremia was commonly seen There was a low concentration of Na in replacement fluids
Hypernatremia became commonplace Oral solutions contained too much salt and/or too much sugar
Deficit therapy model used to guide repair of hypo / hyper-natremia These calculations added complexity to the deficit therapy regimen
1973 -- Oral Replacement Therapy (ORT) successful in infant diarrheal dehydration Simple and effective.  90% recovered without IV therapy.
Hirschhorn recommends rapid ECF restoration (usually with ORT) and early feeding. Mortality fell to <3 / 1000
Infant diarrhea in the US is associated with mild dehydration and responds to simple ORT US still has 200 000 hospitalizations and 400 deaths / yr  (2 per 1000 admissions)
   
   
 

link to table
 

link to Solutions Table

 

 

 

 

 

 

Recommendations (3)
 
Most diarrhea leads to mild - to - moderate dehydration deficit table ORT, using simple ORT solutions, followed quickly by prompt refeeding solutions table

Children with mild - to - moderate dehydration can be treated at home by aggressive ORT without intravenous infusions
 
Severe dehydration  

Evaluate electrolytes to monitor for severe hypo / hyper - natremia or acidosis

 Reserve deficit therapy for the extremes of these conditions

20 - 60 mL/kg Ringer's lactate solution given IV over 15- to 60-min period

 Restore circulation, ECF volume, renal perfusion

Follow IV repair by ORT and early feedings -- begin within 6 hrs

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