• Dehydration occurs when body fluid (water) loss exceeds fluid intake
  • Most common fluid and electrolyte disorder in the elderly
  • Associated with high mortality rate yet often under recognized, untreated or inadequately prevented
  • Is part of the normal dying process, except when sudden death occurs, and in dying can enhance somnolence which can be beneficial by reducing anxiety




When a resident is known to be terminally ill and becomes moribund and possibly dehydrated, a work-up is not necessarily appropriate. Hydration, if not already addressed, should be discussed with the patient or Health Care Agent and their wishes, in accordance with any Advanced Care Directives, followed. If a “Comfort Care” plan has not been established and documented the discussion needs to take place immediately. A basic hydration laboratory panel must be obtained while awaiting discussion and/or decisions. If no Advanced Directives exist the patient and/or responsible party should still be given the opportunity to discuss the plan of care and to provide a written affidavit stating their wishes for the treatment of dehydration.


If the resident is not considered to be terminally ill but is dehydrated or at risk for dehydration a more comprehensive work-up is likely appropriate. If Advanced Directives exist prohibiting parenteral hydration it is not necessary to continue monitoring laboratory values once the diagnosis is established and the agent’s ongoing wishes reaffirmed and documented. At this point every effort should be made to offer oral intake as safely as possible.



  • Increased fluid loss: fever, diarrhea, vomiting, excessive diaphoresis, diuretics, laxatives, increased activity, tachypnea, hot weather, gastrointestinal bleed
  • Decreased fluid intake: nausea, cognitive impairment, dysphagia, fluid restricted diets, inadequate fluid offerings
  • Conditions contributing to dehydration or fluid imbalances: DM, DI, SIADH, recent surgery, HF, age-related physiologic changes in kidneys, adipsia




  • Suspicion of increased output and/or decreased intake
  • ≥ 2 signs or symptoms:  weight loss, dry mucosa, cognitive change, fever, vomiting, postural hypotension, oliguria, dizziness, lethargy, weakness, falls, anorexia, dysphagia
  • BUN/creatinine ratio >25:1, or orthostasis (drop in SBP ≥20mm/HG or AP change of 10-20 BPM >baseline with change of position), or AP >100BPM






  • Following CONTEXT//COMMUNICATION guidelines laboratory tests should establish diagnosis of dehydration [BMP]
  • Identify type of dehydration as follows:


Hypertonic dehydration

Water loss > salt loss

Excess diuretics, infection, fever, diabetes insipidus

Hypotonic dehydration

Water loss < salt loss

Diuretics or salt-wasting renal disease

Isotonic dehydration

Water & salt loss equal

Diuretics, severe diarrhea or vomiting

Excess water retention or intake

Inappropriate water retention

SIADH or increased fluid intake

Excess water & salt retention

Inappropriate water & salt retention

CHF, liver failure



  • Physical examination should establish degree of effect on patient and possible causes or contributing factors
  • Review of all diagnosis and medications, dietary records, bowel records, nursing documentation may establish likely causes




  • Following CONTEXT//COMMUNICATION guidelines if no work-up and/or treatment is to be offered documentation of this decision should be recorded in the MD/NP progress note. The “Comfort Care” plan should also be documented.
  • Choice of treatments influenced by factors contributing to dehydration, risks and potential complications of rehydration, patient or health care agent preferences, availability of treatment.
  • Treat conditions causing dehydration – HF, infections, diarrhea, etc.
  • Eliminate offending medications where possible – diuretics, antibiotics, ACEIs, etc.
  • If fluids are to be replaced select the route of administration: choices [oral, intravenous, nasogastric, hypodermoclysis] based on availability, wishes of patient or health care agent, degree of dehydration.


Replace fluid loss - ½ in first 24 hours and the rest in next 48-72 hours using formula:


Estimated fluid deficit =

[serum sodium x (total body weight {kg} x 0.5)] - (total body weight {kg} x 0.5)




  • Options for monitoring rehydration include dietary intake records, weight, repeated laboratory evaluation, and/or physical and cognitive assessment. Monitoring should be continued until patient returns to baseline or decision is made by patient or health care agent to discontinue aggressive rehydration plan of care. Document such decisions.
References for Dehydration: 


1.      AMDA, Dehydration and Fluid Maintenance Clinical Practice Guideline, 2001.

2.   Fordyce, M.: Dehydration Near the End of Life in Annals of Long-Term Care, Vol.8, No. 5, May 2000, 29-33.