FLUID & ELECTROLYTES 1 INTERNAL MEDICINE.pdf

INTERNAL MEDICINE

1. Fluids and Electrolytes
(Part 1: Fluids)
Janice F. Bacani-Carandang, MD, DPPS

2. Composition of Body Fluids
nTotal Body Water
nFluid Compartments
nElectrolytes

3. WATER
nthe most plentiful constituent of the human
body
nTotal body water (TBW) as a percentage of
body weight varies with age
nAt birth: 75% of birthweight
n1st yrof life: TBW ↓to 60% until puberty

4. WATER
nWhat happens during puberty?
nFat content in females increases
nMales acquire more muscle mass
nSince fat has very low water content, TBW in
males remains at 60% while TBW in females
decrease to 50%.
nAlso, during dehydration: TBW is ↓

5. FLUID COMPARTMENTS
nTBW is divided into 2 main compartments:
nExtra-cellular fluid (ECF)
nPlasma water-5%
nInterstitial fluid-15%
nIntra-cellular fluid (ICF)

6. FLUID COMPARTMENTS
nFetus and newborn: ECF > ICF
post-natal diuresis: ↓ ECF
continued expansion of ICF (cellular growth)
nBy 1 year of age: ECF: ICF ratio approaches
adult levels
nECF:20-25% of body weight
nICF:30-40% of body weight

7. FLUID COMPARTMENTS
nPlasma water-5%
nAltered by dehydration, anemia,
polycythemia, heart failure,
hypoalbuminemia

8. FLUID COMPARTMENTS
nInterstitial fluid-15%
nIncreases dramatically in diseases
associated with edema
nHeart failure, protein-losing
enteropathy, liver failure, nephrotic
syndrome and sepsis

9. FLUID COMPARTMENTS
nHydrostatic and oncotic forces
nDepends on the limited permeability of
albumin across the capillaries
nOver-all, there is a net movement of fluids
out of the intravascular space to the
interstitial space.
nThis fluid is returned to the circulation via
the lymphatics.

10. FLUID COMPARTMENTS
nOsmotic Equilibrium
maintains ECF and ICF balance because
the cell membrane is permeable to water.
n285-295 mOsm/kg
nCan also be measured by calculating glucose
and blood urea nitrogen (BUN)

11. Dehydration and Fluid
Management

12. Definition of DEHYDRATION
nExcessivelossofwaterfromthebodyor
fromanorganorabody part, as occurs
during illness or fluiddeprivation.
nTheprocessofremovingwaterfroma
substanceora compound.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company.

13. Dehydration
nfrequently the result of DIARRHEA
na common problem in children
ncontinues to be a serious problem in many
areas of the world
nEspecially lethal when superimposed on
malnutrition

14. Approach to Dehydration
nFIRST STEP:
Assess Degree of Dehydration
↓
dictates both the urgency of the
situation AND the volume of fluid
needed for rehydration
↓
either 1. Minimal/ None;
2. Moderate or
3. Severe

15. Symptoms Associated with Dehydration
SYMPTOM MINIMAL/ NONE
(<3% of Body Weight)
MILD –MODERATE
(3-9% of Body Weight)
SEVERE
(>9% of Body Weight)
Mental Status Well, alert Normal, fatigued or
restless, irritable
Apathetic, lethargic,
unconscious
Thirst Drinks normally; might
refuse liquids
Thirsty, eager to drinkDrinks poorly; unable
to drink
Heart Rate Normal Normal to increasedTachycardia
Quality of pulsesNormal Normal to decreasedWeak, thready or
impalpable
Breathing Normal Normal; fast Deep
Eyes Normal Slightly sunken Deeply sunken
Tears Present Decreased Absent
Mouth and
Tongue
Moist Dry Parched
Skin fold Instant recoil Recoil in <2 sec Recoil in >2 sec
Capillary refillNormal Prolonged Prolonged; minimal
Extremities Warm Cool Cold, mottled, cyanotic
Urine output Normal to decreasedDecreased Minimal

16. Clinical Evaluation of Dehydration
MILD
(3-5%)
MODERATE
(7-10%)
SEVERE
(10-15%)
Normal/ increased
pulse
Tachycardia Rapid and weak pulse,
decreased BP
Decreased urine outputLittle or no urine outputNo urine output
Thirsty
Normal PE Irritable, lethargic
Sunken eyes & fontanelVery sunken eyes & fontanel
Decreased tears No tears
Dry mucous membranes Parched mucous membranes
Mild tenting of the skinTenting of the skin
Delayed capillary refillVery delayed capillary refill
Cool and pale skin Cold and mottled skin

17. REMEMBER!
nClinical assessment of dehydration is
only an estimate and based on range
nThe patient must be continually re-
evaluated during therapy (hydration
rounds)
nPE findings are usually proportional to
the degree of dehydration (refer to table of
symptoms shown earlier)

18. Approach to Dehydration
nSECOND STEP:
Treat dehydration accordingly
(depends on the degree of dehydration where
you classified your patient)

19. NO DEHYDRATION
nRehydration therapy is NOT applicable
(because patient is NOT dehydrated, no need to rehydrate)
nOngoing losses should be continually replaced
with Oral Rehydration Solution (ORS)
WHO Recommendations:
Sodium: 75 mEq/L Chloride: 65 mEq/L
Glucose: 75 mEq/L Potassium: 20 mEq/L
Citrate: 10 mEq/L
nEmphasize 3 F’s to the watcher:
Fluids, Food, Follow-up

20. NO DEHYDRATION
nHow to replace ongoing losses?
If patient weighs:
<10 kg:60-120 ml ORS for each diarrheal stool
or vomiting episode
>10 kg:120-240 ml ORS for each diarrheal
stool or vomiting episode
* If stool volume can’t be measured, 10-15
ml/kg/hrORS is appropriate

21. 2 yr/Male; 12 kg
WITH NO DEHYDRATION
nRehydrate or not? NO
nReplace ongoing losses? YES
nHow?
>10 kg:120-240 ml ORS for each
diarrheal stool or vomiting
episode

22. MILD DEHYDRATION
nRehydrate with ORS 50 ml/kgbody weight
over 3-4 hrs
nReplace ongoing losses:
If patient weighs:
<10 kg:60-120 ml ORS for each diarrheal stool
or vomiting episode
>10 kg:120-240 ml ORS for each diarrheal
stool or vomiting episode
* If stool volume can’t be measured, 10-15
ml/kg/hrORS is appropriate

23. 2 yr/Male; 12 kg
WITH MILD DEHYDRATION
nRehydrate or not? YES
nHow?
50 ml X 12 kg= 600 mlin 3-4 hrsOR
150-200 ml/hr
nReplace ongoing losses? YES
nHow?
>10 kg:120-240 ml ORS for each
diarrheal stool or vomiting
episode

24. MODERATE DEHYDRATION
nRehydrate with ORS 100 ml/kgbody weight
over 3-4 hrs
nReplace ongoing losses the same way as in
NO or MILD Dehydration
* ORS therapy is less expensive than IV therapy
and has a lower complication rate

25. 2 yr/Male; 12 kg
WITH MODERATE DEHYDRATION
nRehydrate or not? YES
nHow?
100 ml X 12 kg= 1,200 mlin 3-4 hrsOR
300-400 ml/hr
nReplace ongoing losses? YES
nHow?
>10 kg:120-240 ml ORS for each
diarrheal stool or vomiting
episode

26. Emphasize NUTRITION while treating
Dehydration:
nContinue breastfeeding
nResume age-appropriate normal diet after
initial hydration, including adequate caloric
intake for maintenance
nVomiting may occur during the first 2 hrsof
giving ORS→ lessens over time

27. Limitations to Giving ORS
1.Shock
2.Ileus
3.Intussusception
4.Carbohydrate intolerance
5.Severe emesis
6.High stool output (> 10 ml/kg/hr)

28. Risk Factors Necessitating IV
Resuscitation (instead of oral route):
1.Age < 6 months
2.Prematurity
3.Chronic illness
4.Fever > 38C if < 3 mos, or > 39C if 3-36 mos
5.Bloody diarrhea
6.Persistent emesis
7.Poor urine output
8.Sunken eyes
9.Depressed level of consciousness

29. SEVERE DEHYDRATION
nIntravenous (IV) therapy is required
immediately and oral therapy is not even
considered.
nIn addition, IVF is required in those:
1. with uncontrollable vomiting;
2. those unable to drink because of
extreme fatigue, stupor, or coma; or
3. those with gastric or intestinal
distention

30. FLUID MANAGEMENT OF
SEVERE DEHYDRATION
1. Restore intravascular
volume
Normal saline or Lactated Ringer’s solution:
20 mL/kg over 20 min
(Repeat until intravascular volume is restored)
2.Rapid volume
repletion
Normal saline or Lactated Ringer’s solution:
20 mL/kg over 2 hours
3. Calculate 24-hr water
needs
nCalculate maintenance water
nCalculate deficit water
4. Calculate 24-hr
electrolyte needs
nCalculate maintenance sodium and potassium
nCalculate deficit sodium and potassium
5. Select an appropriate
fluid
Administer half the calculated fluid during the first
8 hrs, first subtracting any boluses from this
amount
Administer the remainder over the next 16 hrs

31. MAINTENANCE WATER
nBody Weight Method:
0-10 kg:100 ml/kg
11-20 kg:1000 ml + 50 ml/kg for each
kg > 10 kg
> 20 kg:1500 ml + 20 ml/kg for each
kg > 20 kg

32. DEFICIT WATER
Percent dehydration ×weight
Mild: 3-5 %
Moderate: 7-10%
Severe: 10-15%
nAny value may be used, either the lower
or higher, as long as it is within the
given range.

33. Laboratory Exams to Request:
nSerum electrolytes (Na, K, Ca, Mg, Cl)
nBUN and Serum creatinine
nUrinalysis (specific gravity)
nCBC (Hemoconcetration)

34. 2 yr/Male; 12 kg
WITH SEVERE DEHYDRATION
1. Restore intravascular
volume (20 mL/kg)
20 ml X 12 kg= 240 ml over 20 mins
2. Rapid volume
repletion (20 mL/kg)
20 ml X 12 kg= 240 ml over 2 hours
3. Calculate 24-hr water
needs
(Maintenance + Deficit)
Maintenance: 1000 ml + 50(2 kg)= 1,100 ml
Deficit: 15% X 12 kg= 1,800 ml
TOTAL: 2,900 ml
4.Calculate 24-hr
electrolyte needs
5. Select an appropriate
fluid
(Give half in 8 hrs, less
the bolus given; then
give remaining in 16 hrs
2,900 ml divided by 2= 1,450 ml
1,450 ml-480 ml= 970 ml in 8 hrs(121.5
ml/hr)
The remaining 1,450 ml will be given in 16 hrs
(90 ml/hr)
may use 10-15%

35. CORNERSTONES OF
MANAGEMENT
nOral Rehydration Solution
nContinued feeding
nZinc (recommended by WHO and UNICEF)
< 6 mos: 10 mg/ day for 14 days
> 6 mos: 20 mg/ day for 14 days

36. MONITORING THERAPY
nVital signs
Pulse, Blood pressure
nIntake and output
Fluid balance, Urine output & specific gravity
nPhysical Examination
Weight, clinical signs of depletion or overload
nElectrolytes

37. STUDY HARD!
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