principals of fluids and electrolytes management
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Principals of fluids and electrolytes management. Ram Elazary , MD General Surgery Department Hadassah Hebrew University Medical Center Campus Ein-Kerem , Jerusalem. Total Body Water. body weight%Total body water% Total 60100 I ntracellular 4067 E xtracellular 2033 - PowerPoint PPT PresentationTRANSCRIPT
Principals of fluids and electrolytes management
Ram Elazary, MDGeneral Surgery Department
Hadassah Hebrew University Medical CenterCampus Ein-Kerem, Jerusalem
Total Body Waterbody weight% Total body
water%
Total 60 100Intracellular 40 67Extracellular 20 33Intravascuar 5 8Interstitial 15 25
Composition of Fluidsplasma interstitial intracellular
CationsNa 140 146 12K 4 4 150Ca 5 3 10Mg 2 1 7AnionsCl 103 104 3HCO 24 27 10SO4 1 1 -HPO4 2 2 116Protein 16 5 40
Control of VolumeKidneys maintain constant volume and composition of body fluids
– Filtration and reabsorption of Na
– Regulation of water excretion in response to ADH
Water is freely diffusible– Movement of certain ions and proteins
between compartments restricted
Control of VolumeEffective circulating volume
– Portion of ECF that perfuses organs
– Usually equates to Intravascular volume
Third space loss– Abnormal shift of fluid for Intravascular
to tissues eg bowel obst, i/o, pancreatitis
Normal Water ExchangeMean daily (ml) Minimal daily (ml)
SensibleUrine800-1500 600Intestinal up to litersSweat up to liters 500
InsensibleLungs/Skin 600-900 600-900( 10%/1 o rise in Temp)
Normal source of water
~2000ml - 1300 free water intake
700 bound to food
additional water from catabolism
Water and Eletrolytes ExchangeSurgical patients prone to disruption:
• NPO• anaesthesia• Trauma (surgery)• sepsis
Fluid and Electrolytes Therapy
Surgical patients need: •Maintenance volume requirements•On going losses•Volume excess/deficits•Maintenance electrolyte requirements•Electrolyte excess/deficits
1 .Volume Deficit • vital signs changes
– Blood pressure– Heart rate– CVP
• Peripheral temperature and capillary filling time
• urine output low
1 .Volume Deficit •Decreased skin turgor•Sunken eyes•Oliguria•Orthostatic hypotension•High BUN/Creatine ratio•Plasma Na may be normal
Fluids resusitation
• Adults:1000 ml
• Pediatrics:20 ml/kg
Fluids of crystaloids (NS or RL)Repeated dose
2. Maintenance RequirementsThis includes: insensible loss
urinarystool losses
Body weight Fluid required0-10Kg 100ml/kg/dnext 10-20Kg 50 ml/kg/dsubsequent Kg 20ml/kg/d
15ml/Kg/d for elderly
70 Kg Man Needs
1st 10kg x 100mls = 1000mls
2nd 10kg x 50mls = 500mls
Next 50kg x 20mls= 1000mls
TOTAL 2500 mls /d
Maintenance Electrolyte Requirements
Na 1-2mEq/Kg/d K 0.5 - 1
mEq/Kg/d• Usually no K given until urine output is adequate• Always give K with care, in an infusion slowly - never bolus
(max 0.2% KCL through peripheral IV)
• Na 1gr = 17 mEq• K 1gr = 13.6 mEq
• 70 KgH2O 2500ml Na 70*2 =140 mEq = ~ 9grK 70*1 =70 mEq = ~ 5gr
2500 0.45NS + 0.2%KCl 100ml/h
fluids composition
3 .On Going Losses• NGT
• drains
• fistulae
• third space losses
4 .Volume Excess• Over hydration• Mobilization of third space losses
Signs• weight gain• pulmonary edema• peripheral edema• S3 gallop
Fluid and Electrolyte Therapy
Goals• normal hemodynamic parameters• normal electrolyte concentration
Method replace deficits
normal maintenance requirementsongoing losses
Fluid and Electrolyte Therapy
Normal maintenance requirements• use BW formula
On going losses• measure all losses in I/O chart• estimate third space losses
Deficits• estimate using vital signs• estimate using U/O
Fluid and Electrolyte Therapy
The best estimate of the volume required is the patients response
After therapy started observe • vital signs• Urine output (0.5mls/Kg/hr)• Central venous pressure
Time Frame for Replacement
• Usually correct over 24 hours
• For ill patients calculate over shorter period and reassess e.g. 1, 2 hours or 3 hours for e op cases
• Deficits - correct half the amount over the period and reassess
Postoperative Fluid Therapy
• Check IV regimen ordered in op form
• Assess for deficits by checking I/O chart and vital signs
• Maintenance requirements calculated
• Usually K not started
• Monitor carefully vital signs and urine output
Postoperative Fluid Therapy• Urine specific gravity may be used (1.010 -
1.012)
• CVP useful in difficult situations (5-15 cm H20)
• Body weight measured in special situation e.g. burns
Concentration Changes• changes in plasma Na are indicative of
abnormal TBW
• losses in surgery are usually isotonic
• hypoosmolar condition usually caused by replacement with free water