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Fluid & Electrolytes

Presenters:Dr. Nur-Athirah Binti Md.NorDr. Siti Nor Afni Binti Baharum

Supervisor:Dr. Lo

20 January 2014

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Outline

1. Fluid1. Physiology2. Type of IV fluid3. IV Fluid therapy4. IV cannula and rate

2. Electrolytes : causes, clinical features and management

1. Potassium2. Sodium 3. Calcium

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Physiology• 60% of body weight is consist of fluid (42L)• 2/3 of total body fluid is in Intracellular fluid• 1/3 of total body fluid is in Extracellular fluid– 80% is interstitial fluid– 20% is plasma (3L)

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Important Ionic Concentrations (mmol/L)

ICF ECF

NaK CaMgCl

PO4

HCO3

101502.57.5104510

1354

2.51

1001

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Daily input and output of water

• Body received fluid by – Ingestion and metabolism (total 2.3L)

• Body remove fluid by– Insensible loss (lung & skin), sweat, feces and

urine (total 2.3L)• Fluid requirement less in CKD and CCF• Fluid requirement more in fever, vomiting,

burn, diarrhea

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Fluid in Surgical Practice

• Fluid balance tend to disturb when pt– Nil orally– Trauma– Sepsis

• In a surgical patient, we must know to calculate – volume and electrolyte requirement– volume and electrolyte excess and deficit

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Crystalloid

ISOTONIC• 0.9% NaCl• Hartmann solutionHYPERTONIC• 10% Dextrose, 20 % Dextrose, 50% Dextrose• 3% Saline, 5% SalineHYPOTONIC• 5% Dextrose• 0.45% Saline

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The most common crystalloid solutionsTypes of isotonic

Composition Notes

NaCl 0.9% NaCl

150 mmol/L150 mmol/L

Use to correct ECF loss and for initial resuscitation of intravascular volume.

Ringer’s Lactate (Haartman)

NaKCaClHCO3

131 mmol/L5mmol/L2mmol/L111mmol/L29mmol/L

It is physiological solution. After administration the lactate is metabolised, resulting in bicarbonate generation. It will decrease the risk of hyperchloraemia

Dextrose 5% dextrose 50g/L200kcal/L

Glucose is rapidly metabolized. The remaining water distributes rapidly throughout the body’s fluid compartments therefore not suitable for resuscitation.

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Colloids

• Colloid solutions contain particles that have oncotic pressure– Natural : Albumin– Synthetic : Gelatins, Hydroxyethyl starches,

Dextrans • It remains largely within the intravascular

space • Half-life is 6 to 24 hours.

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Crystalloid vs. ColloidCrystalloids Colloids

Advantage • Cheap• Accessible

• Longer half life • Smaller volume required to expand intravascular volume

Disadvantage • Short half life• Larger volume required for resuscitation

•Expensive• Risk of allergic reaction

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Assessment and monitoring

Indicators : – Hypotension– Tachycardia – Capillary refill >2s– Urine output <0.5 ml/kg/h

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Resuscitation

• Initial resuscitation– Give high flow O2– 2 large bore IV access– Identify cause of deficit and response

• Bolus of 20ml/kg in adult or 10ml/kg in pt with CKD or CCF

• Burn = TBSA(%) x 4 x body weight (kg)

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Maintenance

• 30-35ml/kg/24h in adult• Paediatrics and Burn– 1st 10kg 100ml/kg– Next 10kg 50ml/kg– Subsequent weight 20ml/kg• Eg: 25kg boy (100x10)+(50x10)+(20x5) • = 1600 ml / 24hours

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Replacement and Redistribution

• On going losses– NG tube, Drains, Fistula, Third space losses

• Concentration is similar to plasma• Can be replace with isotonic fluids

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Complication of over hydration

• Fluid overload• Signs– Weight gain– Pulmonary edema– Peripheral edema– S3 gallop

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IV Cannula and fluid flow rates

• Flow rate is limited by the size of the IV cannula and viscosity of fluid

Cannula size Colour Time to infuse 1000ml Normal saline under ideal circumstances

22 G Blue 22 min

20 G Pink 15 min

18 G Green 10 min

16 G Grey 6 min

14 G Red 3.5 min

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Hyperkalaemia

Causes: ↓ excretion – renal failure↑ load – K sparing diuretic, blood

transfusion Clinical features: Arrhythmias, paralysis Management:

Lytic cocktail Oral Kalimate Dialysis

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Hyponatraemia Causes:

Hypovolaemia – renal failure, diuretics, vomiting, pancreatitis, SBO

Euvolaemia – SIADHHypervolaemia – CCF, liver failure

Clinical features: Na < 120 mmol/L – disturbed mental statusNa < 110 mmol/L – seizure, coma

Management: Treat the u/l causesReplace the lossesNot > 10mmol/L/day - central pontine myelinolysis

[Na req = Na deficit + Na maintenance] & [Na def = 135 – pt’s level x 0.6 x BW]

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Hypernatraemia

Causes: ↑ intake – salt ingestion, hypertonic saline ↑ loss – vomiting, diarrhea, fistula

Clinical features : Irritability, confused, comaManagement:

Allow fluid as tolerated IVD D5%

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Hypocalcaemia

Causes: Surgical – Acute pancreatitisMedical – Vit D def

Clinical features: Cramp, tetany, Chvostek’s sign, Trousseau’s sign

Management: –Iv calcium gluconate–Calcium oral supplement–Vitamin D supplement

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Hypercalcaemia

Causes: Surgical – malignancies, bones metastasisMedical – myeloma, Addison’s disease

Clinical features: ‘Bones, stones, groans, moans’Management:

Rehydration and saline diuresisIv Pamidronate

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Take home messages

1. Crystalloid and colloid are equally effective for the correction of hypovolaemia

2. Use isotonic fluid for fluid resuscitation to maintain wall of cell membrane

3. High volume administration of normal saline produces hyperchloremic acidosis

4. Use at least 16G cannula for fluid resuscitation5. Hypokalaemia & hyperkalaemia need to be treated with caution

– might lead to arrhythmias 6. Na replacement should not > 10 mmol/L/day – risk of central

pontine myelinolysis7. Main treatment for hypercalcaemia is saline diuresis

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Sources

• Textbook of Medical Physiology by Guyton and Hall, 11th Edition

• Principles of Anatomy and Physiology by G.Tortora and B.Derrickson, 12th edition

• Principles and Practice of Surgery by O.J.Garden, A.W.Bradbury, J.L.R. Forsythe and R.W. Parks, 6th edition

• Sarawak Handbook of Medical Emergencies, 3rd Edition