Unformatted text preview: PRINCIPLES OF FLUID &
ELECTROLYTE BALANCE IN
SURGICAL NORMAL DAILY LOSSES AND
REQUIREMENTS FOR FLUIDS AND
ELECROLYTES Volume Na+ K+
ML mmol mmol
Urine 2000 80 60
Insensible losses 700
Faeces 300 10
Minus endogenous 300
Water Total 2700 80 70 ASSESSING LOSSES IN THE
SURGICAL INSENSIBLE FLUID LOSSES EFFECT OF SURGERY
The stress response ‘ThirdSpace’ losses
Loss from the gastrointestinal tract INTRAVENOUS FLUID
INTRAVENOUS 5% DEXTROSE
RINGER’S LACTATE (HARTMANN’S SOLUTION)
HAEMACCEL (SUCCINYLATED GELATIN)
GELOFUSINE (POLYGELINE GELATIN)
HUMAN ALBUMIN SOLUTION 4.5% (HAS;PPF) PROVISION OF NORMAL 24-HR FLUID &
ELECTROLYTE REQUIREMENTS BY
Intravenous fluid Additive Duration 500 ml 0.9% NaCl 20mmol KCl 500 ml 5% Dextrose 500 ml 5% Dextrose 500 ml 0.9%Dextrose 500 ml 5% Dextrose 20 mmol KCl 500 ml 5% Dextrose 4hr 4hr
4hr 20 mmol KCl
4hr AETIOLOGY OF HYPER AND HYPONATRAEMIA
nausea and vomiting
reduced conscious level
Increased loss *Sweating (pyrexia,hot environment) *respiratory tract loss(increased ventilation, administration of dry gases) *administration of dry gases *burns
Inappropriate urinary water loss
Diabetes inspidus(pituitary •
Excessive Sodium load (hypertonic fluid, parenteral nutrition) Hyponatraemia
Low extracellular fluid volume * Volume depletion (vomiting,diahrrhoea,burns,decreas
ed fluid intake) * salt losing renal disease * Hypoadrenalism *diuretic use Normal extracelluler fluid volume hypothyroidism SIADH Increased extracellular fluid volume excessive water •
excessive mannitol use
• CONSEQUENCES OF HYPER
Arrythmias(broadcomplex rhythms,bradycardia,heart block,ventricular fibrillation)
Muscle heart block
Muscle weakness MANAGEMENT OF SEVERE ACUTE
HYPERKALAEMIA (K+ > 7mmol/L)
HYPERKALAEMIA Identify and treat cause
10 – 20 mL intravenous 10% calcium chloride over 10 min in patients with ECG abnormalities (reduced risk of ventricular fibrillation)
50 mL 50%dextrose plus 10 units short acting insulin over 23min Monitor plasma glucose and K+ over next3060 min)
Regular Salbutomol nebulizers
Consider oral or rectal calcium
Resonium (ion exchange resin),although this is more effective for nonacute hyperkalaemia.
Haemodialysis for persistent hyperkalemia ACID BASE BALANCE
ACID METABOLIC ACIDOSIS
MIXED PATTERN OF ACIDBASE IMBALANCE COMMON CAUSES OF METABOLIC
ACIDOSIS IN THE SURGICAL
PATIENT LACTIC ACIDOSIS
Shock (any causes)
ACCUMULATION OF OTHER ACIDS
Acute Renal Failure
INCREASED BICARBONATE LOSS
Ureterosigmoidostomy COMMON CAUSES OF METABOLIC
LOSS OF SODIUM AND WATER Vomiting
Aspiration of gastric secretions
Diuretic administration HYPOKALEMIA CAUSES OF RESPIRATORY
ACIDOSIS Excessive opiate administration Pulmonary complications e.g Pneumonia CAUSES OF RESPIRATORY
ALKALOSIS ENCOUNTERED IN
SURGICAL Hyperventilation during mechanical ventilation
Central nervous system disorders(meningitis,encephalopathy)
Septicaemia Principles of fluid and
electrolyte balance in
What are the normal values or serum sodium, potassium, creatinine and urea?
What are the normal basal requirements for water, sodium and potassium?
How can this be provided in a patient who is fasting?
How is fluid retained in the intravascular compartment?
What might cause it to leak out? 6.
In clinical practice, it is often desirable to "expand" the intravascular compartment. Why might this be desirable and how could it be done?
What are the clinical symptoms and signs of fluid depletion? How can the severity of fluid depletion be assessed?
How can clinicians assess the patient’s response to resuscitation in severe fluid depletion? 9.
What biochemical disturbance might you expect in a patient with gastric outlet obstruction who has been vomiting for several days before admission?
10. What biochemical abnormalities might you expect in a patient who has had excessive diarrhoea and who has been drinking large amounts of water because of thirst? (If a house officer inadvertently prescribed too much 5% dextrose and not enough N Saline, you would find the same effect)
In patients with massive burns, fluid losses are impossible to measure. How might you assess fluid requirements? ...
View Full Document
- Fall '11
- Hypokalemia, alkalosis, Acid-base homeostasis, Acid-base disturbances, Davenport diagram