Intravenous Fluids Flashcards
What is diffusion?
Movement of solute from high conc to low through semi-permeable membrane
What is osmosis?
Movement of water from high to low conc through a solute-impermeable membrane
What is osmolarity?
Solute conc per unit volume of solvent
What is osmolality?
Measure of solute conc per unit mass of solvent
What is Tonicity?
Measure of the osmotic pressure gdt between two solutions
In what proportions is water stored in the body?
2/3 intracellular
1/3 extracellular (20% intravascular)
How is fluid balanced assessed?
ABCDE Capillary refill ECG Skin turgor Patient weight Pulse contraanalysis Input/output
What are the 4 uses of fluids?
Resuscitation Routine maintenance Replacement Redistribution (reassessment)
What is the limit for maintenance fluids?
MAX 100mls/hr
What are the types of fluid?
Crystalloid
Colloid
What are some crystalloid fluids?
Salines
Dextrose
What are some Colloid fluids?
Blood
Albumin
Starch
How does hypovolaemia present?
Nauseous Thirsty Flat veins Cool peripheries No sweat Low/postural BP High heart rate Concentrated oliguria
How is a hypovolaemic patient managed?
Resuscitation fluids if low BP
Rehydration fluids
Find the cause
How does hypervolaemia present?
Breathless, not thristy Distended veins Warm, oedematous extremities Sweaty High BP/HR Dilute urine
How is a hypervolaemic patient managed?
Diuretics
Haemofiltration (if anuric)
What can cause difficulty in treating patients with fluid imbalance?
Low oncotic pressure
Heart failure
Low protein can cause oedema in dehydrated patients how?
Loss of intracapillary fluid whilst behaving hypovolemic
What are the questions to be asked in prescribing fluids?
What is the patient’s volume status?
Does the patient NEED IV fluids?
How much fluid is needed?
What types of fluid do they need?
What must be taken into consideration when working out how much fluid a patient needs?
Work out water deficit Catheters/drains Input charts Vomit bowls/sputum pots Stool charts
What is the normal daily loss of water in adults?
400-800mls
What conditions can affect how much fluid a patient needs?
Sepsis Ventilation Open wounds Burns Bleeding
What are the benefits of Dextrose fluids?
Moves through all compartments
Chronic dehydration
Hypernatremia
What are the risks of dextrose fluids?
Not useful for blood volume expansion
Isotonic
Not useful in resus, low albumin
When are crystalloids used?
Acute dehydration
AKI
Resuscitation
When are crystalloids not used?
Long term maintenance Hypernatremic patient (High sodium load)
Dextrose fluids enter what fluid compartment?
Total body water
Crystalloid fluids enter what fluid compartment?
Remain in ECF
Plasma expander fluids enter what fluid compartment?
IVS (as colloid)
When are plasma expanders used?
Liver patients
Inter-operative
