Pharmacology - IV fluid therapy Flashcards
- Fluid compartments and review using the “Four questions” approach
- Different fluid types, their properties and clinical indication
- Sensible and Insensible losses
- The 5 R’s of Fluid loss – including resuscitation, routine maintenance, replacement and repletion of electrolytes.
Total body water is made of three distinct compartments, that contain different elemental and fluid properties
Given the heterogenous nature of people, assessment of fluid balance is vital
Different fluids have different properties, and have their own place within treatment
Understanding the four step approach can guide you to the correct choice and type of fluids
Osmolarity v tonicity
+ what is the main determinant of tonicity
Solute concentration per unit VOLUME of solvent
Concentration of solutes dissolved in solution which influence the osmotic pressure gradient (i.e. the impermeable solutes)
-tonicity mainly determined by Na+
What are the fluid compartments (2)
total body water is 60% of body mass
2/3 ICF
1/3 ECF - 20% plasma (i.e. intravascular), 80% interstitial fluid
What component of blood doesn’t contain any RBCs or WBCs
Plasma
Normal blood osmolality (number of osmoles of solute/KG)
Normal plasma osmolarity (number of osmoles of solute/litre)
290 mOsm/kg (290-300)
298 mOsm/L (290-300)
What is the 4 question approach to whether a patient needs IV fluids
What is my patients volume status?
Does my patient NEED IV Fluids?
How much fluid do they need?
-add up losses in last 24hrs and GIVE THIS VOLUME BACK
What type of fluid do they need?
Examples of colloid fluid (mostly stay in intravascular space, i.e. plasma in ECF)
Gelatins Starches Dextrans Albumin Blood products
Examples of crystalloid fluid (mostly stay in intracellular space)
5% dextrose 0.9% saline Hartmann’s solution Plasma-lyte "Normal saline” in 4% dextrose (0.18% saline/4% dextrose)
Symptoms of hypovolaemic patient (4)
Signs of hypovolaemic patient (4)
Nausea
Thirsty
Dizzy
Dry mouth
Flat veins
Dark urine
Oliguria + reduced frequency
Low BP, High HR
Treatment/ what type of maintenance fluid (i.e. resuscitation, routine maintenance, replacement) does a hypovolaemic patient need
Resuscitation fluids (if low BP) Rehydration fluids
Symptoms of hypervolaemic patient (2)
Signs of hypervolaemic patient (4)
Dyspnoea
Sweaty
Distended veins
Peripheral oedema (potentially ascites or pulmonary oedema)
High BP
Dilute urine
Treatment of hypervolaemic patient
Limit water/salt intake
Diuretics (if pulmonary oedema)
Dialysis or haemofiltration (if anuric)
Before administering fluid, work out their water deficit by looking at losses in what potential ways (think sensible and insensible)
Sensible
- Urine - 1600ml lost a day
- Faeces - 100ml lost a day
- Vomit
- Sputum
Insensible
- Skin - 400ml lost a day
- Lungs - 400ml lost a day
- Sweat - 100ml lost a day
- Open wounds
- Burns
- Bleeding
The 5 R’s of fluid
Resuscitation Routine maintenance Replacement Redistribution Reassessment
Why are resuscitation fluids used
Used urgently to restore circulation with hypovolaemia
