Osmoles definition

Measure of the number of osmotically active particles in solution

Molarity defitnition

Number of moles of a substance in a solution

Water Distribution (in health)

Roughly a rule of 1/3rds…

- 2/3rds of total body mass in water

- 1/3rd of this is in the extra-cellular compartment

- 1/3rd of this is in the intra-vascular compartment

Standard formula for IV fluids regime

• 4ml/kg/hr for the 1st 10kg
• 2ml/kg/hr for the 2nd 10kg
• 1ml/kg/hr for every kg after that

Loss in fever (sweat)

Water

NaCl

Loss in DM (Urine)

Glucose, water, KCl, NaCl, phosphate

Loss in vomitting (gastric content)

HCl and water, KCl

Loss in diarrhoea (faeces)

water, KCl, NaCl

Loss in Burns (plasma, evaporation)

Protein, water, NaCl

Ileostomy losses (ileal fluid)

water, NaCl

Haemorrhage losses (blood)

RBCs all electrolytes

Diabetes insipidus losses (urine)

water

Addisons or diurteics use losses (urine)

NaCl, water

sepsis, cirrhosis (third space)

Protein Nacl, water

When do need to be cautious when giving fluids and consider individualisation of fluids regimes

• Elderly (20-25 ml/kg/day)
• obese (use IBW and don't go over 3L/ day)
• Heart failure
• renal failure
• liver failure (low albumin)
• oedema
• electrolytes derangement

Assessing fluids requirements

• History
• examination
• Bedside tests
• Investigations
• Normal or altered physiology
• Individual differences
• co- morbidities
• iatrogenic drugs
• Re-assess post-interventions

Hypovolemia (assessing fluid requirements)

clinical

• thirst
• cool extremities
• hypotension
• increased RR
• Tachycardia
• increased capillary refill time
• reduced UO
• reduced GCS
• loss of skin turgor
• Absence of JVP patient at 45 degrees
• Postural BP drop
• fluid balance charts

Biochemical

• FBC (hematocrit)
• raised urea/ creatine
• Hyperkalemia/ natremmia
• Hypercalcemia/ meatbolic acidosis
• raised BM/Ca2+
• CVP need cenral line
• esophgal doppler
• EchoCardiogram (collapse of LV)

Hypervolemia (assessing fluid requiremints)

Symptoms/Signs

• Raised JVP, patient at 45°
• Generalised oedema
• Increased weight (need baseline)
• Ascites
• Pulmonary oedema
• Increased RR
• Crackles
• Orthopnoea
• Fluid balance charts

Biochemical

• Blood tests
• Raised urea/creatinine (often reflects CRF)
• Raised LFTs (hepatic congestion)
• Hyponatraemia
• CVP Need a central line
• Oesophageal doppler
• Echocardiogram ( ?reduced LVEF, RWMA, Distended RV)

Delivery mothods of IV fluids

Peripheral

◼ Venous cannula (Venflons)

◼ Intra-osseous

◼ (Subcutaneous)

Central access:

◼ Central line

◼ Jugular, femoral, subclavian

◼ Peripherally-inserted central catheter (PICC)

◼ Hickman (tunnelled-line)

◼ Port-a-cath. Subcutaneous, accessible, needle-able reservoir

Complications of Peripheral lines

◼ Extravasation

◼ Thrombosis of peripheral veins

◼ Infection – phlebitis / cellulitis (VIP score to monitor, ANTT)

◼ Air embolism

central line complications

◼ Mis-insertion: pneumothorax, arterial bleed / dissection

◼ Infection – particular concern re: septic emboli / endocarditis

◼ Thrombosis and embolism

◼ Embolisation of the line

◼ Erosion

◼ Air embolism

Prescribing

Drug Chart

◼ Dedicated section

◼ Can also be written on Once Only/Stat section

◼ State

◼ Type of fluid

◼ Volume

◼ Drugs/Electrolytes to be added

◼ Rate (mls/hr) AND/OR time to be given over

◼ (Signature + bleep)

Prescribing

Notes

◼ Intention

◼ The intended fluid/electrolyte prescription over the next 24hrs

◼ Targets e.g.

◼ What to do if these are NOT met (for on-call Dr)

◼ Cautions/review points e.g.

Crystalloid pros and cons

Pros

◼ Safe (save AE determined by volume/electrolytes)

◼ Cheap

◼ Constituents determine distribution

◼ Na+ - ECF, Dextrose – ECF/ICF

Cons

◼ Remain in the intravascular space for less time (~45mins)

◼ Thus need greater volume to achieve effect (3-4L crystalloid/1L blood)

colloid pros and cons

Pros

◼ Remain in the intravascular space (dependent on MW)

◼ Can act as ‘plasma expanders’

Cons

◼ Cost

◼ ‘Hidden’ electrolytes

◼ Potential allergens

◼ Effect coagulation (increased bleeding risk in high doses)

◼ Renal: (predominantly HES)(Osmotic nephrosis,Failure)

common crystalloid fluids

1. Saline (0.9, 0.18, 1.8 %NaCl)
2. Hartmanns (Na lactate)
3. Sugar (5, 10 , 20, 50%)
4. Bicarbonates (NaHCO3) (1.26, 8.4%)

electrolytes are normally added to

saline/sugar

common colloid fluids

1. gelatins
2. starches
3. blood products (FFP, Packed cells, albumin(HAS 4.5%, 20%), cryoprecipitate)

What is in Hartmanns (mmol/l)

• the physiological fluid
• Na 131
• Cl 111
• K 5 > not significant, caustiond (CRF, AKI)
• Ca 2
• Lactate 29 > metabolised to HCO3 managed by liver, caustions (LF, DKA)

Why Fluid Challenge?

• Achieve a small but rapid increase in intravascular volume
• to assess the whether the patient is hypovolaemic and would benefit from further IV fluids

How:

◼passive leg raise

◼ Fluid challenge (Deliver 250-500mls fluid via a largish-bore cannula over 5mins)

Assess

◼ Clinical measures e.g. JVP/lungs/RR/HR/BP/UO

◼ Ideally: CVP, oesophogeal doppler

◼ NOT: Increase maintenance fluids