Fluids Flashcards
Describe the fluid compartments of a 70 kg man
TBW is 60% of 70kg = 42 L
2/3 ICF = 28 L
1/3 ECF = 14 L
- Plasma 3L
- Transcellular 1L
- Interstitial 10L
What proportion of IV crystallioid remains intravascular and why
1/3rd (Fluid distributes evenly into extracellular fluid - 1/3rd of which is intravascular and 2/3rds of which is extravascular
therefore 3 x as much crystalloid is require to achieve the same volume expansion as a volume of colloid
How long do colloids stay intravascular
Until the large colloid molecules are metabolized (providing the endothelium is intact)
2 -3 hours
Why are crystalloids retained in the ECF and not the ICF. Describe the distribution of 5% dextrose in water
Equal osmolarity to ICF.
The dextrose in D5W is metabolized and the remaining free water distributes into both the ICF and ECF
Where do the following fluid types distribute?
1. D5W
2. Normal Saline
3. Colloid
- All compartments
- Extracellular compartments
- Vascular compartment
What are the daily requirements for:
Water
Na
K
Mg
Ca
Phosphorus
Glucose
Energy
Protein
PER DAY:
30 ml/kg Water
1 mmol/kg Na
1 mmol/kg K
0.1 mmol/kg Mg
0.1 mmol/kg Ca
0.4 mmol/kg Phosphorus
2.5 g/kg Glucose
25 kcal/kg/day
1.25 g/kg/day
Compare the composition of maintelyte to D5W and Rehydration solution
MAINTELYTE
Per 1000 mls
Na 40 mmol
Cl 40 mmol
K 20 mmol
Mg 1.5 mmol
Acetate 23 mmol
Glucose 50g (which is 5% or 50mg/ml)
Osmolarity 402 mOsm/L
D5W
Per 1000 mls
Glucose 50g (which us 5% or 50mg/ml)
Osmolarity 252 mOsm/L
REHYDRATION
Per 1000 mls
Na 77
Cl 77
Glucose 90g
Osmolarity 406
Compare the composition of normal saline, hypertonic saline (5%) and Nacl 0.45%
NaCl 5%
512 mmol Na
512 mmol Cl
Osmolarity = 1028
NaCl 0.9%
154 mmol Na
154 mmol Cl
Osmolarity = 308
NaCl 0.45%
77 Na
77 Cl
Osmolarity = 154
Compare the composition of:
Plasmalyte L (Balanced salt solution)
Ringers Lactate (Hartmann’s solution)
PLASMALYTE L
Na 140
Cl 98
K 5
Mg 3
Acetate 27
Gluconate 23
Osmolarity = 294
RINGERS LACTATE
Na 131
Cl 111
K 5
Mg 0
Ca 2
Lactate 29
Osmolarity = 280
Compare the composition of Voluven to Volulyte
Voluven
(Maize) Hydroxyethyl Starch 6% (130/0.4) 60 grams
Na 154
Cl 154
Osmolarity = 308
(Maize) Hydroxyethyl Starch 6% (130/0.4) 60 grams
Na 137
Cl 110
K 5
Mg 1.5
Acetate 34
Osmolarity = 286
Compare the composition of Albumin 30% to Albumin 5%
PER 1000 mls
30% ALBUMIN
Na 130
Cl 130
K 3.5
ALB 200g
Ca 1.2
Osmolarity = 260
5% ALBUMIN
Na 130
Cl 130
K 3.5
ALB 5g
Ca 1.2
Osmolarity = 260
Describe the concept of deresusciation
Overzealous fluid causes harm
- Glycocalyx degradation and endothelial injury
The conceptual ROSE model describing the 4 fluid phases:
START IV FLUID ADMINISTRATION
R (Resuscitation) - patient resue
- ? Shock
- Triggers to START IV fluids: MAP < 65. PLR positive. PPV/SSV > 15%. CI < 2.5. Lactate > 3.
- Early Adequate Fluid Management (EAFM) = 4ml/kg bolus every 5 - 10 mins
STOP IV FLUID ADMINISTRATION
O (Optimization) - organ rescue
- ? Fluid unresponsive
- Maintenance. Avoid fluid overload.
- Triggers to STOP IV fluids: MAP > 60. PLR negative. PPV/SSV < 12%. CI >2.5. Lactate <2.
- Aim for neutral fluid balance
START FLUID REMOVAL
S Stabilization) - organ support
- Late Conservative Fluid Management (LCFM) = 2 x negative fluid balance within 1st week after insult
- Triggers to start fluid removal: MAP > 65. PF< 150. PLR negative. PPV and SVV <12%. IAP > 15.
STOP FLUID REMOVAL
E (Evacuation) (Elimination) - organ recovery
- Late Goal Directed Fluid Removal and negative fluid balance
- Triggers to stop fluid removal: MAP < 55. PPV, SVV > 15%.PLR positive. Lactate > 2.5.
When should colloids (voluven and albumin) not be used
Resuscitation in septic shock
Greater cost and no demostrated advantage
Avoid in patients with TBI (?BBB)
Pulmonary oedema (fluid overload)
Renal failure and oli/anuria
Hypernatraemia
How is fluid status assessed
Clinically
Biochemical
Charted Fluid Balance
Insensible losses
Under what circumstances is the Vigileo inaccurate?
- Arrythmia
- Spontaneously breathing
- Vt < 8 ml/kg
BUT trends can be helpful
