1. Steph Tilston Anaesthetic SpR Hurstwood Park Neurological Centre
Hyperosmolar/Low Volume Resuscitation and Head Injury – A review of Current Evidence
Steph Tilston
Anaesthetic SpR
Hurstwood Park Neurological Centre

2. Background Osmotherapy used since early 20thC to treat raised ICP
First systemic studies in 1960’s
Military use
Much animal based research
Increased interest over last 20 years
Clinical trial evidence emerging
Sheep bled out to shocked state in original study..CO and MAP restores with as little as 10% vol lost given
Easier for army medics to carry small bags of fluids
Found those soldiers receiving this had better outcomes
Early volume restoration

3. Originally hypertonic saline used
Effects found to be relatively short lived
Combined with colloid solution
Volume effects substantially additive to that of colloid alone
Best risk/benefit ratio
% NaCl with 6-10% dextran 60/ or 6-10% hydroxyethylstarch 200,000

4. ‘Rescueflow’ by vitaline pharmaceuticals 6% dextran 70 in 7.5% NaCl
‘Hyperhaes’ (HHES)
Focus is on pre-hospital treatment of severe hypovolaemia/shock

5. Uses of hypertonic solutions
Primary volume resuscitation from severe hypovoleamia and shock
Head injury with raised ICP
Spinal shock
Sepsis
Burns
Pre CPB priming
AAA

6. Body fluid compartments
total body water 42l

7. Proposed mechanisms of action
Rapid mobilisation endogenous water from intracellular compartment – large reserve
Increases plasma volume by 3-4 x volume infused
Normalising endothelial and red blood cell volume and microvascular blood flow
Reperfusion ischaemic areas
Endothelial cell volume esp increases in shock/ ischaemia because of cell ATP loss and cell membrane exchange dysfunction
Leads to water accumulation within cells

8. Increased pulmonary gas exchange, R shift oxy-Hb dissociation curve
Increaded preload, cardiac index,PCWP
Direct myocardial stimulation
Peripheral vasodilatation, haemodilution
Redistribution blood flow esp mesenteric
Emerging evidence of immune modulation; decreased sticking and rolling leukocytes

9. Characteristics of hypertonic solutions
High crysalloid conc, eg Na, glucose, bicarb
Substantial but short lasting rise in plasma osmolarity
Normal range
Eg sodium, mannitol, glucose,bicarbonate previosly urea

10. evidence Huge amounts of animal studies
Human trials slow to show benefit. Difficulty in randomisation.crossover.
but increasing numbers of studies showing benefit
Large North and South America multi-centre trial on pre hospital saline/dextran v crystalloid for post traumatic hypotention
Increased survival in penetrating injuries / those requiring immediate surgery
Fewer complications

11. Meta-analysis of 8 trials, 1170 patients
significant improvement in 30 day survival esp.. sub-groups with severe trauma head injury with raised ICP
European research shows CVS benefits in Sepsis
Also in management of emergency AAA
CAB priming

12. In Raised ICP / cerebral oedeme
Prospective RCT
32 German neurosurgical patients
7.2%NaCl/starch v 15%mannitol
Statistically significant speed and degree of normalisation of elevated ICP
6.0 mins v 8.7 mins
57% v 48%
No clinically relevant effect on osmolarity
Mean dose 1.4 mls/kg

13. Severe sepsis Prospective bouble-blind RCT Brazilian ITU
Improvement in all CVS parameters
Few complications
But dubious study

14. Many animal studies show less MODS

15. Numerous animal studies
effectively stays outwith BBB
Direct osmotic effect
Initial effect lasts aprox 2 hrs
Maintained with infusion
^perfusion
decreased oedema and volume of contusion

16. Caution Patients with low cardiac reserve
Hyperosmotic states/electrolyte disturbances
Uncontrolled bleeding
phlebitis
Immunodilution?
Central pontine myelinolysis??
DKA, severe dehydration, alchohol poisoning
CPM too rapid correction low NA, delerium, spastic quadplegia…animal studies only

17. Further Research Exact MOA in humans Best mode of administration
Best dose
More quality trials!

18. The Future?
Hyperosmolar solutions with artificial O2 carriers