A talk by Robert Hahn at the 2017 meeting of the Scandinavian Society of Anaestesiology and Intensive Care Medicine. All of the conference content can be found here: https://scanfoam.org/ssai2017/ Developed in collaboration between scanFOAM, SSAI and SFAI.

1. Robert Hahn, MD, PhD
Research Director, Södertälje sjukhus
Adj. Professor of Anaesthesia & Intensive Care, Karolinska institutet
Malmö 2017
Basic science of fluid therapy

2. Resuscitation fluids
Fluid Management
Crystalloid Colloid
BalancedUnbalanced Natural
Sodium Chloride
0.9%
Plasma-Lyte
Ringer’s Lactate
Ringer’s Acetate
Hartmann’s
Human Albumin
Blood
Different fluids with different modes of action,
and different side effects
Different fluids with different modes of action,
and different side effects
HES
Dextran
Gelatin
Synthetic
MD-IV-25 09-2013

3. Differences between crystalloids and colloids
Crystalloids
> No allergic effects
> Distribution phase
Colloids
> Allergy
— Gelatin 0.35%
— Dextran 0.27%
— Albumin 0.10%
— HES 0.06%
— Severe in 20% of patients
– (Laxenaire et al.1994)
> No distribution phase
3

4. 4
Hahn RG. Crystalloid and colloid fluids. In: Prabhakar H, ed.,
Essentials of Neuroanesthesia, San Diego: Academic Press, 2017: 827-832.
Infusion of 1 L of Ringer´s versus 0.5 L of colloid

5. Is the endothelial glycocalyx layer responsible?
Highly unlikely, because the reflection coefficient for electrolytes is very low.
Electrolytes (2 Å) always pass easily through the endothelial pores (45 Å).

6. Guyton´s textbook
Interstitiet is a gel that initially
gives high resistance to volume
expansion.
Water volume is moved slowly,
nutritients fast.
When the interstitium is expanded
it loses elasticity.

7. Hahn RG: Fluid absorption in endoscopic surgery. BJA 2006; 96: 8-20
Interstitial dilatation in rabbit heart
2 hrs after receiving 100 ml/kg of glycine solution

8. Distributed fluid returns more slowly to the
plasma when an infusion is given at a high rate.
76 males
Acta Anaesthesiol Scand 2016; 60: 569-78

9. Is the turnover of crystalloid fluid
changed in certain states?
• Distribution is temporarily arrested in acute
hypotension, such as during induction of anaesthesia.
•
• Elimination is reduced during general anaesthesia.

10. Eur J Anaesth 2016; 33: 475-482
Change in the rate of elimination

11. Crit Care 2012

12. • Hemodilution, urinary excretion, arterial pressure and heart rate were
measured every 5-10 min during 78 infusions of crystalloid fluid.
• 30 conscious volunteers.
• 48 anesthetized patients (19 laparoskopies and 29 thyroid surgeries).
Total 2,108 points of measurement.
• Population kinetic (mixed model) analysis of all data on a single
occasion, using Phoenix NLME software.
• Approximately 15 co-variates were evaluated and were tested for
interaction with the model parameters.
Anesth Analg 2017; 124: 1824.

13. Crystalloid kinetics, dependency on MAP
Hahn RG. Crystalloid and colloid fluids. In: Prabhakar H, ed.,
Essentials of Neuroanesthesia, Academic Press, 2017: 827-832.

15. Colloid fluid

16. Colloid infusions
Infusion of 800 ml over 30 min in volunteers (three studies).
Increase the blood volume 80-90% of the infused volume. No distribution effects.

17. Differences between crystalloids and colloids
Crystalloids
Distribution is temporarily arrested in
acute hypotension.
Re-distribution is hampered by fast
infusion, probably also by large
volumes.
Elimination is reduced by a low MAP
Colloids
• Intravascular persistence is quite
similar to the half-life in volunteers
• Intravascular persistence is reduced
by shedding – but how much?
• MAP probably not important.
17

18. BJA 2012; 109: 168

19. Oedema
• Crystalloids Low MAP, fast infusion, old age
• Colloids Capillary leakage of colloid?
• Both together Crystalloid eliminated slowly

20. Plasmadilution
(ratio)
Time (min)
Oedema is greater when
a crystalloid is preceded
by a colloid
Crit Care 2013; 17: R104
1. HES leaks and attracts fluid in the interstitium.
2. Remaining HES increases COP which retains fluid in the kidneys.

21. 21
Saudi J Anaestesiol 2017; 11: 144-151

22. Clinical views

23. Purpose
To provide adequate perfusion to sustain metabolic
demands and promote aerobic metabolism.
Fluids in intensive care
How?
Use fluid only in preload-dependent patients and
when end-organ perfusion goals are not met.
Lira- Pinsky: Intensive Care. In: Hahn RG. Clinical Fluid Therapy
in the Perioperative Setting. Cambridge Medicine 2016.

24. Shock
Hypovolaemic shock (such as haemorrhage)
Autonomic system intact – fluid works well.
Distributive shock (sepsis, high spinal, GA)
Autonomic system works poorly –
combine fluid with adrenergic drugs.
Can lead to cardiac arrest if these types of shock are combined.

25. Fluid balance method
Sum up known and perceived fluid losses and replace them
Outcome-oriented approach
Based on postoperative complications associated with different
fluid programs (such as restrictive or liberal)
Goal-directed fluid therapy
Fluid is given to reach hemodynamic goals
Perioperative Fluid Therapy
THREE STRATEGIES WHEN PROVIDING FLUID

27. Outcome-oriented approach
• 3-5 ml/kg/hour balanced crystalloid fluid.
• 2 ml/kg/hour is too little, and increases the incidence of
nausea.
• 1-2 ml/hour needs to be balanced with goal-directed fluid
therapy, or by low-dose epinephrine

29. 29
Adverse effects of crystalloid fluids
(according to experiences from general surgery)
> 2 L Paralytic ileus – longer GI recovery time.
6 L Pulmonary infection and congestion,
sepsis (after GI surgery), poorer wound healing.
> 6 L Pulmonary oedema (might be fatal).

30. CONCLUSIONS

31. Conclusions, Crystalloids
• Volume kinetics is pharmacokinetics of infusion fluids.
• Distribution of crystalloid fluid requires 30 min to be completed,
both in conscious and anesthetized patients.
• Distribution is temporarily arrested during induction of anesthesia.
This is due to the reduction of MAP.
• Urinary excretion is very low during general anesthesia. Recent data
suggest a direct dependence on MAP and (inversely) on age.

32. Conclusions, Colloids
• Colloids have no distribution phase, but an intravacsuar persistence
half-life of 2-3 hours.
• Colloid fluid kinetics is probably not affected by MAP.
• Crystalloid fluid infused after a colloid will be poorly excreted and
aggravate peripheral edema.
• Colloid fluid may promote diuresis during surgery, but acts to retain
fluid during the postoperative phase.

33. Now to the main speakers!

34. Half-life of Voluven = 120 min, Vd = 3.0 L
Crit Care 2013; 17: R104
Plasma
dilution
(ratio)

35. Preliminary data from an ongoing trial with albumin 20%
in Linköping and Karolinska Solna
Plasma
volume
expansion
200 ml of albumin 20% is infused over 30 min in volunteers (N=15)
and postoperative patients, major surgery (N=15)
MAP has no influence on the kinetics.

36. Anaesthesiol Intensive Therapy 2014; 46: 342-349.
If MAP decreases by 20%
distribution of crystalloid fluid
becomes arrested.
100% of the infused fluid then
remains in the blood
Reason: Starling mechanism
Change in the rate of distribution

37. Leakage of macromolecules
(albumin) increases by a
factor of 3 in septic shock
Lancet 1985; 325: 781-784