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1. Perioperative Fluid Management Presented by: Int. ???
Supervised by: VS. ???
3. Background
4. Background Traditional concept of fluid loading.
Preoperatively fasted patient hypovolemic due
to ongoing perspiration and urinary output.
Insensible lost increased dramatically during
surgery when skin barrier is broken.
Unpredictable fluid shift toward 3rd space
requires substitution.
Hypervolemia harmless because kidneys
regulate the overload.
5. Background Recently, perioperative fluid management
has become a topic of debate –
Colloids vs Crystalloids?
Amount?
Purpose of this review is to promote a
rational approach to perioperative fluid
management .
6. Fluid Optimization
7. Fluid Optimization Principle goal is to optimize cardiac preload
Optimizing ? Maximizing.
However, individual patient’s preoperative
volume status, exact target unclear.
Cannot access blood volume (preload) routinely.
Double label method (gold standard)
– invasive, complex, personnel intensive.
8. Fluid Optimization Double label method – dilution technique.
Plasma volume: ICG.
Red cell volume: sodium fluorescein-labelled
autologous RBCs.
Whole blood volume = PV + RCV.
9. Fluid Optimization Other indices ?
PWP and CVP.
-- Cannot accurately predict EDV due to
variations in ventricular compliance.
-- Changes cannot accurately reflect changes
of EDV or SV.
11. Fluid Optimization Goal directed approach – measure volume
responsiveness.
Systolic pressure and pulse pressure variation
predict volume responsiveness. Outcome ?!
Stroke volume maximization via esophageal
Doppler-guided fluid boluses improve
outcome, but cannot be routinely applied.
12. Fluid Optimization Protocol-based fluid restriction in major
abdominal surgery.
Reduced perioperative complications such as
cardiopulmonary events, bowel motility
disturbance.
Improved wound/anastomotic healing and
reduced hospital stay.
13. Fluid Optimization Lobo et al. reviewed 20 adults after elective
colonic resection.
Aggressive intraoperative fluids 20 mL/kg/hr.
Postoperatively, randomly assigned to
restrictive (< 2 L/day) or standard protocol (=
3 L/day).
Latter caused significant weight gain, later
return of bowel function and prolonged
hospital stay.
14. Fluid Optimization Mackay et al. did not confirm such findings,
despite incomparable protocols.
Standard group was treated “too restrictively”.
? Not enough to cause measurable harm!
15. Fluid Optimization Brandstrup et al. reported perioperative
fluid restriction (mean 2740 vs 5300 mL)
reduced complications – anastomotic
leakage, pulmonary edema, infection.
No patient developed acute renal failure.
16. Fluid Optimization Holte and Kehlet performed systematic
review of 80 randomized clinical trials and
recommended avoiding fluid overload in
major surgical procedures.
17. Fluid Shifting
18. Fluid Shifting Fluid shifting out of the vasculature is an
often recognized phenomenon during and
after surgical procedures.
Direct, indirect blood volume measurements
shown major surgery causes a deficit of
3~6 L in the sensible perioperative fluid
balance., i.e., measurable input minus
output.
20. Fluid Shifting Fluid shifting is not only an intraoperative
problem but a postoperative problem.
Peak of fluid shifting at 5 hrs after trauma
and persists up to 72 hrs depending on
location and duration of surgery.
21. Fluid Shifting Lowell et al. found 40% of patient admitted
to SICU had an excessive increase in body
water of more than 10% of preoperative
weight.
Perioperative weight gain:
Marker of fluid storage outside circulatory space.
Inversely related to patient outcome.
23. Fluid Shifting Assumed hypovolemic state after:
Fasting.
Insensible perspiration.
Fluid-consuming third space.
? Preoperative loading > 2 mL/kg/hr fasting.
Induction anesthesia.
Lowered sympathetic tone, relative hypovolemia.
? Fluids instead of vasopressors -- threaten
kidney function?!
24. Fluid Shifting Basal evaporation = 0.5 mL/kg/hr
? 1 mL/kg/hr during large abdominal
surgery with bowel exposure.
After extended fasting:
ECV slightly decreases.
Intravascular volume remains within normal range.
25. Fluid Shifting – Footnote Insensible water loss.
Breathing – 500 to 700/24 hours.
Skin – 300 mL/24 hours.
? Increases with fever, tachypnea, mechanical
ventilation, surgery, etc.
26. Fluid Shifting Hypervolemic loading with crystalloids:
? Physiologically distribute within the ECV.
? 4/5 will leave the vasculature.
Hypervolemic loading with colloids:
? 60% do not remain in the vasculature
due to volume effect.
28. Fluid Shifting Consequently, traditional fluid loading
? Fluid shifting!
? Interstitial edema!
? Adversely affect patient outcome!
29. The Endothelial Glycocalyx
30. The Endothelial Glycocalyx Healthy vascular endothelium coated
by endothelial glycocalyx – a layer of
membrane-bound proteoglycans and
glycoproteins.
31. The Endothelial Glycocalyx Glycocalyx affect endothelial permeability.
Prevent leukocyte and platelet adhesion.
Decreases inflammation.
Bounds plasma proteins and fluids.
? 700 ~ 1000 mL of “non-circulatory” plasma
fixed within.
? Maintains “oncotic gradient” despite
intravascular and extravascular equilibration.
32. The Endothelial Glycocalyx Fluid shift into the interstitial space can be
divided into two types:
Type 1 – physiologic shift.
-- Colloid-free fluid and electrolytes.
Type 2 – pathologic shift.
-- Protein-rich fluids.
-- Functionally altered vascular barrier.
33. The Endothelial Glycocalyx Type 2 shift, result of 2 iatrogenic problems.
Surgical:
Endothelial damage due to mechanical
stress, endotoxin exposure, ischemia-reperfusion
injury and SIRS.
Anesthesiolgic: Acute hypervolemia!
34. The Endothelial Glycocalyx Preserve endothelial glycocalyx to inhibit
type 2 shift.
Inflammatory mediators ,stress, ischemia-
reperfusion injury can hardly be avoided.
Maintaining vascular normovolemia.
? Key to protection of endothelial glycocalyx .
? Prevent interstitial edema.
35. Approach to Fluid Management
36. Approach to Fluid Management The intravascular deficit after fasting is
usually low.
Basal fluid loss via insensible perspiration
approximately 0.5 mL/kg/hr,
? Extending to only 1 mL/kg/hr during
major abdominal surgery.
37. Approach to Fluid Management Minimize type 1 shifting.
Use crystalloids only when replacing urine
production and insensible perspiration.
Use colloids or blood products for substitution
of acute blood loss.
Minimize type 2 shifting.
Goal-directed method with available parameters.
Conservatively to avoid acute hypervolemia.
Use colloids instead of crystalloids.
