Periop fluid th ent 7.2021.a

Perioperative fluid management
-Best practices-
Helga Komen, MD
Assistant Professor of Anesthesiology
Department of Anesthesiology
Washington University in St. Louis

Why it can be complicated?
• We challenge the patient with:
Preop
• Fasting
• Bowel prep
Intraop
• Surgical stress – blood loss, perspiration
Postop
• No p.o. intake
Perioperative Fluid Management

We demand:
– Hemodynamic stability
– Perfussion of tissues adequate
– Avoidance of overload
– Avoidance of AKI
….In order to guarantee best surgical outcomes!
Why it can be complicated?

Parameters based fluid replacement:
• Blood pressure
• Heart rate
• Urine output
• ABG/VBG (pH, Ht, electrolytes, BE)
• EBL
• Pulse pressure variation (PPV), a. line
• Stroke volume variation (SVV), Lidco monitor
How are we doing it?

We can still miss manage!
Bellamy MC, BJA, 2006.

Goals of Periop Fluid Management
Maintain optimal intravascular volume in order to
optimize O2 delivery!
replace TIMELY insensible and surgical losses

• Oxygen Delivery - DO2 - is the oxygen that is delivered to the
tissues
DO2 = Cardiac Output (CO) x Oxygen Content (CaO2)
– Cardiac Output (CO) = HR x SV
– Oxygen Content (CaO2):
• (Hgb x 1.39) x O2 saturation + PaO2 (0.003)
• Hgb is the main determinant of oxygen content in the blood
Goals of Periop Fluid Management

Preop Fluid Management
• Aim - maintain euvolemia!
• Fasting
- Solids allowed up until 6h before anesthesia (light meal)
- Clear fluids up until 2h before induction
- water, fruit juices without pulp, carbonated beverages,
carbohydrate-rich nutritional drinks, clear tea, black coffee
- Per ERAS protocol - 2 bottles (12 fl oz) Gatorade night before surgery, 1
bottle 2 hours before surgery (DM patients take water)
• Bowel prep
Preop negative balance is minimal!
< 500 mL crystalloids in Preop!

Intraop fluid management
• Aim - maintain central euvolemia, avoid salt and water
excess!
• Surgical procedure <3hrs
– average 1-2L LR
• Major surgery (>3hrs, e.g. free flap)
– Fixed-volume fluid management
– Liberal approach fluid management
– Restrictive fluid management (zero balance)
– Goal-directed fluid therapy (PPV/SVV)
Girish P Josh I, Intraoperative Fluid Management, UpToDate

– Replacement of preexisting fluid deficit
– Replacement of insensible losses
– Replacement of “third space” losses
– Replacement of blood loss
– Maintenance fluid 4-2-1 rule
– Perioperative weight gain >10%
- Marker of fluid storage outside circulatory space.
- Inversely related to patient outcome.
Intraop fluid management - strategies
Fixed-volume fluid management

Intraop fluid management - strategies
Liberal approach fluid management
• E.g.
– bolus of a balanced salt crystalloid solution administered at a dose of
10 ml/kg body weight during the induction of anesthesia
– followed by 8 ml/kg/hr until the end of surgery.
= pt 100kg
- induction 10mlx100kg=1000L crystalloids
- 8mlx100kg/hr=800ml/hr (e.g. 6hrs case total 4800L)

Intraop fluid management – strategies
Restrictive fluid management (zero balance)
• E.g.
– bolus of a balanced salt crystalloid solution administered at a dose of 5 ml/kg
body weight during the induction of anesthesia
– followed by 5 ml/kg/hr until the end of surgery.
– postop infusion 0.8ml/kg/hr
– vasopressors could first be considered for treating hypotension without
evidence of hypovolemia
– the total administration of fluid during the first 24-hour period was expected
to be approximately half that in the liberal fluid group
= pt 100kg
- induction 5mlx100kg=500L crystalloids
- 5mlx100kg/hr=500ml/hr (e.g. 6hrs case total 3000L)

• randomly assigned 3000 patients
• restrictive or liberal intravenous-fluid regimen during and up to 24
hours after surgery
• The primary outcome was disability-free survival at 1 year
• 1490 patients in the restrictive fluid group had a median
intravenous-fluid intake of 3.7 liters (interquartile range, 2.9 to 4.9),
as compared with 6.1 liters (interquartile range, 5.0 to 7.4) in 1493
patients in the liberal fluid group (P<0.001)
• The rate of acute kidney injury was 8.6% in the restrictive fluid
group and 5.0% in the liberal fluid group (P<0.001)
• Therefore, as both a severely restrictive fluid regimen and fluid
overload are detrimental, a zero-balance fluid therapy should be
sought while maintaining kidney function

• Every patient has individualized fluid management plan!
• Goals (set of cardiovascular indices) – BP, HR, SV, CI, urine output,
PPV (pulse pressure variation)
• Use low-volume infusion of balanced crystalloids (LR)
• Avoid boluses
• Keep PPV <13% - minimally invasive cardiac output monitoring
• End point - Avoid perioperative weight gain >10%
Heming N at al, BJS, 2020.
Intraop fluid management – strategies
Goal directed fluid therapy

• Maintenance fluids at 1-2 ml/kg/hr of Ringer’s Lactate
– 250 ml boluses of crystalloid (LR) or 5% albumin to counter hypotension (4ml/kg) – SV
increase >10%
– Fluid responsiveness is typically defined by a SV increasing by 10% or more following fluid challenge.
• Maintain SVI (stroke volume index) 35-45 or SVV/PPV (stroke volume
variation/pulse pressure variation) of < 13 %
• Cardiac Index (CI) >2.5 l/min/m2
• Use vasopressor infusion (phenylephrine) as needed to maintain blood pressure.
• Blood transfusion as guided clinically and by lab results.
– transfusion trigger hematocrit of < 25% (may be higher if patient has coronary disease)
Goal directed fluid therapy (GDFT)
-part of ERAS protocol (Enhanced Recovery After Surgery)-

• pulse pressure variation
Goal directed fluid therapy (GDFT)-
Monitoring
• Lidco

– Reduced perioperative complications
• cardiopulmonary events - respiratory failure
• bowel motility disturbance – ileus
– Improved wound/anastomotic healing
– Reduced hospital stay
Goal directed fluid therapy
part of Enhanced Recovery After Surgery (ERAS) protocol

ERAS protocol (Enhanced Recovery After Surgery)

ERAS timeline
• 1990s – dr. Henrik Kehlet (University of Kopenhagen) –
concept of multimodal surgical care
• 2001. – ERAS Study Group – UK, Sweden, NL
• 2005. – 1st ERAS protocol – Colorectal surgery
• 2016. – ERAS for head and neck surgery

Goal directed therapy
as part of ERAS
• Intraoperative management of fluids during surgery should be
guided by goal-directed therapy (GDT) rather than predetermined
calculations.
• GDT utilizes a combination of fluids and inotropes to optimize
perfusion during surgery
• It is important to identify that urine output does not play an
important role in GDT (oliguria can be an expected outcome of the stress
response associated with surgery, e.g. UO 0.3 ml/kg/hr.)
• In many institutions, as we await adequately powered trials,
perioperative fluid management protocols currently include use of
GDT.

Guidelines from the American Society for Enhanced Recovery (ASER) and
Perioperative Quality Initiative (POQI) for the perioperative
management of fluids using goal-directed therapy (GDT) in enhanced recovery
pathways (ERPs).

- We recommend that both perioperative fluid choice and
therapy should be individualized.
- Patients should receive fluid therapy guided by predefined
physiologic targets.

- 2019.
- six studies with a total of 562 participants
- In 5 studies - crystalloids were used for basal infusion and colloids for
boluses, and in 1 study - colloid was used for both basal infusion and
boluses.
- Based on very low-certainty evidence, it is uncertain whether
restrictive fluid therapy (RFT) is inferior to GDFT in selected
populations of adults undergoing major non-cardiac surgery.
GDF vs. restrictive

Anesthesiology 2019; 130:825–32

Postop fluid management
-day of surgery/POD1-
• Immediate postop – 1.5 ml/kg/h LR or NS
• >12hrs postop – tube feed/p.o (It is recommended that patients
receive 25-35 ml/kg of water per day in the recovery period )
Goal - optimal perfusion of tissues by achieving preoperative DO2
values
• HR (~70/min), BP (120/80 mmHg), MAP (~70 mmHg)
• Labs – Na, K, Cr
• UO (>0.5ml/h)
– Some degree of oliguria in response to the stress of surgery appears to be a normal and
predictable physiological response, 0.3-0.5 ml/kg/hr UO (This may be due to the release
of vasopressin in response to the stress of surgery)

Crystalloids
• Combination of water and electrolytes
– Balanced salt solution: electrolyte composition and osmolality
similar to plasma (lactated Ringer’s, Plasmalyte A, Hartmann`s),
containing buffer (lactate).
– Hypotonic salt solution: electrolyte composition lower than that
of plasma (D5W).
– Hypertonic solutions - fluids containing sodium concentrations
greater than normal saline.
• Available in 1.8%, 3%, 5%, 7.5%, 10% solutions.
• Hyperosmolarity creates a gradient that draws water out of cells;
therefore, cellular dehydration is a potential problem.
– Blood loss replaced in ratio 1.5:1

Crystalloid Composition

Colloids
• Fluids containing molecules sufficiently large enough
to prevent transfer across capillary membranes.
• Examples: hetastarch (Hespan)(Voluven), albumin,
and dextran.
• Colloids used to replace plasma volume loss
– Blood loss replaced in ratio 1:1

Colloids - Albumin
• Purified human protein from plasma
• Pasteurized at 60oC
• Half-life 16 hours
• 90% remains intravascular at 2h

Effects of various fluids on ECV vs IVV
Perioperative Fluid Management ECV-extracellular volume
IVV-intravascular volume

- Aim - compare the effects of crystalloids and colloids on the microcirculation
during free flap surgery when management was guided by detailed haemodynamic
assessment.
- Patients - either intra-operative crystalloid (LR, n 15) or colloid (6% hydroxyethyl starch,
HES, n 15) solutions.
- Interventions -The microcirculatory effects were assessed by laser Doppler flowmetry
(PeriFlux 5000 LDPM), with the probe placed on the flap and on a control area.
- Conclusion - there was no difference between the effects of crystalloids and colloids
on the microcirculation.

Transfusion Therapy
When is Transfusion Necessary?
• “Transfusion Trigger”: Hb/Ht level at which transfusion
should be given.
– Varies with patients and procedures
• av. 8/25
• 10/30 in cardiac pts.
• Tolerance of acute anemia depends on:
– Maintenance of intravascular volume
– Ability to increase cardiac output

Component Therapy
• A unit of whole blood is divided into components; Allows
prolonged storage and specific treatment of underlying
problem with increased efficiency:
– packed red blood cells (pRBC’s)
– platelet concentrate
– fresh frozen plasma (contains all clotting factors)
– cryoprecipitate (contains factors VIII and fibrinogen; used in Von
Willebrand’s disease)
– albumin
– plasma protein fraction
– leukocyte poor blood
– factor VIII
– antibody concentrates

Packed Red Blood Cells (PRBC)
• 1 unit = 350 ml. Hct. = 70-80%.
• 1 unit pRBC’s raises Hgb 1 gm/dL.
• LR has calcium which may cause clotting if mixed
with PRBCs.
• High levels of free K+
• Cell saver – cardiac/ortho/spine surgery

Complications of Blood Therapy
• Transfusion Reactions:
– Febrile: most common, usually controlled by
slowing infusion and giving antipyretics
– Allergic: increased body temp., pruritis, urticaria.
Rx: antihistamine,discontinuation. Examination of
plasma and urine for free hemoglobin helps rule
out hemolytic reactions.

• Periop fluid management is very important for optimal surgical outcomes
• Main goal is to maintain euvolemia periop
• Best practice is to keep p.o. intake as late as possible preop (clear fluids, 2hrs) and
resume as early as possible postop (12hrs)
• Goal directed fluid therapy is probably the best strategy for intraop fluid management
• Optimization of intravascular status with goal PPV<13%
• Balanced crystalloid infusions (LR) to replace insensible losses – 1-2ml/kg/hr
maintenance (intraop/postop). Bolus 250 ml if needed
• Start replacing blood loss with colloids (bolus 250ml)
• Avoid perioperative weight gain >10%
Conclusions

Questions?
Moscenicka Draga, Croatia

Periop fluid th ent 7.2021.a

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