regarding perioperative fluid therapy

1. DR.YOGESH RATHOD
DEPARTMENT OF ANAESTHESIOLOGY
SETH GSMC & KEMH

2. GOAL-DIRECTED THERAPY
 Goal – improved tissue perfusion and clinical outcome
 Based on measuring key physiologic variables
 Cardiac output or
 Global O2 delivery
 Achieved with
administering fluids, and
possibly inotropes, vasopressors, vasodilators, and
RBCs
 Targets are defined physiologic endpoints and not dependant on
objective assessments of fluid status.

3. TECHNIQUES USED FOR PERIOPERATIVE GDT:
 Pulmonary artery catheter (PAC)
 Gold standard hemodynamic monitor,
 provides measured and derived values for Left and right heart filling pressures, mixed
and central venous saturations and CO.
 Esophageal Doppler monitor (EDM)
 ultrasound measurement of descending aorta blood velocity=> SV => CO
 Partial CO2–rebreathing technique [noninvasive cardiac output (NICO)],
 Lithium dilution [lithium dilution cardiac output (LiDCO)]
 Plethysmography and
 Gastric tonometry
 Thoracic Bioimpedance (non-invasively measures SV & CO through 4 surface ECG
electrodes)

4. TARGETS FOR GOAL-DIRECTED THERAPY ARE AS
FOLLOWS:
 Arterial blood pressure and waveform analysis (MAP >65 mm Hg)
 CVP (8-10 cm H2O)
 Echocardiography (No regional wall motion abnormalities)
 Lactate (<2.0 mmol/L)
 O2 extraction and venous O2 saturation (SvO2) or central venous
saturation (ScvO2)

5. APPROPRIATE FLUID SELECTION
 Crystalloids or Colloids for Intravascular Plasma Volume
Expansion.
 Crystalloids = most rational choice
replacement of evaporative losses,
maintenance fluid requirements, and
expansion of the entire extracellular fluid volume,
 Choice for plasma volume replacement not clear.
 Saline-Based or Balanced Solutions?
 Intraop Isotonic saline => postop hyperchloremic acidosis
 Excess NaCl and water load excreted slowly
 Rational to use Balanced Crystalloids

6. TYPICAL PRACTICAL APPROACH
Preoperative
 Oral clear fluid intake until 2 hours preop.
 Bowel prep in selected cases only and an infusion of 1 to 2 L of
balanced crystalloid with K+ supplementation for adequate hydration in
such cases.
 Chronic comorbidities assessment for influence on fluid and electrolyte
balance.

7. Emergency surgery
 Acute disturbances of fluid compartments.
Timely resuscitation guided by rational physiologic endpoints
 trends in blood pressure and heart rate
 Lactate
 urine output, and
 mixed or central venous O2 saturations.
 Upper GI losses quantified and replaced with isotonic saline.
 Lower GI losses with balanced crystalloid.
 K+ should be supplemented as appropriate.
Preoperative

8.  Intraoperative
 Balanced crystalloid used to replace the ongoing water and electrolyte losses.
 Hypotension by anesthesia is related to vasodilation and reduced inotropy, if
needed vasopressors can be used.
 Fluid therapy in high risk patients guided by
 invasive CVP monitoring for early recognition of overt hypovolemia and
 markers of global tissue perfusion, like lactate and acid-base status.

9.  In certain orthopedic and intraabdominal operations CO optimized by
titrating boluses of a suitable colloid
 Blood loss replaced with colloid or blood and blood products
depending on the volume lost.
 Crystalloid used as an alternative for intravascular plasma volume
expansion.
 Overall the goal is to achieve euvolemia by the end of surgery or the
early postop period.

10.  Postoperative
 Assessment of fluid status made based on
 clinical examination and
 lactate,
 central or mixed venous saturations, and
 cardiac output variables.
 If euvolemic then early oral intake is well tolerated and safe
 In patients requiring ongoing IV therapy in postop phase:
 1. Monitor for hyponatremia and other electrolyte derangements.
 2. Fluid requirements should be strictly divided into three categories:

11.  A. “Pure” maintenance requirements
(saltpoor, modest volume of free water to account for the postoperative state of salt and water
retention)
 • 1500 to 2500 mL or 1 to 1.2 mL/kg/hr of fluid with 50 to 100 mEq Na+ & 40 to 80 mEq K+
should be given in first 24 hours
 B. Replacement of ongoing losses
 Assessment of IV volume status and adequacy of organ perfusion.
 Losses from the GI tract replaced with isotonic saline or balanced crystalloid with K+.
 Losses to third spaces with a mixture of colloid and crystalloid
 Blood loss replaced with colloid, blood, or blood products, and definitive intervention.
 C. New requirements (resuscitation)
 Postop complications; hemorrhage (absolute hypovolemia) or acute sepsis (relative or
absolute hypovolaemia).
 Postop oliguria, particularly in the first postop 24 hours.
 Large volumes of fluid challenge are inappropriate and may aggravate postop positive fluid
and Na+ balance.

12. Special
Considerations/
Patient Factors

13. HEART FAILURE
 Goals => Preserve CO, preload, contractility, and afterload.
 Ventricles poorly compliant and require adequate preload and adequate diastolic
filling time.
 Excessive volume infusion and preload => Impaired contractility and worsening CO
 Invasive monitoring with either EDM/ PAC for fluid therapy
 Restrictive Fluid therapy or GDT is preferred.
 Striking a balance between hypovolemia and hypervolemia is particularly
important in patients with heart failure,

14. KIDNEY DISEASE
 Preop assessment should focus on
 the adequacy of chronic dialysis in attaining euvolemia, and
 estimating the normal volume of native urine output.
 Comorbidities should be assessed and optimized.
 Surgery undertaken in a facility where preop and postop dialysis or
hemofiltration done.
 In elective surgery, preop dialysis timed such that the patient enters
the intraop phase with a normal blood volume

15.  Hypervolemia => risk for pulmonary and peripheral edema, hypertension, and
poor wound healing.
 Hypovolemia => risk for anesthesia-related hypotension and inadequate tissue
perfusion.
 Dialysis the day prior to allow equilibration of fluid and electrolyte.
 Electrolytes on the morning of surgery ( ideal K+ value after dialysis is low-to-
normal range. )
 In emergency surgery, NO sufficient time for dialysis, electrolyte abnormalities
must be managed conservatively, intraop fluid balance.

16. UPPER GASTROINTESTINAL LOSS
 Progressive dehydration => Increased aldosterone secretion => Na+ is
retained at the expense of K+ and H+ ions, (hypokalemia, and
metabolic alkalosis with a paradoxically aciduria)
 Correction => Gradual rehydration with isotonic saline and K+
supplementation and changing to dextrose- containing saline
depending on electrolyte analysis.

17. SEPSIS AND ACUTE LUNG INJURY
 The pragmatic targets for patients with sepsis who have tissue
hypoperfusion (blood lactate conc. at or >4 mmol/L) or hypotension
persisting after Initial IV fluid Challenge:
 CVP 8 to 12 mm Hg (12 to 15 mm Hg in patients on Ventilation)
 MAP 65 mm Hg or greater
 Urine output 0.5 mL/kg/hr or greater
 ScvO2 > 70% (or mixed venous O2 saturation > 65%)

18.  Current recommendations to attain these goals
 30 mL/kg of suitable crystalloid
 Albumin along with vasopressors and inotropes
 RBC transfusion.
 Patients with established ARDS for surgical procedures.
 Focus of fluid therapy is the fine balance between avoiding an
increase in lung edema while maintaining adequate tissue
perfusion.
 Early goal-directed fluid therapy may prevent ALI/ARDS
 In established ALI/ARDS a fluid-conservative approach is the
minimum requirement

19. BURNS
 IV fluid therapy is generally instituted for burns of greater than 15%
total body surface area in adults and 10% total body surface area in
children
 Parkland Burn Fluid Resuscitation Formula
First 8 hours: 2 mL/kg × % TBSA (lactated Ringer solution)
Next 16 hours: 2 mL/kg × %TBSA (lactated Ringer solution)
Next 24 hours: 0.8 mL/kg × %TBSA (5% dextrose) + 0.015 mL/kg × %TBSA (5%
albumin)

20.  Down-titration of fluid volumes if UO is adequate (0.5 to 1 mL/kg/hr)
 Excessive fluid administration (“fluid creep”) may cause
 Pulmonary edema
 Fasciotomies in nonburned muscle compartments
 Raised IOP
 Conversion of superficial to deep burns
 Intraabdominal hypertension and compartment syndrome
 Haifa formula (New Practice)
 Plasma (cc) - 1.5 x % TBSA x body weight (kg) + RL (cc) - 1 x % TBSA x body weight
(kg).
 Half fluid in first 8 hr and the other half in the next 16 hr
 In the subsequent 24 hr, we give half the amount estimated for the first day.
 The sufficiency of the fluid is judged mainly on the basis of urine output.

21. HEPATIC FAILURE
 Progressive liver disease and cirrhosis cause
 peripheral vasodilation and
 relative intravascular depletion (total body Na+ and water are retained with
ascites and edema )
 Aim is reduction of total body salt and water
[dietary fluid and salt restriction, diuretics (spironolactone and loop diuretics),
and intermittent or continuous drainage of ascites]
 Excessive isotonic saline => salt and water overload=> further ascites
and edema formation.
 Approach => Assess volume status and replace losses with
appropriate volumes of isotonic crystalloid, colloid, or blood but avoid
salt and water overload.

22.  Large-volume (>6 L) ascites drainage => hemodynamic instability =>
Albumin is more effective than saline.
 Lactate and other buffered fluids may be used in hepatic failure,
although their metabolism may be slowed in advanced liver disease.
 In decompensated liver disease with encephalopathy, raised ICP may
be present and osmotherapy, such as hypertonic saline or mannitol
should be used to bring plasma Na+ into the high-normal range.
 In chronic compensated liver disease, a degree of hyponatremia is well
tolerated and does not require acute correction.

23. OBSTETRICS
PIH & PREECLAMPSIA
 A clear association between positive fluid balance and the incidence of
pulmonary edema in this condition
 Restricted volumes of IV crystalloid (80 mL/hr), and fluid balance observed
carefully.
 Oliguria not treated by administration of large volumes of fluids if kidneys
normal .
 Blood loss replaced with an appropriate volume of crystalloid, colloid, or
blood, depending on magnitude.
 Invasive monitoring can be used to direct fluid therapy in severe
preeclampsia.

24. GERIATRIC:
 Decrease in TBW, GFR, urinary concentrating ability, aldosterone, thirst mechanism, free-water
clearance.
 Increase in antidiuretic hormone (ADH), atrial natriuretic peptide (ANP)
 Renal capacity to conserve sodium is decreased.
 Tendency to lose sodium in the setting of inadequate salt intake.
 Decreased thirst response => risk for dehydration and sodium depletion.
 Diminished ability to respond to an increased salt load => increased Na+ retention during the
periop period.
 Volume expansion SHOULD BE DONE CAREFULLY
 BLOOD BY BLOOD in periop settings.

25. PEDIATRICS
 Holliday and Segar in 1957=> 4-2-1 volume calculation for maintenance fluid
requirements for
 insensible losses and
 urinary losses
 Glucose-based solutions intraop to reduce high risk for preop hypoglycemia after
prolonged fasting and
 Postop maintenance fluids based on the 4-2-1 calculation using hypotonic
crystalloids.
 Paeds population considered at risk for preop dehydration by fasting (limited urinary
concentrating ability and ongoing insensible losses because of large body surface
area.)
 Intraop replenishment of these volumes using isotonic salt solution

26. Re-evaluation
 Longer preop fasting discouraged carbohydrate-containing—fluids up to 2 hours before
surgery.
 Preop hypoglycemia incidence is infrequent (<2.5%) & related to
 inappropriately prolonged fasting
 premature infants,
 neonates who are SGA, or
 those with poor nutritional status.
 Surgery + Glucose-containing solutions => hyperglycemia => Complications
 osmotic diuresis
 electrolyte abnormalities => adverse neurologic outcomes (ischemia or hypoxia)
 Glucose-free balanced crystalloid solutions should be used intraop, except in those at
particularly high risk for hypoglycemia.
 Surgical stress and presence of pain and hypovolemia => SIADH => water retention and
hypoosmolar hyponatremia with hypotonic solutions in significant volumes.

27.  Proposed strategies to avoid this
 Using half to two thirds of calculated 4-2-1 formula maintenance fluids,
 Avoiding the hypotonic fluids (4% dextrose with 0.18% NaCl)
 Returning to oral fluids as early as possible
 Ensuring euvolemia to minimize the ADH response
 Not confusing maintenance requirements with ongoing losses (e.g., GI or blood),
which should be replaced by isotonic crystalloids, colloids, or blood
 Checking electrolytes at least daily in those still receiving IV fluids.
 Isotonic saline “safer” for postop maintenance, but risk of Na+ overload and
hyperchloremic acidosis.
 Dearth of data on colloid volume expansion and goal-directed fluid therapy.

28. FLUID THERAPY IN IMPORTANT
MAJOR SURGERIES/
SURGICAL FACTORS

29. NEUROSURGERY
 Rational management =>
 maintain baseline blood volume and cerebral perfusion
 avoid decreases in serum Na+, osmolality, and oncotic pressure.
 Specific management may be required in:
 1. Increased ICP:
 Mannitol and hypertonic saline given by bolus.
 Hypertonic saline superior to mannitol.
 Restrictive fluid strategies advocated in severe traumatic brain injury.
 2. Cerebral vasospasm: “triple-H” therapy
 Hypervolemia, Hemodilution, Hypertension
 3. Intacranial pathologic condition CAUSE cerebral salt wasting, diabetes insipidus,
SIADH.
 Albumin is => increase in mortality in traumatic brain injury.

30. TRAUMA
 Goal=> Hemostasis then restoration of normal circulating volume and tissue perfusion
 Permit hypovolemia to achieve cerebration rather than normotension, maintain SBP of
 70 to 80 mm Hg in penetrating trauma, or
 90 mm Hg in blunt trauma.
 Rapid radiologic or surgical damage control intervention.
 Large volumes of IV crystalloids or colloids in early resuscitation will cause hemodilution and dilute
clotting factors, and saline-based fluids may aggravate the acidosis .
 pRBCs, FFP and platelets replaced early. “High” ratios of FFP to pRBC (e.g., 1:1 to 1:2) are
associated with the best outcomes
 Avoidance hyponatremia and hypoosmolality to minimize cerebral edema in isolated head
injuries with a MAP >90 mm Hg.

31. FREE TISSUE FLAP SURGERY
 Flap blood flow depends on
 systemic blood pressure
 blood viscosity
 Hypervolemic hemodilution has traditionally been used
 Conservative fluid strategy improves flap outcome by avoiding
reduction in O2 carrying capacity and potential for flap edema
 Large volumes of crystalloid — favoring increased capillary filtration —
AVOIDED and colloids used for blood volume expansion.

32. INTRATHORACIC PROCEDURES
 Any procedure within the thorax can lead to postoperative respiratory
problems, including ARDS and acute lung injury (ALI).
 There are reduced pulmonary complications with restrictive fluid
strategies.
 The use of diuretics to actively target fluid balance, degree of
cardiovascular support, and presence or of epidurals helps
 Improved pulmonary outcomes in those treated with a restrictive
rather than liberal fluid regimen.
 Cautious approach to fluid administration is recommended, both to
minimize pulmonary complications and to avoid anastomotic edema.

33. MAJOR INTRAABDOMINAL SURGERY
 Fluid losses during surgery are caused by
 prolonged peritoneal exposure,
 significant blood loss, and
 acute drainage of tumor-related ascites.
 Difficult to quantify, so cardiac output monitoring, CVP, arterial pressure monitoring
and serial blood gas analysis is valuable.
 Intraoperative drainage of ascites may require large volumes to replace the ongoing
loss.
 Consequence of fluid redistribution is electrolyte abnormalities; e.g. hypokalemia
and hypomagnesemia .

34. RENAL TRANSPLANT
 The key goals are
 ensure adequate renal perfusion to support early graft function
 avoid fluid therapy side effects
 CVP-guided intraop fluid therapy, large volumes of crystalloid (up to 60 to 100 mL/kg) to achieve
CVP of 10-12 mm Hg or higher before reperfusion.
 Recently, more conservative goals, like crystalloids at15 mL/kg/hr or more, for CVP of 7-9 mm
Hg with no increase in graft failure.
 Balanced crystalloid solutions or K+ free buffered dialysate solutions used.
 The role of colloids not clear(concerns over renal toxicity of starches).
 Postop fluid therapy should aim baseline requirements and the ongoing losses resulting from
urine production.

35. LIVER TRANSPLANT
 Guided by invasive monitoring like pulmonary artery catheterization.
 During phase I (preanhepatic), large-volume blood loss and fluid shift resulting from
drainage of ascites.
 During phase II (anhepatic) a major reduction in venous return and CO if the IVC,
portal vein, and hepatic artery are cross-clamped. Crystalloid and colloid infusion
required with vasopressors to maintain arterial pressure.
 Phase III (reperfusion) acute rise in CVP, hepatic congestion and right heart strain.
Systemic vasodilation and cardiac suppression leads to hypotension requiring
vasopressor or inotrope. Fluids should be restricted
 Ongoing infusion of fluids, red cells, and blood products should be guided by clinical
blood loss, maintaining a hematocrit of 26% to 32% .

36. TRANSFUSION THERAPY
- 60% of transfusions occur perioperatively.
- responsibility of transfusing perioperatively is with the anesthesiologist.
WHEN IS TRANSFUSION NECESSARY?
 “Transfusion Trigger”: Hgb level at which transfusion should be
given.
 Varies with patients and procedures

37. LIBERAL VERSUS RESTRICTIVE TRANSFUSION STRATEGY
 Restrictive policy = BT only when the Hb value is 7 to 8 g/dL or less.
 Liberal policy = BT when the Hb value is 9 to 10 g/dL or greater.
 If no clinical advantages with the liberal transfusion policy, perhaps the restrictive
approach should be used.

38. PERIOPERATIVE FLUID
THERAPY IS A MAJOR
TASK!!
ANTICIPATION OF COMPLICATIONS HELPS
!!

39. THANKS! ANY QUESTIONS?