1. 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.
2. 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)
4. 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,
5. 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
6. 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.
7. 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.
8. 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%)
9. Current recommendations to attain these goals
⚫ 30 mL/kg of suitable crystalloid
⚫ Albumin along with vasopressors and inotropes
⚫ RBC transfusion.
Patients with establishedARDS 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
10. 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)
11. 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.
12. 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.
13. 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.
14. 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.
15. 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
16. 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.
17. 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.
19. 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.
20. 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.
21. 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 .
22. 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% .
23. 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.
