5. Normal water balance
• Insensible fluid input - 300ml due to oxidation.
• Insensible fluid loss – 500ml (skin), 400ml
(lungs), 100ml (stools)
• Normal daily insensible fluid loss- 1000-
300=700ml.
• Daily fluid requirement = UO+ insensible
losses.
• Abnormal fluid loss- sweating, exercise, high
fever, burns, exposed body cavity(surgery)
6. Distribution of electrolytes
ECF ICF
Major Cation Sodium Potassium, Magnesium
Major Anion Chloride, Bicarbonate Phosphate, Sulphate, Protein
7. Physics related to fluid kinetics
• Osmosis: – Fluid movement from low solute
(High solvent, Dilute) solution to high solute
(Low solvent, concentrated) solution
• Two solutions of varying solute concentrate
separated by semipermeable membrane
• Osmotic pressure – minimum pressure
needed to be applied to prevent inward flow
of solvent across semipermeable membrane
8.
9. Osmolality and Osmolarity
• Osmolality - Molality is the number of moles present in 1 kg of
solvent.
• Normal body osmolality is 285 to 290 mOsm/kg and is the same in
intracellular and extracellular compartments because of the free
movement of water between compartments that consequently
prevents the development of any osmotic gradients.
• The largest contribution to plasma osmolality is made by sodium and
its related anions chloride and bicarbonate. It can be estimated by:
• Serum osmolality= (2×Na) + (glucose÷18) ) + (urea ÷ 2.8)
• OSMOLARITY is the number of osmoles of solute per liter of solution;
unlike osmolality, this may be affected by temperature changes as a
result of the volume- expanding effect of increasing temperature.
10. • TONICITY -This is the effective osmolality of a solution with
respect to a particular semipermeable membrane and takes into
account solutes that do not exert an in vivo osmotic effect.
• For example, Na+ and Cl− do not cross cell membranes freely and
therefore exert an effective osmotic force across these
membranes, whereas urea freely diffuses across cell membranes
and therefore does not exert an osmotic effect here. Similarly,
glucose is normally taken into cells by insulin- stimulated
facilitated diffusion, so it is an ineffective osmole.
• It can be estimated by subtracting urea and glucose
concentrations from measured osmolality.
• An infusion fluid is “ISOTONIC” if its calculated in vivo
osmolality ranges between 280 and 300 mOsmol/ kg.”
12. CRYSTALLOIDS
• Crystalloids are solutions of electrolytes in water.
• They are indicated for replacement of free water and
electrolytes but may be used for volume expansion.
• Crystalloids get distributed throughout the entire ECF with
only 20% remaining in the intravascular compartment.
• Patients resuscitated with crystalloids have a more positive
fluid balance for the same volume expansion effect.
• Tissue oedema may increase in compliant tissues such as
lung , gut and soft tissues especially in normovolemic
subjects.
• Its large volume can cause hypercoaguable state by diluting
circulating anticoagulant factors.
13. Isotonic Normal Saline
• Contains sodium 154 meq and chloride 154
meq
• Distributed chiefly in extra cellular fluid
• Increases the intravascular volume
substantially
• Therefore isotonic saline is a most commonly
used i.v. fluid to raise blood pressure in a
patient with hypovolemic shock
14. HYPERTONIC SALINE
• Solutions of 1.8%, 3% and 7.5% NaCl are
available
Their uses include:
• Plasma volume expansion
• Correction of hypo osmolar hyponatraemia.
• Treatment of increased intracranial pressure.
15. RINGER’s LACTATE
• RL substitute a portion of chloride content with L-lactate buffer,
providing a more physiologic chloride concentration.
• It is slightly hypotonic relative to plasma and may worsen cerebral
oedema and increase in intracranial pressure in patients with head
injury.
• Ringer’s lactate may not be a choice in patients with liver
hypoperfusion or insufficiency since lactate metabolism entirely
depends on preserved liver function.
• To compensate this ,L- lactate is replaced with acetate , is rapidly
oxidized by the liver , muscle and heart to give HCO3-
16. Balanced salt solutions
• They are more closely matched to physiologic plasma
composition than NaCl solutions and contain 134mEq/L
Na+ , 118mEq/L Cl- and 16 mEq/L HCO3-
• They contain stable organic anionic buffers such as
lactate , gluconate or acetate to compensate the
reduction in anionic content .
• The excretion of the excess water and electrolyte load
with balanced crystalloids is more rapid than with
isotonic saline.
• Large doses of D-Lactate may be associated with
encephalopathy and cardiac toxicity and lactated
solutions should be avoided in severe liver failure.
17. Plasmalyte- A
• Plasma-Lyte is closest to balanced both acid-base and
tonicity perspectives.
• It contains stable organic anionic buffers of acetate and
gluconate.
• Plasma-Lyte does not contain Calcium and thus is used
for dilution of Packed red blood cells prior to
transfusion.
• It may be the best option for patients with diabetic
ketoacidosis in which correction of severe metabolic
acidosis and fluid intervention is indicated.
18. DEXTROSE SOLUTION
• It has two main indications in the perioperative setting:
• As a source of free water
• Source of metabolic substrate
• Dextrose solutions are hypotonic free water with respect
to cell membrane as soon after administration , the
dextrose is taken up into cells in the presence of insulin
leaving behind Free water.
• Therefore carefully used in patients of SIADH.
• Contraindicated in neurosurgery as can lead to cerebral
oedema being hypotonic in nature
19. CRYSTALLOIDS
• ADVANTAGE
• Are inexpensive and non
allergic
• More effective at
replacing depleted ECF .
• Not associated with
transmission of infection
, impairment of
coagulation or cross
matching.
• DISADVANTAGE
• They exert short lived
hemodynamic effects in
comparison to colloids.
• In massive fluid
resuscitation ,they can
produce peripheral
oedema and occasionally
pulmonary edema.
20. COLLOIDS
• It is defined as large molecules or ultramicroscopic particles of
a homogenous non crystalline substance dispersed in a second
substance , typically isotonic saline , or a balanced crystalloid.
• We have:
• Semisynthetic colloids
• Human plasma derivative
• They are potential intravascular plasma volume expanders
because they have minimum transcapillary filtration power.
• But the introduction of a large quantities of semisynthetic
molecules(40-60g/L) may cause undesired effects on immune ,
coagulation and renal system.
23. GELATIN
• Gelatin is a large molecular weight protein formed from hydrolysis of
collagen.
• It is sterile, pyrogen free, contains no preservatives and has a
recommended shelf-life of 3 years when stored at temperatures less
than 30°C
• There are 3 types of gelatin solutions currently in use in the world:
• Succinylated or modified fluid gelatins (e.g., Gelofusine, Plasmagel,
Plasmion)
• Urea-crosslinked gelatins (e.g., Polygeline or Haemaccel)
• Oxypolygelatins (e.g., Gelifundol)
24. INDICATIONS
• Hypovolemia due to acute blood loss.
• Acute normovolumic haemodilution
• Extracorporeal circulation – cardiopulmonary
by-pass
ADVANTAGE
• Cost effective
• No limit of infusion.
• No effect on renal impairment.
25. Disadvantage
• Anaphylactoid reactions: Gelatins are associated with
higher incidence of anaphylactoid reactions as compared
to natural colloid albumin.
• Effect on coagulation: The effect of gelatins on
coagulation is not clear. There are studies which support
activation of coagulation by gelatins and there are some
studies which reveal increased bleeding time, impaired
platelet adhesiveness during cardiac surgery.
26. HES (HYDROXYETHYL STARCH)
• HES solutions are most commonly used colloids worldwide.
• However , high molecular weight preparations(eg;
hetastarch , pentastarch) were associated with coagulopathy
and AKI in sepsis , resulting in their disuse.
• Third generation HES (tetrastarch) has reduced
concentration (6%)with a molecular weight of 130 kDa and
these solutions have been used to optimize hemodynamics
in critical care patients and in individuals undergoing major
surgery, particularly as a component of goal directed
therapy to prevent excessive positive fluid balance.
27. DEXTRAN
• Dextrans are highly branched polysaccharide molecules
which are available for use as an artificial colloid.
• They are produced by synthesis using the bacterial enzyme
dextran sucrase from the bacterium Leuconostoc
mesenteroides (B512 strain) which is growing in a sucrose
medium.
• Two dextran solutions are now most widely used:
• A 6% solution with an average molecular weight of 70,000
(dextran 70) & colloid osmotic pressure of about 40 mm Hg.
• A 10% solution with an average weight of 40,000 (dextran
40, low-molecular-weight dextran)
28. USES
• Volume expansion: Dextrans leads to 100–
150% increase in intravascular volume.
• Microcirculation: Dextran helps in improving
microcirculatory flow by two mechanisms, i.e.,
by decreasing the viscosity of blood by
haemodilution and by inhibiting erythrocytic
aggregation.
29. HUMAN PLASMA DERIVATIVES
•It include;
•Human albumin solutions
•Plasma protein fractions
•Immunoglobulin solutions
30. ALBUMIN
• Human serum albumin (HSA) is the most abundant circulating protein in
the body provided of both oncotic and non-oncotic properties
• HSA is the main circulating protein in healthy individuals (3.5–5 g/dl),
representing about 50% of the total protein content in the plasma.
• Available as 5%, 20% and 25%
• A 5% albumin solution (50 g/L or 5 g/dl) has a colloid osmotic pressure of
20 mm of Hg (which is similar to that of plasma), and expands the plasma
volume to roughly the same as volume infused.
• Approximately half of the infused volume of 5% albumin stays in the
vascular space.
• The oncotic effects of albumin last 12 to 18 hrs.
31. • 25% albumin solution has a COP of 70 mm of Hg and
expands the plasma volume by 4 to 5 times the volume
infused.
• Thus infusion of 100 ml of 25% albumin can increase
the plasma volume 400-500 ml.
• This plasma volume expansion occurs at the expense
of the interstitial fluid volume (fluid shifts from
extravascular to intravascular compartment ) so 25%
albumin should not be used for volume resuscitation in
patient with fluid deficit (hypovolemia).
32. FUNCTIONS
• Oncotic properties :
• Accounts for about 70–80% of the plasma oncotic
pressure
• Non-oncotic properties :
• HSA binds and carries a great variety of
hydrophobic molecules, such as endogenous (i.e.,
cholesterol, fatty acids, bilirubin, thyroxine) or
exogenous substances (i.e., drugs), transition metal
ions, and gas (nitric oxide [NO]), with consequent
implications on their solublization, transport and
metabolism
33. COLLOIDS
• ADVANTAGE
• They preferentially expand
plasma volume rather than
interstitial fluid volume
which may result in lower
fluid requirement and less
peripheral and pulmonary
oedema.
• DISADVANTAGE
• Greater expense
• Allergic reactions(gelatin)
• Infection risk(HAS)
• Coagulopathy (dextrans
and starches)
• Impaired cross matching
(dextrans)
• Reduction in ionised
calcium
34. WHY FLUIDS?
• Pre-op
• less intake of fluids prior to fasting
• Prolonged fasting time
• Bowel preparation
• Intra-op
• Direct blood loss
• Insensible losses –
• Exposure of large internal surfaces
• Dry gases while intubated
• The inflammatory response elicited by tissue trauma may be
aggravated by periods of hypotension and tissue
hypoperfusion
35.
36. “Zero-Balance” approach
• “Zero-balance” simply replaces what is lost (e.g.,
insensible loss through ventilation and respiration, or
volume loss from intraoperative hemorrhage)
• Avoiding dehydration and hypovolemia or fluid overload
with their associated complications
• The terminologies “liberal fluid therapy” and “restrictive
fluid therapy” are not in use now, due to the
misinterpretations and associated complications
• The American Society for Enhanced Recovery (ASER)
has also adopted “zero-balance” for perioperative fluid
management*
37. Goal directed fluid therapy
• The practice of GDT is based on measuring key
physiologic variables related to cardiac output or global
O2 delivery and administering fluids, and possibly
inotropes, vasopressors, vasodilators, and RBCs to
improved tissue perfusion and clinical outcome.
• Here fluid administration is a continuous dynamic
process that targets defined physiologic endpoints rather
than giving fluids without objective assessments of fluid
status
38. Pre-operative assessment for fluid
deficit
• history of intake and
output
• NPO status and time
• Blood pressure : supine
and standing
• Heart rate
• Skin turgor, mucosa
• Urinary output
• CVP
• Serum
electrolytes/osmolarity
Signs of hypovolemia
• Heart rate > 90 (or 20% >
baseline)
• SBP < 90 (or 20% <
baseline)
• Urine output of less than
0.5 ml/kg/h
• High lactate
• Low central venous
pressure (CVP)
(not reliable in anesthetized
patient)
39. Intraoperative fluid strategy
2 main ways:
❑ by estimating the requirements based on patient
weight, NPO deficit, nature and quantity of losses
❑ by direct measurement of an individual’s physiologic
variables and administering fluid to achieve an
improvement in these physiologic variables, i.e. goal-
directed therapy
40. NPO Guidelines
Patients should be encouraged to
continue PO hydration up until 2 h
before surgery, simply to optimize
the volume status
Carbohydrate drinks during fasting
- Keeps patient in anabolic state.
- decreases overall discomfort in the
preoperative and postoperative
period.
- Decrease postoperative insulin
resistance through increasing
insulin activity
41. Intraoperative fluid strategy
• Intraoperative fluid requirements
- volume therapy
- maintenance therapy
• Insensible losses (e.g., perspiration or urine output)
will make up a very small percentage of ongoing loss,
that require maintenance therapy
• Current evidence suggest maintenance requirements -
basal crystalloid infusion rate of 1 to 1.5 ml/kg/hr.
• More is needed for major surgeries (large fluid shifts)
42. Intraoperative fluid strategy
Volume therapy -
● Administration of boluses of IV fluid (typically
250 ml) to assess volume responsiveness and
treat hypovolemia , with the goal of improving
intravascular volume and oxygen delivery
● The overall goal of fluid management for major
surgery should now be considered to be a
moderately liberal approach, with a positive
fluid balance at the end of surgery of 1 to 2 L.
44. Intraoperative fluid strategy
Deficits
• Preop npo (hrly maintenance x duration)
• Preop blood loss (trauma) or
• fluid loss(bowel preparation – up to 1 ltr)
• Replace ½ FIRST Hour, 1/4 2ND hour, 1/4 3RD
Hour
45. Intraoperative fluid strategy
Third space losses
• Isotonic transfer of ECF from functional body fluid
compartments to non-functional compartments
• Peritoneal cavity- ASCITES
• Pleural cavity- effusion
• Swelling of tissues after surgical trauma
• Depends on:
-location and duration of surgical procedure
-amount of tissue trauma
-ambient temperature
-room ventilation
46. Intraoperative fluid strategy
REPLACEMENT OF THIRD SPACE LOSS
• Superficial surgical trauma:1-2ml/kg/hr
• Minimal surgical trauma:3-4ml/kg/hr
head and neck surgery, hernia, knee surgery
• Moderate surgical trauma:5-6ml/kg/hr
hysterectomy, chest surgery
• Severe surgical trauma:8-10ml/kg/hr
AAA repair, nephrectomy
47. Intraoperative fluid strategy
DRAWBACKS OF 4-2-1 rule
• Overestimation of energy expenditure
• Fluid overload due to overestimation of
insensible loss
• Underestimates sodium requirement so increase
risk of hyponatremia.
49. Paediatric patient
• Needs special consideration. Why?
1. Greater insensible losses
2. Greater urinary loss
3. Immature thirst mechanism
4. Fluid overload(smaller circulatory volume)
5. Volume and distribution of body water
50. PERIOPERATIVE FLUID MANAGEMENT
IN NEONATES
• On the basis of tradition the perioperative use of hypotonic
electrolyte or electrolyte free glucose containing solutions
is common during neonatal surgery
• In neonates the combined effects of perioperative
hypotonic fluids and ADH on water reabsorption in kidney
may lead to decrease in plasma sodium concentration
• Some authors concluded in their studies that routine use of
hypotonic electrolyte solutions during neonatal surgery
should be questioned
• In an another observational study, the intraoperative
infusion of 10ml/kg/h of balanced isotonic solution with
glucose 1% was associated with stable sodium and glucose
concentrations in neonates
51. PERIOPERATIVE FLUID MANAGEMENT
IN NEONATES
• Dutta et al compared the effects of an intraoperative
infusions of 10 ml/kg/h of glucose 1% and 2% in ringer
lactate in neonates with low birth weight of 1.6-2.8 kg
• They found that the studied solutions were equally
effective in maintaining glucose homeostasis but that the
glucose solution with higher concentration inhibited
catabolism ,insulin resistance ,rebound hyperglycaemia and
acidosis
• Special care must be taken when administering electrolyte
free concentrated glucose solution : accidental
hyperperfusion may result in deleterious incidents like
hyperosmolar hyperglycaemic coma
52. SALINE 0.9% AND HYPERCHLORAEMIC
ACIDOSIS
• Saline 0 .9% avoids the risk of hyponatremia ,but it contains
too much chloride and no bicarbonate precursor
• Infusion of high volumes may cause chloride overload
leading to a suppression of renal blood flow and RAAS and
hyperchloraemic acidosis
• In a study with accidental hyper perfusion /
hyperchloraemic acidosis develop with saline 0.9% and
acid-base parameters remained more stable with balanced
isotonic electrolyte solution
• With the concept of homeostasis in mind the composition
of saline 0.9% is definitely non physiological and balanced
isotonic elec. solution should be preferred because of their
resemblance to extracellular fluid
55. CONCLUSION
• Perioperative fluid management in children should be
based on physiology and focused on the maintenance of
the patient homeostasis
• Optimised preoperative and postoperative fasting times are
important to avoid patient discomfort ,iatrogenic
dehydration and catabolic state
• Balanced isotonic electrolyte solutions are recommended
for fluid replacement in all age groups to avoid both
hyponatremia and hyperchloremic acidosis
• For intraoperative maintenance infusion ,addition of 1-2%
glucose is recommended to avoid hypoglycaemia ,lipolysis
or hyperglycaemia
• Modified fluid gelatine or HES in balanced elect sol can
safely used to quickly normalise blood volume in case of
perioperative circulatory instability and blood loss.
56. DIABETIC KETOACIDOSIS
• Fluid and Electrolyte loss
• Hyperglycaemia in DKA leads to glycosuria which further
leads to osmotic diuresis. So large amount of water and
electrolytes are lost.
• Hyperglycaemia induced hyper osmolality causes the
movement of water out of cell with subsequent
intracellular dehydration, extracellular fluid expansion
and diuresis.
• Results in diminished urine flow and greater retension of
glucose in plasma.
• Vomiting aggravates hypovolemia.
57. • Metabolic Acidosis
• In DKA, fat is mobilized at an excessive rate to supply
energy formation of ketone bodies.
• These keto acids are neutralized by bicarbonate buffer,
thus bicarbonate levels decreases leading to metabolic
acidosis. Severe dehydration induced hypoperfusion
leads to impaired renal function which further
contributes to metabolic acidosis.
• Potassium Imbalance
• Metabolic acidosis and lack of insulin results in
extracellular shift of potassium
• Osmotic diuresis leads to loss of potassium in urine.
• Lost in vomiting also.
• So in DKA, Sr. potassium may be high, normal or even
low but there will be deficit of total body potassium.
58. LOSSES IN DKA
• WATER - 5-8 litres or 100ml/kg BW
• SODIUM- 400-700mEq or 7-10 mEq/kg BW
• POTASSIUM- 250-700 mEq or 3-5 mEq/kg BW
• This loss represents loss of water in excess of loss of
sodium and therefore, fluid lost in DKA more closely
resembles hypotonic saline solution rather than
isotonic solution.
• SO INITIAL TREATMENT PRIORITY IS RESTORATION OF
FLUID DEFICIT WITH PROPER FLUID.
59. • WHICH FLUID?
• Initially glucose free fluids.
• In shock isotonic saline is preferred.
• Ringer’s lactate is given in the absence of shock,
hypotension and in Pt with good UO.
• After initial fluid replacement , depending upon
serum sodium, fluid should be changed to 0.45%
saline. This allows more free water to be delivered.
• At later stage(glucose levels-<250mg/dl)-dextrose
containing fluids should be given.
60. • How much fluid?
• 5-8 litres or 100 ml/kg BW.
• Fluid resuscitation should be started early and
continued till the resolution of ketoacidosis.
• Maintanence requirement
• After rapid fluid replacement OR in Pt’s with
insignificant fluid deficit. Fluids should be
administered slowly.
• 500ml/hr for first 4 hrs f/b 250 ml/hr.
61. • When and why dextrose solution is given?
• Started once blood glucose levels falls below
250 mg/dl.
For better intracellular distribution of free
water.
To prevent hypoglycaemia and to help in
resolution of the ketone bodies.
As a prophylactic measure to prevent late
cerebral oedema.
62. BURNS
• Extensive loss of fluid due to
Loss of endothelial barrier function
Increased capillary permeability and filteration
Evaporative transcutaneous fluid loss
63. • Fluids: when?
• Burns >15% of total body surface area in adults
• >10% of TBSA in children
• HOW?
• PARKLAND FORMULA : includes body weight and extent
of burns.
• First 8 h: 2ml/kg/%TBSA(RL)
• Next 16 h: 2ml/kg/%TBSA(RL)
• Next 24 h : 0.8ml/kg * %TBSA (5%dextrose) + 0.015ml/kg
* %TBSA(5% albumin)
64. Underhydration
• Loss of Zone of Pnumbra
• Organ hypoperfusion
• Increase in depth of burns
• Hypovolemic shock
Overhydration
• Pulmonary oedema
• Compartment syndromes
• Raised ICP
• Conversion of superficial
burns to deep
• Third spacing
65. Obstretic preeclampsia
• Multisystem ds characterized by hypertension, proteinuria
and multiorgan involvement (kidneys,liver,lungs,CNS)
• In contrast to usual volume expanded status in pregnancy,
pt with pre eclampsia have reduced plasma volume
combined with endothelial dysfunction and
hypoalbuminemia.
• Acute pulmonary oedema – 5-30% of cases and is leading
cause of morbidity and mortality in pre eclamptic pts.
• Autotransfusion into vasoconstricted circulation after
delivery and low oncotic pressure further contributes to
pulmonary congestion.
66. • Pre eclamptic pts should receive volumes of IV
crystalloid (80 ml/h, including that received as
drug diluent)
• Fluid balanced to be observed carefully.
• Oliguria should not be treated with large volumes
of fluids in the presence of normal kidney
functions
• Any blood loss should be replaced by appropriate
volume of crystalloid, colloid or blood.
• Invasive monitoring should be used to direct fluid
therapy in cases of severe pre eclampsia.
