Intravenous Fluids

Presented by: Dr. Meenal Aggarwal

Moderator: Dr. S. Singh

Basic Physiology

• Total body water:

Pre mature infant : 80% of lean B.W.

Term infant: 70 – 75%

Adult male : 60% (more muscle)

Adult female : 50% (more fat)

TBW(60) : ECF (20)(plasma + interstitial fluid) + ICF (40)

40

515

40 ICFPlasmaInterstitial fluidRest of B.W.

• In children : higher ECF (contributes to higher B.W.)

• T.B.W decreases with age (mainly d/t loss in ICF)

• Composition of body fluids:

ICF : K+ , Mg2+ Organic phosphate esters (ATP, Creatine

phosphate, phospholipids)

ECF : Na+ , Cl- , HCO3-

• Compartments are separated by semi-permeable membrane

• Water freely passes through it and maintains an osmotic

equilibrium

• Daily fluid requirement: Urine output + insensible losses (700ml)

Fluid Homeostasis in Body

Fluid Homeostasis in Body cont…

Normal Plasma Osmolality = 2 X [Na+] + [BUN/2.8] + [Glu/18]

Normal value = 275-295 mosm/Kg

Fluid Balance in Perioperative Period

• Goal: Euvolemia, normal oxygen carrying capacity and

normal electrolyte distribution

• Challenges: because of:

Fasting status

Losses (bleeding, evaporation, 3rd space losses)

Effects of neuraxial anesthesia (sympatholysis)

Ineffective thirst (d/t diminished alertness after GA/

sedation)

Assessment of Fluid Balance

• Preop History: Medical illness, preop vol status

• Surgery/ Intervention: Type of surgery, blood loss/ 3rd space

• Anaesthesia: Type, duration, Fluid replacement given, BT, Type

of monitoring, intra-op vital trends

• Current clinical condition:

GPE: Weight, Skin and tongue, sensorium, pulse, BP

Urine output : Should be >0.5-1ml/kg/hr

Monitoring: Pleth, IBP, C.O. measurement, CVP, PCWP, TEE

Lab: S.urea, S.creat, urinary Na, ABG (pH, lactate, Hct), VBG

Intra Venous FluidsI V Fluids

Crystalloids

Unbalanced

NS, 3% S, N/2 S

D5, D10, D 25

Balanced

Ringer Lactate

Isolyte P

Colloids

Gelatins

Dextrans

Starches (HES)

Human Albumin

Normal Saline (0.9% NaCl)

• Composition : Na+ 154 meq/L, Cl- 154 meq/L

• Osmolarity: 308 mOsm/L (Isotonic), pH : 6.0

• Distributed mainly in ECF, so very useful in hypovolemic shock

• Only 25% of the total fluid given remains intravascularly, 3-4 times

volume of fluid lost is required for replenishment

• Indication:

Salt and water deplation as in diarrhoea, vomiting, excessive

sweating

Tt of alkalosis (e.g. vomiting) with dehydration, May induce non

anion gap hyperchloremic metabolic acidosis (as high chloride l/t

dec plasma HCO3- content)

Normal Saline (0.9% NaCl) cont..

Hypovolemic shock

Hyponatremia

Initial fluid therapy in DKA

Fluid challenge in pre-renal ARF

Irrigation fluid

Hypertonic Saline (3-7.5%): used in therapy of severe

symptomatic hyponatremia, for resuscitation in patients of

hypovolemic shock

Caution: should be administered slowly, preferably through

central venous catheter because can l/t hemolysis

Normal Saline (0.9% NaCl) cont..

• Contraindication:

Cautious use in HTN or preeclamptic patients, CHF pts, renal

ds, cirrhosis

If dehydration is preset along with hypokalemia (need to add

K+ or else NS alone will aggravate K+ deficiency)

Used cautiously in patients with renal derangements (chloride

l/t decreased renal blood flow)

Note: As it can l/t metabolic acidosis, should not be mistakenly

interpreted as lactic acidosis in cases of impaired circulation

5% Dextrose

• Composition : Glucose 50 g/L (or 25 g/vac)

• Osmolarity: 252 mOsm/L (hypotonic), pH : 4.5

• Only 8% of the total fluid given remains intravascularly (glucose gets

metabolised when enters body, so free water) best for correcting

intracellular dehydration

• Provides 170 Kcal/ L

• Indications:

Tt of dehydration d/t inadequate water intake/ excessive water

loss

To provide calories

Pre- and post-op replacement fluid

5% Dextrose cont…

Tt and prevention of ketosis in starvation/ diarrhoea/ vomiting

Correction of hypernatremia ( with frusemide)

• Contraindications:

Cerebral edema/ Neurosurgical procedures/ Acute ischemic

stroke

Hypovolemic shock (also osmotic diuresis)

Careful administration during hypernatremia

Along with blood transfusion (hemolysis, clumping)

Severe hyperglycemia/ uncontrolled DM

Ringer’s Lactate

• Composition : Na= 130mEq, K= 4mEq, Ca= 3mEq, Cl= 109mEq,

lactate= 28 mEq per litre of RL

• Osmolarity: 274 mOsm/L (hypotonic), pH : 6.5

• Most physiological fluid (can be given in large quantities without risk

of electrolyte imbalance)

• Lactate is converted to HCO3 in the liver (correction of metabolic

acidosis)

• Indications:

Tt of severe hypovolemia rapidly with large fluid volume

Diarrhoea induced hypovolemia with hypokalemic metabolic

acidosis

Ringer’s Lactate cont… Postoperative fluid replacement

In DKA, RL provides free water so corrects metabolic acidosis, also

gives K (controvertial regarding lactate)

• Contraindications:

Liver ds, severe hypoxia and shock (impaired lactate metabolism)

In severe CHF with lactic acidosis

Addison’s disease

Even in severe metabolic acidosis (impaired lactate conversion)

In vomiting or NG aspiration (metabolic alkalosis, RL worsens)

Along with BT (Ca combines with citrate, forms clots), binds drugs

(thiopentone, amphotericin, ampicillin, EACA)

Isolyte-P

• Composition : Glu= 50 g, Na= 25mEq, K= 20mEq, Cl= 22mEq,

acetate= 23 mEq HPO4= 3 mEq, Mg= 3mEq per litre

• Designed to suit maintenance requirement of children (need more

water)

• Can be used In adults where more water required (hypernatremia)

• Indications:

Maintenance fluid in children and infants

Excessive water loss/ inability to conc urine (DI)

• C/I:

Hyponatremia, hypovolemic shock (less Na, More K, glucosuria)

Renal failure

Plasma-lyte

• Composition : Na= 140 mEq, K= 5 mEq, Cl= 98 mEq, acetate= 27

mmol, gluconate 23 mmol, Mg= 1.5 mmol per litre

• Produces a metabolic alkalinizing effect (acetate and gluconate

metabolize to CO2 and H2O using H+ ions)

• Indications:

Fluid replacement

For alkalinization

• Caution:

CHF, Edema with Na retention

Renal failure and metabolic alkalosis

Sterofundin

• Composition : Na= 145 mEq, K= 4 mEq, Cl= 127 mEq, Ca= 2.5 mmol,

acetate= 24 mmol, Malate 5 mmol, Mg= 1 mmol per litre

• pH: 5.1-5.9, osmolarity= 309 mosm/L

• Indications:

Fluid replacement in isotonic dehydration

For alkalinization

• Caution:

CHF, Edema with Na retention

Renal failure/ hyperkalemia and metabolic alkalosis

Hydroxyethyl starches

• Modified natural polysaccharides similar to glycogen

• To delay α-amylase breakdown: natural starches are substituted with

hydroxyethyl groups

• Classified into: high (hexastarch), medium (pentastarch) and low

(tetrastarch) substitution. High Molar substitution delays degradation

• Plasma expanding effect depends on the concentration solution

• Advantages:

High hemodilutional capacity

Vascular resistance is reduced by lowering blood viscosity

(beneficially influence tissue perfusion)

Hydroxyethyl starches cont…

• Disadvantages:

Decrease levels of vWF and factor VIII activity, impair platelet

function, induce platelet damage (apparent when >1500ml

given within 24hrs)

Renal dysfunction (hyperviscosity of urine in dehydrated pts)

Pruritis may occur d/t extravascular deposition of starch

Allergic reactions (although lowest c/f other colloids)

Clearance takes over several weeks (although oncotic activity is

lost after 24hrs)

Gelatins (Haemaccel)

• Produced by degradation of bovine collagen and chemical

modifications

• Commercially available preparations: 3.5%-5.5%

• Adv:

Average molecular weight: 30-35 kD, small molecular weight,

rapidly cleared from the bloodstream by glomerular filtration

(80%)

Volume effect 70-100%

Do not accumulate in the body, have no dose limitations, almost

no adverse effects on the kidneys

Gelatins cont…

• Disadv:

Hemostasis could be impaired (interference with coagulation

factors, disturbance in the quality of fibrin polymerization)

Bovine origin (hypothetical potential of transmitting prion

diseases)

Most frequent incidence of allergic reactions (6 times c/f HES)

Cleared rapidly so repeated infusions of gelatins are necessary to

maintain adequate blood volume

Dextrans• Biosynthesized from sucrose by the bacterium Leuconostoc

mesenteroides

• Dextran 40 and dextran 70 (molecular weights of 40 and 70 kD)

• Adv:

Molecules less than 50 kD are rapidly eliminated by the kidneys

Decreases blood viscosity, improved microcirculatory blood and

tissue perfusion

Used by vascular and plastic surgeons to assist in keeping

microvascular anastomosis patent

Dextran 70: generally preferred for volume expansion

Dextran 40: improve blood flow in the microcirculation

Dextrans cont…

• Disadv:

Induces a dose-dependent hyperfibrinolysis, decreased levels of

vWF and associated factor VIII (VIII:c) activity, Max daily dosing:

1.5g dextran/ kg body wt

Coat red cells (interfere with cross matching, inc ESR)

Impaired renal function (tubular obstruction, swelling, and

vacuolization of tubular cells due to hyperviscous urine)

Severe anaphylactic reactions (Prevention: dextran 1 (Promit), a

low-molecular-weight hapten, administered few minutes before

any dextran infusion)

Human Albumin

• Purified from pooled human plasma

• Commercially available as a 5% (iso-oncotic), 20% & 25%

(hyperoncotic) solution

• Heated and sterilized by ultrafiltration, so risk of bacterial or viral

disease transmission eliminated

• Functions of albumin: maintaining the plasma oncotic pressure,

transport protein, plasma buffer

• Predictor of mortality risk in patients with acute and chronic illness

(for each 2.5 g/L decrement in serum albumin concentration the risk

of death increases by 24% to 56%)

• 5% albumin: 70% effective, effect lost in 12 hrs

Human Albumin cont…

• Uses:

Acute restoration of an effective circulating volume due to

hemorrhage

Acute management of burns

Hypoproteinemia

• Disadv:

High cost

Even detrimental in burns, hypoproteinemic pts.

Allergic reactions (equal to HES)

Colloid vs Crystalloid

• For crystalloids: inexpensive, adverse effects are rare or absent, no

renal impairment, minimal interaction with coagulation other than

dilution, no tissue accumulation, no allergic reactions

• For colloids: much better volume-expanding properties, minor edema

formation, improved microcirculation

• When compared neither type of fluid provided a survival benefit

• So in patient with hypovolemia d/t dehydration (uniform loss of ECF),

crystalloids are benefecial

• In patients with hypovolemia secondary to hypoalbuminemia, colloids

benefit the patient more.

Balanced vs Unbalanced Solutions

• Large volume resuscitation with normal saline causes hyperchloremic

metabolic acidosis (l/t organ hypoperfusion, increased morbidity,

especially gastrointestinal, neurologic, renal damage, blood loss)

• Buffered formulations (RL, Isolyte P) maintain a higher plasma pH and

less chloride load, fewer incidences of hyperchloremic metabolic

acidosis, low concentration electrolytes l/t reduction in postoperative

morbidity.

Balanced crystalloid solutions are preferred in the perioperative period

• Colloids suspended in balanced solutions now available, are better

Maintenance Fluid therapy

• Normal ongoing losses in 70 kg man: 2100-2500ml/day

• Fluid to be given calculated acc to Holliday & Segar formula”4-2-1”

• Best maintenance fluid: balanced isotonic crystalloid (RL) untill the

patient is NPO

• Best estimation of fluid requirement is made by weighing the

patient daily

• Neuraxial anesthesia: Preloading with 250-200ml fluid appears to

temporarily increase preload and C.O. without consistently

increasing arterial B.P. or preventing hypotension.

Replacement Fluid therapy

• Bleeding/ 3rd space loss/ Evaporation/ Sweating

• Assessment: Estimate/ measure + Clinical examination +

laboratory data

• Type of fluid depends on the type of fluid lost or any

electrolyte imbalance already present

• Rate of administration: Arbitrary, depends on severity of

deficit (diff in case of hyper/hypo Na)

Post Operative Fluid

• Aim: BP > 100/70mm Hg, Pulse <120, Urine 30-50ml/hr,

normal temperature, respiration, sensorium

• When to give:

Usually for minor surgeries (no gut handling) started orally

4-6 hrs postop.

In Major surgeries( no gut handling e.g. THR/ cardiac) 24-

48 hrs of IV fluids

When intestinal resection: needs few days of IV fluids

Post Operative Fluid cont…

• Routine postop orders for fluids for 3 days:

First 24 hrs: 2litre D5 or 1.5litre D5 + 500ml NS

(except neurosurgical patients, major surgeries)

2nd post op day: 2 litre D5 + 1litre NS

3rd postop day: Same + 40-60 mEq KCl

Modified according to individual case

Preferred fluid therapy

• In Vomiting: (Hypovol, HypoK, HypoCl, Meta alk) NS

• In Diarrhoea: (Hypovol, HypoNa, HypoK, HyperCl, Meta Acid) RL & NS

• CHF: Oedema d/t salt & water retention (HypoNa) Avoid Na rich fluids

like RL & NS, Don’t chase urine output

• ARDS: Pulmonary edema d/t inc capillary permeability, Keep dry,

maintain balance b/w diuretics and fluid to keep MAP >75-80mmHg

• In Neurological ds: maintain euvolemia (no hypotension) caution

during mannitol, avoid hypotonic fluids and hyperglycemia (avoid D5),

RL appropriate for small vol infusion, NS is ideal

• DKA: Glycosuria, osmotic diuresis, meta acid, K+ def, Mg & P def.

Preferred fluid therapy cont…

• DKA cont…: Initial therapy NS, If no hypotension and good urine

output RL can be given, KCL can be added here, Further can switch to

0.45 Saline (acc to Na conc), once sugars below 250mg/dl D5 is to be

used.

• In Renal Disease: Fluid restriction (Urine output + 500ml), in

edematous pt so not chase the urine, salt restriction 2-3g/d, Avoid

hyperkalemia (RL).

• In nephrotic NS prefered

• Pre-renal ARF: NS prefered

• In CRF: 5D or 10D prefered, limit fluid admn

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