J.J.M MEDICAL COLLEGE, DAVANGERE

DEPARTMENT OF ANAESTHESIA AND

CRITICAL CARE

SEMINAR ON

INTRA-VASCULAR FLUIDS (Crystalloids and

Colloids); INTRAOPERATIVE FLUID MANAGEMENT

Presenter:

Dr. Tanmoy Roy

Moderator:

Dr. Shilpashree A.M

M.DDATE: 27TH JULY ‘ 10

INTRODUCTION TO IV FLUID THERAPY:

Must know……….

• Etiology of fluid deficit and type of electrolyte imbalance

• Associated illness (DM, HTN, IHD etc.)

• Clinical status (hydration, vital data, urine output etc.)

INTRO……….contd.

What comes to our mind ?????

• When to give fluid and when to avoid?

• Which fluid to give in which situation and which route?

• How much to give and how to calculate?

• At which rate to infuse and how to calculate the drop rate?

• What are the contraindications to different type of IV fluids and why?

• How to correct electrolyte imbalance?

FROM LEVEL 0………..BASICSIndications:

1. Conditions when oral intake is not possible eg. Comma, anesthesia, surgery

2. Severe vomiting and diarrhea

3. Moderate to severe dehydration and shock, where urgent and rapid fluid therapy is indicated

4. Hypoglycaemia where 25% glucose is life saving

5. As a vehicle for various IV medication (antibiotics, chemotherapeutics, insulin, vasopressor agents

6. TPN

7. Treatment of critical problems: Shock, anaphylaxis, poisoning, urinary stones etc.

Contraindications:

Able to take orally

CCF or volume overload states

Disadvantages:

More expensive, needs strict asepsis

Possibly only in hospitalized patients under skilled supervision

Improper selection of type of fluid can lead to serious problems

Improper volume and rate of infusion can be life threatening

Improper technique of administration can be dangerous

Complications:

LOCAL- Hematoma, Infiltration, Infusion phlebitis

SYSTEMIC- Circulatory overload, Rigors, Air embolism, Septicaemia

OTHERS- Fluid contamination, Mixing of incompatible drugs, Improper technique, Human error.

TYPES OF INTRAVENOUS FLUIDS Crystalloids

Colloids: Natural colloids (albumin, plasma)

Synthetic colloids – Gelatins, Dextrans, HES

Depending on Tonicity: Hypertonic: (solutions with higher osmolality) e.g.

10%, Dextrose, 25% & 50% dextrose, 20% NaCl, 7.5% NaCl, 5% DNS

Isotonic: – e.g. 0.9% NaCl, RL, isolyte solutions

TYPES……………..contd. Hypotonic: (solutions with low Osmolarity) (prepared

by adding distilled water in equal amounts)eg: 5% Dextrose, 0.45% NaCl

Baracity: Isobaric – e.g. all crystalloids

Hypobaric – not in use routinely

Hyperbaric – prepared by adding high specific gravity compounds

Fluids may be: Plasma expanders – e.g. colloids & crystalloids.

Plasma substitutes – e.g. colloids

Others: Maintainance fluids- to replace fluids lost from lungs,

skin, urine and faeces. ( 5% dextrose, dextrose with 0.45% NaCl solution).

Replacement fluids- to correct deficit caused by gastric drainage, vomiting diarrhea, burns etc (Isotonic saline, DNS, Ringer lactate, Isolyte-M,P,E & G).

Special fluids- In hypoglycaemia, hypokalaemia and metabolic acidosis (25% dextrose, Inj. Sodium Bicarbonate and Inj. Potassium Chloride)

TYPES……………..contd.

COMPARING CRYST. & COLL.CRYSTALLOIDS COLLOIDS

Aqueous solutions of low molecularweight ions with or without glucose

High molecular weight substances,similar to plasma proteins

Readily pass through semi-permeablemembrane (“Extra vascular space

expanders”)

Molecular size is large and do not crosscapillary membrane (“Intravascular

space expanders”).Intravascular t1/2 = 20-30 minutes Intravascular t1/2= 2-8 hours

Reduce plasma colloid osmotic pressure Maintain plasma colloid osmoticpressure

Have poor capillary perfusion Have good capillary perfusionRisk of over hydration/tissue edema is

obviousIt is insignificant

No anaphylactic reaction Risk of anaphylaxis is moreInexpensive Expensive

Readily available, easy to store and welltolerated by patients – some advantages

Not so

Indications: Rx of dehydration of any cause, Hypoglycemia (5% 10% D) Hypochloremia, hyponatremia of any

cause Preloading fluid in regional block(SA)

Intraoperative/postoperative maintenance fluid

Indications: Fluid resuscitation prior to arrival of

blood Severe hypoglobuminemia Burns Fluid boluses in critically ill patient

where crystalloid use would be excessive.

INDIVIDUAL I.V FLUIDSCRYSTALLOIDS:

5% DEXTROSE:-

1 liter of fluid has 50 gms glucose

Pharmacology: After consumption of glucose,

remaining water is distributed in all compartments, so is the best fluid to correct intracellular dehydration

When there is need for water but no electrolytes

Energy supplied is about 170 Kcal/lit.

Indication: Rx of dehydration due to inadequate water intake or

excess water loss

Pre and post op fluid replacement

IV administration of various drugs

Rx of ketosis in starvation, diarrhea etc

Along with frusemide to correct hypernatremia of salt poisoning

Contraindications: Cerebral oedema- due to its hypotonicity

Neurosurgery- raises ICP

Acute ischemic stroke-hyperglycaemia aggrevates cerebral ischaemia

Hypovolaemic shock- hyperglycaemia and osmotic diuresis

Hyponatraemia and water intoxication- causes diuresis, water and salt loss

Blood transfusion-hemolysis and clumping

Uncontrolled diabetes

Precautions: IV administration causes local pain ,

irritation and thrombophlebitis

Prolonged use can cause hypokalaemia, hypomagnesaemia and hypophosphataemia

Rate of administration:0.5gm/kg.wt/hour; above this rate can

lead to glycosuria

10% DEXTROSE & 25% DEXTROSE:-

1 liter of fluid has 100 gms glucose and 250 gms respectively

Pharmacology: It is hypertonic, isobaric crystalloid fluid.

More beneficial to avoid cellular tissue hypoxia in case of hypotension

Useful in avoiding cellular dehydration.

Indications: In Diabetes Mellitus to provide ready supply of glucose to

avoid hypoglycemia .

In liver disease, if given as first drip,it inhibits glycogenolysis and gluconeogenesis

For treatment of hyperglycemia with 10 units of regular insulin

25% D 100 ml is infused slowly to prevent hypoglycemia .

Contraindications:

Unless and until indicated it should not be used as it causes Thrombophlebitis .

5% DEXTROSE SALINE (DNS):-

Hypertonic, isobaric crystalloid solution. Most commonly used IV fluid as it contains

both 5% dextrose and normal saline(0.9 %).

Each 100ml contains: 5gm anyhydrous dextrose 0.9 gm sodium chloride Water for injection Na 154 mEq/lt, Cl 154 mEq/lt

Provides about 200 calories /L.

Used to treat various dehydration of various causes(sweating,vomiting).

Used as maintenance fluid in intraoperative and postoperative period .

Should be used cautiously in cardiac, renal, and hepatic disorder.

ISOTONIC SALINE:-

Isotonic, isobaric 0.9% W/V solution

Each 100 ml contains: 0.9 gm sodium chloride Water for injection Na 154 mEq/lt, Cl 154 mEq/lt

It is Isotonic with body fluids thus it does not attract water nor it allows water to pass from it .

Specific indications: Dehydration of any cause Hypovolemic shock Preparation of hypotonic solutions in treatment of post

spinal headache For detection of epidural space For making various drips:

Thiopentone sodium in status epilepticus Nor- adrenaline drip Lignocaine HCL drip

Contraindications: Hypernatremia and hyperchloremia of any cause Raised ICT due to any cause Edema due to anaemia, hypoproteinemic nephritic

syndrome Old age, hypertension CCF of any cause Pulmonary edema

Complications: Na and water retention water intoxication Pulmonary edema and edema of any dependant parts Renal failure due to Na overload

RINGER LACTATE SOLUTION:-

Also known as Hartmann solution or balanced salt solution.

Isotonic, isobaric solution

Each 100 ml contain: Na lactate 32 mg, NaCl 60 mg, KCl 4mg, CaCl 22.7 mg

Na- 131 mEq/ml, Ca- 2mEq/ml, HCO3- 29mEq/ml, K- 5mEq/ml Cl- 110mEq/ml

Lactate rapidly metabolizes in liver to form bicarbonates which helps in metabolic acidosis.

Indications: In Hypovolemia as plasma expander

Maintenance of normal ECF and electrolyte in intraoperative and postoperative period

Preloading fluid before regional block

Replacing fluids in burns, fractures and peritoneal irrigation.

Contraindications: Liver failure (lactate accumulation ) ARF Severe hyperkalemia with renal failure Pt on diuretic therapy

HYPERTONIC SALINE:-

These are small volume resusicitation fluids.

Causes rapid shift of fluid from intracellular to intravascular compartment and restores capillary flow.

% SOL gm/l Na(mEq/l)

Cl(mEq/l)

NaCl

3% 30 573 573

5% 50 855 855

7.5%

75 1283 1283

On myocardium: Cardiac function may be improved by direct vasodilator

effect Increases myocardial availability of Calcium

Clinical application: Trauma resusicitation Burns Head injury resusicitation, very effective Thoraco abdominal surgeries

ADVANTAGE DISADVANTAGE

Excellent volume replacement Electrolyte imbalance(hypochloremia, hypernatremia)

Improves cardiac function Cellular dehydration

Increases myocardial blood flow Hypokalemia

Reduced ICP Thrombophlebitis

Reduced incidence of ileus Worsening of uncontrolled hemorrhage

Inexpensive, rapidly available, long shelf life

Rapid infusion induced hypotension

ISOLYTE SOLUTIONS:-

Isotonic, isobaric ,crystalloid fluid.

Isolyte G:

1 liter of the fluid contains: Glucose 50 gms Sodium 65 mEq Potassium 17 mEq Chloride 150 mEq Ammonium 69 mEq

Useful in Upper intestinial obstruction (acute gastritis with continuous vomiting)

Isolyte M (Maintainance fluid with 5%- Dextrose):

1 liter of the fluid contains: Glucose 50 gm Sodium 40 mEq Potassium 35 mEq Chloride 38 mEq Phosphate 15 mEq Acetate 20 mEq

Richest source of potassium (35 mEq/ml) so can be used to treat hypokalemia of any cause like bilious vomiting, diarrhea.

Useful in upper and lower intestinial obstruction, best given in perioperative period.

Isolyte E (extracellular replacement solution):

1 litre of fluid supplies: Glucose 50 gms Sodium 140 mEq Potassium 10 mEq Chloride 103 mEq Acetate 47 mEq Calcium 5 mEq Magnesium 3 mEq Citrate 8 mEq

Useful in Lower intestinial obstruction, diarrhea and biliary fissure

Isolyte P:1 litre of fluid supplies: Glucose 50 gms Sodium 125 mEq Potassium 20 mEq Chloride 22 mEq Acetate 23 mEq HPO4 3 mEq Magnesium 3mEq

Isotonic, isobaric , infusion fluid.

Multiple electrolyte and dextrose solution.

Useful in all paediatric cases from neonates to old children, as it provides more water and equivalent electrolyte requirement for paediatric age group .

COLLOID SOLUTIONS:

Properties of an ideal plasma replacement fluid: Rapidly replaces blood volume losses Restore hemodynamic balance Normalizes microcirculatory flow Long intravascular life Rapidly metabolized and excreted and well tolerated Free of anaphylactoid reactions No risk of infection Cost effective

“Unfortunately there is no ideal colloid fluid that fulfils all these criteria”.

Colloids

Natural colloids

Albumin 5%,20% 25%

Plasma proteins 4%

5%

Artificial colloids

HES

Fresh Frozen Plasma

Dextrans

Gelatins

ALBUMIN:

Naturally occurring plasma expander Produced from pooled human plasma or

placenta Accounts for 60-80% of normal plasma oncotic

pressure Minimal risk of disease transmission(heated for

600C for 10hrs and sterilized by ultra filtration) Molecular weight 69KDA (69000)

Preparation 5% albumin-isooncotic 20 % - 25 % albumin -hyperoncoticHalf life normally 16 hrs and it can be as short as 2 to 3 hrs in pathological conditions . Problem with this blood product

AvailabilityHigh costGeneral scarcity at blood bank levels

Indications Severe hypoalbuminemia

Immunoglobin deficiency

Plasma cholinesterase deficiency

Inhibition of platelet aggregation

Disadvantages Cardiac decompensation when infused rapidly

Albumin administration does not decrease morbidity or mortality in critically ill patients

25% not the colloid of choice for high volume resusicitation

DEXTRANS: Water soluble glucose polymers formed

by bacterial action(leucocytic mesenteroids)on sucrose through enzyme sucrase

Effective plasma volume expander due to colloid osmotic effect

Sp. Gravity is slightly greater than blood Broken down enzymatically to dextranase

and excreted in urine.

Preparation: Dextran 150 - 6% dextran in 5% glucose

on normal saline Dextran 110 – 5% dextran in 5% glucose

on normal saline Dextran 70 – 6% dextran Dextran 60 – 3% dextran Dextran 40 -- 10% dextran

Large dextran molecule can block renal tubules and damage kidney, so dextrans should not be given more than 1-2 L in 24 hrs.Limited daily dosing of 20ml/kg.

Advantages: Decreases blood viscosity, platelet viscosity,RBC

aggregation Improves blood flow through microcirculation Preloading with 10-15 ml/kg of dextran before SA block

prevents hypotension

Clinical advantages of Dextran: Periphereal vascular disease-improves blood flow through

microcirculation Prevention of excessive platelet activation and release of

micro emboli during end arterectomy & skin grafting and other vascular procedures

Disadvantages: Highest risk of anaphylaxis Prolongs BT- risk of bleeding Intereferes with grouping and blood typing Worsens renal failure Impairs BT,Platelet function ,ESR

Contraindications: Known sensivity of dextran Fixed low cardiac outpatient status Cerebral edema Raised ICT and marked hemorrhagic tendencies eg

thrombocytopenia.

GELATINS: Second most common plasma expander after

HES. Prepared from hydrolysis of polypeptides Derived from Bovine collagen Mol wt 30-35 KDA Plasma half life 4-6 hrs

Formulations: Cross linked gelatins- eg Gelofondiol Urea linked gelatins- eg Haemaccel Succinylated gelatins- eg Gelofusine Haemaccel(300ml,500ml) obtained from high

grade gelatins

Each 100 ml contains: Polymer from degraded gelatine 3.5 gm Na 145 mEq/ml, K 5.1 mEq/ml, Ca 6.25 mEq/ml, Cl

145mEq/ml Molecular wt 30,000-35,000

Indications: Procedures involving extra corporeal circulation, eg -

priming the heart lung machine Prevention and treatment of hypovolemia(burns, post op

blood loss, spinal/epidural anaesthesia)

Advantages: Preservative free preparations Rapid excretion through urine, plasma clearance of 3 days,

complete excretion from body in 1 wk. No effects on coagulation

Disadvantages: Bovine source- risk of transmission of disease

Incidence of anaphylactic reaction

Histamine release- Haemaccel preparation

Cannot be given with blood

Not more than 1L in 24 hrs

Contraindications: Shock due to septicemia, cardiogenic, anaphylactoid shock

Oedema due to CCF,RF, DIC

Hydroxy-ethyl starch (HETASTARCH): Natural non synthetic product Available along with isotonic NaCl Osmolarity is similar to normal

physiological osmolarity Dosage 20ml/kg/hr Available concentration 3% 6% 10% in

isotonic NaCl or RL with or without dextrose

Teratogenic potential

Features of HES: Low incidence of anaphylactoid reaction Metabolized by body amylase and

excreted by renals Undergoes phagocytosis in RE system Improve splanchnic perfusion in both

trauma and septic patients

Disadvantages: Severe pruritis; very rare chance of anaphylaxis (0.006%) Rise in serum amylase levels (macroamylasemia) Dehydration of interstitial space may occur and impair

transport and exchange of nutrients between the body compartments

Bleeding tendency

Indications: Hypovolemia Cardiac priming during cardiopulmonary bypass Hemodilution

Contraindications: Hemorrhagic disorders Severe CCF Renal failure Patient allergic to starch

PROPERTIES OF COLLOIDS IN A NUTSHELL

Colloid COMPOSITION

Concen

tration

Mol.Wt(in KD)

% Intravascula

r

Colloid osmotic

pressure(mm Hg)

Intravascular half life (hr)

Albumin Albumin 5 % 69 80 20 >24

Dextran 70 Polysaccaride

6 % 70(20-175)

100 40 6-12

Dextran 40 Polysaccaride 10% 40(15-75) 100 2-3

Hydroxyethyl starch

Amylopectin 6% 450(10-1000)

100 30 >24

Pentastarch

10% 264(150-350)

100 40 10

PERIOPERATIVE FLUID MANAGEMENT

To consider:

Age of patient

Type and duration of surgery

Type of anaesthesia – General or Regional

Absence or presence of significant blood loss

Major organ system dysfunction

Intravascular volume disturbances

Electrolyte abnormalities

THE PRE-OPERATIVE PEROID: PREOPERATIVE FASTING GUIDELINES

All adults are kept nil per orally for 6 hrs. Children and patients who have continuing & excessive

fluid loss can become dehydrated

AGE CLEAR LIQUID MILK/SOLIDS

< 6 months 2 hrs 3-4 hrs

6-36 months 2 hrs 4-5 hrs

>36 months 2 hrs 4-6 hrs

Fasting regimen in children as per ASA guidelines :

EVALUATION OF VOLUME STATUS

Physical examination : Measurement of arterial blood pressure(supine and sitting

position )

Peripheral pulses - felt with good volume

Adequate circulating volume - Warm pink extremities with brisk capillary refilling

Resting tachycardia and or cardiac rhythm - Abnormally high or low blood volume with poor end organ failure

Skin tugor, mucousa – Dryness, loss of tugor

Low urine output, decreased level of consciousness

In absence of glycosuria, diuretics manitol infusion urine output of 0.5 -1 ml/kg/hr implies, but does not prove adequate blood vol.

Laboratory tests:

TEST NORMAL

RANGE

SUGGESTHYPOVOLEM

IA

LIMITATIONS

BUN (mg/dl)

8-20 >20 Variable protein intake, GI bleed, catabolism renal compromise

Serum creatinin

e(mg/dl)

0.5-1.2 >1.2 Advanced age, variable muscle mass , catabolism

BUN:S.Cr

<20 >20 -do-

Urinary sodium

>30 <20 Renal compromise

Urinary osmolali

ty

<800 <400 Renal compromise

Serum lactate

<2 >3 Late sign

Metabolic

acidosis

22-26 >26 Diverse cause

METABOLIC REQUIREMENTSA 70 Kg man requires about 110ml/ hr of water and 110 kcal/ hr or 2640 ml of water and 2640 kcal/day.

Body weight(kg)

Fluid rate(ml/kg/hr)

Fluid rate(ml/kg/day)

0-10 4 100

11-20 2 20

21 + 1 5

Daily requirement of Na+ is 1.5 mEq/kg/day and that of potassium is 0.8-1.5 mEq/kg/day.

Obligatory glucose need of brain and RBC are 2mg/kg/min.

Gastric drainage of 0.5 L/day loses 30 to 50 mEq of sodium and 50-65 mEq of chloride. This is replaced by half normal (0.45%) saline.

THE INTRA-OPERATIVE PEROID:

GOALS Maintain adequate oxygen delivery Maintain normal electrolyte concentrations Maintain normoglycemia

ESTIMATION OF FLUID REQUIREMENTS Preoperative fluid deficit Maintenance fluid Intraoperative blood loss Third space loss/Redistribution Other losses

Preoperative fluid deficit:

Fluid deficit = (Maintainance fluid requirements X Hours of NPO) + Preop. External losses and 3rd space losses

When hypovolemia is present, sufficient fluid should be infused to restore mean arterial pressure, heart rate and filling pressure to near normal before induction

The fluid infusion rate for normal patient should set to be deliver 3 to 4 times the maintenance rate until the calculated deficit has been corrected.

Intraoperative blood loss:

It is estimated by the following: Measurement of blood in surgical container Visual estimation of blood on surgical sponge 4x4 cm

surgical sponge holds 10 ml of blood and soaked laprotomy pad holds 100-150 ml

By weighing the sponges before and after use Serial hematocrit and Hb estimation

Blood loss should be replaced by: 3ml of balanced salt/normal saline for each ml of blood lost 1 ml of colloid for each ml of blood lost 1 ml of packed RBC infusion for 2 ml of blood lost

Calculating allowable blood loss:

ABL=EBV X HCT(initial)-HCT(target)/HCT(initial)

 Estimated red cell mass (ERCM) = EBV X HCT(initial)

  

Other losses: Evaporative loss –exposure of peritoneal and pleural surfaces

to operating room environment (Evaporative loss in laparotomy is about 150 ml/hr)

Respiratory loss –approx 400 ml, due to inadequate humidification of anaesthetic gases

Urinary loss

ERCM(target) = EBV x HCT(target)

HCT= hematocrit

EBV =estimated blood

volume

ABL = allowable blood

volume

Fluid replacement guidelineCalculated by formula:

Rate of fluid administration =CVE +fasting deficit (no of hrs fasting x maintenance of fluid) + maintenance for that particular hour+ external losses +third space loss

COMPENSATORY INTRAVASCULAR VOLUME EXPANSION (CVE)

This is the volume infused to compensate for the vascular dilatation and cardiac depression caused by anaesthesia. Best compensated with 5-7ml/kg of balanced salt solution

Replace:1st hr- half of the deficit +maintenance2nd hr – ¼ th of the deficit +maintenance3rd hr - ¼ th of the deficit +maintenance4th hr – only maintenance fluid

Redistribution/3rd space loss: The third space is an area in the body that is occupied by

fluids that are not in equilibrium with the blood stream

Primarily results from tissue edema and transcellular fluid displacement. Functionally this fluid is not available to the vascular space .Magnitude of the third space loss is proportional to the amount of tissue manipulation.

Examples include burns, bruises, traumatized operative bed, traumatically injured tissues and infarcted tissue

Minimally traumatic surgery(ophthalmic/otolaryngological/Orthopaedic procedures using tourniquet)

Requires onlyMaintenance fluids

Mildly traumatic surgery(tonsillectomy,herniorraphy,appendicectomy)

4 ml/kg/hr

Moderately traumatic(thoracotomy) 6-8 ml/kg/hr

Severely traumatic surgery (bowel resection ,cardiac surgery)

10 -15 ml/kg/hr

Maintainance fluids:

Maintenance fluid is based on Holliday and Segar formula also called 4-2-1 formula which is as:

Body weight(kg)

Fluid rate(ml/kg/hr)

First 10 kgs 4

Next 10-20 kgs

2

For each kg above 20 kgs

1

INTROPERATIVE MONITORING Urine output 1ml/kg/hr is the normal output:

<0.5 ml/kg/hr- suggests significant deficit  Urine sp gravity <1.020- normal hydrated patients:

>1.030-1.040- suggests deficit of 1-3 lts>1.040- severe dehydration deficit in excess of 31 %

  Vital signs – pulse ,BP measurements in patients lying supine

position  Physical assessment:

No dry skin, mucous membraneNo thirst in an awake patients

Invasive monitoring –central venous pressure (CVP),Pulmonary capillary wedge pressure(PCWP)

Laboratory tests –Periodic monitoring of hematocrit

ANAESTHESIA AFFECTING FLUID BALANCE DURING SURGERY

REGIONAL ANAESTHESIA GENERAL ANAESTHESIA Central neuraxial blockade

produces relative hypovolemia due to peripheral pooling of blood, the degree of which is proportional to the level of the sympathetic blockade

The effect may be minimized by preloading the patient with crystalloid and/or Colloid solutions

Two components influence fluid management:1) Anaesthetic drugs – produce

vasodilatation, decrease inotropy and bradycardia, except Ketamine.

2) Anaesthetic technique – Mechanical ventilation affects fluid balance by decreasing the release of Atrial natriuretic hormone and PEEP increases releases of ADH. Thus the patient retains sodium and fluid

THE POST-OPERATIVE PEROID:

Depends on:

Magnitude of intraoperative tissue manipulation

Quantity of blood loss

Adequacy of intraoperative fluid management

CHOICE OF FLUID: 1st post op day -5% dextrose 1500 ml +500 ml of isotonic

saline 2nd post op day -2L of 5% dextrose + 1L of NS 3rd post op day – similar fluid +40- 60 mEq of K+

per day or RL

FLUID MANAGEMENT IN SPECIAL CASES

PAEDIATRIC PATIENTS:

PHYSIOLOGICAL CONSIDERATIONS:

High total body water and ECF volume compared to adults

Neonates and young infants are more sensitive to hypovolaemia. This is due to:Immature myocardium

Tendency for biventricular failure, sensitivity to volume overloading and heart rate dependent cardiac output

Immature sympathetic innervations

New born has limited capacity to compensate for volume excess or volume depletion. This is due to:Low GFR(25% of adult) - reaches adult GFR by 2 yrs of age

Low concentrating capacity of urine (Term babies- 600-700mOsm/kg max; Adults- 1200 mOsm/kg max)

Risk of hypoglycemia is more due to:limited hepatic glycogen stores

increased BMR

PERIOPERATIVE FLUID REQUIREMENTS:

A programmable infusion pump or a buret with a microdrip chamber should be used for accurate measurements.

Fluid overload is diagnosed by: prominent veins decreased serum Na flushed skin loss of folds of upper eye lids increased BP

MAINTAINANCE FLUID REQUIREMENTS: CALORIMETRIC METHOD-

by MA Holliday and WE Segar in 1957

Body weight Caloric expenditure per day

Upto 10 kg 100 k cal/kg

11-20 kg 1000k cal +50 kcal >kg

Above 20 kg 1500 kcal + 20kcal/kg>20kg

For every 100 kcal metabolized; 100 ml of water, 2.5 mEq of Na and 2mEq K+ is recommended.

BODY SURFACE AREA METHOD-It is based on the concept that caloric expenditure is proportional to BSA.

Calculated by:

Fluid requirements-1500ml/m2/day Na requirements – 30-50 mg/m2 /day K requirements – 20-40 mg/m2/day

AGE IN DAYS OR WT(IN KG)

INFUSION(ml/kg/day)

HOURLYml/kg/hr

TYPE OF FLUID

Day 1 70 3 10%dextroseDay 2 70-80 3-4 10%dextrose in 0.22% salineDay 3 80 4-5 10%dextrose in 0.22% salineDay 5 90 4-5 5% dextrose in 0.22% saline0-10 kg 100 4ml/kg/hr 5% dextrose in 0.45% saline10-20 kg 1000+50ml/kg 40+2

ml/kg/hr5% dextrose in 0.45% saline

>20kgs 1500+20ml/kg 60 ml+1 ml/kg/hr

5% dextrose in 0.45% saline

DEFICITS: Preoperative fluids are best replaced with a balanced salt

solution.

Most commonly Isolyte P is used in young patients (up to 12 kg)

 BLOOD LOSS: It is typically replaced with non glucose containing

crystalloid or colloid solution until patient hematocrit reaches a predetermined level

In premature and sick neonates 40-50% hematocrit

Infants and older children 20-26 %is acceptable

THIRD SPACE LOSS: It is estimated by extent of surgery Lactate Ringer solution is best replacement

Minor traumatic surgery 1-2ml/kg/hr Moderate traumatic surgery 4ml/kg/hr Severe traumatic surgery >6ml/kg/hr

HEART FAILURE:

Goals: Optimize cardiac output Avoid Na overload Diminish edema Correct common electrolyte abnormalities

Preload: Maintaining ideal preload is facilitated by measuring

preload by CVP,ECHO, Pulmonary artery occlusion pressure(PAOP) & End diastolic volume .

Patients with a history of cardiac failure scheduled for major or prolonged surgery should have monitoring instituted preoperatively and an intravascular fluid challenge (500-700mL/70 kg crystalloid) performed to identify optimal preload level.

Choice of fluid; Colloids are used to maintain intravascular volume. Fluids should be infused at a low maintenance level and

flush fluids and sodium dosage should be measured. Dilutional hyponatremia is common in cardiac failure

inspite of Na retention. Diuretics are used to excrete excess free water.

CEREBRAL EDEMA:

Goals: Maintain cerebral perfusion pressure Avoid change in CVP and systemic blood pressure Avoid change in plasma osmolality Avoid hyperglycemia

Choice of fluid: A degree of water dehydration without hypovolemia is

desired guided by plasma Na concentrations maintained at 142-148 mEq/L

RL or isotonic saline is used as maintenance fluid Isotonic crystalloids or colloids should be used to sustain

intravascular volume

RENAL FAILURE:Goals: Avoid excessive IV fluid administration and ECF volume

expansion Maintain or correct electrolyte and acid base ststus Prevent precipitating conditions that would require dialysis

in immediate Post op period(like hyoerkalemia, pulmonary edema,

Metabolic acidosis) Avoid hypovolemia. If dialysis is to be done, it should be

scheduled 12-24 hrs preoperatively.

Choice of fluid: Isotonic fluid without K+ with reduced amt of Cl and

increased amount of buffer is preferred Correction of 3rd space loss :Crystalloids(11-12mL/kg/hr) Blood loss: Colloids or PRBC’s

HEPATIC FAILURE:

Goals: Avoid increasing interstitial fluid overload Maintain normal K concentration Maintain intravascular volume

Choice of fluid: Crystalloid solutions are better avoided as they expand

already expanded ECF volume Hypovolemia treated by infusing 5% albumin

PATIENTS WITH SMALL BOWEL OBSTRUCTION:

Fluid shifts during small bowel obstruction:Normally about 7-9 liters of fluid are secreted into the upper GIT daily. They can be distributed as:

Abdominal Viscera 24 hour volume (ml)

Saliva 500-2000

Stomach 1000-2000

Pancreas 300-800

Bile 300-600

Jejunum 2000-4000

Ileum 1000-2000

In early small bowel obstruction, 1500 ml of fluid accumulates in the bowel. Once intestinal obstruction is well established and vomiting occurs, 3000 ml of fluid may be present.

When the patient exhibits hypotension and tachycardia, indicating circulatory instability, as much as 6000 ml of fluid is in the gut.

There is loss of vast quantity of isotonic ECF. As the obstruction continues, there is gradual decrease in plasma chloride and sodium concentration.

Goals: Primary goal is the initial restoration of IV volume to a

state of normovolaemia. This will lead to the optimization of oxygen delivery to the tissues.

Second goal is the correction of electrolyte disturbances, including acid-base derangements which may exist

As the fluid lost to an obstructed segment of bowel is similar to plasma in composition, a balanced salt solution such as lactated Ringer’s solution is appropriate to use for fluid resuscitation.

Guide to fluid volume replacement: Central Venous Pressure Hourly urine output Arterial blood pressure Heart rate Skin tugor

CONCLUSION

Fluid management for any particular medical condition has always been an interesting but challenging field for the physician. Moreover, where IV fluids can save the life of an individual, at the same

time unjust and inappropriate administration of fluids, both in volume and

type, can be life threatening

REFERENCES Miller’s Anesthesia 7th ed

Clinical Anesthesiology: Morgan 4th ed

Clinical Anesthesiology: Paul G Barash

Practical guideline on fluid therapy 2nd ed: Dr Sanjay Pandya

Review of Medical Physiology: William F Ganong

“THANK YOU”