FLUIDS AND ELECTROLYTES IN MAXILLOFACIAL SURGERY

DR.VARUN MITTALDEPT. OF ORAL AND MAXILLOFACIAL

SURGERY (PG STUDENT)SRM DENTAL COLLEGE, CHENNAI

BRIEF REVIEW OFBASICS

FLUIDS – WATER, BLOOD, NS, RL, DEXTROSE

FLUID COMPARTMENTS –

INTRACELLULAR &

EXTRACELLULAR (INTRAVASCULAR,INTERSTITIAL)

ELECTROLYTES –

CATIONS (Na⁺, K⁺, Ca⁺⁺ and Mg⁺⁺) ANIONS (Cl⁻, HCO₃⁻, SO₄³⁻, HPO₄⁻,

Organic Anions and Proteins)

SOME COMMON TERMS

Homeostasis Ability of the human body to maintain the internal & external mileu for optimal function of its cells

Intracellular fluid volume (ICV) refers to the volume of fluid inside all cells, it normally contains 26-28 litre (l) out of the total 42 l of water in a 70-kg person.

Extracellular fluid volume (ECV) refers to the interstitial and the plasma volume, it contains the remaining water (14-16 kg) with most of the water in tissue fluid (ISF) and about 3 kg of water in plasma

Dextrans are polysaccharides of high molecular weight

Dehydration is a clinical condition with an abnormal reduction of one or more of the major fluid compartments

Hypernatraemia refers to a clinical condition with plasma-Na+ above 145 mM

Hyponatraemia refers to a clinical condition with plasma-Na+ below 135 mM.

Edema refers to a clinical condition with an abnormal accumulation of tissue fluid or interstitial fluid.

Hyperkalaemia refers to a clinical condition with plasma-K+ above 5 mM (mmol/L of plasma).

Hypokalaemia refers to a clinical condition with plasma-K+ below 3.5 mM.

Osmolality is a measure of the osmotic active particles in one kg of water. Plasma-osmolality is given in Osmol per kg of water. Water occupies 93-94% of plasma in healthy persons. Plasma osmolality is normally maintained constant by the antidiuretic hormone feedback system.

Overhydration refers to a clinical condition with an abnormal increase in total body water resulting in an increased ECV and thus salt accumulation

COMPARTMENTS

• Body fluid is found in

three different fluid

compartments within

the body. These are:

1. Blood plasma

2. Interstitial fluid

3. Intracellular fluid

• Number 1 and 2

above make up the

portion of body fluid

known as

extracellular fluid

DAILY INTAKE/OUTPUT OF WATER(Guyton & Hall)

NORMAL HEAVY

EXERCISE

INTAKE

Fluids ingested 2100 ?

From metabolism 200 200

Total

intake

2300 ?

OUTPUT

Insensible -- Skin 350 350

Insensible -- Lungs 350 650

Sweat 100 5000

Feces 100 100

Urine 1400 500

Total 2300 6600

ELECTROLYTES

EXTRACELLULAR –Na⁺ and Cl⁻ (main),

HCO₃⁻, Protein, Ca⁺⁺and K⁺

INTRACELLULAR –K⁺, PO₄³⁻ and Organic

anions (main) proteins, Mg⁺⁺, Na⁺, Cl⁻ and HCO₃⁻

BIOCHEMICAL MAINTENANCE

Normal Potassium requirement is 1.0 mmol/kg/day = 60 mmol/day

Normal Sodium requirement is 1.5-2 mmol/kg/day = 70-150 mmol/day

Normal water requirement is 1.5 ml/kg/h = 2.5 l/day approx

As per M² :-Water 1500 mLSodium 50-75 mmolsPotassium 60 mmols

BODY FLUID DISTURBANCES

can be classified into 3 main categories:-1. Changes in concentration (hyponatremia,

hypernatremia, hypokalemia etc.)

2. Changes in volume (hypovolemia and

hypervolemia)

3. Acid Base disturbances

CHANGES IN CONCENTRATION

HYPONATREMIA

It is defined as a plasma Na+ <

135mEq/L. It’s the most common

electrolyte abnormality. Not all patients with Na+ < 135mEq/L are

true hyponatremic patients.

◦ In conditions like hyperglycemia, hyper cholesterolemia even if the total body Na⁺ is normal, the dilutional effects of the above mentioned compounds results in PSEUDO HYPONATREMIA

HYPONATREMIA- Types & How to

identify

The volume status of the individual gives rise to 3 different clinical entities of Hyponatremia Hyper volemic Hyponatremia Hypo volemic Hyponatremia Eu volemic Hyponatremia

Thus the evaluation of a hyponatremic patient requires the measurement of Plasma osmolality Urine osmolality Urine Na+

The common factor to all the true hyponatremic patients is a reduction in the plasma osmolality below 270 mOsm/L

HYPERVOLEMIC HYPOVOLEMIC EUVOLEMIC

CCF, Nephroticsyndrome (CRF) , Cirrhosis of liver. In these conditions,urinary osmolality > plasma osmolality [conc. urine] Urinary Na⁺< 20mEq /L urine

Peripheral edema

Signs of dehydration, urinary Na differentiates, a renal from an extra renal cause. Extra Renal U Na⁺< 10 mEq/L

Dehydration Diarrhea Vomiting

Renal U Na⁺>20mEq / L Diuretics ACE inhibitors Nephropathies Mineralocorticoid deficiency Cerebral Na wasting syndrome

Patients having

endocrinological

defect SIADH &

Hypothyroidism

Only the volume

status differentiates

them from the

hypovolemic

SIADH is a

diagnosis of

exclusion

CORRECTION – WHEN & HOW?

When symptomatic

Neurological symptoms & muscle irritability seizures &

altered sensorium

Hypovolemic hyponatremia of non renal origin -

Treatment involves NS infusion to correct Hyponatremia & volume deficit

Hypervolemic hypo Na-

Treatment involves fluid restriction upto 1000ml (NS) & use of spironolactone 100mg bd or qid

Hypothyroidism -

Treatment is starting the patient on thyroxine replacement and gradual correction of sodium with saline

CORRECTION – HOW MUCH? Na⁺ deficit estimation =

(0.6 x Weight in kg)×(140 – Na⁺). Target 20 m Eq/L above actual [Na⁺] or 130 mEq/L

Rate 1 – 1.5 m Eq / L / hr or should not exceed 2 mOsm/kg/h

SIADH : Corrected by

3% NaCl

Demeclocycline 300 mg bd.

◦ Takes 1 week for onset of action

Fluid restriction – 1000 ml / day

3 % NaCl

given slow 100ml 6 hrly. Along with 1L NS.

Max rate of correction = 0.5 m Eq / hr. / Kg.

= 10 – 12 m Eq / Kg / day

ETIOLOGY & MANAGEMENT OF HYPONATREMIA

HYPONATREMIA ETIOLOGY TREATMENT

Iso-osmotic Pseudohyponatremia(hyperl

ipidemia &

hyperproteinemia, isotonic

infusions, lab error

Correct lipids and protein

levels

Hyperosmotic Hyperglycemia or

hypertonic infusions

Correct hyperglycemia

discontinue hypertonic

fluids

Hypovolemic-hypo-osmotic Renal losses : RTA, adrenal

insufficiency, diuretics

Extra renal : vomiting,

diarrhea, skin &lung loss

Na⁺ deficit replaced as

isotonic NS or RL and

treatment of underlying

cause

Euvolemic- hypo-osmotic H₂O intoxication, renal

failure, SIADH,

Hypothyroidism, analgesics

Thyroxine replacement &

Water restriction with Na⁺ &

saline correction

Hypervolemic- hypo-

osmotic

Urine Na⁺ < 10 : nephritic

syndrome, CHF, cirrhosis

Urine Na⁺ > 10 : iatrogenic

volume overload,

acute/chronic renal failure

Water restriction upto 1000

ml & use of diuretics

HYPERNATREMIA Defined as serum Na⁺ > 145 mEq/L

Neurologic symptoms - dehydration of brain cells

Lab tests – SUN & Cr, Urine Na⁺ & osmolality

An intact thirst mechanism usually prevents hypernatremia

Underlying disorders likely to cause hypernatremia are

Dehydration

Lactulose / mannitol therapy

Central / Nephrogenic DI

Excess water loss can cause Hyponatremia only when appropriate water intake is not possible. (inappropriate fluid therapy / esp. in unconscious patients )

LAB FINDINGS & TREATMENT

URINE OSMOLALITY >700 mOsm/L →

insufficient water intake, renal/extra renal water

losses

URINE OSMOLALITY <SERUM OSMOLALITY

→DI

Treat the cause.

◦ control hyperglycemia

◦ Discontinue offending drugs

DI

◦ Central DI = Desmopressin

◦ Nephrogenic DI = Fluid restriction + long term

ETIOLOGY & MANAGEMENT OF

HYPERNATREMIA

HYPERNATREMI

A

HYPERVOLEMIC ISOVOLEMIC HYPOVOLEMIC

ETIOLOGY

Admn of

hypertonic Na

solutions,

mineralocorticoid

excess

Insensible skin &

respiratory loss,

diabetes insipidus

Renal losses, git

losses, respiratory

losses, profuse

sweating &

adrenal

deficiencies

TREATMENT Diuretics Water

replacement

Isotonic NaCl,

then hypotonic

saline

POTASSIUM Normal serum K⁺ level = 3.5 to 5.1 mEq/L

HYPOKALEMIA

K⁺ level < 3.5 mEq should be treated

S- K⁺ level; of 3 mEq -> Deficiency of 250 mEq

KCl is administered at 10 mEq/L/h peripherally or 20 mEq/L/h centrally if EKG changes

Guidelines ◦ Not > 80mEq correction per day.

◦ Not > 40mEq / pint of IVF (its highly irritant)

◦ Not > 20mEq per hour of correction

HYPERKALEMIA defined as serum K⁺ > 5.1

mEq/L

It is one of the life threatening conditions

because it can cause dysrrhythmia

Treatment is aimed at driving in K⁺ into cellsTreatment Dosage Rationale

Calcium glunocate 10-30 mL in 10% sol i.v. Membrane stabilization

Sodium bicarbonate 50 mEq i.v. Shifts K⁺ into

Glucose- insulin 1amp D50 with 5U n-

insulin

Shifts K⁺ into

Sodium polysterence 50-100g enema+50 mL

70% sorbitol & 100 mL

water

Remove excess

Dialysis Removes excess from

serum

Calcium Normal Ca⁺⁺ conc is 8.8 to 10.5 mg/dL

HYPOCALCEMIA ( Ca⁺⁺< 8 mg/dL[SI: 2mmol/L])

Peripheral & perioral paraesthesias

Carpopedal spasm(Trousseau’s sign)

+ve Chvostek’s sign(facial nerve twitch)

Lethargy & irritability

Abdominal pain & cramps

Prolonged QT interval on ECG

Generalized seizures, tetany, laryngospasm

Emergency (Acute)◦ 100 – 200mg elemental Ca⁺⁺ IV over 10mts in 50 to 100ml

5D ◦ followed by 1-2mg / Kg / hr infusion 6-12hrs.

NON Emergencies ◦ Oral Ca supplements◦ Vit D₃

HYPERCALCEMIA ( Ca⁺⁺>12mg/dL [2.99mmol/L]

Anorexia, nausea, vomiting, polyuria

Constipation, abdominal pains, renal colic(stones)

Fatigue, hypotonia, lethargy, coma

Shortening of QT interval on ECG

Treatment usually emergency & aimed at ◦ bone resorption – 1

◦ bone deposition – 2

◦ GIT Absorption – 3

◦ renal clearance – 4.

Furosemide(Lasix 40 mg with NS at 300-400mL/h) diuresis 4

Corticosteroids -1,3

Bisphosphonates – 1

IV phosphates – 2

Consider hemodialysis

Mithramycin( 25μg/kg/ i.v. over 2-3 hrs as last resort)1

MAGNESIUMHypomagnesemia (Mg⁺²<1.5 mEq/L)

Etiology-◦ simulate hypocalcemia

◦ In fact, hypomagnesemia must be ruled out in any case of refractory hypocalcemia or hypokalemia

Commonest cause is nutritional / debilitating disease/ patient on

TPN

Clinical presentation- Symptoms of hypocalcemia+

Tremors, vertigo, convulsions, ventricular ectopy

TreatmentOral – MgO 400 – 3200mg/day . This can cause diarrhea.

Parenteral – 1 to 2g MgSO₄ repeated 4-6 hrly.

Hypermagnesemia (Mg⁺²>3 mEq/L)

Etiology-Rare, mostly iatrogenic – overzealous correction

Clinical presentation-Respiratory depression, hypotension,

cardiac arrest, nausea, vomiting,

hyporeflexia, coma.

Treatment- Ca gluconate 15mg / Kg over 4 hrs. Calcium acts as direct

Mg antagonist.

Consider dialysis

PHOSPHATENormal level – 2.5 to 4.9 mg/dL

Hypophosphatemia (Po₄³⁻< 2.5 mg/dL)

Clinical presentation-( seen in <1mg/dL)

Lethargy, hypotension, irritability,

cardiac arrhythmias, skeletal demineralization,

hemolysis, paraesthesia

Treatment-

Neutra-Phos or K-Phos 1-2 tabs (250mg PO₄ bid) for mild cases

K-Phosphate 0.8-0.24 mmol/kg i.v. 8 hrly for severe cases

Hyperphosphatemia ( PO₄>4.5 mg/dL)

Etiology-Hyperphosphatemia occurs primarily due to

defective renal clearance ; and goes hand in hand

with hypocalcemia.

Clinical picture-Metastatic calcifications

Hypocalcemic symptoms

Management-Treatment of primary cause (RF)

CRF – dialysis

Chelation – Ca CO₃

FLUID THERAPY…The Goal of fluid therapy is to correct

hypovolemia with Isotonic or Hypertonic

Crystalloids, Colloids or Blood products.

Establishment of a u/o >0.5 ml/kg/hr and a

return of peripheral perfusion are good

indicators of circulating volume.

Achieved by maintaining fluid input required

under normal circumstances + Replacing the

deficit occurred peroperatively + Matching on

going losses.

The administration of intravenous replacement

fluids restores the circulating blood volume and

so maintains tissue perfusion and oxygenation.

Continue…

To replace abnormal losses of blood, plasma

or other extracellular fluids by increasing the

volume of the vascular compartment, principally

in:

Treatment of patients with established

hypovolaemia: e.g. haemorrhagic shock

Maintenance of normovolaemia in patients with

ongoing fluid losses: e.g. surgical blood loss.

AVAILABLE REPLACEMENT FLUIDS, COMPOSITION

& CHOICE…

Crystalloids having Molecular Wt < 8000 and low oncotic pressure; eg. Normal saline(NS), dextrose 5%, 4%, Hartmann's solution(sodium lactate)or LR

Colloids having Molecular Wt >8000 and high oncotic pressure; eg. Dextran, gelatin (Gelofusine, Haemaccel, Hespan)

Blood products - Whole blood, fresh frozen plasma, albumin solution, ConcFactors, Platelets

Composition of Crystalloids…Fluid Glucose

g/L

Na⁺ mmol K⁺ mmol Cl⁻ mmol Kcal/L

D5W(5% to

50%

Dextrose in

water)

50 to 500 --- --- --- 170 to 1700

NS(0.9%

NaCl)

--- 154 --- 154 ---

D5NS

(0.9% NaCl)

50 154 --- 154 50

D5LR(5%

dextrose in

RL)

50 130 4 110 180

Lactated

Ringer

--- 130 4 110 <10

1/2NS to

1/5

NS(.45% to

.19% NaCl)

--- 77 to 31 --- 77 to 31 ---

Are excluded from the intracellular compartment

because the cell membrane is generally

impermeable to sodium.

Cross the capillary membrane from the vascular

compartment to the interstitial compartment.

Are distributed through the whole extracellular

compartment.

Normally, only a quarter of the volume of

crystalloid infused remains in the vascular

compartment, therefore AS A RULE:

To restore circulating blood volume

(intravascular volume), crystalloid solutions

should be infused in a volume at least three

times the volume lost.

CRYSTALLOIDS...

Lactated Ringer’s Solution:- Sydney Ringer,

London physician in 1882 (“balanced” salt sol)

Alexis Hartmann in 1930, introduced Na-

lactate, hence named Lactated Ringer or

Hartmann’s sol in England

Formulated with an electrolyte composition

same as plasma, Lactate provides buffering

capacity

Metabolized in liver and kidney to pyurvate & finally to HCO₃⁻+CO₂+H₂O or toHCO₃⁻+glucose with an ↑ in plasma glucose

of 50 to 100 mg/dL.

Normal Saline (NS) is mild hypertonic. No Ca⁺², so preferred as a diluent for tranfusedblood, as no chance of interference with citrate anticoagulant.Used less frequently for resuscitation from hemorrhagic shock.

Plasmalyte-A isotonic crystalloid similar to LR, but without Ca⁺² and acetate and gluconate instead of lactate.Developed for use in resuscitation and designed to be compatible with transfused blood products.Contains Mg⁺² offers advantage as less acidic and closer to plasma osmolarity

COLLOIDS…As they tend to remain within the vascular

compartment they require smaller infusion volumes

than crystalloids. They are usually given in a volume

equal to the blood volume deficit.

Mimic plasma proteins, thereby maintaining or

raising the colloid osmotic pressure of blood

Provide longer duration of plasma volume

expansion than crystalloid so require smaller

infusion volumes.

Supplementary infusions will be needed to maintain

blood volume in conditions such as:

Trauma, Acute and chronic sepsis, Burns as

capillary permeability is increased, they may leak

from the circulation and produce only a short-lived

volume expansion

COMPOSITION OF COLLOIDS…Fluid Na⁺ K⁺ Ca⁺² Cl⁻

Colloid

Osmotic

Pressure

Albumin 5% 130-160 <1 V V 27

Gelatin

(Gelofusin)

154 <0.4 <0.4 125 34

Hydroxyethy

l Starch 6%

154 0 0 154 28

Dextran 60

(3%)

130 4 2 110 22

Gelatin

(Haemaccel

)

145 5.1 6.25 145 27

Ionic

composition

of n-plasma

135-145 3.8-5.1 2.2-2.6 100-110 27

COLLOIDS…Albumin 5% most commonly used colloid in

American Trauma care, rapidly expands plasma volume, also associated with few side effects and toxicities

In patients with total body fluid overload and hypoalbuminemia (1⁰) may benefit from 25% albumin.

Starch solutions prepared by adding polymers of amylopectin to simple saline(Hespan) or to a balanced salt sol (Hextend), later being more hemostatic in some trials is becoming common choice in American Practice. They may cause coagulopathy at dose >20mL/kg or after about 1500 mL of total fluid admn.

Dextrans are glucose polymers can be used alone as a colloid volume expander or in combination with Hypertonic Saline.

Carries disadvantages like-They carry von-Willebrandlike effect on platelet function, also associated with HS reactions and impaired renal functions.

Hypertonic Saline with or without adding dextranshas been studied extensively and a mixture of 6% dextran 70 with 7.5% HS has been approved in several European countries. Provides advantage as it adds “small volume” (4ml/kg) when infused. This has

made HS popular choice for fluid resuscitation.Mattox et al. showed in 1991 that prehospital HSD

resulted in a survival benefit in severe injuries and ↓ infection chances.

Coimbra et al demonstrated that HS resuscitation ↓ the susceptibility to sepsis following hemorrhagic shock.

Crystalloids Vs Colloids Advantages include- Few side-effects Low cost Wide availability Efficacious

Disadvantages include- Short duration of action Required in large quantity Lack of O₂ carrying

capacity May cause oedema Weighty and bulky

Advantages include- Longer duration of action Less fluid required to

correct hypovolaemia Less weighty and bulky

Disadvantages include- No evidence that they

are more clinically effective

Higher cost May cause volume

overload May interfere with

clotting Risk of anaphylactic

reactions

BLOOD PRODUCTS…Transfusion with whole blood is rarely indicated,

as component therapy allows specific

deficiencies correction, allows longer storage

and reduces the risk for transfusion reactions.

However, even where quality standards are very

high, transfusion carries some risks. If standards

are poor or inconsistent, transfusion may be

extremely risky.

Blood products include- Packed RBC’s

Platelets

Fresh frozen plasma and Factor VIII, IX

Cryoprecipitate

Plasma protein Fractions

Packed Red Blood Cells…150–200 ml red cells from which most of the plasma

has been removed

Hemoglobin approximately 20 g/100 ml (not less than

45 g per unit) & Haematocrit 55%–75%

Indications: ◦ Preoperative anemia <9g/dl,

◦ Active bleeding, with sign & symptoms of hypovolemia

unresponsive to crystalloid or colloid infusions,

◦ Prophylactic transfusion to prevent morbidity from anemia at

greater risk for tissue hypoxia

◦ Replacement of red cells in anemics and also with crystalloid

replacement fluids or colloid solution in acute blood loss.

Red cell suspension are prepared by adding ±100 ml

normal saline, adenine, glucose,mannitol solution to

achieve better flow rates.

Platelets…Prior to surgical and major invasive procedures

when the platelet count is <50000 μL Prevention or treatment of non surgical bleeding

due to thrombocytopenia and Platelet function

defects

Patient with accelerated platelet destruction with

acute blood loss.

One unit of platelets will increases platelet count

5000-10,000/mm3

Dose 1 unit of platelets per 10 kg body weight

Intraoperative bleeding increases with counts of

40,000-70,000/mm3, and spontaneous bleeding

can occur at counts <20,000/mm3

Fresh Frozen Plasma… Contains normal plasma levels of stable clotting factors,

albumin and immunoglobulin

Factor VIII level at least 70% of normal fresh plasma level

250 cc/bag(1 unit); contains all coagulation factors except

platelets Dose→10-15 mL/kg ↑plasma coagulation factors to 30% of

normal; fibrinogen levels ↑by 1 mg/mL of plasma

transfused; acute reversal of warfarin requires 5-8 mL/kg

of FFP. ABO compatibility is mandatory

Replacement of multiple coagulation factor deficiencies:

e.g.

— Liver diseases

— Warfarin (anticoagulant) overdose

— Depletion of coagulation factors in patients receiving

large

volume transfusions

Cryoprecipitate…

Prepared from fresh frozen plasma by

collecting the precipitate formed during

controlled thawing at +4°C and

resuspending it in 10–20 ml plasma

10-20 mL/bag(1 unit); contains 80-100

iu/pack factor VIII, 100 iu/pack factor vWF,

60 iu/pack factor XIII, and 150-300 mg/pack

fibrinogen

Indications include hypofibrinogenimia, von

Willebrand disease, DIC with depleted XIII

and fibrinogen

Eye to the future

1. Better Monitors- Access severity of

ischemia. Near-infrared tissue spectrometry

currently used in trauma center in ICU in

US.

2. Improved Hemorrhage Control- Locally

applied thrombotic agents(fibrin sprays,

thrombin bandages) systemic

procoagulants( fac VIIa will ↓ period of active hemorrhage

3. Better Fluids- Blunting Perfusion Injury- Ringer’s Ethyl Pyurvate solution & pentoxifylline

Ringer’s Ethyl Pyurvate solution- 3-C carboxylic acid, pyurvic acid integral intermediary metabolism of glucose & some amino acids. Pyurvate has advantages as a resucitation fluid but fairly unstable. Sims et al (Care Med 2001; 29: 1513-1518)found that ethylated pyurvate is stable & much more soluble in RL.

Pentoxifylline- a methlxanthine derivative is reported with several advantages. Improved cardiopulmonary function in septic shock patients and its been formulated that hypertonic PTX (HSPTX), as opposed to RL, would attenuate end-organ injury without compromising hemodyanmic.

VOLUME CORRECTION1. In Dehydrated individuals (severity)

2. In Normal recovering healthy adult (ideal)

3. According to type & rate of fluid loss

including-

Trauma, Haemorrhagic shock, Burn

4. In Pediatric patients and elderly patients

5. In special conditions including-

Renal failure, Liver Failure, Factor

deficients,

GA contraindication

IMPORTANT POINTS TO REMEMBER…The PROTEIN SPARING EFFECT is one of the goals of

basic i.v. therapy. Admn. of glucose at least 100 mg/day ↓↓ Protein loss by more than half.

Success of Fluid Replacement is monitored by-

a) Fall in pulse

b) Rise in BP

c) Restoration of urine output

Vascular compartment is the most accessible compartment followed by interstitial & ICC

ECF maintains shorterm regulation of BP, maintains BP & its osmolarity prevents swelling and shrinkage of cells (change in ECF Vol. can ↑ or ↓ BP)

Total Na⁺ load(qty. of Na⁺ and not conc.) in ECF determines the total amount of H₂O that will be osmotically retained.

IMPORTANT POINTS TO REMEMBER…Maintenance fluid therapy is affected by-

1) Age (generally increased in children &

reduced in

old age)

2) Weight ( less in obese patients)

3) Significant fever ( Should be increased by

10%

for each degree centigrade >37⁰ C)

4) Hyperventilation & high

temperature(increased)

5) Reduced in- Hypothermia, some instances

of

IMPORTANT POINTS TO REMEMBER… Fluid replacement should, if possible, match

the volume and composition of fluid lost.

The goal of fluid therapy is to correct

hypovolemia with crystalloid, colloid or blood

products.

Establishment of a urine output >0.5 mL/kg/hr

and a return of peripheral perfusion are good

indicators of circulating volume.

IN DEHYDRATION STATE… Loss of fluid from ECF compartment produces

clinical picture commonly k/as Dehydration.

Clinical Picture-

Intravascular → Pulse pressure is↓, Tachycardia

Extracellular → Eyeball turgor ↓

Intracellular → Skin turgor at forehead/ sternum

Classification & Assessment Management

Type Age Clinical presentation

MILD

5% Wt loss

O to 6 yrs – 5%

6 or more – 4%

Alert, Tears Normal, Thirst,

mild oliguria,

no detectable physical

signs

MODERATE

5-10% Wt loss

0 to 6 m – 10&

6m to 6 yrs – 7.5%

6 or more – 6%

Lethargic, Dry mucus membrane, Tears ↓, Marked thirst, oliguria,

tachycardia, slightly sunken

eyes

SEVERE

10% or more

Wt loss

0 to 6 m – 15%

6 to 6 yrs – 10%

6 or more – 8%

Loss of skin tone &

tissue turgor, Tears

absent, Mucus membrane

cracked, cold clammy

skin, Tachycardia,

sunken eyes, severe

oliguria or anuria,

Management…Mild to moderate: ORT at 5 mL/min. If evidence

of bowel obstruction, ileus, or acute abdomen exists, then intravenous rehydration is indicated at 20-30 mL/kg (isotonic NaCl sol over 1-2 h).

Severe: 1) Initial management i.v. rapid admn. of 20 mL/kg of RL or isotonic NaCl sol.(500mL in 15 min, 500mL in next 45 min, 500mL in next 1hr)2) Phase 2 focuses on deficit replacement,

provision of maintenance fluids, and replacement of ongoing losses. 4, 2, 1 formula is used:for first 10 kg, 4ml/kg/hfor next 10 kg, 2ml /kg/hfor each additional kg, 1ml/kg/heg. 55 kg male 40ml+20ml+35ml=95ml/kg/hr

The patient is evaluated at the end of 2 hrs.

Always look for JVP / Basal rates / CVP if

available.

If rehydration is on correct lines, one can find u /o

increasing. If u/o doesn’t rise even with 2/3 volume

replacement, one can try (10 – 20)mg Furosemide

to r/o prerenal renal failure. If there is no response to diuretics, one should not

hesitate to start 5u /Kg/min of dopamine. If the kidney

doesn’t open up even with this, the patient has most

probably gone into intrinsic renal failure.

A good urine output is an indirect indicator of

adequacy of circulation.

In course of rehydration, if u/o > 1ml / kg / hr., patient

can be taken up for anesthesia.

Normal Healthy Patient…(Ideal example)Maintenance or Base line Fluid requirementsBest to stick to usual 2 to 3 liters & not challenge

the kidney.According to KG formula a 70 kg male requires

about 120mL/hr infusion rate of D51/5NS with 10 mmol KCl/Pint(500mL)

This will deliver about 3 liters of free water/day.Role of NS (0.9%) → Major ECF cation and

constitutes nearly for 50% tonicity which is 300 mOsm/L normally.

Role of Dextrose 5% → To provide a tonicity similar to plasma, sugar metabolizes & free water remains & gets distributed.

K⁺ is added as it is intracellular & not readily available

If NS is given separately than balanced

solutions can be admn. alternatively.

NS (0.19% to 0.9%) with Dextrose 5% or

Dextrose 5% with Lactated Ringer solution.

Urine output consideration-

Oliguria is common during immediate post-op

period (mostly adrenal cortex response to

stress, ↑ in ADH and aldosterone is released in first 24 hrs and Na⁺ and water are retained. Also GA→ Renal blood flow↓ and GFR)

Persistent oliguria(less than 20mL/hr) related to hypovolemia

TPN (total parentral nutrition)…

Can meet complete calorific demand

Associated with technical difficulties.

If enteral feeding cannot be started for

3 PODs, TPN must be begun to meet

energy demands.

Type & rate of fluid loss including-

Trauma, Haemorrhagic shock, Burn…

Trauma can be Road Traffic Accident or

Surgical.

Management of Circulatory disorder comes

after Airway and Breathing management

Vitals Sign assessed include- Appearance of the patient

Mental status

Pulse rate (>120 mm Hg in adult)

Blood pressure

Capillary refill (blanch test) & Skin

perfusion(Grade III and Grade IV)↓Urine output due to ↓intravascular volume

CLASS I CLASS II CLASS III CLASS IV

Blood

Loss(mL)

UP to 750 mL 750-1500 mL 1500-2000 mL >2000 mL

% Blood loss Up to 15% 15-30% 30-40% >40%

Pulse rate <100 >100 >120 >140

Blood Pressure Normal Normal Decreased Decreased

Pulse Pressure Normal Decreased Decreased Decreased

Respiratory

Rate

14-20 20-30 30-40 >35

Urine output

ml/h

>30 20-30 5-15 Negligible

CNS/mental

status

Slightly

anxious

Mildly

anxious

Anxious,

confused

Confused,

lethargic

Fluid

replacemnet(3:

1)

Crystalloid Crystalloid Crystalloid &

Blood

Crystalloid &

Blood

Laboratory Work up… Ability to rapidly measure Hb, arterial blood gases and

serum lactate level is essential to any trauma center.

Serum Lactate level and base deficit are both good

early measures of the depth of shock, and are currently

the best single markers available for the adequacy of

resuscitation.

Base deficit is calculated from the measured arterial PCO₂ and pH. Hb may vary but may be kept maintained at 8-10mg/dL.

Pressure measurement- Placement of an arterial line early during fluid resuscitation is strongly adviced. Urine output- ↓ with ↓ renal perfusion. Prolonged duration

indicates renal system failure TEE- Best available test for assessing volume status and

cardiac function(directly reveals contractility also) CVP Monitoring is helpful if no underlying cardiac disease.

Adequate Intravenous Access…Resuscitation depends on the ability to deliver

fluids to the intravascular space.

Current ATLS protocol recommend the

immediate placement of Two Large-bore(16 gauge

or more) peripheral IVs in any patient in

hemorrhagic shock. If not than Subclavian vein is

most common choice although femoral vein

placement is easier.

Fluid therapy matches with severe dehydration

therapy. As per ATLS manual LR is the first choice and NS is

the second choice.

Plasmalyte-A designed to be compatible with blood

products

Lactated Ringer’s given 2L rapidly in 10-15 min

(20mL/kg for child)in case of prolonged

hypovolemic shock and then observed.

If no rise in BP upto 80-100 mm Hg, additional

fluid is given with blood with control of loss.

Initially O -ve blood(urgent), Type specific

blood(5-15 mins), then cross matched (30 mins).

Fresh Frozen Plasma(FFP) is used as volume

expander, also provides clotting factors. As a

rule, FFP is given after every 4U to 5U of blood,

especially if PRBC’s are administered. Hextend

generally used.

Platelet is administered if the count is

<100,000/mm³

Still A Controversy…(Literature discussed)Various studies include-Kramer et al;(1989) Trauma patients should be

resuscitated with crystalloids, whereas colloids are effective in nonseptic, nontraumatic elective cases.Choi et al;(1999) found out lower mortality rate in

trauma patients who received crystalloids compared to colloids.Cochrane group et al;(1998) in a study on 1419

patients found that albumin resulted in 6% increase in the absolute risk of death compared to patients who received only crystalloids. SOAP(Sepsis occurrence in Acutely Ill

patients) study;(2005) Done in Europe concluded that albumin administration resulted in generally worse outcomes at 30 days, especially in trauma cases.

U.S.MILITARY TACTICAL COMBAT CASUALTY CARE

GUIDELINES FOR FLUID RESUSCITATION…

Adopted guidelines for fluid resuscitation in the

field based on the logistical advantages of

Colloid solutions (Less volume to transport).

Condition Recommended

treatment

Controlled hemorrhage No fluids

necessary

without shock

Controlled hemorrhage Hespan 1000 cc

with shock

Responses to Initial Fluid Responses…

Parameter

evaluated

Rapid response Transient

response

No response

Vital Signs

Return to normal

Transient

improvement,

Recurrece of ↓ BP & ↑ HR

Remain abnormal

Estimated Blood

loss

Minimal 10-20% Moderate and

ongoing 20-40%

Severe >40%

Need for more

crystalloid

Low High Very High

Need for Blood Low Moderate to high Immediate

Blood preparation Type & crossmatch Type-specific Emergency blood

release

Need for operative

intervention

Possibly Likely Highly likely

End Parameters of Volume Resuscitation…Primary goal is the restoration of Oxygen into

the vital organs to sustain aerobic

metabolism. (Cardiac output and Hb% are

major determinants)

Goals of volume resuscitation-

Cardiac index >3L/min/m²

Oxygen uptake (Vo₂) >100mL/min/m²

Serum lactate < 4 mmol/L

Base deficit -3 to +3 mmol/L

Central venous pressure=15mm of Hg

In BURN…If burn area >15% in adult and > 10% in child

Parkland formula: Total fluid required during

the first 24 hours is as follows-

Fluid required=

(%body burn)(body wt)4 ml

Replace with LR solution over 24 hours, as

½ total over first 8 hrs(from time of burn)

¼ total over second 8 hrs

¼ total over third 8 hrs

Rule of Nines is followed

In Pediatrics… According to formula- Ist 10 Kg 100ml/kg/day = 4ml/kg/hour 2nd 10 Kg 50ml/kg/day = 2ml/kg/hour Each Kg 20ml/kg/day =1ml/kg/hour

M² Method- 1500ml/m²/dayAssessment of a child- Capillary refill, pulse rate, blood pressure, skin tone State of fontenelle, sunken eye, dry mouth Specific gravity of urine (eg. 1.030 highly conc.) Weight loss if possible

Difference in management- Precise administration of the level of electrolytes After major surgery or trauma ↓ requirements because

fluid retention is promoted.( 1st day 50%, 2nd day 75%)

A WORD OF CAUTION…

Plasma should never be used as a

replacement fluid.

Plain water should never be infused

intravenously. It will cause haemolysis

and will probably be fatal.

Dextrose (glucose) solutions do not

contain sodium and are poor

replacement fluids. Do not use to treat

hypovolaemia unless there is no

alternative.

Some Special Situations… [ARF]

Acute Renal shutdown refers to NIL urine output.

Hence the fluid requirement is only to balance the insensible loss. Which amounts to 750ml / 70Kg / 24hrs.

This volume is replaced as ½ NS with 5D solution ( 5% Dextrose with 0.45% NaCl )

During the recovery phase when the patient produces urine, RL can be used in a volume of ( 30 + previous hour’s urine output) in the next hour.

Fluids in Liver Failure…

Fluid replacement during Ascitic tapping

◦ No definite guidelines

◦ During replacement, observe neck veins and

auscultate for basal rates.

◦ fluid of choice is colloids – HES, Gelatin, FFP

Advisable to have a CVP line in any case

of laparotomy and it should guide fluid

administration

Every third pint of fluid should be a colloid

Blood loss Related Issues… In a patient with normal Hb. (> 12 gm), there

is no need to replace blood loss by transfusion; if loss is < 20 % of circulating blood volume( 70 ml / Kg bwt)

To maintain BP, twice the volume of blood loss is given as crystalloids apart from the 10ml / kg / hr. maintenance.

If Hb < 10 gms, any blood loss to be replaced by transfusion.

Throughout surgery keep an eye on. u/o, neck veins & capillary filling time.

Determing i.v. rate

For a MAXI drip- 10 drops/ml used

thus 10 drops/min = 60ml/h or

16 drops/min = 100ml/h

For a MINI drip- 60 drops/ml used thus 60 drops/min = 60 ml/h or

100 drops/min = 100ml/h

References

Clinics Of North America Vol 18, No1,

Feb 08

Bailey & Love’s Short Surgery of

practice

Fluids & Electrolytes in the Surgical

Patients by- Carlos Pestana

Trauma –ER & Surgical Management

–

William C. Wilson