DR. PRAMILA BAJAJ SR. PROF. & HEAD

DEPTT. OF ANAESTHESIA, ADDITIONAL PRINCIPAL, RNT MEDICAL COLLEGE, UDAIPUR (RAJ.)

Perioperative Fluid Management

www.anaesthesia.co.in anaesthesia.co.in@gmail.com

Perioperative Fluid Management

1. Fluid & electrolyte management paramount in

surgical patient.

2. Change in Fluid (Fl.) & Electrolyte (El.) Composition

Pre.op

Post op.

In response to trauma and sepsis

Distribution of Body Fluids

• Helps us understand the subject.

• Total body water : 50-60% of total body weight.

• Relationship constant for an individual; reflection of body fat.

• Water in muscle & solid organs > Water in fat & bones young, lean adults – greater% of TBW than elderly / obese.

Av. young adult male : 60% water of TBWt

Av. young adult female : 50% water of TBWt, b/c of high adipose / fat.

• Estimates of TBW Up by 10% in malnourished

Down by 10-20% in obese.

• New born infants : 80% water of TBW Decreased to 65% by 1 year, then constant.

Distribution of Body Fluids

Fluid Compartments• Total Body Water - Extracellular Fluid (20%);

Intracellular Fluid (40%), • TBW – ECF = ICF

Normal Water Balance

How body maintains its water volume?How body maintains its water volume?

Kidneys : A major role.

Oral / iv fluids & urine output : Important parameters of body fluid balance.

Insensible fluid input = 300 ml water due to oxidationinsensible fluid loss = 500 ml through

skin (400 ml through lung & 100 ml through stool)

Fluid loss – Fluid input = 1000 – 300 ml = 700 ml• Insensible loss in : Fever, Hypermetabolism,

Hyperventilation• Sweating : Active process : Loss of electrolytes & water1. Moderate sweating : 500 ml2.Severe Sweating

High fever 3. Burns

Abd. Surgery

1000 – 1500 ml

500-3000 ml

• Kidney must excrete about 500-800 ml urine /

day (irresp. of oral intake)

• Daily Sodium intake : 3-5 gm/d.

• Balanced achieved by kidneys :

In hyponatremia : Salt excreted <1 mEq/d

In Salt wasting kidneys: >5000 mEq/d.

Normal Water Balance …………

Composition of Fluid Compartments

ECF compartment : Balance between electrolytesECF ICF

Principal Cation : Na+ K+, Mg2+

Principal Anion : Cl- & HCO3- Phosphate & Prot.

ATP drivenNa K Pump

ECF ICFConc. grad.

Imp. Points to Remember :

1. Proteins : important contributors to Osmolality

2. Movement of water across compart. is free but that of

proteins and ions restricted.

3. Even distribution of water in all compartments.

4. Sodium confined to ECF because of osmotic &

eIectrolyte properties

5. Sodium containing fluids distributed in ECF

Vol. of IV and interstitial sp. as much as 3 times of

plasma.

Definitions1.1. What is Osmotic pressureWhat is Osmotic pressure??- Movement of water across

C.M. depending primarily upon osmosis.

- Determines distribution of water among different fluid compartment. (ICF & ECF)

- generated by solution proportional to no. of particles / unit volume of solvent.

- does not depend upon type, valence and weight of the particles

To generate O.P. Solute must be unable to cross C.M.

Unit osmoles (osm) or milliosmoles (mosm).

E.g.. : One mmol of Nacl 2mosm (one each from Na+ & Cl-)

2. Osmolality

• Determined by amt. of solute diss. in a solvent (water)

measured in wt (kg)

Determinants: Conc. of sodium, glucose, urea (BUN)

Calculation :

Serum osmolality = 2Na+ + Glucose + BUN

18 2.8

• Osmolality of ECF and ICF b/w 290-310 Osm in each

compartment

Define Osmolality, Effective Osmolality & OsmolarityDefine Osmolality, Effective Osmolality & Osmolarity

3. Effective Osmolality

• Determined by solutes which do not freely permeate cell

wall and hold water within ECF

Effective Osmolality = 2xNa (mEq/L) + Glucose (mg/dl)/18

• Glucose accounts for only 5 mOsm/kg in effective

osmolality. plasma Na concentration is the

determinant of the plasma osmolality.

4. Osmolarity : Determined by amt. of solute dissolved in

a solvent (water) measured in vol. (litre).

• Concentration of solution of a solute diss. in 1 litre of

solvent is expressed as mOsm/L.

Concentration of Electrolytes : Expressed in terms

of chemical combining activity or equivalents.

Univalent ion (Sodium) ; 1 Meq = 1 Mmol

Bivalent ion (Mg) ; 2 Meq = 1 Mmol

Equivalent of an ion = Atomic Weight (gm)

Valence

Paediatric Surgery

1. Fluid Management : A critical element in paed. surgery b/c infants & children sensitive to even small degree of dehydration Higher requirement for water & electrolytes / KgBw.

Inability to excrete water load due to immature kidneys Overload.

2. Complex surgical procedures Rapid change in fluid requirement Frequent assessment and modification of fluid therapy.

How are infants and children different How are infants and children different from adults?from adults?

3. In O.T. rapid change in req. during:- Conduct of Anaesth. & Surg.- Change in temperature- Metabolism & vol. shift (due to

trauma, hemorrhage, tissue exposure) Intracompartmental fluid shift

4. Requires fluid replacement with sol. to compensate for energy, water, protein & electrolyte losses.

5. Anaesthetist : Alert for - obvious fluid loss - Hidden fluid loss (insensible loss) - Third Space loss

Paediatric Surgery …………

Physiological Considerations

• Proportion of ECF/ICF change with age.

• Body cells, surrounding fluid in electrical equilibrium

• TBW Vol. & Fluid exchange rate vary

with age.

• Before birth, nutrition demands met

through placental transfer. NFT

infant - enough fluid reserve to last

till full oral breast feed.

Physiological Considerations … …..

TBW Fat

28 wk (1kg) 80% 1%

Term 70-75% 17% ECF (30-40% of TBW) gradual shift

3 mths (6kg) 70% 30% Further in ICF; ECF<ICF

1 Year 60% ECF to 27%

Immature Infants : Higher% of TBW and ECF Total blood volume of a newborn infant 8.5% of B.W.

ECF

Intravascular Plasma Vol.

Together contribute

Interstitial Fluid Vol.

Functional Extracellular Fluid

Vol. [FEFV]

ECF also includes III space / transcellular fluid which is physiologically non-functional

Interstitial Space

fluid filteredHigh cir. vol. : Vas. Comp. interstitial sp. (reservoir)

fluid filteredLow cir. vol. : Interstitial sp. Vas. comp. buildup

circulatory vol.

Adolescence: FEFV 27-30% [Inter. space vol. + Plasma vol.]20% + 7-10%

Full term infant : FEFV 45%

What is the importance of transcellular (III Sp.) fluid?What is the importance of transcellular (III Sp.) fluid?

• Non functional extracellular fluid• Unavailable pool of water formed by transudation

from cells and EC space• E.g. Fluid within GIT formed during-

Int. Obst.

Ascitis

Urine

Pleural effusion• Fluid in III space loss

from FEFV• Fluid preferred for replacement : Ringer lactate

Intracellular Fluid

• Isotonic Solution Cell Vol. constant due to free

movement of water from within cells

• Hypotonic Solution Inward water movement

Increased cell volume

• Intracellular fluid bound to protein

• Energy required for Potassium (inside cell) &

Sodium transport (outside cell).

Describe the renal physiology in neonates.Describe the renal physiology in neonates.

• Postnatal shift in body fluid med. by Na+ and H2O excretion by immature kidneys.

• Sodium and water excretion by immature kidneys Postnatal: Mediated by shift in body fluid

• Urine Vol. 1st day – 0-68 ml7th day – 40-300 ml

• At birth GFR 25% of adult rate (20 ml min-1 1.73m-2)• Rapid in 2 wks; slower to adult rate by 2 yrs of age• Infants can handle twice the (N) vol. load b/c -ve effects of

low GFR compensated by +ve effects of low concentrating & high diluting capacity

Add conc. capacity of infant well below adult.

Concentrating capacity : (Max. osmolality 500-600 (well below adults) Osm/kg) in response to water

Adult : (1200 mOsm/ kg)Diluting capacity : low in dehydrated infantsIf water loaded diluting capacity well above adults

(Osmolality 30-50 mOsm/kg)• Fasting newborn (72 hours) Minimum elevation of

BUN & Na. (Loss of BW 13%).• 8% decrease in BW; Neg. N2 balance even when fluid

given at 50ml/kg/day/ or unlimited amt. of breast milk.• Milk feed Positive N2 balance & weight gain

Wilkinson et al. 1962, Lancet 1983

Renal Physiology in Neonates …….

Electrolyte Physiology

Sodium Physiology : Variable therefore inaccurate indicator of hydration.

• Daily requirement (Term infant) 2-5 meq kg-1 day-1

• Term infants retain Sodium when in negative Na balance like adults.

cap. to excrete Na when in positive balance.• Ac. change in balance Gross variation in blood

pressure, Intracerebral hemorrhage. • PPV & use of PEEP ed Natriuresis, ed vasopressin,

ed water retention

Daily Electrolyte Requirements for Paediatric patients

Patients wt >10 kg Patients wt <10 kg

Sodium 20-150 meq 2-5 meq/ kg

Potassium 20-240 meq 2-4 meq/ kg

Acetate 20-120 meq -

Chloride 20-150 meq -

Calcium 5-20 meq 0.5-3 meq/ kg

Phosphorus 4-24 meq 0.5-1.5 meq/ kg

Magnesium 4-24 meq 0.25-1 meq/ kg

What are the special features of CVS physiology What are the special features of CVS physiology in infants?in infants?

• Immature myocardium & S.N.S. Propensity to hypovolaemia greater in neonates / infants.

• [Myocardial contractility + vas. tone & compliance] less variable tachycardia Pri. comp. mech. during vol.

• Excess HR C.O. • Anaesth. effect Further depression of myocard.

Hypovolemia exaggerated maintenance of effective vas. vol. in paed. patient essential to sustain circulatory function and vital organ perfusion in peri-op. period.

Hepatic Function

Hepatic function immature

• Carbohydrate reserves accumulate in last TM of

pregnancy : limited stores in pre-term neonates.

• Most pre-term neonate : Require 10% dextrose

infusion to prevent hypoglycemia in early perinatal

period.

Hepatic Function ……….

Clinically significant hypoglycemia :

Full term neonate : < 30 mgdl-1

Pre term infant

First 3 days < 20 mgdl-1

After 3rd day < 40 mgdl-1

Treatment : Ac. hypoglycemia : Bolus 0.5-1.0 g/kg-1 iv glucose followed by infusion 5-6 mg kg-1 as maintenance infusion

Monitor serial blood glucose.

Response to surgical trauma : Catechol.

glucocort.

blood glucose.

Hypoglycemia : - Unusual during preop. fasting in children

- Uncommon during surgery.

- Not easily recognized during anaesth.• Dextrose in patient with prolonged fast prevents ketosis,

protein catabolism post operatively.• Continue glucose inf. commenced in OT until patient

awake and oral intake established.

Hepatic Function ……….

What are the fluid management protocols in What are the fluid management protocols in infants ?infants ?

Divided into 3 phases :

a) Deficit therapy

b) Maintenance therapy

c) Replacement therapy

Deficit Therapy : Management of fluid / electrolyte loss prior to surgery :

Three components

1) Estimate Severity of dehydration

2) Determine fluid deficit

3) Repair the deficit

Assessment of dehydration severity in neonates & infants

Signs & Symptoms Mild Moderate Severe

Weight loss 3-5% 6-9% >10%

General Condition Alert, restless Thirsty, lethargic Cold, sweaty, limp

Pulse N. rate, vol Rapid, weak Rapid, feeble

Respiration Normal Deep, rapid Deep, rapid

Ant. Fontanelle Normal Sunken Very Sunken

Systolic pressure Normal Normal or low Low, unrecordable

Skin turgor Normal Decreases Markedly Eyes Normal Sunken, dry Grossly sunken

Mucus membrane Moist Dry Very dry

Urine output Adequate Less, dark Oliguria, anuria

Capillary refill Normal < 2 sec > 3 sec

Estimated deficit 30-50 mg/kg 60-90 ml/kg-1 100 ml/kg

History, Clinical and Evaluation Important

Confirmation by :

1. Serum osmolarity and serum sodium

2. Acid-base status, Serum pH, Base deficit

3. Serum Potassium compared with pH

4. Urine Output [To rule out ATN]

Hyponatremic Dehydration : Serum Osmolarity

<270 m.Osmol-1

Serum Na+ <130mEq/L

Fluid Management ….….

Isonatremic Dehydration : Serum Osmolarity

270-300 m.Osmol-1

Serum Na+ 130-150 mEq/L

Hypernatremic Dehydration : Serum Osmolarity

>310 m. Osmol-1

Serum Na+ >150 mEq/L

• Initiate treatment for deficit before investigation available

• Initiation with a bolus of NS over 10-12 min to improve

circulation and restore renal perfusion

Fluid Management ….….

• Patient with known contraction alkalosis : 50% dextrose with 0.9% NS (Reasonable fluid of choice)

• Patient with known met. acidosis : 250 ml of 0.9% NS + 28 ml of 7.5% Soda bicarbonate solution + 232 ml of 5% dextrose.

This gives approx. Dextrose 1.2%

Sodium 149 mEq

Chloride 115 mEq

Sod. Bicarbonate 25 mEq

Fluid Management ….….

• Lactate / Acetate containing solution aggravate met.

acidosis because of failure of formation of bicarbonate

from its precursors due to poor circulation status.

• Febrile response to volume contraction – Due to

decrease in skin blood flow Decrease heat

dissipation.

• Hyperosmolarity Increased threshold for sweating

Increase calorie and fluid requirement

Fluid Management ….….

Fluid deficit due to overnight fasting :• Advocated to prevent risk of pul. aspiration during

anaesthesia• Children : residual gastric vol., pH; Clear fluids

allowed upto 2 hours before surgery.[Sphinter W.M. 1990: Anaesth Intensive Care 18:522-526]

• Sips of fluid : peristalsis but no gastric secretion if protein absent.

• H2 blockers : gastric pH, gastric vol.

Sertherland AD et al. 87, Can J. Anaesth 34. 117-121.

Fluid Management ….….

Current recommendations :

Clear fluids : 2 hours

Milk : 4 hours

General Rule :

Preop. Fluid deficit = Maint./hr. x Hrs of fluid restriction

Before Surgery

50% in 1 hour 25% each in next 2 hours

Fluid Management ….….

Maintenance fluid requirements in neonates & infants: Daily and hourly

Age (d) / Wt (Kgs)

Requirements : ml/kg-1 day-1

Hourly : mlkg-1hr-1 Type of fluid

1 20-40 2-3 10% dextrose

2 40-60 3-4 10% dextrose in 0.22% saline

3 60-80 4-6 10% dextrose in 0.22% saline

4 80-100 6-8 5-10% dextrose in 0.22% saline

0-10 kgs 100 4 mlkg-1hr-1 5% dextrose in 0.45% saline

10-20 kgs 1000+50 mlkg-1 40 ml+2 mlkg-1hr-1 5% dextrose in 0.45% saline

> 20 kgs 1500+20 mlkg-1 60 ml+1 mlkg-1hr-1 5% dextrose in 0.45% saline

Composition of commonly used intravenous fluids

Electrolytes (meqL-1)

NS Ringers lactate

Isolyte P Plasmalyte A

D5 Albumin 5%

Hetastrach 6%

Na+ 154 130 26 140 - 145±15 154

K+ - 4 21 5 - <2.5 -

Cl 154 109 21 98 - 100 154

Mg++ - - 3 - - - -

Acetate - - 24 27 - - -

Lactate - 28 - - - - -

Glucose (gm%)

- - 5 - 5 - -

Phosphate (mg%)

- - 3 - - - -

Osmolarity (mOsmL-1)

308 274 - 295 252 330 310

• Meets ongoing fluid & electrolyte demands during surg.

• Does not include blood loss / third space loss into gut or interstitial space.

• Maintenance Fluid covers:

- Insensible loss [evaporative loss]

- Urinary loss

• Insensible loss Solute free loss of water through skin & lungs, usually 30-35% of total maint. req.

Maintenance Fluid Therapy

Determinants of Insensible loss : Ambient Temp. HumidityGest. Age Resp. patternExposed surface area

• Ventilation with humidified gases insensible loss.• In premature infants and patients with D. insipidus

Obligatory production of dil. urine Appropriate in maintenance fluid required.

• In excess ADH secretion Patients unable to urine osmolality to 300 mOsm need to vol. of maint. fluid

Maintenance Fluid Therapy

Gastroschisis

Surgical trauma Type of Surgery Fluid replacement

Minimal Inguinal hernia repair 1-2 mlkg-1hr-1

Moderate Ureteral implantation 4 mlkg-1hr-1

Severe Scoliosis, bowel obstruction > 6 mlkg-1hr-1

Intravenous fluid requirements in InfantsDay 1 of life 2 ml/kg per hourDay 2 of life 3 ml/kg per hourDay 3 of life 4 ml/kg per hourIntravenous fluid requirements in children<10 Kg 10 ml/kg per day10-20 Kg 1000 ml + (50 ml/kg per day for each kg over 10 kg)>20 Kg 1500 ml + (20 ml/kg per day for each kg over 20 kg)Wt. 10 12 14 16 18 20 30mL/h 40 45 50 55 60 65 70

Replacement of blood lossIn children, all blood loss should be replaced.

Done with packed RBCs/whole blood/Crystalloid/ Colloids

Davenport’s law :

<10% blood loss : No blood req.

10-20% Consider case by case

>20% Consider packed RBCs/Whole blood

Replacement : Crystalloid 3 ml for each ml of

blood loss

Ensure adequate oxygenation

Minimum hematocrit 30% older children

40% neonates acceptable

Sacrococcygeal Teratoma

• Responsibility of an anesthesiologist

• Sufficient fluid required to compensate for NBM hrs + insensible loss during op.

• Loss considerable during major abdominal / thoracic surgery

• In most cases 10 ml/kg/hr of Ringer lactate in D5 in water

• Blood loss : Weighing sponges

Suction bottle accumulation

• Actual loss more because of blood in drapes and op. field

Intraoperative Fluid Management

• In a child with normal Hb pre-op. : Whole blood / packed RBCs infusion if blood loss 10% of B.V.

• FFP/Albumin in extreme dissection without blood loss.

• Emergency : Trauma / G.I. Bleed Continue Pre-op. resuscitation with rapid transfusion during op.

• Prolonged hours of op.

Monitoring Urine Output

Serum Electrolyte & blood glucose

Hematocrit and blood gases.

Intraoperative Fluid Management ……..

Post Op-Period

- Optimum replacement and maintenance pre. and

intraop. child in fluid and electrolyte balance postop.

Immediate Post-Op.

- Drainage from chest tube/ intraperitoneal drains

measured & replaced with blood plasma

- GIT drainage collected Sample for electrolytes

Measured vol. replaced at intervals of 4-12 hours.

- Satisfactory oral intake : 3-5 days in most cases.

Review of Finer Points

1.1. Why fluid therapy needs special consideration in Why fluid therapy needs special consideration in children?children?

A. 1) Greater insensible loss

2) Greater urinary loss

3) Larger turn over

4) Inadequate expression of thirst

5) Easy fluid overload

6) Small total volume required

7) Diffusion volume and distribution of body water

Disturbance in Fluid Balance in adults

Extracellular vol. deficit : Common fluid disorder in

surgical patients.

Acute deficit associated with CVS & CNS signs.

Chronic deficit : in skin turgor and sunken eyes +

CVS & CNS signs.

Signs and Symptoms of Volume Disturbances

System Volume Deficit Volume Excess

Generalized Weight loss

Decreased skin turgor

Weight gain

Peripheral edema

Cardiac Tachycardia

Orthostasis/

hypotension

Increased cardiac output

Increased central venous pressure

Collapsed neck veins Distended neck veins Murmur

Renal Oliguria, Azotemia

Gastrointestinal Ileus Bowel edema

Pulmonary Pulmonary edema

Laboratory Exam :

Severe deficit BUN

Hemoconcentration

G.F.R.

Urine osmolality >

Serum osmolality

Urine Na < 20 mEq/L.

Na+ concentration does not reflect vol. deficit.

What are the common causes of vol. def. in What are the common causes of vol. def. in surgical patients?surgical patients?

1. Loss of GIT fluid : NG suction Peritonitis

Vomiting Obstruction

Diarrhoea

Fistula

2. Sequestration sec. to soft tissue injury

3. Burn

4. Prolonged surgery : Intra-abdominal procedureIntestinal Obstruction

Volume Control

Volume changes sensed by

Baroreceptor Osmoreceptors

Modulate Vol.

Sensors located in

Aortic arch and carotid

sinsuses

Detect changes in fluid

osmolality through

osmoreceptors changes

in thirst & diuresis

through kidney

Sodium• Normal values 135 – 145 mEq / L• Concentration Changes : Changes in Serum Na+ inversely

proportional to TBW

Electrolyte Abnormalities

Hyponatremia

(Excess of ECW)

Volume Status (ECV)

High

Normal

Low

Intake Hyperglycemia Sodium intake

Postop ADH secretion Plasma lipids/ proteins Gastrointestinal losses

Drugs SIADH Renal losses

Water intoxication Diuretics

Diuretics Primary renal disease

Low Serum Sodium level - Na+ depletion

- Dilution Intentional

Iatrogenic

To differentiate the Etiology : Systemic review of the

causes

- Exclude hyperosmolar causes (Hyperglycemia /

Mannitol)

- Consider depletional / dilutional causes

- Extrarenal (GIT) loss : Urine Na (<20 mEq/L)

- Renal loss : Urine Na (>20 mEq/L)

How will you treat Hyponatremia?How will you treat Hyponatremia?

Most cases treated by free water restriction

If severe : Restrict Na+

Symptomatic Hyponatremia (< 120 mEq/L)• If neurological s/s present : Give 3% NS Na+ level no more than 1 mEq/L/hour until Se. level

130 mEq/L or s/s improve.• Asym. Hyponatremia : Na+ level by no more than 0.5

mEq/L to a max. of 12 mEq/L/day. slower in chr. states• Rapid correction may cause PONTINE MYELINOLYSIS

with seizures, weakness / paresis, akiness and unresponsiveness permanent brain damage & death.

Hypernatremia (Loss of free water / gain of sodium)

Volume status

High

Normal

Low

Iatrogenic Na+ adm. Nonrenal water loss Nonrenal water loss

Mineralocorticoid excess

Aldosteronism

Cushing’s disease

Congenital adrenal hyperplasia

Skin Skin

Gastrointestinal Gastrointestinal

Renal water loss Renal water loss

Renal disease Renal disease

Diuretics Osmotic diuretics

Diabetes insipidus Diabetes insipidus

Adrenal failure

Hypernatremia - Loss of free water

>145 mEq/L Gain of Na+ in excess of water

How will you treat Hypernatremia?How will you treat Hypernatremia?

Hypernatremia : Treat associated water deficit

Hypovolemia : Treat with normal saline, followed by Hypotonic fluid (D5 or D5 in ¼ NS) after restoration of adequate volume status.

Water deficit (L)=

Serum Na – 140X

TBW140

in Se. Na+ no more than 1 mEq/h and 12 mEq/d.Chr. hypernatremia : Sodium correction (0.7 mEq/L/H)Overly rapid correction : Cerebral edema & herniationFreq. neurological and Se. Na+ assessment required.

Potassium AbnormalitiesAv. Dietary intake : 50-100 mEq/d

Flux of K+ influenced by – Surgical stress

Injury

Acidosis

Tissue Collection

Extracellular K+ maintained by renal excretion (10-700 mEq/d)

2% of total K+ : extracellular : Critical to cardiac and neuromuscular function.

Hyperkalemia Serum K+ level above 5.0 mEq/L. (N) range : 3.5 – 5.0 mEq/L.

HyperkalemiaIncreased intake

Potassium supplementationBlood transfusionsEndogenous load/destruction : hemolysis, rhabomyolysis, crush injury, gastrointestinal hemorrhage

Increased release of K+ from cells.AcidosisRapid rise of extracellular osmolality (hyperglycemia or

mannitol)Impaired excretion by kidney

Potassium-sparing diuretics, ACE inhibitors, NSAIDSRenal insufficiency / failure

What are the signs & symptoms of hyperkalemia?What are the signs & symptoms of hyperkalemia?

GIT Nausea, Vomiting, DiarrheaNeuro-muscular Weakness

Ascending paralysisResp. failure

CVS : Cardiac arrhythmiaECG : Peaked T wave (Early)

Flattened P wave Prolonged PR interval Widened QRS Sine wave formation VF

How will you treat hyperkalemia?How will you treat hyperkalemia?

Potassium removal• Kayexalate (cation exchange resin)

– Oral administration is 15-30 g in 50-100 mL of 20% sorbitol

– Rectal administration is 50 g in 200 mL 20% sorbitol

Shift potassium

• Glucose 1 ampule of D50 and regular insulin 5-10 units I.V.

• Bicarbonate 1 ampule I.V.• Nebulized Albuterol (10-20 mg)

Goal : To decrease body K+ and shift K+ from extracellular to intracellular.

• Discontinue exogenous K+ intake (IV, enteral and parenteral solution)

• Circulatory overload / Hypernatremia may result from Kayexalate and bicarbonate.

• Ca. Gluconate (5-10 ml of 10%) / Ca Chloride to counteract myocardial eff. of Hyperkalemia.

• May cause digitalis toxicity in patients on digitalis. • Dialysis When conservative measures fail.

How would you treat hyperkalemia? .......How would you treat hyperkalemia? .......

Hypokalemia

– Common in surgical patients

– K+ by 0.3 mEq/L for every 0.1 in pH above normal.

– Mg depletion due to drugs like amphotercin,

Aminoglycosides, Toscarnet, Cisplatin Renal K+

wastage.

HypokalemiaInadequate intake

Dietary, potassium-free intravenous fluids, potassium-deficient total parenteral nutrition

Excessive potassium excretion

Hyperaldosteronism

Medications Penicillins, diuretics

Gastrointestinal losses

Direct loss of potassium from gastrointestinal fluid (diarrhea)

Renal loss of potassium (gastric fluid, either as vomiting or high nasogastric output)

What are signs & symptoms of hypokalemia?What are signs & symptoms of hypokalemia?

GIT - ileus, Constipation.

Neuromuscular : Weakness, fatigue, tendon reflexes paralysis

Cardiovascular : Cardiac arrest

Pulseless electric activity

asystole

ECG Changes : U Waves

T wave frequency

ST seg. changes

Arrhythmia (Patient on digitalis)

Serum potassium level <4.0 mEq/L

• Asymptomatic, tolerating enteral nutrition: KCl 40 mEq

per enteral access x 1 dose

• Asymptomatic, not tolerating enteral nutrition: KCl 20

mEq IV q2h x 2 doses

• Symptomatic: KCl 20 mEq IV q1h x 4 doses

• Recheck K+ level 2 hrs after end of infusion; if <3.5

mEq/L & asymptomatic; replace as per above protocol

How will you treat hypokalemia?How will you treat hypokalemia?

Potassium repletion : Determined by symptoms

Oral Supplementation : Mild / asymptomatic.

IV : Not more than 10-20 mEq/h in unmonitored setting.

40 mEq/hr if ECG monitoring available.

If sec. to Mg depletion : Correct Mg def. first

Exercise caution in patient without oliguria / impaired

renal function.

Magnesium Magnesium

• 4th most common mineral in body

Primarily intracellular

• 1/3 of extracellular Mg bound to serum albumin

• Plasma levels poor indicator in presence of

Hypoalbuminemia

• Normal dietary intake - 20 mEq (240 mg) / day

Excretion : Feces & Urine.

Hypermagnesemia : RareImpaired renal function

Excess intake Mg containing laxative /

AntacidsWhat are the signs & symptoms of Hypermagnesemia?What are the signs & symptoms of Hypermagnesemia?GIT : Nausea & VomitingNeuromuscular : Weakness, lethargy, decreased

reflexes.CVS : Hypotension & arrest.ECG : Increased PR interval

Widened QRSElevated T waves.

Treatment

How will you treat Hypermagnesemia?How will you treat Hypermagnesemia?

– Withhold exogenous sources of Mg

– Correct volume deficit

– Correct acidosis

– Acute symptoms : Inj. Ca chloride 5-10 ml

– Dialysis in severe cases.

Hypomagnesaemia

Diminished absorption or intakeMalabsorption, chronic diarrhea, laxative abuseProlonged gastrointestinal suctionSmall bowel bypassMalnutritionAlcoholism

Increased renal lossDiuretic therapy (loop diuretics, thiazide diuretics)Hyperraldosteronism, Bartter’s syndromeHyperparathyroidism, hyperthyroidismHypercalcemiaDrugs (aminoglycoside, cisplatin, amphotericin B Pentamidine)

OthersDiabetes mellitusPost parathyroidectomy (hungry bone syndrome)Respiratory alkalosisPregnancy

Causes

Treatment : Hypomagnesemia

How will you treat Hypomagnesemia?How will you treat Hypomagnesemia?

• Asymptomatic / Mild : Oral supplementation

• Intravenous correction depends upon severity

Magnesium level 1.0-1.8 mEq/L :

• Magnesium sulfate 0.5 mEq/kg in normal saline 250

mL infused IV over 24 h x 3 days

• Recheck magnesium level in 3 days

Magnesium level < 1.0 mEq/L:

• Magnesium sulfate 1 mEq/kg in normal saline 250 mL

infused IV over 24 h x 1 day, then 0.5 mEq/kg in

normal saline 250 mL infused IV over 24 h x 2 days

• Recheck magnesium level in 3 days

If patient has gastric access and needs a bowel regimen:

• Milk of magnesia 15 mL (approximately 49 mEq

magnesium) q24h per gastric tube; hold for diarrhea

CalciumVast majority in bony matrixExtracellular fluid <1%Se. Ca2+ : 3 forms Protein bound 40%

Complexed to anions (PO4) : 10%Ionized : 50%

Ionized fraction responsible for neuromuscular stability Albumin measurement necessary when measuring total

Ca2+ Adjust total Serum Ca2+ down by 0.8 mg/dLfor every 1-g/dl in albumin.Acidosis Protein binding : ionized fraction

Hypercalcemia

Defined as Serum Ca > 8.5 – 10.5 mEq.

or

in ionized as Ca level > 4.2 - 4.8 mg/dl

Increased intake or absorptionMilk-alkali syndromeVitamin D or vitamin A excessEndrocrine disordersPrimary hyperparathyroidism (adenoma, hyperplasia, carcinoma)Secondary hyperparathyroidism (renal insufficiency, malabsorption)AcromegalyAdrenal insufficiencyNeoplastic diseasesMiscellaneous causesThiazide diuretic-inducedPaget’s disease of boneHypophosphatasiaImmobilizationFamilial hypocalciuric hypercalcemiaComplications of renal transplantationIatrogenic

Causes of hypercalcemia

What are the signs and symptoms of hypercalcemia?What are the signs and symptoms of hypercalcemia?

GIT : Anorexia, Nausea/vomiting, abd. pain

Neuromuscular : Weakness, Confusion, Coma, Bonepain

Renal : Polydipsia

CVS : Hypertension, arrhythmia, Polyuria

ECG : Short QT interval

Prolonged PR & QRS interval

QRS Voltage

T Wave flattening & widening

AV Block CHB Cardiac arrest

How will you treat Hypercalcemia?How will you treat Hypercalcemia?

Symptomatic hypercalcemia (>12g/dl) requires t/t

Treatment of hypercalcemia without malignancy

• Start with saline volume expansion This renal

resorption of Ca.

• Add loop diuretic after achieving adequate volume

status. But these are temporary measures.

Drugs :

– Biphosphonates

– Calcitonin

– Corticosteroids

– Gallium Nitrate, Mithramycin

Refractory Hypercalcemia : Dialysis

Hypocalcemia

Decreased intake or absorptionMalabsorptionSmall bowel bypass, short bowelVitamin D deficit

Increased lossAlcoholismChronic renal insufficiency Diuretic therapy

Endocrine diseaseHypoparathyroidism (genetic, acquired; including hypo- and hypermagnesemia)SepsisPseudohypoparathyroidsimCalcitonin secretion with medullary carcinoma of the thyroidFamilial hypocalcemia

Serum Ca2+ <8.5 – 10.5 mEq/L, in ionized Ca2+ < 4.2-4.8 mg/dL

What are the signs and symptoms of hypocalcemia?What are the signs and symptoms of hypocalcemia?

Neuromuscular : Hyperactive reflexes, Parasthesia

Carpopedal spasm, seizures

Chvostek sign

Trosseau sign

CVS : Heart failure, cardiac contractility

ECG : Prolonged QT interval

T wave inversion

Heart block

V.F.

Hypocalcemia

How will you treat hypocalcemia?How will you treat hypocalcemia?Normalized calcium <4.0 mg/dL• With gastric access and tolerating enteral nutrition :

Calcium carbonate suspension 1250 mg/5 mL q6h per gastric access; recheck ionized calcium level in 3 days

• Without gastric access or not tolerating enteral nutrition: Calcium gluconate 2 g IV over 1 h x 1 dose; recheck ionized calcium level in 3 days.

Acute Hypocalcemia : Inj. Cal. gluconate 10% iv• Correct asso. deficit in Mg, K+, pH• Hypocalcemia refractory if Hypermagnesemia is not

treated first

Phosphorus

– Primary intra-cellular divalent anion

– Abundant in metabolically active cells

– Responsible for maintaining energy production

(ATP)

– Levels controlled by renal excretion

Hyperphosphatemia

Massive load of phosphate into the extracellular fluid From outside the body Hypervitaminosis DLaxatives or enemas containing phosphateIntravenous phosphate (especially if renal insufficiency coexists)Cell destruction by chemotherapy of malig, particularly lymphoproliferative diseaseMetabolic acidosis (lactic acidosis, ketoacidosis) Respiratory acidosis (phosphate incorporation into cells is disturbed)Decreased excretion into urineRenal failure (acute, chronic)HypoparathyroidismPseudohypoparathyroidism Excessive growth hormone (acromegaly)PseudoperphosphatemiaMultiple myeloma, hypertriglyceridemia, cell lysis

Causes

What are the signs and symptoms of What are the signs and symptoms of

Hyperphosphatemia?Hyperphosphatemia?

• Mostly asymptomatic

• In advanced casesmetastatic soft tissue deposits

How will you treat Hyperphosphatemia?How will you treat Hyperphosphatemia?

Phosphate binders: Sucralfate

Aluminum containing antacid

Dialysis for patient with renal failure

Hypophosphatemia

Diminished supply or absorptionStarvationParenteral alimentation with inadequate phosphate contentMalabsorption syndrome, small bowel bypassVitamin D-deficient and vitamin D-resistant osteomalaciaIncreased lossPhosphaturic drugs : theophylline, diuretics, bronchodilators, corticosteroidsHyperparathyroidsim (primary or secondary)HyperthyroidismRenal tubular defects Inadequately controlled diabetes mellitusIntracellular shift of phosphorus Respiratory alkalosis, Salicylate poisoningElectrolyte abnormalities Hypercalcemia, HypomagnesemiaMetabolic alkalosis

Causes

What are the signs and symptoms of What are the signs and symptoms of

Hypophophatemia?Hypophophatemia?

• Usually not significant unless severe deficiency

• Related to O2 del. to tissue and in ATP

• Manifest as cardiac dysfunction / Muscle

weakness

How will you treat Hypophosphatemia?How will you treat Hypophosphatemia?

Phosphate level 1.0 – 2.5 mg/dL

• KPHO4 or NaPO4 0.15 mmol/kg IV over 6 h x 1 dose

• Recheck phosphate level in 3 days

Phosphate level < 1.0 mg/dL

• Tolerating enternal nutrition : KPHO4 or NaPO4 0.25 mmol/kg over x 1 dose

• Recheck phosphate level 4 hours after end of infusion• KPHO4 or NaPO4 0.25 mmol/kg (LBW) over 6 h x 1

dose; recheck phosphate level 4 hours after end of infusion; if <2.5 mg/dL, then KPHO4 or NaPO4 0.15 mmol/kg (LBW) IV over 6 h x 1 dose

How to calculate the rate of fluid infusion?How to calculate the rate of fluid infusion?

For routine IV set :

15 drops = 1 ml

‘Rule of TEN’ for fluid Cal. for 24 hours

IV fluid in litre / 24 hours x 10 = Drop rate / min

‘Rule of Four’ for fluid Cal for one hour

Drop rate / min. x 4 = Vol. in ml/ hour

For micro-drip IV set

1 ml = 60 drops

No. of drops / min = Vol. in ml / hr.

Preoperative Fluid Therapy

A frequently used formula for maintenance fluid for first 10 Kg : 100 ml / kg / dfor next 10-20 Kg : Additional 50 ml/kg/dfor wt. > 20 kg : 20 ml / kg / dayBut many surgical patients have vol. / electrolyte disturbance

associated with their disease.Therefore, pre-op. volume status and electrolyte assess a must.Vol. deficits in patients with Emesis / Diarrhea

Poor intakeIII space lossGI dysfunctionPeritoneal / bowel

inflammationAscitis, crush injuries

• Tachycardia & Orthostasis predominate with

acute vol. loss accompanied with oliguria &

hemoconcentration

• Ac. volume deficits should be corrected prior to

surgery.

• Start fluid replacement with isotonic crystalloid

depending upon electrolyte profile.

Patient with CV signs of volume deficit

1-2 L of isotonic fluid followed by continuous infusion

Resuscitation guide : - Reversal of signs of volume deficit

(Vital signs)

- Adequate urine output (½ – 1 ml / kg / hour in adult)

- Correction of base deficit

Close monitoring essential in all esp. so in patients with

impaired renal function

Electrolyte abnormality – correct to the extent that ac.

S/S relieved prior to surgery.

Intraoperative Fluid Therapy

• Compensatory mechanism lost with induction of anaesthesia.

• Hypotension will manifest if volume deficit present.

• Measure blood loss, III space loss, loss from exposed bowel, large soft tissue wounds, complex fractures and burns and replace accordingly.

In general which fluid is appropriate intraoperatively?In general which fluid is appropriate intraoperatively?• Selection of fluid needs to be individualized depending

upon age, vitals, basic etio. and type of surgery and asso. Illness.

RL: To replace I.O. fluid loss

Most physiological fluid, also corrects acidosis

NS: Used intraop when RL contraind. or when large vol. of resuscitation required like hypovol. shock

D5: Initial fluid replacement

- Replacement for insensible fluid loss

- Maintenance fluid deficit during starvation

- Corrects intracellular dehy. & provides calories

Postoperative Fluid Therapy

• Should be based on patient’s current estimated volume status and projected ongoing losses.

• Any pre. / intraop. deficit should be corrected and ongoing req. included in maintenance.

• III sp. losses should be included.

• In early post op. period : Isotonic solution

• Guide : Vital Signs and Urine output

• If uncertainty : CVP / Swan-Ganz Catheter

• After 24-28 hours : Change to 0.45% Saline without added dextrose in patient unable to tolerate enteral nutrition.

• Add potassium if renal function and urine output adequate.

• Daily fluid requirement based on volume electrolyte status.

• No need for electrolyte measurement in uncomplicated cases

What are special considerations in postoperative What are special considerations in postoperative fluid therapy?fluid therapy?

Overestimation of losses may lead to volume

excess

Earliest sign : Weight gain

Av. Post op. patient not requiring nut. support

loses ¼ to ½ pound /day.

What problems can occur if following iv fluids are used as What problems can occur if following iv fluids are used as sole agents for maintenance?sole agents for maintenance?

A. 1) D5: Provides only water & glucose. No electrolytes.

Risk of Hyponatremia / Hypokalemia

2) DNS : Contains Na 154 mEq/L,

No Potassium, [(N) child requires 30-50 mEq]

Risk of hypernatremia, hypokalemia

3) RL : Na 130 mEq, Pot. 4 mEq, No glucose

Risk of Hypernatrania, Hypokalemia, Hypoglycaemia

Can we use D5 in initial phase of shock?Can we use D5 in initial phase of shock?

No, because

1. 1 litre D5 in intravascular

volume by 83 ml

1. Contains no electrolytes electrolytes

disturbance

2. Rapid infusion Osm. diuresis Detrimental

Omphalocele

Management in Neuro-surgical patients

– Special challenge to anesthesiologists

– Often receive diuretics (Mannitol/ Frusemide) to treat cerebral edema

large amounts of IV fluids to correct pre-op dehydration and to maintain intra/post op. hemodynamic stability

– Fluid restriction if excessive Hypotension ICP CPP devastating

– Little human data on the impact of fluid on brain

– IV fluid therapy manipulates

1. Osmolality

2. Colloid oncotic pressure

3. Hematocrit 30-33% optimal viscosity &

O2 carrying capacity may improve neurological

outcome.

Hct <30% neurological injury

How will you control ICP and brain swelling?How will you control ICP and brain swelling?

1. Diuretics : Mannitol & Frusemide used extensively

Mannitol : Creates an osmotic gradient between intravas. comp and brain parenchyma

Frusemide : Reduces cell swelling

Also CSF production

2. Hypertonic salt solutions : primarily used for small vol. resuscitation in patient with hemo. Shock

Data suggest that they ICP and improve CPP similar to Mannitol.

Disadvantages : Danger of Hypernatremia

Rebound ICP

3. Hypertonic / Hyperoncotic solution –

(E.g. Hypertonic Hetastarch or Dextrose solution)

– Have powerful hemodynamic properties

– Advantageous in patients with head injury and multiple trauma for prevention of secondary ischemic brain damage

– Small volume can restore normovolemia rapidly

– Successfully used to treat ICT in patients with head injury and stroke

Implications for Patient Care

Fluid Restriction : Moderate fluid restriction causes in serum osmolality and prevents hypo-osmotically driven edema beneficial

Intra Op. Replacement :

– Rate should be sufficient to replace urinary output and insensible losses

– Repeat osmolality check required

– Small volume of RL safe

If large vol. required : use a more isotonic fluid or a combination of isotonic crystalloid and colloid

Post op. Period - Large volume not required

Periodic osmolality check and give fluids accordingly

What are the points to be remembered for a head injury What are the points to be remembered for a head injury patient?patient?

– Prompt restoration of systemic pressure is essential– Avoid Hypotonic solution (RL), – Avoid glucose containing solution– Give fluids with osmolality around 300 mOsm/L– Colloids for large volume deficit

Subarachanoid Hemorrhage (SAH)

Avoid Hypovolemia and Hyponatremia

– Isotonic crystalloids usually take care of

hyponatremia

– If severe hyponatremia : use mild hypertonic fluids

(1.25% or 1.5% saline)

– Avoid fluid restriction

– Hypertensive / Hypervolemic therapy widely

accepted to prevent cerebral vasospasm

Management of patients with renal diseases

What are the General Rules?What are the General Rules?

1. Fluid restriction : required in edematous and oliguric

patients to avoid volume overload, pulmonary

congestion, hypertension / hyponatremia

Anuric patient : Fluid restricted upto 500 ml/day only

Oliguric patient : Fluid intake = Urine Output + 500 ml

Monitor urine output chart and daily weight.

Loss of weight in accumulated fluid edema

2. Do not chase urine output in edematous patient

– Urine output in response to diuretic therapy

– Aim is removal of accumulated fluid, therefore

continue fluid restriction.

3. Salt restriction : req. to edema, pulmonary

congestion and hypertension.

4. Avoid Hyperkalemia : Can be fatal

Avoid K+ rich food

Avoid K+ rich IV fluids

Acute renal failure : Characterized by rapid decline in renal function.

Accumulation of water, crystalloid solutes and nitrogenous end products.

Has varied presentation :

Pre-renal azotemia

Non-oliguric ac. renal failure

Oliguric renal failure

Diuretic phase of ac. renal failure

Pre-renal Azotemia :

• Pt. improve with early & adequate fluid therapy

• 0.5 – 1 Lt. isotonic saline infused over 30-60 min. if

no response IV diuretics to promote urine flow

• Monitor : Pulse, BP and JVP

• Give isotonic saline in hypotensive states.

• With-hold K+ till urine output is established.

Non-oliguric ARF :

• Due to Septicemia, drug toxicity, A.I.N.

• Diagnosis difficult as there is no urine output.

• High index of suspicion req.

• Do not need fluid or salt restriction

• Restrict Potassium intake.

Oliguric ARF: If urine output <40 ml/d in adults or <0.5 ml/kg/hr in children

excretion of water, electrolytes, nitrogenous waste products

• Restrict Salt and water (esp. K+)

• Maintain daily wt loss chart. (Daily loss of 0.2 to 0.3 kg ideal)

- Treat with diuretics to establish urine outflow.

- If ineffective - Mannitol/ low dose dopamine (<3 µg/kg/min)

Diuretic phase of ARF :

• Renal functions recover through repair of renal

tissue.

- Do not chase urine output at this stage

- Avoid volume depletion and dehydration

- Replace deficit of NaCl, HCO3, K+, Mg etc.

- Preferred IV fluid 0.45% saline with K+ as

required

Chronic Renal FailureCRF due to chr. glom. disease :

S/S of volume overload and hypertension

restrict fluid and salt intake

– Diuretics

– Avoid Hyperkalemia

– Preferred IV fluid D-5 or D-10

CRF due to chronic tubulo-interstitial disease :

- Absence of edema / Volume dep. due to polyuria

– Advise plenty of fluid and salt intake to prevent dehydration

– Correct Met. acidosis Give Sodium Bicarbonate

– Avoid & treat hyperkalemia

How will you manage TURP syndrome?How will you manage TURP syndrome?

S/S secondary to neuro., CVS and electrolyte

imbalance due to absorption of irrigation fluid

through prostatic veins.

Risk factors - Surgery > 60 min

- Prostate (Resected wt >30 gms)

- Irrigant volume > 30 L

- Inexperience

Prevention : Early diag. and prompt treatment

• Correct pre-existing Hyponatremia (risk factor)

• Irrigation fluid flow < 300 ml / min

• Avoid 5% Dextrose pre-op. pre-op. maintenance fluid.

• Prophylactic use of Frusemide

Treatment :

• Terminate surgery

• Diuretics : 66% cases corrected

• Fluid restriction

• Mannitol 15%

• Hypertonic saline : Slow I.V. 3% hypertonic saline.

In general 200 ml sufficient

Patient with Trauma

Tissue injury activated sys. infl.

response permeability of vas. endo

Tissue edema

Plasma shifts to interstitial extra-

cellular sp. intravascular volume

Concurrent hemorrhagic insult further reduction in

plasma volume

How will you resuscitate patients with trauma?

Fluid Resuscitation

Improves outcome : morbidity

Restores physiological homeostasis

Balanced salt solution infusion : current standard

Give as rapid as possible 1-2 L in adults

20 ml / kg in children

No reported difference in outcome with crystalloid v/s

colloid resuscitation

Options :

Isotonic crystalloids : Readily available, least expensive but larger infusion volume

required

Oncotic pr interstitial edema detrimental to lung

Hypertonic crystalloids :

Restore blood volume by maintaining a contracted interstitial space

Small volume required

Believed to have positive inotropic effect on myocardium & in renal, mesenteric & coronary blood flow

Colloids

- Favored by some

- More rapid and effective correction of

intravascular volume deficits

- Natural Colloids Carry the risk of transmission

of infection (HCV, HIV etc.)

- Anaphylactoid reaction

Combined Crystalloid – Colloid Resuscitation

Currently under investigation

Hypertonic component draws water out of intra-cellular space replenishes extra-cellular space.

Colloid component transiently partitions this fluid in plasma space prolongs beneficial hemodynamic effects

Studies indicate improved survival when hypertonic saline and Dextran40 (HSD) are used together.

HSD infusion : Corrects meta. derangement

improves arterial O2 tension

mesenteric & renal micro-circulation

Conclusion- Accurate fluid, electrolyte assessment & therapy

essential

- Precise calculation of preop. deficits, maintenance & ongoing loss req. a must for proper management of fluid homeostasis

- Practical wisdom indicates it is dose rather than the type of fluid that is important

- Judicious fluid management & a keen eye on pt’s status go a long way in benefiting the pt.

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