Fluid And Electrolyte Fluid And Electrolyte ManagementManagement

PresenterDr.Mithun.R

ModeratorDr.Rajeev Sharma

Body Water Body Water Compartments Compartments

• Intracellular water: 2/3 (40%)of TBW

• Extracellular water: 1/3 (20%)of TBW

- Extravascular water[interstitial]: 3/4

(15%)of extracellular water

- Intravascular water[plasma]: 1/4 (5%)of

extracellular water

Electrolyte contents Electrolyte contents (Commonly used IV (Commonly used IV fluids)fluids)

Solution Electrolyte contents (mEq /l) * g/L

Osmolarity(mOsmol.L-1)

Na+ Cl _ K+ Ca 2+ Glucose*

Lactate

Dextrose 5% (D5W)

50 Hypotonic 253

½ NS 77 77 Hypotonic 154

Lactated Ringer

130 109 4 3 28 !! Isotonic 273

N saline 154 154 Isotonic 308

D5 ¼ NS 38.5

38.5 50 !! Isotonic 335

D5 ½ NS 77 77 50 !! Hypertonic

432

3% Saline 513 513 Hypertonic 1026

CrystalloidsCrystalloids

Combination of water and electrolytesBalanced salt solution: electrolyte composition and

osmolality similar to plasma; example: lactated Ringer’s, Plasmlyte, Normosol.

- Hypotonic salt solution: electrolyte composition lower than that of plasma; example: D5W.

True solution, No particulate

Expands IVC adequately (less than colloids), however Small increase in plasma volume

Replenishes interstitial compartment

It leaves IVC faster ( t/2 20-30 minutes)

Cheap

Increase GFR

No risk of allergic reaction

Suspension of particle rather than a solution

High Molecular Weight: Unable to pass through semi permeable membrane

Remains confined to intra-vascular compartment (at least initially)

Do not correct water and electrolyte deficiencies

Examples: hetastarch (Hespan), albumin, dextran

ColloidsColloids

Antigenicity & Anaphylactic Reaction

Blood typing

Coagulopathy

Never exceed 1 – 1.5 liter/day (20 ml/kg/day)

ColloidsColloids

colloids

ColloidsColloids

Most logical choice for intravascular expansion

Since greater portion remains in IVC & for longer time ( t/2 3-6

hours)

Less volume is required& initial resuscitation is rapid

500 ml of colloids expands plasma by 500ml

Blood-derived: Albumin 5%( Heated, Antigenic)

Dextran: Dextran 70, Dextran 40

Gelfusine (Anaphylaxis)

Hydroxy ethyl ether Hetastarch 6%

MW = 450 000Effective Plasma

Expander

Least Antigenicity &Effect on

Coagulation

Colloids (Types)Colloids (Types)

colloidcolloid Advantages : Smaller

infused volume. Prolonged increase in plasma volume. Less cerebral edema.

Disadvantages :Greater cost Coagulopathy(dextran>HES). Pulmonary edema (capillary leak states). Decreased GFR. Osmotic diuresis (low molecular weight dextran)

crystalloidcrystalloid Advantages : Lower cost.

Greater urinary flow. Replaces interstitial fluid.

Disadvantages :Transient hemodynamic improvement. Peripheral edema(protein dilution). Pulmonary edema (protein dilution plus high PAOP)

Practical Fluid Practical Fluid BalanceBalance

H2O H

2O H

2O

Rule 1

Water without Na expands the TBW (enter both ICF & ECF in proportion to their initial volume)

ECFICF

Practical Fluid Practical Fluid BalanceBalance

Na+

Na+

Na+

Na+

Na+

Na+

Rule 2

All infused Na+ can not gain access to the ICF Because of the Sodium Pump

ECFICF

Isotonic = NO Water ExchangeIsotonic = NO Water Exchange

Hypotonic = Water Exchange Hypotonic = Water Exchange

a. Hypotonic saline (¼ NS)

H2O

Rule 3

Change in tonicity of Na solutions (relative to Plasma) causes water exchange

Practical Fluid Practical Fluid BalanceBalance

Hypertonic = water exchange Hypertonic = water exchange

b. Hypertonic solution

H2O

Simple guide line for Simple guide line for replacementreplacement

Prolonged vomiting and nasogastric suction : fluid of choice

normal saline. If urine out put is adequate, potassium is added to

it after 2nd day. Isolyte G can be given in an amount same as

upper GI loss, provided urine output renal status is normal.

Fluid loss due to small bowel fistulas causing diarrhorea : RL is

ideal may need additional bicarbonate and potassium

supplementation to treat metabolic acidosis and hypokalemia.

Loss of blood : if volume is less replacement is done with three

times volume of isotonic saline or RL. But if loss is greater , it

needs blood or colloids for replacement.

Orthostatic HypotensionOrthostatic Hypotension

• Systolic blood pressure decrease of greater than 20mmHg

from supine to standing

• Indicates fluid deficit of 6-8% body weight

- Heart rate should increase as a compensatory measure

- If no increase in heart rate, may indicate autonomic

dysfunction or antihypertensive drug therapy

Perioperative Fluid Perioperative Fluid TherapyTherapy

Pre-existing deficitsPre-existing deficits

Normal maintenance Normal maintenance requirementsrequirements

Abnormal lossesAbnormal losses

Pre-existing losses Pre-existing losses

Fasting (maintenance x no. of HR) Bowel preparation ---1L fluid loss Measurable fluid losses—NG suctioning,vomiting,ostomy

output Preoperative Bleeding, fistulae Diarrhea Diuresis – ketosis Occult losses

inflammatory traumatic edema Sequestration in third comp.

Increased insensible losses (0.5 ml/kg/hr) Fever (add 12% for 1oC) Hyperventilation Sweating

Normal Maintenance Normal Maintenance requirementsrequirements

Hypothetical 2000 ml/ day

Volume of 30 – 35 ml.kg-1day-1

Solutions: D5 or D5 ½ NS

1.5 -2 ml/kg/h

Weight Rate

10 kg 4ml/kg/h

10 – 20 kg

+2ml/kg/h

> 20kg +1ml/kg/h

Surgical Fluid Surgical Fluid LossesLosses

Blood lossBlood loss

Obligatory losses of fluidsObligatory losses of fluids

Redistribution – third Redistribution – third spacespace

EvaporationEvaporation

Blood LossBlood Loss

• Replace 3 cc of crystalloid solution per cc of blood loss

(crystalloid solutions leave the intravascular space)

• When using blood products or colloids replace blood loss

volume per volume

Third Space LossesThird Space Losses

• Isotonic transfer of ECF from functional body fluid

compartments to non-functional compartments.

• Depends on location and duration of surgical procedure,

amount of tissue trauma, ambient temperature, room

ventilation.

Replacing Third Space Replacing Third Space LossesLosses

• Superficial surgical trauma: 1-2 ml/kg/hr

• Minimal Surgical Trauma: 3-4 ml/kg/hr

- head and neck, hernia, knee surgery

• Moderate Surgical Trauma: 5-6 ml/kg/hr

- hysterectomy, chest surgery

• Severe surgical trauma: 8-10 ml/kg/hr (or more)

- AAA repair, nehprectomy

Monitoring fluid therapyMonitoring fluid therapy

1.skin and tongue: warm extremities and

normal elasticity of skin.

2.sensorium:improvement of anxiety and restlessness.

3.urine output: U.O. >30-50ml/hr in adults or >.5 to 1.0 ml/kg/hr in

children in absence of glycosuria or osmotic diuresis. Increased urine output

with decreasing urine specific gravity and omolality are other dependable

parameters 4.pulse rate:

correction of tachycardia to pulse rate <110/min. change from low volume

collapsing pulse to bounding pulse 5.blood

pressure 6.decreasing

hematocrit 7.blood urea

and serum creatinine: both will become normal. 8.

increase in urinary Na excretion >25 mEq/L

9. improvement of metabolic acidosis with improved peripheral perfusion

Post –operative fluid therapyPost –operative fluid therapy Depends upon clinical judgement of the patient’s status Goal of fluid therapy: to maintain blood pressure (>100/70 mm

of Hg), pulse rate <120/min and hourly urine flow between 30-50 ml along with normal temperature, warm skin, normal respiration and sensorium.

Depends upon type minor, major and nature of surgery short operative procedure and donot require handling

of intestine or viscera with little morbity will require only maintenance I.V. fluid to correct for the NPO state. After 4-5 hrs oral fluids is restarted and I.V. fluid is not needed i.e. hernia, minor orthopedic operations on limbs, minor plastic surgery

Patients with major surgeries where intestinal viscera need rest requires postoperative I.V. fluids for a few days. After ensuring normal movement of intestine, oral fluid intake is restarted.

Where handling of intestine is not required I.V. fluid is required for 24-48 hrs e.g. cardiac surgery,coronary bypass surgery, total hip replacement etc.

Routine postoperative orders Routine postoperative orders of I.V. fluid for first three of I.V. fluid for first three daysdays

First 24 hrs of surgery : 2 liters 5%-dextrose or 1.5 liters 5%-dextrose +500 ml isotonic saline.

Second post operative day: 2 liters of 5%-dextrose +1liter 0.9% saline.

Third post operative day: similar fluid +40-60 mEq potassium per day.

Maintenance fluids should be administered at a steady rate over an 18 to 24 hour period.

Infants respond to dehydration with decreased

blood pressure but without increased heart

rate.

Preoperative fluid deficit replaced with RL or ½

NS

Fluid therapy in special Fluid therapy in special surgical problemssurgical problems

Turp syndromeTurp syndrome: correction of severe and

symptomatic hyponatremia should be done with slow

administration of 3% hypertonic saline with I.V.

frusemide. Hyper tonic saline must be given very slowly

in divided doses with monitoring of serum sodium.

Rapid administration of saline leads to pulmonary

oedema and central pontine myelinolysis. In general

TURP syndrome can be corrected with 200ml of 3%

saline

TURP SYNDROME

Defined as serum Na+ <125mEq/L with two or more

clinical symptoms and signs.

Etiology - Intravascular absorption of irrigation fluid

absorption of free water dilution of serum sodium

Regional anaesthesia preferred over General

anaesthesia.

Fluid therapy in Fluid therapy in neurosurgeryneurosurgery Isotonic saline, 5% albumin and 6% hestarch are iso to

hyperosmotic,so they have minor effect on the brain’s water content or ICP. So these lfuids are safe to infuse.

Osmolality of RL is 274 mOsm/L and 5%-dextrose is 278 mOsmol/L. as both of them are hypotonic, they can increase ICP and cerebral oedema. So these fluid should be avoided or should be used judiciously.

5%- dextrose is hypotonic accelerates ICP and cerebral oedema.in acute ischemic brain damage produces more lactic acid free radicals which further damages the brain.

Guidelines of fluid Guidelines of fluid management of increased management of increased ICPICP

Acute phase: mannitol is main stay of therapy. Prolonged administration of mannitol should be avoided.

Maintenance therapy: fluid restriction and diuretics are the mainstay of maintenance therapy for ICP. The initial aim is to produce isovolumic hyperosmolality i.e. elevate serum osmolality without reducing the intravascular volume.The best fluid for this purpose is isotonic saline with added potassium chloride.

Fluid therapy in BurnsFluid therapy in Burns

Fluid resuscitation in first 24 hours Fluid therapy from 24 to 48 hours Fluid therapy after first 48 hours Indication of I.V. resuscitation are : 1. adults with >15-20% burns 2. child with 10% burns 3. electric burn with haemochromogens in the

urine 4. the extremes of age or elderly patients with

preexsisting cardiac or pulmonary disease

During initial period fluid resusitation sodium rich I.V. fluid in large quantity is required.

RL is the most preferred fluid for initial fluid

resuscitation Volume required=4×%BSA×body weight 24 hrs period

from the time of burn accident Out of total fluid requirement for 24hours half is given

first 8 hrs post burns and remaining half is given over the next 16 hrs

Electrolyte-free fluid i.e 5%-dextrose are avoided for initial fluid resuscitation

Colloid infusion is either ineffective or destructive in early period

BT is usually avoided initially

During the second post burns day the volume of fluid

infused per hour should be roughly reduced by 25-50%

Fluid infused – 5% dextrose but if sodium

supplementation is needed RL or .45% saline can be

added

The amount colloid infused after 24 hrs depends on

degree of burns volume roughly 0.3-0.5 ml/kg/% of burns.

Among colloids infusion albumin is often preferred

Fluid therapy after 48 hrsFluid therapy after 48 hrs

Is the sum of normal maintenance requirements

plus replacements of abnormal losses

Maintenance requirement contains water,

sodium 3mEq/kg and potassium 2mEq/kg

5% dextrose volume required is 1ml/kg/%

burns. Albumin with aim to maintain serum

albumin >2.5gm/dl.

SummarySummary

• Fluid therapy is critically important during the

perioperative period.

• The most important goal is to maintain hemodynamic

stability and protect vital organs from hypoperfusion

(heart, liver, brain, kidneys).

• All sources of fluid losses must be accounted for.

SODIUM (Na+)

Major cation of ECF ; Normal – 135-145mEq/L

Determines ECF & ICF Osmolality

Serum osmolality = 2x Na+ + glucose/18 +

urea/2.8

Normal – 275-290mOsm/kg

Maintain ECF volume and thus Blood pressure

HYPONATREMIA (Na+< 135mEq/L+)

HypovolemicExtra renal loss(urine Na+ <15mEq/L )

•Vomiting• Diarrhoea •Peritonitis•Tube drainage•Fistula•obstruction•Burn wound edema•hemorrhage

Renal loss(urine Na+ >15mEq/L)

•Excessive diuretics

•Salt losing

nephropathy

•Diabetic ketoacidosis

•Cerebral salt wasting

syndrome

Hypervolemic Euvolemic

•CHF

•Nephrotic syndrome

•Cirrhosis

•TURP syndrome

•Renal Failure

( urine Na+ >20mEq/L)

•SIADH•Hypothyroidism•Glucocorticoid deficiency•Psychogenic polydypsia

•Pseudohyponatre

miaNormal osmolality

hyperlipidemia

hyperproteinaemiaHigh osmolality

Hyperglycemia Mannitol

CLINICAL FEATURESMild

135-130 mEq/L

Moderate130-125 mEq/L

Severe<125mEq/L

Anorexia Personality Changes

Drowsiness

Headache Muscle Cramp Diminished reflexes

Nausea Muscular weakness

Convulsions

Vomiting Confusion Coma

lethargy Ataxia Death

TREATMENT

HYPONATREMIA (correct underlying etiology)

HYPOVOLEMIA OEDEMATOUS EUVOLEMIA

Salt and water No salt Water restriction

supplementation Water restriction

Loop diuretics

TREATMENT Chronic asymptomatic hyponatremia (>48hrs):

Rate of correction - 0.5 to 1.0 mEq/L/hour.

MAX 8mEq/L per day.

Rapid correction Central pontine

demyelination

Dysarthria, dysphagia, flaccid paralysis or coma

Diagnosed by CT or MRI (more accurate)

ACUTE hyponatremia with severe neurological

symptoms

Rapid correction with hypertonic saline 1.5 – 2mEq/L /hr for first 3-4 hours

Other supportive therapy for neurological

symptoms

Correct until Symptoms subside

Safe plasma Na+ concentration : 120-125mEq/L

Na+ Requirement = (140- Na+ )x Body weight x 0.6

TREATMENT

HYPERNATREMIA (Na+>145mEq/L)

Etiology – Usually : water deficit

Excess water loss

Insensible loss

Dermal -: heat exposure, severe burns

Respiratory -: patients on mechanical

ventilators.

Renal loss

Diabetes insipidus

central (ADH deficiency): pituitary surgery, basal

skull fracture and severe head injury

Nephrogenic – drugs (lithium, demeclocycline,

amphoteracin B,) hypokalemia, hypercalcemia etc

Excessive diuretics

Uncontrolled diabetes mellitus

Gastrointestinal loss : osmotic diarrhoea

Water deficit due to impaired thirst

Primary hypodypsia, confused or

comatous condition

Sodium Retention

Excessive I.V. Hypertonic NaCl or

NaHCO3

CLINICAL FEATURES

Polyuria and thirst

Neurological symptoms: altered mental

status, weakness, neuromuscular

irritability, focal neurological deficit,

seizures & coma

Hypertonicity contracts ICF volume brain cell

volume subarachnoid or intra-cerebral hemorrhage

TREATMENT

Restoration of ECF volume:

Water deficit :

Plasma Na+ concentration – 140

140

Rate of correction : 0.5mEq/L/hr and not more than

12 mEq/l over 24 hours

X total body water

ANAESTHETIC IMPLICATION

Increases the MAC of inhaled

anaesthetic agents:

Enhanced sodium conductance during

depolarisation of excitatory membranes.

POTASSIUM Determines excitability of nerves and muscle

cells including the myocardium.

Most abundant intracellular cation: 98% intracellular.

Poor intake

Non renal loss

Renal loss Redistribution

•Anorexia

nervosa

•Starvation

•alcoholism

•Vomiting

• diarrhoea

•excessive

sweating,

•large

nasogastric

aspiration

•Diuretics

•osmotic diuresis

• salt wasting

nephropathy

• Mineralocorticoid

excess

(primary or secondary),

Cushing’s syndrome,

• Steroid therapy

•Magnesium deficiency

•Amphoteracin B

Metabolic

alkalosis,

insulin, β2

agonist,

Hypokalemic

periodic

paralysis,

Vitamin B12

therapy,

Li overdose

Hypokalemia (K+ < 3.5mEq/L)

Etiology

** Surgical stress reduces

serum K+ by 0.5 mEq/L

Clinical Features

Commonly : Fatigue, myalgia and muscular weakness of

lower extremity

Smooth Muscle : Constipation, ileus or urinary

retention

Progressive weakness, hyporeflexia,

hypoventilation( due to respiratory muscle involvement)

Polyuria due to nephrogenic diabetes insipidus

Increased ammoniagenesis : precipitates hepatic

encephalopathy in patients with hepatic failure

Arrythmia Early changes

Flattening or inversion of T waves

Prominent U waves

ST segment depression

Prolonged QT interval

Flattening of T waves

Flat T waves

U waves

SEVERE HYPOKALEMIA

Prolonged PR interval

Decreased voltage

Widening of QRS

Ventricular arrythmia :VPC, ventricular

tachycardia

TREATMENT

Prevention of K+ Depletion

Patients receiving Digitalis, long term

diuretics or large dose steroids

Beware in special conditions like

hepatic failure, previous myocardial infarction

or IHD, Diabetes Mellitus

Post operative patients should receive 40 -

50 mEq/day of potassium

TREATMENT When to Treat

3.5 to 4 mEq/L :

No potassium supplementation

Add potassium sparing diuretics or

decrease dose of diuretics

3 to 3.5 mEq/L :

Treat in high risk groups <3 mEq/L :

Needs definitive treatment

IV KCl Therapy Reserved for symptomatic and severe cases

Common Guidelines

Continuous ECG monitoring

Avoid till urine output is established

Don’t give > 10- 20 mEq/L/ hour (typically

0.5mEq/kg/hr)

( 10ml of 15% KCL – 20 mEq/L)

Don’t give > 40 mEq/L

Don’t give more than 240mEq/ day

TREATMENT

Treatment of acidosis with NaHCO3 may

aggravate or precipitate hypokalemia.

KCL infusion : In NaCl not in 5% Dextrose

D5 insulin release K+ shift ICS

aggravates hypokalemia(0.2-1.4mEq/L)

20mEq/hr of K Cl raises K+ by

0.25mEq/L

80% of this enters cells.

HYPERKALEMIA (K+ > 5.5mEq/L)

Etiology

•Increased intake

I.V fluids containing potassium

I.V.fluids

Isolyte- M

Isolyte-P

Isolyte-G

Isolyte- E

Ringer’s

lactate

Potassium

(mEq/L)35.0 20.0 17.0 10.0 4.0

High potassium containing foods

Potassium containing Drugs

HYPERKALEMIA

• Tissue breakdown Bleeding into soft tissue, G.I.tract or body cavities

Hemolysis, Rhabdomyolysis

Catabolic State

• Shift of potassium Tissue damage

Metabolic acidosis

Uncontrolled Diabetes due to insulin deficiency

Aldosterone Deficiency

Hyperkalemic periodic paralysis, Succinylcholine

• Impaired Excretion Acute renal failure or chronic renal failure

Drugs : Potassium sparing diuretic, ACE inhibitors,

AT-II inhibitors, NSAIDS, heparin, cyclosporine

Reduced tubular excretion : Addison’s disease,

hyporeninemic hypoaldosteronism and amyloidosis

Effective circulatory volume depletion

• Pseuhohyperkalemia Traumatic haemolysis during blood drawing

Thrombocytosis, marked leucocytosis

HYPERKALEMIA

CLINICAL FEATURES

Muscle weakness hyporeflexia paralysis affecting legs,

trunk and arms (in that order) and at last respiratory muscles.

Muscles supplied by cranial nerves are spared

Cardiac Arrythmia

6-7 mEq/L : Tall peaked T waves

7-8 mEq/L : loss of P waves, widening of QRS complex

8-10 mEq/L : QRS merges with T waves forming sine

waves

>9mEq/L : AV dissociation, Ventricular tachycardia or

fibrillation , Diastolic arrest.

CLINICAL FEATURES

Lethal hyperkalemia during anaesthesia:

Reperfusion of a large vascular bed after a

period of ischemia. ( usually 4 hrs)

Ischemia acidosis shift of K+ from

ICF to ECF

TREATMENT

Stop exogenous sources : K+ containing IV fluids, drugs etc.

For mild elevation (5 to 6 mEq/L), remove potassium from the

body with

Diuretics : 40-80mg I.V

Cation exchange Resins:

Sodium polystyrene sulphonate (Kayexalate ) 15 to 30 g in 50 to

100 mL of 20% sorbitol either orally or by retention enema.

Exchange sodium for potassium in G.I.tract

Each gram binds 1mEq of K+ and releases 2-3mEq of sodium.

Caution : CHF and volume overload patients

…TREATMENT

For moderate elevation (6 to 7 mEq/L), shift

potassium intracellularly with

Glucose plus insulin: mix 25 g (50 mL of D50) glucose and 10-20 U

regular insulin and give IV over 15 to 30 minutes

Initial bolus followed by continuous infusion with

5% dextrose @ 100ml/hr to avoid late

hypoglycemia.

K+ falls by 0.5-1.5mEq/L. effect begins in 15 mins

and peaks at 60 mins. Lasts for 4-6 hours.

Sodium bicarbonate: 50 mEq IV over 5-10

minutes

less effective for treatment of patients with

renal failure : do not tolerate the sodium load

and resultant volume expansion

Nebulized albuterol: 10 to 20 mg nebulized

over 15 minutes or inj Salbutamol 0.5mg by

I.V.infusion

Preferred in ESRD for rapid lowering

Tachycardia : I.V therapy > nebulization.

…TREATMENT

Severe elevation (7 mEq/L with toxic ECG

changes) Calcium chloride (10%) 500 to 1000 mg (5 to 10 mL) IV

over 2 to 5 minutes or Calcium Gluconate 10% 10-

20ml over 5-10mins

to reduce the effects of potassium at the myocardial

cell membrane (lowers risk of ventricular fibrillation

[VF])

Avoid if patient is on digitalis.

…TREATMENT

TREATMENT

Dialysis

Hemodialysis: removal rate – 35mEq/hr

Peritoneal dialysis : 15 -20% as

effective as hemodialysis.

CALCIUM 10+/-0.5 mg/dl

Mediates :

Muscle contraction

Exocrine, endocrine and neurocrine

secretions

Cell growth

Transport and secretion of fluid and

electrolytes.

99% present in bones, 1% in cells and 0.15%

in ECF.

HYPOCALCEMIA

Weakness

Circumoral and distal paraesthesia

Muscle spasm : carpopedal spasm,

tetany.

Mental changes: irritability, depression

and psychosis.

CHOVSTEK’S SIGN

TROUSSEAU’S SIGN

ECG CHANGES

…. CLINICAL FEATURES

Severe hypocalcemia : lethargy,

confusion , laryngospasm, seizures or

irreversible heart failure.

Cataract and calcification of basal

ganglia.

TREATMENT Acute Management

10% calcium gluconate, : 10ml – 93mg of elemental

calcium

10% calcium chloride: 10ml - 273mg of elemental

calcium

10% calcium gluconate 10-20 ml IV over 10 minutes.

+ IV infusion of 540 to 720 mg of elemental calcium

(58 to 77 mL of 10% calcium gluconate) in 500 to 1000 mL

D5W @

0.5 to 2 mg/kg/ hour (10 to 15 mg/kg). OR

10% calcium chloride 5 mL () over 10 minutes, followed

by 36.6 mL (1 g) over the next 6 to 12 hours IV.

Measure serum calcium every 4 to 6hours.

Aim to maintain the total serum calcium

concentration at 7 to 9 mg/dL.

Correct abnormalities in magnesium, potassium, and

pH simultaneously.

Massive transfusion : for every 4 units of blood or

rate> 1.5ml/kg/min – 10ml of 10% calcium gluconate.

Extravasated calcium chloride – severe tissue

destruction : Calcium gluconate preferred for

peripheral venous administration.

TREATMENT

HYPERCALCEMIA

Serum calcium - 12 to 15 mg/dL.

Neurologic symptoms :

Depression, weakness, fatigue, and confusion at

lower levels.

At higher levels : Hallucinations, disorientation,

hypotonicity, seizures, and coma.

Renal

Polyuria , nocturia, stone formation

CLINICAL FEATURES Cardiovascular symptoms:

Upto 15mg/dl myocardial contractility increases

The QT interval typically shortens when the serum

calcium is> 13mg/dL.

PR and QRS intervals are prolonged.

Atrioventricularblock may develop and progress to

complete heartblock and even cardiac arrest when

the total serum calcium is > 15 to 20 mg/dL.

Hypercalcemia can worsen digitalis toxicity and

may cause hypertension.

CLINICAL FEATURES Gastrointestinal symptoms:

Dysphagia

Constipation

peptic ulcers, and

pancreatitis

Muscle weakness due to hypercalcemia:

decrease doses of non depolarising muscle

relaxant.

TREATMENT Treat if

Symptomatic and > 12mg/dl

>15mg/dl

Immediate therapy

Restore intravascular volume & promote excretion

infusion of 0.9% saline at 300 to 500mL/h (saline

diuresis) until any fluid deficit is replaced and diuresis

occurs (urine output 200 to 300 mL/h).

After adequate rehydration rate to 100 to 200 mL/h.

TREATMENT

Hemodialysis is the treatment of choice to rapidly

decrease serum calcium in patients with heart failure

or renal insufficiency.

Chelating agents (eg, 50 mmol PO4 over 8 to 12hours

or EDTA 10 to 50 mg/kg over 4 hours) may be used

for extreme conditions.

Furosemide (1 mg/kg IV) but avoid thiazide diuretics.

MAGNESIUM

Magnesium is the fourth most common mineral and

the second most abundant intracellular cation (after

potassium) in the human body.

Normal serum Mg2+ 1.8 – 3mg/dl

Magnesium is necessary for the movement of sodium, potassium, and calcium into and

out of cells

magnesium plays an important role in stabilizing

excitable membranes.

Mg2+ in ANAESTHESIA PNS –

interferes with release of neurotransmitters at all

synaptic juctions

Potentiates action of local anaesthetics.

Neuromuscular Junction

Significant presynaptic neuromuscular blockade

Enhance action of nondepolarizing muscle relaxant

Precipitate weakness in patients with myasthenia gravis

and Eaton-Lambert syndrome

Prolongs action of depolarizing neuromuscular blockers.

Prevents K+ release by succinylcholine

Mg2+ in ANAESTHESIA

Severe acute asthma – effective

bronchodilator

Obstetric practice

Powerful tocolytic – Manage premature

labour.

Prophylaxis and treatment of eclampsia.

HYPOMAGNESEMIA <1.8mg/dl

Muscular tremors and fasciculations

Ocular nystagmus

Tetany

Altered mental state

Cardiac arrhythmias such as torsades de

pointes (multifocal ventricular

tachycardia)

Ataxia, vertigo, seizures, and dysphagia.

TREATMENT For severe or symptomatic hypomagnesemia: 1

to 2 g of IV MgSO4 over 5 to 60 minutes.

Followed by continuous infusion of

1mEq/kg/24hours.

For torsades de pointes with cardiac arrest : 1

to 2 g of MgSO4 IV push over 5 to 20 minutes.

For seizures - give 2 g IV MgSO4 over 10 min.

Administration of calcium is usually appropriate

because most patients with hypomagnesemia

are also hypocalcemic.

Caution and monitoring MgSO4 therapy

Check deep tendon reflex every 15mins

(knee jerk)

Periodic monitoring of serum Mg

concentration.

Reduce dose in renal failure.

Contraindicated in heart block or extreme

myocardial damage

Maintain urine output – 100ml/4hours

Overtreatment 10% calcium gluconate 10-

20ml followed by fluid loading and diuretics.

TREATMENT

HYPERMAGNESEMIA (>3mg/dl)

Etiology

Renal failure patients : most common cause

Treatment of pre-eclampsia with I.V MgSO4.

ARF with acute rhabdomyolysis

Diabetic ketoacidosis without treatment.

CLINICAL FEATURES

Neuromuscular Manifestations

Muscular weakness muscular paresis leading

to respiratory depression and respiratory

failure.

No effect on central respiratory drive.

Cardiac manifestation

Hypotension: peripheral vasodilatation

Bradyarrhythmia

Cardiac asystole

ECG changes

Prolonged PR interval,

QRS duration and QT interval

Complete heart block

TREATMENT

Eliminate source

10% calcium chloride (5 to 10 mL [500 to 1000 mg] IV) or

10% calcium gluconate will often correct lethal arrhythmias.

IV saline diuresis (administration of IV normal saline and

furosemide [1 mg/kg]) can be used to increase renal

excretion of magnesium until dialysis can be performed.

Dialysis is the treatment of choice for severe

hypermagnesemia.

Artificial respiration

PHOSPHORUS

Major Buffer anion for ICF & ECF Rapid shifting can occur

Functions Muscle, red blood cells & nervous system

Maintains acid-base balance

Adequate renal function necessary to

maintain normal balance

90% excreted by kidneys

PTH regulates levels

Increases resorption from bone

Inhibits reabsorption in renal tubules

Increases absorption from GI tract

Calcium and phosphate or inversely

proportional

PTH = PO4³¯& Ca+

Normal: 2.8 - 4.5 mg /dl

HYPOPHOSPHATEMIA<2.8mg/dl

Paresthesia

Muscle pain/weakness

Acute respiratory failure

Confusion/coma

Cardiac: arrhythmias, decreased SV

TREATMENT

Diet/supplements (mild)

IV replacement (severe)

Major nursing role is teaching diet

Monitor for diarrhea if on supplements

Mix supplements with chilled/iced water

HYPERPHOSPHATEMIA (> 4.5mg/dl)

Tachycardia

Restlessness

Anorexia, Nausea and vomiting

Tetany

Tingling & numbness of fingers/lips

Muscle spasms

TREATMENT

Diet restrictions

Milk, meat,fish

Administer phosphate binding products

Calcium acetate and calcium

carbonate or aluminum hydroxide

Dialysis in severe renal failure.