fluid and electrolyte management
TRANSCRIPT
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.