Mcphs Clinical Therapeutics Fluid Management

Front 1

What is a normal osmolality range?

Back 1

275-295 mOsm/L

Front 2

What is the minimum Na+ required to replace losses (without sweating)?

Back 2

8mEq/day

Front 3

How much K+ is needed a day for adults?

Back 3

4.7g (120mEq/day) for adults

Front 4

What is considered hyperkalemia, and what are the complications associated with hyperkalemia?

Back 4

>5.0 mEq/L

Renal failure
Severe acidosis (pH) causes extracellular shifts of K
In conditions of tissue break down eg. massive trauma

Front 5

What are the signs and symptoms of hyperkalemia?

Back 5

Neuromuscular manifestations, cardiac irregularities

Front 6

What is the TX of hyperkalemia?

Back 6

Stop exogenous K

IV calcium gluconate given for sx patients to restore membrane excitability toward normal

Cause K to move intracellularly, insulin, sodium bicarbonate

Removal of K, Loop and thiazide diuretics, ion-exchange resins, dialysis

Front 7

a fall in the level of potassium in the blood may be due to
Increased loss:
In the urine e.g. following diuretics
Through the gastrointestinal tract e.g. following diarrhoea
Sweating
Decreased intake:
Fasting
The administration of potassium free IV fluids
Shift of potassium into cells:
Insulin therapy
Administration of antacids.

Back 7

Hypokalemia

Front 8

What are the maintenance fluid requirements for a normal adult?

Back 8

30-40mL/kg/day, BSA, 1mL/kcal

Front 9

Increase in solute concentration in one compartment (K in ICF) causes increase in

Back 9

osmolality which pushed fluid out into the ICF decreasing the ICF volume and increasing the ECF volume. This is how Na and K drive the osmotic gradient

Front 10

Increase in water in the ECF casues

Back 10

dillution of the osmolarity which then pushed water into the ICF. Overall both compartemetns increase in volume and osmolarity stays equal.

Front 11

(< 3.6 mEq/L)

Abnormal losses in urine or stool, ↓intake (malnutrition), transcellular shifts

Associated with metabolic alkalosis: K+ shifts from plasma to cells
Signs and Symptoms
Neuromuscular weakness
Irritability – stupor
ECG changes. Flat or inverted T wave
Cardiac arrhythmias - especially in patients on digoxin treatment
Paralytic ileus

Back 11

Hypokalemia

Front 12

How do you TX hypokalemia?

Back 12

Oral, KCl tabs, IV

Front 13

Used in developing world for diarrhea in children (50-100ml/kg)-WHO
Mild-moderately dehydrated adults drink up to 3L per day until urine output resolves

Continue eating normal diet

Used in short bowel syndrome to help with gut adaptation

Back 13

Oral Rehydration Solution

Front 14

Dextrose metabolized leaving free water-acts as a hypotonic fluid in the cell
Distributes proportionally into ECF and ICF
Treatment for rehydration after hypotonic fluid loss (correction of water deficit)
Used short term for rehydration
Caution with blood glucose

Back 14

D5W

Front 15

Isotonic

Used to expand the ECF volume (hypovolemic)
Renal excretion of NaCl
GI losses
Septic
Burns
Fluid losses during surgery
DKA

Does not contain other essential electrolytes

Back 15

Normal Saline

Front 16

Maintenance IVF when oral intake inadequate
Can add 20mEq/L potassium for effective maintenance fluid
Replacement fluid for GI drainage
Saline portion expands/maintains ECF
Electrolyte free portion distributes into both ICF and ECF

Back 16

Dextrose and Saline ( D5 ½ NS)

Front 17

0.45% NaCl expands the ICF-hypotonic

Dillute the ECF and push water into the ICF

Used for short term treatment of hypernatremia, DKA, cellular dehydration (excessive diuresis)

Back 17

½ NS

Front 18

How do you handle fluid replacement with diabetic ketoacidosis?

Back 18

Patient need immediate intravascular fluid resuscitation (between 1-3L in adults).

Once BP WNL, NS replaced with hypotonic fluid (1/2 NS) to help replete intracellular dehydration.

When glucose drops below 250 g/dL replace fluids with maintenance (d5 ½ NS)

Front 19

3% or 5% NaCl-hypertonic
Volume resuscitate ECF
Increases osmolality of the ECF drawing fluid out of the ICF

Used for severe hyponatremia, brain injury, volume resuscitation (sepsis)

Use with caution: hypernatremia, hyperosmolarity, brain cell depletion and neurological damage

Back 19

Hypertonic Saline

Front 20

Uses
Replacement of fluid – ECF volume expansion
Maintenance of fluid and electrolyte needs
Medicine administration
Lactate must be converted into bicarbonate in the liver

Not recommended for pts with severe acidosis or liver dz
May worsen lactic acidosis

Back 20

Lactaid Ringers

Front 21

Isotonic fluids expand the

Back 21

ECF

Front 22

Hypertonic fluids expand the

Back 22

ECF, but also pull fluid from the cells (ICF)

Front 23

Hypotonic fluids expand primarily

Back 23

the ICF, but also the ECF

Front 24

electrolyte losses are greater then fluid losses

Back 24

Hyponatremic dehydration

Front 25

Serum Na+ <135 mEq/L

Back 25

Hyponatremic dehydration

Front 26

Sx: lethargy, headache, nausea, vomiting, muscle cramps, restlessness, disorientation, depressed reflexes, personality changes, seizures

Back 26

Hyponatremic Dehydration

Front 27

Hyponatremia usually reflects

Back 27

hypoosmolality, it can also occur with normal or elevated effective plasma osmolality

Front 28

what's the correction rate for Hyponatremia

Back 28

5-10meq/kg/day increase in plasma Na+ per day
1-2 meq/hr

Front 29

Elevated plasma osmolarity and low serum Na level.
Gluc and BUN are active solutes that if elvated increase the plasma osmolarity
i.e: poorly controlled DM
Drawing water from the muscle cells into the vascular space= hyponatremia.
Glucose produces a drop in the serum sodium level of 1.6 mEq/L for each 100 mg/dL of serum glucose greater than 100 mg/dL.

Back 29

Hypertonic Hyponatremic

Front 30

↓Total body Na+
↓ ↓ Total body water

Symptoms
Tachycardia
↓BP
↓skin turgor

Renal Losses
1.Diuretic
2.Osmotic diuresis
3.Salt wasting nephropathy

Back 30

Hypotonic hypovolemic hyponatremia

Front 31

Dysfunction of increase in release of ADH by pituitary gland

Water retention, dilution hyponatremia

Sx-hyponatremia and concentrated urine, no edema (Urine osmolality>300mOsm or Urine Na concentration >20 mEq/L)

Causes: brain/ CNS injury, infection, lung process, cancer, idiopathic

Tx-underlying problem, fluid restriction, hypertonic saline (3%), diuretics

Back 31

SIADH

Front 32

Volume Overload
↑Total body Na+
↑ ↑ Total body water

Symptoms
Edema

1.Nephrotic syndrome
2. CHF
3.Hepatic cirrhosis

Back 32

Hypotonic Hypervolemic Hyponatremia

Front 33

Loss of pure water from both ICF and ECF
Etiology:
Increased insensible water loss (fever, mechanical ventilation, burns)
Aggressive diuresis
Diabetes insipidus
Manifestations of pure water loss reflect both volume depletion & hypernatremia leads to hypertonic
Na + >145 meq/L sx: confusion, stupor, increased neuromuscular irritability and twitching, seizures. Also sx of volume depletion

Back 33

Hypernatremic Dehydration

Front 34

How do you correct hypernatremia?

Back 34

The plasma Na+ should be lowered by no more then 0.5 mEq/L/hr
No more then 10 mEq/L/day
Safest route is with oral or feeding tube water administration
Alternatively IV D5W or ½ NS

Front 35

Volume Depletion
↓Total body Na+
↓ ↓ Total body water

Extrarenal Losses
1.Profuse sweating
2. Severe diarrhea
3.Respriratory losses

Renal Losses
1. Diuretics
2. Glycosuria
3. Obstructive uropathy
4. Acute/Chronic renal failure

Back 35

Hypovolemic Hypernatremia

Front 36

diabetes insipidus, central is caused by a deficiency of ?

The second common type of DI is nephrogenic diabetes insipidus, which is caused by

Back 36

1. deficiency of antidiuretic hormone (ADH).


2. an insensitivity of the kidneys to ADH. It can also be induced iatrogenically by various drugs.