Surg 126--Chapter 7 Flashcards
Medications administered to prevent reabsorption of sodium and water by the kidneys?
Diuretics
Diuretics are used in the management of several chronic medical conditions, such as…
Hypertension, congestive heart failure (CHF), and glaucoma
What are electrolytes?
- Minerals that are dissolved in body fluids
- Develop an electrical charge when dissolved in water
- Found inside and outside of cells
- Acquired through food and water
What are the major body electrolytes?
- Sodium
- Potassium
- Calcium
- Chlorine
- Magnesium
- Bicarbonate
- Phosphate
- Sulfate
Condition in which potassium may be seriously depleted in patients taking certain diuretics.
Hypokalemia
Potassium levels that are either too low or too high may cause…
Cardiac dysrhythmias
Short-term use of diuretics is indicated when?
A condition requires rapid but temporary reduction in fluid
Why are diuretics used during surgery?
To reduce intraocular pressure, intracranial pressure, or to protect kidney function
How do diuretics lower blood pressure?
By increasing the elimination of fluids (water, sodium, and electrolytes) from the body; decreasing blood volume
Are diuretics administered from the back table?
No
Why are diuretics important to the ST?
- Long-term diuretic therapy may cause the delay or rescheduling of a surgery.
- Short-term intraoperative use of diuretics requires the insertion of an indwelling urinary catheter
The primary function of the renal system is to _____?
maintain homeostasis
How does the renal system maintain homeostasis?
By filtering blood and removing excess water and dissolved substances (or solutes) such as sodium and potassium
A microscopic filtering unit that removes water and waste solutes
nephron
Where does filtration occur in the nephron?
The Bowman’s capsule
The process of forcing fluids and solutes through a membrane by pressure.
filtration
Where does tubular reabsorption take place?
proximal convoluted tubule and the ascending and descending limbs of the loop of Henle
Eliminates waste products and controls blood pH.
tubular secretion
Diuretics cause elimination of excess fluid by preventing reabsorption of _____ and _____, increasing urine output.
sodium and water
How are diuretics classified?
- site of action
- mechanism by which the solute is altered
Highly potent diuretics used to remove fluid arising from renal, hepatic, or cardiac dysfunction and to treat acute pulmonary edema.
Loop diuretics
Loop diuretics inhibit the reabsorption of _____ to _____ of the sodium load.
20% to 30%
What is the most common cardiac dysfunction requiring treatment with diuretics?
CHF
The oral form of high-ceiling diuretics may be used to treat _____.
hypertension
Loop diuretics work by decreasing the reabsorption of _____ and _____ ions along the whole renal tubule, especially the loop of Henle.
sodium and chloride
Loop diuretics include:
- bumetanide (Bumex)
- ethacrynic acid (Edecrin)
- torsemide (Demadex)
- furosemide (Lasix)
What is the most commonly used loop diuretic?
furosemide
Furosemide:
- useful in intracranial procedures
- onset of diuresis in 5 to 15 minutes, will continue for 2 hours
- initial dose is 20 to 40 mg, given over 1 to 2 minutes
- second dose may be administered 2 hours later
Furosemide decreases intracranial pressure by quickly removing _____ that accumulates in response to trauma of the cranium
fluids
Low potency diuretics used to treat essential hypertension and mild chronic edema.
Thiazide diuretics
Thiazide diuretics inhibit the reabsorption of _____ to ______ of the sodium load.
5% to 10%
Thiazide diuretics work by inhibiting the reabsorption of sodium and chloride in the end of the _____ of the nephron and the beginning of the _____.
ascending loop
distal convoluted tubule
Examples of thiazide diuretics:
- bendroflumethiazide (Naturetin)
- chlorothiazide (Diuril, SK-Chlorothiazide)
- hydrochlorothiazide
Low potency diuretics commonly used to treat edema and hypertension and to help restore potassium levels in hypokalemic patients.
Potassium-sparring drugs
Potassium-sparring diuretics inhibit only _____ to _____ of the sodium load.
1% to 3%
Usually administered in combination with other diuretics such as thiazides and loop diuretics to minimize potassium loss.
Potassium-sparring drugs
Potassium-sparring drugs prevent the reabsorption of sodium in the _____ by altering membrane permeability.
distal convoluted tubule
Examples of potassium-sparring drugs include:
- amiloride (Midamor)
- spironolactone (Aldactone)
- eplerenone (Inspra)
- triamterene (Dyrenium)
Adverse effects of potassium-sparring drugs includes _____.
hyperkalemia
Low potency diuretics used to treat mild acute closed-angle glaucoma and chronic open-angle glaucoma and lowers intraocular pressure.
Carbonic anhydrase inhibitors
Carbonic anhydrase inhibitors act on the _____, so urine output is not significantly changed.
proximal convoluted tubule
The most common carbonic anhydrase inhibitors
acetazolamide (Diamox)
Highly potent and increase blood pressure and volume by drawing fluid out of tissues and into the circulatory system rapidly.
Osmotic diuretics
Contraindicated in patients with hypertension and edema.
Osmotic diuretics
The most common osmotic diuretic
mannitol (Osmitrol)
May be used to provide rapid reduction in intraocular pressure in patients experiencing acute angle-closure glaucoma
mannitol (Osmitrol)
Cause the highest rate of potassium loss.
thiazide and loop diuretics
One of the essential minerals needed by the body to maintain homeostasis.
potassium
One of the most abundant minerals found in the body.
potassium
Normal level of potassium
3.5 to 5.0
Best method for treatment of hypokalemia
oral replacement
mineralocorticoid hormone produced by the adrenal cortex
aldosterone
Increases the reabsorption of sodium and water and the secretion of potassium in the kidneys.
aldosterone
Increases blood volume and thus blood pressure
aldosterone
Primary intracellular electrolyte in the body
potassium
plats a vital role in many body functions, such as nerve impulse conduction, acid-base balance, ad promotion of carbohydrate and protein metabolism
potassium
