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Diuretics and fluid electrolytes volume ch.41-42
Terms in this set (61)
What is the basic function unit of the kidney?
Why are the kidneys important?
cleanses and Maintain ECF volume and composition
Maintain Acid base balance
Excretion of metabolic wastes and foreign substances
What are the 4 parts that makes up a nephron?
-.Proximal convoluted tubule
-loop of Henle
-Distal convoluted tubule
What are the 3 basic renal processes?
1.filtration (occurs at glomerulus;
2. Reabsorption (occurs at different parts of nephron
3. Active tubular secretion (proximal convoluted tubule and diuretics work by disrupting process)
Are drugs that increase urinary output.
What are the 2 reasons why diuretics are used?
1. Treat hypertension
2. Mobilization of edematous fluid to prevent renal failure.
What is the Mechanism And site of Action for Diueretics?
-MOA: blockade of Sodium and chloride reabsorption.
-SOA: the proximal tubule (produces greatest diuresis)
What are the adverse effects of diuretics?
1. Hypovolemia (dehydration)
2. Acid base balances
3. Electrolyte imbalances
What are the classifications of Diueretic drugs?
1. High ceiling (loop)
2. Thiazides (
) ex. Hydrochlorothiazide
3. Osmotic (
) ex. Mannitol
4. Potassium sparing
-aldosterone antagonist ex. Spironlactone
-non aldosterone antagonist ex. triamterene
5. Carbonic anhydrase inhibitors (used to lower Intraoccular pressure like glaucoma)
Before administering a diuretic what do you have to do first?
1. Pre-administration assessment (ex. Focused assessment, allergies, renal and ear function check PMH, check home medications, etc)
2. Know your pts. Normal baseline values (kidney lab values, vitals, Electrolytes, intake and outtake, weight, etc.)
3. scheduled doses
What are the 4 loop diuretic drugs?
40 times more potent than furosemide
-Ethacynic acid (Edecrin)
the oldest drug and has more side effects and is usually considered the last resort
What diuretic treats Premenstrual dysphoric disorder is also a fluid retaining disorder with homicidal tendencies?
promotes diuresis with poor renal blood flow to afferent/efferent GFR
, profound diuresis (
increase blood Filtration and Increase urinary output
Site of Action:
Ascending loop of Henle
(blocks resorption of sodium and chloride, preventing passive reabsorption of water)
(PO 60 min, IV 5min)
Uses: CHF, Pulmonary edema, HTN, Edematous state, cirrohsis
watch for hypokalemia
advise about foods high in potassium
if taking 2 a day take at 8 and 2pm to minimize nocturia
What are the adverse effects of Furosemide (lasix)?
- loss of volume, relaxation of venous smooth muscle
-loss of water, start with low doses, weight daily initially
-Increases LDL, cholesterol and triglycerides, decreases HDL
Postural hypotension, blurred vision, anorexia, photosensitivity
, Ototoxic drugs,
What is the purpose of a Thiazide Diuretic? What drugs are used?
than furosemide (Lasix)
Increased renal excretion of sodium, chloride, potassium, and water, elevate levels of uric acid and glucose
-As an important aside, calcium excretion is regulated by parathyroid hormone.
Calcium and sodium compete for excretion at the DCT; sodium is excreted, calcium is reabsorbed
good for the bones especially in osteoporosis pts.
(Hydrodiuril), chlorthalidone, chlorothiazide (Diuril), indapamide (Lozol), and metolazone (Zaroxolyn).
Site of Action: the
distal convoluted tubule (DCT) by inhibiting another transporter system—sodium/chloride transporter system
m*. About 10% of the filtered sodium is reabsorbed through this system.
What are some considerations with Thiazides?
Hyponatremia, hypochloremia, dehydration
-Effects for antihypertension 2-4 weeks
Increased uric acid levels
-can precipitate diabetes
Increased levels of cholesterol and triglycerides
Augments effects of hypertensive medications
reduce renal excretion of lithium (leading to accumulation)
-Most widely used
Cannot be used to promote fluid loss in patients with severe renal impairment
-Site of Action:
Action-distal convoluted tubule
Peaks 4-6 hours
-Used to treat:
- head injury, increase UO, decrease ADH (posterior pituitary)
What is the purpose of Potassium Sparing diuretics? What are the drugs mostly used?
The weaklings of diuretics.
increase in urine production
Substantial decrease in potassium excretion
-Rarely used alone for therapy
-If aldosterone is inhibited, sodium heads into the toilet and potassium is conserved. This is all fine and dandy until other K+ conserving drugs, the ACE inhibitors, are given simultaneously.
in addition of K sparing diuretics
-Nonaldosterone antagonists -
Blocks sodium-potassium exchange in the distal nephron
What is the adverse effects of a potassium sparing diuretic? What are some restrictions?
. If serum potassium rises above 5mIq/L, discontinue medication and restrict potassium intake. Injection of insulin can help lower potassium levels by promoting uptake into cells
Restrict potassium rich foods
-nuts, dried fruits, spinach, citrus fruits, potatoes, bananas
What drug can treat hyperkalemia and Promotes potassium excretion and sodium reabsorption in the large intestine?
-Can be given orally or rectally (enema)
-Retain solution for 30-60 minutes
Blocks aldosterone in the distal nephron
Retention of potassium, increased sodium excretion
-use for hirsutism in women, causes gynecomastia in men
Severe heart failure
( blocks aldosterone in adrenal cortex)
Polycystic ovary syndrome
(produce increase androgen)
Acne in young women
What is the normal lab value range for potassium?
-Parenteral agents causes diuresis by adding to the solutes already present in the tubular fluid,
particularly effective in increasing osmotic pressure (osmolity) because they are not reabsorbed by the tubules
(pulling fluids from cells)
Used to treat cerebral edema (head trauma-ICP) & IOP secondary glaucoma
-Nursing Interventions: Indwelling catheter is used to monitor I & 0
What are the Main adverse effects of diuretics?
Electrolyte losses, dehydration, N,V,D, dizziness, hyperglycemia, hyperuricemia
More sensitive to diuretic→ F&E, hypotension
Start with lowest dose possible-usually ½ the normal adult dose
-Drink fluids unless fluid restriction
-Avoid concurrent administration of a potassium supplement especially if on K+ sparing
-Diuretics will increase urinary incontinence
Reduce the drug gradually when it is discontinued to avoid development of fluid retention & edema
What is the purpose of Fluid Volume and Osmolality? What are the reasons why drugs are used for fluid volume/ osmolality?
Good health requires that both the volume and the osmolality of extracellular and intracellular fluids remain within a normal range
Maintenance of both is primarily the job of the kidneys
Volume contraction and volume expansion
correct disorders of fluid volume and osmolality
correct disturbances of hydrogen ion concentration
correct electrolyte imbalances
What are the disorders regarding fluid volume and osmolality?
-Abnormal states of hydration
-Two major categories volume contraction, expansion
Volume contraction is a decrease in total body water
-Treat with volume expanders
Volume expansion is an increase in total body water
-Treat with diuretics and agents used for heart failure
same as body fluids
expand intravascular volume, treat hypotension resulting from hypovolemia
lower serum osmolality by causing fluid to shift out of blood and into cells and interstitial spaces
Can lower BP and cause hemolyzes of RBCs
0.45% Normal Saline
raise serum osmolality by causing a pull of fluids from the intracellular and interstitial compartments into the blood
. Expand the intravascular compartment and are administered when there is a serious saline depletion.
Can cause circulatory overload
10% Dextrose in Water
what is an isotonic contraction?
-Volume contraction in which
sodium and water are lost in isotonic proportions
-Decrease in total volume, but no change in osmolality
What causes a isotonic contraction?
Vomiting, diarrhea, kidney disease, and misuse of diuretics
How do you treat an isotonic contraction?
Fluids that are isotonic
prevent pulmonary edema
What is a hypertonic contraction?
Loss of water exceeds loss of sodium
-Reduced extracellular fluid volume and increase in osmolality
What causes a hypertonic contraction?
Excessive sweating, osmotic diuresis
, concentrated food given to infants
Secondary to extensive burns
or CNS disorders that interfere with thirst
How do you treat a hypertonic contraction?
Hypotonic fluids or fluids that contain no solutes at all (D5W)
What is hypotonic contraction?
Loss of sodium exceeds loss of water
-Both volume and osmolality of extracellular fluid are reduced
What causes the hypotonic contraction?
Excessive loss of sodium through the kidney (
diuretic therapy, chronic renal insufficiency, lack of aldosterone
What treats hypotonic contraction?
infusing isotonic sodium chloride solution
hypertonic solution (3%) NaCl
Watch for signs of fluid overload
What is volume expansion?
Increase in the total volume of body fluid
-May be isotonic, hypertonic, hypotonic
What causes volume expansion?
-Overdose with therapeutic fluids
Disease states (congestive heart failure [CHF], nephrotic syndrome, cirrhosis with ascites)
What treats volume expansion?
Agents used for heart failure
Acid Base Disturbance
-Acid base status is regulated by the bicarbonate carbonic acid buffer system
-Respiratory (CO2 increase - lowers pH)
-Kidneys (HCO3- increase raises pH)
Normal pH: 7.35-7.45
-Body will work to maintain this pH through
use of breathing and fluid excretion
What are some acid base disturbances?
-Respiratory alkalosis (pH increases, PCO2 decreases)
-Respiratory acidosis (pH decreases, PCO2 increases)
-Metabolic alkalosis (pH increases, HCO3 increases)
-Metabolic acidosis (pH decreases, HCO3 decreases)
Caused by hyperventilation
-Elevation of pH
-Hypoxia, pulmonary disease, drugs, injury to the CNS, hysteria
If severe, breath into bag to rebreath CO2
Retention of CO2, secondary to hypoventilation
-Depression of medullary respiratory center
-Pathologic changes in the lungs
-Treat by treating reason for hypoventilation,
HCO3- if severe
Increase in pH and bicarbonate content of plasma.
Causes excessive loss of gastric acid
-Suctioning of stomach
-Body compensates by hypoventilation, increased renal excretion of bicarbonate, accumulation of organic acids
Sodium chloride, potassium chloride
Chronic renal failure, severe diarrhea, metabolic disorders
(lactic acidosis, ketoacidosis), overdose of ASA, poisoning
Find and treat underlying cause
Administer sodium bicarbonate
What are the major electrolytes?
Magnesium-important for function of body's enzyme systems
Plays an important role in muscle contraction, conduction of nerve impulses, enzyme action and cell membrane function
impaired skeletal muscle function, weakness, paralysis including respiratory muscles
met acidosis, EKG changes
Watch in clients with: renal failure, hydration imbalance, acid-base imbalance, cellular damage, burns, accidents, surgeries, and diabetes
What is the normal lab value for sodium?
136-145 mEq/L plasma.
In what ways can you regulate the potassium levels?
Primarily by the kidneys
increased by aldosterone
increased by most diuretics
-Potassium-sparing diuretics are the exception
-Influenced by extracellular pH
-Alkalosis potassium uptake enhanced
-Acidosis potassium exits cells
Insulin has a profound effect on potassium level
Control content of body water
, electrophysiology of nerve, muscle and gland cells, and for the regulation of pH and isotonicity
: lethargy, hypotension, stomach cramps, vomiting, diarrhea, seizures
: edema, red & flushed skin, dry & sticky MM, increased thirst, elevated temp, anuria
What do you use to treat sodium disorders?
treated with Ringers solution or normal saline
reduce salt intake & administer dextrose IV to promote diuresis
increase the excretion of both salt and water from the blood
If a patient is undergoing Potassium replacement what should you make sure of?
IV potassium must always be diluted and administered under close supervision
pt. Must have adequate urine output.
Parenteral fluids should not contain more than 40 mEq/L of potassium
Oral administeration is safest
. Liquid can be diluted in juices
If a patient is undergoing hyperkalemia what should you do?
give meds that promote potassium excretion
diuretics, kayaxelate, insulin/glucose
withhold foods with potassium
Needed for growth
and ossification of bones, neuromuscular transmission, cell membrane permeability, maintenance of excitability in nerve fibers, hormone secretion and action, muscle contraction, maintenance of cardiac and vascular tone, enzyme activities, normal coagulation of blood
increases excitability of nerves and neuromuscular junction leading to muscle cramps, twitching, tetany, numbness, tingling of fingers, toes, lips
weakness, apathy, depression, EKG changes
What is the normal lab value for Magnesium?
What is the treatment for hyper/hypocalcium?
treat with IV calcium, best to give orally
treatment aimed at controlling underlying cause
-Required for the activity of many enzymes
-Binding of messenger RNA to ribosomes
Hypo-diarrhea, malabsorption, starvation, kidney disease, prolonged IV feeding, chronic alcoholism
Tetany, muscle spasms, delirium, dysrhythmias
Flushing, sweating, hypothermia, areflexia, paralysis, depression of cardiac, resp and CNS functions
What is the normal lab value for Calcium?
What are the treatments for hypo/hypermagnesium?
Hypo-IV magnesium 10-40 mEq/day
Hyper-treat with IV calcium, dialysis if severe
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