Sensory Perception and Electrolytes

Chap. 24

100

Loop or high-ceiling are most effective diuretics

Mechanism of action: to block reabsorption of sodium and chloride in loop of Henle

to reduce edema associated with heart, hepatic cirrhosis, or renal failure

furosemide

fyr·ow·suh·mide

200

 Thiazide Diuretics Mechanism of action: to block Na+ reabsorption and increase potassium and water excretion

• Primary use: to treat mild to moderate

hypertension

– Also indicated to reduce edema associated with

heart, hepatic, and renal failure

hydrochlorothiazide

hai·druh·klaw·ruh·thai·uh·zide

300

Potassium-Sparing Diuretics

• Advantage: diuresis without affecting blood potassium levels

• Mechanism of action: either by blocking sodium or by blocking aldosterone, the hormone that controls renal reabsorption of

sodium and potassium

spironolactone

spai·ruh·now·lak·town

400

Miscellaneous Diuretics: osmotic diuretic

treat the low output of urine associated with kidney failure

– reduce elevated pressure in the brain (cerebral edema) and in the eyes

– also promotes the excretion of substances such as aspirin and barbiturates in overdose situations

mannitol
ma·nuh·taal

500

Loop (High-Ceiling) 

Thiazide and Thiazide-like 

Potassium-Sparing

Different Types of Diuretics

Chap. 25

100

Hypertonic-interstitial space to plasma
Hypotonic-plasma to interstitial space 

Isotonic-No fluid shift

Types of Osmosis

200

Colloids- raise oncotic pressure of blood; expands plasma volume

within minutes of administration

fluid replacement with

hypovolemic shock from hemorrhage,

surgery, severe burns

• Adverse effects: hypersensitivity

reactions, fluid overload, hypertension

dextran 40 (Gentran 40, LMD, others)

deks·tran

 

300

electrolytes

sodium supplement

• Primary use: to treat hyponatremia when

serum levels fall below 130mEq/L

• Adverse effects: hypernatremia and

pulmonary edema

sodium chloride (NaCl)

400

Electrolytes• Mechanism of action: as electrolyte/

potassium supplement

• Primary use: to treat hypokalemia

• Adverse effects: GI irritation,

hyperkalemia; contraindicated in patients

with chronic renal failure or those taking

potassium-sparing diuretic

potassium chloride

(KCl)

500

Acid–Base Agents

• Mechanism of action: to decrease pH of

body fluids

• Primary use: treatment of acidosis

• Adverse effect: metabolic alkalosis caused

by receiving too much bicarbonate ion and

hypokalemia

sodium bicarbonate

Chap. 29

100

Hypovolemic: from loss of blood volume

• Neurogenic : from vasodilation due to

changes in autonomic nervous system

• Cardiogenic : from failure of heart to

pump sufficient blood

• Anaphylactic : from severe reaction to

an allergen

Septic 

– Multiple-organ dysfunction

– Result of pathogenic organisms in blood

– Causes vasodilation and changes in permeability

of capillaries

– Often precursor to acute respiratory distress

syndrome (ARDS) and disseminated

intravascular coagulation (DIC)

Types of Shock

200

Mechanism of action: to maintain plasma
osmotic pressure; transport substances
through blood
• Primary use: restoration of plasma volume
and blood proteins

serum albumin Dextran
 

Colloid Agents

300

Intravenous solutions that contain

electrolytes

• Concentrations resembling those of plasma

• Mechanism of action: Can readily leave

blood and enter cells

 normal saline, lactated

Ringer's, D5W, and hypertonic saline

Crystalloids

400

Positive inotropic effects

• Primary use: to treat shock and cardiac

arrest

• Examples: dopamine, norepinephrine,

phenylephrine, epinephrine

Vasoconstrictors/Vasopressors

500

Replace plasma volume and supply red blood

cells

– Components

 Whole blood, plasma protein fraction

 Fresh-frozen plasma, packed red blood cells

 Know the signs and symptoms of circulatory

overload(dyspnea) and blood transfusion reaction

(flushing).

Blood or blood products

Chap. 50

100

• Also called acute or narrow-angle glaucoma

• Accounts for 5% of all glaucoma

• Usually unilateral; caused by

– Stress, impact injury, or medications

• Iris pushed over drainage area; causes

angle to narrow and close

• Causes sudden increase in IOP

Closed-angle Glaucoma

200

• Accounts for 90% of cases

• Usually bilateral

• IOP develops slowly over years

• Asymptomatic

• Iris does not cover opening

• Treated with medications

Open-angle Glaucoma

300

Mechanism of action: believed to reduce

IOP by increasing outflow of aqueous humor

• Primary use: to treat open-angle

glaucoma

ostaglandins

• Adverse effects: conjunctival edema,

tearing

– Dryness, burning, pain, irritation

– Itching, sensation of foreign body in eye

– Photophobia and/or visual disturbances

– Eyelashes on treated eye may grow thicker

and/or darker

– Changes in pigmentation of iris of treated eye

and periocular skin

latanoprost (Xalatan) 

luh·ta·nuh·praast

400

• Mechanism of action: reduces formation

of aqueous humor

• Primary use: to reduce elevated

intraocular pressure in chronic open-angle

glaucoma

• Adverse effects: local burning and

stinging upon instillation

timolol (Timoptic,

Timoptic XE)

tai·muh·laal

500

is the most common reaction in drugs

Don't overthink it.

hypersensitivity 

Misc.

100

KNOW: NS, LR, D5W for prototypes

Used to replace fluids and promote urine
output
• Capable of leaving plasma and moving to
interstitial spaces and intracellular fluid
• Compartment entered depends on tonicity
of intravenous fluid

Crystalloids

200

Sodium level above 145 mEq/L

• Most commonly caused by kidney disease

• Sodium accumulates

– Decreased excretion

– High net water loss (watery diarrhea, fever,burns)

– High doses of corticosteroids or estrogens

Signs and symptoms

– Thirst, fatigue, weakness, muscle twitching

– Convulsions, altered mental status, decreased level of consciousness

Can be treated with low-salt diet
• Acute hypernatremia treated with hypotonic
intravenous fluids (if hypovolemic) or
diuretics (if hypervolemic)

Hypernatremia

300

Sodium level below 135 mEq/L

• Caused by excessive dilution of plasma

– Excess antidiuretic hormone (ADH) secretion

– Excessive administration of hypotonic

intravenous solution

• Vomiting, diarrhea, gastrointestinal suctioning, diuretic use

Early symptoms

– Nausea, vomiting, anorexia, abdominal

cramping

• Later signs

– Altered neurologic function such as confusion,

lethargy, convulsions, coma, muscle twitching,

tremors

Hyponatremia caused by excessive dilution

– Treat with loop diuretics to cause an isotonic

diuresis

• Hyponatremia caused by sodium loss

– Treat with oral sodium chloride or intravenous

fluids containing salt

 Normal saline

 Lactated Ringer's

Hyponatremia

400

Potassium level above 5 mEq/L

• Caused by high consumption of potassium-

rich food, dietary supplements

• Risk with patient taking potassium-sparing

diuretics

• Accumulates when renal disease causes

decreased excretion

Most serious are dysrhythmias and heart

block

• Other symptoms are muscle twitching,

fatigue, paresthesias, dyspnea, cramping,

and diarrhea

Restrict dietary sources

• Decrease dose of potassium-sparing

diuretics

• Administer glucose and insulin

• Administer calcium to counteract potassium

toxicity on heart

• Administer polystyrene sulfonate

(Kayexalate) and sorbitol to decrease

potassium levels

Hyperkalemia

500

Potassium level below 3.5 mEq/L
• Caused by
– High doses of loop diuretics
– Strenuous muscle activity
– Severe vomiting or diarrhea 

Neurons and muscle fibers most sensitive to
potassium loss
• Muscle weakness, lethargy, anorexia,
dysrhythmias, cardiac arrest 

Mild—Increase dietary intake

• Severe—Give oral or parenteral potassium

supplements

Hypokalemia