Exam 2
Angiotensin-converting enzyme (kinase II)
-Catalyzes the conversion of angiotensin I (inactive) to angiotensin II (highly active) -Involved in the breakdown of bradykinin
Hypertonic contraction
-Loss of water > loss of sodium -Reduced ECF volume -Increase in osmolality
Magnesium
-Serum ____________ levels 1.8-3.0 mg/dl Actions: -Required for activity of many enzymes -Binding of messenger RNA to ribosomes Functions to regulate: -Transmission -Excitability
Hypomagnesemia
-Serum magnesium <1.8 mg/dl Causes: -Diarrhea -Hemodialysis -Kidney disease -Poor nutritional states
Hypermagnesemia
-Serum magnesium >3.0 mg/dl -Most common with renal insufficiency (RI)
Isotonic contraction
-Sodium and water are lost in isotonic proportions -Decrease in total volume -No change in osmolality
c.) Reflex tachycardia (quickest response)
A patient is prescribed a medication that lowers the arterial blood pressure. The nurse should assess for which response by the body to restore the blood pressure? a.) Orthostatic hypotension b.) Fluid retention (later response) c.) Reflex tachycardia (quickest response) d.) Increased natriuresis
Hydrochlorothiazide (HCTZ)
AKA "HCTZ" Most widely used thiazide Common uses: HTN Edema
Cardiac afterload
AP that the left ventricle must overcome to eject blood
Aldosterone
Actions of _____________ -Regulation of blood volume and blood pressure -Pathologic cardiovascular effects: Remodeling, fibrosis, dysrhythmias
Spironolactone
Aldosterone antagonist Common Uses: -HTN -Edema -Heart failure (HF/CHF) -Primary hyperaldosteronism -Premenstrual syndrome (PMS) -Polycystic ovary syndrome (PCOS) -Acne
Rapid control by ANS: Baroreceptor reflex
Attempts to keep PR at a predetermined level
Hyperkalemia
Can be used to treat low extracellular levels of potassium, due to ______________________. -Oral or rectal administration sodium polystyrene sulfonate [Kayexalate®] -Calcium salt -Insulin -Dialysis -Sodium bicarbonate
Metabolic Acidosis
Causes: -Chronic renal failure -Loss of bicarbonate -Metabolic disorders -Poisoning by methanol -Certain medications Treatment: -Correction of the underlying cause of acidosis -If severe: alkalinizing salt
Hypotonic contraction
Causes: -Excessive loss of Na through kidneys Treatment: -Mild: Isotonic NaCl infusion (NS) -Severe: Hypertonic solution (3% NaCl) -Watch for signs of fluid overload
Metabolic Alkalosis
Causes: -Excessive loss of gastric acid -Administration of alkalinizing salts -Severe volume contraction Treatment: -Solution of sodium chloride plus potassium chloride
Hypertonic contraction
Causes: -Excessive sweating, osmotic diuresis, 2nd to extensive burns, etc. Treatment: -Hypotonic fluids (0.45% NaCl) or fluids that contain no solutes at all -Initial therapy: Drink water
Respiratory Alkalosis
Causes: -Hyperventilation --> decrease in CO2 Treatment: -Mild: None needed -More severe: Rebreathe CO2-laden expired breath
Volume expansion
Causes: -Overdose with therapeutic fluids -Disease states Treatment: -Diuretics -Select agents (HF)
Respiratory Acidosis
Causes: -Retention of CO2 secondary to hypoventilation Treatment: -Correction of respiratory impairment -Infusion of sodium bicarbonate if severe
Hyperkalemia
Causes: -Severe tissue trauma -Untreated Addison's disease -Acute acidosis -Misuse of potassium-sparing diuretics -Overdose with IV potassium Consequences: -Disruption of cardiac electrical activity -Earliest signs of danger: Mild (5-7 mEq/L) Severe (8-9 mEq/L) -Noncardiac signs: Confusion, anxiety, dyspnea, weakness or heaviness of legs, paresthesias (hands/feet/lips)
Isotonic contraction
Causes: -Vomiting, diarrhea, kidney disease, and misuse of diuretics Treatment: -Fluids that are isotonic to plasma -0.9% NaCl -Replenish slowly
Hyokalemia
Causes: -meds Adverse effects: -Seen in skeletal & smooth muscle, BP, and EKG changes -Increases risk for HTN and stroke (CVA)
Cardiac preload
End-diastolic volume or end-diastolic pressure
acidic
HCO3 less than 22 is _____________
alkaline
HCO3 more than 26 is _____________
Insulin
Has profound effect on potassium levels
Cardiac Output
Heart Rate x Stroke Volume
-Constricts renal blood vessels -Acts on the kidney to promote retention of sodium and water and excretion of potassium
How does the RAAS help to regulate the BP?
Volume expansion
Increase in the total volume of body water May be isotonic, hypertonic, hypotonic
Renal Excretion
Increased by: -Aldosterone -Most diuretics except potassium-sparing -Influenced by extracellular pH -Alkalosis -Acidosis
Hypotonic contraction
Loss of sodium > loss of water Both volume and osmolality of ECF are reduced
ACE inhibitors
MOA: -Inhibits ACE -Reduced levels of angiotensin II --> dilate blood vessels, reduce blood volume -Increased levels of bradykinin ---> vasodilation; cough, angioedema Administration: -PO (most common) & IV -ALL are excreted by kidneys --> renal dosing PRN
Low pH Normal PaCO2 Low HCO3
Metabolic acidosis is characterized by:
High pH Normal PaCO2 High HCO3
Metabolic alkalosis is characterized by:
Potassium
Most abundant intracellular cation Reference range: 3.5-5.0mEq/L Extracellular concentrations are low Plays major role in: -Conducting nerve impulses -Maintaining electrical excitability of muscle -Regulating A/B balance
Furosemide (Lasix)
Most frequently prescribed loop diuretic Uses: Pulmonary edema Edematous states Hypertension (HTN) MOA: blocks reabsorption at ascending loop of Henle Rapid onset (PO 60 min; IV 5 min)
Triamterene
Non-aldosterone antagonist Uses: HTN Edema
alkaline
PaCO2 less than 35 is ___________
acidic
PaCO2 more than 45 is ___________
Hypomagnesemia
Prevention and treatment -Replacement: Magnesium oxide or sulfate (IM or IV) Adverse effects: -Neuromuscular blockade -Suppressed cardiac impulse conduction -Respiratory paralysis -Cardiac arrest
Kidneys
Primary regulator of potassium levels
Hyperkalemia
Principal complication of treating hypokalemia
Angiotensin-Converting Enzyme (ACE) Inhibitors
Prototype: Captopril
Angiotensin II Receptor Blockers (ARBs)
Prototype: Losartan (Cozaar®) Another example: Amlodipine (Norvasc®)
Steady-state control by ANS
Regulates AP by adjusting cardiac output (CO) and peripheral resistance
Low pH High PaCO2 Normal HCO3
Respiratory acidosis is characterized by:
High pH Low PaCO2 Normal HCO3
Respiratory alkalosis is characterized by:
Ramipril
Risk reduction of MI, stroke, and death in patients at high CV risk
Hyperkalemia
Serum potassium levels above 5.0 mEq/L
Hypokalemia
Serum potassium levels below 3.5 mEq/L
Thiazides
Similar to effects of loops Max diuresis is much lower than loops Depend on adequate kidney function: -Not effective when urine flow is scant -Can't be used with severe renal impairment -Ineffective if low GFR (<15-20 mL/min)
Frank-Starling Law
Stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction (the end diastolic volume), when all other factors remain constant.
ACE inhibitors
Suffix: -pril Indications: -HTN -HF -Acute MI -LV dysfunction -Diabetic and nondiabetic nephropathy Side effect: dry cough
Hypermagnesemia
Symptoms of mild intoxication: -Muscle weakness -Hypotension -Sedation -ECG changes Treatment: -Diuresis -IV Calcium gluconate -Dialysis
Heart Rate
The _______ ________ is controlled by the autonomic nervous system (ANS)
Furosemide (Lasix)
The following adverse effects are related to which diuretic: -Hypokalemia (dysrhythmias) -Hyponatremia, hypochloremia, and dehydration -Hypotension (loss of volume, relaxation of venous smooth muscle) -Ototoxicity -Hyperglycemia -Hyperuricemia
Furosemide (Lasix)
The following are drug interactions are for which diuretic: -K dependent drugs -Digoxin -Ototoxic drugs -Potassium-sparing diuretics -Lithium -Antihypertensive agents -NSAIDs
Hyperkalemia
Treatments of _______________ include: -Hold potassium-containing foods & salt substitutes -Hold potassium accumulating medications -Counteract potassium-induced cardiotoxicity
-Bicarbonate-carbonic acid buffer system -Respiratory system: CO2 (acid) -Kidneys: HCO3- (base)
What 3 systems help maintain acid-base disturbances?
-Hypovolemia (dehydrated) -Acid/Base imbalance -Electrolyte imbalances
What are some adverse effects of diuretics?
-Autonomic innervation -Fitness levels -Age -Hormones
What are some factors affecting heart rate?
-Heart size -Gender -Contractility -Duration of contraction
What are some factors affecting stroke volume?
-Systemic filling pressure -Auxiliary muscle pumps -Resistance to flow between peripheral vessels and the right atrium -Right atrial pressure
What are some factors that determine venous return?
-Bumetanide -Torsemide -Ethacrynic acid
What are some other high ceiling (loop) diuretics?
-Modest increase in diuresis -Substantial decrease in K+ excretion
What are some useful responses of potassium sparing diuretics?
-Cleansing -Balance -Excretion
What are the 3 basic functions of the kidneys?
-Filtration (happens in the glomerulus) -Reabsorption -Active tubular (secretion proximal convoluted tubule)
What are the 3 basic renal processes of the kidneys?
-Volume contraction -Volume expansion
What are the abnormal stages of hydration?
-Glomerulus -Proximal convoluted tubule -Loop of Henle -Distal convoluted tubule
What are the four functionally distinct regions of the kidney?
-Loop: Furosemide (Lasix) -Thiazide: Hydrochlorothiazide ("HCTZ") -Osmotic: Mannitol -Potassium-sparing: Aldosterone antagonists (Spironolactone) & Nonaldosterone antagonists (Triamterene)
What are the four major categories of diuretics?
22-26
What are the normal ranges for HCO3?
35-45
What are the normal ranges for PaCO2?
7.35-7.45
What are the normal ranges for pH?
-Aldosterone Antagonist (Spironolactone) -Non-Aldosterone Antagonist (Trimaterene)
What are the two subcategories of potassium sparing diuretics?
Carbonic Anhydrase Inhibitors
What diuretic is used for increased ocular pressure?
-Angiotensin-Converting Enzyme (ACE) Inhibitor (any with suffix "-pril") (Prototype: Captopril) Angiotensin II Receptor Blocker (ARB) Prototype: Losartan (Cozaar®) another example: Amlodipine (Norvasc®) -Direct Renin Inhibitor Prototype: Aliskiren -Aldosterone Antagonist Prototype: Eplerenone (Inspra ®)
What drugs act on the RAAS?
Block Na and Cl reabsorption
What is the MOA of diuretics?
3.5-5.0 mEq/L
What is the reference range of potassium? Note: ranges vary by facility and within the literature
Proximal tubule (greatest diuresis)
What is the site of action for diuretics?
Angiotensin II
Which angiotensin has the following actions: -Powerful Vasoconstrictor -Synthesis/Release of Aldosterone -Alteration of cardiac and vascular structure -Hypertrophy and remodeling in the heart -Thickening of blood vessels
ACE inhibitors
Which class of drugs contain the following adverse effects and black box warning? AE: -First dose hypotension (severe HTN, diuretic use, Na or volume depleted) -Cough -Angioedema (seek immediate care, never take again) -Hyperkalemia -Renal failure (renal artery stenosis, solitray kidney stenosis) **BBW** -Fetal toxicity -Fetal injury (2nd or 3rd trimesters)
ACE inhibitors
Which class of drugs have the following drug interactions? -Diuretics -Antihypertensive agents -Drugs that raise potassium levels -Lithium ---> lithium accumulation/toxicity -NSAIDs ---> reduced effect of ACEIs (advil, aleve, aspirin)
Hydrchlorothiazide (HCTZ)
Which diuretic has a MOA location of the early segment of the distal convoluted tubule, and peaks in 4-6 hours
Aldosterone Antagonist (Spironolactone)
Which diuretic has the following MOA: -Blocks aldosterone in distal nephron -Retains potassium -Increases excretion of sodium
Mannitol (Osmotic)
Which diuretic has the following MOA: Creates osmotic force in lumen of nephron --> diuresis
Non-Aldosterone Antagonist (Triamterene)
Which diuretic has the following MOA: -Disrupts Na-K exchange in distal nephron -Directly inhibits the exchange mechanism -Decreases sodium reuptake -Inhibits ion transport
Aldosterone Antagonist (Spironolactone)
Which diuretic has the following adverse effects and drug intercations AE: Hyperkalemia, Endocrine effect Drug Interactions: Thiazide and loop diuretics, Agents that raise potassium levels
Mannitol (Osmotic)
Which diuretic has the following adverse effects: -Edema -Headache -Nausea -Vomiting -Fluid and electrolyte imbalance
Non-Aldosterone Antagonist (Triamterene)
Which diuretic has the following adverse effects? -Hyperkalemia -Leg cramps -Nausea -Vomiting -Dizziness
Mannitol (Osmotic)
Which diuretic has the following uses: -Prophylaxis of renal failure -Reduction of intracranial pressure (ICP) -Reduction of intraocular pressure (IOP)
Potassium-Sparing Diuretics
Which diuretic is rarely used alone for therapy?
Mannitol (Osmotic)
Which diuretic must be given parenterally?
Severe Hypokalemia
Which form of Hypokalemia should be treated with the following: -IV potassium chloride (KCl) -If untreated, results in cardiac arrest -Must be diluted (40mEq or less) -Infused slowly (generally no faster than 10 mEq/hr) -Must never be administered by IV push
Mild Hypokalemia
Which form of Hypokalemia should be treated with the following: -PO potassium chloride (KCl) -Sustained-release version has fewer GI effects -Side effects: Abdominal discomfort, N/V/D -Should be taken with meals and/or full glass of H2O
d.) A patient who is prescribed a drug that promotes venous vasodilation (dizzy)
Which patient would the nurse expect to have the highest risk for postural hypotension? a.) A patient who is prescribed a drug that acts primarily on the arterioles b.) A patient who is prescribed a drug that blocks the renin-angiotensin-aldosterone system c.) A patient who is prescribed a drug that triggers the baroreceptor reflex d.) A patient who is prescribed a drug that promotes venous vasodilation (dizzy)
Volume contraction
decrease in total body water
acidic
pH less then 7.35 is _________
alkaline
pH more than 7.45 is ___________
Peripheral Resistance
regulated by constriction & dilation of arterioles (afterload)