Exam 3- Cardiac, diuretics, anticoagulants, thrombolytics Flashcards
Flow of blood through the heart and
systemic v pulmonary circuit
inferior/sup vena cava R atria tricuspid valve R ventricle pulm semilunar valve pulm trunk pulm arteries lungs
reoxygenated blood into heart via pulm veins L atria mitral valve L ventricle aortic semi-lunar valve aorta ascending aorta body
pulmonary circuit- pulmonary arteries to veins (lungs)
systemic circuit- aorta-vena cava (body)
electrical stim pathway of heart
top to bottom
SA node, AV, apex, Purkinje fibers, ventricles (contraction starts at bottom)
primary pacemaker of heart- signal from atria to ventricles
stimulated by bradycardia (sympathetic ns) function- depolarize sinoatrial node (in uppr prt right atrium)
transfer signal via AV
beta 2 v beta 1 receptors
beta 1- stimulate AV node= inc heart contractility
can contribute to vent remodeling w/ pt that have heart failure
beta 2- stimulate sympth nervous system= bronchodilation
L v R sided heart failure
L- blood backs into pulm system, hypertrophy/ overstretched L ventricle= dec SV= dec CO
“congestive heart faliure” s/s hypoxia and trouble breathing
R- blood backs into venous system= inc p pulm arteries= pulm edema, jugular venous distention, ascites
alpha 1 receptors
cause vasoconstriction and sm musc contraction
s/s heart failure
dec cardiac output= fatigue, exercise intol
FVO- crackles (L HR), pulm edema, inc rr, SOB, distress dec o2
(R HR)- distended jugular veins, periph edema
systolic v diastolic HF (b/ left sided)
systolic- dec contractility- hF w/ reduced ejection fraction
diastolic- shortened filling/relaxation time- HF w/ preserved ejection fraction
classification of HF- AHA stage v NYHA functional
aha- structural- A-D *need to know ejection fraction to test structural changes
A= high fisk but no structural changes of s/s
B-=structural changes, no s/s
C= structural changes w/ prior or current s/s
D= changes and s/s at rest- need specialized interventions
functional- s/s I-IV (based on pt ability to function, and complete ADL) I-asympt II-symptom w/ mod exertion III- sympt w/ minimal exertion IV- symtom at rest
heart failure def + causes
dec tissue perfusion
abnormal heart function
cause- CAD, HTN
cardiac output
hr x stroke vol min/mL amnt blood pumped/min normal 3-7 L/min dec heart rate or sv= dec co
stroke vol
mL/contraction x # beats/min
dec sv=dec co
contractility
(inotropy) strength of muscular contraction of the heart
dec contractility = dec co
inc contractility= inc sv=inc co *till a certain point (if too stretch myosin fibers have no leverage)
preload- def and causes of inc/dec
amnt stretching of ventricular cardiac musc before a contraction begins
dependant on vol fluid in ven
heart failure= inc preload
inc vol= inc preload= inc contractility (until certain point)
dec vol= dec preload= dec stroke vol= dec contractility= dec co
ideal is btw 8-12
causes dec= hemorr shock, dehydration= dec contact btw actin and myosin fibers (too srunched)
inc= fluid overload= dec contact of fibers
ejection fraction
percent of blood in LV leaving w/ e/ contraction
dec contractility= dec EJ
afterload
resistance against which LV has to work to push blood into arteries
factors- SVR (p in arteries) can inc w/ vasoconstriction
inc svr= inc afterload (P)
inc svr + additional V fluid from heart failure (preload) w small valve opening = inc p/workload= L ventricular remodeling
purpose of measuring bp
tells us lvl resistance
diastolic- resting state
systolic= CO
MAP= afterload
pathway of hf
dec EF- dec contractility- dec CO- inc sympathetic activation- stimulation of beta 1 recep. (vasoconstriction, fluid retention)- inc hr and contractility- alpha 1 recep activation (inc pvr and inc afterload P)- inc myocardial workload- dec co- dec renal perfusion- inc renin secretion- inc angiotensin 1- angiotensin 2 (vasoconstriction, fluid retention and inc bp) *also cardiotoxic at high lvls can cause v remodeling
fluid retention bc- inc aldosterone (na and h2o retention- further inc preload- L HF-pulm edema and R HF- peripheral edema)
natrietic peptides
stimulated by hypertrophy LV
anp/bnp- natural diuretic/vasodil
goals of pharmacologic therapy in hf
improve QOL and dec mortality/morbidity
by inc contractility
dec afterload, elevations in preload, ventricular remodeling, peripheral (R) and pulm edema (L)
classes meds to trt hf
ace inhib angiotensin recep neprilisyn inhib (ARNI) cardiac glycosides diuretics beta blockers
ace inhib- types, action and indications
lisinopril, enalapril, captopril, benazepril
action- dec conversion from ang 1 to ang2= dec preload and afterload
indications- hf, htn, dec mortality and morbidity after MI, prevn diab nephropathy (dec p and therefore damage of glomerular basement mem)
need to take if EF < 50% or s/s HF bc can dec prel, afterload and vent remodeling while improving EF
ace inhib- containdications, pharmacokin
coindiated- preg/lactation, hypersen (angioedema), renal impairment
pharmacokin- Po, duration 24h, 100% renal elimination
ace inhib- ae
hypotension (dec ang2= dec ability vasoconstrict)
watch after 1st dose! and espec if FVD (dehydration)
persistant dry cough- if block converting enzyme= inc bradykinin= inc dry cough
angioedema- inc risk as inc bradykinin (swelling of throat, feeling fullness, something stuck in throat)
hyperkalemia- flip btw na and K, dec ang 2= dec aldosterone= dec fluid retention= inc K 3.5-5 can result in vent tachy- cardiac dysrhyth
angiotensin II receptor blockers (ARBs)- types-action and indication
Valsartan, Losartan, Candesartan
block effects ang 2
so same effect as ace just different chemical process (not acutally inhibit converting enzyme so no inc bradykinin)
therefore no inc problems w/ dry cough and angioedema
angiotensin II receptor blockers (ARBs)- pharmacokin v ace i
valsartan- liver metab, majority excreted via feces
losartan- extensive liver metab, excreted by kid as active metab
candesartan- prodrug- excreted in urine and majority in feces
** more liver metab, less kidney excretion worry
relationship btw vasodil and afterload
and aldosterone and preload
inc vasodil= dec SVR= dec constriction= dec afterload (P)
dec aldosterone= dec fluid retention= dec preload
Angiotensin recept- Neprylisin inhib (ANRI)- type, action, indication
ARB (valsartan) combo w/ neprylisin inhib (sacubitril) Entresto
neprylisin enzyme inactivates natrietic peptides (respon diuretic/vasodil)
inhibiting enzyme will inc anp/bnp= inc diuresis= dec preload and vasodil= dec afterload
preferred med if not taking anything to control HF
if switching to this frm acei need to stop taking acei or arb for 36h or high risk for angioedema
trial- improved HR s/s, dec hospitalizations and reduced mortality
nursing considerations for acei, ARB and ANRI
monitor bp (hypotension), incl orthostatic changes
monitor angioedema (esp w/ acei or switching)
monitor bun, cr, K+
renal bc acei fully excreted via kidneys, risk for hyperkal in acei
pt education- change position slowly, avoid salt sub w/ acei (already high ris k for inc K due to dec aldosterone)
cardiac glycosides (Digoxin)- action, indication
trt a-fib and control hr
action- inc contractility by inc Ca into musc cells= stronger contraction and enhance parasympath ns (vagal influences)= dec onduction via AV node frm artrial to ven= dec hr aka “rate ventricular contracting”
cardiac glycosides (Digoxin)- containd, route, pharmacokin
contraind- av heart block (rhythm abnormality delays conduction thru AV) so adding digoxin can exacerbate block
WPW- abnorm conduction pathway otherthan AV, so if shut off main pathway can overstim alt pathways
hypokalemia
renal impairment, acute MI (inc contractility= inc o2 demand= ae of MI)
trt MI before admin
route- Po or IV
pharmacokin- unchanged by kid
cardiac glycosides (Digoxin)-ae and inc risk
ae- bradycardia**
n/v, anorexia, abdom discomfort earliest s/s
blurred vision, green/yellow aura (halo arnd lights)
inc risk w/-
hypokalemia (K and med compete for same cardiac cell recep so if K is depelted med has more room to be activated and therefore cause toxicity)
extremes in age (inc sensitivity)
use loading doses
give inc dose so drug reaches theraputic range faster but can overshoot this and cause toxicity)
hypoxia (inc contract= inc o2 demand)
impaired renal function
cardiac glycosides (Digoxin)- nursing considerations
monitor apical pulse 1 min- hold if <60
continuous EKG for IV admin
assess therapeutic effect (should hold hr and stop afib)
geriatric consdier (ink risk falls if bradycardia bc dec sv=dec co= dec perfusion= syncope)
monitor labs (cr, bun, gfr, K+)
pt ed- how assess own pulse
hold med if <60
s/s dig toxicity (GI, visual changes, bradycardia)
test for pt w/ possible digoxin toxicity
K, bun, cr, gfr labs
akg
continuous heart monitor
if comes back positive- dig lab lvl
hold med
k supplement
temporary pacemaker (external transcut or transvenous)
types diuretics
loop
thiazide
aldosterone antagonists
loop diuretics- types, moa, indication
bumetanide (Bumex) po oriv
furosemide (lasix) po/iv *can dev resistance
torsemide (Demadex) iv only
moa- act on ascending loop to dec na and h20 resorption= inc excretion
indications- edema, s/s HF (dec vol= dec P on vessles= dec afterload), renal dis, hepatic cirrhosis, HTN
loop diuretics- pharmacokin, ae
absorbed in GI tract
onset po- 1h, IV 5-10 min
ae- electrolyte depletion (K)
s/s- weakness, dizziness, leg crmps, vomiting, confusion, dysrthmias
need K replacement -always check!
Gi disturb- diarrh, anorexia, stomach pain/cramping
hypotension- hold if <100
ototoxicity w/ IV admin if push too fast!
impaired glucose tol (might need inc insulin)
FVD or s/s overdiuresis- dry muc mem, dec urine output
reflected in labs- dec blood vol= dec LV supply= dec preload= dec sv= dec co= dec kidney function
=inc Cr, BUN, gfr (rapid)
loop diuretics- interactions
digoxin- toxicity/ hypokalcemia
corticosteroids- hyperglycemia and hypokalemia
warfarin- inc anticoag effect
inc hypotension w/ o/ antihtn meds
aminoglycoside antib “gentamicin”- ototoxicity
thiazide diuretic- type, moa, indication
hydrochlorthiazide (HCTZ)
moa- block na and cl reabsorption in distal tubule
indications- htn,
edema-HF, renal dis, cirrhosis, corticosteroids, estrogen therapy
thiazide diuretic- pharmacokin and contraindications
pharm- po, excreted unchanged by kidneys
contraind- allergy to sulfonamides. impaired renal function, lactation, pregnancy (jaundice/thrombocytopenia)
thiazide diuretic- ae and interactions
ae- hypokalemia, hypotension, inc uric acid (gout), hyperglycemia, gi (n/v, constipation), hepatitis (liver inflamm), pancreatitis
interactions- inc hypotension w/ o/ anti htn
corticosteroids- hyperglycemia, inc excretion k (hypokalemia)
digoxin- toxicity and hypokalemia
*similar to loop diuretics
aldosterone antagonist- type, action, indication
K+ sparing (dec aldosterone = inc K)
“Spironolactone” (Aldactone)
action- inhib aldosterone dec h2o and na resorption, inc K
indication- excess fluid assoc w/ HF and hepatic cirrohsis
can inc survival in pt w/ mod-severe HF
aldosterone antagonist- ae and interactions/ contraindicated
ae- hyperkalemia, skin rash, gi disturb, dizziness, sex hormone abnormalities (menstrual and gynecomastia)
interactions- caution w/ acei (inc risk hyperkalemia)
anticoag inc risk bleeding
digoxin- med can inc dig accum= inc risk toxicity
general diuretic considerations and pt ed
admin in am and early evening- prevent falls admin iV slowly 20mg/mL po diur w/ food dec gi monitor bp, hold if <100 weigh daily, I&Os labs- cr, bun, gfr, K bg's fluid imbalance (excess or deficiet) pt ed- older women don't take cause can cause incontin K+ supplements and s/s hypokalemia low sodium diet (no salt sub w/aci bc risk hyperkalemia) postural hyptension