Positive Inotropes Flashcards
Cardiogenic shock
MI
Myocarditis
Arrhythmias
Valvular disease
CMP
Obstructive shock
Tamponade
Tension pneumo
PE
Distributive shock
Sepsis
Anaphylaxis
What does CHF respond to?
preload reduction
afterload reduction
Improved contraction
Low cardiac output syndrome (LCOS) causes
in patients coming off CPB
A combo of:
Inadequate DO2
Hemoilution
Hypocalcemia, hypomagnesemia
Kaliuresis
Tissue thermal gradients
Variable SVR
LCOS risk factors
DM
Old age
Female
Pre op decreased EF
Long duration CPB
LCOS patho & treatment
Stunned hypocontractile myocardium in response to ischemia and reperfusion
Positive inotropes
Increase DO2 (SvO2 >70%)
Increase VO2 (arterial lactate <2mmol/L)
cAMP dependent vs independent drugs
Beta agonists, dopaminergic agonists, PDE inhibitors
Cardiac glycosides
Calcium
Inodilator drugs and effects
Isoproterinol
Dobutamine
–
Increase HR
Increased AV conduction
Decreased SVR/PVR
Variable myocardial o2 consumption
Inoconstrictor drugs and effects
NE, Epi, Dopamine
Increased SVR
Increased O2 consumption
Increased HR
When not to use inodilators?
Tachyarrhythmias
When not to use levo/NE?
Low CO
this will decrease perfusion and cause renal failure
When not to use Dig?
Hypokalemia, renal failure, bradycardia, drug interactions
Arrhythmogenic potenital
1- isoproterinol
Epi
DA
Dobutamine
How does cAMP work in the heart
Drug bind Gs receptor on cell membrane
Gs actives adenylyl cyclase
Adenylyl cyclase converts ATP to cAMP
cAMP cause contraction via influx of CA from slow channels and causes ca sensitivity of CA regulatory proteins
cAMP broken down by PDDE3 to AMP
Levo doses
CO increases at low doses, but high doses increase afterload and cause reflex brady
EPI receptors per dose
low- B2 1-2mcg/min vasodilation decreases SVR, though map stays same from mild increase in CO
Medium- B1 4mcg/min increase HR , inotropy, automaticity (PVCs)
high- A1 >4mcg/min
Catecholamine complications
Tissue ischemia
increased myocardial consumption and work
Inrease cardiac arrhythmias
Enhance lipolysis and gluconeogenesis
Activate coagulation
Isoproterinol effects
B1 B2
Increase hr, inotropy
Decrease SVR and DBP
Increased CO and decreased map
Bronchodilator
Isoproterinol SE
Tachycardia
DBP hypotension
Increased O2 consumption
Arrhythmias
Dont use in pt with ischemic heart diseases
Indications for isoproterinol
3rd degree HB
Bronchospasm during anesthesia
Decrease PVR in PH
Torsades, short QT syndrome
Dobutamine
B1 B2 small A1
Not as strong as isoproterinol
No DA
Increases renal blood flow by increasing CO
Increases CO and HR
High doses may cause arrhythmias
Not useful in low SVR/low BP patients
Renal dose Dopamine
0.5-2mcg/kg/min
Increased RBF, GFR, NA secretion, urine out put, but NOT RENAL PROTECTIVE
How must dobutamine be prepared?
D5W not NS which will inactivate it
DA and glucose, oxygen
inhibits release of insulin, causing hyperglycemia
Blunts respiratory drive
PDE3 inhibitors effects
Stop the breakdown for cAMP
Increase CA influx
Increase sensitivity of contractile proteins to CA
Increased CO, although decreased SVR and PVR
PDE3 inhibitor drugs
Milrinone- no risk of thrombocytopenia, stronger than inamrinone, shorter half life, decreased dose in RF.
Inamrinone- increases SC and CI after CABG, more effective than DA, but equal to epi causes thrombocytopenia,
Glucagon effects
Increases CI, HR, BP, decreases SVR and LVEDP
When to use glucagon, SE
Cardiac failure caused by beta blockers
NV, hyperglycemia, increased PVR/ coronary perfusion
Dig class and effect
Cardiac glycoside
Positive inotrope
- chronotropy
- dromotropy
Dig MOA electrolytes
Block (slows) NAKATPase, which holds NA in and keeps K out
This reduced NA doesnt allow NA/C pump to work, keeping more CA inside cell
When to use dig
A fib RVR
HF
Often used with diuretic and ace inhibitor
Dig toxicity effects
> 3ng/ml
Hyperkalemia bc it cant go back into cell
Risk factors: hypokalemia, hypomagnesemia, hypoxemia, hypercalcemia, hypothyroid
DIG toxicity presentation
Anorexia, nv
PVC
Atrial tachy w block
V fib and death
2nd degree type 2 block
Dig toxicity treatment
K, Mag, O2
Phenytoin/lidocaine for arrhythmias
Atropine for low hr
BB for automaticity
pacing if HB
Digibind
binds to dig in dig toxicity
eliminated by kidneys
levels are useless for several days so dont check
Dig interactions
Amio
Verapamil
PPI
Reglan
many more
Giapreza effects / se
Vasoconstriction and aldosterone release
interaction with acei and arbs
se: DVT so give prophylaxis blood thinner
tachycardia, delirium, thrombocytopenia
Plan for low CO
Real 1st- optimize HR
1st- optimize preload
2nd- optimize afterload
3rd- optimize inotropy
Last- IABP, LVAD if low CO and ischemia persists
Dig normal sign
Swoop in QRS
Dig normal sign
Swoop in QRS
