Exam 3 Cardiac Flashcards
What needs to be evaluated pre-operatively in patients having cardiac surgery?
cardiac history
past surgical history
angina presentation
dysrhythmias
past medical history
co-morbid diseases
medications
When asking a patient about their cardiac history, what is prevalent?
severity of disease/ hemodynamic status
catheterization, ECHO, ECG reports
what is the baseline disease? (low EF, LVEDP, pulmonary HTN, valvular & congenital lesions, CHF)
What preoperative testing needs to be completed prior to cardiac surgery?
cardiac catheterization (locate blockages)
ECG: recent MI
ECHO report (EF, valve function, wall abnormalities, calcified aorta, atrial thrombus (no CVA)
Hematologic studies (Pt, ptt, baseline ACT)– clotting studies, platelet # and functionality (TEG)
CXR: calcifed aorta, cardiomegaly
renal function: decreased function increases post op mortality
liver function test: CPB my hypo-perfuse liver
T/C
What medications need to be continued?
antiarrhythmics
calcium channel blockers
beta blockers
nitrates
What are the goals of cardiac anesthesia? (4)
decrease cardiac oxygen utilization
maintain oxygen supply
anticoagulation
maintain BP in target range
How do you decrease cardiac oxygen utilization?
anesthesia, hypothermia, electrical silence, cardioplegia use, empty cardiac chambers, specifically in the LV (avoid distention)
How do you maintain oxygen supply?
maximize oxygen carrying capacity and flow
Hemodilution is acceptable perfusion pressure and flow
Describe myocardial protection strategies
cardioplegia induced systole
hypothermia
hemodilution
What is cardioplegic induced systole
electrical and mechanical activity ceases
potassium given continuously during cross clamping
must be able to cross clamp aorta (calcifications/clots present?)
blood vs. clear prime
hyperkalemia is issue with renal patients
How does hypothermia protect the myocardium?
alters platelet function and reduces fibrin enzyme function
inhibits initation of thrombin formation
reduces metabolic demands and increases tolerance to ischemia
Describe hemodilution’s role in myocardial protection?
increases flow due to decreased blood viscosity
List the order of events for a CAGB (15)
pre-operative preparation
monitors
lines
induction
wait
incision
drop lungs
sternotomy
surgical dissection
cannulation
on-bypass
off bypass
dry- up: give protamine
close chest
ICU
What monitors are needed for cardiac surgery? (7)
pulse ox
TEE
ECG (leads 2 and 5)
temperature
ABP (usually radial, sometimes femoral)
CVP (mandatory for infusion of drugs)
PA catheter
When do patients require a PA catheter?
severe LV dysfunction
profound pulmonary HTN
What does a transesophageal echo assess? (8)
evaluation of ventricular filling, estimation of cardiac output, assessment of ventricular systolic and diastolic function, valvular pathology, cardiac tamponade, calcified aorta, atrial thrombus
What interventions can a TEE help guide?
volume administration
start vasoactive drips
re-examine graft
assessment of surgical repair
What are contraindications for a TEE?
esophageal pathology (Alcoholic varices)
empty stomach prior to placing tube
When do you know the swan catheter has entered the pulmonary artery?
the waveform shows an increase diastolic pressure in the PA vs the RV
What are complications of the PAC/Swan? (11)
ventricular arrhythmias
heart block
pneumothorax
unintended arterial punction
valve damage
hematoma/ thromboembolism
vascular injury
perforation of thorax leading to hemothorax
PA rupture
cardiac tamponade
BSI
What patients have an increased risk of heart block with a Swan catheter?
LBBB
What is the most common acute injury of a PA catheter?
unintended arterial puncture
When is a pneumothorax from a PA catheter placement most common?
subclavian approach
What are the goal pre-bypass hemodynamics?
BP between 20% of patient’s baseline
HR between 40-80 are generally fine depending on situation prior to bypass
What are hemodynamic goals pre-bypass for aortic stenosis?
maintain preload
maintain SVR
HR 50-80
NSR
What are the hemodynamic goals of pre-bypass for aortic regurgitation?
Forward, fast and full
maintain preload
Low SVR
HR 50-80
NSR
What are the hemodynamic goals of pre-bypass for mitral stenosis?
Maintain preload
maintain SVR
HR 50-80
NSR
What are the hemodynamic goals of pre-bypass for mitral regurgiation?
maintain preload
HR 50-80
NSR
low SVR
What is needed for OR set up in cardiac cases? (6)
airway/ equipment
pacemaker
drips (NTG/NTP, E/NE, Phenylephrine/epedrine, dopamine/dobutamine, antiarrhythmics- esmolol, labelotol, magnesium, amiodarone)
heparin and coagulation monitoring
emergency drugs
PRBCs
magnesium
insulin drip
antifibrinolytics
Pre-induction patient preparation (7)
Nasal Cannula
mild sedation
PIVs x2, arterial line
baseline ABG and baseline ACT
cross matched blood
placed external defibrillation pads prior to induction
make sure team is aware rolling back
When can propofol be safely used for induction?
patients with ischemic and valvular heart disease
Describe the use of ketamine during induction
CV effects are advantangous
Biggest challenge is CV stimulation
What needs to be avoided during induction and CPB?
N2O
Describe the effect of VAs during cardiac anesthesia (6)
produce dose dependent global cardiac depression
negative effects of volatile anesthetics are due to alterations in intracellular Ca++
sensitized myocardium to the effects of EPI in varying degrees
may prevent or faciliate atrial or ventricular arrhythmias during myocardial ischemia or infarction
produce weak coronary artery dilation and depresses baroreceptor reflex control of arterial pressure
How can you treat hypertension from incision?
deepen anesthetic, vasoactive agents (NTG, NTP)
Discuss events from incision to bypass (7)
intense surgical stimulation
hypertension
handling of heart by surgeon
bleeding can be significant
identifying and localizing ischemia
drop lungs for sternotomy
arterial and saphenous veins are harvested
What is the MOA of heparin?
binds to antithrombin 3 and potentiaes its natural anticoagulant properties
What is the dose of heparin prior to initating bypass?
300-400u/kg
wait 3-5 minutes for ACT
What is a normal ACT
<130seconds (80-120)
What is the goal ACT during CPB
400-450