Cardiac Anesthesia Flashcards
Types of Cardiac Surgical Procedures (5)
CABG Off pump (OP) CABG minimally invasive direct (MID) CABG valve replacement (can be done in cath lab/EP but we are talking about OR in this lecture) (congenital hearts fall here mostly) heart transplant
preoperative evaluation cardiac history assessment should include
severity of disease/hemodynamic status (cath/ECHO/EKG reports)
baseline EF, high LVEDP, pHTN, valvular and congenital lesions, CHF
dysrhythmia history
preoperative evaluation for cardiac surgeries: past surgical history specific for
past sternotomies (scarring around heart)
leg and groin vascular surgery
previous protamine use (yes if previous open heart)
preoperative evaluation for cardiac surgery: ask about angina presentation sx including
nausea, fatigue, DOE, SOB
preoperative evaluation for cardiac surgery: PMH should include (neuro)
TIA/CVA. look for carotid dopplers and ensure they are fixed if need be before open heart surgery
preoperative evaluation for cardiac surgery should include evaluation for these comorbid diseases
PVD DM HTN COPD renal disease (=prepare for postop care)
preoperative evaluation for cardiac surgery: ask about which kinds of meds?
anticoagulants
antianginals
insulin
ACEI’s
what questions should you ask about a previous cardiac catheterization
how many blockages
where they are
how blocked they are
if theres any collateral flow
what questions should you ask about the up to date echocardiogram
EF, valve function, wall abnormalities/diskenisia, calcified aorta, atrial thrombus (no CVA!)
what hematologic labs should be retrieved prior to cardiac surgery
PTT, PT, baseline ACT
clotting studies, especially platelet number and functionality (TEG)
T&C as well (and PRBC’s near OR)
what should you look for on a preop CXR for cardiac surgery
calcified aorta, cardiomegaly, edema
the following drugs should be continued through operative day for cardiac surgery (4)
antiarrhythmics
CCB’s
BB’s
nitrates
how do we decrease cardiac oxygen utilization during cardiac surgery
anesthesia, hypothermia, electrical silence/cardioplegia use, empty cardiac chambers, specifically LV (no LV distention!)
how to we maximize oxygen supply during cardiac surgery
maximize oxygen carrying capacity and flow. check for anemia, make sure PRBC’s are avail
hemodilution and acceptable perfusion and pressure and flow decreases viscosity and promotes flow
what does hypotension or hypertension result in during cardiac surgery
hypotension: decreased organ perfusion
hypertension: disrupts myocardial balance
name 3 myocardial protection strategies employed
cardioplegia induced asystole
hypothermia
hemodilution
how does cardioplegia induced asystole happen
electrical and mechanical activity ceases
potassium given continuously during cross clamping
must be able to cross clamp aorta: calcifications/clots already present?
blood versus clear prime (colloid versus crystalloid versus blood prime)
hyperkalemia is an issue with renal patients (and just an issue with this procedure in general)
how does hypothermia induced during cardiac surgery effect the patient
alters platelet function and reduces fibrin enzyme function
inhibits initiation of thrombin formation
reduced metabolic demands and increases tolerance to ischemia
CABG order of events
preoperative prep monitors lines induction wait incision drop lungs sternotomy surgical dissection (not super stimulating, getting heart ready for intervention) cannulation on bypass off bypass dry up: give protamine close chest to ICU
monitors to consider for cardiac procedures
pulse ox (hypothermia and vascular disease may prompt you to try finger, ear lobe, nose)
TEE (in place of swan)
EKG (leads V5/II and ST segment monitoring)
temperature (foley is best)
ABP and cuff (q minute induction pressure if no aline). usually radial, sometimes femoral
CVP: mandatory
PA catheter: for patients with severe LV dysfunction, patients with profound pHTN
BIS and NIRS: put on before induction for baseline
warmer under patient and fluid warmers
OGT in and out and then insert TEE
TEE helps diagnose underlying mechanisms ascribed to several scenarios including (8)
evaluation of ventricular filling (preload)
estimation of CO
assessment of ventricular systolic function
assessment of ventricular diastolic function
valvular pathology
calcified aorta (important for aorta cannulation)
cardiac tamponade
atrial thrombus
TEE helps to plan case interventions including
when to give volume when to start vasoactive drips re examine graft assessment of surgical repair may look for air with it. can move patient around to "de air" or may do needle aspiration
contraindications to TEE include
esophageal pathology (varices) empty stomach before placing probe
which 2 spots are you unable to see with a TEE
distal ascending aorta
proximal part of aortic arch