Cardiac anesthesia 1 Flashcards
1 in 3 American adults have
one or more types of CVD
These minorities have a higher mortality rate from CAD
African Americans & Hispanics
Evidence supports that female gender short term survival after CABG is
worse than male gender but 5 yr survival rate is better
CABG surgical procedures include
CABG off pump CABG minimally invasive direct (MID)-CABG valve replacement heart transplant
Preoperative evaluation includes evaluating
cardiac history past surgical history angina presentation dysrythmias past medical history co-morbid diseases medications
Describe the assessment of cardiac history for the preoperative evaluation.
severity of disease/hemodynamic status
-<4 mets- cause for concern
catheterization, ECHO, & EKG reports
-what is baseline disease: low EF, high LVEDP, pulmonary HTN, valvular & congenital lesions, CHF
Describe the assessment of past surgical history
past sternotomy (scarring around heart)
leg and groin vascular surgery
previous protamine use?
Describe the assessment of angina presentation.
nausea, fatigue, DOE, SOB
Frequent past medical history for patients undergoing CABG includes
TIA, CVA
Co-morbid diseases for patients undergoing CABG includes
PVD (carotid disease), DM, HTN, COPD, renal= prepare for postop care!
Preoperative evaluations of medications that patients take include
anticoagulants, antianginals, insulin, ACEI’s
Preoperative cardiac testing includes
cardiac catheterization report ECG Echo report hematologic studies CXR renal function liver function tests type & cross
Patients undergoing cardiac surgery must have
PRBCs available
Liver function tests are important because
CPB may hypo-perfuse liver
Patients with decreased renal function have
increased post-op mortality
Chest XRs can show
calcified aorta, cardiomegaly, and edema
Hematologic studies include
PTT, PT, baseline ACT
-clotting studies, especially platelet number & functionality (thromboelastogram:TEG)
Describe how anesthetist may use ECG & cardiac catheterization reports
cardiac cath- locate blockages
ECG: recent MI (intraop MIs= 50% mortality)
The echo report can show
EF, valve function, wall abnormalities, calcified aorta, atrial thrombus (No CVA!)
These drugs should be continued until the operative day:
antiarrhythmics
Ca+ channel blockers
beta blockers
nitrates
Cardiac anesthesia goals include
decrease cardiac oxygen utilization
maintain oxygen supply
anticoagulation
maintain BP in target range
Describe methods that may be used to decrease cardiac oxygen utilization.
anesthesia
hypothermia
electrical silence, cardioplegia use
empty cardiac chambers, specifically the LV: no LV distension!
Describe methods used to maintain the oxygen supply.
maximize oxygen carrying capacity & flow
hemodilution and acceptable perfusion pressure & flow
Describe the effects of hypotension and hypertension.
hypotension= decreased organ perfusion hypertension= disrupts myocardial balance
Myocardial protection strategies include
cardioplegia induced asystole
hypothermia
hemodilution
Hemodilution is not really a protection strategy but flow
increases due to decreased blood viscosity
Describe how hypothermia allows for myocardial protection
alters platelet function & reduces fibrin enzyme function
inhibits initiation of thrombin formation
reduces metabolic demands and increases tolerance to ischemia
Describe how cardioplegia induced asystole protects the heart.
electrical and mechanical activity ceases
potassium given continuously during cross clamping
must be able to cross clamp aorta: calcification/clots already present?
blood versus clear prime
hyperkalemia is an issue with renal patients
The order of events for CABG includes:
pre-op prep monitors lines induction wait incision drop lungs sternotomy surgical dissection cannulation on-bypass off bypass dry up: give protamine close chest to ICU
Monitors that should be used for CABG may include
pulse ox TEE EKG- leads V5 & II temperature ABP- usually radial, sometimes femoral CVP-mandatory for infusion of drugs PA catheter- pts with severe LV dysfunction, pts with profound pulmonary HTN
Transesophageal can be used to
help to plan case interventions
helps diagnose underlying mechanisms ascribed to several scenarios
A transesophageal echo helps plan case interventions including
when to give volume
start vasoactive drips
re-examine graft
assessment of surgical repair
A transesophageal echo can help diagnose the following mechanisms:
evaluation of ventricular filling (preload)
estimation of cardiac output
assessment of ventricular systolic function
assessment of ventricular diastolic function
valvular pathology
calcified aorta
cardiac tamponade
atrial thrombus
Contraindications to transesophageal echo includes
esophageal pathology (alcoholic varices) empty stomach before placing probe
The pulmonary artery catheter used to be the standard monitor for cardiac surgical patients but is being
used less due to risk and use of TEE
Pulmonary artery catheters are typically placed
in the right IJ (IJ is the most direct route)
There is no evidence to suggest that PA catheters
offer additional information and have inherent risk in ICU patients
You know when the SWAN enters the pulmonary artery when the waveform shows ______________ in the PA versus RV
an INCREASED diastolic pressure
Complications of PAC include
ventricular arrhythmias heart block (especially in patients with preexisting LBBB) pneumothorax unintended arterial puncture valve damage hematoma/thromboembolism vascular injury perforation of thorax leading to hemothorax PA rupture blood stream infection cardiac tamponade
A pneumothorax is most common with a ______ approach for insertion of a PA cath
subclavian approach
The most common acute injury for Swan catheters is
unintended arterial puncture
The most common life threatening complication of CV cannulation with a Swan catheter is
cardiac tamponade
Prior to bypass, it is suggested to keep the blood pressure ______ and the heart rates between_________
within 20% of baseline pressure
HR 40-80 depending on clinical situation prior to bypass
Describe the recommendations for aortic stenosis.
Preload: maintain
SVR: maintain
HR: 50-80 (NSR)
Describe the recommendations for aortic regurgitation.
preload: maintain
SVR: low
HR: 50-80 (NSR)
Describe the recommendations for mitral stenosis.
preload: maintain
SVR: maintain
HR: 50-80 (NSR)
Describe the recommendations for mitral regurgitation.
Preload: maintain
SVR: low
HR: 50-80 (NSR)
Cardiac OR set up includes:
usual airway equipment/machine check pacemaker drips- vary by institution heparin & coag. monitoring capability emergency drugs PRBC available in OR
Describe the most common drips utilized for cardiac OR set up:
NTG/NTP Epinephrine/norepinephrine phenylephrine/ephedrine dopamine/dobutamine as needed antiarrhythmics (esmolol, lidocaine, mag, amiodarone)
Describe why epinephrine is preferred over norepinephrine.
epinephrine provides greater inotropy & chronotropy via alpha agonist
Cardiac anesthetic drugs include:
inhalation agent fentanyl/sufentail versed propofol/etomidate/ketamine vecuronium/rocuronium/cisatricurium succinylcholine or rocuronium if RSI antibiotic: cefazolin, vancomycin, clindamycin anti-fibrinolytics magnesium insulin drip
Anti-fibrinolytics are used because during CPB, large amounts of circulating TPA are found and
increased postop bleeding due to inappropriate fibrinolysis
To be effective, anti-fibrinolytics must be
started before going on CPB
include: ACA & TXA
Fibrinolysis is diagnosed via
thromboelastogram (TEG)
