PRIN 3 - Test 3 AnesCardSurg YSK Flashcards
What is the MAP range where autoregulation of Coronary perfusion pressures occur?
60-140 mmHg
What is the most useful measure of coronary perfusion?
MAP
In patients with CAD autoregulation ceases beyond a partial obstruction. In these patients what happens to coronary perfusion and at what MAP does this occur?
Coronary perfusion (flow) becomes pressure dependent; MAP < 70mmHg
When does most (80%) of the blood flow to the LV, during Diastole or Systole?
During this time, Is LVEDP high or low?
Diastole
Low
Decreasing HR has what effect on filling time and O2 demand?
Decrease HR, Increases filling time and Decrease O2 demand.
Subendocardial ischemia is associated with what EKG changes?
ST Segment depression
What is the effect of increasing HR on O2 demand and diastolic time?
INC HR causes INCrease O2 demand and a DECrease filling time.
Transmural (epicardial) injury causes what changes on the EKG?
ST elevation
What is the most significant cause of perioperative ischemia?
Elevated (High) HR
Intraoperative management of pts with CAD or an elevated LVEDP includes maintaining an adequate ______ and a low _______.
MAP; HR
What is the generally accepted target HR?
Less than 70 bpm
According to Laplace’s law, wall thickening ________ (increase or decreases) wall tension/stress, and chamber dilation _______ (increases or decreases) wall tension/stress?
Decreases;
Increases
What happens to the EF with Concentric Hypertrophy and Eccentric Hypertrophy?
Concentric - No change in EF
Eccentric - DECrease in EF
Pts with concentric hypertrophy have a thick LV that is caused by elevated?
LVEDP
Management of Pt with LVH are managed by maintaining a (higher/lower) MAP and a (higher/lower) HR?
Higher MAP
Lower HR
The compensatory response to LV volume overload is characterized by (3)?
LV volume overload causes
eccentric ventricular hypertrophy,
HF
DECreased EF
The pathophysiologic sequence of developing myocardial ischemia.
Ischemia cascade
Ischemia cascade
Myocardial O2 supply and demand imbalance –> Diastolic Dysfunction –> Systolic Dysfunction –> ECG changes –> Clinical symptoms –> MI, CHF, Shock
In the Ischemia cascade diastolic dysfunction leads to ventricular stiffening and decreased compliance which causes what type of (vessel) pressure change?
INCrease Pulmonary Artery End Diastolic Pressure (PAEDP)
What are the ischemia monitors?
TEE
ECG Leads V4, V3 and V5
A powerful biomarker for diagnosis, determination of severity, and prognostication of heart failure released primarily from the ventricles.
B-type natriuretic peptide (BNP)
Concentric LVH (Ventricular Remodeling - Thick) occurs in response to _________ and leads to ________ failure>
Pressure overload,
Diastolic
Eccentric LVH (Ventricular Remodeling - Dilatation) occurs in response to _________ and leads to ________ failure>
Volume overload
Systolic
Normal EF = %
Mild Systolic Dysfunction = %
Moderate Systolic Dysfunction = %
Severe = %
Normal EF = 55% or greater
Mild Systolic Dysfunction = 45-54%
Moderate Systolic Dysfunction = 35-44%
Severe = less than 30%
Causes of Systolic Dysfunction include?
CAD
Dilated cardiomyopathy
Chronic volume overload (MR, AR and high output failure)
Later stages of chronic pressure overload (AS and chronic HTN)
Demand Ischemia is caused by concentric or eccentric LVH?
Concentric LVH, INC in wall thickness and DEC in compliance.
When managing a patient with Concentric LVH the patients are prone to _________, thus the MAP must be keep _______ (high or low) and HR _______ (fast or slow)?
Ischemia
HIGH MAP
Slow normal HR (is CRUCIAL)
A pt with Concentric LVH what happens with regards to chest compressions during CPR
Chest compressions rarely generate enough pressure to perfuse the hypertrophied, noncompliant LV.
A type of RHF caused by pulmonary hypertension that causes systemic venous congestion, hepatomegaly and peripheral edema.
Cor Pulmonale
What is the goal in managing RHF?
Improve contractility and reduce right heart afterload.
Which inhaled anesthetics should be avoided with Right heart failure?
Desflurane and Nitrous
NYHA Functional Class I
Pt is Asymptomatic
NYHA Functional Class II
Pt has symptoms with MODERATE exertion
NYHA Functional Class III
Pt has symptoms with MINIMAL exertion.
NYHA Functional Class IV
Pt has symptoms with REST
Formula for BSA (meter squared)
BSA = Square root of [ (Ht cm x Wt kg) / 3600 ]
Formula or Cardiac Index (CI)
CI = CO/BSA
Normal range for CI =
2.8-4.2 L/min per m2
Four preop evaluation points for pt’s with implantable devices?
1) Interrogate device
2) Why is it in place
3) Presentation without device
4) Is it an AICD (use a magnet)
What is the benefits to using IA?
IA have a preconditioning effect and myocardial protective (in a dose dependent manner).
When fast-tracking patients after cardiac surgery, how soon should they extubated?
Within 6 hours
Anesthetic management of a patient undergoing cardiac surgery, What is the dose of fentanyl?
Sufentanil?
Fentanyl = 5-20 mcg/kg
Sufentanil = 2-10 mcg/kg
For older patients and patients with carotid disease to ensure adequate cerebral perfusion, what is the desirable MAP
MAP closer to 60 to 70 mm Hg
What is the standard heparin cardiac dose
Heparin 300-400 units/kg
Adequate anticoagulation is measured using what 2 tests?
ACT (activated clotting time)
Hepcon (Heparin concentrated assay)
ACT normal value =
ACT Before CPB is initiated =
How often after heparin is ACT measured?
Normal ACT = 80 - 120 sec
For CPB = 400 - 480 sec
Measure Every 3-5 mins
How often should anticoagulation be checked during bypass?
every 20 - 30 mins
Heparin Resistance is defined as…
ACT less than 480 secs despite admin 400-500 units/kg IV.
What is the Tx for Heparin Resistance?
d/t AT III deficiency…
2 units of FFP
AT III concentrate
recombinant AT III
Uses for TEE (10)
1) Find Aortic Cannulation site.
2) Diagnosing aortic atheroma and dissection
3) Detection of wall motion abnormalities.
4) R & L Systolic and Diastolic Ventricular function.
5) Pericardial effusion and tamponade
6) valvular area, function, and pathology
7) intravascular volume status
8) intracardiac air or pulmonary embolism
9) Evaluation for failed CPB separation
10) For Cardiac Tamponade - Monitoring ventricular function and guiding surgeon in removing trapped fluid.
What are the two approaches for cardioplegia
antegrade (thru coronary arteries) and retrograde (thru coronary sinus)
With the retrograde approach to myocardial preservation, when the catheter for cardioplegia is placed prior to CPB, manipulation of the heart can cause what two complications?
Dysrhythmias (AF) and hypotension.
Treat AF with Sync Cardioversion
Which myocardial preservation approach has cardio-protective effects when there is coronary obstruction?
Retrograde.
Bleeding and blood loss is of concern in high risk populations. What antifibrinolytic may be used, dose and admin time?
Aminocaproic acid (amicar)
50 mg/kg bolus over 20 to 30 minutes
Infusion 25mg/kg/hr.
What are two neuroprotective measures used for patients on CBP?
HINT: one is to prevent gaseous emboli.
1) hypothermia (proven efficacy)
2) CO2 operative field flooding
DM management in the preop period include….
Holding oral hypoglycemic for _____ (how long?)
How often are you checking glucose levels the day of surgery?
What is the target range (GOAL) for glucose?
24 hours
Q 30min - 1 hr (FREQUENTLY)
< 180 mg/dL
After open heart surgery, patient on the floor, what is the goal blood glucose levels after meals?
180 mg/dL or less
Indications for Pulmonary Artery Catheters (3)?
1) Frailty with multiple comorbidities
2) Left and Right Ventricular Dysfunction
3) PHTN
PAC are used to monitor?
1) Intracardiac ________
2) _____, using thermodilution
3) ________ (in the fancy catheters)
1) Intracardiac pressures
2) CO, using thermodilution
3) continuous mixed venous saturation.
What is a contraindication for Pulmonary Artery catheters?
Patients who have had pacemaker leads placed in the past 6 weeks because of the possibility of lead displacement
With PAC caution must be used in patients with what comorbidity and why?
Pt with LBBB because as catheter enters the RIGHT ventricular outflow track patients can develop RBBB.
This can lead to CHB!!
What is the formula for SV?
SV = CO x 1000/HR
Normally 50-110 ml per beat
Absolute Contraindications for TEE (5)
Strictures Diverticula Tumors Traumatic interruption Recent Suture Lines
In the perioperative period, when is a TEE done, what is it used for, how many views for a comprehensive and a targeted exams?
TEE before CBP to establish a baseline
Comprehensive = 20 views
Targeted = 11 views
When coming off pump, during the rewarming phase, a terminal warm reperfusion cardioplegia solution called a ________ is administered and the perfusionist lowers the pump flow temporarily as the surgeon removes the aortic cross-clamp.
HOTSHOT (warm cardioplegia)
On CBP - Rewarming or Cooling, What is the maximum allowable temperature gradient between the arterial outlet and venous inflow oxygenator
10 degrees celsius
During CBP Rewarming it is essential to avoid this thermodynamic state?
Hyperthermia can exacerbate damage in patients with cerebral ischemia or infarction.
What anticoagulation reversal agent is used? What is the test dose?
What is the therapeutic dose?
Protamine
10 mg
1 mg per 100 units of heparin administered over 10 - 15 mins (to avoid hypotension and anaphylactic reactions)
What pacemaker mode should the patient be placed on while the electrocautery is in use?
After?
Asynchronous (high risk for VF - d/t R-on-T)
Synchronous
What is Becks Triad and with what condition is it seen?
Low BP
JVD
Distant heart sounds
Cardiac Tamponade
Fluid in the pericardial sac causes myocardial compression in Cardiac Tamponade, this causes (several things) to occur:
Limits Diastolic filling time
Reduction in SV and CO
LOW SV and CO can result in:
- severe hypotension
- myocardial ischemia
- cardiac arrest
The TREATMENT for CARDIAC TAMPONADE include?
Percardiocentesis
Subxiphoid drainage
Mediastinal exploration
ASAP to prevent cardiac collapse.
For cardiac tamponade Tx what is used to optimize preload prior to pericardiocentesis?
Crystalloid, colloids and/or blood.
What happens when cardiac tamponade is relieved?
Hypertension and tachycardia from endogenous catecholamine release should be anticipated by the anesthetist and treated accordingly.
Off-Pump CABG is reserved for?
Patients with good LV function
For Off-pump CABG how is the heart protected during distal anastomosis?
CPP is maintained by keeping high MAP
90 - 100 mmHG during distal anastomosis.
For Off-pump CABG what are the parameters for partially and fully heparinized anticoagulation?
Partially heparinize (100– 200 units/kg with an intended ACT of more than 300 seconds) Fully heparinize (300–400 units/kg with an intended ACT of more than 400 or 480 seconds)
