Term
| What is the most common cause of CAD? |
|
Definition
|
|
Term
| How is the prognosis of CAD determined? |
|
Definition
By 3 Factors:
1) The number of vessels involved
2) Which specific vessels are diseased
-Obstruction of left main (which branches to LAD and circumflex) is dangerous since it supplies LV
3) The degree of narrowing
-75% obstruction is significant |
|
|
Term
| What are the treatments for coronary arteriosclerosis? |
|
Definition
1) Drugs
-Nitrates, CCB, BB, ACEI, Statins, Anti-Coags
2) Percutaneous Coronary Intervention (PCI)
-Rotational Arthrectomy
-Balloon Angioplasty
-Stenting
3) Coronary Artery Bypass Grafting (CABG)
-Traditional Open Heart
-Minimally Invasive:
a. Off pump CAB
b. Minimally invasive CAB (MidCab)
c. Heart Port
d. Robot assisted CABG |
|
|
Term
| What are some risk factors that increase adverse outcomes of cardiac surgery? |
|
Definition
-Age
-Female gender
-LV function
-Body habitus
-Reoperation (“Re-do”)
-Type of Surgery
-Urgency of Surgery |
|
|
Term
| What are some common methods for calculating cardiac risk? |
|
Definition
-Cardiac anesthesia risk evaluation score
-Euroscore |
|
|
Term
| What is the rating for the Cardiac Anesthesia Risk Evaluation Score? |
|
Definition
1 - Pt with stable cardiac disease and no other medical problem. A noncomplex surgery.
2 - Pt with stable cardiac disease and one or more controlled medical problems. A noncomplex surgery.
3 - Pt with any uncontrolled medical problem or a pt having a complex surgery.
4 - Pt with any uncontrolled medical problem and a pt having a complex surgery.
5 - Pt with a chronic or advanced cardiac deasese for whom cardiac surgery is undertaken as a last hope to save or improve life.
E - Emergency: surgery as soon as diagnosis is made and OR is available. |
|
|
Term
|
Definition
| European System for Cardiac Operative Risk Evaluation a method of calculating predicted operative mortality for patients undergoing cardiac surgery. |
|
|
Term
| Describe the left main coronary artery. |
|
Definition
-Travels anteriorly, inferiorly and leftward from the ascending aorta; emerges from behind the pulmonary trunk
-Divides into the left anterior descending (LAD), the left circumflex, and sometimes a diagonal branches |
|
|
Term
| Describe the Left Anterior Descending Coronary Artery. |
|
Definition
A continuation of the left main coronary artery
Provides blood flow to:
-anterior 2/3rd of the the interventricular septum
-the right and left bundle branches
-the anterior and posterior papillary muscles of the mitral valve
-the anterior lateral and apical walls of the left ventricle
-collateral circulation to the anterior wall of the right ventricle |
|
|
Term
| Describe the left Circumflex artery. |
|
Definition
-Arises from the left main coronary artery
-Supplies blood to the left atrial wall, the posterior and lateral left ventricle, the
anterolateral papillary muscle, the AV node (10% of population) and the SA node (40- 45% of population). |
|
|
Term
| Describe the right coronary artery. |
|
Definition
| Supplies blood to the SA and AV nodes, the right atrium and right ventricle, the posterior 1/3rd of the interventricular septum, the posterior fascicle of the left bundle branch, and the interatrial septum |
|
|
Term
| What is cardiac contractility? |
|
Definition
| Myocardial contractility represents the intrinsic ability of the heart/myocardium to contract. Changes in the ability to produce force during contraction result from incremental degrees of binding between myosin (thick) and actin (thin) filaments. The degree of binding that occurs depends on concentration of calcium ions in the cell. |
|
|
Term
|
Definition
preload is the end diastolic pressure that stretches the right or left ventricle of the heart to its greatest geometric dimensions under variable physiologic demand.
In other words, it is the initial stretching of the cardiomyocytes prior to contraction. |
|
|
Term
|
Definition
Afterload is the tension or stress developed in the wall of the left ventricle during ejection.
In other words, it is the end load against which the heart contracts to eject blood. |
|
|
Term
|
Definition
| stroke volume (SV) is the volume of blood pumped from one ventricle of the heart with each beat. |
|
|
Term
| What is ejection fraction? |
|
Definition
Ejection fraction (EF) is the percentage of blood in the left and right ventricles pumped out with each heartbeat.
Normal is 55-70 |
|
|
Term
|
Definition
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in one minute.
Normal value: 4-8 |
|
|
Term
|
Definition
Relates the cardiac output (CO) from left ventricle in one minute to body surface area (BSA), thus relating heart performance to the size of the individual.
Normal value: 2.5-4 |
|
|
Term
| What is systemic vascular resistance (SVR)? |
|
Definition
| The resistance offered by the peripheral circulation to flow that must be overcome to push blood through the circulatory system. |
|
|
Term
|
Definition
Central venous pressure.
It is a good approximation of right atrial pressure, which is a major determinant of right ventricular end diastolic volume.
Normal Value: 0-8 |
|
|
Term
|
Definition
The pulmonary artery pressure (PA pressure) is a measure of the blood pressure found in the pulmonary artery.
Normal values: 25/10. Mean: 10-20 |
|
|
Term
|
Definition
Pulmonary capillary wedge pressure (PCWP) provides an indirect estimate of left atrial pressure (LAP).
Normal value: 6-12mmHg |
|
|
Term
| What percentage of CO does the myocardium receive? |
|
Definition
4-7%
225-250 mL/min
0.6-0.9 mL/g/min |
|
|
Term
| What is normal myocardial O2 consumption? |
|
Definition
65-70% extraction
8-10 mL O2/100g/min |
|
|
Term
| What is the normal autoregulation range? |
|
Definition
|
|
Term
| How much coronary filling happens during diastole? |
|
Definition
|
|
Term
| What factors contribute to supplying O2 to the heart? |
|
Definition
1) Coronary artery anatomy
2) Diastolic pressure
3) Diastolic time
4) O2 extraction
-Hgb
-SaO2 |
|
|
Term
| What factors contribute to O2 demand of the heart? |
|
Definition
1) Heart rate
2) Preload
3) Afterload
4) Contractility |
|
|
Term
|
Definition
-Inotrope
-Rate: 1-20 mCg/kg/min
-Alpha and Beta adrenergic
Onset: 2-4 min
DOA: 10-20 min |
|
|
Term
|
Definition
-Increases Nitric Oxide = vasodilation
-Decreases preload (more) & afterload
Dose: 5-200mCg/min
Onset: 1-2 min
DOA: 3-5 min |
|
|
Term
|
Definition
-Smooth muscle relaxation = veno/arterial dilation
-Decrease afterload (more) & preload
Dose: 0.5-10mCg/kg/min
Onset: Immediate
DOA: 1-10 min |
|
|
Term
|
Definition
-Sympathomimetic, vasopressor
-Direct alpha and beta stimulation
Dose: 1-10mcg/min (lower dose- more alpha, higher dose- more beta)
Onset: <1min
DOA: 10 min |
|
|
Term
|
Definition
-Inotrope & chronotrope
-Beta-1 stimulator
Dose: 2.5-20 mCg/kg/min
Onset: 1-2 min
DOA: 10-15 min |
|
|
Term
|
Definition
-Sympathomimetic
-Alpha and Beta agonist
-Inotrope
Dose: 2-20 mCg/min
Onset: 1-3 min
DOA: 5-10 min |
|
|
Term
|
Definition
Primacore
-Inotrope
-Vasodilator
-PDE 3 inhibitor
Dose (bolus): 50mcg/kg over 10 min
Dose (gtt): 0.375-0.75mcg/kg/min |
|
|
Term
|
Definition
Pressor
-Vasoconstriction
-Increases H20 reabsoroption
Dose: 0.01-0.05 units/min
Onset:1-3 min
DOA: 10-35 min |
|
|
Term
|
Definition
-Beta blocker
-Selective Alpha, non-selective Beta blocker
Dose: 5-20mg
Onset: 1-5 min
DOA: 2-4 hours |
|
|
Term
|
Definition
-Selective B blocker
Dose (bolus): 500mcg/kg over 1 min
Dose (gtt): 50-300mcg/kg/min
Onset:2-10
DOA:10-30 |
|
|
Term
|
Definition
-Stabilizes cell membrane
-Increases contractility (Inotrope)
Dose: 200-1000mg IV slowly
Onset:1-5 min
DOA: 10-30min |
|
|
Term
|
Definition
-Antiarrhythmic
-Blocks Na channels
Onset: 1 min
DOA: 10-20min |
|
|
Term
|
Definition
-Inhibits Alpha & Beta stimulation
-AV & Sinus node decrease
Dose: 150/300mg
Onset: 1-15 min
DOA: 1-3 hours |
|
|
Term
|
Definition
-Slows SA node impulse
-Decreases Ach release @ motor end plate
Dose: 1-2 gm
Onset:
DOA: |
|
|
Term
|
Definition
-Calcium channel blocker
-Slows AV conduction and prolongs PR interval
Dose: 2.5-10mg |
|
|
Term
|
Definition
-ANticoagulant
-Binds to anti-thrombin 3
Dose: 300-400 units/kg
Target ACT >400 sec |
|
|
Term
|
Definition
-Heparin Antagonist
-Strong base (heparin is acid)
Dose: 1mg/100units heparin
Caution:
-Give over 1 min
-Fish allergy
-NPH insulin patients
-Vasectomy |
|
|
Term
|
Definition
-Aminocaproic Acid
-Antifibrinolytic (clot stabilizer)
-Amicar is a synthetic analog of lysine. It is used in cardiac surgery to prevent fibrinolysis.
-Occupys binding sites on the plasminogen molecule thus preventing the interaction of plasminogen with fibrin.
-If using, have 2 bottles available (5G each).
Dose: 5gm pre/post bypass slowly |
|
|
Term
|
Definition
|
|
Term
| What are we worried about with left main stenosis? |
|
Definition
| -If >70%, may be sensitive to HoTN or tachycardia |
|
|
Term
|
Definition
-Indicator of poor prognosis
-LAD, circumflex, and RCA involvement
-Left Main stenosis is worse |
|
|
Term
| Are we worried about vessels others than the LAD, circumflex, or RCA with heart patients? |
|
Definition
-Not as predictive for anesthetic difficulty
-Unless there is "poor runoff"
:that may make surgical revascularization difficult |
|
|
Term
| What are the associated risk levels and EF? |
|
Definition
EF >50% = low risk
EF 25-50% = Intermediate risk
EF <25% = high risk |
|
|
Term
| What should we look for on an EKG before cardiac surgery? |
|
Definition
-Q-waves: might mean ischemia and reduced function
-ST changes: ischemia
-LBBB: Risk for complete HB during SG float |
|
|
Term
| What would be negative indicators on a chest X-ray prior to cardiac surgery? |
|
Definition
-Cardiomegaly
-Pleural effusions
-CHF |
|
|
Term
| Why do we assess neuro function prior to cardiac surgery? |
|
Definition
| CPB can cause stroke or "pump head" |
|
|
Term
| What is important to note for DM patients prior to cardiac surgery? |
|
Definition
-BS can rise during cardiac surgery even if the patient isn't diabetic.
From: Impaired endothelial function, cardioplegia, surgical stress.
-Patients on NPH can have an allergic reaction to protamine
Pretreat with: Antihistamines, steroids, H2 blockers |
|
|
Term
| What is important to note about renal function prior to cardiac surgery? |
|
Definition
Longer CPB can worsen renal function.
Preop labs should include kidney function |
|
|
Term
| What labs should be done prior to cardiac surgery? |
|
Definition
-CBC
-Coags (pt, ptt, INR)
-Lytes
-BS
-Renal function
-Cardiac enzymes, BNP |
|
|
Term
| What needs to be assessed for patients who are on anticoagulants prior to cardiac surgery? |
|
Definition
If they are on antiplatelet drugs they may have increased bleeding.
-May need PLTs
-Plavix pts may require steroids intra/post op
-Aspirin is continued
Heparin
-Usually DC'd 4 hours preoperatively
-If critical, may be continued into OR |
|
|
Term
| What drugs should be drawn up prior to cardiac surgery? |
|
Definition
-Fentanyl 20cc
-Vecuronium: 10mg
-Anectine (drawn up and available)
-Versed: 5- 10mg (aim for less for fast tracking)
-Diprivan or Etomidate: as needed The use of Diprivan, or
Etomidate will reduce the amounts of narcotics and benzodiazepines used and may therefore expedite awakening in ICU.
-Neosynephrine syringe 10ml of 100mcg/ml
-Epinephrine syringe 1 mg (1:10,000 in box)- available on table top
-Nitroglycerine 10 ml syringe (check with the CRNA)
-Bactoban (mupirocin) ointment
-MgSo4 2g (but make sure that more is available)
-CaCl- 1g (but make sure that more is available)
-Lidocaine 100mg
-Amicar 5g- two syringes
-Amiodorone |
|
|
Term
| What equipment should be in the room prior to cardiac surgery? |
|
Definition
-Pacemaker with new batteries
-TEE
-Pumps
-Warming devices |
|
|
Term
| What type of case would necessitate blood being in the room? |
|
Definition
A redo because of the sternotomy.
-2-4 units PRBCs
-10 units of PLTs if on Plavix |
|
|
Term
| Where on the table should the patient be positioned for cardiac surgery? |
|
Definition
| The patient positioned so that shoulders are just below the crack in the OR table at the headrest. |
|
|
Term
| What side should the A-line go in for cardiac surgery? |
|
Definition
|
|
Term
| What position should the patient be in for PA catheter insertion? |
|
Definition
-Trendelenberg for insertion of PA sheath
-Reverse Trendelenberg with left rotation for floating of the PA catheter. |
|
|
Term
| What do you do if significant PVCs occur during PA insertion? |
|
Definition
| -Stop trying to get the catheter to wedge and settle for just getting into the pulmonary artery. |
|
|
Term
| What can happen to a patient with aortic stenosis during PA catheter insertion? |
|
Definition
-PVCs during central line placement can result in lethal arrhythmias that do not respond to defibrillation due to dilation of the atria.
-Consider giving Lidocaine prior to guide wire insertion and/or catheter insertion. |
|
|
Term
| After lines are inserted, what should you do? |
|
Definition
Get baseline readings:
-CO, CI, CVP, ST segment, etc
Connect drips to manifold. |
|
|
Term
| What drugs are usually run as drips during cardiac surgery? |
|
Definition
-Nitroglycerin 50mg/250 .9 NS (200 ug/cc)—now a “stick” -Vasopressin
-Epinephrine 2 mg in 250cc .9 NS (8ug/cc)
-Norepinephrine 8 mg/250cc .9 BS (64 ug/cc)
-Insulin 100 units/100 ml .9NS (infused per protocol) |
|
|
Term
| What is the BS goal during cardiac surgery? |
|
Definition
|
|
Term
| What CI must be reached prior to rewarming? |
|
Definition
|
|
Term
| What things in a patient's history classify them as having poor LV function? |
|
Definition
-multiple MI’s
-symptoms of CHF
-EF < 0.40
-LVEDP > 18 mm Hg
-multiple areas of ventricular dyskinesia
-decreased cardiac output |
|
|
Term
| What type of induction is needed for a patient with poor LV function? |
|
Definition
-light preoperative sedation
-narcotic technique, won’t be fast tracked if severe disease |
|
|
Term
| How might a patient with good LV function present for cardiac surgery? |
|
Definition
History:
-angina
-HTN
-no symptoms of CHF
Cardiac Catherization
-EF > 0.50
-LVEDP < 12 mm Hg
-no areas of ventricular dyskinesia
-normal cardiac output |
|
|
Term
| What would induction look like for a patient with good LV function presenting for cardiac surgery? |
|
Definition
-heavy premedication
-IV sedative for insertion of monitoring catheters
-blunting of sympathetic
-potent inhalation agents |
|
|
Term
| Do you use an OGT for cardiac surgery? |
|
Definition
Yes. Insert to decompress the stomach, them remove it prior to TEE insertion.
It is reinserted after the TEE is removed at the end of the case. |
|
|
Term
| What is a TEE helpful in detecting? |
|
Definition
1) regional and global ventricular abnormalities,
2) chamber dimensions,
3) valvular anatomy
4) intracardiac air. |
|
|
Term
| What should be checked after induction during cardiac surgery? |
|
Definition
| CO (along with all the other normal stuff) |
|
|
Term
| What medications should be given prior to sternotomy? |
|
Definition
-MgSO4 2g in burretrol
-Amicar 5g prior to sternotomy in burretrol
-Bactoban intranasally (Antibiotic for prevention of staph infections) |
|
|
Term
| What lab should be drawn prior to giving Amicar? |
|
Definition
| ACT Activated Clotting Time |
|
|
Term
| What is the only drug that must given prior to CPB? |
|
Definition
Heparin
-Dose is Generally .3cc/kg (300 unit/kg).
-Must be readily available in case CPB is initiated emergently. |
|
|
Term
| What lab must be drawn prior to heparinization? |
|
Definition
-The TEG (Thromboelastograph) is a device which can help determine a patient’s coagulation status.
- The results can diagnose whether the patient is deficient in one type of blood component, or if the heparin is fully reversed.
-Evaluates clot formation and dissolution
-Integrity of the coagulation cascade
-Platelet function
-Platelet-fibrin interactions
-Fibrinolysis |
|
|
Term
| What is the "prep area" for cardiac surgery? |
|
Definition
-Sternum to toes
-Secure OET prior to this to avoid field contamination |
|
|
Term
| What happens to preload during leg positioning? |
|
Definition
The legs will be:
-raised (increasing preload)
-lowered (decreasing preload) |
|
|
Term
| What vessel is most commonly used for harvesting during CABG and why? |
|
Definition
-The saphenous vein
-can be used because of the body's dual venous system which allows a deep venous system to take over the task of conveying blood to the heart after the saphenous vein is gone. |
|
|
Term
| What is given prior to vein harvesting? |
|
Definition
-5,000 units of Heparin during vein preparation.
-This is deducted from the total calculated dose of Heparin.
-CRNA: Administer the 5000 units of heparin and confirm verbally prior to giving. |
|
|
Term
| What are the highest levels of stimulation during cardiac surgery? |
|
Definition
o Induction
o Incison
o Sternal split
o Sternal spread. A very high level of stimulation.
o Aortic cannulation |
|
|
Term
| What should be done with the vent just prior to sternotomy? |
|
Definition
-Lungs down during sternotomy—listen for the saw
-Confirm reinflation of both lungs after the chest is open |
|
|
Term
| What gas mix should be used during cardiac surgery? |
|
Definition
-Oxygen with high fiO2s.
-May add air which will assist in preventing absorption atelectasis.
-Adjust according to ABGs.
-N2O may be used prior to cannulation in stable patients but is rarely done |
|
|
Term
| What is the CPB primed with? |
|
Definition
-plasmalyte
After priming is complete, drugs are added to the prime;
-10 ku Heparin,
-50 meq Bicarbonate,
-12.5 g Mannitol and
-occasionally PBRCs and albumin (dependent upon surgeon determination.) If the Hct is <30 and the pt is very sick, then rbcs may be used to prime the CPB machine. Hct can be expected to drop 8-10 on CPB. |
|
|
Term
| What vessel is dissected from the chest wall? |
|
Definition
| -left internal mammary artery |
|
|
Term
| What are the placements of the cannulas for CABG? |
|
Definition
-Aortic,
-Venous,
-Retrograde,
-blower,
-vein cannula,
-IMA cannula and a
-cardioplegia delivery line |
|
|
Term
| How might the table be positioned during IMA dissection? |
|
Definition
| The table should be tilted away from the surgeon and raised to allow optimal visualization for the surgeon during mammary dissection. |
|
|
Term
| Why might a left side radial A-line not function during cardiac surgery? |
|
Definition
| Left sided a-line may not function due to compression of the left subclavian artery. |
|
|
Term
| How much stimulation is there during the IMA dissection? |
|
Definition
-Very low
-May have to treat HoTN |
|
|
Term
| What should be monitored closely during endoscopic vein harvesting? |
|
Definition
|
|
Term
| What chamber of the heart is most visible during an open heart? |
|
Definition
-The RV
-You may be able to tell volume status by visual observation |
|
|
Term
| What happens to an EKG during sternal retraction? |
|
Definition
-EKG changes with chest wide open secondary to shifting V5 leads to a more lateral position.
-Voltage also may decrease as the heart is free of contact with surrounding conductive tissue. |
|
|
Term
| What FiO2 should the patient be on during sternal retraction? |
|
Definition
|
|
Term
|
Definition
-28g chest tube is inserted
-A pericardial sling is created |
|
|
Term
| What happens during a pericardial sling? |
|
Definition
| The sling may lift the heart which may decrease venous return causing HoTN |
|
|
Term
| When is the full heparin dose given? |
|
Definition
After:
- the leg vein is out
- the cannulation stitches/aortic pursestrings are applied
-Prior to cannulation. |
|
|
Term
|
Definition
1) Aorta
2) Retrograde cardioplegia line
3) Venous
4) Anterograde cardioplegia line |
|
|
Term
| Why/where is the aorta cannulated? |
|
Definition
-Arterial cannulation is for the delivery of oxygenated blood to the patient
-Usually performed through the ascending aorta, although the femoral artery and transverse arch can be used. |
|
|
Term
| What should the CRNA be aware of during aortic cannulation? |
|
Definition
• Possible blood loss- can replace volume via the aortic infusion line
• Check aortic clamp if partial occlusion is used, assess for drastic increase in afterload
• Before attaching the arterial pump line, the cannula must be tested for free blood return
• Inspect arterial line for air bubbles |
|
|
Term
| What is the purpose of venous cannulation? |
|
Definition
-The venous cannula drains the SVC and IVC.
-Venous cannulation involves manipulation of the right atrium. Can use single, two-stage cannula (a single that is inserted into the IVC and drains IVC from the end holes and the RA from fenestrations in the tubing 5 cm proximal to the tip) or separate SVC and IVC cannulae (require more manipulation). |
|
|
Term
| What should the CRNA be aware of during venous cannulation? |
|
Definition
• For patients who are dependent on atrial contraction for CO or patients with AF, should cannulate the aorta prior to handling the atrium at all
• Atrial arrhythmias (usually PAC’s or AF)
• Patients with CAD may be sensitive to atrial manipulation and can become hypotensive. Treatment – volume replacement |
|
|
Term
| Where is CVP checked after venous cannulation? |
|
Definition
- CVP is measured above the cannula, not from the right atrial portion of the PA catheter.
- CVP should be checked after cannulation and the face should be inspected for plethora to rule out SVC obstruction. |
|
|
Term
|
Definition
-Retrograde autologous prime is when the perfusionist draws off blood (about 500ml) from the arterial and/ or venous lines in order to replace crystalloid prime with the patient’s own blood and reduce the initial prime of the circuit.
-This is heparinized blood. Some patients require a small amount of pressor in order to do this, not volume. |
|
|
Term
| What should aortic cannulation produce? |
|
Definition
| -A pulsatile pressure that correlates with the radial MAP |
|
|
Term
| What could happen if the aortic cannulation is placed in a false lumen? |
|
Definition
| could result in a dissection of the aorta. |
|
|
Term
| What happens if ACT levels are resistant to heparin? |
|
Definition
| Thrombate (ATIII concentrate) or 2u FFP will be administered and the rechecking of the ACT. |
|
|
Term
| What is the perfusionists checklist prior to CPB? |
|
Definition
o Arterial cannula is in the aorta and demonstrated pulsatile flow via waveform correlating with radial arterial line.
o All gas bubbles are expelled from tubing
o All safety alarms and automatic shut-down sensors are functional and engaged
o All tubings are unclamped
o Oxygen is being supplied to the oxygenator
o Line pressures and flows are adequate for support of the patient |
|
|
Term
| What type of flow does the CPB generate? |
|
Definition
|
|
Term
|
Definition
| CP is cold perfusate containing blood and crystalloid. |
|
|
Term
| Where does cardioplegia enter the heart? |
|
Definition
-When given antegrade = forward (located between the xclamp and the aortic valve) it enters the aorta
-When given retrograde = backwards enters via the coronary sinus. |
|
|
Term
| When is cardioplegia given? |
|
Definition
-Cardioplegia is administered after the aortic cross clamp is applied.
-The heart and lungs are not stopped until “on bypass” is confirmed. |
|
|
Term
|
Definition
Cardioplegia crystalloid contains:
-potassium,
-magnesium,
-sodium,
-glucose,
-bicarb, and
-lidocaine.
-High dose contains 120 mEq KCl,- Low dose contains 60 mEq KCl |
|
|
Term
| What is "pinching" during CPB? |
|
Definition
- venous line is partially manually occluded to fill heart to measure grafts.
-Anesthesia may inflate the lungs at this time to assist with measuring and also for deairing. |
|
|
Term
| After CPB is initiated, what part of the procedure happens next? |
|
Definition
Coronary vessles are exposed and grafts are applied in order:
1) distal grafts are applied first
2) LIMA
3) Proximals on aorta |
|
|
Term
| What happens after the distal grafts are applied? |
|
Definition
After placement of all distals:
-the x clamp is off and a partial occlusive clamp may be put on or unclamped completely.
-then if a valve procedure, the valve will be evaluated, then proximals will be applied. |
|
|
Term
| What agent is used during CPB? |
|
Definition
| Isoflurane is administered via the CPB circuit. |
|
|
Term
| What temperature is the heart kept at during CPB? |
|
Definition
-The temperature is decreased to 34oC usually by “drifting” down.
-Temperatures below 28oC may result in coagulopathies simply by the denaturing of the proteins. |
|
|
Term
| When does rewarming begin from CPB? |
|
Definition
-Rewarming will occur when 2/3 of the procedure is done (about the same time that the last distal is sewn, which typically is the LIMA).
-Warming is a gradual procedure. |
|
|
Term
| How warm does the patient need to be to come off CPB? |
|
Definition
| The pt is safe to come off CPB when when the bladder or core temperature is > or equal to 37 oC |
|
|
Term
| What should the MAP be maintained at when coming off bypass? |
|
Definition
|
|
Term
| What should the PAP & CVP be maintained at when coming off bypass? |
|
Definition
| PAP and CVP will be close to 0 since the heart is decompressed/empty. |
|
|
Term
| What position might the position need to be placed in during removal of the cross clamp? |
|
Definition
|
|
Term
| What are possible color combinations of lead wires? |
|
Definition
Blue - atrial
White- Ventricular |
|
|
Term
| If the heart is fibrillating during rewarming, what should be done? |
|
Definition
-Defibrillation @ 20-30 joules
-Fibrilation of the heart might occur when it gets to a temperature of 32 degrees C |
|
|
Term
| Describe the process of separation from bypass. |
|
Definition
This is diverting blood back into the patient's heart.
-First the venous drainage to the CPB is occluded
-The arterial pump flow is slowly decreased
-The reservoir slowly empties into the patient
-The heart gradually takes back over |
|
|
Term
| What information might the CRNA want from the perfusionist when coming off pump? |
|
Definition
1. the current flow rate of the pump
2. the volume in the pump reservoir
3. the oxygen saturation of the venous blood returning to the pump from the patient (SvO2). |
|
|
Term
| What does the current flow rate of the pump tell us? |
|
Definition
| the current flow rate of the pump indicates the stage of weaning as it is decreased. |
|
|
Term
| What does the volume in the pump reservoir tell us when coming off CPB? |
|
Definition
| the reservoir volume indicates how much blood is available for transfusion to fill the heart and lungs once CPB is discontinued |
|
|
Term
| What does the oxygen saturation of the venous blood returning to the pump from the patient (SvO2) tell us when coming off CPB? |
|
Definition
| The saturation of venous blood gives an indication of the adequacy of peripheral perfusion during bypass. |
|
|
Term
| What are the 3 steps for coming off bypass? |
|
Definition
1- Progressively stopping venous return to the pump
2- Lowering the pump into the aorta
3- Bypass termination |
|
|
Term
| What happens to the heart when venous return to the pump is slowly decreased? |
|
Definition
This increases venous line resistance causing:
-RAP to increase
-blood flow through the RV instead of all draining into the pump
This leads to:
-Increased CO -> increased preload -> increased ejection |
|
|
Term
|
Definition
The lowest filling pressure that provides an adequate CO
-Patients with good LV function PCWP = 8-12 mmHg
- Pts with poor LV function PCWP = 20 mmHg or higher. |
|
|
Term
|
Definition
-the rise in preload causes the heart to begin to
contribute to the CO.
-can keep on partial bypass to wash out vasoactive substances from lungs before terminating CPB. |
|
|
Term
| WHat is the rate of change of flow when coming off bypass? |
|
Definition
Reduced pump outflow requirement:
-perfusionists reduce the amount of arterial blood returned from the pump by 0.5 – 1.0 L/minute increments.
-This allows for gradual reductions in pump flow rates.
-If preload is maintained with a rate of flow <1L/min, bypass can be terminated |
|
|
Term
| What BP is needed to terminate bypass? |
|
Definition
|
|
Term
| What are some potential complications when coming off bypass? |
|
Definition
1) Aortic dissection
2) Carotid or innominate artery hyperperfusion
3) Air embolus
4) Pump failure
5) Postperfusion syndrome (pumphead) |
|
|
Term
| How does CPB cause aortic dissection? |
|
Definition
| -caused by the cannula orifice being situated within the arterial wall not in the true lumen, possibly because a dissection was created during the cannulation process. |
|
|
Term
| How is an aortic dissection diagnosed during cardiac surgery? |
|
Definition
-Occlusion may of the arterial true lumen may cause low or zero blood pressure to be measured by the radial art line depending on the site of dissection
-Inappropriately high arterial line pressure
-Organ hypoperfusion: May see ischemia, or aortic insufficiency, oliguria, pupil asymmetry
-Visual inspection or palpation
- TEE |
|
|
Term
| How is an aortic dissection treated during cardiac surgery? |
|
Definition
-D/C bypass
-surgeon must reposition or replace arterial cannula |
|
|
Term
| How does CPB cause Carotid or innominate artery hyperperfusion? |
|
Definition
| Caused by most or all of pump outflow being directed into the carotid artery, usually right side |
|
|
Term
| How is an Carotid or innominate artery hyperperfusion diagnosed during cardiac surgery? |
|
Definition
•Prevention includes:
-surgeon’s vigilance
-CRNA checking the lateral carotids pulses without thrills after cannulation
• Diagnosis:
-Ipsilateral branching of the face
-Ipsilateral pupillary dilation
-Ipsilateral conjunctival edema
-Low BP measured by the left radial or femoral arterial catheter, a right radial art line may show HTN due to innominate artery hyperperfusion |
|
|
Term
| How is an Carotid or innominate artery hyperperfusion treated during cardiac surgery? |
|
Definition
- Reposition the arterial cannula
-Consider measures to reduce cerebral edema such as mannitol, head-up position |
|
|
Term
| In relation to CPB, when is heparin usually administered? |
|
Definition
-Before bypass,
-usually during placement of the aortic purse strings.
-Must be given prior to cannulation |
|
|
Term
| Where should heparin be given? |
|
Definition
-In a central line.
-Always aspirate the line first |
|
|
Term
| How long after giving heparin should you check an ACT? |
|
Definition
|
|
Term
| What value should ACT be prior to starting CPB? |
|
Definition
|
|
Term
| What must be done prior to drawing an ABG? |
|
Definition
-Heparin flush the syringe
-The ABG machine must have a heparinized sample for the results to be generated. |
|
|
Term
| What is a normal ACT value? |
|
Definition
| Normal ACT = 90-120 seconds (100 sec) |
|
|
Term
|
Definition
-Binds to antithrombin III (AT-III) a protease inhibitor.
-Increases the speed of the reaction between AT-III and several activated clotting factors (II, IX, X, XI, XII, XIII) |
|
|
Term
| Chemically, what is heparin? |
|
Definition
-a mixture of highly electronegative polyanionic electrolytes
-It is a water- soluble mucopolysaccharide. |
|
|
Term
| Describe the metabolism of heparin |
|
Definition
-heparin’s half-life approximately 90 minutes during normothermia.
-Hypothermia decreases the rate of heparin decay.
-Metabolism is by heparinase in the liver. |
|
|
Term
| What are the side effects of heparin? |
|
Definition
-with the exception of bleeding, very few.
-May see mild reduction in systolic BP, vasodilation and rarely ananphylaxis. |
|
|
Term
| What is the typical heparin dose? |
|
Definition
-initial dose 300 units/kg or 3 mg/kg to 400 units/kg.
-Additional doses depend on ACT. |
|
|
Term
| What are you safe to do after giving heparin? |
|
Definition
-Turn off the peripheral IVs
-They won’t clot once you’ve given the heparin |
|
|
Term
| What BP is needed for aortic cannulation? |
|
Definition
-SBP of 90-100mmHg
-Start lowering the pressure prior to this to prevent aortic dissection and to assist with cannulation. |
|
|
Term
| What are you watching for during aortic cannulation? |
|
Definition
| Air in the field. Bubbles will be an indicator. |
|
|
Term
| What is a fast way to treat HoTN at this point? |
|
Definition
| By having the perfusionist give fluid directly into the aortic cannula. |
|
|
Term
| What is a potential complication during aortic cannulation? |
|
Definition
Obstruction of the carotid blood flow
Assess:
-Pupils for symmetry
-B/L carotid pulses
-A thrill in a carotid |
|
|
Term
| What might happen during insertion of the retrograde cardioplegia line? |
|
Definition
The heart is lifted and manipulated during this time resulting in:
-arrythmias
-HoTN |
|
|
Term
| What does the CRNA need to do during insertion of the cardioplegia line? |
|
Definition
-Hand ventilate the patient
-The surgeon will hand a pressure transducer tubing to be connected to the PA transducer which is flushed.
:This will allow coronary sinus pressure monitoring during retrograde cardioplegia. |
|
|
Term
| What might the CRNA give after the aortic and retrograde cannulas are inserted? |
|
Definition
-More NDMR and Benzo
-Limit the amount of narcotic and bdz is desired for early weaning and extubation. |
|
|
Term
| What should be done with the SG catheter during CPB? |
|
Definition
-SG catheter is withdrawn 5cm to prevent perforation of the pulmonary artery and to keep from going into over-wedge during bypass.
-Pulling the catheter all the way back into the right ventricle risks getting a perforation of the ventricle as the heart is manipulated during surgery. (done just prior to CPB )
-Flip the PA line stopcock up so that perfusion can read the retrograde cardioplegia waveform. |
|
|
Term
| What vent settings are used during CPB? |
|
Definition
| Ventilation is stopped once CPB is started. |
|
|
Term
| What should the CRNA be looking for once CPB is started? |
|
Definition
Malposition of the cannulas:
-facial swelling,
-conjunctiva swelling,
-increase CVP,
-jugular venous distention
Pupils should be small, symmetrical, and pinpoint. |
|
|
Term
| What should be recorded on the flow sheet once CPB is initiated? |
|
Definition
-On and Off CPB times
-ACC times
-Temp
-MAP with an *
-UO
-EKG rhythm |
|
|
Term
| What can be done to treat the decreased readings on the cerebral oximetry? |
|
Definition
-Increasing flows
-Increasing CO2 retention
-Increasing temperature
-Increasing hematocrit |
|
|
Term
| What UO level is a sign of decreased renal perfusion? |
|
Definition
< 1 mg/kg/hr.
-Urine outputs of 300-1000 ml/hr are not uncommon. |
|
|
Term
| What can happen to the conjunctiva during CPB? |
|
Definition
| Often the conjunctiva get edematous during CPB. |
|
|
Term
| What gtt is continued during CPB? |
|
Definition
Insulin
Blood sugars will be checked about every 30 minutes while on bypass. |
|
|
Term
| What is given when the LIMA is grafted onto the LAD? |
|
Definition
Procardia is given intranasally/sublingually when the surgeon grafts the LIMA to the LAD.
-The dose is 10mg. |
|
|
Term
| What should the PAP be during CPB? |
|
Definition
|
|
Term
| What does the placing of the LIMA indicate? |
|
Definition
-2/3 of the procedure is done
-The last graft to be placed
-It’s time to give blood if needed
-Rewarming is started |
|
|
Term
| What happens after the bulldog clamp is removed? |
|
Definition
-the cross clamp will be removed shortly.
-In preparation for this, give:
Lidocaine 100 mg,
MgSo4 2g
1g CaCl |
|
|
Term
| Why do we give MGSO4 prior to cross-clamp removal? |
|
Definition
-2gm given IV just prior to cross clamp removed to help prevent V-arrhythmias.
-Hypomagnesemia has been demonstrated in up to 70% of patients after CPB and may predispose the patient to ventricular arrhythmias. |
|
|
Term
|
Definition
| 100mg prior to cardioversion. |
|
|
Term
| If the patient requires a second defibrillation, what should the CRNA consider? |
|
Definition
| If the patient must be defibrillated more than once, consider antiarrythmics like amiodorone. |
|
|
Term
|
Definition
| give 1gm after the cross clamp has been removed and just prior to separation from CPB. |
|
|
Term
|
Definition
It is helpful in:
- increasing MAP
- may assist in augmenting LV function, RV function and CI after emergence from CPB. |
|
|
Term
| What needs to be done with the transducers prior to coming off CPB? |
|
Definition
| Rezero the transducers prior to coming off. |
|
|
Term
| What is a big factor in determining how well a patient will do when coming off CPB? |
|
Definition
|
|
Term
| What happens to patients with good LV function when coming off CPB? |
|
Definition
| those with good LVF are usually quick to develop a good BP and CO and come off easily; |
|
|
Term
| What happens to patients that are hypovolemic when coming off CPB? |
|
Definition
Depends on their LV function
-good LVF respond well to volume
-patients with poor LVF come off with a sluggish, poorly contracting heart that progressively distends |
|
|
Term
| How do you treat a patient with poor LVF when coming off CPB? |
|
Definition
If the heart is contracting poorly and progressively distends:
-CPB is usually reinstituted
-inotropes are necessary.
-If the length of the bypass period is > 120 minutes, can see impaired myocardial performance. |
|
|
Term
| What happens to the heart after the ACC is removed? |
|
Definition
| the ventricle will slowly start beating. |
|
|
Term
| What should the CRNA do once the pacemaker leads are sewn in place? |
|
Definition
| the pacemaker should be checked for proper functioning and capture. |
|
|
Term
| What setting is the PM usually put in? |
|
Definition
-Asynchronous is the usual setting (less chance for Bovie interference): DOO, 90- 100 bpm, 20mA, 150ms. Consider a higher rate for patients with regurgitant lesions.
-(DDD sometimes asked for 90bpm, 20mA, sensitivity A 15 V 2, refractory interval A 300 AV 200. Consider a higher rate for patients with regurgitant lesions). |
|
|
Term
| What gtts are started when coming off CPB? |
|
Definition
o Epi
o Vasopressin
o Milrinone
o Levophed
o Insulin (most likely still running) |
|
|
Term
| What needs to be considered if Primacore (milrinone) is given? |
|
Definition
-If decision is made to use, give very slowly during rewarming.
-Start infusing at a rectal temp of 32.5 deg and give slowly as to complete it by the time the temp reaches 35.0.
-Hypotension from vasodilatation is very common, especially if given quickly. |
|
|
Term
| What is the dose for Primacore? |
|
Definition
| Loading dose is 50ug/kg followed by an Infusion of .5-.75ug/kg/min. |
|
|
Term
| What medication should be available when coming off CPB? |
|
Definition
| Confirm that Heparin is in room for crash back on CPB. |
|
|
Term
| How should the patients airway/ventilation be managed when coming off CPB? |
|
Definition
-Check ventilator connections
-consider suctioning the ETT
-Increase the O2 Flow Rate.
-Start the ventilator at low tidal volumes when blood is going thru the heart so the ventilator will not get in the way of the surgeon. |
|
|
Term
| Why are low Vt used when coming off CPB? |
|
Definition
1) avoid stretching the internal mammary artery and
2) improve surgical visibility. Hand bagging may be necessary.
3) not to stretch the LIMA. |
|
|
Term
| When/why should the CRNA go to full Vt? |
|
Definition
When:
-Before coming off pump
-After asking the surgeon
Why:
-Eliminate atelectasis |
|
|
Term
| What respiratory value should the CRNA look for before coming off COB? |
|
Definition
|
|
Term
| What might happen to the PA catheter when coming off CPB? |
|
Definition
| The PA cath may appear wedged until volume is given or may just plain be wedged. Even after pulling the catheter back 5cm at the start of bypass, it is not uncommon to have the cath wedged when coming off bypass. |
|
|
Term
| What should the CRNA do to the PA catheter when coming off CPB? |
|
Definition
| Turn the stopcock back to a neutral position on the PA tracing. |
|
|
Term
| What might be given prior Protamine administration? |
|
Definition
Hydrocortizone 100 mg or 50 mg of
Benadryl is administered after coming off CPB.
-( Diabetic Patients: Higher incidence of Protamine reactions) |
|
|
Term
|
Definition
| Neutralization: heparin (acid) is neutralized by protamine (base) at a ration of 1 –1.3 mg protamine per 100 units of existing heparin. |
|
|
Term
| What are the 6 “Cs” of CVP when coming off bypass? |
|
Definition
Cold- temp 37 degrees before ending CPB
Conduction- Need HR 70-100
Calcium- treat if Ionized Ca is low
CO
Cells
Coagulation- PLTs |
|
|
Term
| How are rhythms treated when coming off bypass? |
|
Definition
-SB: Atropine
-ST- treat underlying cause
-Rhythm- attempt NSR
-AV sequential pacing may be needed
-SVT: cardioversion
-3rd degree heart block: pacing |
|
|
Term
| What are the 4 “Vs” of CVP when coming off bypass? |
|
Definition
Ventilation
Vaporizer- turn off
Volume expanders- to incr preload
Visualization |
|
|
Term
| What ventilation tasks should be done when coming off CPB? |
|
Definition
-check ABG’s,
-expand lungs,
- pulse oximeter on,
-ventilation started prior to an attempt to terminate CPB |
|
|
Term
| What should be visualized prior to coming off CPB? |
|
Definition
-contractility,
-distention of chambers,
-wall motion abnormalities |
|
|
Term
| What are the 5 “Ps” of CVP when coming off bypass? |
|
Definition
•Protamine – dose should be calculated and drawn up
•Pressure – check calibration of transducers
•Pressors – have available
•Pace r- pacemaker should be available
•Potassium – blood chemistries checked |
|
|
Term
| What needs to be checked immediately after coming off bypass? |
|
Definition
|
|
Term
|
Definition
-protamine is the specific antagonist of
heparin’s anticoagulant effect.
-Protamine is a strong base (alkaline) and simply neutralizes heparin, which is a strong acid. |
|
|
Term
| Who might have an allergic reaction to protamine? |
|
Definition
Allergic reactions have been described in patients:
-receiving protamine containing insulin preparations,
-patients allergic to fish
-In the presence of circulating antisperm antibodies in vasectomized or infertile males. |
|
|
Term
| When should protamine be given? |
|
Definition
-Immediately after stopping CPB
-Given after the venous cannula is removed. |
|
|
Term
| How should protamine be given? |
|
Definition
| Give it through a buretrol IVPB at about 50-100mg/min. |
|
|
Term
| What is usually given with protamine? |
|
Definition
| We usually co-administer Calcium chloride (.5-1gm IVP) concomitantly with the Protamine and give slowly at 5 mg/min |
|
|
Term
| What are the S/S of a protamine anaphylactic reaction? |
|
Definition
-severe hypotension (vagoplegia) with low SVR and filling pressures due to an overproduction of nitric oxide.
-NO causes massive vasodilation in vascular smooth muscle that’s unresponsive to vasopressors.
-Severe pulmonary hypertension and right sided heart failure can also occur. |
|
|
Term
| How long does a protamine reaction usually last? |
|
Definition
5-10mins
Usually if you stop the infusion, the S/S will resolve
Once hemodynamics return to normal, restart the infusion slowly while watching the PA pressure |
|
|
Term
| How is a protamine anaphylactic reaction treated? |
|
Definition
Methyene blue. A competitive inhibitor of cGMP wich reduces the response of cGMP-mediated vasodilators (i.e
nitric oxide. 1-2 mg/kg, up to 5 mg/kg. |
|
|
Term
| What should the CRNA be doing while the surgeon is suturing the chest closed? |
|
Definition
|
|
Term
| WHat should be checked immediately after the chest sutures are finished? |
|
Definition
|
|
Term
| When should cell saver blood be given? |
|
Definition
-After the aortic cannula is out
-After protamine is given |
|
|
Term
| What might need to be given if the patient has been on plavix or extraordinarily long CPB? |
|
Definition
|
|
Term
| What is the problem with post-op shivering in cardiac patients? |
|
Definition
Increased O2 demands
Use every method to prevent this:
-Warm irrigation fluids
-Warm ambient temp
-Vasodilators and increased bypass flows during warming
-Lengthening rewarming time
-Limiting the time the chest is open |
|
|
