Cardiac Flashcards
EKG with cor pulmonale
Right atrial hypertrophy - peaked p waves II, III, aVF
RVH - right axis deviation, partial or complete bundle branch block
Goals with AS
- Maintain sinus rhythm, esp avoiding tachycardia
- Adequate preload
- Maintain after load. CPP = aDP - LVEDP
- Maintain Contractility
AS gradient requiring surgery
50mmHg
CVP 22, PA 44/25, CI 1.5L/min, what is going on?
Tamponade
- Beck’s Triad: hypotension, JVD, muffled heart sounds
- pulsus paradoxus
Tx (fast, full, tight)
- Elevated HR (CO is HR dependent)
- Fluids
- Ionotrope support (epi +/- ketamine)
- Spontaneous vent
- Alert surgeon –> back to OR
- CVP dominant x descent, minimal y descent
Hemodynamic changes with aortic cross clamp
Proximal: inc after load, inc BP, CVP, PAOP, dec CO and EF
Distal: Dec RBF and mesenteric BF
inc MvO2, acidosis,
Hypotension on CPB
Low CO from hemodilution or Low SVR
Inc flow rate or give Neo
Steps coming off bypass
Normothermia Midazolam to prevent awareness Make sure monitors, machine, alarms are on Correct lab abnormalities - anemia, electrolyte Heart de-aired Start ventilation Check TEE to assess function Have pacing on standby
Side effects of nitroprusside infusion
CN toxicity
Metabolic acidosis
Arrhythmia
Tachyphylaxis
Tx = 100%O2, hydroxycobalomin
Heparin for bypass
3-4 U/kg
ACT 300-400 (480)
Protamine 1mg/100U heparin - acid base reaction
Goals with HOCM in pregnancy
Continue beta blockers
Maintain preload
Maintain SVR
Maintain slow normal rate and SR
Avoid spinal (sympathectomy)
Epidural and GA ok
Pitocin - ok if given slow
Afib = cardioversion or esmolol
How does IABP work?
Sits in aorta, deflates during systole reducing afterload and inflates during diastole inc coronary perfusion
This dec myocardial work, inc O2 supply to myocardium
How would you evaluate an AICD preoperatively?
Baseline cardiovascular function, underlying rate and rhythm
Indication for AICD
Functioning properly, battery, any shocks
Contact manufacturer
Behavior when exposed to magnet
If within 6 inches, magnet/ manufacturer to deactivate defibrillator and place pads
Set to asynchronous DOO
Avoid cautery or use bipolar or short bursts
How to protect spinal cord perfusion during aortic cross clamp
Adequate BP Hypothermia CSF drain Shunt across clamp Avoid vasodilators that inc ICP and this spinal cord perfusion pressure
Cardiac considerations for Down syndrome
Any endocardial cushion defects
ASD, VSD, PDS, TOF
Uncorrected —> pulmonary HTN
Indications for endocarditis PPx
Dental, skin or resp procedure Prosthetic material Previous BE Unrepaird CHD Repaired CHD with 6 months Residual defect Transplant with valvulopathy
Would you delay the case to optimize blood pressure? How long?
I would look at BP trends, evidence of end-organ damage (LVH, renal, vascular disease).
Evaluate the patient for symptoms of end organ damage as well - headache, chest pain, EKG, pulmonary edema, SOB
If urgency of case did not allow optimization over several weeks, I would lower to 140/90
Centrifugal vs roller pump
Roller pump
- partial compression of tubing by two roller heads
- NOT sensitive to preload or afterload
- can deliver pulsatilla flow
- reliably delivers certain flow based on pump speed
- more RBC trauma
- potential for large air embolism
Centrifugal
- rotational force responsible for forward flow
- sensitive to preload and afterload
- will not work if senses air
- less trauma to RBCs
Alpha stat vs. pH stat, which one is preferable
Slightly better neurological outcomes with alpha-stat in adults
- hypothermia inc solubility of CO2 and dec arterial pH and partial pressure of CO2
pH stat adds CO2 to oxygenator to maintain PaCO2 of 40 and pH 7.4
- ischemia not emboli primary mechanism in peds = pH stat preferred in peds
Acute vs chronic mitral regurg
Acute = left atrial overload without compensatory ventricular dilation—> dec CO, pulm edema, RV failure
Elevated LVEDP and tachycardia increases risk of ischemia
Temp monitoring for bypass
Measure core and shell due to temp gradient that develops during cooling and rewarming
- nasopharyngeal and toe or rectal
- ensures adequate cerebral cooling and avoid large temp gradients (>10deg) that can lead to bubble formation in blood
Goals for mitral regurg
Fast full, forward
Maintain HR, preload + afterload reduction
Adequate anesthesia during laryngoscopy to avoid HTN, tach inc MR and myocardial O2 demand
Avoid over aggressive induction, hypotension, BRADYCARDIA –> worsening regurg and dec coronary perfusion
Either lead to ischemia—> AFIB
Low reservoir volume, what would you do?
Reduce pump flows
Add fluid
Look for heart manipulation, kinking, malposition of venous cannula
Why is de-airing important?
Lung re-inflation recruits alveoli, inc pulm blood flow displacing air into left heart where it can be removed with a vent
This dec end organ damage from embolization to cerebral and coronary arteries
Inc PA pressure and dec BP during bypass wean
LV failure
- inc afterload (esp after MVR)
- graft failure from clot, kink, air
- poor CBF from hypotension, emboli, spasm, tachycardia
- hypovolemia
- acidosis
- hypoxemia
Failure to wean from bypass causes and solutions
Poor pre-op EF and need for ionotropes
Aortic cross clamp time
Severe MR
Ensure adequate volume, temp
Correct acidosis, anemia, hypoxemia, labs
IABP - dec afterload, inc coronary perfusion
AICD code VVE-DDDRO
Shock - ventricular
Anti-tach pacing - ventricular
Electro gram detection
Pacing - dual Sensing - dual Triggered or inhibited response to sensing - dual Rate responsiveness Not capable of multi site pacing
What are the Debakey classifications
Type 1 - aortic dissection ascending aorta distal to abdominal aorta
Type 2 - ascending and do not extend past innominate
Type 3 - beyond left subclavian to abdominal
Would you place a lumbar drain for thoracic dissection repair?
CSF drainage could facilitate SC perfusion given inc in CSF pressure with cross clamp
Have risk benefit discussion with surgeon. Is there time to delay systemic heparinzation 60 minutes or up to 24 hours with traumatic placement?
Where would you places line for aortic dissection repair?
Consider upper and lower extremity lines to identify inadequate perfusion distal to cross clamp.
Upper extremity a-line in right to avoid interference from clamp
How does hypothermia affect coagulopathy?
Defects in platelet aggregation and adhesion
Below 33 enzyme activity is abnormal
EKG with hyperK
Peaked T-waves Prolonged PR Widened QRS Loss of P-wave —> VF
How long to delay elective surgery following:
Balloon angioplasty
BMS
DES
2 weeks
4 weeks
consider at 3 months stent risk < surgery delay but ideally 6-12 months
Mechanism of TXA
Binds plasminogen preventing prevents its interaction/activation with fibrin –> plasmin
Prolonged R-time
Low clotting factors, heparin, LMWH
Give FFP
Prolonged K time
Dec thrombin or fibrinogen
Give cryo
Indications for further cardiac work-up with MVP
Significant MR, syncope, chest pain or CHF
Hypotension and inc PA pressures following protamine cause
Histamine release or Type III protamine reactions
- release thromboxane A2 –> inc PA pressures and right heart failure
- prevention = diluting and giving slowly
- avoid giving thought PAC (pHTN) or bypass circuit (clot)
Recommendations regarding peri-operative beta blockade
Continue in those on BB
Consider for vascular and intermediate surgeries with risk factors - hx ischemic disease, CHF, CVA, DM, CRI
DDX for pacing failure
MI Lead dislogement Lead failure Inadequate amplitude Hypercarbia Acidosis
DDX for post-CABG bleeding
1 = platelet dysfunction
Fibrinolysis Hemodilution Poor surgical hemostasis Inadequate heparin reversal hypothermia DIC
Check ACT, PT/PTT, Fibrinogen, TEG
What are some cardiac and non-cardiac causes of AFIB
Cardiac
- valvular, HTN, LVH, SSS
Non-cardiac
- idiopathic, PE, thyroid, etOH
What are the risk factors for stroke with AFIB
CHADS2VASC
- CHF
- HTN
- Age >65
- DM
- Stroke
- Vasc disease
- sex female
1 = consider 2 = likely benefit from anticoagulation
How would you treat hypotension in a patient with a heart transplant?
- check for arrhythmia
- maintain preload
- direct vasoconstrictor (Neo)
- isoproterenol or epi gtt
- check for anaphylaxis, PE, other causes
Notes:
No vagal influences/response
- higher resting HR
- no reflex bradycardia
Risk factors for stent thrombosis
#1 - cessation of DAPT surgery - inc catecholamines, inc platelet agg, dec fibrinolysis
small lesion multiple stents overlapping stens malpositioned or residual dissection long stents left main or ostial stents low EF DM, CRF, old age
How is bridging therapy employed?
when bleeding risk on thienopyridine too high
- discontinue 5-7 days before surgery
- continue ASA
- start short acting platelet inhibitor (tirofiban) 2-3 days before surgery
- consider concomitant heparin gtt
- discontinue tirofiban 6 hours before surgery
A-line waveform changes when moving further from the heart
SBP inc + DBP dec = widened pulse pressure
Dicrotic notch disappears
MAP minimally affected
Ddx for narrow pulse pressure
Hypovolemia AS Tamponade Systolic HF Overdampening
DDx for widened pulse pressure
Isolated systolic HTN (elderly pt) AI Thyrotoxicosis Distributive shock Underdampening
CVP waveform with A-fib
Loss of A-wave
Prominent C-wave
CVP waveform with AV dissociation
Cannon A-wave
CVP waveform with TR
Broad tall C-V wave
No X-descent
resembles RV pressure tracing
CVP waveform with RV ischemia
Inc CVP
Tall A & V
Steep X & Y descent
Resembles M or W pattern
Same as constrictive pericarditis
CVP waveform with tamponade
Dominant X descent
Attenuated Y descent
Normal PAP range
15-30/5-15mmHg
Diastolic pressures inc compared to RV pressures
What is a normal SvO2?
70-75%
Ddx for inc SvO2
Low O2 extraction
- sepsis
- cyanide
- MethHb
- CO
- hypothermia
High CO
- sepsis
- burns
- L-R shunt
- AV fistula
- excessive ionotrope
- Hepatits, pancreatitis
Ddx for dec SvO2
Dec Hb
- anemia
- hemolysis
Dec CO
- MI
- CHF
- hypovolemia
Dec SaO2
Inc VO2 - shivering
How does clopidogrel work?
ADP receptor inhibitor which inhibits platelet activation
If the patient had 90% carotid occlusion on surgical side and 100% occlusion on opposite side, which side would you place the central line?
I would prefer to do it on the side of 100% occlusion because if I hit the carotid artery, there is no risk of further injury since the vessel is already blocked.
If i started it on the surgical side, I would run the risk of total occlusion of circulation to the brain
What is meant by watershed areas?
areas of circulation that border between the 2 carotid arteries.
if patient had poor perfusion from non-clamped carotid artery, high likelihood of stroke in the watershed area
Changes with EEG during carotid cross clamp, surgeon says he cannot release the clamp. How do you respond?
Ensure patient is not hypoxic, hypotensive, anemic
Ensure appropriate depth of anesthesia
I would ask to place a shunt or
inc BP to improve cerebral perfusion while watching for signs of myocardial ischemia
Why not place a carotid shunt prophylactically in all patients undergoing CEA?
Not without risks
- serves as a conduit for small emboli –> stroke
What are the benefits of off-pump CABG vs. on-pump?
OPCAB = avoidance of CPB machine
- inflammatory response
- neurologic injury
- coagulopathies
- platelet dysfunction
- fibrinolysis
- renal impairment
- arrhythmias (afib)
On-pump
- technically easier
- hemodynamic changes managed by perfusionist more easily
How might recent MVR contribute to LV failure coming off bypass?
Lose low resistance outflow to RA –> inc LV after load
What is pulsus paradoxus?
Exaggeration of normal variation in SBP and pulse during inspiration.
More negative intrathoracic pressure –> inc VR –> inc RV volume and bulging of septum into LV
Describe the hemodynamics of aortic outflow tract obstruction and issues that are complicated by neuraxial anesthesia
CPP = aorticDBP - LVEDP
In AS, LVEDP is elevated –> dec CPP
Thus to maintain it is critical to maintain aortic BP = MAP
Neuraxial –> vasodilation and dec MAP
How would you respond to a request for neuraxial anesthesia in a patient with CHF and EF 20%?
I would not place a spinal because this results in sympathectomy –> venous pooling –> dec SV in a patient with already poor EF –> cardiac compromise
After surgery, the patient complains of chest pain and you note new ST segment elevation on the bedside monitor. How will you proceed?
What if he develops hypotension, dyspnea and rales?
I would:
- call for help - apply defibrillator, activate STEMI team
- obtain 12-lead EKG to confirm and determine location of MI
- Treat any pain (MONA-B)
- Apply oxygen
- Nitrates (unless inferior MI or hypotensive)
- Beta blocker (unless hx asthma, hypotensive)
- Aspirin
Then consider PCI, heparin gtt (fibrinolytic checklist), ionotropes +/- diuretic with CHF
How would you treat a protamine reaction?
Volume O2 Epi CaCl Pacing Go back on bypass
What are some causes of long QT?
Suspect with syncope with activity
Drugs
- TCAs
- many antibiotics
- metoclopramide
- haldol
Genetic
Myocardial
- MI
- cardiomyopathy
Electrolytes
- Low K, Mag, Ca
How would you manage new finding of prolonged QT with syncope?
Identify cause
Cardiology consultation
Avoid precipitants - meds, hypothermia, ischemia, low electrolytes
Avoid inc sympathetic tone
Beta blockers
ICD
New onset PVC or bigeminy, what do you think? How would you manage?
I am concerned this represents structural or ischemic heart disease which would place this patient at risk for inc morbidity and mortality.
Rule out other causes
- stimulants
- acidosis, hypoxemia, hypo/er K+, hypoMag
Tx - Lidocaine, beta-blockers (propanolol, metop)
Describe the ACC/AHA algorithm for patients undergoing non-cardiac surgery
Emergent –> go to OR
Non-Emergent
–> screen for active cardiac conditions and treat (MI w/in 7 days, unstable angina, decompensated CHF, significant arrhythmia or severe valvular disease)
Low risk surgery –> go to OR
Intermediate or high-risk
- –> assess functional capacity
- –> >4 METS –> go to OR
<4 METS or unknown
- 1-2 risk factors –> proceed with HR control or consider noninvasive testing
- 3+ risk factors –> consider testing if it will change management
Aortic cross-clamp is applied and BP 200/100, PA 50/30, CI 1.3, how will you treat?
I would ensure patient is not hypoxic, check for ST changes and arrhythmia.
Give nicardipine to dec afterload
+/- ionotrope
Nitroglycerin if ST changes indicating MI
What are the signs of digoxin toxicity?
AF/A-flutter + heart block (bigeminy common)
Tx = Digibind or atropine –> pacing –> epi infusion
Ddx for poor r-wave progression
Previous anteroseptal MI LVH RVH Incorrect lead placement Normal variant
