Cardiovascular

Question 1

What is MOST LIKELY the primary rationale for the use of long-term beta-blocker therapy to slow disease progression in chronic heart failure with a reduced ejection fraction?

Answer 1

Prevention of catecholamine induced toxicity
Beta-blockers such as metoprolol function primarily by interrupting signaling at myocardial beta1-adrenergic receptors, which reduces metabolic catecholamine cardiotoxicity and slows deleterious cardiac remodeling. This is thought to be the main mechanism of beta-blockers in reducing mortality in patients with heart failure.

Question 2

A patient with severe aortic insufficiency is scheduled to undergo surgical aortic valve replacement with cardiopulmonary bypass. Which of the following specialized techniques would be MOST appropriate for myocardial protection during the procedure?

Answer 2

Retrograde cardioplegia
Retrograde cardioplegia administration via the coronary sinus is indicated in the setting of obstructive coronary artery disease, aortic insufficiency, or procedures involving manipulation or distortion of the aortic valve or coronary ostia that would make antegrade cardioplegia difficult or impossible to deliver. However, a combination of antegrade and retrograde cardioplegia approaches is often used.

Question 3

A 65-year-old woman with New York Heart Association class IV heart failure presents for heart transplantation. Which of the following is MOST true regarding the donor heart after transplantation?

Answer 3

Reflex bradycardia from phenylephrine administration is absent
Due to transection of the cardiac autonomic plexus during transplantation, the donor heart will not exhibit reflex responses such as reflex bradycardia with the administration of phenylephrine nor will it respond to hypovolemia or exercise. With the loss of parasympathetic tone, the resting heart rate is usually 90 to 110 bpm, and there is no heart rate response to anticholinergics.

The denervated heart has an accelerated rate of atherosclerotic disease resulting in a significant 5-year incidence of coronary artery disease. Recipients of donor hearts do not experience angina because of the denervation.

Question 4

Which of the following is MOST true regarding the coronary arteries?

Answer 4

The LCx supplies the anterolateral pap muscles
The heart is supplied by 2 coronary arteries, left and right, that originate at the root of the aorta. The left circumflex artery, a branch of the left coronary artery, supplies the posterolateral left atrium and ventricle and anterolateral papillary muscle (left anterior descending artery also provides blood flow).

Question 5

In which of the following scenarios is a preoperative resting 12-lead ECG recommended as a component of the perioperative cardiovascular evaluation?

Answer 5

87yr M with TIA undergoing robotic prostatectomy
According to the American College of Cardiology/American Heart Association Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery, if a patient has a known cardiac condition or cerebrovascular disease, a preoperative ECG should be performed unless the surgery is low risk. In general, endoscopies, ophthalmologic procedures, and superficial procedures are considered low-risk procedures, while most others are considered at least intermediate risk.

Question 6

Which of the following BEST describes the Bainbridge reflex?

Answer 6

Increased preload streches the atrial fibers increasing heart rate
The Bainbridge reflex results from an increase in cardiac preload sensed by type B stretch-sensitive mechanoreceptors in the right atria and cavoatrial junction that increase the heart rate.

TrueLearn Insight: The oculocardiac reflex is a result of pressure applied to the eye or traction of the extraocular muscles. This is sensed by stretch receptors in the extraocular muscles that then send afferent signals via the short- and long-ciliary nerves, which merge with the trigeminal nerve at the ciliary ganglion. The trigeminal nerve carries this signal to the Gasserian ganglion. This efferent limb (vagus nerve) then leads to an increase in parasympathetic tone and bradycardia. If an antimuscarinic is applied during eye surgery, the incidence of bradycardia can be reduced.

Question 7

A 52-year-old female with a history of coronary artery disease and hypertension was found down at home, just 12 hours after returning home from the hospital. She was recently discharged home five days after a hysterectomy procedure for uterine fibroids. Post-operatively, she developed a urinary tract infection. She received intravenous cefepime in the hospital for three days. On the day of discharge, she was provided with a prescription for ciprofloxacin. Her vital signs today, on arrival to the hospital were:

Temperature: 38.2°C
Heart rate: 126 bpm
Blood pressure: 76/42 mmHg
Respiratory rate: 28 / min
SpO2: 94% on room air

She is intubated due to respiratory distress. Her creatinine is 2.4 mg/dL from a baseline of 1.2 mg/dL. The following hemodynamic variables were also found:

ETCO2: 42 mmHg
CVP: 4 mmHg
PCWP: 8 mmHg
CI: 5 L/min/m2
SVR: 400 dynes*sec/cm5

What type of shock does the patient MOST likely have?

Answer 7

Distributive shock
The type of circulatory shock can be determined using hemodynamic variables. Distributive shock presents with a decreased SVR and an increased CI. CVP and PCWP will remain the same or decrease.

Question 8

A 78-year-old man with no significant past medical history is undergoing inguinal hernia repair when ST depressions are seen on the ECG rhythm. Which of the following is MOST likely true in an elderly patient undergoing surgery as compared to a younger patient?

Answer 8

Increased baseline sympathetic activity
Elderly patients have a decrease in parasympathetic tone and increase in sympathetic tone at rest. Other cardiovascular changes occurring in the elderly include a reduction in ischemic preconditioning and worsening diastolic dysfunction with increased left atrial pressures. Systolic function is often preserved in the otherwise healthy elderly patient.

Question 9

When used alone, which of the following leads is the MOST SENSITIVE for detecting myocardial ischemia?

Answer 9

V5
Intraoperative monitoring of Leads II and V4 is the preferred lead combination as it allows for rhythm monitoring and is sensitive for myocardial ischemia. Alone, V5 has the highest sensitivity for myocardial ischemia, however, this is not recommended for intraoperative monitoring.

Question 10

Which of the following coincides with the c-wave on central venous pressure waveform?

Answer 10

QRS wave on ECG
The QRS complex on the ECG correlates with the c-wave on the CVP waveform, mitral valve closure, and the beginning of aortic valve opening with an increase in ventricular pressure. The end of the T wave on the ECG correlates with the v-wave on the CVP waveform, aortic valve closure, and the beginning of mitral valve opening with a decrease in ventricular pressure.
Cannon a-wave is seen with AV dissociation. Large cv-wave is seen with tricuspid regurgitation. Large a-wave (different from cannon a-wave) is seen with tricuspid stenosis.

Question 11

You are called to the bedside for a patient who is acutely hypotensive and hypoxic. You suspect a pulmonary embolism. What is the IMMEDIATE first step in treatment?

Answer 11

Supportive therapy
In a hypotensive and hypoxic patient with a PE, stabilization is key. After initiation of supportive therapy, the PE can be treated. Inferior vena cava filter placement, thrombolysis, and systemic anticoagulation all play a role in PE treatment.

Question 12

Which of the following cardiovascular effects results from acute normovolemic hemodilution?

Answer 12

Increase stroke volume
In acute normovolemic hemodilution, there is an increase in cardiac output secondary to an increase in heart rate and stroke volume (increased preload and decreased afterload). Blood viscosity decreases, leading to a decrease in shear stress in the microvasculature increasing flow and venous return to the heart (increasing preload). The tissue hypoxia and acidosis cause arteriolar vasodilation (increased nitric oxide release from endothelial cells), adding to additional reductions in afterload.

Question 13

Which of the following is MOST appropriate for hemodynamic management of a patient with severe mitral regurgitation?

Answer 13

Maintain an increased heart rate
Goals of hemodynamic management in patients with severe MR include maintaining a normal to high heart rate, relatively low afterload (SVR), avoidance of increases in preload, and conditions that cause pulmonary vasoconstriction.

Question 14

Ongoing bleeding after cardiopulmonary bypass, despite appropriate protamine dosing that was confirmed with a normalized activated clotting time (ACT), should be initially managed with which of the following?

Answer 14

Platelets
After appropriate reversal of heparin with protamine, treatment of coagulopathy after CPB should begin with platelet transfusion.

Question 15

Activation of the body’s inflammatory system is the primary mechanism of which of the following embolic syndromes?

Answer 15

Aminotic fluid embolism
Of the classically described embolic syndromes, the etiology of pulmonary thromboembolism and venous air embolism is one of mechanical obstruction with the lungs and heart respectively. The etiology of fat embolism syndrome is primarily mechanical clogging of capillaries in the end organs of the body by fat droplets and bone marrow debris that is showered into the circulation during a bony trauma. The etiology of an amniotic fluid embolism syndrome is primarily the vasoactive and coagulopathic response to factors that are present in amniotic fluid that is forced into systemic circulation during a disorderly labor process.

Question 16

In which patient would placement of a permanent pacemaker be indicated?

Answer 16

Asymptomatic second degree AV Block type 2
Pacemaker placement is indicated for second-degree (type II) AV block, third-degree AV block, any symptomatic bradyarrhythmia, and refractory supraventricular tachyarrhythmias.

Question 17

A patient with a recent heart transplant presents develops the following vital signs while under general anesthesia for a procedure unrelated to the heart transplant:

HR: 32 bpm
BP: 84/34 mm Hg
ETCO2: 24 mm Hg
SpO2 95%

Of the following options, which is the MOST appropriate at this time?

Answer 17

Isoproterenol
Transplanted hearts are denervated and respond to direct acting agents (e.g. isoproterenol) but not vagal stimulation.

Question 18

Which of the following patients would benefit from an early invasive interventional cardiology procedure as opposed to initial conservative medical therapy?

Answer 18

55yr old with severe MR, peripheral edema and orthopnea
Early invasive strategies in high-risk patients result in a decreased risk of death or MI at 6 months as compared to conservative medical therapy. Risk factors include ischemia at rest, elevated biomarkers, new ST-segment depression, worsening heart failure or mitral regurgitation, low EF, VT, hemodynamic instability, recent PCI, and prior CABG.

Question 19

Which of the following is TRUE regarding intraoperative neuromonitoring (IONM) during aortic surgery?

Answer 19

loss of cortical nerve potentials from tibial nerve stimulation implies spinal cord ischemia during aortic repair
Intraoperative neuromonitoring (IONM) using motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) can be useful adjuncts for detecting spinal cord ischemia during some types of aortic surgery. The tibial nerve is the most common nerve utilized when monitoring for anterior and posterior spinal cord ischemia and cerebral hypoperfusion during these procedures. Some types of aortic surgery, particularly open TAAA repairs, do not commonly use IONM for spinal cord ischemia monitoring because they will not change clinical management of the patient.

Question 20

A 78-year-old male is successfully weaned off cardiopulmonary bypass and protamine is administered to reverse the effects of heparin. What hemodynamic changes would you expect to see with a reaction mediated by thromboxane A2?

Answer 20

low BP, LOW CO, LOW LVEDP, high PAP
Protamine is used to reverse the effects of heparin-induced coagulopathy, however, its use and side effects should always be considered when administering. Epinephrine is a useful medication for most reaction. In a type III protamine reaction, mediated by thromboxane A2, systemic hypotension is typically seen with right heart failure.

Question 21

For which of the following patients is preoperative beta-blocker therapy most likely indicated?

Answer 21

69yr M with HTN, DM, HLC]D, CKD, COPD coming for fem-pop bypass surgery
The ACC/AHA 2014 guidelines recommend that patients on beta-blockers should have them continued through the perioperative period. Patients with 3 or more risk factors for coronary artery disease may also benefit from beta-blocker therapy preoperatively.

Question 22

Which of the following cardiovascular components increases with aging?

Answer 22

Baseline sympathetic output
Cardiovascular changes that occur with aging include decreased responsiveness to α and β-stimulation; increase in sympathetic activity; decrease in parasympathetic activity; stiffening of the myocardium, arteries, and veins; conduction changes caused by myocardial fibrosis; and defective ischemic preconditioning.

TrueLearn Insight: Pulmonary changes that occur with aging primarily result from the increased stiffness of the chest wall and decreased stiffness of the lung parenchyma. The diaphragm flattens, and the thorax becomes barrel-shaped. The decreased curvature of the diaphragm leads to a worsening ability to generate negative pressure in the intrapleural space. The work of breathing increases with the flattened diaphragm and stiffened chest wall. Elastin is lost with age, and the lung tissue becomes less stiff, making it easier to inflate but also resulting an increased tendency to collapse, resulting in an increase in closing capacity with age. Other changes include a decreased response to hypercapnia and hypoxia, increased risk of upper airway obstructions due to loss of muscle mass in the hypopharyngeal and genioglossus muscles, impaired swallowing, and decreased coughing ability.

Question 23

Which of the following changes in the cardiovascular system would be expected as a result of aging?

Answer 23

Increased afterload
Cardiovascular changes in older patients include a decrease in arterial elasticity, vascular and myocardial compliance, autonomic responsiveness, and valvular calcification. Clinical manifestations of these changes include lower basal and maximal heart rate, decreased ability to compensate for hemodynamic changes, decreased responsiveness to adrenergic agonists, and propensity for arrhythmias.

Question 24

A 68-year-old man is undergoing an ascending aortic aneurysm repair under deep hypothermic circulatory arrest. During the rewarming phase of cardiopulmonary bypass, you notice the temperature monitors read slightly different values. Which of the following temperature monitoring sites would demonstrate the LARGEST discrepancy with cerebral temperature.

Answer 24

Bladder
Hypothermia is often used for cerebral protection during cardiopulmonary bypass. However, it is important to be aware of limitations of specific temperature monitoring sites. During dynamic temperature changes, bladder temperature will most significantly underestimate cerebral temperature.

Question 25

What is the cardiac output if the following variables are given?

Arterial oxygen saturation: 100%
Mixed venous oxygen saturation: 70%
Hemoglobin concentration: 10 g/dL
Oxygen consumption: 200 mL/min

Answer 25

5L
cardiac output (CO) is via the Fick principle, which states that the total uptake of oxygen (oxygen consumption [VO2]) is equal to the product of CO and the arterial oxygen content (Ca) − venous oxygen content (Cv) difference: CO = VO2 / (Ca − Cv).
The arteriovenous difference can be calculated by the following: 1.34 mL O2/g of hemoglobin × 10 × hemoglobin concentration × (arterial oxygen saturation − mixed venous oxygen saturation) = 1.34 mL O2/g of hemoglobin × 10 × 10 grams per L × (100%-70%) = 40 mL O2 per liter.

When oxygen consumption and the arteriovenous difference are inserted into the Fick equation, CO = (200 mL O2/min) / (40 mL O2/L) = 5 L/min.

Question 26

Which of the following statements is most TRUE regarding anesthetic considerations for minimally invasive direct coronary artery bypass (MIDCAB), as compared to traditional coronary artery bypass grafting (CABG)?

Answer 26

Potential for one lung ventilation
Considerations specific for MIDCAB: external defibrillation pads, thoracotomy incision, limited surgical exposure, no CPB (avoids deleterious effects), no cardioplegia, requires anticoagulation, no antifibrinolytics, typically LIMA to LAD, possible need for one lung ventilation or pharmacologic bradycardia, and possible hypotension during ligation of a coronary artery.

TrueLearn Insight: Postoperative pain after MIDCAB as compared to traditional CABG is controversial. Originally, avoiding full sternotomy was thought to result in less pain, but recent studies have shown increased post-operative pain with thoracotomy incision and rib spreading. Regional anesthesia to decrease post-operative pain and facilitate early-extubation or “fast-track” cardiac anesthesia may or may not include a thoracic epidural, paravertebral blocks, or intercostal rib blocks.

Question 27

A 74-year-old man is scheduled for an elective total hip arthroplasty. The patient had a myocardial infarction requiring drug-eluting stent placement two weeks prior and began taking aspirin and clopidogrel. Which of the following is MOST true in regard to the minimum time between drug-eluting stent placement and this patient’s hip arthroplasty?

Answer 27

reschedule the surgery for 6 months after the stent placement
For elective surgery after placement of a drug-eluting stent, surgery should be postponed for a minimum of 6 months after the time of stent placement.

Question 28

A 26-year-old man presents for elective endoscopic sinus surgery. He has a history of congenital long QT syndrome that was diagnosed after an episode of syncope. He has appropriately been cared for by a cardiologist who has prescribed a chronic medication for his long QT syndrome and has deemed that he is at an acceptable risk level for his current operation. Which of the following medications is MOST likely to reduce his risk of cardiac events?

Answer 28

Propranolol
The first-line therapy for reducing the risk of fatal cardiac events in congenital long QT syndrome is a beta blocker. Propranolol is the beta blocker of choice for the indication in this question. Conversely, beta blockers are often avoided in patients with acquired long QT syndrome because bradycardia can prolong the QT interval.

Question 29

Which of the following pacemaker codes denotes a pacemaker that paces the atria and ventricles without sensing their activity?

Answer 29

DOO
Pacemaker nomenclature consists of 3 to 5 positions. Position I indicates the chambers paced, II is the chambers sensed, III is the action taken by the pacemaker to a sensed event, IV is rate modulation, and V is multisite pacing. When only 3 positions are used, the last 2 positions are assumed to be O, which is none.

TrueLearn Insight: Pacemaker syndrome is commonly seen in VVI in which the ventricles are paced and sensed, and output is inhibited when an event is sensed. There is no atrial sensing to guide the ventricle; thus, the ventricle will contract at the programmed rate despite the rate of atrial contraction. As a result, there is loss of atrioventricular synchrony, which can lead to a loss of cardiac output. Patients will typically feel worse after the placement of the pacemaker.

Question 30

Which of the following statements regarding extracorporeal membrane oxygenation (ECMO) is TRUE?

Answer 30

One disadvantage of centrifugal pumps is the risk of thrombi
ECMO is used for cardiopulmonary support in patients with organ failure. It can be considered a modified CPB circuit.
When cardiorespiratory support is required, V-A ECMO should be used. V-V ECMO is useful when there is only respiratory failure.

Question 31

Which of the following statements is true regarding vasopressin compared to epinephrine?

Answer 31

Vasopressin is associated with decreased platelet concentration
Vasopressin stimulates water retention and peripheral vasoconstriction while improving MAP and cerebral and coronary perfusion. Vasopressin dramatically increases SVR and afterload which potentially reduces CO.

Question 32

A 54-year-old man with severe mitral regurgitation and coronary artery disease presents for mitral valve repair and coronary artery bypass grafting. Which of the following is MOST TRUE regarding this patient’s hemodynamic goals during the maintenance of cardiopulmonary bypass?

Answer 32

Venous oxygen saturation should be greater than 65
During cardiopulmonary bypass (CPB), optimal hemodynamic goals include a pump blood flow of around 1.6 to 3 L/min/m^2, an arterial blood pressure of around 50 to 90 mmHg, and an oxygen saturation in the venous cannula of greater than 65%. Mean arterial pressure (MAP) below 50 mmHg should generally be avoided.

Question 33

A patient is undergoing cardiac catheterization for acute heart failure in the setting of increased troponins and chest pain. Catheterization reveals severe left main coronary disease and the patient is scheduled for coronary artery bypass grafting. As a temporizing measure before surgery, an intra-aortic balloon pump (IABP) is placed. The IABP helium balloon should remain inflated during which part of the cardiac cycle?

Answer 33

Early diastole to late diastole
Intra-aortic balloon pumps (IABP) are used to augment cardiac output. When used properly (inflation in early diastole and deflation in late diastole) IABP will improve systemic mean arterial pressure (MAP) and coronary perfusion pressure.

Question 34

A 4-year-old male is undergoing surgical closure of a patent ductus arteriosus through a left thoracotomy incision. What structure has a high risk of injury during this procedure due to its anatomical proximity to the repair site?

Answer 34

Cranial nerve X
Due to its anatomical location, recurrent laryngeal nerve injury can occur during surgical repair of a patent ductus arteriosus.

Answer 35

Decrease HR from 90 to 60
Myocardial oxygen supply is determined by the arterial oxygen content of blood and coronary perfusion time and pressure. Myocardial oxygen demand is determined by myocardial work which is primarily dependent on heart rate and wall tension. Heart rate is a unique variable in that it plays a role in determining both myocardial oxygen supply and demand.

TrueLearn Insight: The left ventricle is perfused only during diastole. The right ventricle is perfused throughout the cardiac cycle but receives its greatest perfusion during peak/late systole and early diastole.

Question 36

A 4-year-old male is undergoing surgical closure of a patent ductus arteriosus through a left thoracotomy incision. What structure has a high risk of injury during this procedure due to its anatomical proximity to the repair site?

Answer 36

Cranial nerve X
Due to its anatomical location, recurrent laryngeal nerve (A) injury can occur during surgical repair of a patent ductus arteriosus. The recurrent laryngeal nerve is a branch of the vagus (CN X).

Question 37

Which of the following will improve myocardial oxygen supply and decrease myocardial oxygen demand?

Answer 37

Decrease the HR from 90 to 60
Myocardial oxygen supply is determined by the arterial oxygen content of blood and coronary perfusion time and pressure. Myocardial oxygen demand is determined by myocardial work which is primarily dependent on heart rate and wall tension. Heart rate is a unique variable in that it plays a role in determining both myocardial oxygen supply and demand.

TrueLearn Insight: The left ventricle is perfused only during diastole. The right ventricle is perfused throughout the cardiac cycle but receives its greatest perfusion during peak/late systole and early diastole.

Question 38

A 71-year-old man is in the ICU five days after sternotomy for mitral valve replacement when he becomes hypotensive and nonresponsive. His bedside monitor displays a wide complex, irregular tachyarrhythmia, and no pulse is palpable. What is the MOST appropriate next step?

Answer 38

Defibrillation
Patients who experience cardiac arrest due to ventricular fibrillation after cardiac surgery should immediately receive defibrillation up to three times in succession prior to mechanical support (internal cardiac massage or external chest compressions). A repeat sternotomy with internal cardiac massage is preferred rather than external compressions within 10 days of sternotomy because of the risk of fatal complications with external compressions.

Question 39

Which of the following is MOST associated with hyperkalemia?

Answer 39

QRS Prolongation
The earliest and most striking electrocardiographic feature of hyperkalemia is peaked T waves. This is followed by a prolonging of the PR segment, flattening of P waves, prolongation of the QRS complex, AV nodal block, sinus bradycardia, and eventually asystole.

Question 40

A 56-year-old man with a history of 100% occlusive left anterior descending coronary artery disease is scheduled for a robot-assisted minimally invasive coronary artery bypass grafting (MIDCAB) surgery. Which of the following is MOST TRUE regarding robot-assisted thoracoscopic MIDCAB when compared to other thoracoscopic surgeries?

Answer 40

insuffulation of the hemithorax is required
Major anesthetic considerations that differentiate minimally invasive coronary artery bypass surgery from a traditional coronary artery bypass surgery performed via a median sternotomy include the need for one-lung ventilation, potential capnothorax, positioning, room layout issues, and the placement of multiple novel endovascular devices. Transesophageal echocardiography is vital for the safe performance of these procedures. One-lung ventilation is made more difficult by the need for thoracic insufflation, and the induced capnothorax could have potentially severe hemodynamic implications in a patient with a diseased heart.

Question 41

You have arrived to a patient’s hospital room to evaluate them prior to a bowel resection for small bowel obstruction. The patient is a 65-year-old woman with a history of hypertension, diabetes, obesity, gastroesophageal reflux, and obstructive sleep apnea. She states she often gets substernal chest pain, which is not associated with activity or change in position. The pain abates on its own. The pain has not changed in character and occurs once every few months at random times. She is able to climb a flight of steps at a moderate pace. She has not had this evaluated in the past and an ECG that was obtained during an episode showed normal sinus rhythm without abnormalities. Of the following options, which is her MOST likely diagnosis?

Answer 41

Esophageal spasm
Conditions which may mimic myocardial ischemia include pericarditis, esophageal spasm, and costochondritis. In general, pericarditis presents with sharp retrosternal pain which is exacerbated by deep breathing, coughing, or changes in body position. Costochondritis is typically exacerbated by chest wall movement or palpation. Esophageal spasm may most likely mimic ischemia because it may be alleviated by nitroglycerin. It typically presents with severe substernal pressure which occurs at variable times.

Question 42

For which of the following patients with aortic stenosis (AS) is transcatheter aortic valve repair (TAVR) MOST appropriate?

Answer 42

89yr M with DM, HTN, Obesity, CRD and symptomatic severe AS
A candidate for TAVR must have symptomatic AS and be high surgical risk with expected survival greater than 12 months.

Question 43

Which of the following electrocardiographic findings is MOST likely to be observed in a patient with classic Brugada syndrome?

Answer 43

Pseudo right bundle branch block
Brugada syndrome is caused by a defect in a myocardial sodium channel and is manifested on ECG by a pseudo-right bundle branch block and ST elevations in V1-V3. Because malignant arrhythmias may occur, perioperative considerations include avoidance of sodium channel-blocking drugs and close ECG monitoring with resuscitation and defibrillation equipment readily available.

Question 44

A 28-year-old man presents to the operating room after having received 2 gunshot wounds to the abdomen. He is initially hypotensive and is resuscitated to normovolemia with 4 L of lactated Ringer’s solution. Which of the following effects is a DIRECT consequence of the hemodilution caused by resuscitation with crystalloid as opposed to with blood products?

Answer 44

increased CO and decreased SVR
Isovolemic hemodilution causes increased cardiac output, decreased systemic vascular resistance, and increased oxygen extraction.

Question 45

Which of the following findings, when measured during the preoperative evaluation for lung resection surgery, is associated with improved outcomes?

Answer 45

Predicted postoperative DLCO that is 50% of predicted
Predicted post operative (PPO) DLCO < 40% is the strongest single predictor of risk of complications and mortality following lung resection

Question 46

A 67-year-old man with congestive heart failure who is currently on a diuretic is prescribed another medication for treatment. After several days, he begins to experience nausea, vomiting, and abdominal pain. An electrocardiogram reveals downsloping ST-segment depressions. Two sets of troponins are negative. Which of the following medications was this patient MOST likely prescribed that resulted in these symptoms?

Answer 46

Digoxin
Digoxin toxicity can result from an overdose, hypokalemia, renal failure, or volume depletion. Symptoms include nausea, vomiting, diarrhea, anorexia, xanthopsia, blurry vision, disorientation, and weakness. Digoxin is also proarrhythmic, especially at supratherapeutic doses, resulting in ventricular tachyarrhythmias and atrial tachycardia with atrioventricular block as levels of digoxin increase.

TrueLearn Insight: The effects of digoxin revealed by electrocardiogram are a result of therapeutic doses of digoxin and are not necessarily markers of toxicity. The atrial and ventricular refractory periods are shortened, producing a shortened QT interval. The repolarization abnormalities result in the downsloping (scooping) ST-segment depression and T-wave flattening. The prolonged PR interval is a result of the increased vagal effects at the atrioventricular node.

Question 47

A 65-year-old man with a history of insulin-dependent type 2 diabetes mellitus, coronary artery disease with remote stent placement, stage 4 chronic kidney disease, and debilitating knee osteoarthritis that severely limits his daily activity presents to the preoperative anesthesia clinic before his scheduled open cholecystectomy for recurrent cholecystitis that is not amenable to a laparoscopic approach. The patient states he has been experiencing more shortness of breath over the past several months, and laboratory evaluation reveals a chronically elevated creatinine level of 2.2 mg/dL. Which of the following is the MOST appropriate next step?

Answer 47

Dobutamine Stress Echo
Preoperative cardiac risk assessment involves approaching patients in a stepwise fashion that focuses on the requirement for an emergent procedure, ruling out acute coronary syndromes, evaluating the risk of the actual procedure, and assessing the patient’s cardiac risk factors and functional status. In patients with multiple cardiac risk factors undergoing a high-risk surgical procedure who have a low/indeterminant functional capacity, a stress test is indicated.

TrueLearn Insight: There are many risk calculators that are helpful in determining patient and surgical risk factors for major adverse cardiac events. These include the Revised Cardiac Risk Index Calculator, the American College of Surgeons Surgical Risk Calculator, and the Myocardial Infarction or Cardiac Arrest Calculator. The 2014 American College of Cardiology and American Heart Association Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery also contains evidence-based recommendations.

Question 48

Which of the following BEST explains why etomidate may be administered for intravenous induction in patients with hypertrophic obstructive cardiomyopathy?

Answer 48

Preserved systemic vascular resistance
The goals of anesthetic management of HOCM include: (1) reduced myocardial contractility, (2) maintenance of (or increase in) of SVR, and (3) increased preload and cardiac output. Etomidate is a good choice for intravenous induction in patients with HOCM given its ability to maintain or increase SVR.

Question 49

A 53-year-old man with a history of hypertension, moderate coronary artery disease, moderate aortic stenosis, and insulin-dependent type 2 diabetes undergoes total knee arthroplasty under spinal anesthesia. Throughout recovery, he is noted to be persistently hypertensive with systolic blood pressures around 180 mmHg. When asked he states that his systolic blood pressure is typically around 130 mmHg, but he did not take his lisinopril or hydrochlorothiazide that morning. The administration of the following medications would be MOST LIKELY to cause cardiac injury in this patient?

Answer 49

Hydralazine
Hydralazine is a direct-acting alpha-receptor antagonist that is long-acting is administered in bolus doses. Its administration results in decreased systemic blood pressure and reflex tachycardia, both of which serve to increase the risk of cardiac injury in a patient with chronic hypertension. Labetalol is more commonly used to manage postoperative hypertension.

Question 50

A 45-year-old man is undergoing aortic valve replacement for aortic stenosis of a bicuspid aortic valve. As the patient is coming off cardiopulmonary bypass he becomes severely hypotensive. The surgeon notes the left ventricle is distended. Transesophageal echocardiogram examination reveals good right ventricular function and a mildly distended left ventricle with new lateral wall akinesis. Which of the following is MOST likely responsible for this patient’s hypotension?

Answer 50

Embolism in the left circumflex artery
Following cardiopulmonary bypass (CPB), especially with an open heart for valve surgery, there is a risk of coronary embolism. The right coronary artery is positioned to be more susceptible to embolism; however, embolism of any coronary artery is possible. Segmental wall motion abnormalities correlating to coronary artery distribution seen on transesophageal echocardiogram can be very helpful in determining the etiology of hypotension after CPB. Hypokinesis suggests coronary artery occlusion as a cause. Adequate wall movement or hyperkinesis with low SVR and resistance to cardioactive medications suggests vasoplegic syndrome.

Question 51

A patient with myxomatous disease develops acute mitral regurgitation after spontaneous chordae tendineae rupture. The patient is normotensive and is developing pulmonary edema. Which of the following is the MOST appropriate next step in management?

Answer 51

Sodium nitroprusside
Temporizing measures to decrease regurgitant flows in acute mitral regurgitation include arterial vasodilators (eg, nitroprusside), inotropic agents when contractility is impaired, and mechanical assist devices (ie, intra-aortic balloon pump or left ventricular assist devices).

TrueLearn Insight: Management of mitral regurgitation is “fast, full, forward” for maintaining a normal to fast heart rate, adequate to full preload, and reduced afterload (forward flow).