PASS MACHINE

Question 1

1. Most significant preoperative risk factors that predict postoperative cognitive impairment
2. Intraoperative risk factors that predict postoperative cognitive impairment

Answer 1

1. Advancing age (older than 70 years), preoperative cognitive impairment, decreased functional status, alcohol abuse, and a previous history of delirium.
2. Surgical blood loss, hematocrit less than 30%, and the number of intraoperative blood transfusions.

Factors that have not been shown to increase the risk of postoperative delirium or postoperative cognitive dysfunction (POCD)in adults include intraoperative hemodynamic derangements (hypotension), the administration of nitrous oxide, and the anesthetic technique (general versus regional).

Question 2

A 50-year-old patient develops stridor and difficulty breathing upon extubation after a complicated total thyroidectomy. The surgical site is seen to be normal. Which of the following is the most likely etiology of the patient’s presentation?

Answer 2

Bilateral recurrent laryngeal nerve injury

The recurrent laryngeal nerve innervates all the muscles of the larynx except for the cricothyroid. Unilateral damage to this nerve will result in hoarseness, but bilateral damage will result in respiratory distress. Visualization of the vocal cords will show a paramedian position of the cords. Bilateral superior laryngeal nerve injury (external branch) is incorrect as that will only result in hoarseness, whereas unilateral damage will have minimal effect on the voice. Bilateral superior laryngeal nerve injury (internal branch) is incorrect as that will not result in stridor and dyspnea as it must be noted that the internal branch is sensory. Hematoma is incorrect as that results within the first few hours after surgery (generally within 6-24 hours). Also, this patient is not presenting with any signs of a hematoma.

Question 3

1. Largest cause of mortality in obese patients receiving liposuction?
2. What about during Abdominoplasty?
3. What concentration of lidocaine is used for tumulscent liposuction?

Answer 3

1. Pulmonary Embolism
   
   1. Liposuction and abdominoplasty when combined have a high risk for deep vein thrombosis. Some people believe that during liposuction, every patient suffers from some degree of fat embolization / shower phenomenon.
   2. Patients at increased risk are those greater than 40 years old, surgery duration greater than 30 minutes, malignancy, immobilization, hypercoagulable states, and obesity. In patients at higher risk, deep vein thrombosis chemoprophylaxis with low molecular weight is indicated.
2. Deep Vein Thrombosis
   
   1. Abdominoplasty has the highest published rates of deep vein thrombosis and pulmonary embolus in plastic surgery.
3. Tumescent anesthesia often uses 0.05% and 0.1% lidocaine to prevent local anesthetic systemic toxicity.

Question 4

True or False: The Sensory component of the trigeminal nerve is combined in the gasserian ganglion

Answer 4

TRUE

The sensory component of the trigeminal nerve is combined in the gasserian ganglion. The sensory innervation of the face is under the dependence of the trigeminal nerve associated with the C2-C4 cervical nerve roots that constitute the superficial cervical plexus. The trigeminal nerve provides sensory and motor components. The sensory component is combined in the trigeminal ganglion, also known as the semilunar or gasserian ganglion. This ganglion lies in the Meckel cave, an invagination of the dura mater near the apex of the petrous part of the temporal bone in the posterior cranial fossa. Postganglionic fibers exit this ganglion to form three nerves: the ophthalmic nerve, the maxillary nerve, and the mandibular nerve. The ophthalmic nerve innervates the forehead, eyebrows, upper eyelids, and anterior area of the nose. The maxillary nerve innervates the lower eyelid, upper lip, lateral portion of the nose and nasal septum, cheek, roof of the mouth, bone, teeth, sinus of the maxilla, and soft and hard palates. The mandibular nerve provides nerve supply to the anterior two-thirds of the tongue and the skin, mucosa, teeth, and the bone of the mandible.

Question 5

Patient presents for elective surgery with the following EKG. Patient is a highly athletic marathon runner. What is the next step in management?

Answer 5

Patient has 1st degree heart block; prolonged PR d/t high vagal tone at resting heart rate.

First-degree AV block is common amongst highly conditioned athletes due to increased vagal tone and a lower heart rate. However, a 24-hour Holter, option A, is appropriate to prove that this rhythm disappears during exercise and/or hyperventilation.

Question 6

What is the correct Miller Laryngoscope Blade Size for the following patients:

1. Premature
2. Full term Infant
3. 1 year old child
4. 2 year old
5. 6 year old
6. 10 year old
7. 18 year old

Answer 6

Unlike laryngeal mask airways, the choice of laryngoscope blade size is based on age and not on weight.

1. A size 0 is recommended for premature infants.
2. A size 0-1 for full term infants
3. A size 1 for a 1-year-old child
4. A size 1-1.5 for a 2-year-old child
5. A size 1.5-2 for a 6-year-old child
6. A size 2-3 for a 10-year-old child
7. A size 3 for an 18 year old.

Question 7

A 43-year-old man is receiving a blood transfusion following colorectal surgery. Only 1-2 ml of ABO compatible, screened, crossmatched blood has dripped in when he develops dyspnea, bronchospasm, and hypotension occurs. His wife says that he has received a unit of blood before without any complications. Which diagnoses is most likely?

Answer 7

HEREDITARY IgA DEFICIENCY

A true anaphylactic reaction to a blood transfusion can occur during transfusion of crossmatched blood when the patient has a hereditary IgA deficiency. A prior transfusion and exposure to IgA antigens results in antibody formation and subsequent blood transfusion causes an anaphylactic reaction.

Question 8

During an infusion, how many half lives does it take to reach steady state??

Answer 8

4-5 half lives

During an infusion, it takes one half-life for the drug to reach 50% of steady-state concentration. It similarly takes 2 half-lives to reach 75%, 3 half-lives to reach 87.5%, and 5 half-lives to reach 97% of the steady-state concentration. By 4 to 5 half-lives, the patient is typically considered to be at steady state.

Question 9

1. Where is the superficial cervical plexus blocked?
2. The Deep Cervical Plexus?

Answer 9

1. The superficial cervical plexus is blocked at the midpoint of the posterior border of the sternocleidomastoid muscle.
2. The deep cervical plexus block is a paravertebral block of the C2 to C4 spinal nerves as they emerge from the foramina in the cervical vertebrae.

The prevertebral muscles receive branches from the cervical plexus. The cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which arise from C1 to C4 cervical segments in the neck. It is located in the neck, deep to the sternocleidomastoid muscle, and supplies branches to the prevertebral muscles, strap muscled of the neck, and the phrenic nerve.
The deep cervical plexus supplies the musculature of the neck segmentally and the cutaneous sensation of the skin between the trigeminally innervated face and the T2 dermatome of the trunk.
The cervical plexus is unique in that it divides early into cutaneous branches, penetrating the cervical fascia and deeper muscular branches that innervate the muscles and joints, which can be blocked separately.

Question 10

Identify the following pressure volume loops

Answer 10

Question 11

What is difference between adult and newborn lumbar spine?

1. What is the conus medullaris?
2. What is the filum terminale?
3. Termination of dural sac?

Answer 11

1. Conus medularis is the termination of the Spinal Cord
   
   1. L2 in Adults; L3 in Newborn
2. Conus medularis continues as filum terminale attaches at coccygeal ligament
3. Adult Dural Sac Terminates at S2 vs Newborn at S3

Question 12

Your anesthetic is delivered via a normal sevoflurane variable bypass vaporizer. Temperature of room increases to 80 degrees. What affect will this have on the amount of oxygen being diverted into the vaporizing chamber of your sevoflurane vaporizer?

Answer 12

• The rise in temperature will result in more sevoflurane evaporating inside the vaporizer (just as, if the temperature of a pot of water increases, more water will evaporate and go into the vapor phase). If there were no compensating mechanism inside the vaporizer, then this rise in temperature would result in higher delivered sevoflurane, which could result in a dangerous overdose of inhaled agent.
• Inside every variable bypass vaporizer is a temperature compensation valve. This temperature compensation valve will divert MORE oxygen into the vaporizing chamber if the temperature DROPS, but the temperature of the room did not drop in this case.
• The temperature compensation device in a variable bypass vaporizer diverts LESS oxygen into the vaporizing chamber when the ambient temperature RISES. That is, more sevoflurane is going into the vapor phase due to the rise in temperature, to compensate for this, the compensation device sends less oxygen into the vaporizing chamber to keep the output of sevoflurane constant.

Question 13

What drugs metabolized by the following enzyme

1. CYP 3A4
2. CYP2D6
3. CYP2C9
4. CYP2B6
5. CYP2C19

Answer 13

1. CYP 3A4: metabolizes (inactivates) acetaminophen, alfentanil, dexamethasone, fentanyl, lidocaine, methadone, midazolam, and sufentanil; partially propofol
2. CYP2D6: Converts codeine to morphine, Tramadol, Hydrocodone, Oxycodone
3. CYP2C9: Phenytoin, Warfarin, Ibuprofen, Losartan, and Glipizide.
4. CYP2B6: Propofol
5. CYP2C19: Clopidrogrel, proton pump inhibitors, such as omeprazole, and antidepressants

Question 14

Irreversible ischemia in patients occurs at what cerebral blood flow?

What is normal CBF?

Answer 14

• Normal global cerebral blood flow (CBF) is 50 mL/100 g/min.
• When CBF falls to 35 mL/ 100g/min, protein synthesis is neurons is stopped but the tissue can survive if the CBF doesn’t worsen.
• At 20 mL/100 g/min, the synaptic transmission between neurons is interrupted, disturbing the function of still viable neurons.
• AT 10 mL/100 g/min, irreversible cell death.

Question 15

When does peak serum level of lidocaine occur following injection of lidocaine for tumulscent anesthesia for liposuction?

Answer 15

• It has been shown that serum levels of lidocaine peak after 12 to 14 hours after tumescent anesthesia for liposuction has been used.

This technique involves the subcutaneous injection of large volumes of dilute lidocaine and epinephrine. The American Society of Plastic Surgeons guidelines recommends 35 mg/kg as the maximum dose of lidocaine that can be used for liposuction although doses up to 55 mg/kg have been used safely. These high doses pose a clinical concern as patients are at high risk for LAST which includes symptoms such as mental status changes, seizures, respiratory arrest, dysrhythmias, and cardiac arrest. It is not uncommon for surgical centers to discharge patients home after these procedures and prior to the peak serum lidocaine level. This practice carries the risk of leaving the patient unmonitored during period of increased risk.

Question 16

Which one of the following induction agents has been shown to produce convulsion-like EEG potentials in epileptic patients?

A. Propofol

B. Thiopental

C. Midazolam

D. Etomidate

E. Fentanyl

Answer 16

Etomidate has been shown to cause myoclonus as well as convulsion-like EEG potentials in patients with epilepsy or other seizure disorders. Despite this property, etomidate does have anticonvulsant properties and has been used to terminate status epilepticus. None of the other agents listed have been known to show convulsion-like EEG patterns. Ketamine and propofol may induce myoclonic and seizure-like activity in nonepileptic patients.

Question 17

1. Where do you inject local anesthetic for an ulnar nerve block at the wrist?
2. The Medial Nerve?
3. The Radial?

Answer 17

1. The ulnar nerve may anesthetized by injecting beneath the flexor carpi ulnaris tendon between the ulnar artery and pisiform bone.
2. Injecting between the flexor carpi radialis and palmaris longus tendons 2 to 3 cm proximal to the wrist crease will anesthetize the median nerve.
3. Placing local anesthetic superficial to the extensor pollicis longus tendon at the base of the first metacarpal following the tendon will anesthetize the radial nerve.

Question 18

Line isolation monitor will alarm when current exceeds what threshold?

Answer 18

5 miliamps

Prevents macroshock

Question 19

Revised Cariac risk Index Criteria

Answer 19

Question 20

CHADS2VASC Criteria

Answer 20

Score for for Atrial Fibrillation Stroke Risk calculates stroke risk for patients with atrial fibrillation

Max Score is 9

0 = Low Risk, no need for AC

1 = Low - consider oral AC or Aspirin

2 = High Risk, Consider oral AC

Question 21

Hyperventilation affects cerebral blood flow for what duration of time?

Answer 21

24 hours

Hyperventilation causes a decrease in the PaCO2 levels which then leads to vasoconstriction of cerebral vasculature thereby causing a reduction in the cerebral blood flow and intracranial pressure. Carbon dioxide (CO2) crosses the blood-brain barrier where it alters the extracellular pH leading to either vasodilatation or vasoconstriction, depending on the pH level. Because of this, respiratory acidosis markedly affects the cerebral blood flow as compared with metabolic acidosis since hydrogen ions do not cross the blood-brain barrier.
Immediately during hyperventilation, cerebral blood flow begins to decrease, and it continues to decrease until PaCO2 level reaches 30 mmHg.
Beyond this level, the effect stabilizes, and after 24-48 hours, any change in PaCO2 will no longer change the cerebral blood flow and intracranial pressure because of the buffering effect of alkalotic cerebrospinal fluid. Acute hyperventilation may lead to a significant decrease in the cerebral blood flow that may cause cerebral ischemia.

Question 22

The most labile factor in plasma is what?

Answer 22

Factor 8

Question 23

A surgical patient presents with a history of a “heart problem” their doctor told them about, but they state it has never been an issue and they have good exercise tolerance. About halfway through his open small bowel resection surgery, the patient’s blood pressure begins to decline. There is no ongoing hemorrhage. A bolus of epinephrine is given, but it does not rectify the problem. Next, a bolus of esmolol is administered with resolution of the hypotension. Which of the following is the most likely “heart problem” this patient has?

Answer 23

Hypertrophic Obstructive Cardiomyopathy

It causes a dynamic obstruction of the left ventricular outflow tract. Increasing contractility worsens the dynamic obstruction while decreasing the contractility with beta-blockade usually shows improvement. Although it is beneficial to slow heart rate in the setting of aortic stenosis, the most common drug that improves cardiac stability with this lesion is phenylephrine.

Question 24

Between what layers is local anesthesia deposited for a TAP block in the following image?

Answer 24

C

Transverse Abdominis and Internal Oblique

“TI the TAP”

Question 25

Which fluid can interfere with blood transfusion cross-match?

Answer 25

Dextran

Dextran 40 is a colloid used in vascular surgery with the potential benefit of reducing the risk of thrombosis as it inhibits platelet aggregation. One of its side effects, however, is rouleaux formation which can affect cross-matching of blood. If used, it is recommended to obtain a blood sample for cross-matching prior to administration.

Question 26

Identify the following conditions

Answer 26

Question 27

The typical dosage rate used for insulin infusion?

Answer 27

Typically the rate that is used is 0.02 units/kg/hour, which would be 1.6 units/hour for a patient weighing 80 kg.

Question 28

Multiple repeated attempts at central line placement in a trauma patient result in respiratory compromise. Needle decompression of the chest and thoracentesis results in the extraction of the pleural fluid shown in the image below: Which of the following central line location attempts most likely caused this complication?

Answer 28

• “Left subclavian vein” is correct because the thoracic duct has unintentionally trespassed and it is near the L subclavian vein.

Question 29

True or False: Phantom limb pain is often reactivated with neuraxial anesthesia

Answer 29

TRUE

Question 30

What live enzyme converts Clopidrogrel to its active form?

Answer 30

CYP2C19

Question 31

A 45-year-old man enters the hospital with vague complaints of chest pain. His examining physicians are considering whether to do cardiac catheterization (considered the gold standard for diagnosing coronary atherosclerosis) or perform the less invasive coronary CT scan. To determine the best approach to managing this patient, his doctors will review the literature to see how the newer, less invasive method of diagnosis compares with the older, more invasive method. Which of the following is the best statistical method to determine how the new method measures up to the old standard?

A. Chi-square

B. Power analysis

C. Odds ratio

D. Bland-Altman plot

E. Wilcoxon rank sum test

Answer 31

Option A is incorrect because the Chi-square test is a statistical method used to see whether a set of observed data fit a hypothesis. A medical example of use of a Chi-square test is to compare the incidence of postoperative nausea and vomiting in a group of patients treated with ondansetron with a group of patients treated with acupressure.
Option B is incorrect because a power analysis is undertaken prior to conducting a study to see how many patients will need to be studied to draw meaningful conclusions. For example, if you are studying an extremely rare event (malignant hyperthermia), a power analysis will reveal that you need to study an enormous number of patients to draw any conclusions.
Option C is incorrect because odds ratio tells you the likelihood of an event occurring in one group versus the likelihood of an event occurring in a different group. For example, an odds ratio might look at the likelihood of black lung disease occurring in coal miners versus office workers.
Option D is correct because the Bland-Altman plot is the best way of comparing one technique with another. It is traditionally used to compare a “gold standard” method (here, cardiac catheterization) versus a new, as-yet-unproven method.
Option E is incorrect because the Wilcoxon Rank Sum Test is a non-parametric method for seeing whether two samples are derived from the same population. This does not compare two different methods.

Question 32

A patient undergoing an open colectomy requires extensive transfusion of blood products. Which of the following risks of transfusion is statistically most likely to occur?

A. Bacterial contamination

B. Transfusion-related lung injury (TRALI)

C. Anaphylaxis

D. Transmission of hepatitis B virus

Answer 32

“Bacterial contamination” is correct because bacteria are more commonly found in blood products (especially platelets) compared the risk of TRALI, anaphylaxis and Hep B.

Question 33

True or False: Hypotension following caudally administered local anesthetic is rare in children <10 due to the fact that the sympathetic nervous system is not completely mature yet.

Answer 33

TRUE

Question 34

A 25-year-old G1P0 female is hospitalized at 34 weeks gestational age for management of her preeclampsia. While reviewing her chart you note that she has been started on methyldopa, magnesium sulfate, and betamethasone. Her vitals were last checked 10 minutes ago and include a blood pressure of 122/68 mmHg and there are no signs of fetal distress. Her platelet count is 319,000/mm^3, AST is 79 IU/L, ALT is 88 IU/L, and Mg is 0.8 mg/dL. The patient suddenly starts seizing. Supplemental oxygen is started and the patient is placed in the lateral position. Which of the following medications is the best choice for both treating the current seizure and preventing further seizures from happening?

A. Magnesium sulfate

B. Calcium gluconate

C. Diazepam

D. Phenytoin

Answer 34

This question involves a patient who is having active eclamptic seizures. Magnesium sulfate (MgSO4) is the mainstay of treatment of seizures in eclampsia and for the prevention of progression of preeclampsia to eclampsia. The target range for magnesium therapy is 4.8 mg/dL to 8.4 mg/dL in these women. This patient’s serum magnesium is 0.8 mg/dL which is low. Option A the correct choice as this is the first-line medication used for both treatment and prevention of eclampsia-associated seizures.
Option B, calcium gluconate is an antidote used for magnesium toxicity. This patient’s magnesium is low so it would likely further exacerbate this patient’s condition and most certainly not improve it.
Diazepam, Option C, can be used to rapidly terminate a seizure if the patient is appropriately treated with magnesium sulfate. However, this patient is having her first seizure and her magnesium level is below the therapeutic target, making Option C incorrect.
Phenytoin, Option D, is an alternative drug for treating seizures but should not be used prior to trying magnesium sulfate and/or benzodiazepines first.

Question 35

Which one of the following changes describes the response of cerebral blood flow (CBF) to an increase in partial pressure of arterial carbon dioxide by 1 mmHg?

A. Increase by 6 cc/100 g/min

B. Increase by 1 cc/100 g/min

C. Increase by 2 cc/100 g/min

D. Decrease by 2 cc/100 g/min

E. Decrease by 1 cc/100 g/min

Answer 35

PaCO2 affects CBF by causing changes in CSF pH, which results in cerebral vasodilation in response to increased PaCO2. The vasodilation results in decreased resistance to blood flow and an increase in CBF. CBF increases (normal is 50 cc/100 g/min) by 1 cc/100 g/min for each 1 mmHg increase in PaCO2. Changes in temperature can cause a change in CBF by 6 cc/100 g/min. The percentage increase of CBF in response to PaCO2 is 2%. There is no decrease in CBF when PaCO2 is increased.

Question 36

A 53-year-old female taking opioids on a long-term basis for non-malignant pain is scheduled for an exploratory laparotomy. You decide to use morphine IV-PCA for her postoperative pain control and calculate her chronic opioid usage as 240 mg oral morphine equivalents per day. After converting this to 80 mg IV morphine equivalents (240 mg/3), you set the basal PCA rate at 3.3 mg per hour (80 mg/24 hours) to cover her chronic opioid usage. Which of the following would be the most appropriate initial setting for her intermittent bolus dose?

A. 0.5 to 1.5 mg every 10 minutes

B. 1.5 to 3.5 mg every 10 minutes

C. 1.5 to 3.5 mg every 20 minutes

D. 3.5 to 5 mg every 15 minutes

Answer 36

This case describes a patient receiving chronic opioids who requires additional analgesia for acute postoperative pain. IV-PCA analgesia is a very good option for this patient. While she is NPO, her preoperative opioid dosage can be continued as the basal PCA rate. The initial patient-controlled bolus dose is calculated as 50% to 100% of her preoperative hourly IV opioid dose, administered every 8 to 15 minutes. As her hourly IV morphine equivalent dose is 3.3 mg per hour, the appropriate initial IV morphine bolus dose would be 1.7 to 3.3 mg every 8 to 15 minutes. As such, Option B is the best answer. Of note, the aforementioned doses refer to just the initial PCA settings, and frequent reassessment will be required for this type of patient.

Question 37

You’re examining an 82-year-old male nursing home resident in the emergency department with ongoing lethargy. The patient’s past medical history is remarkable for Lewy Body Dementia. On arrival, his vitals are 89/56 mm Hg, pulse 102 beats per minute, respiratory rate 13 breaths per minute. The rest of the physical exam is unremarkable. Lab work reveals a serum sodium of 162 mEq/L, serum creatinine of 1.2 mg/dL, BUN of 42 mg/dL. The patient weighs 68kg. What is the approximate amount of fluid that should be given to this patient?

A. 5L

B. 3L

C. 1L

D. 7L

Answer 37

This case describes an elderly patient presenting with hypernatremia. These source of hypernatremia in a nursing home resident with dementia is usually secondary to inadequate free water intake. As such the hypernatremia needs to be corrected with replacement of the water. Fluid quantity is calculated according to the Free water deficit formula. Free water deficit (L) = TBW (patient’s body weight (kg) x 0.5 (women/older men)) x ((actual serum Na - ideal serum Na) / ideal serum Na). As such the formula equals 68 x 0.5 x (162-140)/140 and leads to a free water deficit of 5.34L, making option A the correct choice.

Question 38

Which of the following correctly statements regarding upper extremity nerves with respect to the axillary artery is correct?

A. Median nerve is superior to the artery

B. Ulnar nerve is posterior to the artery

C. Radial nerve is medial to the artery

D. Musculocutaneous nerve is lateral to the artery

Answer 38

Option A is correct because the median nerve is located superior to the axillary artery. “The ulnar nerve is medial and anterior to the axillary artery. The radial nerve is posterior to the axillary artery. The musculocutaneous nerve has already departed the brachial plexus sheath at the axillary level.

Question 39

After the administration of oxycodone for postoperative analgesia, a 24-year-old male reports feeling relaxed and happy. Which one of the following opioid receptors is most likely responsible for the observed effects?

A. Mu-1

B. Mu-2

C. Kappa

D. Delta

E. Sigma

Answer 39

This patient is exhibiting euphoria, which is a result of the activation of the mu-1 receptor. The kappa receptor is responsible for dysphoria and sedation. Mu-2 and delta have no euphoric or dysphoric effects.

Question 40

A difficult airway is encountered during induction of a 57-year-old female undergoing a lobectomy. Successful intubation with a double-lumen endotracheal tube is achieved on the third attempt. At the end of the case, the patient is extubated without incident; however, she develops stridor in the PACU 30 minutes later. Which one of the following statements is true regarding this patient?

A. This is most likely laryngospasm, and administration of succinylcholine is warranted

B. Arytenoid dislocation may have occurred contributing to airway obstruction

C. Prophylactic use of steroids should have been administered as it has been proven to prevent postextubation stridor

D. Positive pressure in the treatment of stridor is a third-line treatment

E. Warmed, humidified air, but not racemic epinephrine, should be used in the treatment of stridor

Answer 40

Laryngeal edema characteristically appears 30 minutes to 6 hours postoperatively and can be caused by obstruction in any area of the upper respiratory region from external compression (hematoma) and internal derangements (arytenoid dislocation) to edema and trauma. Laryngospasm is more likely to occur, immediately following extubation, rather than during this delayed circumstance. renotoxic agentsIn addition, first-line treatment consists of positive pressure. Other methods of treatment include warmed humidified air or racemic epinephrine; though, the physician should be aware of watching out for rebound stridor after the epinephrine wears off. Steroids here, as in so many other cases, are unproven but often used.

Question 41

A 29-year-old G1P0 parturient with myasthenia gravis (MG) presents at 37 weeks with preeclampsia, complaining of severe headache and blind spots in her vision. Her blood pressure on admission is 173/115 mmHg. Early in the pregnancy, the patient was hospitalized and intubated for a respiratory crisis. Which one of the following plans represents the most appropriate management?

A. Initiation of magnesium sulfate infusion for seizure prophylaxis awaiting surgical delivery at 38 weeks

B. Urgent surgical delivery after the induction of general anesthesia with propofol and rocuronium followed by endotracheal intubation

C. Urgent surgical delivery after epidural placement and slow incremental titration of local anesthetic to achieve a T4-T6 level

D. Immediate surgical delivery after an intrathecal injection of high dose local anesthetic

E. Expectant management in anticipation of spontaneous vaginal delivery to avoid the operative risk of Cesarean section

Answer 41

The anesthetic implications of MG and preeclampsia are both high yield board topics. MG is an autoimmune disorder characterized by muscle weakness and fatigue resulting from destruction of acetylcholine receptors at the neuromuscular junction by autoantibodies. A history of respiratory crisis suggests high severity of the disease, which is often worsened in pregnancy. Because magnesium produces muscle weakness by inhibiting acetylcholine release, it is contraindicated in patients with MG and has been reported to cause death in cases of severe MG. Expectant management is inappropriate given the risk to the patient of progression to eclampsia, especially in the setting of avoiding magnesium prophylaxis.
A neuraxial technique poses less risk to the patient than induction of general endotracheal anesthesia as it avoids the need to intubate a potentially difficult airway and the risk of stroke as a result of laryngoscopy induced hypertension. A slow titration of local anesthetic to achieve a surgical level is preferred to minimize the risk and extent of engendering further respiratory muscle weakness. The practitioner must nevertheless be prepared to escalate to general endotracheal anesthesia to support ventilation in the event of respiratory insufficiency/failure secondary to muscle weakness.

Question 42

Your elderly grandparents ask you which one of them will likely do better when they have their total knee arthroplasty (TKAs) at the same time so they can go to rehab together. Your grandmother has coronary artery disease (CAD) and heart failure (HF). Your grandfather has HF and atrial fibrillation (AF) but no CAD. 30-day mortality is the lowest in which group of patients?

A. Non-ischemic heart failure

B. Ischemic heart failure

C. Coronary artery disease

D. Atrial fibrillation

Answer 42

Coronary artery disease is correct because the average risk of a patient with CAD is only 2.9%.
Non-ischemic heart failure is incorrect because the average risk of a patient with non-ischemic HF is 9.3%.
Ischemic heart failure is incorrect because the average risk of a patient ischemic HF is 9.2%.
Atrial fibrillation is incorrect because the average risk of a patient with atrial fibrillation is 6.4%.

Question 43

A 29-year-old man presents for resection of an intracranial astrocytoma. He is otherwise healthy. Which of the following statements describes cerebral blood flow in this patient?

A. CBF autoregulation remains constant over a mean arterial blood pressure (MAP) range of 40 to 150 mm Hg

B. Hypoxemia reduces CBF

C. Cerebral blood flow (CBF) is tightly linked to cerebral metabolic rate (CMR). Propofol reduces CMR and induces a concomitant fall in CBF

D. Phenylephrine, by directly constricting cerebral blood vessels, reduces CBF

Answer 43

The brain has a high metabolic rate and commands about 15% of the total cardiac output. CBF is tightly linked to cerebral metabolism rate (CMR). If metabolism falls, local cerebral autoregulation responds by reducing blood flow. Almost all volatile anesthetic agents reduce CMR. Likewise, most intravenous agents (except for example ketamine) reduce CMR and thereby reduce CBF. SaveCBF is less tightly tied to systemic blood pressure, due to autoregulation, which allows CBF to remain constant over a wide range of blood pressure: a range in MAP from roughly 65 to 150 mm Hg results in little change in CBF. However, as MAP falls below 65 mm Hg, CBF falls in a linear fashion, and as MAP increases above 150 mm Hg, a similar linear increase in CBF occurs. Hypoxemia (PaO2 < 60 mm Hg) results in a dramatic increase in CBF. Vasopressors, such as phenylephrine, norepinephrine, ephedrine and dopamine do not have direct effects on the cerebral vasculature.

Question 44

A 35-year-old patient with chronic anxiety is in the post-anesthesia care unit following a hysteroscopy. The patient’s home medications include lorazepam and a multivitamin. The patient is anxious postoperatively, and her nurse is requesting the patient be given a benzodiazepine. What is the correct order of potency of the following benzodiazepines (from most to least potent)?

A. Diazepam, midazolam, lorazepam

B. Diazepam, lorazepam, midazolam

C. Lorazepam, diazepam, midazolam

D. Lorazepam, midazolam, diazepam

E. Midazolam, lorazepam, diazepam

Answer 44

The correct order of potency from greatest to least is lorazepam, midazolam, diazepam. The potency of a drug can also be described as its affinity for its respective receptor. Midazolam is as much as 6 times more potent than diazepam, while lorazepam is as much as 10 times more potent than diazepam.

Question 45

While examining a patient in the ICU who has been admitted for sepsis, you notice that the patient has a diastolic murmur followed by an opening snap. The patient is catheterized with a pulmonary artery catheter for ongoing monitoring of his hemodynamics, which are within normal limits. Which of the following waveforms would you expect to see on the pulmonary artery occlusion pressure (PAOP) monitor?

A. Large v waves

B. Large a waves

C. Discordant PAOP and LV end-diastolic pressure

D. Small a waves

Answer 45

This case describes a patient with a murmur most likely attributable to mitral stenosis. Physiologically, the pulmonary artery occlusion pressure (PAOP) tracing is similar to a right atrial waveform. The a wave reflects the contraction of atrial systole and the following x wave represents the subsequent fall in left atrial pressure. The v wave represents the ventricular systole and passive atrial filling in atrial diastole. Finally, the y descent reflects the fall in left atrial pressure following the opening of the mitral valve and the initiation of passive filling of the left ventricle.
Option A, large v waves, usually represents mitral regurgitation.
Option B, large a waves, is the correct choice. Large a waves can be seen with any cause that increases resistance to left ventricular filling such as mitral stenosis.
Option C, discordant PAOP and LV end-diastolic pressure is most likely seen due to aortic sufficiency or pulmonary disease.
Option D, small a waves, is most likely to lung zone misplacement of the pulmonary artery catheter as the PAOP may be overestimated if placed in West zone 1 or 2 of the lung.

Question 46

A 43-year-old patient complains of severe pain in the left leg for the last 4 months. The pain starts in the back and extends to the foot. It is associated with a tingling sensation and numbness and finds difficulty in walking due to that. The patient has found no improvement with medications and is now planned for a sciatic nerve block with nerve stimulation. During the procedure, plantarflexion of the foot is noted. Which of the following muscles is responsible for this as a result of the nerve stimulation?

A. Soleus

B. Rectus femoris

C. Semitendinosus

D. Gracilis

Answer 46

The desired motor response is plantarflexion and inversion of the foot due to tibial component of sciatic nerve or dorsiflexion and eversion of the foot due to common peroneal component. Plantarflexion involves soleus, gastrocnemius, and plantaris involvement among other muscles. Inversion of foot is due to the tibialis anterior. Dorsiflexion is associated with the tibialis anterior, fibularis, extensor digitorum and hallucis longus. Eversion is related to the fibularis longus, brevis and tertius.
Option A, the soleus, is correct as it is involved with plantarflexion which is a desired motor response to nerve stimulation for a sciatic nerve block.
Option B, rectus femoris, is incorrect because it is involved with extension of the knee joint.
Option C, semitendinosus, is part of a muscle group known as the hamstrings which extend the hip and flex the knee.
Option D, gracilis, is incorrect as it contributes to flexion at knee joint.

Question 47

A 70-year-old male presents for evaluation at the preoperative clinic. His pulse is noted to be particularly slow. Which one of the following dysrhythmias is an indication for a pacemaker?

A. 1st degree AV block

B. Mobitz type 1

C. Mobitz type 2

D. Right bundle branch block

E. Left bundle branch block

Answer 47

The correct answer is option C. Mobitz type 2 frequently progresses to 3rd-degree heart block and is an indication for a permanent pacemaker. The other conditions listed typically do not require a pacemaker to prevent syncope or other sequalae.

Question 48

A 33-year-old man presents with tachypnea, fatigue, diaphoresis, tachycardia, and confusion. His arterial blood gas reveals a pH of 7.33. His serum electrolytes are as follows: Sodium 137 mEq/L Chloride 108 mEq/L Bicarbonate 20 mEq/L Which of the following etiologies is consistent with this patient’s lab values?

A. Diarrhea

B. Methanol ingestion

C. Diabetic ketoacidosis

D. Uremia

Answer 48

The anion gap is the difference between primary cations like sodium and potassium and the primary anions like the chloride and the bicarbonate in the serum. It is usually done to differentiate potential causes for a patient’s metabolic acidosis. The formula for estimation of the anion gap is: anion gap = [Na+] - ([Cl-] + [HCO3-]). The typical normal values range from 8-12 mEq/L. When substituting the patient’s lab values, the anion gap is 9 mEq/L which is within the normal range. Some causes of normal anion gap metabolic acidosis include diarrhea, renal tubular acidosis, enteric or pancreatic fistula, chronic kidney disease, adrenal insufficiency, or medication. Elevated anion gap metabolic acidosis may be due to methanol, uremia, diabetic ketoacidosis, paraldehyde or phenformin ingestion, iron or isoniazid ingestion, lactic acidosis, ethylene glycol, and salicylate ingestion. The common mnemonic “MUDPILES” may be helpful for remembering these.
Option A is correct because diarrhea leads to normal anion gap metabolic acidosis.
Option B is incorrect because methanol leads to elevated anion gap metabolic acidosis.
Option C is incorrect because diabetic ketoacidosis leads to elevated anion gap metabolic acidosis.
Option D is incorrect because uremia leads to elevated anion gap metabolic acidosis.

Question 49

A 25-year-old G2P1 woman at 34 weeks gestational age with preeclampsia that was hospitalized 2 hours ago and is now stable following administration of magnesium sulfate and methyldopa. She had previously been complaining of blurred vision and scotomata. Her prior pregnancy resulted in an uncomplicated vaginal delivery at 39 weeks. Labs are obtained and are remarkable for a platelet count of 89,000/μL, AST 139 IU/L and ALT 110 IU/L. Which of the following represents the most appropriate course of action for definitive treatment for this patient?

A. Emergency cesarean section

B. Induction of labor trial

C. Bed rest until 37 weeks

D. Continued follow up until 34 weeks followed by cesarean section

Answer 49

The definitive treatment of preeclampsia is delivery. This patient meets criteria for preeclampsia with severe features. Prior to <34 weeks gestational age preeclampsia with severe features may be managed with expectant management. This decision must be individualized and the risks and benefits must be considered. However, this patient is at 34 weeks gestation age. Therefore, attempting vaginal delivery, in this case, is most appropriate in this scenario. Prolonging the pregnancy at this point subjects both the mother and the baby to significant risks with limited benefit. Route of delivery for these patients is based on standard obstetrical indications. Unless there are contraindications, a trial of induction is appropriate, making the Option B the correct choice.
Option A would be incorrect as cesarean section is not necessarily indicated for the diagnosis of preeclampsia with severe features. It is indicated if induction fails or if there are other obstetric factors such as unfavorable cervical exam. This patient had a prior uncomplicated vaginal delivery, decreasing the likelihood of problems with cephalopelvic disproportion for a potential upcoming vaginal delivery.
Options C and D are both incorrect as conservative management is not appropriate for this patient with preeclampsia with severe features.
Option E is incorrect as corticosteroids for fetal lung maturity are not indicated here. A single course is indicated between 24+0/7 weeks and 33+6/7 weeks if there is a high risk for preterm delivery within 7 days. In addition, it would not be definitive treatment for the mother’s preeclampsia.

Question 50

Absolute contraindications to neuraxial blockade

Answer 50

The absolute contraindications for neuraxial blockade are as follows: patient refusal, infection at the site of injection, severe hypovolemia, coagulopathy or other bleeding diathesis, increased intracranial pressure, severe aortic stenosis, and severe mitral stenosis

Question 51

A neonate is delivered by C-section for breech presentation. Which one of the following factors in the neonate facilitates the successful transition from fetal to neonatal circulation?

A. Decreased systemic vascular resistance

B. Reversal of flow through the foramen ovale

C. Increased right ventricular contractility

D. Decreased pulmonary vascular resistance

E. Anatomic closure of the ductus arteriosus

Answer 51

Successful transition from fetal to neonatal circulation is dependent on the following series of events:

• As soon as the baby is delivered, the umbilical cord is clamped and the baby is separated which increases the systemic vascular resistance (SVR).
• The baby is placed under the radiant warmer and dried with a towel. Meanwhile, nasopharynx and oropharynx is thoroughly suctioned. These stimuli initiate the crying, resulting in lung expansion and decrease in the pulmonary vascular resistance (PVR).
• The changes in the SVR and the PVR result in physiologic closure of the foramen ovale and the ductus arteriosus. The venous return from the SVC and IVC is ejected from the right heart (right ventricular contraction) and oxygenation occurs at the lungs and the oxygenated blood is returned to the left heart for ejection into the systemic circulation.

Question 52

While doing the morning rounds, the attending asks what the plasma osmolality of a 62-year-old diabetic patient is. Her lab values are sodium 141 mEq/L, glucose 322 mg/dL, blood urea nitrogen 20 mg/dL and potassium 3.7 mEq/L. Which of the below is the approximate estimated plasma osmolality of this patient?

A. 310 mOsm/kg

B. 487 mOsm/kg

C. 157 mOsm/kg

D. Not enough lab values to calculate

Answer 52

This case describes a diabetic patient, who has been hospitalized. Osmolality is the concentration of combined solutes in water measured with the amount of solute per kg of solution (i.e. plasma). Normal osmolality is between 275 and 290 mOsm/kg. Osmolar gap is present when the measured osmolality exceeds the estimated osmolality by >10 mOsm/kg. It is usually due to unmeasured osmotically active substances such as alcohol. The calculation to estimate the plasma osmolality (mOsm/kg) is 2x(serum Na in mEq/L) + Glucose (in mg/dL) / 18 + Blood Urea Nitrogen (in mg/dL) / 2.8; which in this patient approximates to about 310 mOsm/kg, Option A. Potassium and other lab values have no direct use in the estimation of osmolality.

Question 53

A 55-year-old man presents to the emergency department an hour after sustaining injuries during a fire at the restaurant at which he works. He was trapped inside the building for around 30 minutes. The patient has no past history of any serious illness and is on no medication. The patient on arrival is alert and appears to be uncomfortable. GCS is 13. Vitals are pulse 113/min, blood pressure 108/70 mmHg, and respiratory rate 17/min. Pulse oximetry on room air shows an oxygen saturation of 98%. Examination shows multiple second-degree burns over the chest and bilateral upper extremities along with third-degree burns over the face. Black sediments are seen within the nose and the mouth. Respiratory and cardiac exam shows no abnormality. The patient is started on lactated Ringer’s solution. Which of the given is the most appropriate next step?

A. Intubation and mechanical ventilation

B. Dressing and bandaging of wounds

C. Hyperbaric oxygen therapy

D. Immediate bronchoscopy

Answer 53

The correct option is intubation and mechanical ventilation. This patient is presenting with a history of severe burns with likely exposure to soot within the nose and mouth. Thermal inhalational injury requires immediate action. Burn-related injury often leads to the development of upper airway edema and obstruction. Therefore, intubation in such patients should not be delayed. Dressing and bandage of wounds are incorrect even though this is the definitive management for second-degree burns. This person was trapped in a burning building. Therefore, inhalation thermal injury should be of utmost concern. Hyperbaric oxygen therapy is indicated in case of carbon monoxide poisoning. Patients present with confusion, headache, nausea, and most importantly, a “cherry-red” skin tone, this patient lack the specific presentation for a diagnosis. Immediate bronchoscopy is incorrect as that is used to confirm a diagnosis of thermal injury, and also aid in the process of intubation. Since intubation has not been attempted yet and there are no signs suggesting of difficult intubation, it is not needed.

Question 54

A 45-year-old patient who is morbidly obese (BMI > 65) with a history of OSA is scheduled for a knee arthroscopy. Which of the following is a recommendation of the American Society of Anesthesiologists which applies to this patient?

A. General anesthesia is to be avoided if moderate to deep sedation can provide adequate comfort for this patient

B. Major conduction anesthesia (spinal/epidural) is likely to result in more risk than general anesthesia

C. The use of CPAP or an oral appliance during sedation has no benefits

D. Neuraxial opioids are associated with lower frequencies of respiratory depression, somnolence, and sedation compared to systemic opioids

Answer 54

Answer D is correct because randomized controlled trials have shown that systemic opioids result in higher rates of respiratory depression and sedation than neuraxial opioids.
Answer A is incorrect because the ASA recommends that general anesthesia with a secure airway is preferable to deep sedation.
Answer B is incorrect because the ASA recommends that spinal/epidural anesthesia should be considered for peripheral procedures.
Answer C is incorrect because the ASA recommends the use of CPAP or oral appliances during sedation if at all possible.

Question 55

A 20-year-old man presents for bowel resection for ulcerative colitis. He is otherwise healthy. However, family history reveals that his father has been diagnosed with malignant hyperthermia via muscle biopsy and caffeine-contracture test. The patient has himself never been tested for MH susceptibility but has had a prior general anesthetic with sevoflurane without difficulty. He has never had problems with rhabdomyolysis or other post-exercise symptoms suggestive of MH susceptibility. What testing does he need to undergo prior to another general anesthetic?

A. None. Prior lack of triggering of an MH episode by sevoflurane means he does not have MH susceptibility.

B. Muscle biopsy with caffeine-halothane contracture testing (CHCT)

C. Genetic testing for RYR1 genetic mutation

D. None. The patient can safely undergo anesthesia using a non-triggering technique and an anesthesia machine that has been properly prepared and flushed

Answer 55

Having a primary relative (parent, sibling, child) with proven MH susceptibility greatly increases the risk that a patient is also MH susceptible, which in the past was considered to be inherited in an autosomal dominant fashion. Prior uneventful general anesthesia does not reliably rule out MH susceptibility; there are many reports of MH episodes in patients who previously underwent uneventful general anesthesia with volatile agents. MH susceptible patients can safely undergo general anesthesia with a non-triggering technique, although care must be given to prepare the anesthesia machine if a dedicated MH machine is not available. This consists of removing the vaporizers, replacing the CO2 absorbent, and (of course) new breathing circuit and fresh gas hose. The machine should be flushed with fresh gas for between 10 to 30 minutes, depending on the agents that have been used, and the type of machine. Manufacturer’s recommendations should be sought and followed.
Fresh gas flow should be maintained at 10L/min during the case to avoid rebound accumulation of volatile agent within the machine. It is recommended that all primary relatives of a patient with known susceptibility to MH be tested if possible; about half of offspring of someone with MH susceptibility will also be susceptible, although the genetics are more complex than simple autosomal dominant inheritance. Testing can help reassure relatives that they are not susceptible, and also allow proper counseling of patients who show positive susceptibility. CHCT is the “gold standard” for determining if a patient is MH susceptible in North America, and a similar test, the halothane and caffeine muscular contracture test (aka the IVCT) is used in Europe. The IVCT is 99% sensitivity and specific for MH susceptibility, and the CHCT had a reported sensitivity of 97% and 78% respectively.
It is now known that various mutations in the familial RYR1 gene are responsible for 50 to 80% of MH susceptibility, but, other genes and or genetic interactions (e.g. STAC3 proteins) are likely also be involved. Because of the low sensitivity of genetic testing for RYR1 abnormalities, genetic testing is not recommended for screening over functional CHCT or IVCT testing. The problems with CHCT testing in North America is that there are only 5 centers that currently do the test (in Toronto, Bethesda Maryland, Sacramento California, Minneapolis Minnesota and Winston-Salem North Carolina). Testing requires a surgical procedure with muscle biopsy. Both limit the ability and willingness of patients to undergo testing. Because patients who are MH susceptible can safely undergo general anesthesia using non-triggering techniques, this is the course that is usually chosen in clinical practice.

Question 56

Which of the following patients undergoing a laparoscopic cholecystectomy is most likely to require perioperative steroid administration?

A. 18-year-old male with inflammatory bowel disease who takes 20 mg of prednisone daily for last year

B. 74-year-old female with a prior lumbar spine fusion that received a recent lumbar epidural steroid injection

C. 65-year-old female with COPD on an inhaled beclomethasone

D. 55-year-old male with rheumatoid arthritis who takes 5 mg prednisone every other day

Answer 56

Patients who take exogenous steroids of any dose under 3 weeks or <5 mg prednisone (or equivalent) daily are unlikely to have a suppressed hypothalamus-pituitary-adrenal (HPA) axis. These patients most likely will not need additional steroid administration perioperatively. People taking prednisone >20 mg daily for 3 weeks ore more and those with a Cushingoid appearance should receive additional perioperative steroids due to the HPA axis suppression. The specific regimen should be adjusted based on the details of the surgery.
Lack of supplementation can lead to an adrenal crisis with hypotension. For those patients in between the previously mentioned guidelines, individual risk-benefit analysis must be performed. Inhaled or topical or spinal glucocorticoids are unlikely to cause overt adrenal insufficiency and may not need perioperative supplemental steroid administration. Option A is correct as this patient is the only one who meets guidelines for additional glucocorticoids.

Question 57

You’re examining a 50kg 36-year-old female patient with acute hypernatremia secondary to Salmonellosis that started yesterday. The patient’s free water deficit is calculated to be 3.8L. An IV infusion with Dextrose 5% with water is ordered. Which of the following should be the approximate rate of infusion in this patient?

A. 150 mL/hour

B. 80 mL/hour

C. 300 mL/hour

D. 40 mL/hour

Answer 57

This case describes a younger patient with hypovolemic hypernatremia due to ongoing losses through nausea and vomiting. The fluid deficit in this patient is calculated to be 3.8L through the use of the free water deficit formula. As a rule of thumb, acute hypernatremia that developed within 24h should be corrected within 24h and hypernatremia that is chronic or of unknown duration should be corrected over 48hours. Correcting 3.8L of deficit equates to around 150mL/hour which is also correct for an initial rate of 3-6 mL/kg/hour in this patient. As such, Option A is the correct choice.

Question 58

A 60-year-old man is extubated in the ICU after undergoing repair of an ascending aorta dissection. During the procedure, all of the arch vessels were preserved. After extubation, the patient’s voice is observed to be hoarse. What would most likely be seen on awake fiberoptic laryngoscopy on this patient?

A. Left vocal cord in an adducted position and right vocal cord fully abducted

B. Left vocal cord in an abducted position and right vocal cord fully adducted

C. Vocal cords in fully abducted position

D. Vocal cords in fully adducted position

Answer 58

The correct option is left vocal cord in an adducted position and right vocal cord fully abducted. Postoperative hoarseness is a result of injury to the motor nerve which innervates the larynx. The left recurrent laryngeal nerve is especially vulnerable to damage in cardiothoracic procedure and neck surgeries due to its anatomical relations. After the left recurrent laryngeal nerve branches off the vagus nerve, it passes in between the left pulmonary artery and the arch of aorta before supplying the larynx. In contrast to that, the right recurrent laryngeal nerve passes under the root of the right subclavian artery. A procedure which involves aortic arch repair would be more likely to damage the left recurrent laryngeal nerve than the right. Damage to the left recurrent laryngeal nerve will result in the left vocal cord being subjected to the unopposed action of the cricothyroid muscle, and this will result in the left cord coming to an adducted position. During inspiration, the vocal cords tense and are abducted; a patient with left nerve injury will have an adducted left cord and abducted right cord. Left vocal cord in an abducted position and right vocal cord fully adducted is incorrect as that is a result of damage to the right recurrent laryngeal nerve. The vocal cords in fully abducted position is incorrect as that would be seen in case of bilateral damage to CN X. The vocal cords in fully adducted position is incorrect as that would be seen in case of laryngospasm.

Question 59

A 57-year-old male patient is being seen in the emergency department for chronic diarrhea that started a month ago. His past medical history is significant for alcoholism and schizophrenia treated with haloperidol. He states he has been having muscle fasciculations and spasms on his feet. He proceeds to have a generalized tonic-clonic seizure that spontaneously aborts. An ECG is ordered and he goes into cardiovascular arrest during the ECG with the following rhythm: Which of the following electrolyte imbalance is the most likely cause of this patient’s rhythm and symptoms?

Answer 59

This case describes a patient with torsades de pointes witnessed on 12-lead ECG. The medical history of this patient is notable for alcoholism and chronic diarrhea both of which are risk factors for Option C, hypomagnesemia. The patient is also on haloperidol, which is a medication known for increasing the QT interval thus the possibility of torsades de pointes in the presence of hypomagnesemia. This patient’s other symptoms such as fasciculations, seizure, and spasm are also easily explained by Option C, which is the correct answer.
While Option A, can also be seen as induced by hypomagnesemia in this patient, it is not the most likely cause of this patient’s signs and symptoms and the ECG findings.
Options B and D, hyperkalemia and hyponatremia, while may cause some of the patient’s symptoms such as seizures, they would not be the causal factor of this patient’s ECG findings, i.e. torsades de pointes.

TREAT WITH MAGNESIUM