Anesthesia and Perioperative medicine US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Anesthesia and Perioperative medicine. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Anesthesia and Perioperative medicine US Medical PG Question 1: A 4-year-old boy is brought to the emergency department by his mother after cutting his buttock on a piece of broken glass. There is a 5-cm curvilinear laceration over the patient's right buttock. His vital signs are unremarkable. The decision to repair the laceration is made. Which of the following will offer the longest anesthesia for the laceration repair?
- A. Lidocaine
- B. Lidocaine mixed with bupivacaine
- C. Bupivacaine with epinephrine (Correct Answer)
- D. Lidocaine with epinephrine
- E. Bupivacaine
Anesthesia and Perioperative medicine Explanation: ***Bupivacaine with epinephrine***
- **Bupivacaine** is a long-acting local anesthetic, and adding **epinephrine** to it further prolongs its duration of action by causing vasoconstriction, which slows systemic absorption.
- This combination would provide the **longest duration of anesthesia** suitable for a laceration repair that requires extended pain control.
*Lidocaine*
- **Lidocaine** is an intermediate-acting local anesthetic with a relatively shorter duration of action compared to bupivacaine.
- While effective for initial anesthesia, its effect would likely wear off sooner than desired for a comprehensive repair.
*Lidocaine mixed with bupivacaine*
- Mixing lidocaine with bupivacaine can provide a **faster onset of action** (due to lidocaine) and a longer duration (due to bupivacaine) as compared to lidocaine alone.
- However, the overall duration would typically still be *shorter* than bupivacaine with epinephrine due to the lack of vasoconstriction from epinephrine, leading to faster systemic absorption.
*Lidocaine with epinephrine*
- Adding **epinephrine** to **lidocaine** prolongs its duration of action by inducing vasoconstriction.
- While this is a practical choice for many procedures, bupivacaine inherently has a longer duration than lidocaine, making *bupivacaine with epinephrine* the longest-acting option among those given.
*Bupivacaine*
- **Bupivacaine** alone provides longer anesthesia than lidocaine alone.
- However, without **epinephrine**, its duration is not as long as it could be, as epinephrine would delay its absorption and prolong its local effect.
Anesthesia and Perioperative medicine US Medical PG Question 2: A 37-year-old woman undergoes diagnostic laparoscopy under general anesthesia for evaluation of chronic pelvic pain. Postoperatively, the patient requires prolonged intubation. Neostigmine is administered. Results of acceleromyography during train-of-four ulnar nerve stimulation are shown. Which of the following drugs is most likely to have been used intraoperatively in this patient?
- A. Tizanidine
- B. Clonazepam
- C. Ropivacaine
- D. Succinylcholine (Correct Answer)
- E. Rocuronium
Anesthesia and Perioperative medicine Explanation: ***Succinylcholine***
- The scenario describes a patient requiring **prolonged intubation** and the administration of **neostigmine** for neuromuscular blockade reversal, along with **acceleromyography** results.
- This constellation points to the use of a **depolarizing neuromuscular blocker** like succinylcholine, especially if the patient has atypical plasma **pseudocholinesterase activity**, leading to prolonged paralysis.
*Tizanidine*
- Tizanidine is an **alpha-2 adrenergic agonist** used as a centrally acting muscle relaxant.
- It does not cause neuromuscular blockade that requires reversal with **neostigmine** or monitoring with **acceleromyography** during general anesthesia.
*Clonazepam*
- Clonazepam is a **benzodiazepine** used as an anxiolytic and anticonvulsant.
- It acts on **GABA-A receptors** in the central nervous system and does not directly affect the neuromuscular junction.
*Ropivacaine*
- Ropivacaine is a **local anesthetic** that blocks voltage-gated sodium channels in nerve membranes.
- It is used for regional anesthesia or epidurals and does not cause generalized neuromuscular paralysis requiring such reversal.
*Rocuronium*
- Rocuronium is a **nondepolarizing neuromuscular blocker**, which would also cause neuromuscular blockade.
- However, the description of prolonged intubation followed by neostigmine (an anticholinesterase) could indicate **phase II block** from rocuronium, but the phrasing more strongly suggests **succinylcholine** given the potential for prolonged action due to pseudocholinesterase deficiency.
Anesthesia and Perioperative medicine US Medical PG Question 3: A 52-year-old obese man is brought to the emergency department 30 minutes after he was involved in a high-speed motor vehicle collision. He was the unrestrained driver. On arrival, he is lethargic. His pulse is 112/min, respirations are 10/min and irregular, and blood pressure is 94/60 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 91%. The pupils are equal and react sluggishly to light. He withdraws his extremities to pain. There are multiple bruises over his face, chest, and abdomen. Breath sounds are decreased over the left lung base. Two large bore peripheral venous catheters are inserted and 0.9% saline infusion is begun. Rapid sequence intubation is initiated and endotracheal intubation is attempted without success. Bag and mask ventilation is continued. Pulse oximetry shows an oxygen saturation of 84%. The patient has no advance directive and family members have not arrived. Which of the following is the most appropriate next step in the management of this patient?
- A. Nasotracheal intubation
- B. Video laryngoscopy
- C. Cricothyrotomy (Correct Answer)
- D. Comfort measures only
- E. Tracheostomy
Anesthesia and Perioperative medicine Explanation: ***Cricothyrotomy***
- In a trauma patient with **failed endotracheal intubation** and declining oxygen saturation (from 91% to 84% despite bag-mask ventilation), an emergent cricothyrotomy is indicated for **immediate airway control**.
- This procedure provides a definitive airway in a **can't intubate/can't ventilate** scenario, preventing further hypoxia and potential brain damage.
*Nasotracheal intubation*
- **Nasotracheal intubation** is generally contraindicated in patients with suspected **facial or skull base fractures** due to the risk of intracranial intubation.
- Given the high-speed collision and facial bruises, such fractures are possible, making this a less safe option compared to cricothyrotomy.
*Video laryngoscopy*
- While **video laryngoscopy** can be helpful for difficult airways, it was already implied that intubation was attempted and failed, suggesting the issue might be with visualization or access, not just technique.
- Critically, the patient's oxygen saturation is dropping rapidly, requiring a quicker, more definitive solution than another attempt at orotracheal intubation.
*Comfort measures only*
- The patient has **no advance directive**, and family members have not arrived to make decisions regarding end-of-life care.
- Despite the severity of his injuries, the patient is still alive and does not have clear indications for **comfort measures only** at this stage; resuscitative efforts are warranted.
*Tracheostomy*
- **Tracheostomy** is a surgical procedure for establishing a long-term airway and is not suitable for **emergent airway management** in a rapidly decompensating trauma patient.
- It typically requires specialized surgical expertise and takes longer to perform than a cricothyrotomy, which is a faster, life-saving measure in this acute situation.
Anesthesia and Perioperative medicine US Medical PG Question 4: A 36-year-old male with fluctuating levels of consciousness is brought to the emergency department by ambulance due to a fire in his home. He currently opens his eyes to voice, localizes painful stimuli, responds when asked questions, but is disoriented and cannot obey commands. The patient’s temperature is 99°F (37.2°C), blood pressure is 86/52 mmHg, pulse is 88/min, and respirations are 14/min with an oxygen saturation of 97% O2 on room air. Physical exam shows evidence of soot around the patient’s nose and mouth, but no burns, airway obstruction, nor accessory muscle use. A blood lactate is 14 mmol/L. The patient is started on intravenous fluids.
What is the next best step in management?
- A. Methylene blue
- B. Hyperbaric oxygen
- C. Sodium thiosulfate and sodium nitrite
- D. Intravenous epinephrine
- E. 100% oxygen, hydroxycobalamin, and sodium thiosulfate (Correct Answer)
Anesthesia and Perioperative medicine Explanation: ***100% oxygen, hydroxycobalamin, and sodium thiosulfate***
- This patient presents with signs of both **carbon monoxide poisoning** (fire exposure, disoriented, altered mental status) and **cyanide poisoning** (fire exposure, very high lactate, normal oxygen saturation despite altered mental status). This combination therapy directly addresses both.
- **100% oxygen** competes with carbon monoxide for hemoglobin binding and helps clear it, while **hydroxycobalamin** and **sodium thiosulfate** are antidotes for cyanide poisoning, converting cyanide into less toxic compounds.
*Methylene blue*
- **Methylene blue** is used to treat **methemoglobinemia**, a condition where iron in hemoglobin is oxidized, leading to impaired oxygen transport.
- The patient's symptoms (fire exposure, altered mental status, and a high lactate with normal SpO2) are not characteristic of methemoglobinemia, but rather strong indicators of carbon monoxide and cyanide poisoning.
*Hyperbaric oxygen*
- **Hyperbaric oxygen** is a treatment for severe carbon monoxide poisoning, but it is not the initial or sole treatment for a patient with suspected co-existing cyanide poisoning.
- While recommended for **severe CO poisoning**, it doesn't directly address cyanide toxicity, which is suggested by the metabolic acidosis with a high lactate level despite normal oxygen saturation.
*Sodium thiosulfate and sodium nitrite*
- This combination (the **Lilly kit**) is traditionally used to treat **cyanide poisoning**, with sodium nitrite inducing methemoglobinemia to sequester cyanide, and sodium thiosulfate aiding its excretion.
- The patient also requires treatment for **carbon monoxide poisoning**, and hydroxycobalamin is generally preferred over sodium nitrite as it does not induce methemoglobinemia, which can worsen hypoxia in CO poisoning.
*Intravenous epinephrine*
- **Epinephrine** is a powerful vasoconstrictor and bronchodilator primarily used to treat **anaphylaxis** or **cardiac arrest**.
- There is no indication of anaphylaxis or cardiac arrest in this patient, and epinephrine would not be an appropriate treatment for carbon monoxide or cyanide poisoning.
Anesthesia and Perioperative medicine US Medical PG Question 5: A 30-year-old man with history of intravenous drug use and methamphetamine-associated chronic thromboembolic pulmonary hypertension (CTEPH) is brought to the emergency department by his girlfriend for worsening abdominal pain and fevers. The patient said the pain was initially around his umbilicus, but he is now experiencing intense tenderness near his groin. He was initially prescribed rivaroxaban, but due to insurance issues, he was switched to warfarin for management of CTEPH two weeks ago. His temperature is 102°F (38.9°C), blood pressure is 95/60 mmHg, pulse is 95/min, respirations are 22/min. He states that his blood pressure usually runs low. His physical exam is notable for an unremarkable cardiac exam, bibasilar crackles, and RLQ tenderness with rebound tenderness when the LLQ is palpated. Laboratory results are shown below:
Hemoglobin: 11 g/dL
Hematocrit: 35 %
Leukocyte count: 16,000/mm^3 with normal differential
Platelet count: 190,000/mm^3
Serum:
Na+: 137 mEq/L
Cl-: 100 mEq/L
K+: 3.7 mEq/L
HCO3-: 23 mEq/L
BUN: 40 mg/dL
Glucose: 110 mg/dL
Creatinine: 0.8 mg/dL
Ca2+: 9.1 mg/dL
AST: 34 U/L
ALT: 45 U/L
International normalized ratio (INR): 6.2
Prothrombin time (PT): 40 seconds
Partial thromboplastin time: 70 seconds
Blood type: O
Rhesus: Positive
Antibody screen: Negative
A clinical diagnosis is made and supported by the surgical consult team in lieu of imaging. The next operating room for an add-on procedure will not be available for another 5 hours. Appropriate medical therapy is initiated. What is the best next step for surgical optimization?
- A. Fresh frozen plasma
- B. Prothrombin complex concentrate (Correct Answer)
- C. Protamine
- D. Do nothing
- E. Phytonadione
Anesthesia and Perioperative medicine Explanation: ***Prothrombin complex concentrate***
- The patient has **warfarin over-anticoagulation (INR 6.2)** and requires **emergency surgery** for suspected appendicitis with peritonitis, necessitating rapid reversal of anticoagulation.
- **Prothrombin complex concentrate (4-factor PCC)** contains concentrated factors II, VII, IX, and X (and proteins C & S), providing **rapid and complete reversal** of warfarin's anticoagulant effects within minutes, which is crucial in emergency surgical situations.
- PCC is **preferred over FFP** per current guidelines (ACCP, AHA) for urgent warfarin reversal due to faster administration, smaller volume, and more predictable INR correction.
- **Vitamin K should be administered concurrently** to provide sustained reversal (takes 12-24 hours), but PCC is essential for immediate correction before surgery.
*Fresh frozen plasma*
- While FFP contains all coagulation factors and can reverse warfarin, it requires **larger volumes (4-6 units)**, takes longer to thaw and administer, and is **less effective** in rapidly correcting INR to normal range compared to PCC.
- Administering large volumes of FFP can lead to **volume overload** (especially concerning in CTEPH patients) and **transfusion-related complications**.
- PCC is superior for urgent reversal in patients requiring emergency surgery.
*Protamine*
- **Protamine** is used to reverse the anticoagulant effects of **unfractionated heparin** (and partially reverses low molecular weight heparin), not warfarin.
- It would have **no effect** on the patient's elevated INR due to warfarin use.
- Note: The elevated PTT (70s) in this case may suggest concurrent heparin bridging therapy or other factor deficiency, but the primary issue requiring reversal is the critical warfarin over-anticoagulation.
*Do nothing*
- This patient has **surgical peritonitis** (appendicitis with peritoneal signs) and requires emergency surgery with an INR of 6.2, creating **high risk of surgical bleeding**.
- Proceeding to surgery without reversing anticoagulation would result in **life-threatening hemorrhage**.
- Delaying treatment would likely result in further **clinical deterioration** with possible perforation and sepsis.
*Phytonadione*
- **Phytonadione (Vitamin K)** reverses warfarin's effects by restoring hepatic synthesis of vitamin K-dependent clotting factors, but its onset of action is **slow (12-24 hours for full effect)**, making it unsuitable as the sole agent for immediate reversal in patients requiring emergent surgery.
- While **Vitamin K should be administered** alongside PCC to provide sustained reversal, it is **not sufficient alone** for rapid correction in surgical emergencies.
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