ABFAS Emergency Response Procedures 3 — Questions and Answers
Question 1: A patient in the PACU after ankle surgery develops sudden onset respiratory distress, tachycardia, and hypoxia with oxygen saturation of 84%. Breath sounds are absent on the right. The MOST likely diagnosis is:
- Pulmonary embolism
- Pneumothorax from interscalene nerve block (Correct answer)
- Acute bronchospasm from latex allergy
- Aspiration pneumonia
Correct answer: Pneumothorax from interscalene nerve block
Unilateral absent breath sounds following an interscalene or supraclavicular nerve block strongly suggest ipsilateral pneumothorax, a known complication.
Question 2: A patient with a known penicillin allergy receives cefazolin for surgical prophylaxis and develops urticaria. The cross-reactivity rate between penicillins and cephalosporins is approximately:
- Less than 2% (Correct answer)
- 10-15%
- 25-30%
- 50%
Correct answer: Less than 2%
The true cross-reactivity rate between penicillins and cephalosporins is less than 2%, much lower than historically reported 10% figures.
Question 3: Which finding on arterial blood gas (ABG) is most consistent with acute respiratory failure requiring immediate intubation?
- pH 7.38, PaO2 88 mmHg, PaCO2 42 mmHg
- pH 7.32, PaO2 72 mmHg, PaCO2 48 mmHg
- pH 7.20, PaO2 52 mmHg, PaCO2 58 mmHg on maximal O2 (Correct answer)
- pH 7.44, PaO2 95 mmHg, PaCO2 38 mmHg
Correct answer: pH 7.20, PaO2 52 mmHg, PaCO2 58 mmHg on maximal O2
Severe acidosis (pH 7.20), significant hypoxemia (PaO2 52), and hypercapnia (PaCO2 58) despite maximal supplemental oxygen indicate impending respiratory failure requiring intubation.
Question 4: In a patient with suspected deep vein thrombosis (DVT) following foot and ankle surgery, which initial diagnostic test is most appropriate?
- D-dimer blood test alone
- Lower extremity venous duplex ultrasound (Correct answer)
- CT pulmonary angiography
- Contrast venography
Correct answer: Lower extremity venous duplex ultrasound
Compression duplex ultrasound of the lower extremity is the first-line imaging modality for diagnosing DVT due to its safety, availability, and accuracy.
Question 5: A postoperative patient develops fever of 39.5°C, hypotension, tachycardia, and altered mental status 48 hours after an open reduction internal fixation. Blood cultures are drawn. What is the MOST appropriate immediate intervention?
- Wait for blood culture results before starting antibiotics
- Administer antipyretics and observe for 6 hours
- Begin broad-spectrum IV antibiotics within 1 hour (Correct answer)
- Perform immediate wound exploration in clinic
Correct answer: Begin broad-spectrum IV antibiotics within 1 hour
Sepsis requires broad-spectrum IV antibiotics within 1 hour of recognition per Surviving Sepsis Campaign guidelines to reduce mortality.
Question 6: A patient develops intraoperative hyperthermia of 41°C, masseter muscle rigidity, and mixed metabolic/respiratory acidosis after succinylcholine administration. The MOST likely diagnosis is:
- Neuroleptic malignant syndrome
- Malignant hyperthermia (Correct answer)
- Thyroid storm
- Serotonin syndrome
Correct answer: Malignant hyperthermia
Malignant hyperthermia is triggered by volatile anesthetics and succinylcholine, presenting with hyperthermia, muscle rigidity, and metabolic acidosis from uncontrolled muscle metabolism.
Question 7: What is the specific pharmacologic antidote for malignant hyperthermia?
- Dantrolene sodium 2.5 mg/kg IV bolus (Correct answer)
- Bromocriptine 2.5 mg orally
- Cyproheptadine 12 mg orally
- Physostigmine 2 mg IV
Correct answer: Dantrolene sodium 2.5 mg/kg IV bolus
Dantrolene sodium inhibits calcium release from the sarcoplasmic reticulum, directly treating the underlying pathophysiology of malignant hyperthermia.
ABFAS Emergency Response Procedures 3
A patient in the PACU after ankle surgery develops sudden onset respiratory distress, tachycardia, and hypoxia with oxygen saturation of 84%.
Breath sounds are absent on the right.
The MOST likely diagnosis is: