DHA Emergency Medical Services 5 — Questions and Answers
Question 1: A patient presents with altered mental status, bradycardia, miosis, excessive salivation, and urinary incontinence after exposure to an unknown substance. Which antidote is MOST appropriate?
- Naloxone 0.4–2 mg IV
- Atropine 2–4 mg IV and pralidoxime (Correct answer)
- Flumazenil 0.2 mg IV
- Sodium bicarbonate 1–2 mEq/kg IV
Correct answer: Atropine 2–4 mg IV and pralidoxime
The SLUDGE/DUMBELS presentation indicates organophosphate or nerve agent poisoning; atropine reverses muscarinic effects and pralidoxime reactivates acetylcholinesterase.
Question 2: During transport of a STEMI patient, the cardiac monitor shows pulseless ventricular tachycardia. After delivering one shock at 200 J biphasic, what is the IMMEDIATE next step?
- Check pulse and assess rhythm
- Resume CPR immediately for 2 minutes (Correct answer)
- Administer amiodarone 300 mg IV push
- Increase energy to 360 J and shock again
Correct answer: Resume CPR immediately for 2 minutes
Current AHA guidelines mandate immediate resumption of CPR for 2 minutes following any defibrillation attempt before pulse/rhythm reassessment.
Question 3: A pregnant patient at 32 weeks gestation presents with severe headache, BP 168/112 mmHg, and 3+ proteinuria. Which medication is the first-line agent to prevent seizures?
- Diazepam 10 mg IV
- Magnesium sulfate 4–6 g IV loading dose (Correct answer)
- Phenytoin 18 mg/kg IV
- Labetalol 20 mg IV
Correct answer: Magnesium sulfate 4–6 g IV loading dose
Magnesium sulfate is the drug of choice for seizure prophylaxis in severe preeclampsia and treatment of eclamptic seizures.
Question 4: What is the maximum recommended single dose of lidocaine for intraosseous administration in an adult?
- 40 mg (0.5 mg/kg)
- 100 mg (1.5 mg/kg) (Correct answer)
- 200 mg (3 mg/kg)
- 300 mg (4.5 mg/kg)
Correct answer: 100 mg (1.5 mg/kg)
Lidocaine 40–100 mg IO is used to reduce pain during IO infusion, with 100 mg (1.5 mg/kg) being the typical maximum single dose.
Question 5: A patient involved in a high-speed MVA has jugular venous distension, hypotension, and muffled heart sounds. The trachea is midline. What is the MOST likely diagnosis?
- Tension pneumothorax
- Cardiac tamponade (Correct answer)
- Massive hemothorax
- Aortic transection
Correct answer: Cardiac tamponade
Beck's triad — JVD, hypotension, and muffled heart sounds with midline trachea — is classic for cardiac tamponade.
Question 6: Which ventilator setting adjustment is most appropriate for a patient with suspected raised intracranial pressure (ICP) in the pre-hospital setting?
- Target SpO2 ≥94% and ETCO2 35–40 mmHg (normoventilation) (Correct answer)
- Hyperventilate to ETCO2 25–30 mmHg routinely
- Increase PEEP to 10–15 cmH2O
- Reduce tidal volume to 4 mL/kg to lower airway pressures
Correct answer: Target SpO2 ≥94% and ETCO2 35–40 mmHg (normoventilation)
Normoventilation (ETCO2 35–40 mmHg) is recommended; prophylactic hyperventilation causes cerebral vasoconstriction and worsens outcomes.
Question 7: A 55-year-old male with chest pain has a 12-lead ECG showing new left bundle branch block (LBBB). According to the Sgarbossa criteria, which finding carries the HIGHEST specificity for MI?
- ST elevation ≥1 mm concordant with the QRS (Correct answer)
- ST elevation ≥5 mm discordant with the QRS
- ST depression ≥1 mm in leads V1, V2, or V3
- ST elevation ≥2 mm concordant in any lead
Correct answer: ST elevation ≥1 mm concordant with the QRS
Concordant ST elevation ≥1 mm (moving in the same direction as the QRS) has the highest specificity (~94%) for MI in LBBB per Sgarbossa criteria.
DHA Emergency Medical Services 5
A patient presents with altered mental status, bradycardia, miosis, excessive salivation, and urinary incontinence after exposure to an unknown substance.
Which antidote is MOST appropriate?