Cardiac and Respiratory Medical Emergencies - NREMT Paramedic Level

1. What is the maximum total adult atropine dose for symptomatic bradycardia per ACLS?

   $3\ \text{mg total}$. Cumulative dosing ensures maximal vagal blockade while minimizing toxicity risks in persistent bradycardia.

2. Which intervention is preferred for unstable tachycardia with a pulse and signs of shock?

   Synchronized cardioversion. It delivers energy timed to the R wave to convert the rhythm safely without inducing ventricular fibrillation.

3. Which ECG interval is prolonged in first-degree AV block?

   PR interval $>0.20\ \text{s}$. Delayed AV node conduction prolongs atrial-to-ventricular impulse time, though every P wave conducts to a QRS.

4. What is the most appropriate initial ventilation strategy for apnea with a pulse?

   BVM ventilation with oxygen. It provides positive pressure to maintain oxygenation and ventilation until advanced airway management.

5. What ECG feature defines complete (third-degree) AV block?

   AV dissociation (P waves and QRS unrelated). Complete conduction failure separates atrial and ventricular rhythms, with escape pacemakers driving QRS independently.

6. Which lung sound is most consistent with lower airway bronchospasm in acute asthma?

   Wheezing. Bronchoconstriction produces high-pitched expiratory sounds from turbulent airflow in narrowed airways.

7. What is the initial adult atropine dose for symptomatic bradycardia per ACLS?

   $1\ \text{mg IV/IO bolus}$. This dose effectively blocks vagal stimulation to raise heart rate without exceeding safe limits initially.

8. What is the initial adult adenosine dose for regular narrow-complex SVT per ACLS?

   $6\ \text{mg rapid IV push, then flush}$. Rapid administration maximizes AV node blockade to terminate reentrant SVT while minimizing side effects.

9. Which ECG rhythm is defined by an irregularly irregular rhythm with no distinct P waves?

   Atrial fibrillation. This rhythm arises from multiple atrial foci firing chaotically, resulting in absent P waves and irregular ventricular response.

10. Which acute coronary syndrome finding most strongly suggests right ventricular infarction?

    ST elevation in V4R. Right-sided leads detect inferior wall extension involving the right ventricle, guiding fluid management.

11. Which clinical finding most strongly indicates immediate needle decompression in trauma?

    Tension pneumothorax with hemodynamic compromise. Trapped air causes mediastinal shift and shock, necessitating urgent pressure relief to restore venous return.

12. Which AV block shows progressive PR prolongation followed by a dropped QRS complex?

    Second-degree AV block Type I (Wenckebach). Progressive AV node fatigue lengthens conduction until failure, creating a pattern of grouped beating.

13. Which medication is first-line for acute bronchospasm relief in asthma or COPD exacerbation?

    Inhaled beta-2 agonist (albuterol). It relaxes bronchial smooth muscle via beta-2 receptor stimulation, rapidly improving airflow.

14. What is the second adult adenosine dose if SVT persists after the first dose per ACLS?

    $12\ \text{mg rapid IV push, then flush}$. Escalated dosing enhances AV node suppression if the initial amount fails to break the tachycardia circuit.

15. Which AV block shows constant PR intervals with intermittent dropped QRS complexes?

    Second-degree AV block Type II (Mobitz II). Fixed conduction block below the AV node causes unpredictable QRS drops without PR changes.

16. Which medication is contraindicated in suspected right ventricular infarction with hypotension?

    Nitroglycerin. It reduces preload, worsening hypotension in preload-dependent right ventricular failure.

17. What is the first-line medication for symptomatic bradycardia with poor perfusion per ACLS?

    Atropine. As a parasympatholytic, it increases heart rate by blocking vagal tone in bradycardic patients with hemodynamic instability.

18. What ECG finding most specifically indicates hypokalemia in a symptomatic patient?

    Prominent U waves. Low potassium disrupts repolarization, leading to visible U waves following the T wave on ECG.

19. What is the first-line antiarrhythmic for stable narrow-complex SVT after vagal maneuvers?

    Adenosine. It transiently blocks AV node conduction, interrupting reentry circuits in supraventricular tachycardias.

20. Which condition classically presents with sudden dyspnea, pleuritic chest pain, and tachycardia?

    Pulmonary embolism. Thrombus occlusion of pulmonary arteries causes ventilation-perfusion mismatch and right heart strain.

21. What is the primary prehospital treatment for suspected opioid-induced respiratory depression?

    Ventilatory support and naloxone. Opioids depress respiratory drive, requiring reversal and mechanical support to restore ventilation.

22. What ECG finding most specifically indicates hyperkalemia in a symptomatic patient?

    Tall, peaked T waves. Elevated potassium levels impair cardiac repolarization, causing characteristic T-wave changes as an early ECG indicator.

23. What oxygen saturation target range is commonly used for COPD patients at risk of hypercapnia?

    $88\%\text{ to }92\%$. Lower targets preserve hypoxic respiratory drive in chronic hypercapnia, avoiding CO2 retention.

24. Which rhythm requires defibrillation rather than synchronized cardioversion when pulseless?

    Ventricular fibrillation. As a chaotic rhythm without organized QRS complexes, it necessitates unsynchronized high-energy shocks to restore sinus rhythm.

25. What is the target adult oxygen saturation range for most acutely ill patients?

    $94\%\text{ to }98\%$. This range balances oxygenation needs while preventing hyperoxia-induced vasoconstriction and oxidative stress.

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