Emergency Drugs and ACLS Flashcards

A patient in the dental chair develops pulseless ventricular tachycardia. After initiating CPR, the first defibrillation attempt at 200J (biphasic) fails to convert the rhythm. Which drug and dose should be administered NEXT according to ACLS guidelines?

Answer: Epinephrine 1 mg IV/IO, then resume CPR for 2 minutes before reassessing

For shockable rhythms (pVT/VF) that fail initial defibrillation, ACLS protocol calls for epinephrine 1 mg IV/IO every 3–5 minutes, given during CPR cycles — NOT immediately after a failed shock. Amiodarone (300 mg) is given after the third shock, not the first failed shock. Vasopressin was removed from the 2015 AHA ACLS algorithm as a replacement option. Lidocaine is an acceptable alternative to amiodarone but only after the third shock.

During monitored sedation, a 62-year-old patient develops a narrow-complex tachycardia at 180 bpm with a blood pressure of 88/50 mmHg and altered consciousness. The MOST appropriate immediate intervention is:

Answer: Synchronized cardioversion starting at 50–100J

This patient has an unstable SVT with serious signs (hypotension, altered consciousness). Unstable tachycardia with a pulse requires immediate synchronized cardioversion regardless of rhythm type — starting at 50–100J for narrow-complex SVT. Adenosine and vagal maneuvers are first-line only for stable SVT. Amiodarone may be used for stable wide-complex tachycardia or as an adjunct, not as primary therapy for unstable narrow-complex tachycardia.

A dental patient receiving IV sedation develops severe bronchospasm refractory to two doses of albuterol. SpO₂ is 82% and the patient is becoming fatigued. Which agent represents the MOST appropriate next pharmacologic intervention?

Answer: Epinephrine 0.3 mg IM (1:1,000) in the lateral thigh

Severe, refractory bronchospasm with hypoxia and patient fatigue is a life-threatening emergency. Epinephrine IM (1:1,000, 0.3 mg) is the drug of choice because it rapidly reverses bronchospasm via β₂ agonism AND addresses any anaphylactic component via α₁ and β₁ activity. Diphenhydramine has no meaningful bronchodilator effect. Corticosteroids take hours to work. Magnesium sulfate is a useful adjunct in the ED for severe asthma but is not the immediate priority in a rapidly deteriorating patient; epinephrine acts in minutes.

A patient receiving nitrous oxide/oxygen sedation suddenly loses consciousness and develops rhythmic tonic-clonic seizure activity. After activating EMS and positioning the patient, which drug sequence is MOST appropriate if IV access is available?

Answer: Midazolam 0.1–0.2 mg/kg IV as first-line benzodiazepine, then lorazepam if needed

Midazolam (0.1–0.2 mg/kg IV) is the preferred first-line agent for active seizures when IV access is available, due to its rapid onset and short duration. Diazepam is also acceptable but midazolam is now preferred in most emergency protocols. Flumazenil is CONTRAINDICATED in seizure management — it can precipitate refractory seizures in benzodiazepine-dependent patients and should never be given during active seizure activity. Thiamine/glucose considerations apply in specific situations (suspected hypoglycemia or alcoholism) but are not the pharmacologic priority for active tonic-clonic seizures.

During deep sedation, a patient's ETCO₂ waveform becomes flat and SpO₂ drops to 74% despite jaw thrust and oral airway placement. Bag-mask ventilation is initiated. Which of the following regarding epinephrine use in this scenario is CORRECT?

Answer: Epinephrine is contraindicated until a pulse is confirmed absent, as it can induce VF in a perfusing rhythm

This scenario describes respiratory arrest, not cardiac arrest — the patient still has a perfusing rhythm. Epinephrine 1 mg IV (cardiac dose) is indicated ONLY in pulseless cardiac arrest. Administering it to a patient with a pulse can cause dangerous hypertension, severe tachycardia, and can induce ventricular fibrillation. The correct management is aggressive airway management and ventilatory support. Epinephrine IM (anaphylaxis dose) would only be appropriate with clinical signs of anaphylaxis, which are not described here.

A post-sedation patient is found unresponsive with a palpable pulse of 40 bpm and a blood pressure of 70/40 mmHg. The monitor shows a regular wide-complex rhythm at 38 bpm with P-waves that are dissociated from QRS complexes. Which intervention is the DEFINITIVE treatment for this rhythm?

Answer: Transcutaneous pacing while preparing for transvenous pacing

The rhythm described is complete (third-degree) heart block with a ventricular escape rhythm — evidenced by AV dissociation, wide QRS, and severe bradycardia. Atropine is ineffective for third-degree heart block at the ventricular level because vagolytic agents cannot overcome infranodal blocks — it may slightly increase atrial rate but cannot conduct through the blocked AV node. Transcutaneous pacing is the immediate bridge therapy and transvenous pacing is the definitive treatment. Dopamine and epinephrine infusions are temporizing measures but not definitive. Recognizing atropine's ineffectiveness in complete heart block is a critical ACLS distinction.