6.1 Medical Emergencies: CPR, AED, Shock, and Anaphylaxis

Medical Emergencies: CPR, AED, Shock, and Anaphylaxis

Medical assistants working in ambulatory care facilities are frequently the first healthcare professionals to recognize and respond to life-threatening medical emergencies. Prompt identification, immediate emergency response, and strict adherence to standardized protocols are critical to preserving life and preventing permanent organ damage.

Basic Life Support (BLS) and CPR Guidelines

Cardiopulmonary Resuscitation (CPR) restores partial flow of oxygenated blood to the brain and myocardium during cardiac arrest. The American Heart Association (AHA) guidelines emphasize high-quality chest compressions to maintain coronary and cerebral perfusion pressure.

High-Quality CPR Parameters

• Compression Rate: 100 to 120 compressions per minute for all age groups.
• Chest Recoil: Allow complete chest recoil after each compression; do not lean on the chest between compressions.
• Minimizing Interruptions: Limit pauses in chest compressions to less than 10 seconds (chest compression fraction >80%).
• Avoid Excessive Ventilation: Deliver each rescue breath over 1 second, just enough to produce visible chest rise.

Advanced Airway CPR

When an advanced airway (endotracheal tube, supraglottic airway) is in place during CPR, compressions are continuous without pauses for ventilation. Rescue breaths are delivered at 1 breath every 6 seconds (10 breaths per minute).

Automated External Defibrillator (AED) Operation

An Automated External Defibrillator (AED) is a portable electronic device that automatically diagnoses life-threatening cardiac arrhythmias and delivers an electrical shock to re-establish an effective rhythm.

Indications and Cardiac Rhythms

• Shockable Rhythms: Ventricular Fibrillation (V-Fib / VF) and Pulseless Ventricular Tachycardia (pVT).
• Non-Shockable Rhythms: Asystole (flatline) and Pulseless Electrical Activity (PEA). High-quality CPR must continue for non-shockable rhythms.

Step-by-Step AED Execution

1. Power ON: Turn on the AED immediately upon arrival (opens case or presses power button).
2. Apply Pads: Apply adhesive electrode pads to the patient's bare, dry chest.
   • Adult Placement (Anterolateral): Upper right chest below the clavicle; lower left chest below the axilla.
   • Pediatric Pads: Use child pads/attenuator for patients <8 years or <55 lbs. If pads risk touching, use anterior-posterior placement (center chest and center back).
3. Plug in Connector: Connect pad cables to the AED unit if not pre-connected.
4. Clear and Analyze: Announce loudly "Clear!" Ensure no one touches the patient while the AED analyzes the heart rhythm.
5. Deliver Shock if Advised: If a shock is indicated, ensure all personnel are clear and press the Shock button.
6. Resume CPR: Immediately resume high-quality chest compressions starting with compressions, regardless of whether a shock was delivered.

Special Clinical Considerations

• Water/Sweat: Wipe a wet chest dry before pad placement. Move patient out of standing water.
• Implanted Pacemaker/ICD: Place AED pad at least 1 inch (2.5 cm) away from the visible bulge of an implanted pacemaker or defibrillator.
• Transdermal Patches: Remove medication patches (e.g., nitroglycerin, fentanyl) with gloved hands and wipe skin clean before applying pads.
• Hairy Chest: Press pads firmly. If the AED signals "check pads," quickly pull off the pads to remove hair or shave the pad sites.

Classification of Shock, Etiology, and Emergency Interventions

Epinephrine Auto-Injector (EpiPen) Administration

Anaphylaxis is an acute, life-threatening systemic allergic reaction that leads to airway constriction and vascular collapse. Epinephrine is the primary drug of choice, working via alpha-1 agonist activity (vasoconstriction) and beta-1/beta-2 agonist activity (bronchodilation and cardiac stimulation).

Dosage and Administration Protocol

• Dosage: Adult dose is 0.3 mg (EpiPen); Pediatric dose (15–30 kg) is 0.15 mg (EpiPen Jr).
• Site: Mid-outer thigh in the vastus lateralis muscle (can inject through clothing if necessary).
• Angle: Administer firmly at a 90-degree angle into the anterolateral thigh.
• Duration: Hold auto-injector firmly in place for 3 seconds (or up to 10 seconds according to specific manufacturer instructions).
• Post-Injection: Remove device and massage the injection site for 10 seconds to accelerate systemic absorption.
• Secondary Action: Call 911 immediately. A second dose may be administered 5 to 15 minutes after the first dose if severe symptoms persist or recur.

Syncope Management and Safety Warnings

Syncope (fainting) is a transient loss of consciousness caused by temporary inadequate cerebral blood flow. In the clinical setting, vasovagal syncope is frequently triggered by venipuncture, anxiety, pain, or prolonged standing.

Clinical Presentation

Patients entering a presyncopal state exhibit pallor, diaphoresis (cold sweat), dizziness, nausea, tunnel vision, and bradycardia.

Emergency Management Protocol

1. Positioning: Immediately place the patient in a supine position with legs elevated 8 to 12 inches (Trendelenburg position) to enhance venous return to the heart and brain.
2. Airway & Clothing: Loosen restrictive clothing around the neck, chest, and waist.
3. Comfort Measures: Apply a cool, damp cloth to the patient's forehead and back of the neck.
4. Recovery Observation: Keep the patient supine until full consciousness and normal vital signs return. Assist the patient to sit up slowly before standing to prevent orthostatic recurrence.

CONTRAINDICATION WARNING: Ammonia Inhalants (Smelling Salts) The use of ammonia inhalant capsules is contraindicated in modern medical assisting practice. Inhaling concentrated ammonia vapors triggers an involuntary, violent head/neck withdrawal reflex that can aggravate unsuspected cervical spine trauma. Furthermore, ammonia gas can induce severe bronchospasm and respiratory distress in patients with asthma or chronic obstructive pulmonary disease (COPD).