3.1 Protocol 11: Choking (Foreign Body Airway Obstruction)

Protocol 11: Choking (Foreign Body Airway Obstruction)

Foreign body airway obstruction (FBAO) is one of the most time-critical emergencies encountered in emergency medical dispatch. An acute mechanical occlusion of the upper airway deprives the cerebral cortex of oxygen, leading to loss of consciousness within seconds and irreversible brain death or cardiac arrest within four to six minutes. Within the Medical Priority Dispatch System (MPDS), Protocol 11: Choking provides an algorithmic framework to rapidly differentiate partial from complete airway obstructions, launch appropriate high-priority responses, and guide callers through scripted physical relief maneuvers before field providers arrive.

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1. Pathophysiology: Complete vs. Partial Airway Obstruction

The primary clinical objective during Case Entry and initial interrogation is identifying whether the patient has adequate air exchange (partial obstruction) or absent air exchange (complete obstruction). The larynx and trachea possess sensitive protective reflexes, but when a solid bolus of food, toy, or foreign object becomes impacted at the vocal cords or subglottic space, mechanical airflow ceases.

Clinical Presentation Matrix

The Physiological Danger of Complete Obstruction

In complete obstruction, turbulent airflow cannot pass the obstructing object. Atmospheric pressure drops distal to the occlusion with each strenuous inspiratory effort, creating negative thoracic pressure that can draw the foreign body deeper into the subglottic shelf or carina. Without intervention, hypoxemia induces bradycardia, loss of consciousness, agonal gasps, and ultimately pulseless electrical activity (PEA) or asystolic cardiac arrest.

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2. Dispatch Prioritization and Determinant Architecture

Protocol 11 requires strict adherence to "Send & Go" and fast-track mechanics when complete obstruction is recognized. An emergency medical dispatcher cannot keep a caller answering secondary questions when an airway is totally occluded.

                          [Chief Complaint: Choking / Ingestion]
                                            |
                     -------------------------------------------------
                     |                                               |
           [Patient Conscious]                              [Patient Unconscious]
                     |                                               |
       -----------------------------                         [11-E-1 / 11-D-2]
       |                           |                                 |
[Can Speak or Forceful Cough?]  [Cannot Speak/Breathe/Cough]  [Immediate ECHO Dispatch]
       |                           |                                 |
       |                           |                      [DLS: Unconscious Choking]
  [PARTIAL OBSTRUCTION]     [COMPLETE OBSTRUCTION]            (Compressions First)
       |                           |
[11-A-1 or 11-D-1 Dispatch]  [11-E-1 ECHO Dispatch]
       |                           |
[Encourage Forceful Cough]  [Immediate Transfer to DLS]
[Strictly NO Thrusts/Slaps] [Conscious Choking DLS Link]

MPDS Determinant Codes for Protocol 11

Protocol 11 has only four determinant codes, and the boundary that matters is complete versus partial obstruction — not conscious versus unconscious:

• 11-E-1 (ECHO Level): Complete obstruction / Ineffective breathing. This is the code for a complete airway obstruction whether the patient is still conscious or has collapsed. It triggers the maximum prehospital response (closest ALS and first responders dispatched HOT with lights and siren); the calltaker bypasses all remaining Key Questions and transitions directly to Dispatch Life Support (DLS).
• 11-D-1 (DELTA Level): Abnormal breathing (partial obstruction). The patient is still moving some air but breathing abnormally — stridor, a weak or ineffective cough, or noisy laboured respirations. Immediate high-priority response.
• 11-D-2 (DELTA Level): Not alert. The choking patient has a decreased level of consciousness.
• 11-A-1 (ALPHA Level): Not choking now — the patient can talk or cry, is alert, and is breathing normally. Standard BLS response.

There is no BRAVO or CHARLIE level on Protocol 11. A frequently tested consequence: when a caller reports that a choking patient can no longer make any sound, the EMD must code 11-E-1 (ECHO), not a DELTA code, and move immediately to the choking DLS Link.

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3. Caller Management and Protocol Rules for Partial Obstruction

When the caller reports that a choking individual is coughing loudly and forcefully, the caller's natural instinct is often to intervene aggressively—hitting the patient on the back, offering water, or attempting to reach down their throat. In emergency medical dispatch, the EMD must deliver firm, non-discretionary instructions to prevent well-intentioned bystanders from precipitating a fatal airway compromise.

Critical Operating Rules for Partial Obstruction

1. Encourage Forceful Coughing: The human cough is capable of generating expiratory velocities exceeding 100 miles per hour and subglottic pressures over 200 mmHg. This endogenous airflow is vastly more effective at expelling a foreign body than external manual thrusts.
2. Strictly Forbid Back Slaps on a Coughing Adult or Child: Delivering a sudden blunt blow to the back of a coughing patient can dislodge a movable, sub-totally occluding object and wedge it firmly into the narrowest portion of the laryngeal inlet, converting a manageable partial obstruction into a catastrophic complete obstruction.
3. Strictly Forbid Abdominal Thrusts (Heimlich): External thrusts applied while the patient maintains active air exchange interfere with the patient's respiratory rhythm, induce panic, and risk internal soft-tissue trauma.
4. Never Give Liquids or Food: Callers frequently ask if the patient should drink water or swallow bread to "wash it down." Liquids cannot bypass a physical occlusion; instead, fluids pool in the pharynx, provoke immediate laryngeal spasm, and enter the tracheobronchial tree through pulmonary aspiration.
5. Absolute Prohibition of Blind Finger Sweeps: Blindly inserting fingers into a patient's mouth is strictly forbidden. It pushes the foreign body down the oropharynx, impacts the epiglottis over the glottic aperture, and risks severe bite injuries to the rescuer.

⚠️ Clinical Dispatch Trap: The Silent Patient

If a caller states, "He was coughing violently a second ago, but now he's quiet and his face is turning blue," the partial obstruction has converted into a complete obstruction. The dispatcher must immediately upgrade the response to ECHO (11-E-1, Complete obstruction / Ineffective breathing), suspend non-critical questioning, and launch conscious choking instructions.

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4. Age-Specific Dispatch Life Support (DLS) Interventions

Dispatch Life Support protocols provide precise, scripted physical maneuvers depending on the age, physical condition, and consciousness level of the choking victim.

Infant (<1 Year) Anatomical Differentiation

In infants under one year of age, abdominal thrusts are absolutely contraindicated. The infant liver and spleen are relatively large, fragile, and minimally protected by the undeveloped lower rib cage. Applying subdiaphragmatic thrusts to an infant carries an exceptionally high risk of lacerating the liver, rupturing the spleen, and causing fatal intra-abdominal hemorrhage.

The IAED scripted protocol for an infant conscious obstruction requires alternating:

• Five distinct back slaps: Rescuer holds the infant face down along the forearm, supporting the head and jaw with the hand, with the head kept lower than the trunk. Five sharp slaps are delivered between the shoulder blades with the heel of the opposite hand.
• Five distinct chest thrusts: The infant is turned supine onto the other forearm, supporting the occiput, head lower than the chest. Five downward chest compressions are delivered using two fingers centered on the lower half of the breastbone.

Transition to the Unconscious Choking Protocol

If a patient loses consciousness while choking:

1. The dispatcher instructs the caller to support the patient and ease them gently onto a firm, flat surface (the floor).
2. Dispatch confirms the response is upgraded to ECHO or maximum ALS priority.
3. The dispatcher guides the caller directly into CPR instructions, beginning with chest compressions (30 compressions in adults and children).
4. Compressions generate artificial intrathoracic pressure spikes that frequently dislodge the impacted foreign body upward into the oral cavity.
5. Before ventilations are attempted, the caller is instructed to look into the mouth. If and only if a loose object is clearly seen, the caller is instructed to remove it with a targeted finger sweep. If no object is visible, the caller must never sweep blindly; they immediately attempt two rescue breaths and resume compressions.

5. Realistic Dispatch Scenarios and Scripting

Scenario: Conscious Adult Complete Airway Obstruction at a Restaurant

Caller: "Help! My friend was eating steak and suddenly grabbed his throat! He's turning blue and can't make a sound!"

EMD: "I am sending the paramedics to you right now. Stay on the line. Can he cough or speak at all?"

Caller: "No! Nothing! He's just waving his arms and choking!"

EMD: [Fast-track 11-E-1 ECHO response to CAD. Direct transfer to the conscious-choking DLS Link] "Listen carefully. Stand behind him and wrap your arms around his waist. Make a fist with one hand and place the thumb side of your fist against his stomach, just above his belly button. Grasp your fist with your other hand. Pull hard inward and upward into his belly, like you are trying to lift him up. Do this repeatedly until the food pops out or he passes out. Tell me what happens!"

Caller: "One, two, three—it popped out! A chunk of meat flew out! He's coughing and drawing in air now!"

EMD: "Good, keep him sitting up. Let him cough on his own. Do not give him anything to drink. The paramedics are already on the way to evaluate him."

Critical Exam Pitfalls

• The Blind Sweep Reflex: Many laypersons and untrained test candidates believe a finger sweep should be done immediately upon encountering a choking patient. IAED protocols explicitly dictate that blind finger sweeps are forbidden. Only a visible, loose object may be hooked out.
• The "Slap the Back" Myth: In public folklore, hitting a choking adult on the back is ubiquitous. On the IAED exam, remember: never slap the back of a coughing adult. Back blows are reserved exclusively for infants under one year (in combination with chest thrusts) or specific unconscious airway clearance maneuvers under local medical direction.
• Water Administration Hazard: Giving water to a choking patient is a critical protocol failure. It converts an airway problem into an aspiration emergency.