4.3 Protocol 14: Drowning, Protocol 15: Electrocution & Protocol 20: Heat / Cold Exposure

4.3 Protocol 14: Drowning, Protocol 15: Electrocution & Protocol 20: Heat / Cold Exposure

Quick Answer: Environmental emergencies combine severe environmental hazards with time-critical physiological collapse. In Protocol 14 (Drowning), the primary rule is rescuer safety ("reach or throw, don't go"), coupled with aggressive CPR in cold water submersions because hypothermia protects the brain ("not dead until warm and dead"). In Protocol 15 (Electrocution), scene safety is absolute: callers must never touch the victim or use makeshift wooden objects until the power utility confirms current is off; all victims require ALS evaluation due to delayed lethal dysrhythmias. In Protocol 20 (Heat/Cold), heat stroke is distinguished from heat exhaustion by altered mental status, requiring immediate active cooling, while severe hypothermia mandates extreme gentle handling to prevent fatal ventricular fibrillation.

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1. Protocol 14: Drowning and Near-Drowning (Submersion Incidents)

Drowning is defined as the process of experiencing respiratory impairment from submersion or immersion in liquid. It represents a primary hypoxemic / asphyxial event that rapidly leads to cardiac arrest if unreversed.

Pathophysiological Cascade of Drowning

1. Submersion and Breath-Holding: When submerged, the victim instinctively holds their breath until hypercapnia forces inspiratory drive.
2. Aspiration vs. Laryngospasm: Small amounts of water entering the larynx trigger intense laryngospasm, temporarily sealing the airway. However, as hypoxia deepens, the laryngeal muscles relax, permitting fluid aspiration into the tracheobronchial tree.
3. Surfactant Destruction: Inhaled water (fresh or salt) washes out and inactivates pulmonary surfactant, precipitating massive alveolar collapse (atelectasis), severe ventilation-perfusion mismatch, non-cardiogenic pulmonary edema, and acute respiratory distress syndrome (ARDS).
4. Asphyxial Cardiac Arrest: Prolonged cerebral hypoxia leads to bradycardia, pulseless electrical activity (PEA), and asystole.

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|                        DROWNING RESPONSE METRICS                        |
|                                                                         |
|   Warm Water (>68°F / 20°C): Brain death occurs within 4-6 minutes      |
|   Cold Water (<43°F / 6°C):  Mammalian dive reflex preserves brain     |
|   Cardinal Resuscitation Rule: "Not dead until warm and dead!"          |
+-------------------------------------------------------------------------+

The Cold Water Drowning Exception: "Warm and Dead"

In cold water submersion (water temperatures below 43°F / 6°C), the human body exhibits the Mammalian Diving Reflex, triggered by cold water striking the ophthalmic branch of the trigeminal nerve. This reflex induces immediate peripheral vasoconstriction, intense bradycardia, and preferential shunting of oxygenated blood exclusively to the cerebral cortex and myocardium. Simultaneously, rapid systemic cooling drops brain temperature, drastically reducing cerebral metabolic demand for oxygen ($CMRO_2$) by approximately 7% per degree Celsius.

Because hypothermia preserves viable neuronal tissue during prolonged anoxia, pediatric and young adult victims submerged in icy water for 30 to 60 minutes or longer have achieved complete neurologically intact resuscitation. Therefore, under MPDS rules:

• The EMD must never assume biological death based purely on prolonged submersion time in cold water.
• If a patient is retrieved from cold water, the dispatcher must immediately instruct full cardiopulmonary resuscitation (T-CPR), regardless of elapsed time.

Spinal Precautions in Diving Accidents

When a drowning incident involves diving into shallow water (e.g., swimming pools, lakes, or sandbars), cervical spine trauma must be assumed. The EMD guides callers to maintain manual in-line cervical stabilization while supporting the victim afloat, keeping their mouth and nose clear of the surface until rescue personnel arrive with a backboard and cervical collar.

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2. Protocol 15: Electrocution and Lightning Strikes

Electrical injuries represent an acute double threat: lethal atmospheric or high-voltage energy threatening bystanders, paired with complex thermal and dysrhythmic trauma within the patient.

Absolute Scene Safety Doctrine

The Cardinal Dispatch Rule for Electrocution: Callers and bystanders must NEVER approach, touch, or attempt to move an electrocution victim until electrical current is physically isolated and confirmed deactivated by the power utility company or fire department.

Callers routinely ask if they can push a fallen high-voltage wire away using a wooden broom handle, a plastic pipe, or a dry branch. The EMD must strictly forbid this action. At voltages exceeding 600 to 1,000 volts (standard residential distribution lines carry 7,200 to 14,400 volts), moisture in wood, microscopic carbon tracks, or atmospheric arcing can conduct thousands of volts directly through the wooden tool into the bystander, instantly creating a second fatal casualty.

Alternating Current (AC) vs. Direct Current (DC) Mechanics

The "Iceberg Effect" in Electrical Trauma

External cutaneous burn marks (entry and exit points) notoriously deceive bystanders and clinicians. Skin has relatively high electrical resistance, whereas deep neurovascular bundles, bone, and skeletal muscle contain high water and electrolyte concentrations, making them excellent conductors. As electrical current courses through the body, massive internal thermal energy is generated ($Joule's\ Law: Q = I^2Rt$), causing deep muscle coagulation, severe rhabdomyolysis, compartment syndrome, and acute renal failure, while surface skin appears minimally scorched.

Delayed Cardiac Dysrhythmias

Even if an electrocution victim is conscious and walking around on scene, the electrical disruption of cardiac cellular conduction can precipitate delayed lethal dysrhythmias (such as ventricular tachycardia, sustained PVC showers, or complete heart block) hours after the shock. All electrical contact patients warrant mandatory ALS transport and continuous 12-lead ECG telemetry.

Lightning Trauma and Reverse Triage

Lightning strikes deliver massive DC energy (up to 300 million volts and 30,000 amperes) lasting milliseconds. Unique presentations include:

• Lichtenberg Figures: Pathognomonic, transient fern-like or feathering arborization patterns on the skin caused by red blood cell extravasation into dermal layers along electrical flow lines.
• Tympanic Membrane Rupture: Acoustic overpressure waves burst eardrums in over 50% of direct strikes.
• Reverse Triage in Mass-Casualty Lightning Incidents: In standard triage (START), non-breathing, pulseless patients are declared dead (Black tag). In lightning mass casualties, this rule is inverted. Lightning-induced asystole often resolves with spontaneous cardiac return of rhythm, but concurrent paralysis of the brainstem respiratory center produces prolonged apnea. If bystanders initiate immediate rescue breathing and compressions, these pulseless victims frequently achieve full recovery.

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3. Protocol 20: Heat Exposure (Exhaustion vs. Heat Stroke)

Thermoregulatory failure occurs along an escalating continuum when ambient heat and relative humidity impair the body's primary cooling mechanism: evaporative perspiration.

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|                        HEAT ILLNESS CONTINUUM                           |
|                                                                         |
|   Heat Cramps:       Muscle spasms; normal core temp; intact sensorium  |
|   Heat Exhaustion:   Profuse sweating; dehydration; NORMAL mental state |
|   HEAT STROKE:       Temp >104°F; ALTERED MENTAL STATUS; EMERGENCY!     |
+-------------------------------------------------------------------------+

Diagnostic Divergence: Heat Exhaustion vs. Heat Stroke

The EMD must master the single definitive clinical discriminator between heat exhaustion and heat stroke: neurological status.

⚠️ Clinical Dispatch Pitfall: The Sweating Heat Stroke Victim

Traditional folklore teaches that heat stroke victims never sweat. This is dangerously false. In exertional heat stroke (seen in young athletes, military recruits, and outdoor laborers), patients collapse with core temperatures exceeding 106°F while their skin remains drenched in profuse sweat. If a patient in a hot environment displays confusion, irrational behavior, or lethargy, they must be coded as Heat Stroke regardless of whether sweating is present.

Dispatch Life Support: Active Cooling Instructions

For confirmed or suspected heat stroke, the dispatcher must coach immediate active cooling before EMS arrival:

1. Move the patient out of direct sunlight into an air-conditioned room or deep shade.
2. Remove heavy, restrictive clothing.
3. Apply cold, wet towels, sheets, or ice packs to high-flow vascular zones: the axillae (armpits), groin, and neck.
4. Fan the patient vigorously while continually misting or sponging their skin with cool water to maximize evaporative cooling.

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4. Protocol 20: Cold Exposure & Severe Hypothermia

Hypothermia is defined as a drop in core body temperature below 95°F (35°C). It is categorized clinically into mild, moderate, and severe stages.

The Hypothermic Continuum

• Mild Hypothermia (90°F–95°F / 32°C–35°C): Shivering is maximal; patient is alert but tachycardic and tachypneic. Vasoconstriction shuts down peripheral perfusion.
• Moderate to Severe Hypothermia (<90°F / <32°C): Shivering ceases (the body can no longer generate endogenous heat). Muscle rigidity, extreme bradycardia, severe bradypnea, and paradoxical undressing occur as hypothalamic thermoregulation collapses. At core temperatures below 82°F (28°C), the patient appears clinically dead, exhibiting unreactive pupils, absent peripheral pulses, and unmeasurable respirations.

The Cardinal Principle: Gentle Handling to Avoid Refractory VFib

In severe hypothermia, the cold myocardium is in a state of extreme metabolic irritability. The resting membrane potential of cardiac myocytes is unstable. Rough physical handling, vigorous jostling, sudden lifting, or aggressive CPR pounding can instantly trigger refractory Ventricular Fibrillation (V-Fib).

The EMD must deliver strict instructions to bystanders:

"Move the patient as gently as possible. Do not shake, jostle, or massage the patient's limbs or body."

Rewarming Rules for Dispatchers

• Passive External Rewarming: Instruct callers to remove wet garments gently by cutting them off if necessary, insulate the patient with dry blankets, sleeping bags, or coats, and protect them from wind and cold ground surfaces.
• Active Rewarming Contraindications: Never instruct callers to place severe hypothermia victims into hot baths or apply intense external heat lamps directly to the extremities. Heating the extremities causes sudden peripheral vasodilation, shunting cold, acidic, potassium-rich pooled venous blood from the arms and legs directly back into the core heart—a lethal phenomenon known as "rewarming shock" (core temperature afterdrop) that precipitates immediate cardiac arrest.