Submersion Incidents: Drowning and Diving Emergencies Study Guide

Case Study Introduction and Initial Assessment

• Scenario Overview: EMTs Jacob Stilts and Lydia Huse respond to a reported drowning of a child in a backyard swimming pool.
• Initial Findings: Upon arrival, the EMTs observe a female adult performing CPR on a toddler ($2$-year-old female).
• Patient History: Family members report the child was missing for approximately $5$ to $10$ minutes before being discovered at the bottom of the pool. A family member extricated the child and initiated CPR immediately.
• Incident Prevention Considerations: The case prompts a review of how such incidents could be prevented (e.g., fencing) and what factors influence survival probability.

Introduction to Submersion Incidents

• Immediate Care Needs: Patients involved in submersion incidents require rapid emergency medical intervention. However, the environment often presents significant risks to medical personnel.
• Rescuer Safety Requirements: Successful management requires emergency medical skills and the ability to identify, avoid, or mitigate scene hazards.

Water-Related Emergencies: Prevention and Definitions

• Standard Prevention Measures:
  • Utilization of Personal Flotation Devices (PFDs) to prevent drowning deaths.
  • Ensuring all swimming pools are appropriately fenced.
  • Providing constant supervision for children near any body of water or large liquid container.
  • Avoiding alcohol consumption during water-related activities.
• Defining Drowning:
  • An incident characterized by submersion or immersion in a liquid that results in primary respiratory impairment.
  • The liquid physically prevents the patient from breathing air.
  • Outcomes vary; the patient may survive the event or succumb to it.

Epidemiology and Incidence of Drowning

• Childhood Statistics:
  • Drowning is the leading cause of death in children.
  • The most common drowning location for children is the bathtub.
  • For children aged $1\text{--}4$ years, drowning is the leading cause of death, surpassed only by birth defects.
  • Children aged $1\text{--}14$ years represent the second-highest incidence group.
• Demographics and Risk Factors:
  • Approximately $80\%$ of drowning victims are male.
  • Alcohol is a frequent contributing factor in drowning incidents.
  • For individuals with seizure disorders, the bathtub is the most common site for drowning events.
  • Water sports increase the risk of both drowning and traumatic injuries (head and spinal).
  • Panic is a significant contributor to death when a person loses self-control in the water.

Prognostic Predictors and Survival Probability

• Survival Factors: Chances of survival are highest when the patient presents with two or fewer of the following high-risk characteristics:
  • Age $\ge 3$ years.
  • Submersion duration $> 5$ minutes.
  • Resuscitation delayed $> 10$ minutes after rescue.
  • Comatose status upon arrival at the Emergency Department (ED).
  • Arterial blood pH $< 7.10$.

Pathophysiology of Drowning

• Initial Mechanism: Submersion leads to either the aspiration of water or laryngeal spasms, both resulting in suffocation (hypoxia).
• Systemic Effects: Progressive hypoxia and acidosis lead to irreversible brain damage and death.
• Pulmonary Complications:
  • Surfactant Function: Surfactant normally maintains surface tension in the alveoli to prevent collapse.
  • Surfactant Washout: Water entering the lungs washes out the surfactant, causing alveoli to collapse.
  • Resultant Condition: This leads to Acute Respiratory Distress Syndrome (ARDS).
• Physiological Responses:
  • Emergency care aims to maximize oxygen delivery.
  • Submersion in cold water leads to hypothermia, which may exert a protective effect by slowing metabolism.
  • Hypothermia Complications: Includes hypovolemia (due to increased capillary permeability) and cardiac dysrhythmias.
• Factors Influencing Severity:
  • Persistent cough.
  • Dyspnea or apnea.
  • Altered mental status during the submersion event.
  • Vomiting.
  • Drug or alcohol use.
  • History of seizures, diabetes, or neuromuscular disorders.
  • Duration of cardiac or respiratory arrest.
  • Age and pre-existing medical conditions.

Rescue Operations and Safety Measures

• Diving Hazards: Drowning incidents in pools or shallow water often involve head and spine injuries, as well as fractures to the ribs or extremities.
• Rescuer Criteria: Do not attempt a water rescue unless:
  • You are a proficient swimmer.
  • You are specifically trained in water-rescue techniques.
  • You are wearing a PFD.
  • You are accompanied by other rescuers.
• Shore-Based Rescue Strategy: If the patient is near the shore, utilize the hierarchy of Reach, Throw, Row, Go.
  • Use a floating object (tied to a rope and unlikely to break) to pull the patient.
  • Use a boat to reach unresponsive patients to avoid becoming a victim yourself.
• Suspecting Spinal Injury: Immobilization is required if:
  • The incident involves diving or a water slide.
  • The patient was struck by a skier, surfboard, or other object.
  • Intoxication is suspected.
  • There is visible evidence of traumatic injury.
• Mammalian Diving Reflex:
  • May be activated during cold-water drowning.
  • Results in a drastic decrease in metabolic rate.
  • Can allow for successful resuscitation even after prolonged submersion.

Assessment-Based Approach: Drowning

• Scene Size-Up:
  • Maintain rescuer safety.
  • Rescuers within $10$ feet of the water's edge must wear a PFD.
  • Follow Standard Precautions.
  • Note mechanisms of injury and request additional resources.
• Primary Assessment:
  • Form a general impression.
  • Assess mental status.
  • Consider spinal motion restriction (SMR).
  • Establish a patent airway (suction if needed; use head-tilt, chin-lift or jaw-thrust).
  • Provide Positive Pressure Ventilation (PPV) with oxygen for inadequate breathing.
  • Assess circulation (pulses, bleeding, perfusion) and determine transport priority.
• Secondary Assessment:
  • Conduct a physical exam and obtain a history.
  • Signs/Symptoms to monitor: Airway obstruction, pulselessness, shock, hypothermia, drug/alcohol involvement, and soft tissue or musculoskeletal injuries.
• Patient Categorization:
  • Asymptomatic.
  • Symptomatic.
  • Cardiac arrest.
  • Obviously dead.

Emergency Medical Care Protocols

• Immediate Management:
  • Extricate patient safely and quickly.
  • If no spinal injury, place the patient in the lateral recumbent position (on the left side) if they have a pulse and are breathing.
  • Maintain $SpO_{2} \ge 95\%$.
  • If pulseless and apneic, initiate CPR and apply the Automated External Defibrillator (AED).
• Gastric Distention: If it interferes with ventilation, decompress the stomach.
• Hypothermia Management (Core Temperature Thresholds):
  • If body core temperature is $< 93.2^{\circ} F$ ($34^{\circ} C$): Actively rewarm.
  • If body core temperature is $\ge 93.2^{\circ} F$ ($34^{\circ} C$): Passively rewarm.
• Transport Mandate: Always transport drowning patients, even if asymptomatic at the scene. Pulmonary or neurological complications can arise up to $72$ hours post-incident.
• Reassessment Frequency:
  • Unstable patients: Every $5$ minutes.
  • Stable patients: Every $15$ minutes.

Scuba and Deep-Water Diving Physics

• Dysbarism: Medical conditions resulting from pressure changes on gases within the body.
• Boyle’s Law: At a constant temperature, the volume of a gas ($V$) is inversely related to the pressure ($P$) ($P \propto \frac{1}{V}$). As pressure increases, volume decreases; as pressure decreases, volume increases.
• Dalton’s Law: The total pressure of a gas mixture is the sum of the partial pressures of the individual gases ($P_{total} = P_{1} + P_{2} + ... + P_{n}$). During descent, the partial pressure of nitrogen increases, causing it to dissolve into the blood.
• Henry’s Law: At a constant temperature, the amount of gas that dissolves in a liquid is proportionate to the partial pressure of that gas. At depth, gases dissolve into and accumulate in fat and tissues.
• Charles’ Law: All gases expand equally upon being heated. Inhaled gases contract in cold water at depth and expand during ascent as temperature increases.

Decompression Sickness (DCS)

• Pathophysiology: Caused by nitrogen gas bubbles expanding in the blood and tissues during ascent.
• Effects of Bubbles:
  1. Act as emboli obstructing circulation.
  2. Compress or stretch blood vessels and nerves.
• Predisposing Factors:
  • Diving-related: Flying too soon after a dive, lack of safety stops, inadequate surface intervals/decompression, deep/long or repeated dives.
  • Physical: Obesity, age, dehydration, heart/lung disease, exhaustion, or pre-existing musculoskeletal injury.
  • Environmental: Cold water, rough seas, heavy work, or heated diving suits.
• Categories:
  • Type I DCS: Symptoms include pain, pruritus (itching/burning), skin rash, "orange peel" skin appearance, and painless pitting edema.
  • Type II DCS:
    • Nervous System: Low back pain progressing to weakness/paralysis, numbness, tingling, altered mental status, visual disturbances, vertigo, and tinnitus.
    • Circulatory System: Signs of hypovolemic shock and thrombus formation.
    • Respiratory System: Substernal burning on inhalation, nonproductive cough, and respiratory distress.

Arterial Gas Embolism (AGE) and Barotrauma

• Arterial Gas Embolism (AGE):
  • Occurs when an artery is obstructed by air bubbles.
  • Often caused by rapid ascent while holding one's breath, leading to alveolar rupture and air entering the bloodstream.
  • Characterized by a rapid onset of symptoms.
  • Symptoms: Itchy/mottled skin, chest pain, frothy blood in nose/mouth, numbness/paralysis (often unilateral), staggering gait, memory loss, and cardiac arrest.
• Barotrauma: Pressure-induced damage to air-filled cavities (sinuses, middle ear) occurring during ascent or descent.

Emergency Medical Care for Diving Emergencies

• Consider spinal stabilization.
• Maintain patient in a supine or lateral recumbent position.
• Establish airway and provide oxygen or PPV as indicated.
• Initiate CPR/AED if needed and transport immediately.

Case Study Conclusion

• Management: Jacob performs a head-tilt, chin-lift, inserts an oropharyngeal airway, and provides suction. A towel is placed under the child's shoulders to maintain the airway.
• Complications: Lydia applies the AED; no shock is advised. During PPV, the patient develops gastric distention; EMTs roll her to the side to decompress the stomach and prevent aspiration.
• Outcome: Transport involves a $20$-minute window, requiring an Advanced Life Support (ALS) intercept. The patient regains a pulse before reaching the ED but remains unresponsive. Prognosis for recovery from potential neurological and respiratory complications remains uncertain at the time of pediatric critical care admission.