Drowning Submersion Injuries

Introduction

Drowning and submersion injuries are critical topics for MCCQE1 preparation, especially given Canada's abundant water resources and the prevalence of water-related activities. This comprehensive guide will help Canadian medical students understand the key concepts, management strategies, and Canadian-specific considerations for drowning and submersion injuries.

Epidemiology in Canada

Understanding the Canadian context of drowning is crucial for MCCQE1 preparation:

• Drowning is the third leading cause of unintentional injury death in Canada, after motor vehicle collisions and poisoning.
• In Canada, approximately 450-500 people die from drowning each year.
• Males account for about 80% of drowning fatalities in Canada.
• Children aged 1-4 and young adults aged 15-34 are at highest risk.

Pathophysiology

Understanding the pathophysiology of drowning is essential for MCCQE1 success:

Clinical Presentation

For MCCQE1 preparation, be familiar with the spectrum of clinical presentations:

1. Mild: Cough, tachypnea
2. Moderate: Respiratory distress, altered mental status
3. Severe: Respiratory failure, cardiac arrest, coma

Management

Canadian emergency medicine protocols for drowning management follow these key steps:

1. Rescue and Resuscitation:

   • Ensure scene safety
   • Remove victim from water
   • Start CPR if necessary (C-A-B sequence)

2. Oxygenation and Ventilation:

   • Provide high-flow oxygen
   • Consider intubation for severe cases

3. Rewarming (for cold water drowning):

   • Active external rewarming
   • Warm IV fluids

4. Supportive Care:

   • Fluid resuscitation
   • Electrolyte management
   • Seizure control if needed

5. Monitoring and Disposition:

   • Continuous cardiac monitoring
   • Frequent neurological assessments
   • ICU admission for moderate to severe cases

Canadian Guidelines for Drowning Prevention

The Canadian Red Cross and Lifesaving Society provide key guidelines for drowning prevention:

1. Supervision: Always supervise children around water
2. Barriers: Install four-sided fencing around home pools
3. Education: Promote swimming lessons and water safety education
4. Legislation: Support and enforce boating safety laws
5. Rescue equipment: Ensure availability of rescue equipment at public swimming areas

Special Considerations in Canadian Context

1. Cold Water Drowning:

   • More common in Canada due to colder climate
   • Can lead to rapid hypothermia
   • May have protective effect on the brain (slows metabolism)

2. Ice Safety:

   • Unique risk in Canadian winters
   • Educate patients on ice thickness safety guidelines

3. Northern and Remote Communities:

   • Limited access to advanced medical care
   • Importance of community-based prevention and first aid training

Key Points to Remember for MCCQE1

• Drowning is a leading cause of unintentional injury death in Canada
• Males and young children are at highest risk
• Initial management focuses on oxygenation and ventilation
• Cold water drowning requires special attention to rewarming
• Prevention strategies are crucial in Canadian public health approach
• Be familiar with the spectrum of clinical presentations and appropriate management
• Understand the pathophysiology and multisystem effects of drowning

Sample Question

A 6-year-old boy is brought to the emergency department after being found submerged in a backyard pool. He was pulled out immediately and CPR was started. On arrival, he is unresponsive with agonal respirations. His vital signs are: HR 130/min, BP 80/50 mmHg, RR 8/min, Temp 35°C, O2 Sat 85% on room air. Which one of the following is the most appropriate next step in management?

• A. Administer intravenous antibiotics
• B. Perform chest compressions
• C. Intubate and provide mechanical ventilation
• D. Administer intravenous fluids
• E. Initiate therapeutic hypothermia

Explanation

The correct answer is:

• C. Intubate and provide mechanical ventilation

This patient presents with severe drowning injury, evidenced by unresponsiveness, agonal respirations, and hypoxia. The most critical initial step is to secure the airway and provide adequate oxygenation and ventilation. Intubation and mechanical ventilation will address the patient's respiratory failure and hypoxemia.

A. Antibiotics are not the immediate priority and are only considered if aspiration pneumonia develops later. B. Chest compressions are not indicated as the patient has a pulse (HR 130/min). D. While fluid resuscitation may be necessary, securing the airway takes precedence. E. Therapeutic hypothermia is not routinely recommended for drowning victims and would not be the most appropriate next step.

This question tests the candidate's ability to prioritize management steps in a critical drowning scenario, which is crucial for MCCQE1 preparation in emergency medicine.

References

1. Canadian Red Cross. (2021). Drowning Research: Canada's Drowning Report. https://www.redcross.ca/training-and-certification/swimming-and-water-safety-tips-and-resources/drowning-research (opens in a new tab)

2. Lifesaving Society Canada. (2020). Canadian Drowning Report. https://www.lifesaving.ca/cdr/ (opens in a new tab)

3. Szpilman, D., Bierens, J. J., Handley, A. J., & Orlowski, J. P. (2012). Drowning. New England Journal of Medicine, 366(22), 2102-2110.

4. Topjian, A. A., Berg, R. A., Bierens, J. J., Branche, C. M., Clark, R. S., Friberg, H., ... & Morley, P. T. (2020). Brain resuscitation in the drowning victim. Neurocritical care, 33(3), 714-740.

5. Mott, T. F., & Latimer, K. M. (2016). Prevention and treatment of drowning. American family physician, 93(7), 576-582.

6. Paediatric & Child Health Division, The Royal Australasian College of Physicians (RACP). (2015). Policy on drowning prevention. Journal of Paediatrics and Child Health, 51(1), 108-110.