Overview
Drowning
Topic Overview
Summary
Drowning is respiratory impairment from submersion or immersion in liquid. It is a leading cause of accidental death worldwide, especially in children. The primary insult is hypoxia from aspiration and laryngospasm. Management focuses on oxygenation, ventilation, and treating hypothermia. Outcomes depend on submersion time and neurological status. "Secondary drowning" is a misnomer — patients who aspirate may develop delayed pulmonary oedema.
Key Facts
- Definition: Respiratory impairment from submersion/immersion (WHO)
- Primary injury: Hypoxia (aspiration, laryngospasm)
- Treatment: BLS/ALS, oxygenation, rewarming if hypothermic
- Prognosis: Depends on submersion time and GCS at presentation
- Hypothermia: May be protective — continue resuscitation until rewarmed
Clinical Pearls
"You're not dead until you're warm and dead" — prolonged resuscitation in hypothermic drowning
Fresh vs salt water makes little clinical difference — treat hypoxia the same
Children can survive prolonged submersion in cold water — continue resuscitation
Why This Matters Clinically
Drowning is common and preventable. Rapid bystander CPR and early oxygenation saves lives. Cold water submersion can have miraculous recoveries even after prolonged submersion.
Visual Summary
Visual assets to be added:
- Drowning pathophysiology diagram
- Rescue and resuscitation algorithm
- Hypothermia rewarming methods
- Prognostic factors table
Epidemiology
Incidence
- 236,000 deaths/year worldwide (WHO)
- 3rd leading cause of unintentional injury death globally
- 10x higher in low/middle-income countries
Demographics
- Children (peak age 1-4 years: pools/bathtubs)
- Young males (risk-taking behaviour)
- Elderly (medical events in water)
Risk Factors
| Factor | Notes |
|---|---|
| Age | Children under 5, adolescents |
| Male sex | Higher risk-taking |
| Alcohol/drugs | Common in adults |
| Seizures | Risk in bathtub/pool |
| Inability to swim | |
| Unsupervised water access |
Pathophysiology
Mechanism
- Submersion → panic, breath-holding
- Aspiration of water (or laryngospasm → "dry drowning")
- Hypoxia → cardiac arrest
- Multi-organ injury from hypoxia
Pulmonary Effects
- Aspiration → disrupts surfactant
- Alveolar collapse, V/Q mismatch
- Pulmonary oedema (non-cardiogenic)
- ARDS
Fresh vs Salt Water
- Historically different mechanisms described
- Clinically: No significant difference in management or outcome
- Both cause surfactant dysfunction and alveolar damage
Hypothermia
- Cold water rapidly cools body
- May be protective (reduces metabolic demand)
- Allows prolonged resuscitation
"Secondary Drowning"
- Misnomer (ILCOR discourages term)
- Refers to delayed pulmonary oedema hours after aspiration
- All symptomatic patients should be observed
Clinical Presentation
Symptoms
Signs
Severity Spectrum
| Severity | Features |
|---|---|
| Mild | Cough, no respiratory distress |
| Moderate | Dyspnoea, crackles, normal SpO2 on O2 |
| Severe | Respiratory failure, reduced GCS |
| Cardiac arrest | No pulse |
Red Flags
| Finding | Significance |
|---|---|
| Altered GCS | Hypoxic brain injury |
| Cardiac arrest | Critical |
| Hypothermia | Continue resuscitation |
| Persistent hypoxia | May develop ARDS |
Coughing, choking
Common presentation.
Dyspnoea
Common presentation.
Vomiting
Common presentation.
Confusion
Common presentation.
Loss of consciousness
Common presentation.
Clinical Examination
Vital Signs
- SpO2 (often low)
- Temperature (hypothermia)
- Heart rate, BP
Respiratory
- Crackles, wheeze
- Reduced breath sounds
- Signs of aspiration
Neurological
- GCS
- Pupil response
- Focal signs (if associated trauma)
Trauma Assessment
- C-spine (diving injury)
- Other injuries
Investigations
Blood Tests
| Test | Purpose |
|---|---|
| ABG | Hypoxia, acidosis |
| FBC, U&E | Baseline |
| Glucose | May be low |
Imaging
| Modality | Indication |
|---|---|
| CXR | Pulmonary oedema, aspiration |
| CT head | If reduced GCS, suspected hypoxic brain injury |
| C-spine imaging | If diving injury or trauma suspected |
Other
- ECG (arrhythmias)
- Core temperature (hypothermia)
Classification & Staging
WHO Definition
- Drowning: Process of respiratory impairment from submersion/immersion
- Outcome: Death, morbidity, or no morbidity
No Longer Recommended Terms
- "Near-drowning" (ambiguous)
- "Dry drowning" (misnomer)
- "Secondary drowning" (misnomer)
Management
Pre-Hospital Rescue
| Priority | Action |
|---|---|
| Safety | Rescuer safety first |
| Remove from water | Horizontal if possible |
| BLS | Start immediately if no signs of life |
| Open airway | Assume aspiration |
| Rescue breaths | Prioritise oxygenation |
| CPR | Standard ratio 30:2 |
Hospital Management
Oxygenation — Priority:
- High-flow oxygen
- CPAP/BiPAP if respiratory distress
- Intubation if GCS under 8 or severe hypoxia
Ventilation:
- PEEP to recruit collapsed alveoli
- Lung-protective ventilation if ARDS
Hypothermia:
- Core temperature measurement
- Rewarm (active external and internal methods)
- Continue CPR until core temp over 32°C
Cardiac Arrest:
- Standard ALS with modifications
- Prolonged resuscitation if hypothermic
- Consider ECMO if available
Observation
- All symptomatic patients: Observe 6-8 hours minimum
- If asymptomatic with normal SpO2 at 6 hours: Safe to discharge
C-Spine Precautions
- If diving injury or mechanism suggests trauma
- Immobilise until cleared
Complications
Acute
- ARDS
- Hypoxic brain injury
- Arrhythmias
- Aspiration pneumonia
- Death
Late
- Neurological sequelae
- Chronic lung disease (rare)
Prognosis & Outcomes
Prognostic Factors
| Factor | Better Prognosis |
|---|---|
| Short submersion time | Under 5 minutes |
| Cold water | Protective |
| Early bystander CPR | Improves survival |
| Reactive pupils at ED | Better neurological outcome |
Mortality
- Overall 10-20% in hospitalised patients
- Much higher if cardiac arrest before arrival
Neurological Outcome
- Related to hypoxia duration
- Hypothermia may be protective
Evidence & Guidelines
Key Guidelines
- ILCOR (International Liaison Committee on Resuscitation) Guidelines
- Resuscitation Council UK Guidelines
Key Evidence
- Early bystander CPR improves survival
- Prolonged resuscitation in hypothermia is indicated
Patient & Family Information
What is Drowning?
Drowning is when someone has difficulty breathing after being in water. It can range from mild coughing to cardiac arrest.
Warning Signs After Being in Water
- Persistent coughing
- Difficulty breathing
- Confusion
- Chest pain
When to Seek Help
- Anyone who has been underwater and is unwell should go to hospital
- Call 999 immediately if someone is unconscious
Prevention
- Supervise children around water at all times
- Learn to swim
- Don't drink alcohol around water
Resources
References
Primary Guidelines
- Szpilman D, et al. Drowning. N Engl J Med. 2012;366(22):2102-2110. PMID: 22646632
- Resuscitation Council UK. Advanced Life Support Guidelines. 2021. resus.org.uk
Key Reviews
- Bierens JJLM, et al. Drowning. Curr Opin Crit Care. 2019;25(6):583-590. PMID: 31503065