All EMS presentations
EnvironmentalClinical presentation

Submersion / drowning

A streamlined, differential-led presentation for rapid clinical review.

Clinical snapshot

Twenty-second review

  • Submersion causes hypoxemia from airway compromise and impaired gas exchange; aspiration, cold exposure, trauma, and delayed pulmonary injury may follow.
  • Apnea, persistent hypoxia, respiratory distress, altered LOC, hypothermia, or suspected diving or spinal injury requires urgent care.
  • Keep syncope, seizure, intoxication, or trauma in the differential; overlapping or concurrent illness remains possible.
  • For submersion / drowning, trends and combinations of findings are more informative than one isolated vital sign.
Differentials

Compare the clinical patterns

The repeated material is grouped inside each possibility. Open only the condition you need.

Serious2 conditions
Respiratory failureTime-sensitive high-risk possibility

HPI

Clarify estimated submersion time; witnessed; water type/temp.

Signs & symptoms

Persistent hypoxia, crackles, fatigue, apnea, or absent circulation.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Respiratory failure may cause submersion / drowning through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Environmental illness is defined by exposure plus physiology. Temperature, heart rate, pressure, and respiratory rate help grade systemic effect and response to removal or treatment.

Temperature (°C)

High or low

Use an appropriate measurement method for the suspected exposure.

Heart rate (bpm)

May rise or fall

Rate varies with temperature, dehydration, toxicity, and severity.

Blood pressure (mmHg)

May fall

Hypotension suggests dehydration, vasodilation, or advanced illness.

Respiratory rate (breaths/min)

May rise or fall

Respiratory response depends on temperature, inhalation injury, and metabolic state.

Front-load in the triage report

  • Respiratory failure: Persistent hypoxia, crackles, fatigue, apnea, or absent circulation.
  • Estimated submersion time.
  • Witnessed?
Cardiac arrestTime-sensitive high-risk possibility

HPI

Clarify witnessed; water type/temp; initial loc/breathing.

Signs & symptoms

Persistent hypoxia, crackles, fatigue, apnea, or absent circulation.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Assess airway and ventilation, lung sounds, temperature, neurologic status, trauma, duration, water type, and witnessed arrest details.

Brief pathophysiology

Cardiac arrest may cause submersion / drowning through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Absent or nonperfusing observations are expected in arrest. SpO₂ is not a reliable confirmation of circulation; follow the resuscitation or expected-death pathway for the clinical context.

Heart rate (bpm)

Absent / nonperfusing

Confirm a central pulse and rhythm; monitor rate alone does not establish perfusion.

Blood pressure (mmHg)

Unobtainable

An unobtainable pressure is expected without effective circulation.

Respiratory rate (breaths/min)

Absent or agonal

Agonal gasps are not effective breathing.

Oxygen saturation (SpO₂)

Unreliable

Pulse oximetry is unreliable during absent or severely reduced perfusion.

Front-load in the triage report

  • Cardiac arrest: Persistent hypoxia, crackles, fatigue, apnea, or absent circulation.
  • Witnessed?
  • Water type/temp.
Common1 condition
Minor aspiration injuryCommon presentation pattern

HPI

Clarify estimated submersion time; witnessed; water type/temp.

Signs & symptoms

Cough and transient symptoms can occur after brief submersion.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Minor aspiration injury may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.

Vital-sign pattern

What the trend may show

Possible pattern

Respiratory infection may impair oxygenation and trigger systemic illness. Older or immunocompromised patients may lack fever, so trend all four observations and mental status.

Respiratory rate (breaths/min)

Often rises

Tachypnea can be an early marker of respiratory or systemic illness.

Oxygen saturation (SpO₂)

May fall

Parenchymal disease can impair gas exchange; compare with baseline.

Temperature (°C)

May rise or fall

Fever is common, but normal or low temperature does not exclude serious infection.

Heart rate (bpm)

Often rises

Tachycardia may reflect fever, hypoxia, dehydration, or sepsis.

Front-load in the triage report

  • Cough and transient symptoms can occur after brief submersion.
  • Estimated submersion time.
  • Witnessed?
Mimics4 conditions
SyncopeImportant alternative presentation

HPI

Clarify estimated submersion time; witnessed; water type/temp.

Signs & symptoms

A precipitating event may have caused submersion.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Syncope can resemble submersion / drowning through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Environmental illness is defined by exposure plus physiology. Temperature, heart rate, pressure, and respiratory rate help grade systemic effect and response to removal or treatment.

Temperature (°C)

High or low

Use an appropriate measurement method for the suspected exposure.

Heart rate (bpm)

May rise or fall

Rate varies with temperature, dehydration, toxicity, and severity.

Blood pressure (mmHg)

May fall

Hypotension suggests dehydration, vasodilation, or advanced illness.

Respiratory rate (breaths/min)

May rise or fall

Respiratory response depends on temperature, inhalation injury, and metabolic state.

Front-load in the triage report

  • A precipitating event may have caused submersion.
  • Estimated submersion time.
  • Witnessed?
SeizureImportant alternative presentation

HPI

Clarify witnessed; water type/temp; initial loc/breathing.

Signs & symptoms

A precipitating event may have caused submersion.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Assess airway and ventilation, lung sounds, temperature, neurologic status, trauma, duration, water type, and witnessed arrest details.

Brief pathophysiology

Seizure can resemble submersion / drowning through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.

Heart rate (bpm)

Often rises transiently

Autonomic activation commonly causes postictal tachycardia.

Oxygen saturation (SpO₂)

May fall transiently

Apnea, obstruction, or hypoventilation can lower saturation.

Blood glucose (mmol/L)

Check early

Hypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.

Temperature (°C)

May rise

A brief rise may follow seizure; fever raises concern for infection or a provoking illness.

Front-load in the triage report

  • A precipitating event may have caused submersion.
  • Witnessed?
  • Water type/temp.
IntoxicationImportant alternative presentation

HPI

Clarify water type/temp; initial loc/breathing; arrest/cpr.

Signs & symptoms

A precipitating event may have caused submersion.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Assess airway and ventilation, lung sounds, temperature, neurologic status, trauma, duration, water type, and witnessed arrest details.

Brief pathophysiology

Intoxication can resemble submersion / drowning through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Environmental illness is defined by exposure plus physiology. Temperature, heart rate, pressure, and respiratory rate help grade systemic effect and response to removal or treatment.

Temperature (°C)

High or low

Use an appropriate measurement method for the suspected exposure.

Heart rate (bpm)

May rise or fall

Rate varies with temperature, dehydration, toxicity, and severity.

Blood pressure (mmHg)

May fall

Hypotension suggests dehydration, vasodilation, or advanced illness.

Respiratory rate (breaths/min)

May rise or fall

Respiratory response depends on temperature, inhalation injury, and metabolic state.

Front-load in the triage report

  • A precipitating event may have caused submersion.
  • Water type/temp.
  • Initial LOC/breathing.
TraumaImportant alternative presentation

HPI

Clarify initial loc/breathing; arrest/cpr; rosc time.

Signs & symptoms

A precipitating event may have caused submersion.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Assess airway and ventilation, lung sounds, temperature, neurologic status, trauma, duration, water type, and witnessed arrest details.

Brief pathophysiology

Trauma can resemble submersion / drowning through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Environmental illness is defined by exposure plus physiology. Temperature, heart rate, pressure, and respiratory rate help grade systemic effect and response to removal or treatment.

Temperature (°C)

High or low

Use an appropriate measurement method for the suspected exposure.

Heart rate (bpm)

May rise or fall

Rate varies with temperature, dehydration, toxicity, and severity.

Blood pressure (mmHg)

May fall

Hypotension suggests dehydration, vasodilation, or advanced illness.

Respiratory rate (breaths/min)

May rise or fall

Respiratory response depends on temperature, inhalation injury, and metabolic state.

Front-load in the triage report

  • A precipitating event may have caused submersion.
  • Initial LOC/breathing.
  • Arrest/CPR.
Red flags

Findings that should escalate concern

  • Apnea, persistent hypoxia, respiratory distress, altered LOC, hypothermia, or suspected diving or spinal injury requires urgent care.
  • Respiratory failure or cardiac arrest: Persistent hypoxia, crackles, fatigue, apnea, or absent circulation.
Related EMS presentations

Continue the clinical pathway

NeurologicSeizureTraumaHead injuryCardiacCardiac arrest / ROSCRespiratoryChoking / airway foreign bodyEnvironmentalHeat / cold exposure
References

Clinical and academic sources

Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.

BCEHS Handbook — specific CPGs

  1. H12: DrowningBC Emergency Health Services Handbook

    Official BCEHS clinical practice guidance for drowning.

Supporting clinical and academic evidence

  1. CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians

    Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.

  2. Clinical Practice Guideline SummariesWilderness Medical Society

    Evidence-based guidance for environmental and wilderness emergencies, including heat, cold, altitude, and drowning.

  3. 2024 AHA/AAP Focused Update: Resuscitation Following DrowningCirculation · 2024

    Ventilation-first drowning resuscitation, oxygenation, hypothermia, and post-resuscitation considerations.