Drowning Summary

Definitions

  • Drowning: Respiratory impairment from submersion/immersion
  • Submersion: Face underwater → rapid asphyxia
  • Immersion: Head above water → hypothermia risk

Pathophysiology

  • Initial breath hold → hypoxia
  • Laryngospasm → temporary protection
  • Reflex abatement → aspiration
  • Hypoxia → bradycardia → cardiac arrest

Water Rescue

  • Reach/throw first, don't enter water
  • Spinal precautions only if trauma suspected
  • Horizontal position during retrieval
  • Submersion time critical for prognosis

Initial Resuscitation

  • 5 initial rescue breaths first
  • Check for agonal breathing
  • Expect foam/regurgitation
  • Standard CPR 30:2 after initial breaths

ALS Modifications

  • High-flow oxygen initially
  • Early intubation for poor response
  • PEEP 5-20 cm H₂O
  • Correct hypovolaemia with IV fluids

Poor Prognosis Factors

  • Submersion >5 minutes
  • Time to BLS >10 minutes
  • GCS <5 in ED
  • pH <7.1 on presentation
  • Age >14 years

Critical Points

  • Ventilation critical for ROSC
  • Continue resuscitation unless clearly futile
  • Consider ECMO in selected cases
  • ARDS common complication

Drowning - Emergency Management

Comprehensive guide to drowning pathophysiology, rescue, and resuscitation

Definitions

Drowning

Defined as a process resulting in primary respiratory impairment from submersion or immersion in a liquid medium. Implicit in this definition is that a liquid/air interface is present at the entrance of the victim's airway preventing the victim from breathing air.

Submersion

Occurs when the face is underwater or covered in water. Asphyxia and cardiac arrest occurs within a matter of minutes of submersion.

Immersion

When the head remains above water, in most cases by means of a life jacket. The victim remains immersed with an open airway and becomes hypothermic, although aspiration may occur if water splashes in the face or if the victim becomes unconscious.

Pathophysiology of Drowning

Sequence of Events
  1. Initial breath hold by reflex, frequently swallows water
  2. Hypoxia and hypercapnia develop as breath holding continues
  3. Reflex laryngospasm may temporarily prevent water entry into lungs
  4. Reflexes abate and victim aspirates water
  5. Bradycardia occurs as consequence of hypoxia
  6. Cardiac arrest follows if not rescued

Critical: Correction of hypoxaemia by ventilation-only resuscitation is critical and in itself may lead to ROSC in some cases.

Water Rescue

Rescue can present significant risk to the rescuer but a sensible risk assessment is necessary to ensure that potentially survivable victims are rescued promptly.

Rescue Principles

Safe Rescue Methods

  • Talk, reach, throw - attempt rescue without water entry
  • Use rescue aids - poles, ropes, floatation devices
  • Take buoyant aid if water entry essential
  • Two rescuers safer than alone

Timing Considerations

  • <10 minutes submersion: Very high chance of good outcome
  • >25 minutes submersion: Low chance of good outcome
  • UK guidelines: Review search at 30-60 minutes (90 minutes for children/icy water)

Special Considerations

  • Spinal precautions: Unnecessary unless history of diving in shallow water, water-slide use, water-skiing, kite-surfing, or signs of severe injury
  • Positioning: Keep victim horizontal during retrieval to prevent cardiovascular collapse from hypovolaemia
  • In-water ventilation: Consider only if delay in reaching land/rescue craft

Initial Resuscitation Once Retrieved

Resuscitation Sequence
  1. Check response by opening airway and check for signs of life
  2. Do not confuse agonal breathing with normal breathing
  3. Give 5 initial rescue breaths supplemented with oxygen if available
  4. If no response to initial ventilations, place on firm surface and start chest compressions
  5. Provide CPR in ratio of 30 compressions to 2 ventilations

Managing Complications

Foam Production

Massive amounts of foam caused by mixing moving air with water and surfactant can sometimes come out of the mouth. If this occurs, continue rescue breaths/ventilation until tracheal intubation can be attempted.

Regurgitation

Regurgitation of stomach contents and swallowed water is common. If this prevents ventilation, turn the victim on their side and remove the regurgitated material using directed suction if possible.

Modifications to ALS After Drowning

Airway and Breathing

Intervention Details
Oxygen High flow (10-15 L/min) through reservoir mask for spontaneously breathing patients
Early Intubation Consider for victims failing basic airway measures, reduced consciousness, or cardiac arrest
Oxygen Titration Aim for SpO₂ 94-98% in non-arrested patients or post-ROSC
PEEP Set to at least 5-10 cm H₂O (15-20 cm H₂O if severely hypoxaemic)
Gastric Decompression Insert gastric tube to decompress stomach

Circulation and Defibrillation

Assessment

  • Palpation of pulse unreliable in wet, cold patients
  • Check ECG and end-tidal CO₂ to confirm cardiac output
  • Follow standard ALS protocols for cardiac arrest
  • Modify approach for hypothermia if present

Interventions

  • Dry chest before applying defibrillator pads
  • Assess rhythm and defibrillate if indicated
  • Give rapid IV fluids for hypovolaemia
  • Commence fluid resuscitation pre-hospital if transfer prolonged

Discontinuing Resuscitation

  • No single factor predicts good or poor survival
  • Continue resuscitation unless clearly futile (massive trauma, rigor mortis)
  • Neurologically intact survival reported after >25 min submersion in ice-cold water (especially children)
  • Timely evacuation to medical facility important consideration

Post-resuscitation Care

Standard Care

  • Follow standard post-resuscitation guidelines
  • Many develop ARDS - use protective ventilation strategies
  • Pneumonia common - consider prophylactic antibiotics after sewage contamination
  • Neurological outcome determined by duration of hypoxia

Advanced Interventions

  • ECMO: Consider for refractory cardiac arrest, refractory hypoxaemia, or ice-cold water submersion
  • Neuroprotective measures: Maintain adequate cerebral perfusion
  • Temperature management: Consider therapeutic hypothermia in selected cases

End Organ Effects of Drowning

System Effects
Pulmonary Noncardiogenic pulmonary oedema, ARDS, Pneumonia
Neurological Cerebral hypoxaemia and ischaemia, Cerebral oedema, Raised ICP, Permanent neurological damage
Cardiovascular Arrhythmias secondary to hypothermia and hypoxaemia
Other Metabolic/respiratory acidosis, Renal failure, Haemolysis and coagulopathy

Prognostic Factors

The following factors at presentation have been associated with a poor prognosis:

Critical Time Factors

  • Duration of submersion >5 minutes (most critical factor)
  • Time to effective BLS >10 minutes
  • Resuscitation duration >25 minutes

Clinical Factors

  • Age >14 years
  • Glasgow coma scale <5 (comatose)
  • Persistent apnea and requirement of CPR in ED
  • Arterial blood pH <7.1 upon presentation

Note: While these factors indicate poor prognosis, no single factor should be used in isolation to terminate resuscitation, especially in cases of cold water submersion in children.