Submersion injury

Background

• Definition: "The process of experiencing respiratory impairment from submersion/immersion in liquid"
  • Term "near-drowning" no longer used

Consider Secondary Causes

• Ethanol intoxication
• Syncope
• Cardiac arrhythmia
• ACS
• Non-accidental trauma

Drowning Outcomes by Duration

Duration of submersion	Risk of death or poor outcome
0–5 min	10%
6–10 min	56%
11–25 min	88%
>25 min	nearly 100%

^Signs of brain-stem injury predict death or severe neurological consequences

Pathophysiology

• Submersion → voluntary breath holding → aspiration → coughing/laryngospasm → aspiration continues → hypoxia → death
• Aspiration destroys surfactant which → alveolar collapse, atelectasis, non-cardiogenic pulmonary edema, and V-Q mismatch.
• Fresh vs salt water has no clinical relevance

Clinical Features

• Pulmonary
  • Hypoxemia due to aspiration
  • Hypoxemia varies with severity but may be seen even with small volume aspiration (1-3mL) due to interference with alveolar gas exchange
  • Shortness of breath
  • Crackles
  • Wheezing
  • May progress to pulmonary edema or ARDS despite adequate ventilation
• Neurologic
  • System most susceptible to hypoxemia
  • Cerebral edema
  • Elevated ICP
  • Severity worsened with prolonged hypoxia
• Cardiovascular
  • Hypoxemia and hypothermia may cause arrhythmias
  • Sinus tachycardia, sinus bradycardia, a-fib
• Metabolic
  • Respiratory / metabolic acidosis
  • Electrolyte disturbances are uncommon but may be seen with submersion in media with unusually high electrolyte concentrations (such as the dead sea)
• Hypothermia

Differential Diagnosis

Water-related injuries

• Hypothermia
• Immersion pulmonary edema
• Marine toxins, envenomations, and bites
• Scuba diving emergencies
• Submersion injury (drowning and near-drowning)

Evaluation

Workup

• CXR (on arrival and after 4 hours)
• ABG - lactic acidosis
• Serum sodium does not correlate to fresh water vs. salt water drowning
• Other work-up generally not needed unless specifically indicated by history or exam, but may consider:
  • Labs, EKG
  • CT head/C-spine (if history of trauma) - C-spine injury extremely unlikely without evidence or history of trauma (<0.5% in large cohort study)

Diagnosis

• Typically a clinical diagnosis

Classification

Grade	Presentation	Recommended Treatment	Survival
0	Responds normally, lungs clear to auscultation, no cough	Do not transport	100%
1	Responds normally, lungs clear to auscultation, has a cough	Discharge	100%
2	Responds normally, rales in some lung fields, has a cough	Nasal cannula, observe in ED	99.4%
3	Responds normally, rales in all lung fields, has a cough, normotension	Non-rebreather, progress to positive pressure or intubation if needed, admit	94.8%
4	Responds normally, rales in all lung fields, has a cough, hypotension	Non-rebreather with likely progression to positive pressure or intubation, IV fluids and pressors as needed, admit to ICU	~80%%
5	Unresponsive but has a pulse	Positive pressure ventilation with likely progression to intubation, IV fluids and vasopressors if needed, admit to ICU	~60%
6	Unresponsive with no pulse after 5 rescue breaths	ACLS protocol	7%

Management

Prehospital

• Immediate resuscitation if indicated
• Assess need for CPR but do not delay removal from water
• Ventilation is a higher priority in drowning victims in cardiac arrest than in other situations requiring CPR
• Deliver two rescue breaths immediately upon reaching shallow water or a stable surface; early breaths have been associated with improved survival
• If no response to rescue breaths with chest rise, continue to standard CPR algorithm
• Administer high flow O2 and intubate apneic patients
• Do not routinely immobilize c-spine without suspicion based on mechanism or clinical signs

Emergency Department

• Supportive care based on presentation is cornerstone of management
• Consider CPAP if inadequate tidal volume with high flow O2
• OG tube for gastric distension
• Indications for intubation:
  • Comatose or unable to protect airway
  • Hypoxemia or hypercapnia on ABG despite high flow O2 (PaO2 below 60, PaCO2 above 50)
• Continue resuscitation efforts in hypothermic patients until core temperature rises to at least 30 C (not dead until warm and dead)
• Routine antibiotics in ED are not necessary, but broad spectrum coverage may be indicated for submersion in heavily contaminated water

Disposition

• Discharge after 4-6 hours of observation if:
  • Normal mental status, SpO2 >95% on room air, normal CXR and respiratory exam
• Admit all others

See Also

• Water-related injuries
• Immersion pulmonary edema