Drowning

See Also

Marine Injury

Definitions

Drowning (WHO Definition)
1. Respiratory Impairment from Submersion or immersion in liquid, which obstructs the victim from breathing air
2. Further classified into fatal or nonfatal (replaces Near-drowning)
3. Avoid antiquated terms such as dry Drowning (laryngospasm, but no fluid aspirated into lungs)

Epidemiology

Deaths per year
1. Worldwide: 140,000-300,000
2. United States: 4,000 to 8,000 per year (roughly 50% of total Drownings)
Incidence peaks May to August in United States
Males account for 80% of Drowning deaths
Most cases in age <14 years old in the United States
1. Age 1-4 most commonly drown in home swimming pools
2. Teens over age 15 years most commonly drown in rivers, lakes or ocean

Causes

Home pools (50% of Drowning cases in United States)
1. Age under 5 years accounts for 90% of cases
Bathtub
1. Second most common site for preschool Drowning cases
2. Majority ages 7 to 15 months old
Occupations
1. Fishing industry (especially Alaska)
Personal Water Craft (e.g. Seadoo)
1. Relative Risk (compared with other boats): 8.5
2. References
  1. Branche (1997) JAMA 278(8):663-5 [PubMed]
Alcohol and Illicit Drugs
1. Involved in over 50% adolescent Drowning cases
Developmental or neurologic Impairment
Epilepsy
Rural Hazards
1. Ponds
2. Ditches
3. Old septic tanks
4. Water filled buckets
  1. Accounts for 24% of preschool Drowning cases
  2. Toddlers unable to right themselves
Physical Abuse
1. Accounts for 8% of childhood Drowning cases
2. References
  1. Gillenwater (1996) Arch Pediatr Adolesc Med 150:298 [PubMed]

Risk Factors

Home pool childproofing lacking
Age younger than 4 years old or in teenage years
Male gender (80% of Drowning)
Non-white
Unable to swim
Adult supervision lacking
No life jacket use
Alcohol or drug use
Risk taking behavior
Cardiac events
Seizure Disorder
Developmental Disorder

Mechanism

Patient struggles to stay above water and hold breath as they submerge
1. Ultimately a breath is taken with subsequent laryngospasm or aspiration
Aspirated water disrupts alveolar-capillary membrane
1. Even small amounts of aspirated water (1 to 3 ml/kg) are enough to trigger ARDS
2. Results in Atelectasis, surfactant loss and Ventilation-Perfusion Mismatch (V-Q Mismatch)
3. Leads to proinflammatory Cytokine release, Neutrophil recruitment and further lung injury
4. Causes ARDS, severe hemorrhagic Pulmonary Edema and bronchospasm
5. Asphyxia and Hypoxemia lead to Metabolic Acidosis, Cardiac Dysrhythmia, brain injury, multisystem failure
6. Cardiac rhythm degenerates over minutes from Tachycardia to Bradycardia to PEA to Asystole
Dry Drownings on autopsy (no lung water): 10-20%
Small-moderate amount water aspirated (<22 ml/kg): 85%
Freshwater and Saltwater Drownings are treated the same
1. Both fresh and saltwater in alveoli cause surfactant dysfunction
Cold water Drownings trigger one of two reflexes
1. Cold Shock reflex
  1. Triggered by a rapid drop in skin Temperature (typically below 25 C or 77 F)
  2. Gasping and Hyperventilation drive increased sympathetic activity, Tachycardia and Cardiac Output (CO)
  3. Increased oxygen demand results in oxygen deficit, loss of airway control and aspiration
2. Mammalian dive reflex
  1. Water Temperature must be 6 C (42.8 F) or colder to induce rapid body cooling
  2. Triggered by activation of Trigeminal Nerve receptors in the nares when they contact cold water
  3. Results in apnea, Bradycardia and decreased Cardiac Output, and peripheral Vasoconstriction
  4. Decreased oxygen demand and increased Oxygen Delivery to vital organs (including the brain)
  5. Decreased oxygen deficits and decreased aspiration risk

Evaluation
First Responders

Move patient immediately to land and position supine
1. In-water Resuscitation (ventilations) only if rescuer is skilled in that technique
Start bystander CPR without delay
1. Outcomes are best with immediate initiation of high quality CPR
Apply AED when available (and on a relatively dry surface)
Remove wet clothing and apply dry towels, blankets and other methods of rewarming

Evaluation
No response to verbal or tactile stimuli (prehospital EMS)

Ventilations are performed first instead of compressions (ABC instead of CAB)
Open airway and check for ventilations
1. No breathing
  1. Give 5 initial breaths
  2. Check carotid pulse
2. Breathing
  1. Lung auscultation (see protocol below)
  2. Place in recovery position (left lateral decubitus)
Pulse absent
1. Submersion >1 hour or signs of death
  1. Survival probability: 0%
  2. Pronounce patient and cease efforts
2. Submersion <1 hour and no signs of death (Grade 6)
  1. Initiate CPR with high quality Chest Compressions (100-120/min)
  2. Apply AED or Defibrillator pads when available (most commonly in Asystole or PEA)
  3. Move to Grade 5 or 4 management (if ROSC achieved)
  4. Survival probability: 7-12%
Pulse present (Grade 5)
1. Rescue Breathing until return of spontaneous ventilation or Mechanical Ventilation
2. Chest Compressions (and epinephine, Atropine) if Heart Rate <60/min in a young child (Unstable Bradycardia)
3. Move to grade 4 management
4. Admit to medical ICU
5. Survival probability: 56-69%

Evaluation
Responds to verbal or tactile stimuli (prehospital EMS)

Abnormal breath sounds
1. Rales in all pulmonary fields
  1. General management
    1. High Flow Oxygen via Face Mask
    2. Intubate for GCS 8 or less, Respiratory Failure or other Advanced Airway indications
    3. Admit to medical ICU
  2. Hypotension or shock (Grade 4)
    1. Risk of delayed respiratory arrest
    2. Fluid Resuscitation with crystalloid and consider Vasopressors
    3. Survival probability: 78-82%
  3. Normal Blood Pressure (Grade 3)
    1. Survival probability: 95-96%
2. Rales in some pulmonary fields (Grade 2)
  1. Low Flow Oxygen
  2. Transfer to emergency department
  3. Survival probability: 99%
Normal breath sounds (94% of lifeguard rescues)
1. Cough (Grade 1)
  1. Further evaluation as needed
  2. Survival probability: 100%
2. No cough (Rescue)
  1. No comorbid conditions and asymptomatic
  2. May be discharge from accident scene

HIstory

See SAMPLE History
Timing
1. Total estimated water Submersion time
2. Time from removal from water to first Resuscitation attempt
Field Resuscitation Efforts
1. CPR and other interventions
2. Cardiac Rhythm
3. Bedside Glucose
Water Conditions
1. Water Temperature (i.e. cold water Drowning?)
2. Water contaminants (e.g. sewage)
3. Fresh water or salt water may impact the organisms causing Aspiration Pneumonia
Events prior to Drowning
1. Trauma (e.g. diving injury, scuba Barotrauma)
2. Nonaccidental Trauma concerns
3. Suicidality prior to Drowning
4. Intentional Overdose
5. Alcohol Intoxication or drug Intoxication
6. Hypoglycemia
7. Seizures

Findings

Mild cough may be present
1. Does not distinguish benign from complicated course
Serious findings (among the indications for hospital admission)
1. Hypoxemia
2. Increased work of breathing
3. Dyspnea
Ominous findings
1. Abnormal lung findings on asucultation
2. Severe cough
3. Frothy Sputum
4. Foamy material in airway
5. Hypotension

Imaging

Chest XRay
1. Initial XRay is typically normal (ARDS findings delayed)
  1. Do not anchor on an initial normal Chest XRay
  2. Progression to Respiratory Failure after first negative Chest XRay does occur
2. Pulmonary Edema
3. Pneumothorax
4. Pneumomediastinum
Head CT
1. Indicated in Altered Level of Consciousness or concerns for Head Trauma
2. Abnormal initial Head CT is associated with worse prognosis
3. Normal initial Head CT may be followed by subsequent brain edema and findings of hypoxic brain injury
4. CPR does not appear to cause Hemorrhage on Head CT (assume Head Trauma or other CNS Hemorrhage causes)
5. Rafaat (2008) Pediatr Crit Care Med 9(6): 567-72 [PubMed]
CT Cervical Spine
1. Not routinely indicated
2. Consider in diving injury, or multi-system Trauma accident (e.g. boating), or signs of head or neck Trauma

Diagnostics

Electrocardiogram (EKG)

Labs

Arterial Blood Gas or Venous Blood Gas
1. Initial pH <7.10 is associated with worse prognosis
Complete Blood Count
Comprehensive Metabolic Panel (rarely abnormal)
Coagulation Studies (INR, PTT, rarely abnormal)
Pregnancy Test (if indicated)
Toxicology Screening (if indicated)
1. Blood Alcohol Level
2. Urine Drug Screen
3. Acetaminophen level
4. Salicylate level

Management
Initial

Accident site
1. Do NOT clear airway of aspirated water
  1. Delays ventilation
  2. Use Heimlich/Abdominal thrust ONLY IF obstruction
2. Cervical Spine precautions
  1. Controversial unless diving or other injury with suspected C-Spine Injury
  2. Cervical Spine injuries occur in <1% of Drowning cases
3. Rescue Breathing and CPR
  1. Ventilation is paramount and should be started while still in water (if skilled in technique)
  2. Start with 5 ventilations and then every 6-8 seconds until on land
  3. Chest Compressions obviously are delayed until on land at which time initiate 2 breaths per CPR cycle
4. Keep patient horizontal to maximize brain perfusion
Initial ACLS management
1. ACLS protocol
2. Continue Resuscitation efforts until ROSC or if pulseless, until efforts are assumed futile
  1. Continue CPR until patient is rewarmed (see Hypothermia as below)
  2. Continue CPR for at least 30 minutes in a normothermic patient (based on pediatric data)
3. Respiratory management is paramount
  1. Optimize oxygenation and ventilation
  2. Monitor respiratory effort and Oxygen Saturation
    1. Maintain Oxygen Saturation 94% and higher
    2. Even initially asymptomatic patients may decompensate to ARDS
    3. Supraglottic Airways may be inadequate (high airway resistance, low Lung Compliance)
    4. Typical Airway Suctioning as needed (but do not attempt suctioning of aspirated water)
  3. Non-Invasive Positive Pressure Ventilation for conscious patients
    1. Move to intubation if not improving in first 10-30 minutes
  4. Intubation indications
    1. Apnea
    2. PaO2 <60 mmHg or Oxygen Saturation <90% despite Oxygen Supplementation
    3. PaCO2 >50 mmHg
    4. Unconscious patient or neurologic deterioration
    5. Unable to protect airway
  5. Mechanical Ventilation
    1. Use ARDS guidelines with Lung Protective Ventilator Strategy
    2. Use lower Lung Volume (6-8 L/kg Ideal Weight) and plateau pressure <30 mmHg
    3. Optimize PEEP and titrate down Oxygen Saturation to 90 to 95%
4. Cardiovascular management
  1. Optimal airway and breathing management prevents Arrhythmia progression
  2. Drowning, Hypoxia and acidosis lead to Sinus Tachycardia, Bradycardia and then PEA and Asystole
    1. Ventricular Tachycardia and Ventricular Fibrillation are uncommon following primary Drowning
5. C-Spine precaution indications
  1. Altered Level of Consciousness or intoxicated
  2. Head, face, neck Trauma findings
  3. History consistent with neck injury (e.g. diving or boating accident, fall from height, multi-Trauma findings)
6. Observation for Vomiting and aspiration risk
  1. Occurs in 30-85% of Drowning victims who swallow large water volumes
7. Hypotension
  1. Persistent Hypotension is associated with worse outcomes
    1. However excessive fluid Resuscitation may worsen Pulmonary Edema and ARDS
    2. Hypotension is typically due to cardiac dysfunction rather than Hypovolemia
  2. Initiate Vasopressors early in combination with careful use of Intravenous Fluids
8. Hypothermia
  1. Cold water Drownings may be protective of neurologic status
    1. Water Temperature must be 6 C (42.8 F) or colder to induce rapid body cooling for neuroprotection
    2. Drowning victims are "not dead unless warm and dead"
    3. Cerebral oxygen (and ATP) consumption drops by 5% per every 1 C below 37C
    4. Cerebral oxygen (and ATP) consumption drops 50% when core Temperature 27C
      1. Core Temperature of 27C (10C drop from 37C) doubles brain survival time
  2. Mild Hypothermia (Brief immersion in warm water with Body Temp 32-35C or 89.6-95F)
    1. Initiate rewarming en route to facility
  3. Moderate to Severe Hypothermia (T <32C or 89.6F) - Most cases
    1. See Hypothermia Management
    2. Passive Rewarming may be started in field
    3. Initiate active rewarming at medical facility
9. Empiric Antibiotics are not typically indicated
  1. Consider if grossly contaminated water
  2. Gram Stain and culture directed Antibiotics are preferred over empiric, prophylactic Antibiotics
10. Exposure
  1. Remove wet clothing and perform Trauma Exam to evaluate for other injuries
Medical facility management
1. Continue ACLS protocol
2. Reevaluate airway and consider intubation (see indications above)
3. Emergency Neurologic Exam including Glasgow Coma Scale
4. Nasogastric Tube (decompress swallowed water)
5. Evaluate C-Spine for suspected injury (if high risk mechanism such as diving)
6. Freshwater and Saltwater Drownings are treated the same
7. Core Rewarming (for severe Hypothermia)
  1. Avoid drugs or stimuli that can trigger Ventricular Fibrillation
  2. Administer warm humidified oxygen endotracheally
  3. Administer warm fluid by central IV
  4. Peritoneal or Chest Tube lavage
  5. Esophageal rewarming tube
  6. Cardiopulmonary bypass or Extracorporeal Membrane Oxygenation (ECMO)
  7. Continue Resuscitation efforts until core Temperature 34-35C (or 93.2 to 95C)
8. ECMO Indications
  1. Severe Hypoxemia and poor Lung Compliance despite optimized Mechanical Ventilation
  2. Severe Hypothermia (<28 C)

Management
Disposition

Criteria for early discharge from ED after 8 hours observation (Grade 1, benign cases only)
1. Children and young adults AND
2. Normal age adjusted Vital Signs and examination including Oxygen Saturation >94% AND
3. No symptoms (mild cough may be an exception) AND
4. No preexisting Neurologic or cardiopulmonary disease AND
5. GCS 14 or 15
Criteria for routine hospital ward observation for 24 hours
1. Patients with minimal symptoms (mild cough) AND
2. Normal Oxygen Saturation
Criteria for ICU admission
1. Above criteria not met
2. Any signs of respiratory distress
References

Management
Discharge

Indications
1. See early ED discharge indications as above (Grade 1, benign cases only)
Precautions
1. Observe at least 6 to 8 hours after non-Fatal Drowning
  1. Decompensation at 7 hours has been observed in initially asymptomatic patients
Approach
1. Prophylactic Antibiotics are NOT indicated
2. Discharge Instructions
  1. Delayed respiratory distress and infection precautions
  2. Close interval follow-up
  3. Review Drowning prevention (see below)

Management
ICU

Monitoring
1. Continuous O2 Sats and frequent lung auscultation
2. Urine Output
3. Electrolytes and Glucose
4. CXR
5. ABG
Specific Management stratagies
1. Bronchospasm
  1. Inhaled Beta Agonists
2. Pulmonary Edema from freshwater immersion
  1. Loop Diuretics
3. Airway protection from aspiration as indicated
  1. Intubation
  2. Nasogastric suction
4. Hypoxia
  1. CPAP
  2. Mechanical Ventilation indications
    1. pCO2, mental status, work of breathing
5. Unstable Patients require aggressive management
  1. Intubation and Mechanical Ventilation
  2. IV fluids and Pressors (Dopamine) for Hypotension
6. Metabolic Acidosis
  1. Maximize oxygenation and fluid Resuscitation
  2. Sodium Bicarbonate ONLY for severe acidosis (<7.10)
7. Hyperglycemia
  1. Pathophysiology
    1. Associated with Catecholamine release
    2. May worsen encephalopathy
  2. Management
    1. Insulin drip to lower Glucose <300 mg/dl
8. Mental Status Depression
  1. Background
    1. Global Brain Hypoxic-Anoxic Injury is associated with significant morbidity and mortality
      1. In non-Fatal Drowning, anoxic brain injury is the most common cause of death
    2. Core concepts to improving neurologic outcome
      1. Maintain adequate brain perfusion (manage Hypotension)
      2. Maintain euglycemia
  2. Induced Therapeutic Hypothermia
    1. Controversial in Drowning due to lack of evidence and underwhelming outcomes
    2. Not proven effective in pediatric Cardiac Arrest (except in case reports)
  3. Evaluation
    1. Neuro status usually improves with Resuscitation
    2. If Mental status depression/Seizure continues:
      1. Consider CT Head (r/o Head Injury)
      2. Consider Alcohol and Illicit Drug testing (see Unknown Ingestion)
  4. Management Seizures
    1. Supportive care
    2. Prolonged Seizure
      1. Diazepam or Ativan (0.1 mg/kg)
      2. See Status Epilepticus

Complications
Multisystem organ dysfunction from Hypoxia and Hypoxemia (in order of frequency)

Respiratory dysfunction due to aspiration (significant injury even for >1-3 ml/kg fluid aspirated)
1. Acute Respiratory Distress Syndrome (ARDS)
2. Pulmonary insufficiency
3. Aspiration Pneumonia, Lung Abscess, empyema
  1. Especially if water contaminated
  2. Infections vary by water type (e.g. Legionella in fresh water), but most are polymicrobial
4. Pneumothorax, Pneumomediastinum, Barotrauma from high Ventilatory pressure
Neurologic dysfunction
1. Cerebral Edema
2. Increased Intracranial Pressure
3. Seizures
4. Brain injury (e.g. watershed infarcts)
  1. Cognitive Impairment
  2. Persistent anoxic-ischemic encephalopathy
Cardiovascular dysfunction
1. Arrhythmias
2. Hypothermia related EKG Abnormalities (e.g. Osborn Wave or J Wave)
3. Takotsubo Cardiomyopathy
Other less frequent abnormalities
1. Sepsis
2. Hypothermia
3. Hyperglycemia (from Catecholamine release)
4. Hepatic Dysfunction
  1. Coagulopathy (associated with Hypothermia)
5. Hematologic Dysfunction
  1. Traumatic Myoglobinuria or Hemoglobinuria
6. Renal Dysfunction
  1. Renal Failure (Acute Tubular Necrosis)

Prognosis

Predictors of survival and good neurologic outcome
1. Pulse and detectable Blood Pressure on admit
2. Young age
3. Early rescue breaths by life guards or rescuers while patient still in water (often not feasible)
4. Hypothermia (Core temp <95F or 35C)
  1. See Hypothermia Management above
  2. Water Temperature must be 6 C (42.8 F) or colder to induce rapid body cooling for neuroprotection
  3. Diving reflex to very cold water is protective (breath holding, Bradycardia, redistribution)
  4. Protection depends on rapid onset Hypothermia
  5. Child submerged 66 min in ice cold water survived neurologically intact (case report)
  6. In at least one 2014 study, water Temperature did not impact survival (see Quan reference below)
5. Submersion time (modified by Hypothermia)
  1. Time 0-5 minutes: 90% survival without severe neurologic deficit
  2. Time 6-10 minutes: 44% survival without severe neurologic deficit
  3. Time 11-25 minutes: 12% survival without severe neurologic deficit
  4. Time >25 minutes: 0% survival without severe neurologic deficit
Predictors of poor prognosis
1. pH < 7.10
2. GCS < 5
3. Pupils fixed and dilated on admit
4. Persistent acidosis and coma 4 hours after Resuscitation
5. Time to basic life support >10 minutes
6. Cardiac Arrest at any age
7. Submersion for 6 minutes or longer (7.4% with good outcomes compared with 88% if <6 minutes)
  1. Water Temperature did not impact survival
  2. Quan (2014) Resuscitation 85(6):790-4 +PMID: 24607870 [PubMed]
8. Resuscitation >25-30 minutes (even in children with cold water drowing)
  1. Kieboom (2015) BMJ 350:h418 [PubMed]
Outcomes
1. Children requiring PICU admit for near Drowning
  1. 30% mortality
  2. 10-30% severe brain injury (e.g. persistent vegetative state, spastic Quadriplegia)
2. Overall
  1. 92% non-Fatal Drowning survivors recover completely

Prevention

Avoid swimming under influence of Alcohol, Illicit Drug
1. Alcohol is found in 30-70% of Fatal Drowning victims
2. Even small amounts of Alcohol increase risk, and risk increases in relationship to amount consumed
Never swim alone
Swim in areas with lifeguards
1. Rescues by lifeguards require medical attention in only 6% of cases and CPR in 0.5% of cases
Home swimming pool safety
1. Install drain covers, vacuum release systems and multiple drains to displace pressure
2. Install rescue equipment around pool (reaching pole, life buoys, working telephone)
3. Install fence around home swimming pool
  1. At least 5 feet high with vertical openings <4 inches, and <4 inch opening at ground level
  2. Fence completely encloses pool on 4 sides (not attached to house on one side)
  3. Self closing and lockable gate (latching mechanism at least 58 inches above ground)
  4. Fence should not be climbable (e.g. not chain link)
All family members should learn to swim
1. However, a child's swimming ability does not replace active adult supervision
Learn Cardiopulmonary Resuscitation (CPR)
Safe proof home for infants and toddlers
1. Never leave infants unsupervised in bath (do not substitute bath stands for direct supervision)
2. Avoid leaving standing water in buckets, containers
3. Do NOT leave water in home plastic wading pools
4. Drownings often occur despite at least one adult present, but with momentary lapses in supervision
Water sport participants
1. Practice standard boating safety
2. Avoid Alcohol while operating vehicles
3. Wear approved personal floatation devices (floatable, air-inflated aids are not a substitute)
Open water precautions
1. Rip currents (away from beach) should be countered by swimming parallel to current until cleared
2. Swift currents under rocks or trees can trap swimmers
References
1. Griffith (1994) Patient Instructions

Resources

CDC Unintentional Drowning
1. http://www.cdc.gov/HomeandRecreationalSafety/Water-Safety/waterinjuries-factsheet.html
Personal floatation devices
1. http://www.uscg.mil/hq/cg5/cg5214/pfdselection.asp

References

Chavez and Johnston (2022) Crit Dec Emerg Med 36(8): 21-9
Long (2018) Crit Dec Emerg Med 32(9): 17-24
Nordt, Spangler, Schmidt and Borghei in Herbert (2015) EM:Rap 15(7): 2-4
Layon (2009) Anesthesiology 110(6): 1390-401 [PubMed]
Mott (2016) Am Fam Physician 93(7): 576-82 [PubMed]
Szpilman (2012) N Engl J Med 366(22): 2012-2110 [PubMed]
Thanel (1998) Postgrad Med 103(6):141-54 [PubMed]