Drowning

Aka: Drowning, Near-drowning, Nonfatal Drowning, Fatal Drowning

1. Definition
   1. Drowning (WHO Definition)
      1. Respiratory Impairment from submersion or immersion in liquid
      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)
2. Epidemiology
   1. Deaths per year
      1. Worldwide: 140,000-300,000
      2. United States: 4,000 to 8,000
   2. Incidence peaks May to August in United States
   3. Males account for 80% of Drowning deaths
   4. 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
3. Causes
   1. Home pools (50% of Drowning cases in United States)
      1. Age under 5 years accounts for 90% of cases
   2. Bathtub
      1. Second most common site for preschool Drowning cases
      2. Majority ages 7 to 15 months old
   3. Occupations
      1. Fishing industry (especially Alaska)
   4. 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]
   5. Alcohol and Illicit Drugs
      1. Involved in over 50% adolescent Drowning cases
   6. Developmental or neurologic Impairment
   7. Epilepsy
   8. 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
   9. Physical Abuse
      1. Accounts for 8% of childhood Drowning cases
      2. References
         1. Gillenwater (1996) Arch Pediatr Adolesc Med 150:298 [PubMed]
4. Risk Factors
   1. Home pool childproofing lacking
   2. Unable to swim
   3. Adult supervision lacking
   4. No life jacket use
   5. Alcohol or drug use
   6. Risk taking behavior
   7. Cardiac events
   8. Seizure disorder
   9. Developmental Disorder
5. Mechanism
   1. Patient struggles to stay above water and hold breath as they submerge
      1. Ultimately a breath is taken with subsequent laryngospasm or aspiration
   2. Aspirated water disrupts alveolar-capillary membrane
      1. Results in Atelectasis, surfactant loss and Ventilation-Perfusion Mismatch (V-Q Mismatch)
      2. Causes severe hemorrhagic pulmonary edema and bronchospasm
      3. Asphyxia leads to Hypoxemia and Metabolic Acidosis
      4. Cardiac rhythm degenerates over minutes from Tachycardia to Bradycardia to PEA to Asystole
   3. Dry Drownings on autopsy (no lung water): 10-20%
   4. Small-moderate amount water aspirated (<22 ml/kg): 85%
   5. Freshwater and Saltwater Drownings are treated the same
      1. Both fresh and saltwater in alveoli cause surfactant dysfunction
6. Complications
   1. Adult Respiratory Distress Syndrome
   2. Persistent anoxic-ischemic encephalopathy
   3. Aspiration Pneumonia, Lung Abscess, empyema
      1. Especially if water contaminated
   4. Pneumothorax, Barotrauma from high Ventilatory pressure
   5. Traumatic Myoglobinuria or Hemoglobinuria
   6. Renal Failure (Acute Tubular Necrosis)
   7. Coagulopathy (associated with Hypothermia)
   8. Sepsis
   9. Hypothermia
   10. Hyperglycemia (from Catecholamine release)
   11. Seizures
7. Evaluation: First Responders
   1. Move patient immediately to land and position supine
      1. In-water Resuscitation (ventilations) only if rescuer is skilled in that technique
   2. Start bystander CPR without delay
      1. Outcomes are best with immediate initiation of high quality CPR
   3. Apply AED when available (and on a relatively dry surface)
   4. Remove wet clothing and apply dry towels, blankets and other methods of rewarming
8. Evaluation: No response to verbal or tactile stimuli (prehospital EMS)
   1. Ventilations are performed first instead of compressions (ABC instead of CAB)
   2. 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)
   3. Pulse absent
      1. Submersion >1 hour or signs of death (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%
   4. 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%
9. Evaluation: Responds to verbal or tactile stimuli (prehospital EMS)
   1. 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%
   2. 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
10. Imaging
    1. Chest XRay
       1. Initial XRay is typically normal (ARDS findings delayed)
11. Diagnostics
    1. Electrocardiogram (EKG)
12. Labs
    1. Arterial Blood Gas
    2. Complete Blood Count
    3. Comprehensive Metabolic Panel (rarely abnormal)
    4. Coagulation Studies (INR, PTT, rarely abnormal)
    5. Blood Alcohol Level (if indicated)
    6. Urine Drug Screen (if indicated)
    7. Pregnancy Test (if indicated)
13. Management: Initial
    1. 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
    2. Initial ACLS management
       1. ACLS protocol
       2. Respiratory management is paramount
          1. 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
          2. Non-Invasive Positive Pressure Ventilation for conscious patients
             1. Move to intubation if not improving in first 10-30 minutes
       3. 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)
       4. Observation for Vomiting and aspiration risk
          1. Occurs in 30-85% of Drowning victims who swallow large water volumes
       5. Intravenous Fluids
          1. Persistent Hypotension is associated with worse outcomes
       6. Hypothermia
          1. Cold water Drownings are protective of neurologic status
             1. Drowning victims are "not dead unless warm and dead"
             2. Cerebral oxygen (and ATP) consumption drops by 5% per every 1 C below 37C
             3. 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
       7. 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
    3. Medical facility management
       1. Continue ACLS protocol
       2. Reevaluate airway and consider intubation (see indications above)
       3. 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)
14. Management: Disposition
    1. 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 AND
       3. No symptoms AND
       4. No preexisting Neurologic or cardiopulmonary disease AND
       5. GCS 14 or 15
    2. Criteria for routine hospital ward observation for 24 hours
       1. Patients with minimal symptoms (mild cough) AND
       2. Normal Oxygen Saturation
    3. Criteria for ICU admission
       1. Above criteria not met
       2. Any signs of respiratory distress
    4. References
       1. Brennan (2018) Am J Emerg Med 36(9):1619-1623+PMID:29452918 [PubMed]
       2. Shenoi (2017) Acad Emerg Med 24(12): 1491-500 [PubMed]
15. Management: ICU
    1. Monitoring
       1. Continuous O2 Sats and frequent lung auscultation
       2. Urine Output
       3. Electrolytes and Glucose
       4. CXR
       5. ABG
    2. 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. 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)
          2. 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
          3. Management Seizures
             1. Supportive care
             2. Prolonged Seizure
                1. Diazepam or Ativan (0.1 mg/kg)
                2. Consider Dilantin loading
16. Complications: Multisystem organ dysfunction from Hypoxia and Hypoxemia (in order of frequency)
    1. Respiratory dysfunction due to aspiration (significant injury even for >1-3 ml/kg fluid aspirated)
       1. Acute Respiratory Distress Syndrome (ARDS)
       2. Pulmonary insufficiency
    2. Neurologic dysfunction
       1. Cerebral Edema
       2. Increased Intracranial Pressure
       3. Cognitive Impairment
    3. Cardiovascular dysfunction
       1. Arrhythmias
          1. Sinus Tachycardia
          2. Sinus Bradycardia
          3. Pulseless Electrical Activity (PEA)
          4. Asystole
       2. Hypothermia related EKG Abnormalities (e.g. Osborn Wave or J Wave)
    4. Other less frequent abnormalities
       1. Hepatic Dysfunction
       2. Hematologic Dysfunction
       3. Renal Dysfunction
17. Prognosis
    1. 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. Diving reflex to very cold water is protective
             1. Breath holding, Bradycardia, redistribution
          3. Protection depends on rapid onset Hypothermia
          4. Child submerged 66 min in ice cold water survived neurologically intact (case report)
          5. In at least one 2014 study, water Temperature did not impact survival (see Quan reference below)
       5. Submersion time
          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
    2. 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]
    3. 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
18. Prevention
    1. 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
    2. Never swim alone
    3. Swim in areas with lifeguards
       1. Rescues by lifeguards require medical attention in only 6% of cases and CPR in 0.5% of cases
    4. 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)
    5. All family members should learn to swim
    6. Learn Cardiopulmonary Resuscitation (CPR)
    7. 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
    8. Water sport participants
       1. Practice standard boating safety
       2. Avoid Alcohol while operating vehicles
       3. Wear personal floatation devices (floatable, air-inflated aids are not a substitute)
    9. 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
    10. References
        1. Griffith (1994) Patient Instructions
19. Resources
    1. CDC Unintentional Drowning
       1. http://www.cdc.gov/HomeandRecreationalSafety/Water-Safety/waterinjuries-factsheet.html
    2. Personal floatation devices
       1. http://www.uscg.mil/hq/cg5/cg5214/pfdselection.asp
20. References
    1. Long (2018) Crit Dec Emerg Med 32(9): 17-24
    2. Nordt, Spangler, Schmidt and Borghei in Herbert (2015) EM:Rap 15(7): 2-4
    3. Mott (2016) Am Fam Physician 93(7): 576-82 [PubMed]
    4. Szpilman (2012) N Engl J Med 366(22): 2012-2110 [PubMed]
    5. Thanel (1998) Postgrad Med 103(6):141-54 [PubMed]