para>Proper water safety techniques are critical in avoiding morbidity and mortality from drowning.
ETIOLOGY AND PATHOPHYSIOLOGY
Hypoxemia via aspiration and/or reflex laryngospasm causing cerebral hypoxia and multisystem organ involvement
- 10 " 20% of victims drown without aspiration; likely due to prolonged laryngospasm, previously termed "dry lungs. "
- Bathtub and bucket drowning in children <1 year of age
- Swimming pool drowning in children and young adults
- Motor vehicle accidents (e.g., automobile submerged in water)
- Head trauma while swimming or diving
- Suicide
- Pulmonary: morbidity primarily as a result of hypoxia. Aspiration also causes dilution of surfactant with decreased gas transfer across alveoli, atelectasis, development of intrapulmonary right-to-left shunting; acute respiratory distress syndrome (ARDS); obstruction due to laryngospasm and bronchospasm
- Cardiac: hypoxic-ischemic injury and arrhythmia (primary or secondary)
- Renal: acute tubular necrosis from hypoxemia, shock, hemoglobinuria, myoglobinuria
- Neurologic: hypoxic-ischemic brain injury with damage especially to the hippocampus, insular cortex, and basal ganglia; cerebral edema
- Coagulation: hemolysis and coagulopathy
RISK FACTORS
- Alcohol ingestion
- Use of illicit drugs
- Seizure disorder
- Inability to swim
- Hyperventilation prior to underwater swimming
- Risk-taking behavior
- Inadequate physical barriers surrounding pools
- Boating mishaps and trauma during water sports, particularly when not wearing a life jacket
- Scuba diving
- Inadequate adult supervision of children
- Concomitant stroke or myocardial infarction (MI)
- Hypothermia
- Cardiac arrhythmias: familial long QT and polymorphic ventricular tachycardia (VT)
- Residence within sunbelt states
- African Americans
- Low socioeconomic status
- Lack of instruction regarding swimming and supervision
GENERAL PREVENTION
- Periodic education/reinforcement of supervision with an emphasis on drowning prevention for caretakers of young children
- Consistent practice of proper adult supervision of children
- Knowledge of water safety guidelines
- Mandatory physical barriers surrounding pools
- Pool alarms
- Fences higher than 54 inches (137 cm) for home pools
- Avoidance of alcohol or recreational drugs around water
- Swimming instruction at an early age
- Cardiopulmonary resuscitation (CPR) instruction for pool owners and parents
- Boating safety knowledge
- Personal flotation device (e.g., preserver, if necessary)
Pediatric Considerations
Children should never be left alone near water. Young children can drown in very small amounts of water, such as in bathtubs, buckets, and toilets.
COMMONLY ASSOCIATED CONDITIONS
- Trauma
- Seizure disorder
- Alcohol or illicit drug use
- Hypothermia
- Concomitant stroke or MI
- Cardiac arrhythmias: familial long QT and familial polymorphic VT
- Hyperventilation
DIAGNOSIS
HISTORY
- Victim found in or near water
- Duration of submersion
- Loss of consciousness
- Period of apnea
- Artificial ventilation/CPR performed
- History of associated trauma
- Approximate water temperature
- Recent use of alcohol or drugs
- Known seizure disorder
- Known cardiac disease, including arrhythmia or prolonged QT
- Preceding syncope or history of medical condition predisposing to syncope
PHYSICAL EXAM
- Airway status and degree of respiratory effort and/or distress
- Pulse: absent, weak, or normal
- Vital signs, including pulse oximetry
- Glasgow Coma Scale (GCS)
- Wheezing
- Evidence of trauma
DIFFERENTIAL DIAGNOSIS
Syncopal event, head trauma, arrhythmia, seizure, MI, stroke, alcohol or other substance overdose, nonaccidental trauma
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
May be unnecessary if initial GCS and pulse oximetry are normal and remain that way for 6 to 8 hours.
- CBC with differential
- Arterial blood gases (ABGs): hypoxia, hypercarbia, acidosis
- Electrolytes: hypokalemia, hyponatremia, hypernatremia
- Blood glucose: May be low if the cause of near drowning; increased levels may impair neurologic recovery after ischemic brain injury.
- BUN, creatinine: acute tubular necrosis
- EKG, cardiac monitoring and serial troponin: MI
- Creatine kinase (CK) and urine myoglobin: rhabdomyolysis
- Coagulation studies: coagulopathy
- Urinalysis/urine drug screen
- Blood alcohol level
- A chest x-ray (CXR) may be unnecessary for patients with all of the following:
- Normal initial GCS and pulse oximetry
- No evidence of respiratory distress
- No change after 6 to 8 hours of observation
- For others, a CXR may show evidence of aspiration, atelectasis, pneumothorax, or ARDS.
- Head CT and/or C-spine imaging as needed for associated trauma.
Follow-Up Tests & Special Considerations
- Patients with an initial GCS of 15 and pulse oximetry >95% should be observed for 6 to 8 hours in the emergency department (ED).
- CXR findings may be minimal or absent on early imaging.
Diagnostic Procedures/Other
- Continuous cardiac monitoring
- Continuous pulse oximetry
- Continuous core temperature monitoring if hypothermic
- ECG
- Central venous pressure (CVP) monitoring for critically ill patients with hypotension refractory to IV fluids
- Electroencephalogram (EEG) if suspect seizure as cause
TREATMENT
Early resuscitation and reversal of hypoxemia optimizes outcome.
GENERAL MEASURES
- Prehospital
- Never approach a struggling victim alone.
- Initially evaluate as per Basic Life Support (BLS) and Advanced Cardiovascular Life Support (ACLS) (3).
- Rescue breathing may be helpful while the victim is in the water and not able to be immediately removed from the water, but chest compressions in the water may not be effective and may even harm the rescuer and the victim (3)[C].
- Remove the victim from the water and begin effective resuscitation as quickly as possible (4).
- Early CPR that emphasizes effective chest compressions and rapid defibrillation as indicated.
- Start CPR if pulse is not definitely felt within 10 seconds, even in the hypothermic victim whose heart rate may be severely bradycardic (3)[C].
- Routine cervical collar use and spinal precautions are not needed unless a high suspicion for trauma exists (5)[C].
- Supplemental oxygen and early intubation, as needed (5)[A].
- If patient is breathing on his or her own and does not need spinal precautions, consider placing in the right lateral decubitus position to prevent aspiration of vomit or gastric contents (4).
- ED
- Oxygen, as needed, to maintain saturation >94%.
- Continuous positive airway pressure (PAP), BiPAP, or intubation if supplemental O2 alone is unsuccessful
- If intubation is indicated, employ lung-protective vent settings (lower end-inspiratory airway pressures, lower tidal volumes of 6 mL/kg, higher positive end-expiratory pressures of 6 to 12 cm H20) to avoid lung barotrauma (6)[A].
- Indications for intubation
- Neurologic deterioration
- Inability to protect the airway
- Inability to maintain oxygen saturation >90% or PaO2 >60 mm Hg on high-flow supplemental oxygen
- PaCO2 >50 mm Hg
- Remove wet clothing and initiate rewarming.
- Core temperature reading for possible hypothermia
- Rewarming with minimally invasive core rewarming such as warm IV fluids, warm/humidified oxygen, and external rewarming
- Active core rewarming reserved for refractory cases and only when extracorporeal blood warming is unavailable, depending on physician comfort level, due to major complications that can develop including core temperature after drop, rewarming acidosis, and rewarming shock.
MEDICATION
First Line
- High flow oxygen, as needed (4)[A]
- For bronchospasm: aerosolized bronchodilator (4)[C]: albuterol (Proventil, Ventolin), 3 mL of 0.083% solution or 0.5 mL of 0.5% solution diluted in 3 mL of saline
- Pressors, as needed, for hypotension refractory to IV fluid resuscitation
- Prophylactic antibiotics and steroids are not helpful (5)[B].
Second Line
For pneumonia: antibiotics based on sputum or endotracheal lavage culture (5)[A]
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
- All symptomatic patients
- Patients with abnormalities in vital signs, mental status, oxygenation, CXR, or laboratory analysis
IV Fluids
To maintain adequate intravascular volume (4)[C]
Nursing
- Continuous cardiac monitoring
- Continuous pulse oximetry monitoring
- Frequent monitoring of vital signs and clinical reassessment
- Careful monitoring of neurologic status
Discharge Criteria
Patients can be discharged from the ED after 6 to 8 hours of observation if the following criteria are met:
- GCS = 15
- Normal CXR, if indicated
- Lack of clinical evidence of respiratory difficulty
- Normal lung exam
- Normal vital signs
- Oxygen saturation ≥95% on room air (5)
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Appropriate follow up with primary care provider, orthopedic, neurologic, cardiac, pulmonary, and additional specialists as indicated
Patient Monitoring
- Continuous cardiac monitoring
- Continuous pulse oximetry monitoring
- Frequent monitoring of vital signs and clinical reassessment
- Careful monitoring of neurologic status
- ABG monitoring, as indicated (5)
- A pulmonary artery catheter may be needed for hemodynamic monitoring in unstable patients (4)[C].
- Intracranial pressure monitoring in selected patients (4)[C]
- Serum electrolyte determinations (5)
DIET
NPO until mental status normalizes
PATIENT EDUCATION
Re-emphasize preventive measures on discharge from hospital. Educate parents regarding supervision and preventive practices.
PROGNOSIS
- 75% of drowning victims survive; 6% of these with residual neurologic deficits
- Patients with an initial GCS ≥13 and an oxygen saturation ≥95% have a low risk of complications and an excellent chance for a full recovery.
- Patients who are comatose or receiving CPR at the time of presentation, as well as those who have dilated and fixed pupils and no spontaneous respiratory activity have a more guarded and often poor prognosis, often secondary to neurologic sequelae.
- Neurogenic pulmonary edema may occur within 48 hours of initial presentation.
COMPLICATIONS
- Early
- Bronchospasm
- Vomiting/aspiration
- Hypoglycemia
- Hypothermia
- Seizure
- Hypovolemia
- Electrolyte abnormalities
- Arrhythmia from hypoxia or hypothermia (rarely from electrolyte imbalance)
- Hypotension
- Late
- ARDS
- Anoxic encephalopathy
- Pneumonia
- Lung abscess/empyema
- Renal failure
- Coagulopathy
- Sepsis
- Barotrauma
- Seizure
REFERENCES
11 Centers for Disease Control and Prevention. Fatal injury reports. http://www.cdc.gov/injury/wisqars/fatal_injury_reports.html22 Centers for Disease Control and Prevention. Unintentional drowning: Get the facts. www.cdc.gov/HomeandRecreationalSafety/Water-Safety/waterinjuries-factsheet.html/33 Berg R, Hemphill R, Abella BS, et al. Part 5: adult basic life support: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2010;122(18)(Suppl 3): S685 " S705.44 Orlowski JP, Szpilman D. Drowning. Rescue, resuscitation, and reanimation. Pediatr Clin North Am. 2001;48(3):627 " 646.55 Salomez F, Vincent JL. Drowning: a review of epidemiology, pathophysiology, treatment and prevention. Resuscitation. 2004;63(3):261 " 268.66 Sutherasan Y, Vargas M, Pelosi P. Protective mechanical ventilation in the non-injured lung: review and meta-analysis. Crit Care. 2014;18(2):211.
CODES
ICD10
- T75.1XXA Unsp effects of drowning and nonfatal submersion, init
- T75.1XXD Unsp effects of drowning and nonfatal submersion, subs
- T75.1XXS Unsp effects of drowning and nonfatal submersion, sequel
ICD9
994.1 Drowning and nonfatal submersion
SNOMED
87970004 Nonfatal submersion (disorder)
CLINICAL PEARLS
- The single most important treatment for near-drowning victims is prompt reversal of the hypoxic state. This should form the cornerstone for all other treatment modalities. Without oxygenation, other treatment is futile.
- Family physicians and pediatricians should review water safety tips and guidelines with parents and children at yearly visits. Encourage pool owners and parents with young children to become CPR certified. Prevention of drowning can save many lives each year.
- Despite successful resuscitation, patients are at risk for ARDS due to delayed pulmonary edema that may start hours after their submersion incident. For this reason, careful monitoring of every resuscitated patient is essential.
- Patients requiring intubation should be treated with lung-protective vent settings to prevent barotrauma.
- Patients with an initial GCS ≥13 and an oxygen saturation ≥95% have a low risk of complications and an excellent chance for a full recovery.