emDOCs Podcast – Episode 70: Drowning

Today on the emDOCs cast, Brit Long, MD (@long_brit) interviews Sophia Gorgens, MD, on the evaluation and management of the drowning patient.

Episode 70: Drowning

Epidemiology:

• Drowning is one of the leading causes of accidental deaths across the world and leading cause in children less than 15 years.
  • Young adults are at risk due to suicide and drug ingestion; elderly adults may accidentally drown in bathtubs.
  • In the U.S., there are 11 deaths from drowning per day (over 4000 per year), with 22 non-fatal drowning incidents per day (over 8000 per year).

Pathophysiology:

• Drowning results from respiratory impairment after submersion in a liquid.
  • Aspiration of liquid causes a loss of surfactant, pulmonary edema, and hypoxia, which in turn can lead to cardiac arrest.
  • The diving reflex – bradycardia, apnea, peripheral constriction – is thought to be protective, but few experience this.
  • Irreversible neuronal cell injury can start as early as 4-6 minutes into hypoxemia.
  • No difference between evaluation or management of saltwater vs. freshwater drowning.
  • Dry drowning has been used to describe a person found dead in the water without evidence of water aspiration. Dry drowning is not an actual medical term and is problematic because it may result in misdiagnosis and mismanagement.

Prehospital care:

• After removing the patient from the water, rapid resuscitation is key to improved morbidity and mortality.
• If the patient is not breathing or does not have a pulse, immediately start CPR and rescue breaths. Use a BVM to provide positive pressure. Intubation may be needed.
• If they are breathing, administer oxygen through a non-rebreather, facemask, or nasal cannula.

Concomitant Trauma:

• 0.5 to 5% of drownings involve traumatic injuries (most commonly cervical spine injuries from diving).
• Unless the mechanism of drowning is suspicious or known to be traumatic, c-spine precautions and trauma activation upon arrival in the ED are likely not necessary.

ED Care:

• When drowning patients arrive in the ED, they can generally be divided into 2 categories: the well appearing patient and the critical patient.
• Well-appearing, not critically ill:
  • If vital signs and exam are normal, observe for 4-6 hours. If they remain stable and have no symptoms, then discharge is appropriate. If they develop symptoms, hypoxemia during this observation time, obtain labs and CXR.
  • If they are hypoxemic initially, after pulmonary findings, or decompensate during observation, obtain labs and CXR. Provide supplemental oxygen for those with hypoxemia and speak with medical ICU.
  • Discharge should be considered if there are no symptoms, the patient has no oxygen requirements, and labs and imaging (if obtained) are reassuring.
• Critical patients:
  • Focus on airway, breathing, circulation.
  • Due to a loss of surfactant and pulmonary edema, ventilation is a problem.
  • Start with supplemental oxygen. If they are in respiratory distress, start noninvasive positive pressure ventilation. If they fail this or are altered, intubate.
  • If intubated, use lung protective ventilation strategy: low TV and high PEEP. ECMO may be an option.
  • Antibiotics and steroids are not routinely recommended.
  • If hypothermic, aggressively rewarm the patient. The evidence behind hypothermia being protective for neurological recover in drowning patients is mostly case-report based.

Prognosis:

• Drowning-associated mortality ranges from 31-74%.
• Asystole, resuscitation > 30 minutes associated with poor prognosis.
• Asystole, especially, is associated with a poor prognosis.
• Generally, by 24 hours after the drowning event, a patient will have made either a full or near-full cardiopulmonary and neurologic recovery.

Prevention:

• Prevention is key. Educate patients/parents on safe water practices: swimming under supervision, implementing pool barriers for children, using life vests, and avoiding substance use.

Summary:

• Drowning results from respiratory impairment after submersion in a liquid.
• Saltwater and freshwater drowning should be treated the same.
• Focus on airway, breathing, circulation initially.
• All patients should be evaluated for trauma, but traumatic injuries are overall rare.
• If well appearing, normal vital signs including oxygen saturation, observe 4-6 hours.
• If critically ill, resuscitate, provide supplemental oxygen, and intubate if necessary. Use ARDSnet ventilator settings.
• Antibiotics and glucocorticoids are not routinely recommended in the ED.

Further Reading:

• http://www.emdocs.net/drowning-and-submersion-injuries/
• Tintinalli’s Emergency Medicine 9^th Edition, Chapter 215: Drowning. Pp 1374-1376.
• Thom O, Roberts K, Devine S, Leggat PA, Franklin RC. Treatment of the lung injury of drowning: a systematic review. Crit Care. 2021;25(1):253
• Szpilman D, Sempsrott J, Webber J, et al. ‘Dry Drowning’ and other myths. Cleve Clin J Med. 2018; 85(7): 529-535.
• Kriz D, Piantino J, Fields D, Williams C. Pediatric Hypothermic Submersion Injury and Protective Factors Associated with Optimal Outcome: A Case Report and Literature Review. Children (Basel). 2017;5(1):4.
• Reizine F, Delbove A, Dos Santos A, et al. Clinical spectrum and risk factors for mortality among seawater and freshwater critically ill drowning patients: a French multicenter study. Crit Care. 2021;25(1):372.
• Armstrong EJ, Erskine KL. Investigation of Drowning Deaths: A Practical Review. Acad Forensic Pathol. 2018;8(1):8-43.
• Hunn ES, Helmer SD, Reyes J, Haan JM. Patterns of Injuries in Drowning Patients – Do These Patients Need a Trauma Team?. Kans J Med. 2020;13:165-178.
• Cerland L, Mégarbane B, Kallel Het al. Incidence and Consequences of Near-Drowning-Related Pneumonia-A Descriptive Series from Martinique, French West Indies. Int J Environ Res Public Health. 2017;14(11):1402.
• Robert A, Danin PÉ, Quintard H, et al. Seawater drowning-associated pneumonia: a 10-year descriptive cohort in intensive care unit. Ann Intensive Care. 2017;7(1):45.