Significant confusion in the literature with many different terms being used (Drowning, near-drowning, wet drowning, dry drowning, secondary drowning, etc)
Utstein consensus definition (Circulation, 2002): Process resulting in primary respiratory impairment from submersion/immersion in a liquid medium.
Hence, medicine has abandoned terms such as near drowning, secondary drowning, wet drowning, etc.
Low/middle income countries account for 90% of fatalities
Drowning is the leading cause of accidental death in children <5 years in locations where pools/beaches more accessible
Males, african americans, children 1-5, southern states, low socioeconomic status all associated with higher rates of drowning
In the US, approximately 4000 deaths/yr (~400,000 deaths/yr worldwide)
Overall drowning rates are decreasing over time
WHO Data re: US Drowning Related Mortality by Location (2017)
Location of drowning varies by age: Toddlers (bathtub, pool), Adolescents (natural bodies of water, risk taking behavior)
Prevention remains key (pool gates combined with adequate adult supervision. Estimates that up to 86% of drowning deaths for children <18yrs might be preventable using these measures.
Panic, abnormal breathing, breath holding, air hunger, struggle to stay above water
Hyopthermia, shivering, increased oxygen consumption
Reflex inspiratory effort +/- laryngospasm
Hypoxemia leading to hypoxic ischemic injury and eventual multiple organ dysfunction syndrome
Surfactant washout with impaired pulmonary compliance
VQ mismatch and intrapulmonary shunting
Hypotension (secondary to cold diuresis as blood moves to core, body senses increased volume status and decreases ADH production)- can also develop afterdrop (drop in blood pressure due to warming of extremities with subsequent reversal of peripheral vasoconstriction as well as drop in core body temperature)
Below 30C, shivering stops and heart rate and BP fall.
Salt water vs. Fresh water: Not thought to be important. Initially thought that salt water would lead to pulmonary edema via osmotic effect and conversely, fresh water would lead to volume overload/hemodilution. However, >11 cc/kg aspiration is needed for blood volume changes to occur and >22 cc/kg for electrolyte changes to occur. Usual aspiration in drowning is only 3-4 cc/kg.
Hypothermia: Initially thought to be potentially neuroprotective. However, hypothermia is usually a sign of prolonged submersion and multiple retrospective analyses have failed to demonstrate a protective effect of hypothermia. This may be different in very profound hypothermia
Remove from water
CPR if no response to 2 rescue breaths (hypothermic patient may have sinus bradycardia and barely palpable pulses so AHA recc is for 1 minute pulse check for these patients)
No evidence to support use of Heimlich manuever
Despite common concern for C-spine injury, extremely rare (0.5%) and when it does occur, is associated with obvious signs of injury and a concerning mechanism (i.e. dive into shallow water, MVC)
Intubation/mechanical ventilation if impaired neurological status and/or respiratory failuure/impending respiratory failure
Steroids: No evidence for their use
Surfactant: While biologically plausible, no evidence for efficacy
Prophylactic antibiotics: Not recommended unless grossly contaminated water
Seizure prophylaxis: If using, consider keppra/fosphenytoin to avoid sedative effects
Neuromuscular blockade: If needed for respiratory failure but generally try to avoid to allow for neurological examination
Mechanical ventilation strategies: Similar to standard ALI/ARDS management including targeting Vt ~ 6cc/kg, plateau pressures <30 cmH20. One caveat may be in the setting of presumed anoxic brain injury/cerebral edema- may not want to tolerate permissive hypercapnea in this setting due to risk of raising intracranial pressure
ECLS: No definitive evidence although has been used many times to support patients with refractory cardiopulmonary failure due to drowning. Overall 51% survival based on ESLO registry review of 246 patients.
ICP management: Avoid hypoxemia, hyper/hypo ventilation, hyperthermia, hyper/hypoglycemia, seizures. HOB 30 degrees, sedation, neck midline, C-collar not too tight, +/- Hyepertonic saline and mannitol.
Temperature management: Rewarm to 32-36 (THAPCA did not reveal differences between therapeutic hypothermia and normothermia). Rate of no more than approximately 1C/hr. Remove wet clothing. Can use passive external (blankets), active external (warm blankets/air), or active internal (Warm O2, warm fluids, pleural/peritoneal lavage, warm ECLS). Beware of afterdrop (cool peripheral vasoconstricted blood vasodilates with external warming of extremities, leading to hypotension and drop in core body temperature)
Concern for "Dry Drowning"
Confusion in lay literature/social media re: "Dry Drowning" (i.e. children having a small choking event in the pool and then dying days later). However, based on the literature, all patients who will exhibit symptoms have done so within 7 hours (Noonan L, Pediatrics 1996). Based on this observation, if the patient is asymptomatic 8 hours after the initial concerning event, they can be safely discharged home. Those that are symptomatic or within the 8 hour window should be admitted/observed, respectively.
Concern in lay press and social media re: "Dry Drowning." USA Today 2017
Risk factors for poor outcomes include:
Duration of submersion >5 minutes (most critical factor)
Time to effective basic life support >10 minutes
Resuscitation duration >25 minutes
Initial GCS <5
Persistent apnea and CPR requirement in ED
Initial pH <7.1
Lack of purposeful movements at 24 hours
Predictors of good outcome in drowning. (Quan L et al, Resuscitation 2014)