Drowning is the process of experiencing respiratory impairment from submersion or immersion in a liquid (regardless of outcome).
Definitions related to drowning:
Submersion - the act of being completely covered by a liquid
Immersion - being partly covered by a liquid (in medical terms this usually includes the face)
- Previously, the term “near drowning” was used to indicate patients that survived for > 24 hours following a drowning event. Whilst this term is still commonly used, it has been replaced by the term “non-fatal drowning”
In Australia this is a big problem. It is the second most common cause of accidental death in children in Australia.
Boys : girls 5:1
Highest incidence in 0 - 4 years old
Most urban drownings occur in private swimming pools; around 20% occur in bathtubs
Alcohol is a big risk factor in teenagers
- Always consider the possibility of non-accidental injury in children
Patients panic, struggle, breath hold and eventually either aspirate or go into laryngospasm.
It was previously thought that patients may undergo “wet drowning” or “dry drowning” as follows:
“Wet Drowning” - due to aspiration of water into the lungs (85% of cases)
“Dry Drowning” - hypoxia due to laryngospasm (15% of cases)
However, more recent autopsy studies of drownings have shown at least some level of increased fluid in the lungs in over 98% of victims, suggesting that aspiration occurs in almost all cases.
Most deaths in hospital are due to hypoxic brain injury, rather than from pulmonary oedema or lung injury from the initial drowning incident.
Historically if available it is useful to know:
Length of submersion
Type of water, contamination and water temperature
Other associated trauma (e.g. fall, boating accident, diving in shallow water)
Other factors involved such as alcohol and drugs
Underlying conditions such as epilepsy
Prehospital care provided, including vital signs and GCS on arrival of EMS
- CXR (looking for pulmonary oedema)
- CT brain (if focal neurological signs or significant head trauma)
- Other as indicated by clinical picture, e.g. skeletal survey in suspected NAI
Treat as a trauma - primary survey, ABCDE approach and immediate resuscitation in systems.
The same principles apply whether wet or dry drowning, and for salt and fresh water submersions.
Call for help early - senior ED doctor
Airway - ensure airway is clear of fluid or debris e.g. sand, vomit; protection if necessary
Breathing - immediate respiratory support is important in the initial resuscitation (compression only CPR should not be used in drowning victims).
- High flow oxygen
Non-invasive ventilation (CPAP) has been shown to improve oxygenation (PEEP 10 cm water)
Endotracheal intubation if reduced LOC or hypoxia with supplemental oxygen and CPAP
Circulation - if arrested, usually initial rhythm is asystole or PEA - follow usual ALS pathway
- IV fluids often needed to correct hypovolaemia
Disability - institute neuroprotective measures to minimise further brain injury
- Avoid hypoxia, maintain normoglycaemia, prevent hyperthermia, treat seizures
- No evidence that steroids have a neuro-protective effect
Exposure - in cooler climates, drowning is often associated with hypothermia
- Rewarming measures may be required, especially if core temp is < 35°C
C spine immobilisation - protect the cervical spine if trauma is suspected
- Spinal injuries occur in < 0.5% of drowning victims, however be suspicious if history of trauma such as diving into shallow water or boating accident
Use of antibiotics - no evidence that prophylactic antibiotics should be given, unless liquid was contaminated (e.g. containing raw sewage)
If awake with no ABC problem can be safely discharged after a period of 6 hours of observation in the ED (to ensure hypoxia +/- pulmonary oedema don’t develop).
No single clinical score accurately predicts which patients will survive post a drowning event. Some studies show correlation between submersion time and survival – other factors include water temperature, time to CPR and time to first spontaneous respiratory effort.
The Orlowski scale is commonly used to predict outcomes post drowning - based upon the following features:
- Age < 3 yrs
- Estimated submersion > 5 minutes
- No attempted resuscitation in first 10 minutes after rescue
- Coma on arrival in ED
- Metabolic acidosis on arrival in ED with pH < 7.1
It is predicted that there is a 90% chance of good recovery if < 3 of these are present and a 5% chance of recovery if > 3 are present.
Further Reference and Resources
Resuscitation of drowning victim (Guideline 9.3.2) - Australian Resuscitation Council and NZ Resuscitation Council
Resuscitation of divers who have used compressed gas (Guideline 9.3.5) - Australian Resuscitation Council and NZ Resuscitation Council
- Szpilman D, Bierens JJ, Handley AJ, Orlowski JP. Drowning. N Engl J Med. 2012 May 31;366(22):2102-10