Updated 19/11/23 (awaiting further input from Keith Birch)

DROWNING

Drowning is respiratory impairment (suffocation) caused by submersion or immersion in a fluid, usually water.  This definition does not imply fatality, that the person becomes submerged or that any fluid will have necessarily entered the lungs. Drowning is the 3rd leading cause of unintentional injury death worldwide with children under the age of 12 more prone to drowning than any other group.

Near drowning is surviving a drowning event where the individual becomes unconsciousness or inhales water.  This can lead to serious secondary complications, including death at a later date.

Terminology:

• Immersion is when at least the face and airway is covered in water e.g. someone placing their face in a sink or a casualty in water face down, or face up with life jacket.

• Submersion is when the entire body including the airway is under water.

After submersion the victim holds their breath, the vocal cords close to protect the lungs (larygospasm) and the victim, swallows large amounts of water.  With no breathing taking place, blood oxygen levels fall & carbon dioxide levels rise, which causes the victim to loose consciousness.   Once consciousness has been lost the vocal cords relax and water flows into the lungs.  The heart rate slows and eventually, a cardiac arrest occurs as a result of hypoxia (not because of a primary cardiac problem). For more details on drowning see the section in Casualty Care in Mountain Rescue.

Although you may have heard of the terms drowning, near drowning and secondary drowning, for our purposes they should all be considered the  same as the initial management is identical.

This is because the current definitions relate to the length of survival and/or cause of death:

• Drowning is death within 24 hours from suffocation by submersion.

• Near drowning is survival for more than 24 hours (even if temporary) from suffocation by submersion.

• Secondary drowning is a nonspecific term for death after 24 hours from complications of submersion.
   

 Recognising Drowning

Drowning doesn't look like drowning as seen on TV, in movies or the image on the right where people wave, splash and shout for help.  People who still have the ability to keep afloat, signal for help and take actions are in aquatic distress and are not yet drowning.  Though this doesn't mean they aren't in trouble, in need of assistance to prevent them drowning.

Drowning itself although often preceded by distress is quick and silent. Because they cannot obtain enough air a drowning person is unable to shout, call for help or seek attention.  A set of autonomic reactions known as the instinctive drowning response which can appear to be normal calm behaviour to the untrained eye take effect in the final 20 – 60 seconds before the person sinks underwater.

Lifeguards and other people trained for water rescue learn to recognise drowning people by watching for these instinctive movements. For more information on how to recognise drowning see the description in the additional note section below.

Treatment - Unresponsive

The safety of the rescuer is the priority.  Cold water will affect rescuers as well.  Always be properly equipped before entering the water.

As with CPR there is a recongnised chain of survival for drowning.

Managing a casualty in water is probably impossible.  Move them to the shore as quickly as possible, attempting to keep them horizontal if practicable.

In cases of drowning the duration of hypoxia is the most critical factor in determining the casualty's outcome.  Restoring ventilation, oxygenation and perfusion as quickly as possible is the priority.

It is important to remember that in some circumstances it is still possible to revive an individual who has been underwater for a long time. The chances for resuscitation in this case is even better if the individual is young and/or was in very cold water.

Rapidly assess ABCD. It should be the quickest of primary surveys, to get to resuscitation started as quickly as possible, immediate resuscitation is essential for survival.

The first and most important treatment for drowning is to promptly give five initial rescue breaths by mouth-mouth, mouth-nose, or i-gel with supplementary oxygen if possible in order to start relieving the hypoxia.  Rescue breaths can be given whilst the victim is still in shallow water and can even be given whilst towing the victim if there will be a delay in reaching land. Follow the initial 5 rescue breaths with standard CPR at 30:2.  See cardiac arrest and CPR for more details.

Once on land or in a watercraft attach the AED and follow the instructions.  

Call for the Autopulse immediately to aid with compressions. As demonstrated during a drowning incident at the end of 2013, the Autopulse can be used to help lift the casualty from a watercraft onto land while compressions are still ongoing.

If there is no immediate resumption of breathing use an i-gel and bag-valve to assist breathing with supplemental high flow oxygen if possible.

Beware - vomiting is likely and regurgitated stomach contents can prevent adequate ventilation. Monitor the airway closely.  Be prepared to clear the airway, this may require turning the casualty onto their side.

If CPR is started for do not stop until the casualty has been re-warmed.  

If adequate spontaneous breathing returns administer high flow oxygen via a non rebreathing mask.

Remember - The casualty may have other injuries.  Concomitant cervical spine injury is rare, occurring in just 0.5% of reported cases (although the likelihood could be slightly higher in our potentially unusual circumstances).  Unless their history is especially suggestive of possible c-spine injury, immobilisation is not indicated and cervical collars could impair resuscitation efforts.

Treatment - Responsive

Move them to the shore as quickly as possible, try to keep them horizontal and handle them carefully.

Offer reassurance, drowning is a traumatic experience.

Administer high flow oxygen at 15ltrs per minute via a non rebreathing mask.

Be prepared to deal with vomiting, they may need to be turned onto their side to clear the airway.

Keep the casualty warm, hypothermia can occur rapidly in cold water.

Monitor them closely.

Consider the need for IV fluids.  A person who has been in the water for some time could be dehydrated.

Evacuate to hospital as quickly as possible, secondary complications can occur.

Hypothermia And Drowning

Water has the second highest specific heat capacity of any chemical compound (this means it takes lots of energy to raise the temperature) and a far higher thermal conductivity than air (0.6 vs 0.025 W/(m·K), which in simple terms means water can both absorb more heat from you than air and do it far faster.  As a result hypothermia can take effect very rapidly in cool or cold water and in our particular circumstances will often occur along side drowning.

As with other causes of hypothermia there is an associated decrease in metabolic requirement which can provide some neurological protection from hypoxia if the hypothermia occurs first, increasing the length of time over which resuscitation can be successful.

If submersion occurs in icy water (below 5°C), hypothermia may develop sufficiently rapidly to provide neurological protection, especially in children. There are a significant number of reported cases where resuscitation has been successful even after prolonged periods.

Life jackets prevent submersion and allow time for hypothermia to develop even in warmer water.  As the heart rate and respiratory effort decrease it becomes increasingly difficult to detect signs of life, if not impossible to detect in severe cases.  Unless there are other injuries incompatible with life or the chest or the abdomen has become incompressible, casualties with hypothermia should be treat as alive or potentially viable, but without palpable signs of life.

Remember as with other causes of severe hypothermia:

• Do not defibrillate more than 3 times.

• Do not use adrenaline.

• Handle carefully and try to keep horizontal.

• Use heat packs (do not place directly on the skin)

• Ensure the autopulse is available.

• Only remove wet clothing if absolutely necessary

See Hypothermia for more details.

Discontinuing Resuscitation

It is very difficult to decide when to discontinue resuscitation.  In rare circumstances, usually involving children submerged in ice cold water, neurologically intact survival has been reported after submersion in excess of 60 minutes.

No single factor can accurately indicate the likelihood of survival with 100% certainty.  The current advice is to continue resuscitation unless there is clear evidence that attempts will prove futile.  Factors which indicate resuscitation attempts will be futile are:

• Massive trauma.

• Incompressible chest

• Rigor mortis, putrefaction, etc.

• Timely evacuation to hospital is not possible.

If no other injuries are present, water temperature & duration of submersion/immersion are the most important factors influencing the decision. Dr Tipton an internationally recognised authority in the area of cold water survival has given the following general advice to SAR teams when considering resuscitation.

Survival becomes extremely unlikely if:

• If the water temperature is greater than 6°C and the casualty has been submerged for more than 30 minutes. or

• If the water temperature is below 6°C and the casualty has been submerged for greater than 90 minutes.

Always refer to the UKSAR Resuscitation Decision Tree Protocol (in Appendices of Casualty Care in MR book)

Drowning doesn't look like drowning.

“It Doesn’t Look Like They’re Drowning” How To Recognize the Instinctive Drowning Response By Aviation Survival Technician First Class Mario Vittone and Francesco A. Pia, Ph.D.

The characteristics of the instinctive drowning response are:
1. Except in rare circumstances, drowning people are physiologically unable to call out for help. The respiratory system was designed for breathing. Speech is the secondary, or overlaid, function. Breathing must be fulfiled, before speech occurs.

2. Drowning people’s mouths alternately sink below and reappear above the surface of the water. The mouths of drowning people are not above the surface of the water long enough for them to exhale, inhale, and call out for help. When the drowning people’s mouths are above the surface, they exhale and inhale quickly as their mouths start to sink below the surface of the water.

3. Drowning people cannot wave for help. Nature instinctively forces them to extend their arms laterally and press down on the water’s surface. Pressing down on the surface of the water, permits drowning people to leverage their bodies so they can lift their mouths out of the water to breathe.

4. Throughout the Instinctive Drowning Response, drowning people cannot voluntarily control their arm movements. Physiologically, drowning people who are struggling on the surface of the water cannot stop drowning and perform voluntary movements such as waving for help, moving toward a rescuer, or reaching out for a piece of rescue equipment.

5. From beginning to end of the Instinctive Drowning Response people’s bodies remain upright in the water, with no evidence of a supporting kick. Unless rescued by a trained lifeguard, these drowning people can only struggle on the surface of the water from 20 to 60 seconds before submersion occurs.