- Prevention is better than cure, we should all be vocal advocates for pool fences
- Respiratory support is the intervention most likely to be required
- Time to first breath is critical (hence those poolside CPR posters)
- Beware of respiratory deterioration
- Predicting prognosis is difficult but CPR for >30 mins is a bad sign in Australian water
- If you think the patient was hypothermic before they arrested, prolonged resuscitation is generally appropriate
- It makes no difference whether your patient drowned in salt or fresh water
- Antibiotics don’t help
What actually happens when someone drowns?
After a period of voluntary breath-holding, reflex inspiratory efforts cause aspiration and laryngospasm. As the laryngospasm eases the patient actively breathes the liquid medium. Pulmonary surfactant is washed out and the endothelium of the pulmonary capillaries is disrupted. Alveoli collapse, pulmonary hypertension develops with associated intrapulmonary shunting of blood. Hypoxaemia leads to multiple organ damage and eventually failure. CO2 is not eliminated and the patient becomes acidotic. Whether the victim drowned in salt or fresh water is basically irrelevant in terms of pathology and management.
What can I do to make the patient better?
Respiratory support is the key intervention. Drowning victims may require oxygen. Bronchodilators may also be helpful, though anyone who improves with these should still be watched very closely. Positive pressure may be useful if hypoxaemia is resistant to O2 supplementation though whether CPAP/BiPAP is superior to high-flow nasal cannulae is not known. If invasive ventilation is required then remember that these are injured lungs and follow ARDS protocols (7ml/kg tidal volumes with physiologic PEEP).
Fluid resuscitation may be required, especially if the patient got cold as this can induce a diuresis in itself. Seizures are not necessarily predictive of outcome but they can worsen the underlying ischaemic injury and should be treated aggressively.
What interventions might help?
Surfactant use has been reported in case studies and it makes physiologic sense that this would be helpful but it is expensive, not generally available in the ED and there is not yet any solid evidence to support its use. ECMO is an aggressive but exciting option in resuscitation of cardiac arrest victims in certain circumstances including drowning. It has been used in some impressive case reports including one described below but has very limited availability and its place in resuscitation is still evolving.
What interventions do not help?
Steroids and antibiotics have both been studied and found unhelpful. There are no paediatric RCTs of therapeutic hypothermia after cardiac arrest. The AHA (2006) recommended that hypothermia be considered in kids who remain comatose post-arrest, based on extrapolating adult data. That, however, was before 2013’s Targeted Temperature Management (TTM) trial showed that cooling to 33 degrees C post-arrest was no better than keeping temps below 36oC. I think the bottom line is we cannot be confident that therapeutic hypothermia is useful but it is certainly reasonable to avoid pyrexia (T>38oC).
Do drowning victims need C spine immobilization?
This is totally dependent on history – a toddler in the bath obviously doesn’t, but any mechanism that may have involved diving, a jetski or ocean waves is a different matter. The important thing is to think about it.
When can I send this patient home?
Historically children were admitted to hospital for 24 hrs following a drowning event based on a, thus far largely unsubstantiated, fear of “secondary drowning” or delayed respiratory deterioration secondary to surfactant disruption. I am generally comfortable discharging, into reliable parental care, patients who are asymptomatic with a normal exam and normal O2 sats at 4-6 hrs post-injury. There is little evidence on which to base practice but I have a low threshold for admitting patients overnight if there is any suggestion of respiratory compromise however minor or if they have had symptoms, which have required salbutamol for resolution. Continuous pulse oximetry seems reasonable though HDU level care is probably unnecessary if the child has a normal mental state and only mild-moderate respiratory distress.
There are peaks of incidence in the under 5s (presumably largely due to lapses in supervision) and in young men (often attributed to misadventure). Toddlers have been known to drown in buckets or toilets. If the circumstances are not clear it is worth considering underlying causes, which may have consequences for others even if the outcome is fatal, the classic example of which is long QT syndrome. It has been reported that up to 38% of bathtub drownings in the under 5s are inflicted. I don’t think that finding has ever been reproduced but child protection issues, whether they be physical abuse or neglect related, should always be a consideration.
What can we do to stop kids drowning?
This may sound obvious but adequate supervision of kids around water is essential. Swimming lessons should be encouraged early in life. Appropriate education regarding showering versus bathing and not swimming alone should be provided to all older kids with seizure disorders. Pool fence legislation has done more than any other intervention to reduce childhood drowning. Yes it’s a hassle to get them inspected, sure you can’t baby-proof the world, but childhood drownings are tragic and often preventable so be an advocate for pool fencing.
How can I tell when to stop resuscitation?
Assessing prognosis is often difficult. At one extreme kids with stable vital signs and normal mental status, predictably, have a rate of neurologically intact survival of basically 100%. Kids who require less than 10 mins of CPR, breathe spontaneously after CPR, and arrive at the ED with a pulse generally do well, as do those who score at least a P on the AVPU scale on ED arrival. Prognosis worsens with increasing submersion time, resuscitation time, time to effective resuscitation, water temperature, and core body temperature.
A number of studies have found no neurologically intact survivors after durations of resuscitation between 25-31 minutes in normothermic patients. However, a 2005 ILCOR statement concluded that good outcomes are possible after 30 mins of CPR with warm water submersion and 60 mins of CPR with ice-water submersion.
Are you really not dead until you are warm and dead?
Hypothermia is certainly protective and there are some amazing stories of kids who have been pulled from frozen lakes and come out of resuscitation efforts that can only be described as heroic, in a good neurological state. A 2 year old girl whose case was reported in 1988 holds the record for longest submersion with neurologically intact survival at 66 minutes! She had a core temp of 19oC on arrival in the ED and recovered after 2 hours of CPR with extra-corporeal warming. The key seems to be whether the child got cold and then arrested or arrested and then got cold. Hypothermia prior to arrest offers some neuroprotection and makes prolonged resuscitative efforts entirely appropriate. If you are an EMRAP subscriber they have an excellent section on this in their January 2014 episode.
Rose E and Denmark TK. (2011) An evidence-based approach to the evaluation and treatment of drowning and submersion injuries. Paediatric Emergency Medicine Practice. Vol 8 No 6.
Lavelle J et al. (1995). Ten year review of paediatric bathtub near-drownings: evaluation for child abuse and neglect. Ann emerg Med 25;344-48.
The International Liason Committee On Resuscitation (ILCOR). Consensus on science with treatment recommendations for paediatric and neonatal patients: paediatric basic and advanced life support. Pediatrics 2006;117;e955-977
Nielsen N et al. (2013). Targeted Temperature Management at 33C versus 36C after cardiac arrest. N Engl J Med 369:2197-2206.