Electrocution in Children

Electrocution is surprisingly common, although rates of lightening strike are decreasing. Given that they should be well aware of the dangers of electricity, I was surprised that electricians and people who work with electricity are most likely to be affected. Electrocutions could affect people in hospital as well as out of hospital, and as the old adage goes, prevention is better than cure. It's not just high voltage electrocutions that cause problems, as a 33 year old with a domestic electrocution found.

If you look hard enough, you can find plenty of information online about electrocution. The AHA has a very thorough article online and EnlightenMe and LITFL have cases on the injuries associated with electrocution.
I know it's not FOAM, but the eLfH e-learning site has a fantastic e-learning module about electrical burns. It tells you a lot about those things that you always wondered about, but weren't quite sure about, and I'd really recommend completing it if you can.

So, lets get started.

Electrocution: death as a result of exposure to electric current

Electrical injury: Tissue damage as a result of exposure to electrical current

Electrical shock: The violent response to electric current exposure often characterised by involuntary muscle contraction.

1000 people per year are estimated to die from exposure to electricity each year. In 2005, there were 11 work related electrocutions and 119 serious injuries in the workplace. Electrical injuries follow a bimodal age distribution pattern - children younger than six, and in early adulthood.


The ability of an electrical current to cause morbidity and mortality is dependent on six different factors:
- Magnitude of the current
- Voltage of the electrical source
- Resistance of tissue types involved - (bone has the most resistance)
- Duration of exposure
- Type of current
- Current pathway

There are two main types of electricity that might cause us injury - low tension and high tension.
 
Low Tension

• <300 Volts 
• at 50hz  
• Alternating current  (AC)
• Domestic (110V in the US and Canada; 220V in Europe, Australia and Asia).
• Can cause VF
• Theoretical risk of late VF if shock travels through the thorax
  May cause tetanic skeletal muscle contractions - stopping people from letting go from the electricity source. Because AC current is repetitive it also increases the likelihood of current flow through the heart during the relative refractory period of the cardiac cycle which can precipitate ventricular fibrillation.
• Intraoral burns are common in young children (toddlers who explore electrical cables by placing them in their mouth). Conduction may be aided by electrolyte rich saliva. Delayed haemorrhage is a recognised feature. 
  Prevention is always important, and ROSPA have lots of advice (and lots of leaflets) about how to make your home safer.

High Tension

• >1000 Volts
• Lightening strikes and overhead power cables.
• Direct current
• May cause asystole, complete heart block and QT prolongation. 
• Keraunoparalysis - transient limb weakness, rarely lasting more than a few hours. Upper limbs > lower limbs. 
• Lightening strikes - mortality of 30%
• extensive autonomic stimulation - hypertension, tachycardia and nonspecific electrocardiographic changes
• brain haemorrhages, oedema and nerve injury.
• Lichtenberg’s flowers 
• Transient, fernlike erythematous floral pattern that develops on the skin
• Fades in 24 - 36 hours 

This type of electricity simultaneously depolarises the entire myocardium. This normally stops the heart completely, but sometimes the heart sorts itself out again and starts working normally again (it has intrinsic cardiac automaticity). This type of electricity also causes thoracic muscle spasm making it very difficult to breathe. Secondary hypoxic cardiac arreast is likely! Victims are most likely to die if they experience immediate respiratory or cardiac arrest and no treatment is provided - if treatment is provided at scene, results are often good. 
DC exposure is single, and often throws the victim away. A direct strike is uncommon, and often splashes sideways from an object or a victim may be holding on to a struck object.

Treatment

• Early basic life support and defibrillation if needed
• Airway:
• Secure the airway early (airway burns likely)
• C-Spine Control:
• Especially if DC current - may have been ejected
• Breathing:
• AC current may paralyse thoracic muscles
• Circulation:
• Hypovolaemia from concurrent injuries likely
• ECG - assess for presence of sinus rhythm, and remember to check the QT interval
• Cannulate in a limb not involved in the current pathway 
• There may be damage to vascular structures that will stop systemic circulation
• Disability: 
• Look for entry and exit burns
• Cool burns as appropriate 
• Remove smouldering clothes, shoes and belts. 
• Exposure: 
• Look for compartment syndrome (if you don't look you won't see!)
• Bloods for:
• FBC, U&E (hyperkalaemia secondary to rhabdomyolysis likely)
• Phosphate
• Calcium
• CK
• Group and Save
• Role of troponins is unclear 
•  Check hearing
• Risk of ruptured ear drums from lightening (Oxford Handbook of Emergency Medicine)
• Urinalysis - check for blood
• Observe
• Six hours of being asymptomatic
• Send home
• Asymptomatic patients with 
• domestic and minor low voltage burns
• normal ECG
• no history suggestive of arrhythmia
• no myoglobinuria
• Admit
• Children who bite electrical flexes
• risk of delayed bleeding
•  All patient with high voltage conduction injuries, or abnormalities found.
• Follow Up 
• Delayed cataract formation 
• Neuropsychiatric problems
• Compartment syndrome advice

The management of burns is important - we'll cover this later!

Hypothermia

We're all used to deliberately inducing hypothermia in patients who have had an arrest, or similar - but not so used to treating hypothermia. For a good environment based start to your hypothermia training, there are plenty of Wilderness Medicine and Polar Medicine courses about.

EnlightenMe has got a lot of resources on hypothermia. Most of them are about adults, but that is better than nothing! e-LfH has a module on hypothermia too. We have some learning about ECG changes, a CEMPedia article, CEMPedia on cardiac arrest in special circumstances. BMJLearning has two modules - hypothermia for Paramedics and accidental hypothermia which has an excellent list of things that predispose people to hypothermia. LITFL also talks about ECG changes, as does Circulation- the height of the Osbourn wave is proportional to the degree of hypothermia.

There is a podcast here, a LITFL summary, and an abbreviation heavy summary here on crashing patient. There is an excellent summary here on Academic Life in Emergency Medicine. There are also some well thought of videos here.

For those who are wondering whether it's all worth it or not, there is a brilliant video about a hypothermia survivor.

Statistics
In Great Britain, hypothermia cases are estimated at 6-8 patients per 1000 patients Most cases of hypothermia occur in an urban setting and are related to environmental exposure attributed to alcoholism, illicit drug use, or mental illness, often exacerbated by concurrent homelessness.

Primary hypothermia usually affects young males and infants. Secondary hypothermia usually affects patients who are elderly, homeless, mentally ill, victims of trauma, or have multiple co-morbidity.

Older adults are at risk of hypothermia as a consequence of:

• A reduced ability to recognise and respond to lower ambient temperature, compared with younger adults. 
• An impaired peripheral vasoconstrictor response to cold.
• A lower basal metabolic rate compared with younger adults. 
• Falls, which are common in older people can result in prolonged periods lying on the floor, allowing heat loss by conduction.

Signs and Symptoms
There are plenty of signs and symptoms of hypothermia - some of which are subtle, others aren't.
Shivering
Impaired judgement
Confusion
Tachycardia
Tachypnea

Bradycardia
Respiratory depression
Hyperglycaemia
Dysarthria
Ataxia

Stupor
Lethargy
Osbourne Waves on the ECG - ( Osborn or J waves on the ECG. The upward deflection of the terminal S wave)
Loss of reflexes
Hypotension
Asystole

Treatment

• ABCD approach
• Handle carefully
• In general, the hypothermic patient is dehydrated and fluid depleted consider a fluid challenge of warmed 0.9% saline or dextrose-saline as they may also be hypoglycaemic. Hartmann’s is best avoided as the hypothermic liver can't metabolise lactate. 
• Passive Rewarming
• Active Rewarming
• Core Rewarming - IV fluids and warm, humidified oxygen
• Extracorporeal Blood Rewarming

In cardiac arrest
 - Total of three shocks (if indicated) until core temperature greater than 30degrees.
 - No drugs under 30degrees, then given with twice the time interval until normothermia
 - Chest compressions may be harder work.

Investigations
Urea & electrolytes
Full blood count
Clotting screen,
Arterial blood gas
Creatinine kinase level
Calcium
Magnesium
Amylase

Drowning

Drowning and near drowning is a fascinating area. As a dinghy sailor, I regularly teach about drowning on our first aid courses, but as we sail on top of the water and not in the water, I've still never seen it! If you get a chance to watch the Cold Water Casualty video, it is well worth a watch. The Royal Yachting Association has a good summary about cold shock, hypothermia and drowning. The RNLI provides some UK statistics. Drowning is specifically mentioned in the cardiac arrest competencies, and in HAP11 Environmental emergencies (an adult competency).

WHO provides us a statistical summary about drowning, and Update in Anaesthesia provides a very thorough overview as does BMJ best practice, LITFL, EP monthly and the AHA.

There is an e-learning module on drowning here and here. Unless you are a Paramedic you're unlikely to have access to the former, and there are so many alternative resources out there I wouldn't subscribe. Enlighten me has an excellent CEMPedia article on drowning  and an adult case.


Statistics
Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid. In 2000, there were 409,272 deaths from unintentional drowning worldwide, decreasing slightly in 2004 to an estimated 388 000. 150 people drown in the UK coast every year - and 80% of these are male. Drowning is the second highest cause of death from injury, after road traffic injuries.

Young children are at risk as they are unaware of the dangers and less able to escape from water once submerged.

Things Drowning Causes
There are four main problems drowning causes:

• Hypothermia and Cold Water Shock
  Not everyone drowns in warm water! Hypothermia causes its own special problems. The most relevant problem is that blood gets diverted in to the core of the body - causing chilly blood outside, and warm blood inside. When you start to mix the warm and chilly blood, the body gets a bit confused - and arrhythmias can occur.
  Cold shock can happen at any water temperature below fifteen degrees - the average UK water temperature is twelve degrees.
• Associated injuries
  Remember to think about what people injured when they drowned themselves - neck and c-spine injuries are common.
  Awareness of injuries will be low because of natural adrenaline, and vasoconstriction in the extremities.
• Water aspiration
  As you hit the water, before the diving reflex is triggered, you get a gasp reflex (as you do when you first get in a really cold swimming pool!). If you enter turbulant water, as waves crash overhead you are even more likely to inhale some water. Aspiration of even small amounts of water significantly impairs gas exchange. The water dilutes and inactivates surfactant, so alveoli are prone to collapse. The water can also cause direct lung injury.
• Post rescue Collapse
  Loss of hydrostatic pressure of water on the body results in loss of peripheral resistance and venous pooling. Patients should be extricated from the water in a horizontal position.
• Post Drowning Infection
  Some people contract infections after drowning. Swamp water might cause fungal infection (aspergillosis)- so think about it in your poorly patients. Stagnant water with rat urine may cause Weil's disease (Leptospirosis). There are many case reports (1 2 3) about pneumonia after drowning - but there is still no evidence for prophylactic antibiotics.

Investigations
- ABG if significant history of submersion as saturations may not be reliable.
- CXR
- ECG - look closely for a prolonged QTc.
- Core temperature measurement
- Electrolytes and BM
- Blood culture in patients with significant aspiration

Treatment

• ABCD approach
• For children, no modifications to the resuscitation sequence are recommended.
• If intubation needed, ventilate using an ARDS protocol. 
• Observe for  at least six hours.
• After discharge, written discharge advice is well received by families. 
• There is no evidence to support giving prophylactic antibiotics on discharge.