Chapter 12: Resuscitation in Special Circumstances Flashcards
What happens to potassium in acidosis?
Serum K+ increase as it moves from cells to serum
H+/K+ pump
How is hyperkalaemia defined and what classifies as severe?
K+>5.5mmol/L
Severe >6.5mmol/L
What can cause hyperkalaemia?
Renal failure
Acidosis
DKA
Drugs - Spironolactone, ACEi, amiloride, ARB, NSAID’s, B blockers, trimethoprim
Endocrine - Addison’s disease
Tissue breakdown - rhabdomyolysis, TLS, haemolysis
How may hyperkalaemia present?
Arrhythmia
Weakness –> flaccid paralysis, paraesthesia, depressed tendon reflexes
What ECG changes do you see with hyperkalaemia?
Absent/small p waves Long PR Tall tented t waves Wide QRS Can see ST segment depression
S and T merging
VT
Bradycardia
Cardiac arrest
How is hyperkalaemia treated?
STOP DRUGS/K+ fluids
- IV Calcium chloride - 10ml/10% over 2-5 mins
- Insulin/Dextrose - 10 units in 250ml of 10% 15-30min
- Sodium bicarbonate - 50mmol IV bolus - severe acidosis or renal failure
- Salbutamol nebulised 10-20mg
- Dialysis
- K+ binder - calcium resonium 15-30g or Sodium Polystyrene Sulfonate
What do you do for each stage of hyperkalaemia?
Mild: 5.5-5.9
- Address cause
- Calcium resonium or sodium polystyrene sulfonate
Mod: 6.0-6.4
- Insulin dextrose
- as above
Severe: 6.5+
- Expert help
- Calcium chloride
- Shifting agents
- Remove K+ - dialysis
What are the main risks associated with hyperkalaemia treatment?
Hypoglycaemia - monitor BM
Tissue necrosis - secondary to extravasation of intravenous calcium salts - Ensure secure vascular access
Intestinal necrosis and obstruction - K+ exchange resin - avoid prolonged use and give laxative
Rebound hyperkalaemia - after drug treatment warn off - monitor for at least 24hr
What is important to know about cardiac arrest in haemodialysis patients?
Sudden cardiac death most common cause Usually ventricular arrhythmia Stop ultrafiltration, give fluid and return pt blood volume Disconnect dialysis machine Use dialysis access for drugs Early defib
How is hypokalaemia defined?
<3.5mmol/L
Severe = <2.5mmol/L
What can cause hypokalaemia?
GI losses Alkalosis Drugs - loop diuretics, thiazides, laxatives, steroids Renal losses Cushings/hyperaldosteronism Mg depletion Poor intake
Overtreated High K+
How can you recognise hypokalaemia?
- Rule out in all arrhythmia/cardiac arrest
- Seen at end of haemodialysis or in peritoneal dialysis
Symptoms: - Fatigue
- Weakness
- Leg cramps
- Constipation
If severe:
- Rhabdomyolysis
- Ascending paralysis
- Resp difficulties
What ECG features are seen in hypokalaemia?
U waves Small t waves ST segment changes Arrhythmia's Cardiac arrest
How should K+ be replaced?
Gradually
Max 20mmol/L per hour
More rapid infusion indicated in unstable arrhythmia - 2mmol/L/min for 10 mins then 10mmol over 5-10 mins
What can cause hypercalcaemia?
Primary/tertiary hyperparathyroid
Malignancy
Sarcoid
Drugs
How does hypercalcaemia present?
Confusion Weakness Abdo pain Hypotension Arrhythmia Cardiac arrest
What ECG changes are seen in hypercalcaemia?
Short QT Wide QRS Flat t waves AV block Cardiac arrest
How is hypercalcaemia treated?
Fluid replacement Furosemide - 1mg/kg Hydrocortisone 200-300mg Pamidronate 30-90mg Treat underlying cause
What can cause hypocalcaemia?
Chronic renal failure Pancreatitis Calcium channel blocker OD Toxic shock syndrome Rhabdomyolysis TLS
How does hypocalcaemia present?
Paraesthesia Tetany Seizures AV block Cardiac arrest
What ECG changes are seen for hypocalcaemia?
Prolonged QT
T wave inversion
Heart block
Cardiac arrest
What can cause hypermagnasaemia?
Renal failure
Iatrogenic
How does hypermagnasaemia present?
Confusion Weakness Resp. depression AV block Cardiac arrest
What ECG changes are seen for hypermagnasaemia?
Prolong PR and QT
T wave peak
AV block
Cardiac arrest
How is hypermagnasaemia managed?
Calcium chloride 10ml 10%
Ventilatory support if req.
Saline diuresis - furosemide 1mg/kg+0.9% saline
Haemodialysis
What can cause hypomagnasaemia?
GI loss Polyuria Starvation Alcohol Malabsorption
How does hypomagnasaemia present?
Tremor Ataxia Nystagmus Seizures Arrhythmia - torsades Cardiac arrest
How does hypomagnasaemia present on ECG?
Prolong PR and QT ST depression T wave inversion Flat p waves Wide QRS Can get polymorphic VT - torsades
How is hypomagnasaemia managed?
2g 50% MgSo4 (4ml 8mmol/L)
- severe = over 15 mins
- torsades = over 1/2 mins
- Seizure = over 10 mins
How is septic shock defined?
Lactate >4mmol/L
Hypotension unresponsive to fluid resus
50% mortality
What are the common causes for mortality in poisoning?
Airway obstruction and respiratory arrest secondary to decreased conscious level - early tracheal intubation
Drug induced hypotension - usually respond to IV fluids but may need vasopressor support
Electrolytes, BM and ABG’s should be checked as they commonly cause mortality
What modifications are required to resus in poisoning?
Avoid mouth to mouth breathing in presence of cyanide, hyrogen sulphide, corrosives and organophosphates
Check for hypo/hyperthermia
Be prepared for long resus time and consider ECLS
Seek expert advise and consult TOXBASE
Focus on correcting hypoxia, hypotension, acid/base and electrolytes
What specific treatments are available for poisoning?
Skin exposure - remove clothes
Gastric lavage and laxatives not used
Activated charcoal - <1hr and intact airway. Useful for carbamazepine, dapsone, phenobarbital, quinine and theophylline
Whole bowel irrigation using polyethylene glycol - sustained release/enteric coated drugs, oral iron poisoning, removal of ingested packets illicit drugs
Sodium Bicarb IV - salicylate poisoning
Haemodialysis - Drugs with low molecular weight, low protein binding, small volume of distribution, high water solubility
Specific antidotes
What is the specific antidote for paracetamol?
N-acetylcysteine
What is the specific antidote for organophosphate poisoning?
High dose atropine
What is the antidote for cyanides poisoning?
Sodium nitrite
Sodium thiosulphate
Hydroxocobalamin
Amyl nitrite
What is the antidote for digoxin poisoning?
Digibind - digoxin specific Fab antibodies
What is the antidote for benzodiazepines?
Flumazenil if no risk of seizure
What is the antidote for opioid poisoning?
Naloxone 400mcg IV, 800mcg IM, 800mcg SC or 2mg Intranasal
Non IV may be quicker - save time getting access
Duration of action not as long as respiratory depression persist - give increments until breathing adequately
What does opioid poisoning cause?
Resp depression
Pinpoint pupils
Coma following resp. arrest
What happens if opioids are withdrawn acutely in poisoning?
State of sympathetic excess leading to complications:
- Pulmonary oedema
- Ventricular arrhythmia
- Severe agitation
Use naloxone cautiously in patients with dependence
What can a benzodiazepine OD cause?
Loss of consciousness
Respiratory depression
Hypotension
What can reversal of benzodiazepine OD with flumazenil lead to in patients with dependence or have coinjested pro-convulsants?
Seizure
Arrhythmia
Hypotension
Withdrawal syndrome
Is flumazenil used in comatose patients?
No
What can tricyclic antidepressant OD cause?
Hypotension
Seizure
Coma
Life-threatening arrhythmia - commonly shockable
Anti-cholinergic effects - mydriasis, fever, dry skin, delirium, tachycardia, ileus, retention
What may indicate that a TCA overdose will lead to arrhythmia?
Wide QRS
Right axis deviation
Consider sodium bicarb
When can you get local anaesthetic toxicity?
Regional anaesthesia - enters artery or vein
What issues can you get with local anaesthetic toxicity?
Severe agitation
Loss of consciousness with or without tonic-clonic convulsions
Sinus Bradycardia/ Conduction blocks/Asystole/VT
How can local anaesthetic toxicity be treated?
Resus measures
IV 20% lipid emulsion
- initial 1.5mL/kg/hr bolus in 1 min followed by 15mL/kg/hr infusion
- Give upto 3 boluses at 5 min intervals
- Max 12mL/kg emulsion
What should you do following lipid emulsion rescue for local anaesthetic toxicity?
Exclude Pancreatitis - daily amylase or lipase assays for 2 days
Safe. transfer to clinical area
Report cases to National Patient Safety Agency
What can cocaine toxicity cause?
Sympathetic overstimulation:
- agitation
- symptomatic tachycardia
- hyperthermia
- hypertensive crisis
- myocardial ischaemia with angina
What can be done to treat cocaine toxicity?
Small dose IV benzo (midazolam, diazepam, lorazepam)
GTN and phentolamine - reverse coronary vasoconstriction
Can consider beta blockers and anti-arrhythmics - best unclear
Use normal adrenaline dose if arrest
How is drug induced severe bradycardia managed?
Atropine - organophosphate, carbamate, nerve agent poisoning or acetylcholinesterase inhibitors
2-4mg IV repeated doses
What can be used to treat bradycardia due to beta blockers or calcium channel blockers?
Can use Isoprenaline at high dose if refractory bradycardia due to beta blockers
Vasopressors, inotropes, calcium, glucagon, phosphodiesterase inhibitors and high dose insulin-dextrose-potassium infusions
Which asthmatic patients are at highest risk for near fatal attacks?
- Hx of req. intubation and mechanical ventilation
- Hospitalisation/emergency care in last year
- Low or no use of inhaled ICS
- Increased use/dependence on SABA
- Anxiety, depression and/or poor compliance
- Food allergy
What can cause cardiorespiratory arrest in asthmatic patients?
- Severe bronchospasm and mucous plugging –> asphyxia
- Hypoxia –> cardiac arrhythmia. Can also be due to drugs or electrolyte abnormalities
- Dynamic hyperinflation in mechanically ventilated - reduced venous return and BP
- Tension pneumothorax
What signs indicate acute severe asthma?
- PEFR 33-50%
- RR >25
- HR >110
- Inability to complete sentence in 1 breath
What signs indicate life-threatening asthma?
Altered conscious level Exhaustion Arrhythmia Hypotension Cyanosis Silent chest Poor resp effort
PEFR<33
SpO2 <92%
PaO2 <8kPa
‘normal’ PaCO2 - 4.6-6
What indicates asthma mat be near fatal?
Raised PaCO2 and/or mechanical ventilation with raised inflation pressures
What may absence of wheezing in asthma indicate?
Critical airway obstruction
Increased wheezing may indicate + response to therapy
What can happen to SpO2 in SABA therapy of asthma?
May initially decrease as beta agonists cause bronchodilation and vasodilation - increased intra pulmonary shunting
How can acute asthma attacks be managed?
- High flow O2 - sats of 94-98%
- Salbutamol 5mg neb - repeat every 15-30 mins or cont. 5-10mg/hr
- Add neb ipratropium bromide 500mcg 4-6hr
- Prednisolone 40-50mg PO or hydrocortisone 100mg IV
Can give IV Magnesium sulphate 2g (8mmol) over 20 mins
Consider IV salbutamol 250mcg if inhaled not possible
Senior advice for aminophylline - 5mg/hr IV 20 min then 500-700mcg/kg/hr infusion (max dose 20mcg/mL to avoid toxicity)
What can beta agonist and steroid therapy in asthma cause?
Hypokalaemia - correct
When should tracheal intubation and controlled ventilation be considered in asthma?
Deteriorating peak flow Reduced conscious level Persisting/worsening hypoxaemia Worsening resp. acidosis Severe agitation, confusion and fighting against o2 mask Progressive exhaustion Cardioresp. arrest
Role of non invasive ventilation unclear - only considered in ICU setting
How is ALS modified in acute asthma?
- Intubate early - high risk of GI inflation and hypoventilation if ventilate without tracheal tube
- RR 10 breaths and normal tidal volume
- If dynamic hyperinflation - compress chest wall + disconnect tracheal tube
- Be aware of tension pneumothorax
- Consider extracorporeal life support
Which 3 criteria are indicative of anaphylaxis?
1 Sudden onset and rapid progression of symptoms
2 Life threatening airway and/or breathing and/or circulatory problems
3 Skin and/or mucosal changes - flushing, urticaria, angioedema
What is important to remember about recognising anaphylaxis?
Skin and mucosal changes alone not a sign
Skin and mucosal changes can be subtle/absent
Can be GI symptoms
How is anaphylaxis managed in an adult?
Remove trigger Lie down IV Fluid challenge 500-1000ml IV chlorphenamine 10mg IV hydrocortisone 200mg IM Adrenaline 0.5mg (0.5ml of 1:1000) - anterolateral middle thigh
How is anaphylaxis managed in children?
Fluids:
- Crystalloid 20ml/kg
Child 6-12:
- IM adrenaline 0.3mg
- IV chlorphenamine 5mg
- IV hydrocortisone 100mg
Child 6 month to 6 yo:
- IM adrenaline 0.15mg
- IV chlorphenamine 2.5mg
- IV hydrocortisone 50mg
Child <6 months
- IM adrenaline 0.15mg
- IV chlorphenamine - 250mcg/kg
- IV hydrocortisone 25mg
When can IV adrenaline be used in anaphylaxis?
Only by specialists
Can cause hypertension, tachycardia, ischaemia, arrhythmia if spontaneous circulation
May be used if repeated IM doses
Max 50mcg in adults and 1mcg/kg in children
How can anaphylaxis be investigated?
Mast cell tryptase - 3 timed samples:
- ASAP after resus
- 1-2hr after start of symptoms
- 24hr after
What can cause cardiac arrest in pregnancy?
Cardiac disease PE Psychiatric disorders Hypertensive disease - eclampsia/pre-eclampsia Sepsis Haemorrhage Amniotic fluid embolus Ectopic
How do you initially treat a distressed/compromised pregnant patient?
Left lateral position/manually displace uterus - relieve pressure on IVC
High flow O2
Fluid bolus
How is cardiac arrest management modified in pregnancy?
Summon help immediately
Start CPR - hand may be slightly higher
Establish IV access above diaphragm
Manually displace uterus/left lateral tilt 15-30 degrees
Prep for C-Section
Early tracheal intubation
May need alternative pad positions for defibrillation
How is haemorrhage in pregnancy managed in cardiac arrest?
Fluid Resus
Tranexamic acid and correct coagulopathies
Oxytocin, ergometrine, prostaglandins and uterine massage for uterine atony
Uterine compression sutures, packs or intrauterine balloon devices
Surfical control - aortic cross clamp/compression and hysterectomy. Placenta percreta may req. intra-pelvic surgery
How is pre-eclampsia treated?
Magnesium sulphate - prevent eclampsia in labour
How are amniotic fluid emboli managed?
Supportive
Correct coagulopathies
Should fibrinolysis be given in PE in pregnancy?
Must be carefully considered
If diagnosis suspected and maternal cardiac output can’t be restored then yes
When is peri-mortem C-section considered?
<20 weeks - not considered
20-23 weeks - Initiate emergency delivery to permit successful resus of mother not for survival of infant
>24 weeks - initiate for both mother and infant
What is important in post resus care for pregnant patients?
Targeted temperature management with fetal heart monitoring
ICD’s can be used
What are the key causes of cardiac arrest in trauma patients?
Severe traumatic brain injury Hypovolaemia Hypoxia Tension pneumothorax Direct injury to vital organs Cardiac tamponade
What is commotio cordis?
Actual or near arrest caused by blunt impact to chest wall over the heart
If coincide with t wave, can lead to VF
What factors are associated with survival from traumatic cardiac arrest?
Presence of reactive pupils Duration of CPR Pre-hospital time Organised ECG rhythm Respiratory activity
Prolonged CPR - poor outcome (stop. after 20 mins if no response)
What is a key focus of traumatic cardiac arrest management? What may be helpful to use in these cases?
Correct the reversible causes
Do chest compressions but unlikely to be successful without correction
FAST scan or CT may be useful in guiding treatment
Early tracheal intubation can be beneficial
What can happen if positive pressure ventilation is used in low cardiac output conditions?
Further circulatory depression by impeding venous return
How are tension pneumathoraces managed in traumatic cardiac arrest?
Bilateral thoracotomies
5th intercostal space mid axillary line
Can extend to clamshell thoracotomy if req
Needle decompression is a v temporary measure
How is a cardiac tamponade managed?
Resuscitative clamshell thoracotomy
Needle aspiration unreliable - pericardium commonly full of clotted blood
When should resuscitative thoracotomies be considered?
Penetrating torso trauma and <15min CPR
Blunt trauma and <10min prehospital CPR
No pulse after penetrating chest or cardiac injuries and signs of life or ECG activity
What are the commonest causes of anaesthesia related cardiac arrest?
Airway management
What are the most common rhythms seen in peri op cardiac arrest?
Asystole - 41%
VF - 35%
What is important about the management of periop cardiac arrest?
Use fluid warmers and forced air warmers
PEA may not be immediately detected - use low end tidal CO2 to provoke pulse check
CPR is ideal in supine position but possible prone
Consider open cardiac compressions if heart easily accessed
Give pre-cordial thump if no immediate access to defib
Stop surgery in asystole or extreme Brady - likely excess vagal activity - atropine 0.5mg
If adrenaline, give dose in 50-100mcg increments instead of 1mg bolus. If no response then further 1mg boluses
What is key to know about cardiac arrest following cardiac surgery?
Relatively common
Recognition of need to perform resteronomy early is key - tamponade or haemorrhage
External compressions may cause sternal disruption and cardiac damage
Use adrenaline v cautiously and titrate to effect IV upto 0.1mg
When is emergency resternotomy indicated?
Adequate airway and ventilation
3 shock attempts in VF/pVT
Asystole/PEA
Do resternotomy without delay. Ideally within 5 mins of arrest
Should you do external chest compressions in cardiac arrest following cardiac surgery?
Yes start immediately if no output
Verify effectiveness using arterial trace - systolic of >60 and diastolic >25. HR 100-120
If not reaching targets, resternotomy
What is drowning and what are the “types”?
Respiratory impairment from submersion/immersion in liquid
Submersion - face underwater/covered by water
Immersion - head remain above water - e.g. life jacket
What typically happens to patients who are immersed in water?
Become hypothermic
Airway remain patient
Water splashes can cause aspiration
What happens in submersion?
Patient initially hold breath and swallow water
As pt. become hypoxic and hypercapnic, breath holding reflex and laryngospasm reflex lost. Patient aspirate water
Laryngospasm reflex prevent water entering lungs
Bradycardia due to hypoxia occur before sustaining cardiac arrest
How should you correct hypoxaemia following submersion?
Ventilation only resus
How do you attempt to rescue someone from the water?
Ideally throw rope or buoyant rescue aid
Assess risk and enter with flotation device
If submersion for <10 mins - likely good outcome. If >25 mins - likely poor outcome
Remove from water horizontally - spinal precautions rarely necessary
Why remove patients horizontally from the water?
Hypovolaemia after prolonged immersion can cause cardiovascular collapse and arrest
When are spinal precautions necessary in water rescue?
Diving in shallow water Signs of severe injury water side Water skiing Kite surfing Watercraft racing
If pulseless and apnoeic - remove asap while limiting neck movement
What initial rescue should you do for patients once retrieved from the water?
Check for response
Give 5 rescue breaths with supplemented oxygen
Start SPR as normal
If lots of foam - continue CPR until intubation
Turn victim to side and remove regurgitation material
What modifications can be made to ALS after drowning?
Use PEEP and NG stomach decompress in drowning pt who hasn’t arrested or achieved ROSC
Check ECG and end tidal CO2 for signs of life. Consider echo (pulse not sufficient)
Give rapid IV fluid - pt. become hypovolaemic due to cessation of hydrostatic pressure from water
What is important about post resus care after drowning?
Risk of developing ARDS - use standard protective ventilation stratefies
Consider ECMO for refractory cardiac arrest, hypoxaemia and submersion in ice cold water
Pneumonia common however prophylactic Abx only if sewage/grossly contaminated
Neurological outcome determined by hypoxia
Define hypothermia
<35 degrees
Mild = 32-35
Mod = 28-32
Severe = <28
What happens in each stage of hypothermia?
I Mild - shivering, conscious
II Mod - stop shivering, conscious,
III Severe - decreased consciousness, vitals present (28-24)
IV - unconscious, vitals not present <24
V - death due to irreversible hypothermia <13.7
What may increase risk of hypothermia?
Things that decrease conscious level - drugs, alcohol, illness, exhaustion, neglect
Factors that impair thermoregulation - elderly and very young
Where is a core body temperature taken from?
Lower third of oesophagus
How much does hypothermia reduce oxygen demand?
6% reduction per 1 degree
Why must you be careful diagnosing death in hypothermic?
Patients can have slow small volume irregular pulses and low BP but they may return once warm
Not dead until warm and dead
At 18 degrees, brain survive 10 times as long from circulatory arrest than at 37
Good survival has been reported in arrest and core temp of 13.7 degrees after immersion for 6.5 hours with CPR in adults
How should CPR be modified in hypothermic patients?
<28 degrees 5 min CPR, 5 min break
<20 5 min CPR, 10 min break
Check for pulse for 1 minute - central artery and ECG
Consider using mechanical chest compression
Dont delay intubation
Hold adrenaline and amiodarone until >30 degrees. Then double dose interval (6-10 mins) until 35 degrees
How are arrhythmia’s treated in hypothermia?
Sinus Brady –> AF –> VF –> asystole
Apart from VF, others revert spontaneously as temp increase. Cardiac pacing not indicated unless haemodynamic compromise persist after rewarming
Stop shocks after 3 until temp >28-30
How are patients rewarmed after accidental hypothermia?
Remove from cold and take off wet clothes
stage II and worse - immobilise, handle carefully, oxygenate, dry and give clothes, heat packs
Stage I - mobilise as rewarm - exercise rewarm patient
Patients continue to cool after removal from cold environment - faster if stage II or worse
Where should hypothermic patients be taken?
Stage I - nearest hospital
II - IV - Nearest hospital with ECMO facilities
V - Consider whether to withhold CPR, if not nearest hospital with ECMO
What are the reasons to terminate CPR in a hypothermic patient?
DNACPR Obvious sign of irreversible death Unsafe for rescuer Avalanche burial for >60 min Airway packed with snow Asysole
When are avalanche victims not likely to survive?
Buried for >60 mins and in cardiac arrest with obstructed airway on extraction
Buried and in cardiac arrest with K+ >8mmol/L
When can extracorporeal life support rewarming be considered?
Temp <32
K+ <8mmol/L
Veno-arterial ECMO preferred as more rapidly available, less anticoagulation, provide prolonged cardioresp support after rewarming
What other active rewarming techniques can be used?
Forced warm air
Warm infusions
Forced peritoneal lavage
What are the stages of hyperthermia?
Heat stress
Heat exhaustion
Heat stroke –> multi-organ dysfunction and cardiac arrest
What is heat stroke?
Core temp >40.6
Change in mental state
Varying levels of organ dysfunction
2 types:
- exertional
- non exertional - elderly in heat waves
What can predispose someone to heat stroke?
Elderly:
- underlying illness
- medication use
- declining thermoregulatory mechanisms
- limited social support
Lack of acclimitisation Dehydration Alcohol Obesity CVS conditions Skin disease Hyperthyroidism Phaeochromocytoma
What drugs can predispose to hyperthermia?
Anticholinergics Diamorphine Cocaine Methamphetamine Phenothiazines Sympathomimetics Ca2+ blockers Beta blockers
What are the features of heat stroke?
Core Temp >40 Hot dry skin Fatigue, headache, fainting, facial flush, D&V CVS dysfunction - arrhythmia and hypotension Resp dysfunction - ARDS CNS dysfunction - seizures and coma Liver and renal failure Coagulopathy Rhabdomyolysis
What differentials do you have to consider for raised core temperature?
Drug withdrawal syndromes Neuroleptic malignant syndrome Sepsis CNS infection Endocrine disorder - thyroid and phaeochromocytoma
How is heat stroke treated?
Rapid cooling
Haemodynamic monitoring - fluid and electrolytes
Defibrillation as normal
Post resus care as normal
How do you cool a patient in heat stroke?
Simple - cool drinks, take off clothes, fan, spray tepid water, ice packs over groin, axilla neck
Immerse in cold water - can cause vasoconstriction, preventing heat dissipation
Advanced - cold IV fluids, intravascular cooling catheters, ECMO
Diazepam for seizures
What is used in treatment of malignant hyperthermia?
Dantrolene
What factors influence severity of electrocution injury?
AC/DC current Voltage Magnitude fo energy Resistance to current flow Pathway of current Area and duration of contact
What reduces skin resistance to electrocution?
Moisture
What is most likely to be damaged in electrocution?
Conductive neuovascular bundles
What does contact with AC current lead to?
Tetanic contract of skeletal muscle
What can cause myocardial or respiratory failure in electrocution?
Resp arrest due to paralysis of respiratory muscles or resp depression
Current can precipitate VF if it crosses myocardium during vulnerable period.
Current can cause coronary artery spasm
Asystole ma be primary or secondary to asphyxia following resp arrest
What current direction is more likely to be dangerous?
Current that transverse myocardium
Transthoracic pathway (hand to hand) more likely to be fatal than vertical (hand - foot) or straddle (foot - foot)
In patients who survive an initial electric shock, what may happen?
Catecholamine release or autonomic stimulation:
- tachycardia
- hypertension
- prolonged QT and transient t wave inversion
- myocardial necrosis
- CK release
How are lightning strikes and electrical injuries treated?
Early intubation - airway management may be difficult if burns
Ventilatory support if muscle paralysis persist
Use standard defibrillation guidelines
Remove smouldering clothing and shoes to prevent thermal injury
IV fluids if tissue destruction - good urine output
Early surgery if req.
Check for compartment syndrome
What arrhythmia is most likely to be seen in an electrocution?
AC - VF
DC - Asystole
What determines long term prognosis for electrical injury?
Severe burns
Myocardial necrosis
Extent of CNS injury
Multiple system organ failure
