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I struggled to find PEM resources for my CT3 year, despite the variety of excellent resources out there. I hope this website will help point you in the right direction. I'm not a PEM expert, but am following the guidance CEM have issued (in the form of a syllabus) to put together this page. This page is not endorsed by CEM, and any mistakes are mine.

Please comment with corrections, additions and further suggestions.

All the information here is collected from the internet, and it might be out of date or inaccurate, so please use your judgement and adhere to your hospital's protocols. If you do notice any errors or omissions please comment so we can put them right!

To navigate, decide whether you want to start with a PMP or a PAP. You can then select which PMP or PAP you want to look at. You will then be taken to the summary page for that PMP, with links expanded topic collections. If you know what topic you want to look at already, click on the link on the right hand side.

Monday, 12 August 2013

Cardiac Arrest Drugs

PMP 3 states we should:
"Understand the pharmacology, indications and contraindications, dose calculation and routes of administration of drugs used in resuscitation and the stabilisation of children in cardiac arrest."

Where better to start looking for resources on this kind of thing than in the anaesthetic literature?

Adrenaline
There is an anaesthetic FRCA tutorial here, which probably covers everything we need to know. It tells us similar things to LITFL. LITFL have a good summary here and here.
  • Naturally occurring catecholamine 
  • Hormone and a neurotransmitter
  • Broken down by monoamine oxidase (MAO) and catechol-O -methyltransferase (COMT).
  • Comes in 1:1000 strength (in vials) or 1:10000 (mini-jets)
  • Acts non selectively at all the adrenergic receptors (α1, α2, β1, β2, β 3)
    • At low doses the beta effects predominate - increase heart rate
    • At high doses the alpha effects predominate
  • Produces the flight or fight response (sympathomimetic)
  • Causes 
    • increased heart rate
    • increased contractility
    • vasoconstriction and vasodilation
    • bronchodilation
    • glycogenolysis
    • smooth muscle relaxation
  •  Side effects are normally because of overdose or inappropriate use. 
    • Dizziness
    • Palpitations
    • Tremour
    • Arrhythmias
    • Hypertension
    • Cerebral haemorrhage
    • Acute pulmonary oedema
    • Lactic acidosis
    • Hyperlactaemia - with long term use
    • Hyperglycaemia - with long term use
  • Caution
    • At all times: big effects on the cardiovascular symptoms
    • In patients with arrhythmias, hypertension or ischaemic heart disease
    • Care in patients taking Mono-Amine Oxidase Inhibitors
  • Uses
    • Cardiac Arrest: 1mg every 3-5 minutes, after 3rd shock. 10mcg/kg in children
      This is in the guidelines, but its use is still controversial
    • ROSC use 1: 100 000 to support BP if needed 
    • Anaphylaxis: Adult or > 12 500mcg IM or 50mcg IV titrated to effect if experienced in use.
      6- 12 years: 300mcg IM or 1mcg/kg IV titrated to effect
      <6: 150mcg IM or 1mcg/kg titrated to effect
    • Inotropic support: continuous infusion via central line with invasive BP monitoring
      • 4mg adrenaline diluted to 50ml in  saline or glucose
    • Severe croup: 
      •  0.5 ml/kg of a 1:1000 solution (maximum of 5 ml)
    • Topical or local vasoconstriction
      Remember:
      1ml of 1:1000 = 1 mg
      1ml of 1:10 000 = 0.1 mg = 100 mcg
      1ml of 1:100 000 = 0.01 mg = 10 mcg
Amiodarone
CV pharmacology has a good summary with some pretty pictures. LITFL has a good summary and a more pharmacology focused tutorial - they do state that efficacy of amiodarone in paediatric children hasn't been established.
  • Membrane stabilising anti-arrhythmic drug
  • Increases the duration of the action potential
  • Slows AV conduction
  • Mild negative inotropic effect
  • Causes peripheral vasodilation because of alpha-blocking effects
  • The solvent with it causes histamine release.
  • 25 - 60 days half life
  • Class I, II, III & IV actions
  • Generally considered a Class III arrhythmic drug
  • Dose:
    • 5mg/kg after third shock in shockable rhythms
    • Repeat the dose after the fifth shock
    • Central vein if possible - causes thrombophlebitis
  • Side effects
    • Pulmonary fibrosis
    • Thyroid problems
    • Can cause hypotension
    • Can cause Bradycardia and AV Block
    • Can cause liver enzyme elevations
    • May be arrhythmogenic
Atropine
There aren't so many summaries on atropine - probably because it's been taken out of the resus algorithm. There's something on CV pharmacology, LITFL summary and a page on the non resuscitation uses- Death Rattle.
  • Atropine is a muscarinic receptor antagonist and bind to muscarinic receptors. 
  • Stops ACh from binding
  • So stops the effects of vagal nerve activity on the heart
  • Administration of less than 500mcg in adults and less than 100mcg in children can produce a paradoxical bradycardia because of the central or peripheral parasympathomimatic effects of low dose.
  • Atropine rapidly crosses the placenta
  • Atropine crosses the blood-brain barrier
  • Side effects:
    • tachycardia
    • pupil dilation
    • dry mouth
    • urinary retention inhibition of sweating
    • blurred vision 
    • constipation
  • Contraindicated in patients with: 
    • glaucoma, 
    • pyloric stenosis and 
    • prostatic hypertrophy
  • Uses
    • Bradycardia - as per algorithm (adults and children 1 2 3)
      • May be caused by poisoning
      • Conduction disorder (pathway abnormality or Long QT)
      • Cardiomyopathy
    • Excessive secretions
  • Dose
    • 10mcg/kg
Magnesium
Magnesium is a panacea for everything at the moment. There is a summary article here, BNF entry here and a LIFFL summary. There are some good flashcards for Paramedics here. AAFP has got an interesting simply written article about magnesium.
  • Extracellular cation
  • Depressant effect on the release of catecholamines
  • Uses
    • Eclampsia
    • Torsades
    • Asthma
  • Contraindications
    • Heart block
    • Shock
    • Persistent hypertension
    • Hypocalcaemia
    • Myocardial damage
  • Cautions
    • Renal damage
    • Patients on digoxin
    • Use of CNS depressants or neuromuscular blocking agents
  • Side Effects
    • Hypotension
    • Sedation
    • Confusion
    • Bradycardia
    • Pruritis
    • Arrhythmias
    • Decreased deep tendon reflexes
    • Respiratory depression/paralysis
    • Drowsiness
    • Muscle weakness
    • Complete heart block
  • Dose
    • Torsade de Pointe
      • By intravenous injection over 10–15 minutes
      • Child 1 month–18 years 0.1–0.2 mmol/kg (25–50 mg/kg magnesium sulfate heptahydrate); max. 8 mmol (2 g magnesium sulfate heptahydrate); dose repeated once if necessary
    • Asthma
      • Children over 2 years with severe acute asthma may be helped by intravenous infusion of magnesium sulfate injection 40 mg/kg (max. 2 g) over 20 minutes
Calcium Carbonate
  • Used for: hyperkalaemia, hypocalcaemia, and over-dose of calcium-channel-blocking drugs
  • Dose for urgent calcium correction
    • By slow intravenous injection over 5–10 minutes
    • Neonate 0.11 mmol/kg (0.5 mL/kg of calcium gluconate 10%) as a single dose. [Some units use a dose of 0.46 mmol/kg (2 mL/kg calcium gluconate 10%) for hypocalcaemia in line with US practice]
    • Child 1 month–18 years 0.11 mmol/kg (0.5 mL/kg calcium gluconate 10%), max 4.5 mmol (20 mL calcium gluconate 10%)
Sodium Bicarbonate  
From the PALS algorithm:
"The best treatment for acidaemia in cardiac arrest is a combination of effective chest compression and ventilation (good quality CPR). Administration of sodium bicarbonate generates carbon dioxide, which diffuses rapidly into the cells, exacerbating intracellular acidosis if it is not rapidly cleared via the lungs.
It also has the following detrimental effects:
  • It produces a negative inotropic effect on an ischaemic myocardium.
  • It presents a large, osmotically active, sodium load to an already compromised circulation and brain.
  • It produces a shift to the left in the oxygen dissociation curve further inhibiting release of oxygen to the tissues.
The routine use of sodium bicarbonate in cardiac arrest is not recommended. It may be considered in prolonged arrest, and it has a specific role in hyperkalaemia and the arrhythmias associated with tricyclic antidepressant overdose. "
  • Dose

    • By slow intravenous injection of a strong solution (up to 8.4%), or by continuous intravenous infusion of a weaker solution (usually 1.26%)
    • An amount appropriate to the body base deficit




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