Peri-arrest arrhythmias Flashcards
A-E assessment
Airway/breathing.
- Assess airway and breathing status
- Monitor SpO2 and RR
- Give oxygen immediately to hypoxaemic patients (<94%) and adjust delivery according to oxygen saturations
- ABG
Circulation.
- Assess status (colour, CRT, pulses, BP, JVP, etc.)
- Monitor HR and BP
- Gain IV access
- Venous gas: immediate Hb, U+Es, pH, glucose
- Bloods sent to lab (FBC, U+Es, LFTs, clotting, calcium, CULTURES, glucose, ?troponins, ?group/save, ?TFTs)
- IV fluids if indicated
- ECG - assess rhythm, dictates treatment
- Correct electrolyte abnormalities (eg. K+, Mg2+, Ca2+, glucose)
- Note the presence or absence of ‘adverse features’
Assessing severity.
a) ‘Adverse features’ that indicate whether patient is stable or unstable (risk of death)
b) What must you check? - absence dictates switching to ALS algorithm
a) - Shock – hypotension (systolic BP <90), pallor, sweating, cold, clammy extremities, confusion or reduced GCS
- Syncope – transient LOC
- Myocardial ischaemia – typical ischaemic chest pain and/or typical ECG changes
- Heart failure – pulmonary oedema and/or raised JVP, +/- peripheral oedema and hepatomegaly
b) Pulse
4 basic management options for peri-arrest arrhythmias
- depends on nature of arrhythmia and whether patient is stable or unstable
- No treatment
- Simple manouevres (e.g. vagal stimulation)
- Drugs:
- adrenaline
- atropine
amiodarone - Electrical
- cardioversion (tachy)
- transcutaneous pacing (brady)
Tachyarrhythmia: management algorithm.
a) Initial management
b) Unstable (presence of ‘adverse features’)
c) If stable, must determine what 2 things to classify the rhythm?
a) - A-E
- Note presence of ‘adverse features’ (stable/unstable)
- Treat reversible causes (eg. electrolytes)
b) - Synchronised DC cardioversion up to 3 attempts*
- Then IV amiodarone 300 mg over 15 - 20 mins
- Repeat shock
- Then IV amiodarone 900 mg over 24 hours
- Conscious patients require sedation or GA
- synchronised DC is synchronised with the QRS, where defibrillation occurs randomly in the cardiac cycle
c) - Broad-complex (QRS > 120 ms) or narrow-complex?
- For each, is the rhythm regular or irregular?
Narrow-complex tachyarrhythmias: management*
a) If regular - 3 most likely causes and management
b) If irregular - likely cause and management
- If stable - if presence of adverse features, revert to management of unstable tachyarrhythmia
a) Sinus tachycardia (NOT an arrhythmia):
- Treat underlying cause (eg. infection, blood loss, anaemia ,etc.)
- Do NOT give cardioversion or antiarrhythmic drugs
SVT (AVNRT):
- Vagal manoeuvres
- Adenosine - 6 mg rapid IV bolus; if no effect give 12 mg; if no effect again give further 12 mg
- Monitor/record ECG continuously
Atrial flutter (2:1 AV block = HR ~ 150 bpm) - Beta-blockade
b) AF:
- If acute (< 48h) - consider electrical or chemical cardioversion
- Control rate with beta-blocker or diltiazem
- If in heart failure, consider digoxin or amiodarone
- Assess VTE risk and anticoagulate if necessary
Broad-complex tacharrhythmias: management*
a) If irregular - likely cause and management
b) If regular - 2 most likely causes and management
- If stable - if presence of adverse features, revert to management of unstable tachyarrhythmia
a) AF with bundle branch block:
- Treat as per AF (BBs or CCB; digoxin or amiodaron in CCF)
b) - Monomorphic VT*: IV amiodarone 300 mg over 20 - 60 mins, then 900 mg over 24 hours
- SVT with bundle branch block: vagal manouevres, IV adenosine, beta-blockade, etc.
- note: polymorphic VT (eg. Torsades) is highly likely to present with adverse features, requiring cardioversion
Torsades de Pointes.
a) Usual cause
b) ECG features
c) Management
d) Drug to avoid and why?
a) Ischaemia, QT prolongation (macrolides, TCAs, antipsychotics, hypoK+, hypoMg+, hypoCa2+, hypothermia, channelopathies)
b) - Broad-complex tachycardia
- Twisting of QRS complexes around the isoelectric line
- QT prolongation
c) - Stop all drugs known to prolong the QT interval
- Correct electrolyte abnormalities, especially low K+
- Give magnesium sulfate 2 g IV over 10 min (= 8 mmol, 4 mL of 50% magnesium sulfate)
- If adverse unstable (likely), immediate synchronised DC cardioversion under sedation or GA
- If the patient becomes pulseless, attempt defibrillation immediately (ALS algorithm)
d) Amiodarone - prolongs the QT (class III antiarrhythmic)
Administering adenosine.
- Use a relatively large cannula and large vein (e.g. ACF)
- Warn the patient that they will feel unwell and probably experience chest discomfort for a few seconds after the injection.
- Initial: 6 mg as a rapid IV bolus.
- Record an ECG during the injection.
- If no response, give 12 mg, then again if necessary
AF with WPW.
a) Drugs to avoid and why?
b) Management
a) AV nodal blockers: adenosine, BBs, CCBs (diltiazem, verapamil) digoxin
b) Amiodarone
Bradycardia
a) Define bradycardia
b) Causes of bradycardia
a) HR < 60
b) - Physiological (e.g. during sleep, in athletes)
- Cardiac (e.g. AV block or SA node disease)
- Non-cardiac (e.g. vasovagal, hypothermia, hypothyroidism, hyperkalaemia)
- Drugs (e.g. beta-blockade, diltiazem, digoxin, amiodarone) in therapeutic use or overdose
Bradyarrhythmias.
a) Initial assessment
b) If any adverse features (unstable) - initial management
c) If stable, who to treat (risks of asystole)
d) Further management
a) A-E: monitor SpO2, oxygen if hypoxic, monitor HR and BP, ECG, IV access
- Look for any adverse features (shock, syncope, ischaemia, heart failure)
- Treat any reversible causes (eg. electrolytes, drugs)
b) IV atropine* 500 mcg
* Do not give in ischaemia (tachycardia may worsen infarct), or patients with heart transplant (denervated, may cause AV block or sinus arrest)
c) - Recent asystole, Mobitz type II / complete heart block, ventricular pause > 3 s
(if none present, continue observation)
d) - IV atropine 500 mcg can be given every 3 - 5 mins up to a maximum of 3 mg (6 doses)
- If these do not work, transcutaneous pacing is next best option
- If tc-Pacing not immediately available, consider other drugs (eg. isoprenaline, adrenaline, dopamine, glycopyrronium, theophylline)
- In extreme cases, may try fist pacing
- Transvenous pacing may be useful in Mobitz type II or complete heart block
