Emergency Medicine - BLS, ACLS Flashcards
Outline the Basic Life Support algorithm for adult cardiac arrest
- Check environment safety (e.g. for physical hazards)
- Immediate recognition and activation of emergency response system:
→ Call 999 if outside hospital
→ Call hospital arrest team if inside hospital
→ Should retrieve AED by 2nd rescuer (if witnessed) or by lone rescuer (if alone) - Diagnose cardiac arrest within 10s
→ Unresponsive
→ No breathing or only gasping
→ No definite carotid pulse within 10s - Start Basic Life Support
→ Recovery position if normal breathing
→ Ventilation alone if no breathing but normal pulse
→ Compression followed by ventilation at 30:2 (i.e. CAB approach) if no breathing + no pulse - Early defibrillation (if indicated)
- Early advanced life support
Define high quality CPR
Chest compression:
□ Push fast: 100-120/min for both adults and kids
□ Push hard: 5-6cm
□ Allow complete recoil: ↓intrathoracic pressure to allow ↑VR
□ Avoid interruption: only acceptable for (1) rhythm analysis (2) rescue breaths (3) defibrillation
□ Switching of compressor: switching of provider every 2min to ensure chest compression quality
Ventilation:
□ Options:
→ Mouth-to-mouth ventilation
→ Mouth-to-mask ventilation
→ Self-inflating bag via bag-valve-mask or advanced airway
□ Rate: 30:2 unless advanced airway (then 10 breaths/min), Hyperventilation should be avoided
Treatment for shockable rhythm
- Shockable rhythms
- Energies/ types
- Timing for successive shocks
- Treatment
Shockable rhythms
→ VF: totally uncoordinated contraction of ventricles
→ Pulseless VT: LV rate too fast to pump blood effectively
Energy for cardiac defibrillation:
- 360J for monophasic; 120-200 for Biphasic
- Increase energy for subsequent shocks
Treatment timeline:
* Connect AED within 3-5min
* Give one shock ASAP
* Continue CPR immediately after shock for 2 min (or 5 cycles)
* Recheck rhythm every 2 minutes (not pulse)
* Secure IV/IO access without interrupting chest compression
* Give IV adrenaline 1mg every 3-5 minutes after 2nd shock
* Give IV amiodarone 300mg after 3rd shock, 150mg after 5th shock
* Consider IV lidocaine 1-1.5mg/kg if amiodarone unavailable
* Consider advanced airway
* Find reversible causes (5H 5T)
Define shockable and non-shockable rhythms
Shockable rhythms:
→ VF: totally uncoordinated contraction of ventricles
→ Pulseless VT: LV rate too fast to pump blood effectively
Non-shockable rhythms: more common in hospital settings
→ Asystole: flatline on ECG without any QRS complexes
→ Pulseless electrical activity (PEA): no pulse despite organized electrical activity (degenerates into asystole soon)
Airway protection and Advanced airway options for cardiac arrest
Airway protection
* Head tilt-chin lift, Jaw thrust
* Airway adjuncts: nasopharyngeal, oropharyngeal airway
* Advanced airway: Endotracheal intubation or supraglottic advanced airway
Breathing:
* Mouth to mouth or bag-valve-mask
* Deliver each rescue breath over 1 second
* Give a sufficient tidal volume to produce visible chest rise
* 30:2 (1 breath every 6 seconds (10 breaths per min)
* Avoid hyperventilation, keep continuous chest compressions
Assess return of spontaneous circulation
□ Breathing returns
□ Pulse with BP returns (in NIBP or arterial waveform)
□ Sudden rise in etCO2 to ~40mmHg
□ Should check and support vitals including SpO2 and BP
Define reversible causes of cardiac arrest
Advanced life support flowchart
Basic: Call for help, activate ERS
- Start CPR, give highest FiO2.
- Attach monitors or defibrillator: Separate into shockable and unshockable rhythm pathways
- Defibrillate and CPR, check pulse and rhythm every 2 minutes
- Add drug therapy if refractory
- Consider advanced airway
- Find reversible underlying cause: 5H and 5T
- Continue CPR for one more cycle after ROSC
Treatment for Non-shockable rhythm
Treatment:
* Perform high quality CPR ASAP
* Check rhythm/ pulse every 2 mintues
* Advanced airway
* Parenteral Access (IV/IO) w/o interrupting chest compression; try endotracheal or interosseous route if needed
Drug therapy:
* Adrenaline 1mg IV every 3-5 minutes
* Amiodarone 300mg for arrhythmia
* Lignocaine or MgSO4 if necessary
Adrenaline for non-shockable rhythm
MoA
Dosage
Timing
Effect
Mechanism:
α effect → constricts peripheral circulation → ↑↑aortic diastolic pressure (>40mmHg) → ↑coronary and cerebral perfusion pressure
Timing: ASAP if non-shockable; or after 2nd shock (but usu given asap) if shockable
Dose: 1mg (adults), 10μg/kg (paeds), higher dose if β-blocker or CCB overdose
Effect: improve ROSC rate but no difference in survival to discharge
Cardiac arrest
Causes
Definition
Cardiac arrest defined as sudden and complete loss of CO (life-threatening emergency!)
Causes:
□ Coronary artery disease (85%): myocardial ischaemia, AMI, prior MI with myocardial scarring
□ Structural heart disease (10%): AS, HCM, DCM, ARVD, congenital HD
□ Others (5%): LQTS, Brugada syndrome, WPWS, drug-induced TdP, severe electrolyte imbalance
Difference between children/ infant vs adult CPR
Children/ infants:
- If witnessed collapse, proceed with same BLS flow as adults
- If unwitnessed collapse and lone rescurer, give 2 minutes of CPR FIRST (c.f. leave to activate emergency response system and get AED before CPR for adults), then leave for ERS & AED, then return for CPR
Children/ infant:
- Compression-ventilation ratio without advanced airway: 30:2 if lone rescurer (same as adult), 15:2 if 2 or more rescurer
Children/infant:
- Chest compression depth: 1/3 AP diameter of chest, 5cm for children and 4cm for infants
- 2 fingers on chest or 2 thumb encircling chest for infant
Adjunctive treatments to CPR
Monitoring metrics
Airway and breathing management during CPR:
- Triple maneuver
- BVM for ventilation
- Airway adjuncts with BVM if possible
- Advanced airways (LMA, ETT) if refractory
- IPPV for prolonged ventilation
- High flow 100% O2 if possible
Continuous monitoring: capnography, arterial BP and SvO2
Ultrasound: help assess myocardial contractility and identify potentially treatable causes of cardiac arrest
Amiodarone for ACLS
MoA
Dose
Timing
Effect
Mechanism: affects Na, K, Ca channels with α- + β-blocking properties
Timing: usually after 3rd shock in VF or pulseless VT, give again after 5th shock if refractory
Dose: 300mg or 5mgkg in 20mL dextrose IV/IO bolus followed by one dose 150mg (5th shock)
Effect: termination of arrhythmia, ↓admission but does not improve long-term survival or survival with good neurological outcome
Alternatives: Lignocaine or MgSO4
List all drug options for ACLS
Indication and use
Adrenaline: ASAP for non-shockable, after 2nd shock if shockable
Amiodarone: after 3rd and 5th shock if shockable
Lignocaine: anti-arrhythmic alternative to amiodarone
Magnesium Sulphate: for shockable rhythm a/w Torsades de Pointes only
Tachyarrhythmia treatment
Evaluating rhythm by 12-lead ECG
- Narrow complex, regular → likely SVTs
- Narrow complex, irregular → likely AF
- Broad complex, regular → likely monomorphic VT
- Broad complex, irregular → likely polymorphic VT (or VF if pulseless)
Only Haemodynamically unstable patients need electrical cardioversion
Medical therapy:
□ AVN blocker for narrow complex tachycardia (for rate control): Vagal maneouvers and IV adenosine for AVRT/AVNRT
□ Antiarrhythmics for wide complex tachycardia (for rhythm control) → IV procainamide, amiodarone or sotalol for monomorphic VT
Cardioversion:
- Indications: unstable tachycarrhythmia with a pulse - Eg. fast AF, fast AFlu, pSVT, VT with pulse
- Requires consent with sedation (midazolam) + analgesics (morphine) as it is painful
- Energy: 50-100J (for narrow regular), 120-200J (for narrow irregular), 100J (for wide regular)
- Absolute C/I: sinus tachycardia (only absolute C/I)
Bradyarrhythmia treatment
Evaluate rhythm by 12-lead ECG
□ If haemodynamically stable, then can monitor and observe
□ If haemodynamically unstable, then should give atropine followed by pacing
Medical therapy: IV atropine 0.5mg every 3-5min: 1st line
Alternative drugs: if a/w hypotension or after atropine fails
→ Dopamine infusion
→ Adrenaline infusion
Cardiac pacing: bradycardia with unstable haemodynamic status
→ Transcutaneous pacing (TCP): 1st-line in emergency setting
→ Transvenous: less tissue damage, 2nd-line
→ Sedate (midazolam) the patient + give analgesics (morphine) (VERY PAINFUL!)
→ Adjust current until threshold to obtain mechanical capture of heart: start at 70ppm, 30mA
