Anaesthesiology: Advanced Life Support Course Flashcards
1
Q
Cardiac arrest
A
- Heart stopped beating —> No CO —> No blood flow to vital organs (***Brain, ***Heart), tissues - Life-threatening emergency - Time is crucial
Management:
- Resuscitation
2
Q
Resuscitation
A
- Maintain adequate **Oxygen + **Blood flow to vital organs
—> Buy time for more definitive therapeutic management - Need to support ABC
—> Airway
—> Breathing
—> Circulation
3
Q
Guidelines on Resuscitation
A
- **American Heart Association guidelines (latest in 2021)
- used by most centres in HK
ILCOR (International Liaison Committee on Resuscitation)
- review latest scientific evidence in 5-yearly cycle
- individual organisations publish guidelines consistent with local needs
4
Q
Basic Life Support (BLS) and Advance Life Support (ALS)
A
Basic Life Support (BLS): - What you can do with just: —> Hands —> Mouth —> AED - Can be done in any settings - Backbone of resuscitation
Advance Life Support (ALS):
- What you can do with more equipment, drugs, health care providers
- Depends on ongoing BLS
5
Q
Main goals of resuscitation
A
- Immediate recognition + activation of emergency response system (call for help)
- High quality CPR
- Chest compression
- Bag valve mask ventilation - Rapid defibrillation
6
Q
***Basic Life Support algorithm
A
- Verify scene safety
- check if scene is safe for provider
- physical threats such as toxic / electrical hazards - Immediate recognition of cardiac arrest
- Check responsiveness
- ***Call for nearby help if person not responsive (叫左先) - Assess breathing + pulse simultaneously
- Pulse check ***<=10s
- Look at chest movement / gasping - Activate emergency response system
- Full activation
- 999 (if outside hospital)
- Hospital arrest team (if in hospital)
- Get AED + emergency equipment (or send someone to do so) - Start CPR (if no pulse + no breathing / only gasping)
- Start with Cardiac compressions —> Airway —> Breathing (**CAB, ∵ initial physiological deficit is lack of blood flow rather than lack of oxygenation)
- Compression : Rescue breath ratio = **30:2
- if 2 rescuers: one do CPR, one do rescue breaths —> 5 cycles (2 mins) —> swap - AED
- Check rhythm —> Shockable rhythm?
—> Shockable: deliver 1 shock, resume CPR immediately for 2 mins until rhythm check by AED, continue until ALS provider take over / patients start to move
—> Non-shockable: resume CPR immediately for 2 mins until rhythm check by AED, continue until ALS provider take over / patients start to move
- NB: NO need to check pulse every 2 mins if AED not available
7
Q
Pulse checking
A
- Check for definite ***carotid pulse
- Can be difficult + inaccurate
- Use ***<=10s
- If in doubt —> Assume patient in arrest —> Activate emergency response system
8
Q
Chest compressions
A
Directly compress the heart
—> ↑ Intrathoracic pressure
—> ↑ Perfusion pressure
—> ↑ Blood flow + O2 to brain & heart
- Heel of hand on centre of chest (lower half of sternum, X ribs, X epigastrium)
- Heel of other hand on top of first hand
- Arms straight + 90o
- ***Rate: 100-120 bpm
- ***Depth: 5-6 cm
- Allow complete recoil of chest after each compression —> avoid leaning on patient in between compressions —> allow heart to fill up
- Minimise frequency + duration of interruptions (esp. unintended reasons)
—> more compressions associated with higher survival rates
—> aim for compression fraction >=60%
—> pause for required care: **Rescue breaths, **Rhythm analysis, ***Defibrillation
Rate too fast:
- associated with inadequate depth (<3 cm)
Compression too deep
- ↑ non-fatal injury (e.g. rib fractures)
9
Q
Airway maneuvers
A
Triple maneuvers:
- Head tilt-Chin lift
- Jaw thrust
- Airway adjuncts (give routinely unless CI)
- Nasopharyngeal
- Oropharyngeal
10
Q
Breathing
A
- Mouth to mouth / Bag mask
- Deliver each rescue breath over ***1 second
- Give sufficient tidal volume to produce ***visible chest rise
- 30:2 —> avoid hyperventilation
11
Q
Automated external defibrillator (AED)
A
- Simple to use —> step by step voice instruction
- AED analyse victim’s heart rhythm (accuracy >90%)
- Gives instructions on whether to deliver shock / continue CPR after rhythm analysis
- Pause CPR (no matter which cycle) whenever AED arrives
—> priority should be given to ***early + rapid defibrillation
12
Q
Defibrillation
A
- ***Ventricular fibrillation: common + treatable initial rhythm in adult witnessed cardiac arrest
- Rapid defibrillation is treatment of choice for **VF + **Pulseless VT
- Highest survival when defibrillation given within ***3-5 mins of collapse
- Connect to AED as soon as available
- Give one shock asap if indicated
- Continue CPR immediately after shock for 2 mins / 5 cycles
- Recheck rhythm every 2 mins (NOT pulse)
13
Q
***Advanced life support algorithm
A
- Start CPR
- give ***highest FiO2 possible (i.e. 100%) (Ambubag + O2 >15L)
- ∵ low blood flow state —> need to maximise O2 content - Attach monitors / defibrillators
- rhythm analysis
- 2 pathways: Shockable vs Non-shockable rhythm (can jump from one to another) - Non-shockable rhythm
- High quality CPR
- Adrenaline 1mg IV / IO (ASAP) every **3-5 mins
- Advanced airway
- Recheck rhythm after **2 min CPR —> decide if shockable or not —> non-shockable —> continue
- Find + treat reversible causes: 5H + 5T - Shockable rhythm
- Immediate defibrillation
- Followed by 2 min CPR
- Rhythm check after 2 min CPR
- Adrenaline after **2nd shock every 3-5 mins
- Advanced airway
- Antiarrhythmic drugs after **3rd shock (Amiodarone / Lignocaine)
- Find + treat reversible causes: 5H + 5T
14
Q
Rhythm in ALS
A
Shockable rhythm:
- VF
- Pulseless VT
Non-shockable rhythm:
- Asystole
- Pulseless electrical activity (PEA)
Can jump from one to another
15
Q
Non-shockable rhythm
A
- Asystole
- no QRS complex - Pulseless electrical activity
- heart rhythm that usually produce a pulse (e.g. narrow complex tachycardia: AF, SVT, Sinus tachycardia etc.)
Management:
- High quality CPR
- Adrenaline 1mg IV / IO (ASAP) every 3-5 mins
- Advanced airway
- Recheck rhythm after 2 min CPR —> decide if shockable or not —> non-shockable —> continue
- Find + treat reversible causes: ***5H + 5T
16
Q
Adrenaline
A
- Parenteral access: IV / IO
—> Drug administration is of secondary importance —> do NOT interrupt / delay chest compression to establish IV / IO access
- ***1mg every ***3-5 mins —> 1ml of 1:1000 —> 10ml of 1:10000 —> paediatrics: 10 mcg/kg —> Higher dose may be indicated if β blocker / CCB overdose
- improve ROSC (return of spontaneous circulation) + survival to hospital discharge
- ***NO advantage of using vasopressin —> removed from guidelines
**MOA:
- α1 + β1 agonist
—> Primary beneficial effects via α1 effects
—> Peripheral vasoconstriction
—> **↑ Aortic diastolic pressure (>40 mmHg)
—> ↑ Coronary + Cerebral perfusion pressure (while ↓ perfusion to other organs (i.e. divert blood from other organs to brain + heart))
—> NOT via β1 effects to ↑ HR / contractility (∵ heart already not functioning)
17
Q
Advanced airway
A
- Supraglottic airway (Laryngeal mask airways)
- Endotracheal tube
- most common form of in-hospital advanced airway
- risks: tube misplacement (e.g. esophagus), ↑ hands off time
- avoid multiple attempts (∵ affect quality of CPR + can inadvertently cause bleeding / edema in upper airway)
- ***NO difference in outcomes between bag mask ventilation / advanced airway devices
- No agreed ideal timing for placement of advanced airway
Compression: Ventilation ratio with advanced airway (X 30:2):
- 1 breath every ***6 seconds (10 breaths per min) (∵ already ensure all air will go into lungs rather than stomach)
- ***Continuous chest compression
- Avoid hyperventilation —> may have worse outcomes
Assessment of tube placement:
- Risks with ETT: esophageal placement, obstruction, dislodgement
- **Continuous CO2 waveform capnography (End-tidal CO2)
—> most reliable method of confirming + monitoring correct ETT placement
—> also monitor CPR quality (EtCO2 during CPR: at most 10 mmHg, consistently **<10 mmHg: poor CPR quality ∵ not returning enough CO2 back out)
—> also detect return of spontaneous circulation (EtCO2 back to ***40 mmHg)
18
Q
5H + 5T
A
H:
- Hypoxia
- Hypovolaemia
- Hydrogen ion (Acidosis)
- Hypo/Hyperkalaemia
- Hypothermia
T:
- Tamponade
- Tension pneumothorax
- Thrombosis, Coronary
- Thrombosis, Pulmonary
- Toxins
- History + P/E (***auscultation to rule out tension pneumothorax)
- Blood tests (POC / Lab): Glucose, Hb (blood loss), Electrolytes (K), Cardiac markers
- Ultrasound: Bedside echocardiogram (pericardial effusion / tamponade)
19
Q
Shockable rhythm
A
- VF
- coarse / fine (can be similar to asystole) - Pulseless VT
Management:
- Immediate Manual defibrillation
- Followed by 2 min CPR
- Rhythm check after 2 min CPR
- Give Adrenaline after ***2nd shock
- Advanced airway
- Antiarrhythmic drugs after ***3rd shock (Amiodarone / Lignocaine)
- Find + treat reversible causes: 5H + 5T
20
Q
Safety measures in electrical therapy
A
- Check for ***indication: it is invasive!
- Ensure good ***contact
- Choose the right ***mode (e.g. Synchronisation in Cardioversion)
- Make sure ***no one touching —> do not defibrillate / cardiovert yourself / any bystander
- Handle the defibrillation paddle with care:
—> Do NOT short circuit (pads must not touch each other + one hand one paddle)
—> Put back to original position when not in use
21
Q
Manual defibrillation
A
- X AED, ∵ manual much faster to analyse rhythm
- delivery of ***large direct current over a very short interval
- ***Unsynchronised manner
Aims:
Depolarise the heart
—> Abolish all prevailing abnormal rhythm
—> Hope that SA node will take over again as pacemaker
Indications:
- VF
- Pulseless VT
- Biphasic: 120-***200J
- Monophasic: 360J
—> Biphasic better than Monophasic —> Higher chance of terminating arrhythmia + Less collateral damage - First shock:
—> manufacturer recommended dose
—> max dose (200J) if unknown - Higher energy for subsequent shock
22
Q
Antiarrhythmic drugs
A
- Amiodarone
- **300mg IV bolus —> then 150mg IV (no guideline on when give 2nd dose)
- max. **450mg - Lignocaine
- Alternative to Amiodarone (e.g. CI to Amiodarone e.g. allergy)
- 1-1.5 mg/kg —> then 0.5-0.75 mg/kg
- Do ***NOT improve long term survival / survival with good neurological outcome
- NO evidence that any antiarrhythmic drug given routinely during human cardiac arrest increases survival to hospital discharge
- Amiodarone: shown to increase ***short-term survival to hospital admission when compared with placebo / lignocaine
23
Q
Amiodarone
A
MOA:
- Affect Na, ***K (affect repolarisation phase), Ca channels
- α + β blocking properties
- Vasodilation + Bradycardia —> can cause hypotension although less pronounced as β blockers / CCB
Indication:
- Recommended for VF + Pulseless VT unresponsive to shock delivery, CPR and a vasopressor
Dose:
- 300mg or 5mg/kg in 20ml dextrose IV / IO bolus
- can be followed by one dose 150mg
24
Q
Interventions not routinely recommended
A
- NaHCO3
- Ca
- IV fluids
- Precordial thump (rarely, for termination of witnessed monitored unstable VT when defibrillator not available)
25
Q
NaHCO3
A
Reverse acidosis
- multiple unwanted effects
1. Compromise CPP (Coronary perfusion pressure) by reducing SVR
2. ***Extracellular alkalosis - shift O2 dissociation curve (ODC) to **left —> inhibit O2 release
3. **HyperNa, **Hyperosmolarity
4. Excess CO2 production —> **Paradoxical intracellular acidosis
5. May inactivate simultaneously administered catecholamine
Can be beneficial in special circumstances:
1. Pre-existing acidosis
2. HyperK
3. Tricyclic antidepressant overdose
—> esp. if these are underlying causes of cardiac arrest (e.g. ESRF)
26
Q
Calcium
A
Inotrope
- routine use not recommended
- not supported by clinical trials
- acceptable, probably helpful in HyperK, HypoCa, Drug overdose with CCB
- can exacerbate cell injury (toxic to myocyte)
27
Q
Mechanical chest compression device
A
- No benefit compared with manual chest compressions
—> Manual compressions: Standard of care - Free up people to do other stuff
- Alternative in challenging situations e.g. dangerous environment for provider, angiography suite
28
Q
Extracorporeal CPR (ECPR)
A
- Pump with oxygenator to oxygenate blood + remove waste from patient
Indication:
- If expected cardiac arrest will be prolonged but still reversible
—> buy more time
- Not routinely used
- Highly trained team, specialised team (ICU physicians)
- Cannulation of large veins + artery —> venoarterial extracorporeal circulation + oxygenation
- Select patients: suspected etiology potentially reversible during limited period of mechanical support (e.g. LA toxicity)
- Setting: ***need rapidly implemented, need quickly prime machine + heparin
- Still can only be used for short period of time
29
Q
Return of Spontaneous Circulation (ROSC)
A
Return of:
- Pulse
- BP
- Breathing
If NO signs of ROSC
—> continue CPR, Adrenaline
—> consider appropriateness for continued resuscitation
If ROSC —> Post-cardiac arrest care
30
Q
Post-cardiac arrest care
A
Aim:
- Brain + Cardiac status major determinant of survival
- ***Optimise cardiopulmonary function + vital organ perfusion after ROSC
- Transport / transfer to an appropriate hospital / ICU / CCU
- have better monitoring + intensive support - Identify + treat ACS and other reversible causes (e.g. ACS)
- Control temperature to optimise ***neurologic recovery
- Anticipate, treat, prevent multiple organ dysfunction
- ***Prevent going back to cardiac arrest again
2 Phases:
- Initial stabilisation (ABC)
- Continued management + additional emergent activities
31
Q
Post-cardiac arrest care: 1. Initial stabilisation (ABC)
A
- Airway
- Early placement of ***ET tube (Definitive airway ∵ still breathing poorly / unconscious —> still need ventilatory support) - Manage respiratory
parameters
- Titrate FiO2 to achieve SaO2 **92-98% (X 100% (unlike during cardiac arrest care): oxygen free radicals released —> toxic to brain)
- **Normocarbia: PaCO2: ***35-45 mmHg (too low: cerebral blood vessels constricted —> inadequate cerebral perfusion; too high: cerebral edema)
- RR: 10 breaths / min - Manage haemodynamic parameter
- ***Avoid Hypotension
- SBP >90 mmHg
- MAP >65 mmHg
—> By Inotropes (Adrenaline / NE ∵ some degree of myocardial ischaemia during resuscitation + support BP), Fluids (fluid overload if no inotropes given at the same time) - 12-lead ECG
- to rule out ACS - Actively treat cause of cardiac arrest
- Review 5Hs + 5Ts —> Take blood
32
Q
Post-cardiac arrest care: 2. Continued management + additional emergent activities
A
- Consider for emergent ***cardiac intervention if:
- STEMI present
- Unstable cardiogenic shock
- Mechanical circulatory support required - If Comatose
- **Targeted temperature management (TTM)
—> Avoid **hyperthermia to protect brain (↓ workload for brain cells)
—> May improve neurological outcome
—> For ALL comatose patients with ROSC
—> Constant temp between **32-36oC for **24 hours
- Brain CT
- EEG monitoring —> for ***seizures
- Other critical care management - If Awake
- Other critical care management - Evaluate + Treat rapidly reversible etiologies, involve expert consultation for continued management
33
Q
Summary
A
- Cardiac arrest: No blood flow to tissue (esp. Brain + Heart)
- Time is critical
- Immediate recognition of cardiac arrest + activation of emergency response
- Effective CPR
- Early defibrillation for shockable rhythm
