Managing cardiac arrest Flashcards
what is a cardiac arrest?
effective cessation of the heart
- no circulation & no oxygen delivered
how do you recognise somebody is having a cardiac arrest?
1) unresponsive
2) not breathing normally
3) no pulse
why is the majority of cardiac rhythm shockable (i.e. able to be defibrillated?
- as presenting rhythm in most cases is VF/VT
= majority is potentially reversible
what 2 things commonly precede cardiac arrest?
- hypotension
- hypoxia
when should defibrillation be given, if appropriate?
= within 3 minutes
what are most problems of cardiac arrest caused by?
1) airway
2) breathing
3) circulation
= oxygen delivery problems
how can you improve SaO2 oxygen delivery factors?
1) SaO2
= clear airway
how can you improve [Hb= for oxygen deliver?
= transfusion trigger, treat anaemia
how can you alter heart rate for oxygen delivery?
= atropine or B-stimulant (e.g. ephedrine) for bradycardia, pace
how can you alter stroke volume to improve oxygen delivery?
1) preload = IV fluids, raise legs
2) afterload
= excess afterload (HBP) use vasodilators
= reduce after load (e.g. septic shock) use vasoconstrictors
3) contractility = treat cause
what other factors affect oxygen delivery?
= BP
how would you manage a cardiac arrest patient?
ABCDE
how can you check for SaO2 and [Hb] levels?
SaO2
= pulse oximetry on finger
= arterial blood fas (GOLD STANDARD)
[Hb]
= part of full blood count
- bedside (e.g. hemocue)
how would you check heart rate?
- pulse
- pulse oximetry
- ECG monitor with sound
- arterial BP monitor
how would you calculate B{?
BP = CO x TPR
what are 4 causes of obstruction which causes AIRWAY problems?
1) CNS depression = tongue
2) lumen blocker = blood, vomit, foreign body
3) swelling = trauma, infection, inflammation
4) muscle = laryngospasm., bronchospasm
how would you recognise airway obstruction (SpO2)?
- talking
- difficult breathing, distressed, choking
- shortness of breath
- noisy breathing = stridor, wheeze, gurgling
- see saw respiratory pattern using accessory muscles
how would you treat airway obstruction (SpO2)?
- airway opening
e. g. head tilt, chin lift, jaw thrust, suction - simple adjuncts
- advanced techniques
e. g. LMA, tracheal tube - oxygen (increase FiO2)
what are causes of BREATHING problems (SpO2)?
1) airway problems
2) decreased respirator drive
- CNS depression
3) decreased respiratory effort
- muscle weakness, nerve damage, restrictive chest defect, pain from fractured ribs.
4) lung disorders
- pneumothorax, haemothorax, infection, acute exacerbation COPD, asthma, PE, ARDS
how would you recognise breathing problems (SpO2)?
1) look - respiratory distress, accessory muscles, cyanosis, respiratory rate, chest deformity, consciousness level
2) listen - noisy breathing, breath sounds
3) feel - expansion, percussion, tracheal position
how would you treat breathing problems (SpO2)?
- oxygen
- airway
- treat underlying cause to improve breathing
e. g. drain pneumothorax - support breathing
e. g. ventilate with bag mask
what are primary and secondary causes of circulatory problems ([Hb]/CO)?
Primary
- Acute coronary syndromes
- Dysrhythmias
- Hypertensive heart disease
- Valve disease
- Drugs
- Hereditary cardiac diseases
- Electrolyte / acid base
- abnormalities
- Electrocution
Secondary Asphyxia
- Hypoxaemia
- Blood loss
- Hypothermia
- Septic shock
how would you recognise circulatory problems?
[Hb], CO = HR x SV
- general exam = distres, palor
- indications of organ perfusion
= chest pain, mental state, urine output - blood pressure
- pulse, tachycardia, bradycardia
- peripheral perfusion = capillary refit time
- bleeding, fluid losses, JVP, CVP
how do you treat circulatory problems?
1) ensure airway, breathing O2
2) IV/IO access, take bloods
3) treat cause
- fluid challenge
- inotropes/vasopressors
- oxygen, aspiring, nitrates, morphine for ACS
4) haemodynamic monitoring
how do you recognise disability?
Treatment - ABC = treat underlying cause = blood glucose - if < 3mmol-1 give glucose = consider lateral (recovery) position = check drug chart
what heart rhythm is shockable and non-shockable?
SHOCKABLE
= VF
= pulseless VT
NON-SHOCKABLE
= asystole
= pulseless electrical activity (PEA)
why is ventricular fibrillation shockable, whats its ECG appearance?
- bizarre irregular waveform
- no recognisable QRS complex
- random frequency and ampltitude
- uncoordinated electrical activity
- coarse/fine
describe ventricular tachycardia, whats its ECG appearance?
Monomorphic VT
- broad complex rhythm
- rapid rate
- constant QRS morphology
Polymorphic VT
- torsade de pointes
what is pre-cordial thump?
= only use if defibrillator is not immediately available AND monitored VF/VT cardiac arrest
what is a defibrillator?
use of electrical current to “reset” heart electrical rhythm with hope that regular rhythm will recur.
why are pads used in defibrillation?
to minimise interruptions
After delivery of shock, then immediate CPR, check for 2 minutes. If VF/VT persists what would you do?
1) deliver 2nd shock
2) CPR for 2min
3) deliver 3rd shock
4) CPR if VF/VT persists
Adrenaline 1mg IV
when should adrenaline and amiodarone be given?
ADRENALINE
- after 3rd shock then after alternate shocks (every 3-5mins)
AMIODARONE
- after 3rd shock
why is asystole non shockable, describe its ECG appearance?
= effectively flat line
- absent ventricular QRS activity
- atrial activity (P wave) may persist
- rarely a straight line trace, its a wave line
how should you treat asystole?
- adrenaline 1mg IV soon as
- every 3-5mins thereafter (every 2 CPR cycles)
why are pulseless electrical activity non-shockable? describe its ECG appearance?
- ECG normally associated with an output
how would you treat pulseless electrical activity?
- exclude/treat reversible causes
- adrenaline 1mg IV as soon as possible
- every 3-5mins thereafter, every 2 cycles
what dose of adrenaline and amiodarone should be given?
and what does adrenaline act as?
Adrenaline 1mg
Amiodarone 300mg
- alpha vasoconstrictors
- B inotropic
what are the 4Hs and 4Ts?
= potential reversible causes
H’s
- hypoxia
- hypovolaemia
- hypo/hyperkalaemia/metabolic
- hypothermia
T's = thrombosis - coronary/pulmonary = tension pneumothroax = tamponade - cardiac = toxins
how would you treat hypoxia?
= airway and ventilation
1) secure airway
- tracheal tube
- suprglottic airway device, e.g. LMA/iGel
2) once airway is secured, don’t interrupt chest compressions for ventilation
3) avoid hyperventilation
what are advantages & disadvantages of mouth to mask ventilation?
ADVANTAGES;
- avoids direct person to person contact
- decreases potential for cross infection
- allows oxygen enrichment
LIMITATIONS:
- maintenance of airtight seal
- gastric inflation
advantages and disadvantages of self-inflating bag?
ADVANTGES;
- avoids direct person to person contact
- all O2 supplementation = up to 85%
- can be used with facemark, LMA, combitube, tracheal tube
DISADVANTAGES - when used with a facemark; = risk of inadequate ventilation = risk of gastric inflation = need 2 persons for optimal use
advantages of disadvantages of laryngeal mask airway (LMA)?
ADVANTAGES ;
- Rapidly and easily inserted
- Variety of sizes
- More efficient ventilation than facemask
- Avoids the need for laryngoscopy
DISADVANTAGES
- No absolute guarantee against aspiration
- Not suitable if very high inflation pressures needed
- Unable to aspirate airway
what are problems of insertion of tracheal tube?
- incorrect placement
- delays CPR or defibrillator
how would you treat hypovolaemia?
IV fluids
how would you treat hypo/hyperkalaemia/metabolic?
- correct accordingto U&Es/blood gases
how would you treat thrombosis, tension pneumothorax, cardiac tamponade and toxins?
thrombosis
= thrombolysis
tension pneumothorax
= needle thoracentesis
cardiac tamponade
= needle cardiocentesis
toxins;
= specific treatment/antidote
when should you stop CPR?
= when return of spontaneous circulation (ROSC)
- when seems useless, time, diagnosis, pre-arrest conditions or DNR/DNAR
what are 4 factors of post-cardiac arrest syndrome?
1) post cardiac arrest brain injury
2) post cardiac arrest Myocardial dysfunction
3) systemic ischaemia / re-perfussion response
4) persistant precipitating pathology
what should be done immediately after post resuscitation?
1) 12 lead ECG
2) reliable IV access
3) intra-arterial BP monitor
4) target SBP > 100mmHg
5) fluid (crystalloid) normovolaemia
6) consider inotrope/vasopressor
in unconscious adults with risk of spontaneous circulation after arrest be temperature managed to?
32-36degrees.
