6. ALS algorithm

Question 1

2 main groups of heart rhythms associated with cardiac arrest?

Answer 1

shockable (VF/ pVT)
non-shockable (PEA/ asystole)

Question 2

name the interventions that improve survival after cardiac arrest

Answer 2

1) prompt and effective bystander CPR
2) uninterrupted, high quality CPR
3) early defibrillation for VF/ pVT

(drugs and advanced airways are of secondary importance to these)

Question 3

the first monitored rhythm is shockable/ non-shockable in approx 20% of cardiac arrests

Answer 3

shockable (VF/ pVT)

Question 4

placement of defib pads?

Answer 4

below the right clavicle
V6 position, midaxillary line

Question 5

next step after confirming the rhythm is VF/ pVT?

Answer 5

resume chest compression immediately, warn all other than the chest compressor to ‘stand clear’ and remove any oxygen devices

select the appropriate energy on the defibrillator and press charge

Question 6

what energy setting should you choose for the first shock?

Answer 6

120 to 150 J (the same or higher for subsequent shocks)

Question 7

T/F: after delivering the shock, continue to pause compressions to feel for a pulse

Answer 7

false - immediately restart CPR in 30:2 ratio starting with compressions

Question 8

how long between rhythm checks?

Answer 8

2 minutes

Question 9

when to give drugs and what drugs to give

Answer 9

after 3rd shock,
give intravenous 1mg 1:10,000 adrenaline and 300mg amiodarone at the next rhythm check (in 2 mins)

Question 10

how often and how much adrenaline should be given?

Answer 10

1mg of 1:10,000

after 3rd shock then every alternate shock thereafter (3-5 mins approx)

Question 11

T/F: the time between ROSC and return of a palpable pulse is typically < few seconds

Answer 11

false - can take up to 2 minutes
do not delay restarting chest compressions in order to check pulse

Question 12

T/F: if a perfusing rhythm has been restored, giving chest compressions increases the chance of VF recurring

Answer 12

false!

Question 13

how often and how much amiodarone should be given?

Answer 13

after 3rd shock - 300mg IV
if VF/ pVT persists or recurs, a further dose may be given after a total of 5 defibrillation attempts - 150mg IV

Question 14

alternative if amiodarone is not available?

Answer 14

lidocaine 1mg/kg
do not give if amiodarone has been given already

Question 15

what can be done to the pads in refractory VF/ pVT?

Answer 15

consider changing pad position e.g. to anterior-posterior

Question 16

T/F: if a rhythm compatible with a pulse is seen during a 2 min period of CPR, stop to palpate the pulse

Answer 16

false - unless the pt shows signs of life suggesting ROSC

Question 17

Are precordial thumps routinely recommended?

Answer 17

no - very low success rate for cardioversion of a shockable rhythm

only use if can be used without delay whilst awaiting the arrival of a defibrillator in a monitored VF/pVT arrest

Question 18

how to carry out a precordial thump?

Answer 18

deliver sharp impact to lower half of sternum using ulnar edge of tightly clenched first from height of 20cmT

Question 19

T/F: there is a very high chance of ROSC when defibrillation occurs immediately after the onset of VF/ pVT

Answer 19

true- hence why 3 stacked shocks recommended when these arrests occur in monitored environments

Question 20

If the initial 3 stacked shocks method is used (ie in a monitored environment), when should the first dose of ADRENALINE be administered?

Answer 20

after 2 more subsequent shocks (the 3 initial shocks are treated as the first shock in the ALS algorithm)

Question 21

If the initial 3 stacked shocks method is used (ie in a monitored environment), when should the first dose of AMIODARONE be administered?

Answer 21

during the 2 min of CPR after the 3 stacked-shock attempts

Question 22

PEA is cardiac arrest in the present of electrical activity (other than ___ ___) that would normally be associated with a palpable pulse

Answer 22

ventricular tachyarrhythmia

Question 23

Whenever a diagnosis of systole is made, check the ECG carefully for the presence of P waves - why?

Answer 23

because in this situation, ventricular standstill may be treated effectively by cardiac pacing

Question 24

treatment algorithm for PEA and asystole?

Answer 24

start CPR 30:2
give adrenaline 1mg IV soon as IV access achieved
recheck rhythm after 2 mins: if electrical activity compatible with a pulse is seen, check for pulse/ signs of life
if none, continue CPR giving further adrenaline every alternate 2 minute cycle
change to shockable algorithm if VF/ pVT seen at a rhythm check

Question 25

T/F: if VF is seen on the monitor during the break for ventilations (rather than at the end of the 2 min cycle), administer the shock then before waiting for the end of the 2 min cycle

Answer 25

False - still wait until the end of the 2 min cycle

Question 26

Airway equipment to be used in the absence of someone skilled in tracheal intubation?

Answer 26

bag-mask, or preferably, a supraglottic airway (e.g. i-gel)

Question 27

T/F: once a supraglottic airway has been inserted, you can attempt to deliver continuous chest compressions, uninterrupted during ventilation

Answer 27

True - you can ventilate the lungs at 10 breaths a minute (monitor to check for excessive gas leakage that may cause inadequate ventilation - if so interrupt compression to enable ventilation)

Question 28

T/F: studies have shown tracheal intubation increases survival after cardiac arrest

Answer 28

false - nil evidence to show it increases survival compared with BMV or use of an SGA

furthermore long pauses in chest compression or incorrect placement of the tube is common in arrest if intubation is attempted by unskilled personnel

Question 29

T/F: you should avoid stopping chest compressions during laryngoscopy and intubation if possible

Answer 29

true - if necessary there can be a brief pause as the tube is passed between the vocal cords but that should not exceed 5s

Question 30

after intubation, how should correct tube position be confirmed?

Answer 30

with waveform capnography

Question 31

a pulse that is felt in the femoral triangle during CPR can indicate ___ rather than arterial blood flow

Answer 31

venous

Question 32

T/F: during cardiac arrest, ABGs are of limited value

Answer 32

true - may be misleading and bear little relationship to the tissue acid-base state (central venous blood better)

Question 33

normal PaCO2? (concentration of CO2 in arterial blood)

Answer 33

5.3

Question 34

the partial pressure of CO2 at the end of an exhaled breath is called what?

Answer 34

end-tidal CO2

Question 35

what is end-tidal CO2 a reflection of?

Answer 35

cardiac output, pulmonary blood flow and the ventilation minute volume

Question 36

name some of the roles of waveform capnography during CPR

Answer 36

• ensure tracheal tube placement
• monitoring ventilation rate
• monitoring chest compression quality
• identifying ROSC
• prognostication

Question 37

on waveform capnography what does
1) the first upstroke bit
2) the plateau
3) the last downstroke bit
represent?

Answer 37

1) start of expiration
2) alveolar plateau as gas from alveoli take part in gas exchange
3) the end of expiration

Question 38

what is the normal end-tidal CO2 in health patients?

Answer 38

4.8

Question 39

rate of ventilation during CPR? (once tracheal tube/ secure SGA has been secured)

Answer 39

10/ min

Question 40

T/F: if ROSC is suspected during CPR, withhold adrenaline

Answer 40

true - then give if cardiac arrest is confirmed at the next rhythm check

Question 41

T/F: failure to achieve an end-tidal CO2 > 1.33 after 20 mins CPR should indicate that efforts should be stopped

Answer 41

false - is a poor prognostic indicator but shouldn’t be used on its own to stop CPR efforts

Question 42

3 main insertion sites for IO?

Answer 42

proximal humerus, proximal tibia and distal tibia

Question 43

contraindications to IO?

Answer 43

trauma, infection, a prosthesis at the target sitec, or recent IO access in the past 48 hours in the same limb

Question 44

complications of IO?

Answer 44

extravasation into the soft tissues, dislodgement of the needle, compartment syndrome due to extravasation, fracture/ chipping of the bone, pain related to the infusion or drugs/ fluid, fat emboli, infection/ osteomyelitis

Question 45

reversible causes of cardiac arrest?

Answer 45

hypoxia
hypovolaemia
hyper/hypo-kalaemia/ hypoglycaemia/ calcaemia / metabolic
hypothermia

thrombosis (coronary/ pulmonary)
tension pneumothorax
tamponade (cardiac)
toxins

Question 46

When might IV calcium chloride be given in cardiac arrest?

Answer 46

hyperkalaemia
hypocalcaemia
calclium channel-blocker overdose

Question 47

commonest cause of thromboembolic or mechanical circulatory obstruction?

Answer 47

massive PE

Question 48

if a fibrinolytic drug is given for suspected PE arrest, continue CPR for at least how long?

Answer 48

at least 60-90 minutes

Question 49

how to suspect and manage cardiac tamponade as the cause for an arrest?

Answer 49

focussed cardiac ultrasound can show a pericardial effusion
have strong suspicion if arrest after penetrating chest trauma/ post-cardiac surgery
consider resuscitative thoracotomy

Question 50

If CPR is successful and a decision is made to discontinue efforts, the patient should be observed for at least how long before confirming death?

Answer 50

5 minutes