CPR

Question 1

What is ROSC?

Answer 1

Return of spontaneous circulation

Question 2

What is the in-hospital mortality of patients who survive a cardiac arrest?

Answer 2

71%

Question 3

What is post-cardiac arrest syndrome?

Answer 3

AKA post-resucitation syndrome

Occurs following ROSC following cardiorespiratory arrest, involves multiple systems

Severity depends on the duration and cause of cardiac arrest

Question 4

Causes of death following cardiac arrest

Answer 4

Early: due to cardiovascular intability

Late: brain injury (most common), multi organ failure and sepsis

Question 5

Mechanism of post-cardiac arrest syndrome

Answer 5

Thought to be due to production of free radicals during hypoxia

🧠 1. Brain injury: ischaemia or hyperaemia due to micro and macro circulatory compromise

🫀 2. Myocardial dysfunction: hypokinesis occurs aka myocardial stunning, decreased heart wall motion

3. Ischaemia/ reperfusion response: release of inflammatory cytokines
4. Persistent precipitating pathology: the cause of the cardiac arrest continues to impact on physiological parameters

Question 6

Management following ROSC

Answer 6

A-E

A: if patient not waking 10-15mins after ROSC then intubate

B: maintain sats 94-98%

C: aim for MAP 65-100 and use arterial line to continually monitor

D: record GCS before any sedation, control seizures (they cause metabolism to be 3x which quickly causes hypoxia)

E: control temp

G: glucose: avoid hypoglycaemia

Identify and treat underlying pathology

Question 7

Discuss post-cardiac arrest hypothermia

Answer 7

Mild hypohtermia may suppress chemical reactions associated with reperfusion injury following arrest

There is some evidence that all survivors of cardiac arrest benefit from mild hypothermia

ALS group recommend cooling the patient to 32-34 degrees for 12-24hrs after an out of hospital arrest but evidence is mixed

Pyrexia must be prohibited after arrest

Question 8

Clinical features of cardiac arrest

Answer 8

Suspect in any patient who is unconscious and does not have signs of life

Pulse: check for a central pulse for no more than 10s

> Other confirmatory clinical features e.g. colour, pupil size or response waste time and do not help

Respiratory efforts may persist for several mins after arrest

Question 9

Information to obtain from ambulance crew/ relatives

Answer 9

Patient details: age, PMHx, current medication, chest pain before event

Time of collapse, 999 call, start of CPR, first defib shock, other management and ROSC

Any bystander CPR?

Question 10

Discuss the team in a cardiac arrest case

Answer 10

Hospital will have be pre-alerted by ambulance and therefore team ready in resus with equipment needed

Team leader: controls and coordinates the CPR

4-6 team members is optimal

Each member should know role

Perform CPR with minimal interruption unless when using defib

Question 11

What to do when encountering a collapsed or sick patient?

Answer 11

Call for help

Assess patient

Signs of life?

Yes: assess A-E, recognise and treat, call resus team if needed

No: call resus team, CPR 30:2, apply defib and assess rhythm, shock if appropriate, ALS when tram arrives

Question 12

How long should each breath last when giving CPR?

Answer 12

~1s

Question 13

Rate of chest compressions

Answer 13

100-120/min

Question 14

How far away from a pacemaker should a defib pad be?

Answer 14

>15cm

Question 15

How long, after giving a defib shock, should we continue CPR before checking rhythm?

Answer 15

2 mins

Question 16

What can be done for patients in a shockable rhythm when a defib is not immediately available?

Answer 16

Precordial thump: tighly clench fist and give one direct blow from 20cm to the lower 1/2 of the sternum

Question 17

How can we confirm correct tracheal tube placement?

Answer 17

End tidal CO2 - partial pressure of CO2 at the end of an exhaled breath

Detected by a sensor located between the patients airway and the ventilator

Question 18

Routes of drug administration in cardiac arrest

Answer 18

Peripheral cannula: useful to flush the drug through with saline and elevate the limb when given

Central venous cannulation isn’t recommended because its time consuming, tricky and interrupts CPR

Intra-osseus infusion is also an option

Not recommended to put drugs down ET tube or to give intracardiac injections

Question 19

Drug of choice in cardiac arrest

Answer 19

Adrenaline

Given after 3 shocks in VF or pulseless VT

Given immediately in asystole/ PEA

Question 20

What is PEA?

Answer 20

Pulseless electrical activity

The clinical situation of cardiac arrest with an ECG trace compatible with a cardiac output

Question 21

What can cause PEA?

Answer 21

Failure of the pump:

• MI, drugs e.g. b-blockers/ calcium antagonists, electrolyte disturbances e.g.hypo/hyperkalaemia

Obstruction to cardiac filling or output:

• Tension pneumothorax (compresses heart and prevents filling), tamponade, myocardial rupture, PE, prosthetic valve occlusion, hypovolaemia

Question 22

How long do we do CPR for?

Answer 22

Depends on the situation, time since onset and estimated prospect of survival

Generally: always continue whilst patient is in a shockable rhythm, try changing pad position if repeated defib attempts do not work

Asystole lasting >1hr is rarely associated with survival

>>> exceptions being asystole in the young, hypothermia, near drowning and drug overdose <<<

Question 23

ALS CPR algorithm revision

Answer 23

Question 24

What should be given to patients in torsades de pointes and refractory VF due to digoxin toxicity or hypomagnesaemia?

Answer 24

Magnesium sulfate

Question 25

Which vessels are used for central venous access?

Answer 25

Internal jugular and subclavian veins

Risk of subclavian cannulation is pneumothorax so jugular is preferred

USS guidance is used, right side of neck is ideal as less risk of thoracic duct damage

Femoral vein is used for temporary access in severe trauma and burns