Cardiorespiratory arrest and ALS

Question 1

What are the most common potentially reversible causes of cardiac arrest?

Answer 1

four Hs and four Ts

• Hypoxia, Hypovolaemia, Hypo/Hyperkalaemia, Hypothermia
• Thrombosis, Tamponade, Toxins, Tension pneumothorax

Question 2

If the most likely cause of a cardiac arrest is identified as hypoxia, how should this be managed?

Answer 2

• Ensure the airway is patent
• Ventilate the lungs using high-flow oxygen
• Although it has been common practice to hyperventilate a patient in cardiac arrest based on the premise that this will help to reduce any hypercarbia, this practice should be avoided as hyperventilation reduces coronary perfusion pressure and worsens outcome.

Question 3

What would suggest that hypovolaemia is the cause of cardiac arrest? How should this be managed?

Answer 3

• Clues to hypovolaemia may come from the patient’s history, observation charts or clinical examination.
• The cause of hypovolaemia may be obvious (e.g. blood loss or severe diarrhoea) or more subtle (e.g. severe sepsis or anaphylaxis).
• If hypovolaemia is suspected, rapidly infuse intravenous fluids.

Question 4

How would you rule out hyper/hypokalaemia as the cause of cardiac arrest?

Answer 4

• Near-patient-testing equipment allows the rapid measurement of potassium and glucose.
• Review the patient’s latest laboratory results.

Question 5

How should hyperkalaemia be managed if found to be the cause of the cardiac arrest?

Answer 5

Immediate treatment of hyperkalaemia is administration of calcium chloride followed by insulin/dextrose infusion.

Question 6

How should hypokalaemia be managed if found to be the cause of a cardiac arrest?

Answer 6

Low potassium/magnesium levels may be treated with an infusion of a solution containing the deficient substance.

Question 7

Is hypothermia a common cause of in-hospital cardiac arrest?

Answer 7

No - it is rare

Question 8

How would you rule out hypothermia as the cause of cardiac arrest?

Answer 8

Measure core temperature with a low-reading thermometer. (rectal thermometer)

Question 9

How should hypothermia be managed if found to be the cause of cardiac arrest?

Answer 9

Use active re-warming techniques to treat a hypothermic patient in cardiac arrest.

Cardiopulmonary bypass may be considered if facilities are immediately available and active re-warming strategies fail.

Question 10

Coronary thrombosis is a common cause of cardiac arrest. What should be done if coronary thrombosis is suspected to be the cause of cardiac arrest?

Answer 10

• If an ACS is suspected as the cause of refractory cardiac arrest it may be feasible to perform percutaneous coronary angiography and percutaneous coronary intervention during ongoing CPR.
• This would require the use of an automated CPR device and/or extracorporeal CPR to maintain circulation during the procedure.

Question 11

Which conditions are classified as a ‘thrombosis’ cause of cardiac arrest?

Answer 11

• Coronary thrombosis
• Massive pulmonary embolism

Question 12

If a massive pulmonary embolism is found to be the cause of cardiac arrest, how should the patient be managed?

Answer 12

• Consider giving a fibrinolytic drug immediately.
• Survival and good neurological outcome have been reported in cases requiring prolonged CPR. Consider performing CPR for at least 60-90 min in this setting.

Question 13

Which cause of cardiac arrest warrants performing CPR for a prolonged period of time e.g. 30-90 mins?

Answer 13

Massive PE

Question 14

When should cardiac tamponade be considered as the cause of cardiac arrest?

Answer 14

Tamponade should be considered after penetrating chest trauma or after cardiac surgery, device implantation (e.g. pacemaker) and percutaneous coronary intervention.

Question 15

If you are suspecting cardiac tamponade as the cause of cardiac arrest, how should the diagnosis be confirmed?

Answer 15

Cardiac tamponade is difficult to diagnose without focussed cardiac ultrasound as many of the features on clinical examination are difficult or impossible to elicit during cardiac arrest.

Question 16

What is the management of cardiac tamponade?

Answer 16

Treatment is with either needle pericardiocentesis or resuscitative thoracotomy.

Question 17

When should drug toxicity be considered as a cause of cardiac arrest?

Answer 17

Drug toxicity is a relatively unlikely cause of cardiac arrest unless there is evidence of deliberate overdose or suspicion of substance abuse.

For in-patients, a review of the patient’s drug chart may be helpful.

Question 18

What should be checked in an intubated patient who has arrested?

Answer 18

In an intubated patient patient check the tube position as intubation of the right main bronchus can further complicate a tension pneumothorax, which can be difficult to diagnose during cardiac arrest.

Question 19

What would suggest tension pneumothorax as the cause of cardiac arrest?

Answer 19

It may be indicated by unilateral expansion of the chest, shift of the trachea, or subcutaneous emphysema.

Pleural ultrasound in skilled hands is faster and more sensitive than chest X-ray for the detection of pneumothorax.

Question 20

How should tension pneumothorax be managed?

Answer 20

Early needle decompression (thoracocentesis) followed by chest drain insertion is needed. Needle decompression may fail if the needle used is too short.

In a ventilated patient, thoracostomy (a surgical hole in the chest wall and pleura) may be quicker to perform and more effective in releasing the tension.

Question 21

It is now 5 mins into CPR. The anaesthetist has already ventilated the patient. The end-tidal CO2 has risen to 5.2 and the defibrillator is now showing sinus rhythm.

Should you continue with CPR or reassess the patient with an A-E approach?

Answer 21

The sudden rise in end-tidal CO2 suggests return of spontaneous circulation. When this is seen or when a patient starts displaying signs of life e.g. sinus rhythm, chest compressions should be paused and patient should be reassessed.

Question 22

What is capnography used for?

Answer 22

Capnography represents the amount of carbon dioxide in exhaled air.

This assesses ventilation, which is different from oxygenation.

Question 23

What is the difference between ventilation and oxygenation?

Answer 23

Ventilation is the air movement in and out of the lungs, while oxygenation is the amount of oxygen inhaled by the lungs that reaches the bloodstream.

Question 24

How do you measure capnography?

Answer 24

Two sensors can be used to measure capnography.

• In patients who are breathing, nasal prongs can be applied that capture exhaled air. Those prongs can also be used to administer a small amount of oxygen, or applied underneath a non-rebreather or CPAP mask.
• In patients who require assisted ventilation, another adapter can be attached to a BVM and advanced airway device.

Question 25

Once an anaesthetist has placed an advanced airway, how should you continue compressions?

Answer 25

continuous compressions (no need to pause for the 2 breaths because patient is being mechanically ventilated)

Question 26

Which rhythms are shockable?

Answer 26

Pulseless ventricular tachycardia

Ventricular fibrillation

Question 27

Which rhythms are non-shockable?

Answer 27

Pulseless electrical activity

Asystole

Question 28

True or false?

When assessing breathing, occasional gasps are a sign of life.

Answer 28

false

Question 29

True or False?

A pulse check should be done at every rhythm assessment.

Answer 29

False - Pulse checks should be performed only when organised electrical activity compatible with a pulse is seen.

Question 30

True or False?

When it is a shockable rhythm, adrenaline should always be withheld till after the 3rd shock.

Answer 30

Once given, adrenaline should be repeated every 3-5 min, irrespective of cardiac arrest rhythm.

In primary VF/pVT, adrenaline is withheld until after the third shock.

Question 31

If IV access cannot be achieved within 2 minutes of resuscitation, what should be done?

Answer 31

intraosseous access should be considered

Question 32

When should adrenaline be given in asytole/PEA?

Answer 32

When considering the treatment of PEA/Asystole, give 1mg adrenaline as soon as vascular access is achieved.

Question 33

When is external pacing helpful?

Answer 33

external pacing may be effective for ventricular standastill with continued atrial activity (sometimes called ‘P-wave asystole’), but is unlikely to be effective in total asystole

Question 34

What depth should compressions be?

Answer 34

5-6cm

Question 35

What rate should compressions be given at?

Answer 35

100-120 compressions/min

Question 36

Should the chest wall be allowed to recoil between chest compressions?

Answer 36

yes

Question 37

Where is the correct position for chest compressions?

Answer 37

centre of lower third of sternum

Question 38

What percentage of people survive after receiving CPR for in-hospital cardiac arrest?

Answer 38

approx 20%

Question 39

What percentage of people survive after receiving CPR for out-of-hospital cardiac arrest?

Answer 39

approx 10%

Question 40

Why do we not attempt resuscitation in everyone?

Answer 40

attempting CPR on a person who is dying from an irreversible condition has no benefit and will deprive them and their family of a peaceful and dignified death

Question 41

Because for some people CPR offers more risk than benefit, a decision made in advance about whether or not to attempt CPR in the event of cardiorespiratory arrest is an important part of good-quality care for any person who is approaching the end of their life or who may be at identifiable risk of cardiorespiratory arrest.

Name 5 potential risks of CPR.

Answer 41

• Fractured ribs
• Trauma to internal organs
• An undignified death
• Prolonging suffering by bringing the person back to continued poor quality of life that they would not have chosen
• Increasing suffering by bringing the person back to a worse state than before

Question 42

Should healthcare professionals make decisions about CPR based on what they would want for themselves if they were in a similiar situation?

Answer 42

No. Every decision about CPR must be made on the basis of a careful assessment of each individual’s situation. Decisions about CPR must be free from any discrimination, for example in respect of a disability or a person’s age.

Question 43

Who should be involved in decision making about CPR?

Answer 43

That process should involve the wider healthcare team, the patient and (in most circumstances) those close to the patient.

The courts have stated that there should be a presumption in favour of involving the patient in the process of decisions about CPR.

Question 44

When are DNACPR decisions made?

Answer 44

the person is dying from an irreversible advanced condition, so attempting CPR when their heart stops would not prevent their death and may cause harm

Question 45

If a doctor decides that CPR would not prevent death in a patient and instead, is likely to cause harm, what should be done?

Answer 45

Where CPR would not work it should not be offered or attempted. The patient should still have the decision and the reason for DNACPR should be explained to them, unless they specifically decline discussion about CPR.

The decision and the reason for it should also be explained to those close to the patient unless the patient does not want that

Question 46

A doctor decides that DNACPR is in a patient’s best interest. The patient and the family disagrees with the decision. What are the next steps?

Answer 46

Explaining to a patient and those close to them that all the members of a multidisciplinary team agree that CPR would not work and that a DNACPR decision is needed may help them to accept that decision without the need for a further opinion.

If the patient and/or those close to them refuse to accept a decision a second opinion should be offered and arranged.

Question 47

If there is no reason to believe that a person is approaching the end of their life or likely to suffer cardiorespiratory arrest, should discussions about CPR be initiated?

Answer 47

Not routinely.

However, if a person does want to have those discussions or to make a decision about CPR they must be offered the opportunity to do so.

Question 48

What should you do if someone suffers sudden cardiorespiratory arrest unexpectedly and is not known to have recorded a decision about CPR?

Answer 48

If a person suffers sudden cardiorespiratory arrest unexpectedly and is not known to have a recorded decision about CPR those present should call for help and start CPR.

Question 49

You admit a patient, Mary. She is 83 and has been sent into hospital by her GP because of worsening, severe breathlessness at rest.

She has advanced heart failure for which she has a biventricular pacemaker and has been taking all appropriate medical treatment.

This is her third hospital admission in the past 4 months because of breathlessness. She also has a mild left hemiparesis following a previous stroke.

She has no RESPECT form. What would you about this?

Answer 49

• Inform a senior that a discussion about CPR may be appropriate
• Record a plan in the notes about any discussions and when this decision should be reviewed as Mary may change her views depending on her response to treatment

Question 50

A patient has an Advance Decision to Refuse Treatment (ADRT) specifically refusing CPR. Is this legally binding?

Answer 50

yes

Question 51

What specific details about a CPR decision should be documented?

Answer 51

decisions about CPR

the reasons for them

the discussions that informed those decisions

(this should be on a RESPECT form)

Question 52

When should CPR decisions be reviewed?

Answer 52

Triggers for review should include any request from the patient or those close to them, any substantial change in the patient’s clinical condition or prognosis or movement of the patient to a different location.

Question 53

Regarding in-hospital cardiac arrests, are shockable or non-shockable rhythms more common?

Answer 53

non-shockable (80%)

Question 54

Is survival more likely with a shockable or non-shockable rhythm?

Answer 54

shockable

Question 55

What is the typical story for a patient with a non-shockable rhythm in a in-hospital cardiac arrest?

Answer 55

Around 82% of cardiac arrests that occur in-hospital have non-shockable (PEA and asystole) rhythms and survival to discharge is poor (less than 10%). Such arrests occur more commonly in ward areas and often have a period of deterioration beforehand. Prevention of cardiac arrest is very important for this group.

Question 56

What is the typical story for a patient with a shockable rhythm in a in-hospital cardiac arrest?

Answer 56

Approximately 20% of in-hospital cardiac arrests have an initial shockable rhythm (VF/pVT). This is primarily due to myocardial ischaemia and survivors usually have a witnessed or monitored arrest. The prognosis for these patients is more favourable, around 40-50% surviving to hospital discharge.

Question 57

Defibrillator pads are usually placed in the pectoral/apical position. If there are implanted devices or if trauma does not allow this, what alternative pad positions can be considered?

Answer 57

Anterior/posterior or mid-axilla/mid-axilla placement may offer alternative sites for pad placement, but this should always be achieved with minimal interruption to chest compressions.

Question 58

What are shockable rhythms?

Answer 58

Ventricular fibrillation

Pulseless ventricular tachycardia

Question 59

What are non-shockable rhythms?

Answer 59

Asystole

Pulseless electrical activity

Question 60

What are the components of post-cardiac-arrest-syndrome?

Answer 60

• Post-cardiac-arrest brain injury
• Post-cardiac-arrest myocardial dysfunction
• Systemic ischaemia-reperfusion response
• Persistence of precipitating pathology

Question 61

How does post-cardiac-arrest brain injury present?

Answer 61

coma, seizures, myoclonus, varying degrees of neurological dysfunction and brain death

Question 62

What conditions/physiological states should we aim to prevent in post-cardiac-arrest brain injury?

Answer 62

impaired autoregulation, hyper/hypocarbia, hypoxia/hyperoxia, hypo/hyperglycaemia, pyrexia and seizures.

Question 63

What is post-cardiac-arrest myocardial dysfunction?

Answer 63

Significant myocardial dysfunction is common after cardiac arrest. This is called ‘myocardial stunning’ and may result in a temporary but significantly reduced left ventricular ejection fraction and therefore cardiac output. It typically recovers after 48 to 72 h.

Question 64

Describe the pathophysiology of systemic ischaemia-reperfusion response post-cardiac-arrest?

Answer 64

The whole body ischaemia/reperfusion that occurs after resuscitation from cardiac arrest activates immunological and coagulation pathways that cause multiple organ failure and increase the risk of infection.

Question 65

How does post-cardiac arrest systemic ischaemia-reperfusion response present?

Answer 65

The post-cardiac-arrest syndrome has many features in common with sepsis, including intravascular volume depletion and vasodilation. This should be treated with intravenous fluids, vasopressors and inotropes as required to maintain end organ perfusio

Question 66

Do all patients require tracheal intubation and ventilation post-cardiac arrest?

Answer 66

Spontaneously breathing patients do not require tracheal intubation and ventilation, but should be given oxygen by facemask to maintain normal arterial oxygen saturation.

Consider tracheal intubation, sedation, and controlled ventilation in any patient with obtunded cerebral function.

Question 67

After SROC post-cardiac arrest, you should ensure that the patient is ventilating well with good oxygenation. This is achieved with a facemask or tracheal intubation. You should then examine the chest for what?

Answer 67

Examine the patient’s chest by looking and feeling for symmetrical chest movement and crepitus. If ribs have been fractured during chest compressions there may be a pneumothorax, flail segment or both.

Listen to ensure that breath sounds are equal on both sides. A tracheal tube that has been inserted too far will tend to go down the right main bronchus and fail to ventilate the left lung. You should also listen for evidence of pulmonary oedema, pulmonary aspiration of gastric contents or wheeze.

Question 68

After spontaneous return of circulation, you have attached an oxygen facemask and examined the chest. What would you do next?

Answer 68

Insert a gastric tube - this will decompress the stomach following mouth-to-mouth or bag-mask ventilation, prevent splinting of the diaphragm and enable drainage of gastric contents.

If the intubated patient regains consciousness soon after ROSC and is breathing normally, consider immediate extubation. Ensure that a rigid sucker is available.

If immediate or early extubation is not possible, sedate the patient to ensure the tracheal tube is tolerated and provide ventilatory support.

Ensure the airway is secure before transfer.

Question 69

What could grossly distended neck veins when a patient is semi-upright indicate in a post-cardiac arrest patient?

Answer 69

right ventricular failure, but in rare cases could indicate pericardial tamponade

Question 70

How would you monitor for end-organ perfusion in a post-cardiac arrest patient?

Answer 70

Brain - decreased conscious level may indicate hypoperfusion

Heart - chest pain indicates inadequate perfusion

Kidneys - Insert a urinary catheter and aim for a urine output of > 1 mL-1kg-1h-1.

Question 71

Name 5 things that should be monitored in a patient post cardiac-arrest.

Answer 71

vital signs

ECG

pulse oximetry

blood pressure - continuous monitoring using an arterial line is preferable

capnography

urine output

temperature

Question 72

Name 4 post-resuscitation investigations that should be conducted.

Answer 72

Arterial blood gas analysis is valuable for documenting the severity of the likely metabolic, and probably respiratory, acidosis. The effectiveness of continued resuscitation can be confirmed by documenting reducing lactate values and correction of base deficit. It also acts as a point of care test for important electrolytes such as potassium and sodium.

A full blood count will exclude anaemia as contributor to myocardial ischaemia and provide baseline values. Check the plasma biochemistry, including blood glucose and a troponin.

Repeat the 12-lead ECG and request a chest X-ray.

Echocardiography is very useful because it may identify potential reversible causes of cardiac arrest and will enable assessment of ventricular structure and function.

Question 73

A typical post-resuscitation x-ray

What is shown by the different arrows?

Answer 73

endotracheal tube placed correctly

right internal jugular central line

right upper lobe collapsed with loss of lung volume

defibrillator pad placed correctly

Question 74

Where should a patient be transferred post-resuscitation?

Answer 74

ITU or CCU

Question 75

What is an intra-aortic balloon pump?

Answer 75

IABP (intra-aortic balloon pump). These are often inserted post-PCI. They are inserted into the aorta via the femoral artery and are programmed to inflate during diastole. This increases the intra-aortic pressure during diastole, which ultimately increases coronary artery perfusion as this takes place almost exclusively during this stage of the cardiac cycle.

If treatment with fluid resuscitation and vasoactive drugs is insufficient to support the circulation, consider insertion of an intra-aortic balloon pump.

Question 76

Why are patients sedated after resuscitation?

Answer 76

The patient is usually sedated with a combination of opioids and hypnotics - short-acting drugs will enable earlier neurological assessment.

Adequate sedation will reduce oxygen consumption.

During hypothermia, optimal sedation can reduce or prevent shivering, which enables the target temperature to be achieved more rapidly. This may require muscle relaxants.

Question 77

There is evidence from RCTs that supports induced mild hypothermia in comatose survivors of which type of cardiac arrest?

Answer 77

comatose survivors of out-of-hospital cardiac arrest caused by VF.

This therapy may benefit patients after non-shockable rhythms or in-hospital cardiac arrest, but the evidence in these patients is more limited.

Question 78

What are the physiological effects of hypothermia? (5)

Answer 78

Question 79

At what point can you reliably predict poor outcome in adult patients who are comatose after cardiac arrest, who have not been treated with hypothermia and with no confounding factors?

Answer 79

Absence of both pupillary light and corneal reflexes at >/= 72hr

Question 80

How can mild hypothermia be initiated post-resuscitation?

Answer 80

rapid infusion of 2 litres of ice cold crystalloid solution and the target temperature is 32 - 36°C.

Question 81

When implementing mild hypothermia after cardiac arrest, should cooling be delayed until the patient is admitted to an ICU?

Answer 81

Cooling should not be delayed; it should be initiated as soon as possible

Question 82

What is the most common cause of cardiac arrest in UK?

Answer 82

Acute coronary syndrome

Question 83

Coronary artery disease is the commonest cause of cardiac arrest and sudden cardiac death in adults. What are other cardiac causes of cardiac arrest?

Answer 83

structural heart disease

arrhythmias - complete heart block, long QT syndrome

Question 84

What type of cardiac arrest is common in patients <35 years old?

Answer 84

Inherited conditions e.g. hypertrophic cardiomyopathy

Question 85

What should be done once return of spontaneous circulation is achieved?

Answer 85

• Carry out a clinical examination
• Record a 12-lead ECG
• Arrange echocardiography

Question 86

A previously fit 21-year-old man suffers loss of consciousness whilst playing in a football match. He recovers after a couple of minutes.

What immediate actions would you take?

Answer 86

• take a detailed family history - Syncope during exercise is a ‘red flag’ symptom for the possibility of an underlying cardiac abnormality. A detailed family history is needed, to include checking for evidence of sudden death or syncope in family members. This may point to an inherited cardiac condition.
• arrange immediate clinical assessment and 12-lead ECG - Immediate clinical assessment and 12-lead ECG may detect evidence of structural heart disease (e.g. a cardiac murmur or ECG abnormality) or of an inherited condition (e.g. long QT syndrome, Brugada syndrome).

Question 87

A 68-year-old lady had a total hip replacement yesterday. After getting out of bed for the first time today she experienced severe central chest pain that has persisted for 30 min. She has a confirmed diagnosis of STEMI. There is no provider of PCI in a hospital nearby. What is the alternative option?

Answer 87

Advice from cardiologist at nearest PCI providing hospital as to whether she should be transferred as this is her only option or whether other anti-thrombotic therapy should be given.

Fibrinolytic therapy is contraindicated in view of surgery the previous day.