Cardiopulmonary resuscitation (CPR)

Question 1

Cardio-pulmonary arrest (CPA)

Answer 1

Cessation of ventilation and systemic perfusion

low survival rate, higher if already under GA

Question 2

Equipment needed on resuscitation trolly

Answer 2

Drugs
Saline flush
ET tubes
Laryngoscope
IV catheters
Tape
Fluid therapy

Question 3

Basic life support

Answer 3

Initiate CPR immediately

Chest compressions (100-120/min)
Ventilation (10/min)
C:V ratio = 30:2

Question 4

Advances life support

Answer 4

Initiate monitoring
- ECG
- End Tidal CO2

Obtain vascular access

Administer reversals

Question 5

Reversal drugs

Answer 5

Opioids: naloxone

Alpha-2 agonists: atipamezole

Benzodiazepines: Flumazenil

Question 6

How to recognise a CPA event?

Answer 6

Unresponsive patient
Absence of breathing/abnormal breathing
Absence of palpable pulse
Change in heart rhythm

Question 7

Recognising a CPA event on End-tidal CO2

Answer 7

Decreasing or flatlines

Question 8

CPA event on ECG

Answer 8

Ventricular fibrilation - not coordinated so no CO

Ventricular tachycardia - no P wave, usually higher than 180bpm

Asystole - no electrical activity

Pulse-less electrical activity - no peripheral pulse but electrical activity at the heart

Question 9

Chest compressions

Answer 9

100-120/min

Compress 1/3 to 1/2 width of the chest

Allow full chest recoil

Minimise interruptions and delays in starting compressions

Rotate person every 2 min cycle - check for pulse/evaluate ECG

Question 10

Cardiac pump theory

Answer 10

Direct compression of heart

For small dogs, cats, and keel chested dogs

Question 11

Thoracic pump theory

Answer 11

Chest compression on widest portion of chest

For barrel chested dogs, and round chested dogs

Question 12

Securing the airways

Answer 12

Remove any obstructions by suction or removal

Intubate

Question 13

Ventilation

Answer 13

10 breaths/min

Before/without intubation - mouth to snout

Inspiratory time 1sec

Look at chest excursions

O2 100%

Avoid hyperventilation -> cerebral vasoconstriction

If high positive pressure administered -> decreased venous return and CO

Question 14

Vascular access

Answer 14

IV - catheter, ideally cranial to heart

Intraosseus - often needed in puppies and kittens

Intratracheal (dilute and increase dose) - drug absorbed by tracheal mucosa

Question 15

Drug therapy

Answer 15

Reversal agents

Vasopressors (epinephrine, vasopressin)

Anticholinergic (atropine)

Anti-arrhythmic (lidocaine, amiodarone)

Question 16

Epinephrine/adrenaline

Answer 16

Low dose: 0.01mg/kg IV/IO every other cycle of CPR

High dose: 0.1 mg/kg IV/IO (long CPR)

Vasoconstriction and increased contractility

Less effective in acidotic environment

Cheap

Question 17

Vasopressin

Answer 17

Not widely used in veterinary

0.8 U/kg IV/IO

Vasoconstriction, no ionotropic or chronotropic effects

Effective in acidotic environment

Expensive

Question 18

Atropine

Answer 18

Anticholinergic - inhibits PS system

0.04 mg/kg IV/IO every other BLS cycle

Rapid onset of action

Increases HR and contractility

Can be alternated with adrenaline in cases of asystole of AV blocks

Question 19

Amiodarone

Answer 19

Class III anti-arrhythmic, also with class I, II, and IV effects

For refractory Ventricular Fibrillation/ Pulseless Ventricular Tachycardia

Risk of anaphylactic reactions and hypotension

Question 20

Lidocaine

Answer 20

Class I anti-arrhythmia, Na+ channels

For refractory Ventricular fibrillation/pulseless Ventricular Tachycardia (if amiodarone is not available)

Much cheaper

Question 21

When is defibrillation possible?

Answer 21

Ventricular fibrillation

Pulseless ventricular tachycardia

Question 22

When is defibrillation not possible?

Answer 22

Asystole

Pulseless electrical activity

Question 23

How to carry out defibrillation

Answer 23

Dorsal recumbency: paddles placed on opposite sides of the chest

Conductive gel on both paddles (not US gel!!)

‘Check for clear’

Question 24

Defibrillation

Answer 24

Monophasic or biphasic depending on direction of currect accross the myocardium

Newer defibrillators are usually biphasic

Question 25

Joules provided by Biphasic defibrillation

Answer 25

2-4 J/kg

Question 26

Joules provided by monophasic defibrillation

Answer 26

4-6 J/kg

Question 27

Phases of ischaemia in CPA

Answer 27

Electrical phase - first 4 mins: minimal ischaemic damage - energy stores available - shock immediately

Circulatory phase - 4-10 mins: reversible ischaemic damage - ATP depletion - Shock after a full CPR cycle

Metabolic phase - >10 mins: irreversible ischaemic damage - shock after full CPR cycle

Question 28

When to consider open chest CPR

Answer 28

CPA occurs intraoperatively

External compression might not be effective (pneumothorax, cardiac tampenade, diaphagmatic hernia)

XXL dogs

Question 29

Acid/base and electrolytes therapy

Answer 29

Evaluation of blood gas analysis, electrolytes, glucose

Metabolic acidosis treated with SODIUM BICARBONATE

Hyperkalaemia

Hypokalaemia

Glucose administration is not recommended unless hypoglycaemic

Question 30

Treatment of metabolic acidosis

Answer 30

Recommended if pH<7

Sodium bicarbonate 1mEq/kg dilutes IV over 15 mins

Question 31

Normal end tidal CO2 values

Answer 31

35-45 mmHg

Question 32

Return of spontaneous circulation (ROSC)

Answer 32

Respiratory rate and effort (should normalise - no gasping, agonal breathing etc.)

ECG (heart rate and rhythm)

Palpable pulse and blood pressure measurement

MM come back to normal

Pupil size and responsiveness, and other reflexes

Question 33

Post CPR care

Answer 33

Re-arrest common monitoring is essential

Maintain perfusion and O2 supply to organs

Ventilation + O2 supplementation if required

Vasopressors, positive inotropes to maintain blood pressure and HR

Fluid therapy if haemorrhage/hypovolaemia

Avoid hyperthermia, slight hypothermia is better

Consider analgesia, but beware of side effects