Page 90 - WSAVA2017
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An Urban Experience
D. McBride1
1Royal Veterinary College, Queen Mother Hospital for Animals, London, United Kingdom
Royal Veterinary College, Hawkshead Lane, North Mymms, United Kingdom
CPR algorithms can be beneficial as we have to act quickly with not much time to think. The author uses the algorithm CABDEF to help with CPR (although on-line posters are also available). The CAB component if what is classed as basic life support, and the most important component of CPR. Once CAB is completed, DEF which is classed as advanced life support should be performed. It is important to identify a team leader, who will give directions so the CPR flows well.
Cardiac compressions are the most important part
of CPR and must commence within 10 seconds of identifying cardiac arrest. Cardiac arrest should be identified by auscultation of the heart, however if the witness is unsure, they should start compressions immediately if the animal is not breathing and non- responsive. Compressions are performed at 100 – 120 compressions per minute. There are 2 methods of compressions. For animals greater than 10 kg, thoracic compressions are performed. This involves creating enough intrathoracic pressure to compress the heart. Hands are placed at the highest/widest part of the thorax while the animal is in lateral recumbency. The thorax is compressed approximately 1/3 – 1⁄2 of the width of the thorax (which is usually achieved when compressing as hard as possible). It is important to have a compression to decompression ratio of 1:1 and to decompress (recoil) completely. Recoil is important for venous return and complete filling of the right atrium of the heart. Each cycle of compressions performed by one individual should last approximately 2 minutes; or shorter if compressions are ineffective (efficacy of compressions will be discussed below). It is important to time the change in cycles well
to minimise interruptions in CPR. When performing compressions in animals < 10 kg (or very flat chested dogs), external cardiac compressions are performed over the heart which is between the 3rd and 5th ribs (at the point of the elbow). It can be performed by 2 methods:
1) Thumb and fingers are placed on each side of the heart and compressions are performed by one hand; 2) Fingers of each hand are placed on each side of the heart and compressions are performed by using both hands.
The efficacy of CPR can be monitored by 3 methods:
1. Femoral pulse palpation: Each time an effective compression is performed, the femoral pulse should be palpable.
2. Capnography: ETCO2 of 15 – 20 mmHg should be achieved with successful compressions; less than this is ineffective compressions. ETCO2 > 35 mmHg suggests return of spontaneous circulation (ROSC).
3. Doppler: The Doppler probe which is used to measure blood pressure can be applied to the surface of the cornea with any type of conduction gel. Every time an effective compression is performed, a pulse should be audible. However care must be taken not to interpret interference noise as a pulse.
To maintain patency of the airways, endotracheal intubation must be performed. If intubation is difficult, a ridged canine urinary catheter can be used as a stylet. Once the ET tube is placed, the cuff must be inflated
and the tube secured with a tie. Once intubated, there may be more airway secretions which accumulate in
the ET tube. A sterile suction catheter can be used to aspirate respiratory secretions. If intubation is impossible, emergency tracheostomy can be performed, however majority of the time intubation should be possible with the guide of the canine urinary catheter.
Ventilation should be performed either using an anaesthetic circuit with 100% oxygen and a rebreathing bag, with the maximum pressure of each breath 20 cmH2O. An ambu bag attached to an oxygen source can also be used, and may be safer as the is a safety release valves so the pressure of each breath cannot exceed 20 cmH2O, no matter how hard you compress the ambu bag. Ventilation is performed by giving 1 breath every 6 – 8 seconds.

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