Page 542 - WSAVA2018
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 25-28 September, 2018 | Singapore
performing observations and monitoring vital signs. Communicate what you are observing and how effective is the CPR being performed.
Recording - Recording all actions, drugs administered with doses and time, time CPR was started and time the 2 minute cycles of CPR.
Cardiac arrest will shortly follow respiratory arrest often if not occurring at the same time. Cardiopulmonary arrest occurs when cardiopulmonary function fails.
The aim of cardiopulmonary resuscitation is to restore cardiac function and circulation. This is done by
creating adequate pressure in the thoracic cavity by compressing the chest wall to stimulate cardiac output and create adequate venous return. There are two ways of performing cardiopulmonary resuscitation, external cardiac massage and internal cardiac massage.
External cardiac massage
There are two methods of external cardiac massage depending on the size of the animal.
Patient Positioning – Experimental evidence suggests higher left ventricular pressures and aortic blood flow
in dogs in lateral recumbency compared to dorsal recumbency and higher rates of return of spontaneous circulation in compressions performed in lateral recumbency suggest that this is the ideal position. Either left or right is now considered acceptable although right lateral is preferred. However there are great variations in chest conformation among dogs and cats so a single identical approach to compressions is unlikely to work.
Cardiac Pump (Patients under 20kg)
The cardiac ventricles are directly compressed between the sternum and spine in patients in dorsal recumbency and between the ribs in lateral recumbency. This method is most suitable for patients weighing less than 20 kg. The patient is placed in lateral recumbency and the chest wall is compressed by placing both hands on the upper side of the chest wall at a rate of 100 - 120 compressions per minute. The chest should be compressed to 30 – 50% of its circumference. In very small patients such as cats the chest can be compressed between the thumb and forefinger with the thumb being on the upper side
of the chest wall. Ventilation is given simultaneously with compression at 1 breath every 5 seconds. Continue the cycle for 2 minutes without interruption.
Thoracic Pump (Over 20 kg)
Chest compressions increase the overall intrathoracic pressure, secondly compressing the aorta and collapsing the vena cava leading to blood flow out of the thorax. During the elastic recoil of the chest, sub atmospheric intrathoracic pressure provides a pressure gradient that favours the flow of blood form the periphery back into
the thorax and into the lungs where oxygen and carbon dioxide exchange occurs.
This method is most suitable for patents weighing
over 20 kg or medium, large or giant breeds with
round chests. The patient can be in lateral or dorsal recumbency. The chest is compressed to 30 – 50% of its circumference by placing both hands on the widest point of the chest. Ventilation is simultaneously supplied to increase the thoracic pressure also at 1 breath every 5 seconds. Continue the cycle for 2 minutes without interruption.
Abdominal counter compressions
Abdominal counter compressions can help with
venous return and improve cardiac output. By
applying abdominal compressions alternate to chest compressions the blood is forced to the chest cavity
for more effective cardiopulmonary resuscitation. If abdominal compressions are not possible then binding the hind limbs and abdomen with bandages (Vetwrap) helps to create the same effect. There have been some reports of injury to abdominal organs in some cases when counter compressions are applied. Therefore this is often used as a last resort method.
Internal Cardiac Massage
This method is not common as it involves opening the chest and hence a surgical approach. Clip the hair on the chest between the sternum and chostochondral junction and apply a quick surgical scrub. The veterinarian will make an incision between the 4th and 5th ribs and spread them apart with retractors while delicately moving the lungs. The pericardium is then grasped and the heart compressed with a thumb and forefinger. It is important that IPPV is maintained throughout this process.
LOOK AT THE ANIMAL! If the respiration rate is slow and the mucous membrane colour is pale to grey then respiratory arrest is often not too far off. Agonal gasps are generally a clear indicator of cardiac arrest or imminent arrest. Ensure a patent airway. Wipe or suction away any debris in the mouth and airway such as blood, vomitus or foreign objects.
If the animal is in actual respiratory arrest (not breathing at all) then an appropriate sized endotracheal tube must be placed down the trachea and the cuff inflated. Attach the tube to an oxygen source which ideally would be
an Ambu bag but the anaesthetic machine is adequate however ensure the vaporiser is turned OFF and the circuit closed. Commence Intermittent Positive Pressure Ventilation (IPPV). One breath every 5 seconds at a tidal volume of 10ml/kg. If you can monitor ETCO2 with a capnograph a measurement of at least 15 mm Hg will

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