CPR.docx

**[CPR:]** 1. **[Learning Objectives:]** Welcome to Week Three, Lesson Three of Emergency and Critical Care. During this lesson, we will talk through what causes cardiopulmonary arrests, the ethics surrounding performing CPR and the expected outcomes. We will also discuss how being prepared both...

**[CPR:]** 1. **[Learning Objectives:]** Welcome to Week Three, Lesson Three of Emergency and Critical Care. During this lesson, we will talk through what causes cardiopulmonary arrests, the ethics surrounding performing CPR and the expected outcomes. We will also discuss how being prepared both in terms of equipment and as a team can really help, explore how to perform basic and advanced life support, and what is involved in post-arrest care. **By the end of this lesson, you should be able to:** 1. Explain the causes of cardiopulmonary arrest and which patients might make the best candidates for resuscitation; 2. Recall the components of basic life support (ABC); 3. Outline what equipment and training might be helpful to manage arrest situations; 4. Consider the options for more advanced life support; 5. Reflect on the likely outcomes of cardiopulmonary resuscitation. 2. **[Introduction:]** Unexpected cardiopulmonary arrests are generally very stressful situations. It is essential to be prepared for this emergency situation and ensure you have the necessary knowledge, equipment and skills to deal with a cardiopulmonary arrest. Full cardiopulmonary arrest (CPA) is defined as the sudden cessation of spontaneous and effective respiration and circulation. Cardiopulmonary resuscitation (CPR) provides circulatory and respiratory support, during efforts to produce the return of spontaneous circulation. Although published survival rates in veterinary patients following CPR are low, patients fall into TWO categories; those that arrest due to irreversible causes (i.e. as the end stage of their disease) and those that have reversible causes, (such as anaesthetic overdoses or electrolyte imbalances). It is therefore important to consider whether CPR is appropriate for all patients, however, where reversible causes are present, CPR can be very rewarding. 3. **[The Recover Study:]** Recently there has been a lot of discussion around CPR, particularly centred around the discovery in human medicine that early defibrillation improves outcome dramatically. In people, out of hospital arrests are more commonly associated with ventricular fibrillation (this is an uncommon arrest rhythm in dogs and cats), and for every minute you are not defibrillated, your chances of survival go down by 10%. Since this finding, electrical defibrillators have become commonplace in areas where people congregate (i.e. in the workplace, shops, airports etc.). Evidence based medicine in man has led to an improvement in outcome to around 20% survival post arrest. Until recently, there was not a uniform approach to CPR in dogs and cats. The RECOVER study, led by the Veterinary Emergency and Critical Care Society (VECCS) and the American College of Veterinary Emergency and Critical Care (ACVECC), systematically reviewed the experimental and clinical evidence in cardiopulmonary resuscitation research and devised a series of evidence-based, consensus CPR guidelines for dogs and cats. This project was a unique undertaking in veterinary medicine and will serve as a model for the future development of true evidence-based clinical guidelines for many important diseases and conditions of animals.  **Take a moment to review the RECOVER initiative guidelines.** The RECOVER study provided reviews in each of five domains (Preparedness and Prevention, Basic Life Support, Advanced Life Support, Monitoring, and Post-Cardiac Arrest Care), and a full description of the new clinical CPR guidelines, including a new algorithm and drug dosing charts. In addition, the authors have highlighted the level of evidence supporting each guideline and have identified important knowledge gaps in the literature that will serve as a roadmap for future veterinary CPR research. It is the hope of the RECOVER initiative participants, that this body of work will serve as a foundation for the development of training tools for veterinary surgeons, veterinary technicians and pet owners, ultimately leading to improved outcomes in dogs and cats that experience cardiopulmonary arrests. These guidelines are due for review in 2020 and updated guidelines should follow at regular intervals. RECOVER Guidelines ================== ### Veterinary CPR guidelines by experts, for everyone Less than 6% of dogs and cats that experience cardiopulmonary arrest (CPA) survive to hospital discharge, while the survival rate in people is over 20%. Until the advent of evidence-based guidelines and standardized training in human medicine, survival rates in people were similar to animals. No such standardized guidelines or training exist in veterinary medicine, which has led to extreme variability in the approach to cardiopulmonary resuscitation (CPR) and has likely contributed to the poor outcomes in dogs and cats with CPA. The Reassessment Campaign on Veterinary Resuscitation (RECOVER) initiative, a collaborative project supported by the Veterinary Emergency and Critical Care Society (VECCS) and the American College of Veterinary Emergency and Critical Care (ACVECC) involving over 100 board-certified veterinary specialists from around the world, has spent the last 18 months addressing this problem. These volunteers systematically reviewed the experimental and clinical evidence in cardiopulmonary resuscitation (CPR) research and devised a series of evidence-based, consensus CPR guidelines for dogs and cats. This project represents a unique undertaking in veterinary medicine, and will serve as a model for future development of true evidence-based clinical guidelines for many important diseases and conditions of animals. The results of this massive undertaking will be published in a special issue of the Journal of Veterinary Emergency and Critical Care in June of 2012 which is now available online. An overview of the methods used to develop the guidelines, a summary of the over 1000 scientific papers reviewed in each of five domains (Preparedness and Prevention, Basic Life Support, Advanced Life Support, Monitoring, and Post-Cardiac Arrest Care), and a full description of the new clinical CPR guidelines, including new algorithm and drug dosing charts is included in a special issue of the Journal of Veterinary Emergency and critical Care published in 2012. In addition, the authors have highlighted the level of evidence supporting each guideline and have identified important knowledge gaps in the literature that will serve as a roadmap for future veterinary CPR research. It is the hope of the RECOVER initiative participants that this body of work will serve as a foundation for the development of training tools for veterinarians, veterinary technicians, and pet owners, ultimately leading to improved outcomes in dogs and cats that experience CPA. 4. **[Definitions:]** Before we start, we need to remind ourselves of some definitions.  **Basic life support -- is based on ABC** A - Establishing a patent airway B - Providing positive pressure ventilation C - Generating circulation with chest compressions Advanced life support can be done once basic life support has been initiated, and comprises basic life support plus other interventions, such as drugs (reversal agents and arrest drugs such as atropine and adrenaline), electrical defibrillation and post-resuscitation support. 5. **[Which patients to resuscitate?:]** Studies looking at survival rates from CPR are variable, with an initial return of spontaneous circulation (ROSC) seen in around a third of patients. The outcome varies depending on the cause of the arrest, with anaesthetic related arrests having a better outcome than those related to an underlying disease. It's clear from looking at studies that patients having an arrest will fall into two groups; those with reversible causes that have arrested as a result of a problem which we can potentially resolve and improve their outcome (e.g. anaesthetic overdose, upper respiratory tract obstruction or hyperkalaemia), and those with irreversible causes which have arrested at the end point of their disease process (e.g. sepsis, SIRS, neoplasia or cardiac disease). As a result, sadly ROSC rates do not match the survival to discharge rates, as a lot of patients will have a further episode of arrest, complications as a result of their underlying disease, or be euthanised due to a very poor prognosis. Commonly given figures are that around 6% of animals suffering an episode of cardiac arrest make it to the point of discharge, although respiratory arrest alone has a much better outlook. The first question when we consider resuscitating a patient is whether we should or not. This depends on a number of factors which include: the owners wishes, the underlying disease process and what the expected outcome might be. If the animal has arrested as the end of its disease, then not attempting CPR in that patient is a very reasonable option and will prevent further suffering. In an ICU setting, discussing resuscitation codes ahead of time is very helpful. Making a do not resuscitate (DNR) order is stressful for owners, but it may help them appreciate the severity of the disease and give everyone a clear understanding of what to do if the patient deteriorates.  The second question is how aggressive should resuscitation be? Again, this depends on a number of factors, such as the number of staff present, equipment available (e.g. is a defibrillator present), the underlying disease process (for example should we consider open chest compressions in cases with poor chest compliance), the cause of the arrest and the owner's wishes. We will consider some of these points later.  6. **[Causes of Cardiopulmonary Arrest?:]** There are many possible causes of cardiopulmonary arrest (CPA). In human medicine the acronym of the 5 H's and the 5 T's is used -- this can be adapted to explain most of the causes of veterinary arrests. Vascular causes such as the thrombosis of the coronary and pulmonary arteries do occur in our patients but are much less common and harder to recognize than in man. **The 5 H\'s** **The 5 T\'s** --------------------- ------------------------------------ Hypovolaemia Tablets (overdose) Hypoxia Tamponade (pericardial) Hydrogen (acidosis) Tension Pneumothorax Hypo/Hyperkalaemia Thrombosis of the Coronary Artery Hypothermia Thrombosis of the Pulmonary artery In most cases, respiratory arrest will precede full CPA. Thus, timely intervention to assist and improve ventilation (e.g. administration of oxygen, drainage of pleural fluid or pneumothorax), may prevent the development of a full cardiac arrest.  7. **[Being Prepared:]** Successful CPCR relies on good preparation and teamwork. Ideally, there should be access to a well-stocked crash box, containing all the likely equipment required to run a successful resuscitation attempt. Team members should have practised the necessary techniques so that CPCR can be initiated as rapidly as possible. To perform effective CPCR, at least three team members are needed; one is responsible for ventilation, a second for chest compressions and a third for monitoring and administration of drugs. Because compressions are hard work, changing the operator every 2-3 minutes is essential. It is very difficult, if not impossible, to perform effective CPCR alone, however, the provision of chest compressions alone may prevent hypoxia in the short term, until help arrives. Where practical, on the discovery of arrest, the animal should be moved onto a suitable firm surface, in a well-lit and accessible area. Take a moment to consider, what you would put into a crash box if you were stocking it? 1. Endotracheal tubes (all sizes) 2. Laryngoscope with a variety of blades 3. Gauze bandage or tube tie to secure ET tubes 4. Ambu bag or easily accessible anaesthetic machine with appropriate circuit 5. Intravenous catheters and tape for securing  6. Heparinised saline  7. Needles and syringes 8. Urinary catheters (for airway suction and intra-tracheal drug administration) 9. Scalpel blades and sterile surgical kit 10. Adrenaline, atropine and lignocaine (with doses drawn up in labelled syringes) 11. Chart of commonly used drugs and doses 12. Fluids and giving sets 13. Other drugs to consider: Calcium gluconate, diazepam, mannitol, furosemide, dexamethasone 14. Advanced equipment: Tracheostomy tubes, interosseous catheters, ECG, defibrillator with internal and external paddles. **Crashbox** **[Airways]** This is the airway draw out of a crash box. It has a selection of ET tubes, a laryngoscope and separate syringes to make sure the tubes can be cuffed to provide positive pressure ventilation. There is also a selection of tracheostomy tubes in case of upper airway obstruction.  This is the airway drawer of a crash box In cases with upper airway obstruction, it may be hard to perform intubation.  There are a couple of options that might help:1 1. The first is to use a stylet inside the ET tube to help guide it into the larynx -- a dog urinary catheter works very well to do this  Afbeelding met binnen Automatisch gegenereerde beschrijving 2. The other option is to use a needle to perform a temporary tracheostomy. A 2ml syringe barrel can then be used to connect the needle to an oxygen supply which will help improve ventilation and can be followed by the placement of a tracheostomy tube following surgical cut down.  **[Drugs]** A drug dosage chart such as the one here from the RECOVER group is essential to know what dose (and volume) of drug to administer during an arrest situation. Having a laminated drug chart in the crash box or displayed in an obvious place really reduces the time taken to draw up medication.  Afbeelding met tafel Automatisch gegenereerde beschrijving An alternative is to have drugs such as adrenaline (epinephrine) and atropine kept drawn up in the crash-box in doses appropriate for 10kg patients. This avoids the need for calculation and preparation of these drugs during stressful situations and appropriate doses can be given rapidly. There are no fixed guidelines for the stability and sterility of drugs once drawn up into syringes, however replacing them every 2-4 weeks is recommended.  8. **[Routes of Drug Administration:]** Drugs can be given by a variety of routes and IV access is usually obtained after (or during) basic life support is put in place. 1. Central venous access offers the quickest access to the central circulation.  2. Peripheral venous access is adequate, as long as drugs are followed by a large volume flush to move the drug into the central circulation.  3. Intra-osseous uptake of drugs is very quick and placement of an interosseous needle is relatively straight forward. These can be easier to place than a peripheral catheter in a patient with poor perfusion. 4. Via the endotracheal tube: With the exception of bicarbonate, drugs can also be administered via a urinary catheter placed into the trachea through the endotracheal tube. Dosages of drugs should be doubled if this route is used and followed by large ventilation; this helps move the drug into the alveoli, allowing uptake into the pulmonary circulation. 9. **[Recognising an arrest?:]** For each of the following clinical signs, correctly identify which would make you suspicious that a cardiopulmonary arrest might be about to happen. Raises suspicion that an arrest might be about to happen: persistent mouth -- breathing, limb rigidity, obvious cyanosis, vomiting, absence of bleeding at surgical site, bizarre + exaggerated chest movements, sudden slowing of respiratory rate Does not raise suspicion that an arrest might about to happen: pyrexia, coughing, seizure activity **The first step in CPR is to recognise an arrest has taken place. Signs of CPA include:** 1. Absence of respiratory movements 2. of auscultable cardiac sounds or palpable pulses 3. Absence of consciousness It is important to realise that mucous membrane colour and capillary refill time are not reliable parameters and the presence/absence of a peripheral pulse can also be difficult to assess. Additionally, for arrests under anaesthesia, the ECG may remain normal for many minutes after death. It is recommended to use ABC to evaluate the collapsed, unresponsive patient and this should be completed within 15 seconds. The 15 second rule is the maximum amount of time spent assessing a patient prior to starting compressions using ABCs. **Airway** - Visually inspect (obstructions, masses, or fluid) - Internal and external palpation of the mouth, pharynx, larynx - Clear any fluid  **Breathing** - Visually inspect for movement (pluck hair from fur and hold in front of nostrils) - Feeling for air movement, auscultating the lungs **Circulation** - Palpation of the femoral and/or distal pulses and/or cardiac auscultation Once we have established the patient has suffered a CPA, we need to start CPR. To do this we need help (3-5 people), so shout realy loudly and move the patient to an area where CPR can be performed safely and effectively (a table or with bigger dogs dragging them out of the kennel). Where possible move them off any compressible mattresses or bedding as this will help improve the efficiency of chest compression.  10. **[Airways:]** The first priority is to establish a patent airway. In most situations, this is best achieved by the placement of a cuffed endotracheal tube. The tube is ideally placed under direct visualisation with a laryngoscope, as this helps reduce bradycardia induced by overstimulation of the epiglottis, and allows removal of any obstructive extraneous material. Correct endotracheal tube placement can be confirmed by visualisation, cervical palpation (i.e. the absence of a palpable tube in the oesophagus) and appropriate chest wall excursion with ventilation. A positive end-tidal carbon dioxide (ETCO~2~) measurement suggests good tube placement, however in a CPA, initial ETCO~2~ may be very low due to poor perfusion. If laryngeal visualisation is difficult, suction may be needed to clear excessive fluid from the oropharynx.  11. **[Breathing:]** Once an airway is established, providing positive pressure ventilation with 100% oxygen is the ideal. If oxygen supply is not readily available then room air (\~20% oxygen) will be adequate for CPR. An Ambu bag is a good way to provide positive pressure ventilation, however, any re-breathing bag attached to an anaesthetic circuit can be used, as long as it is purged of all anaesthetic gases before use. A ventilatory rate of 8-12 breaths/minute is appropriate in most patients, although smaller patients and those which were previously hypoxic may require a higher rate (12-20bpm). Positive pressure ventilation should produce a normal degree of chest excursion, with even inflation and relaxation over a 2 second period.  When providing ventilation, the chest wall should be seen to move, if it does not then the endotracheal tube may be blocked, incorrectly placed, or there may be thoracic disease stopping chest expansion (for example pleural space disease). Thoracic auscultation and/or thoracocentesis is required to rapidly determine and rectify the cause. Ventilation should not be over forceful or barotrauma of the lungs, haemorrhage and pneumothorax can occur. Overzealous (rapid) ventilation causing hypocapnia can reduce cerebral perfusion, or prolonged inspiratory ventilation times can increase intrathoracic pressure and thereby reduce venous return.  **Watch the video below about performing ventilation:** Play Video If the spontaneous ventilation resumes at this stage, a full CPA may have been avoided. In a respiratory arrest, acupuncture of the Jen Chung (GV26) point could be considered. Insertion and twisting of a 25-G hypodermic needle at bone depth in the midline of the nasal philtrum below the nares has been shown to increase respiratory rate. Reversal agents for drugs that cause apnoea may also be appropriate. Doxapram should be avoided as it decreases cerebral blood flow and leads to increased oxygen requirements. Which of the following statements are true? - Breaths should only be given with 100% oxygen (also 21%) - **ETCO~2~ may be low at the beginning of a CPR attempt due to poor perfusion** - Doxapram is safe to use in all patients it decreases cerebral blood flow and leads to increased oxygen requirements - **A respiratory rate of 8-12 bpm is suggested for most patients** - **Smaller patients may require faster breathing rates than larger ones** 12. **[Circulation:]** Generating circulation by effective chest compressions is an essential component of successful CPR and there are various techniques for different sized patients. Effective compressions are hard work as the chest wall should be compressed by at least 25-33%. Having several operators and switching out in 2 minute cycles (or sooner if you get tired), is a good way to make sure the compressions do not become inefficient. The aim is to provide a compression rate of 80-120/minute as this has been shown to be the most efficient rate to maintain effective perfusion. It's been shown that having a song in your head with a beat of 100bpm acts as a good mental metronome and this leads to more regular chest compressions than just thinking you can compress the chest at 100bpm.  The following songs have a beat of 100bpm and can be used to help correctly time the chest compressions: Staying Alive, Baby Shark, Nelly the Elephant and The Archers theme tune. **Baby Shark via YouYube**/ **Staying Alive via YouTube** [**[LISTEN]**](https://www.youtube.com/watch?v=I_izvAbhExY) It's really important that the compressions have an even duration of compression and decompression. During compression, the pressure generated moves blood forward, but during relaxation, the great vessels fill so that they are ready to generate blood flow when compressed again. Compressions aim to supply adequate perfusion to the heart, brain and lungs until the return of spontaneous circulation.  Recent guidelines have suggested that aggressive fluid therapy during CPCR should be avoided, as excessive fluid administration can result in decreased coronary and cerebral perfusion. This can be explained by the following equation: Aim to maintain:  **Myocardial Perfusion Pressure** = Aortic diastolic pressure - RA pressure & **Intracranial Perfusion Pressure** = MAP -- ICP In CPR, myocardial perfusion is the difference between a very low aortic diastolic pressure at the end of the chest compression and the right atrial pressure, which is effectively the central venous pressure (CVP). If we give fluids aggressively, we know that this increases CVP and will, therefore, reduce the difference between aortic diastolic pressure and right atrial pressure and lower myocardial perfusion. Therefore, fluid therapy should only be given if the animal was hypovolaemic prior to the CPA, for example, animals with severe blood loss. Interruptions to compressions should be avoided as it takes time to generate forward momentum within the circulation. Compressions should be continued during ventilation. Other interruptions, such as a change to operators, observing ECG changes, or palpating arterial pulses, should be minimised as much as possible and be as brief as needed. During chest compressions, the forward movement of blood and pressure is going to be very poor and as you can see in the graph, once compressions stop, perfusion pressure falls quickly and it takes some time to get this forward movement generated again.  13. **[Cardiac Pump:]** There are several methods for performing chest compressions. In cats and small dogs (\20kg), especially if closed-chest CPCR is not generating effective forward movement of blood. It should also be considered in animals with pleural space disease, pericardial effusion or chest wall trauma. To perform open-chest CPCR, a rapid left sided lateral thoracotomy is performed in the 6th intercostal space to allow direct compression of the heart, between two hands placed within the thoracic cavity. Cross clamping the aorta can also be considered to direct forward blood flow to the brain. In human emergency medicine, there is a relatively low rate of cardiac trauma and infection after open-chest CPCR, however, if successful it is recommended that the chest is lavaged thoroughly, samples collected for culture and that the incision is closed aseptically. Discussing with owners whether open chest CPCR is appropriate or desired in ill patients allows this invasive procedure to be executed rapidly should the need arise.  17. **[Basic Life Support:]** Performing basic life support will give your patient the best chance to initiate a return of spontaneous circulation. Once you have the patient intubated, are breathing for it and are administering efficient chest compressions, then you can move onto advanced life support. If there are enough people to help in the early phases, then you can start to do some of the more advanced parts sooner, but in the first instance, basic life support will give you patient the best chance. **Watch the video below for a demonstration of  the basic life support technique.**  18. **[Advanced Life Support:]** Once basic life support is in place, advanced life support can be considered. **These steps include:** 1. Gaining intravenous access 2. Reversing any anaesthetic drugs 3. Placing an ECG 4. Giving drugs 5. Considering defibrillation 6. Giving IVFT if hypovolaemic  7. Using advanced monitoring 8. Considering post CPA treatment **Administer Reversal Agents ** If the patient has had an anaesthetic agent or sedative prior to the CPA, then a reversal agent should be considered.  Match the reversal agent to the relevant drug. Only naloxone has been evaluated for use in patients in CPA. Although evidence of a beneficial effect is limited, in cases of opioid toxicity, naloxone should be used during CPR. Although no specific studies have evaluated the use of other reversal agents, in dogs and cats that have received reversible anaesthetic/sedative medication, administering reversal agents during CPR may be considered.  **Common Arrest Rhythms** Once effective basic life support is established, more advanced and specific treatment, such as drugs and defibrillation can be considered to restore spontaneous circulation or to correct the underlying cause of the CPCR. If possible, an ECG should be placed as soon as possible after CPA, as it will allow identification of the underlying arrest rhythm and dictate drug therapy. **In small animals the most common arrest rhythms are:** - 1 1. **Asystole **-- most commonly seen in traumatised, hypoxic or anaesthetised patients. Carries a poor prognosis, but should be treated with aggressive CPCR and adrenaline. 2. **Pulseless electrical activity (PEA, previously known as electromechanical dissociation or EMD)** - PEA occurs when the ECG records normal electrical activity within the heart but there is little or no myocardial contractility. Anaesthetic overdose, acute hypoxia, acidosis, toxicity and cardiogenic shock are potential causes of PEA. Again, treatment with CPCR and adrenaline is recommended.     3. **Ventricular fibrillation - **Ventricular fibrillation is much less common as an arrest rhythm in small animals in comparison to humans, (in whom it occurs in about two-thirds of arrests). Ventricular fibrillation leads to random activity within the ventricles, thus producing no propulsive ventricular contraction. Ventricular fibrillation can only be distinguished from PEA by observation of an ECG.  Effective treatment requires defibrillation, which is best applied electrically via a defibrillator. This requires specialist training and equipment which is not readily available. Alternatively, mechanical defibrillation in the form of a forceful precordial thump over the heart base may allow the myocardium to return to a perfusing rhythm.  **Vasopressors** Adrenaline has effects on α-adrenergic receptors, (causing peripheral vasoconstriction and increasing blood pressure and blood flow to the head), and β-adrenergic receptors (increasing heart rate and contractility). Adrenaline is recommended for the initial treatment of asystole and PEA. In human medicine, there is controversy as to whether high or low dose adrenaline is superior. High dose adrenaline is associated with better short term outcomes, however, it increases myocardial oxygen demand which is detrimental when oxygen delivery is limited during and immediately after a CPA. In general, low dose adrenaline is suggested in the first instance, moving to high doses if there is a lack of response.  **Vagolytic Therapy** Atropine is a vagolytic drug which is useful to treat sinus bradycardia, 3rd degree AV block or increased vagal tone. Cautious dosing is advised, as it can cause a marked rebound tachycardia which will increase myocardial oxygen demand.   Many other drugs are useful in specific circumstances, such as lidocaine for the management of post-resuscitation ventricular tachycardia, sodium bicarbonate for severe metabolic acidosis and specific anaesthetic antagonists. Once heart rate and rhythm and a peripheral pulse have been restored, arterial blood flow may be maintained with dopamine.   **Monitoring Resuscitation** During CPCR, one team member is responsible for monitoring the effectiveness of the resuscitation attempt and for the return of spontaneous circulation. ECG monitoring should always be used if available. Palpation of the femoral pulse is a routine technique for monitoring forward blood flow but can be misleading as compression can generate venous pulses due to backflow of blood in the caudal vena cava. If available, a Doppler blood pressure probe placed on the lubricated surface of the eye can detect retinal blood flow. If retinal blood flow is present, it suggests adequate cerebral perfusion should be present. Monitoring should also continue for other signs of effective circulation, such as an improvement in mucous membrane colour, a reduction in capillary refill time and a reduction in pupil size.  The use of pulse oximetry should be avoided, as pulsatile blood flow is usually inadequate during CPCR. Measurement of ETCO~2~ with a capnograph provides useful information. A progressive increase in ETCO~2~ reflects the success of ventilation in moving CO~2 ~from peripheral tissues to the lungs and out of the body in the course of the resuscitation attempt. There is no consensus as to ETCO~2~ values for endpoints for resuscitation in veterinary medicine, however, documenting a reliable trace is a good indicator of successful perfusion. Ventilation should not cease immediately on return of spontaneous respiration, but continue as required until the patient regains consciousness.  **Post Resuscitation** If the patient is successfully resuscitated, then close monitoring is essential, as many animals will suffer second arrests. Particular care should be paid to oxygenation, ventilation, blood pressure and perfusion status, to avoid complications such as pulmonary oedema, renal failure and disseminated intravascular coagulation. It is very common for neurological abnormalities, such as blindness and proprioceptive deficits to be present after CPA. These may not become obvious immediately, but may develop over 12 hours and usually resolve after 48-72 hours. Glucocorticoids should not be administered to these patients as they may worsen the outcome by causing hyperglycaemia.  19. **[Summary:]** Hopefully, you now feel prepared for any crash CPA situation that might happen! The key is to think logically and not to panic. Get help, as the more people there are to help (and provide moral support) the easier it is. Start with the basics and think ABC to allow good basic life support before considering drugs and more advanced life support options. If you are lucky enough to get the patient back, careful monitoring and intensive post resuscitation support gives the patient the best possible chance to get to discharge. Lastly, if your patient isn't so lucky, it can be hard to explain this to owners who watch CPR on the TV and get an unrealistic impression of how hard it is. It would make very boring TV programmes if everyone undergoing CPR died, so there is an increased survival documented compared to the real world. The article below is my favourite study from NEJM, which documents a 67% survival to discharge, which is much higher (about 6 times) than the actual discharge rate at the time.  **Cardiopulmonary Resuscitation on Television --- Miracles and Misinformation ** 20. **[Completion of Online Learning:]** You have now completed Week Three, Lesson Three of Emergency Medicine and Critical Care. **To recap the learning objectives, you should now be able to:** 1. Explain the causes of cardiopulmonary arrest and which patients might make the best candidates for resuscitation; 2. Recall the components of basic life support (ABC); 3. Outline what equipment and training might be helpful to manage arrest situations; 4. Consider the options for more advanced life support; 5. Reflect on the likely outcomes of cardiopulmonary resuscitation.