In the Midst of Life (47 page)

Jennifer Worth, April 2011

‘Lord, grant us a quiet night and a perfect end,

so that we who are wearied by the changes and chances

of this fleeting world

may rest upon Thy eternal changelessness’

—
The Anglican office of Compline from the Book of Common Worship

Appendix I: Medical
aspects of cardio-pulmonary resuscitation,
David Hackett

Appendix II: The Paramedic’s Tale,
Louise Massen

Appendix III: Should patients at the end of life be given the option of receiving CPR?,
Madeline Bass

Appendix IV: Principles of Palliative Care,

Madeline Bass

Medical
aspects of cardio-pulmonary resuscitation DavidHackett, MD, FRCP, FESC.

Consultant Cardiologist, West Hertfordshire Hospitals NHS Trust, and Imperial College Healthcare NHS Trust; former Chairman of the Resuscitation Committee, West Hertfordshire Hospitals NHS Trust; and former Vice-President of the British Cardiovascular Society.

During the Second World War and in the Korean War the severe injuries inflicted led to surgeons having to extract bullets and shrapnel from many locations in the body including the heart. Previous medical teaching had assumed that any cardiac surgery would be fatal, but many foreign bodies were successfully extracted from the heart without mishap. This led to the dawn of modern heart surgery, and the recognition that many serious heart conditions could be treated. Doctors observed that ventricular fibrillation, a fatal abnormality in cardiac rhythm, could occur in certain circumstances such as during induction of anaesthesia or in the early stages of heart attacks in hearts that were otherwise healthy, ‘hearts that were too good to die’. It was also known that accidental electrocution could induce ventricular fibrillation, and that powerful electric shocks could reverse it. In 1947, the first successful internal defibrillation was performed during an open chest surgical procedure. The first successful external defibrillation was performed in 1955, and in the early 1960s portable defibrillators were developed. In 1967 mobile coronary care units were introduced in Belfast, with successful out-of-hospital defibrillation in patients with acute heart attacks. These developments led to the concept of Emergency Medical Services, to bring medical care to resuscitate the victim at the scene, rather than ‘scoop and run’ to the hospital.

It
has been known since the late 19th century that open chest cardiac massage could maintain an effective circulation. Closed chest cardiac massage by compressing the front of the chest against the vertebral spine resulting in compression of the heart and ejection of blood into the arteries was rediscovered in 1960. Mouth-to-mouth ventilation, often used to initiate breathing in a newborn, was shown to maintain oxygenation, and resulted in a switch from more cumbersome manual ventilation techniques. The combination of chest compression and mouth-to-mouth ventilation, or cardio-pulmonary resuscitation, became known as basic life support; this could maintain life for a short time until defibrillation or another definitive procedure was performed.

Recent developments in cardio-pulmonary resuscitation

It has long been recognised that the key elements of survival from cardio-respiratory arrest are early recognition and prompt call for help, early cardio-pulmonary resuscitation, early defibrillation and early advanced medical care. Recent developments to aid out-of-hospital resuscitation include Automated External Defibrillators (AED), which use electrode pads attached to the chest to diagnose the heart rhythm. If ventricular fibrillation is confirmed then both screen display and verbal advice is given to press a button and deliver a defibrillating electric shock. These devices have led to first responder defibrillation, public access defibrillation and home defibrillation. If an ambulance has been called, the dispatcher can provide telephone instructions to direct bystanders to initiate resuscitation while awaiting the arrival of the emergency medical services.

Modern cardio-pulmonary resuscitation – A B C

The Resuscitation Council (UK)
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publishes various guidelines for cardio-pulmonary resuscitation, which are internationally accepted. If someone collapses or is found to be unresponsive, the
standard approach follows the pattern Airway, Breathing, Circulation or A B C. Detailed guidance and flow-chart posters can be found in various publications available from the Resuscitation Council website.
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On discovering a collapsed or unresponsive person, the bystander or professional should call for immediate professional help if in hospital, or telephone the national emergency number if out of hospital. Resuscitation is a team effort, and cannot be performed effectively by an individual.

The first action is to ensure the airway is clear of obstruction from the tongue, mucus or a foreign body. If the circulation is working adequately, the subject is placed in the lateral recumbent or recovery position on their side, which prevents the tongue from obstructing the airway. If there is cardiac arrest, and the patient should remain lying on their back to allow resuscitation, a short plastic tube known as a Laryngeal Mask Airway (LMA) or other oral airway such as an oro-pharyngeal or Guedel airway is inserted into the throat to keep the upper airway open. In unconscious patients with ongoing cardio-pulmonary resuscitation, a longer tube called an endo-tracheal tube can be inserted from the mouth directly into the windpipe to allow direct ventilation with a manual bag or ventilator; insertion of an endo-tracheal tube is a highly specialised skill usually undertaken by trained paramedical staff or anaesthesiologists.

The second action is to ensure that the subject is breathing. If there is no spontaneous breathing, then mouth-to-mouth ventilation should be commenced, although with this technique there is a risk of infections being transmitted.

The third action is to ensure there is a circulation. If there is no effective circulation, then chest compressions should begin. The most effective circulation is achieved with chest compressions at a rate of about 100 times a minute, or just less than two per second. Ventilation can interfere with chest compressions as the lungs expand, so it has been found that the most effective
combination is two ventilations for every thirty chest compressions.

Advanced life support

Advanced life support relates to the underlying causes of a cardiorespiratory arrest. If there is no circulation because the heart is in ventricular fibrillation, then only prompt defibrillation with an appropriate electric shock can restore the normal rhythm. If the heart is in an abnormal rhythm and going very fast, such as in ventricular tachycardia, then a defibrillating electric shock can also restore a normal rhythm. Various other treatments can help or restore normal circulation. For example, if during basic life support the circulation is inadequate because of a very slow pulse from heart block (when the electrical impulses that control the beating of the heart are disrupted), medications such as atropine or adrenaline can be given by intravenous injection to speed up the heart rate, and many modern defibrillators can perform external electrical stimulation, which can also increase and pace the heart rate. If blood pressure is inadequate because of a weakened heart, then medications such as adrenaline can be injected to stimulate the force of contraction of the heart thereby raising the blood pressure. Abnormally fast heart rhythm disorders can be treated with anti-arrhythmic drugs, such as amiodarone.

Results of cardio-pulmonary resuscitation

The results of resuscitation depend crucially on where the cardiopulmonary arrest has occurred, and the previous medical history. Resuscitation in hospital should be, and usually is, prompt and more likely to be effective, whereas outside hospital there may be a delay and therefore the outcome is less likely to be as good. Secondly, if there is no previous medical history of cardiopulmonary disorder, and there is good cardiac and lung function, then the outcome can be good; in this circumstance, successful resuscitation can usually result in the patient returning to normal activities and having a normal life expectancy. On the other hand, if there is a history of advanced heart failure or end-stage lung
disease, then the outcome is often poor; in this scenario, resuscitation can be technically successful in the very short term, but is unlikely to result in the patient surviving to discharge from hospital. The success rates reported as regards resuscitation from cardiorespiratory arrest will also depend crucially on the selection of patients. If every patient who is dying is resuscitated, then the success rate to survival at discharge from hospital will be low. Conversely, if resuscitation is not attempted on all those patients who are near death from an untreatable condition, and in all others who are considered medically inappropriate to be resuscitated, then the success rate will be much higher.

Results of cardio-pulmonary resuscitation in hospital

An audit of 1,368 cardiac arrests occurring in forty-nine hospitals in the United Kingdom in 1997 showed that eighteen per cent of patients were discharged alive, and of these eighty-two per cent were still alive six months later.
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In thirty-one per cent of these patients there was a treatable cardiac rhythm disorder such as ventricular fibrillation or ventricular tachycardia, and within this group forty-two per cent were discharged alive. If the cause of the cardiac arrest was not an easily treatable cardiac rhythm abnormality, then only six per cent were discharged alive. In this audit, factors associated with an improved chance of survival included an easily treatable cardiac arrhythmia as the cause of the arrest, a prompt return of the circulation in response to cardio-pulmonary resuscitation, and the age of the patient, with those under seventy being more likely to survive. The Resuscitation Council (UK) and The Intensive Care National Audit & Research Centre (ICNARC) are collaborating to develop a national database regarding cardio-pulmonary arrests that take place in hospital† to enable analysis of the frequency of, and outcome from, resuscitation
in the United Kingdom. This should result in more consistent reporting and a better understanding of what might result in improved success rates.

The statistical likelihood of success in cardio-pulmonary resuscitation is not reflected in popular television dramas! A study of ninety-seven episodes of television medical dramas in the United States of America in 1994-1995 analysed sixty occurrences of cardio-pulmonary arrest; sixty-five per cent of these arrests occurred in children, teenagers, or young adults and sixty-seven per cent appear to have survived to hospital discharge.
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Such rates are significantly higher than even the most optimistic survival rates in the medical literature and the portrayal of cardio-pulmonary resuscitation on television may lead the viewing public to have an unrealistic impression of the procedure, and its chances of success.

Results of resuscitation for out-of-hospital arrest

In 2004 the Ontario Pre-hospital Advanced Life Support Study of 5,638 patients who had had an out-of-hospital cardiac arrest reported that only five per cent survived to discharge from hospital.f There did not seem to be any trend towards improved survival over time with the introduction of community-based initiatives. The registry of cardiac arrests in the community of Goteborg in Sweden reported that of 5,505 patients who had suffered an out-of-hospital cardiac arrest between 1980 and 2000, between eight and nine per cent of these survived to hospital discharge.
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Again there was no trend towards improvement in
survival rates over the time period of the study. A systematic review and meta-analysis published in 2010 detailing seventy-nine studies of out-of-hospital cardiac arrests involving 142,740 patients reported that twenty-four per cent reached hospital alive, but the rate of survival to hospital discharge was 7.6 per cent overall and this survival rate has remained unchanged over the last thirty years.
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Again survival ratio depended on many of the same factors as in-hospital cases i.e. the speed of response, whether the patient received cardio-pulmonary resuscitation from a bystander, if the cardiac rhythm abnormality was easily treatable, or if there was an early return of spontaneous circulation.

In 2004, a study of nearly 1,000 communities in twenty-four North American Regions reported that survival to hospital discharge was twenty-three per cent in those areas equipped with staff trained in using Automated External Defibrillators (AEDs), whereas survival was fourteen per cent in those areas without.
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Increasingly, cardiac arrests which occur out-of-hospital are also being automatically treated by a special type of implanted pacemaker known as an Internal Cardiac Defibrillator (ICD). These have been available for more than ten years, and have been implanted in those people at the highest risk of developing lethal cardiac rhythm disorders. When implanted, the devices promptly diagnose and treat almost all lethal cardiac rhythm disorders within a few seconds, using an internal electric defibrillator shock. The widespread use of these devices might paradoxically skew the statistics regarding survival rates, as those not fitted with the device are likely to have less easily treatable conditions and are therefore less likely to be successfully resuscitated following a cardiac arrest.