In the Midst of Life
Page 35
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)* 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.* 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. *
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.* 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.† 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.* 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.† 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.
In 2006 the Termination of Resuscitation Study investigators in Ontario reported on the development of a theoretical rule which would predict a low chance of survival from out-of-hospital cardiac arrest to hospital discharge.* Where there was no return of spontaneous circulation, no defibrillation shocks had been administered, and the arrest was not witnessed by the emergency services, the rule recommended termination of resuscitation. Of 776 patients with cardiac arrest for whom the rule recommended termination of resuscitation, only four survived (0.5 per cent) to hospital discharge. If the additional criteria of an emergency services response interval of more than eight minutes, were included, together with the arrest not being witnessed by a bystander, then this rule would have proved 100 per cent accurate. These factors should not be used to avoid resuscitation in all such cases, and they should not be applied automatically or be allowed to over-ride clinical assessments. However, they can be very helpful in judging the value or futility of attempting resuscitation or continuing resuscitation of victims of an out-of-hospital cardiac arrest.
Many resuscitations on out-of-hospital cardiac arrest victims are inevitably delayed, and the consequence can be brain injury or damage from lack of circulation and oxygen. It is very difficult to predict the likelihood of recovery from acute brain injury at the time of the arrest, and some patients do make a full recovery.
There are specific circumstances when a full recovery can occur after a long delay, such as cases of electrocution, drowning, hypothermia, poisoning, or anaphylactic (allergic) shock. According to the Resuscitation Council, by three days after the onset of coma related to cardiac arrest, fifty per cent of patients have died.† The International Liaison Committee on Resuscitation consensus statement on ‘post cardiac arrest syndrome’ states that the most reliable predictor of a poor outcome (vegetative state or brain death) is the absence of a pupillary light response, corneal reflex, or motor response to painful stimuli at seventy-two hours.* On the basis of a systematic review of the literature, absent brain-stem reflexes or a low Glasgow Coma Scale motor score at seventy-two hours is reliable in predicting a poor outcome.
The frequency of prolonged coma or permanent brain disability after resuscitation will depend on the underlying cause of the cardio-pulmonary arrest, and the speed with which resuscitation was undertaken. A study published in 1997 of 464 out-of-hospital cardiac arrests in Bonn over three years reported that seventy-four patients (sixteen per cent) were discharged from hospital.f Thirty-four (7.3 per cent) were discharged alive without neurological deficit, twenty-two patients (4.7 per cent) were discharged with mild cerebral disability, nine (1.9 per cent) were discharged with severe residual cerebral disability, and a further nine (1.9 per cent) were in a persistent coma.
Should resuscitation always be attempted?
Traditionally it has been taught that resuscitation should always be attempted in people who have collapsed or in patients whose condition has suddenly deteriorated. The case of Karen Ann Quinlan in the United States of America changed medical practice and provided a focus to moral teaching about death and resuscitation.† In 1975, aged twenty-one years old, Karen Ann Quinlan was found unconscious and not breathing in bed shortly after consuming alcohol and drugs at a party. Resuscitation was performed, but she did not regain consciousness and remained in a persistent vegetative state for several months. Her family felt that she would never recover, and wanted to withdraw medical treatment including mechanical ventilation. Medical and hospital staff refused, on the basis that this would result in her intended and hastened death; the New Jersey Supreme Court ruled that the patient or their guardian had the right to determine their treatment, that medical staff had no rights independent of the patient, and that there was no obligation for medical staff to use extraordinary means to preserve life. This ruling confirmed the principle that medical treatment could be withdrawn, and resuscitation did not necessarily have to be attempted. Karen Ann Quinlan became known as the ‘right to die’ case.
The case also resulted in clarification of the legal status of ‘Do Not Attempt Resuscitation’ orders, and the concept of advanced directives with regard to possible future scenarios or treatments. It reaffirmed the idea that a patient always has the right to refuse extraordinary means of treatment, even if it will hasten their death. Furthermore, the Karen Ann Quinlan case resulted in the establishment of Ethics Committees in many hospitals to provide guidance to clinical staff in situations where patients do not consent to recommended treatments, or where unreasonable treatment is demanded.
Do Not Attempt Resuscitation
If a heart attack is treated promptly with defibrillation, and if other emergency treatment prevents damage to the heart, the patient can often return to a normal life and have a normal life expectancy. Clearly resuscitation in this circumstance would be worthwhile. On the other hand, if a patient with an advanced disease, such as terminal cancer or terminal lung failure, develops a sudden lethal cardiac rhythm disorder, successful resuscitation might result in limited benefit, such as survival for a few more days or weeks, potentially in the context of receiving intensive medical care. Many people would regard this second example of resuscitation as futile, or of limited value. Between these two examples are many shades of grey, and it is good medical practice to try to establish the likely value or futility of emergency resuscitation in each patient during acute illness or admission to hospital. It is also good medical practice to try to think about the likely value of undertaking emergency resuscitation if someone has a chronic progressive and untreatable condition.
A discussion about the benefits or futility of resuscitation can be difficult for someone if they have not considered the matter beforehand, particularly in the case of a newly diagnosed acute illness with limited treatment or with a grave prognosis. On the other hand, most people will want to talk, learn about and discuss their illness, especially when they are anxious or frightened. Talking about the prognosis should be a natural part of the discussion, although doctors often do not raise the subject of death if patients do not ask, and patients can be too uncertain or too frightened to ask. In my experience most people prefer quality of life to longevity but occasionally people will want to keep going for a specific reason even if they are very unwell, such as a family event l
ike the wedding of a son or daughter, the birth of a grandchild, or the completion of an important project.
Questions about resuscitation are not usually a simple yes or no decision. For example, most people who are not in an advanced terminal illness would want to be resuscitated from a simple cardiac rhythm disturbance or from transient difficulty in breathing due to infection, but often would not want prolonged intensive care with supportive treatment on an artificial ventilator or on kidney dialysis. Thus, any clinical discussion of resuscitation should include what types of resuscitation might be undertaken, and how far-reaching these directives might be. If the conclusion is that the person does not want to be resuscitated from their current illness, then this wish must be respected, and a note or statement made in their medical records to this effect. This statement should be as precise as possible, for example: ‘this person does not wish to be resuscitated from a cardio-respiratory arrest’. When patients have decided that they do not wish to be resuscitated, almost all hospitals have specific ‘Do Not Attempt Resuscitation’ (DNAR) forms for completion by an experienced doctor. There is a model DNAR form, as well as a model patient information leaflet, available on the Resuscitation Council website.* Most hospitals also have a resuscitation committee, which will agree local policies on the application of Do Not Attempt Resuscitation decisions, and audit the appropriateness of these orders.