In the Midst of Life

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 effectivecombination 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 lungdisease, 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