Black's Medical Dictionary

Harvey Marcovitch

• Publisher: Bloomsbury Information
• Year: 2017
• ISBN:
  9781472943064
• Edition: 43
• Topic: Medicina
• Subtopic: Teoria, pratica e riferimenti medici

Black's Medical Dictionary has been the best-selling medical dictionary for over 100 years. It is invaluable as a home reference and for all who need clear explanation of medical terms: nurses, health care professionals and students, health service management, actuaries, lawyers and journalists. It contains over 5000 definitions and descriptions of medical terms and concepts with over 1000 diagrams, drawings and colour illustrations. It also provides helpful appendices on common medical tests and procedures, travel and health, measurements in medicine, health economics, complementary and alternative medicine, and an address list of support professional organisations.

APPENDIX 1: BASIC FIRST AID

This appendix is designed to cover the basic principles involved in the immediate treatment of some common emergencies. It is not comprehensive, and anyone wishing to become proficient at first aid should attend a course run by a reputable organisation such as the British Red Cross, St John Ambulance, and the St Andrew’s Ambulance Association. Knowledge of first aid can be of great practical value whether at home, at work or when travelling. On occasions its prompt application may save someone’s life or lessen the potential harm of an accident.

First-aid treatment in an emergency is intended:

•to preserve life and stop the victim’s condition from deteriorating.

•to help recovery and save the victim from further harm.

•to make the casualty as comfortable as possible and reassure him/her and the family.

•to assess the events surrounding the illness or accident so that relevant facts can be given to a doctor, nurse or paramedical staff.

No ill or badly injured person should be moved without skilled assistance – especially if a neck or spinal injury is suspected – unless the individual’s life is in immediate danger from the surroundings (e.g. a fire). He or she should be kept warm; constricting clothing should be loosened; and a clear airway should be established, with any false teeth removed.

Bleeding This may occur from arteries, veins or capillary beds. The former is easily recognised as the blood tends to spurt from the wound at the same rate as the pulse; with the latter two types the blood tends to flow from the wound. Minor bleeding is usually treated in the home by the application of bandages, etc. However, the basic principles of treatment for major haemorrhages may be applied. Pressure should be applied to the bleeding point, via gauze or a clean piece of cloth if available, firmly enough to stop the flow of blood. With the pressure applied, the wound should be raised above the level of the heart. The patient should then be transferred to a place where medical care is available. If the loss of blood is severe enough for the victim to have become shocked (see SHOCK), he or she should be laid flat with the legs raised, if possible. (See also HAEMORRHAGE.)

Burns and scalds Burns can be caused by dry heat, severe cold, corrosive materials, radiation (including rays from the sun) and friction (such as results from a body sliding along a road surface after a motorcycle accident). Scalds are caused by hot fluids or steam. Burns and scalds may be associated with other injuries caused, say, by an escape from a burning building, a road traffic accident or an explosion: casualties should therefore be examined for other injuries. Most burns and scalds affect the skin, and the area(s) and site(s) of skin damaged are important in assessing a victim’s condition. Muscles and other tissues may be damaged by burns, and inhalation of smoke or fumes may damage the linings of the mouth, throat and lungs. SHOCK, sometimes severe, is common – the result of pain and loss of body fluids. All but the most minor burns should be seen by a doctor, as it is difficult to assess the severity of the burn immediately after it occurs. If the person or his or her clothing is actually on fire, then the first move must be to smother the flames – by covering them with a blanket or coat, for example – and ‘patting out’ the flames without sustaining burns yourself. Many burns, however, are caused by hot liquids, hot gases, flashes from explosions or contact with a very hot object so that the person is not actually on fire. The treatment for all these burns is the same – to remove any clothing over the affected area, if possible, and to put the affected area under cold running water until the pain has stopped or skilled help has arrived (the cold water should be applied for several minutes, as cooling of the tissues, particularly the deeper layers of the skin, will limit the extent of the burn). The burn should be left exposed or covered with a piece of clean wet linen (e.g. a pillowcase), for the transfer to hospital. No lotions or potions should be applied to the burn until it has been seen by a paramedic, doctor or a nurse. (See also main dictionary entry for BURNS AND SCALDS.)

Choking Severe life-threatening CHOKING occurs when a piece of food or a foreign object becomes lodged in the LARYNX or TRACHEA causing obstruction. The person may cough, gag, or wheeze and will become cyanosed (blue) as he or she fights to take a breath. Infants or small children should be held along the arm, head down, and several gentle blows with the flat of the hand should be delivered to the back between the shoulder-blades: this will usually dislodge the foreign body. In older children or adults the ‘Heimlich Manoeuvre’ should be employed. Stand behind the victim with your arms wrapped around the waist. Make a fist with one hand, with the thumb placed at a point half-way between the victim’s navel and the bottom of the breastbone. Grasp the fist with your other hand and give a quick inward and upward thrust. This may be repeated several times if necessary. Alternatively, if the person is unconscious, he or she should be placed on the back, face up, and the same thrust performed with the heel of the hand whilst kneeling astride the hips. If a choking person is alone, he or she can perform the manoeuvre by placing a fist in the correct position and delivering the thrust by pressing it against a firm surface.

Cardiac/respiratory arrest The measures described here are basic life-support procedures – they can be performed if necessary without any equipment. Before commencing cardiopulmonary resuscitation on a person who has collapsed, it is essential to establish that it is in fact required. Performing artificial ventilation and cardiac massage on a person who is breathing and whose heart is still beating can be dangerous. The person’s chest and abdomen should be observed for respiratory movement and the PULSE should be checked either at the neck or groin or by feeling directly over the heart.

The technique for simple resuscitation may be remembered by means of the mnemonic ‘ABC’ (Airway, Breathing and Circulation). The aim of basic resuscitation is to maintain the flow of oxygenated blood to vital organs until the person’s heartbeat and breathing can be restarted, if that is possible.

AIRWAY If the airway is obstructed, no air can enter the lungs; therefore the mouth should be checked for foreign bodies, which can be removed by hooking them out with an index finger. False teeth should be removed. To prevent the tongue from obstructing breathing, the jaw should be pulled forwards (using a finger behind the angle of the chin) and the head extended on the neck so that the person looks as if he or she is ‘sniffing the morning air’.

Care must be taken if there is any suspicion of neck injury.

BREATHING If clearing the airway does not allow breathing to recommence, then artificial ventilation of the lungs must be started. Mouth-to-mouth ventilation, using the rescuer’s expired air to inflate the victim’s lungs, is probably the easiest and most satisfactory technique. The victim is positioned as described above. The rescuer uses one hand to obstruct the nose and steady the head, and the other to pull the jaw forwards and open the mouth. The rescuer then places his or her mouth completely over that of the victim and blows out so as to inflate the victim’s lungs, starting with two slow breaths to reinflate the lungs. It is important to observe the victim’s chest rise and fall normally before commencing the next breath. If the chest does not rise, or if there is marked resistance to the inflating breath, then the airway is probably obstructed and the head should be repositioned.

CIRCULATION Ventilating the lungs without any blood circulating will not provide oxygenated blood to vital organs. Therefore, if there is no pulse or heartbeat, cardiac massage should be started to produce this circulation. The person performing cardiac massage – who should preferably have been trained in the technique – should kneel beside the victim with the heel of one hand over the lower two-thirds of the breastbone and the other hand placed on top. Downward pressure is applied, keeping the arms straight with the elbows locked, so as to depress the breastbone 5–6 cm. Pressure is released to allow return to the previous position. The rate of compressions should be 100–120 per minute. If there are two rescuers, then the person performing cardiac massage should stop after every 30 compressions to allow the other to perform two cycles of artificial ventilation. As a single untrained rescuer, it is better to concentrate on compressions until help arrives.

Once spontaneous ventilation and cardiac output have returned, the patient should be placed in the recovery, or coma, position. This consists of rolling the person on to his or her side, with the lower arm and leg straight and in line with the body. The upper arm and leg are flexed and brought forwards to prevent the patient from rolling on to his or her front.

Drowning Around 500 people die from drowning each year in Britain, and an unknown number survive a near-drowning. About one-fifth of drownings occur in salt water. Wet drowning (when water is aspirated into the lungs) occurs in 85 per cent of cases; the remaining 15 per cent develop spasm of the larynx so that, although they may die from ASPHYXIA, no water enters the lungs.

There has been some controversy about what type of water carries the worst prognosis, but it is now thought that salt and fresh water are equally bad. The effect of salt water is to draw fluid into the alveoli (see ALVEOLUS) from the blood with resulting damage to the lung because of PULMONARY OEDEMA and HYPOXIA. Fresh water washes out pulmonary SURFACTANT (causing the lung to collapse, so leading to hypoxia and is absorbed into the blood stream causing volume overload and disturbances of ‘Electrolytes’, for example a very low sodium level which brings its own complications. Both types may result in ACIDOSIS and circulatory collapse, and may be complicated by HYPOTHERMIA and trauma (which may indeed have precipitated the drowning).

Treatment Cardiopulmonary resuscitation (see cardiac/respiratory arrest in this appendix) should be started as soon as possible and the patient transferred to hospital. This should include people who recover consciousness fairly quickly, as pulmonary oedema may develop over the next few hours. If the patient is hypothermic (see HYPOTHERMIA), resuscitation should continue until he or she has been warmed to normal body temperature. Patients may require admission to an intensive care unit for artificial ventilation, circulatory support and correction of electrolyte imbalance and acidosis.

Electrocution People may be electrocuted when they touch an object which is live so that a current passes through them to earth. A lightning strike has a similar effect. The severity of the outcome depends upon the frequency and amplitude of the current which flows through them. Below 2milliamps (mA) there is only a feeling of strong tingling; fifteen–one hundred mA will produce contraction in the muscles near the point of contact, which makes letting go of the object impossible; 50mA–2A is the threshold for producing VENTRICULAR FIBRILLATION. (These thresholds are for the mains electricity supply, which in Britain has a frequency of 50Hz – one that is particularly liable to induce ventricular fibrillation.) Thus, electrocution can cause burns (see burns and scalds, above) to the tissues at the sites where the current enters and leaves the body, and may also induce ventricular fibrillation. If a person is seen being electrocuted, no attempt should be made to touch the victim until the power supply is turned off, as the helper may also be electrocuted. If the switch or mains supply cannot be found, then the victim should be knocked away from the power source using a non-conducting object such as wood. Burns should be treated as described above and, if the patient has developed ventricular fibrillation (when it may be difficult to feel a pulse and there is pallor due to circulatory collapse) – then cardiopulmonary resuscitation should be started (see cardiac/respiratory arrest in this appendix).

Foreign bodies Unwanted objects may enter the eyes, ears, nose, mouth, OESOPHAGUS lungs or wounds. Foreign bodies in wounds, lungs, oesophagus and stomach should be treated by a clinician; unskilled attempts to remove them, unless breathing is obstructed, when a ‘Heimlich Manoeuvre’ may be needed, may harm the patient.

EYES Dust, eyelashes and displaced contact lenses that have not penetrated the tissue of the eye are usually easily removed by washing with clean water, preferably using an eyebath. If the foreign body is stuck to or has penetrated the surface of the eye, the eye should be covered with a clean pad and medical attention obtained.

EARS AND NOSE Do not attempt to remove the foreign body: obtain medical attention.

Heatstroke This occurs when the body becomes dangerously overheated because of a high fever or prolonged exposure to heat – for example, being out in the hot sun or working in a hot environment (e.g. near a furnace). Heatstroke may suddenly occur or manifest itself by the victim’s feeling uncomfortable, ill or confused. Remove the casualty from the heat source and lower the body TEMPERATURE by removing clothing and wrapping the patient in a cold wet sheet or towel, fanning him or her and sponging with cold water. Obtain urgent medical attention.

Inhalation of fumes The inhalation of gases, smoke or toxic vapou...