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 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.)

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.

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.

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).

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).

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.

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.

The inhalation of gases, smoke or toxic vapours can rapidly cause death. Victims need to be removed quickly from the source of the fumes, but the rescuer(s) may need protective equipment in order to do this. Attempts by inexperienced, unprotected persons may well result in further casualties, so emergency services should be called promptly. CARBON MONOXIDE (CO) is particularly dangerous because it has neither taste nor smell and can speedily overcome anyone exposed to the gas, especially in a confined space such as a kitchen or garage. Victims need to be taken into the open air and their breathing quickly restored with artificial respiration (see cardiac/respiratory arrest, above). If oxygen is available and there is no risk of fire, it can be given.

The number of substances with which people are poisoned, either deliberately or accidentally, is too great to list individually. This section will merely cover some basic principles to follow on discovering a person who has been poisoned.

If the person is unconscious, he or she should be nursed in the coma position (see cardiac/respiratory arrest in this appendix). Vomiting should never be induced at home except under medical supervision. If corrosive substances have been ingested, then water or milk should be drunk to dilute the effects on the oesophagus and stomach, and any remaining on the skin should be washed away with copious volumes of water. The container from which the tablets or other substance came should be taken to hospital with the patient to help medical staff correctly identify the poison. Likewise if it is a plant, a leaf or a berry. (See also POISONS.)

A major SEIZURE or fit (see EPILEPSY) consists of two phases: the tonic phase when the person may let out a cry, falls to the ground and appears rigid; and the clonic phase when he or she shakes. At the end of the fit there is usually a period of unconsciousness. The most important task in looking after people undergoing a fit is to prevent them from doing any damage to themselves. Any objects which might cause harm, particularly hot food and liquids, should be moved out of their way, but there is no need to try to move the person themselves unless they are in danger (it may, however, be necessary to roll them on to their side to prevent asphyxiation). No attempt should be made to protect the tongue, and a finger should not be inserted in the mouth to straighten the tongue. Clothing around the patient's neck should be loosened and, if possible, a pillow placed under the neck. At the end of the fit, when the person is unconscious, he or she should be placed in the coma or recovery position (see cardiac/respiratory arrest, above).