How to treat injuries and save lives
E-Book, Englisch, 320 Seiten
Reihe: Elite Forces Handbook
ISBN: 978-1-909160-34-7
Verlag: Amber Books Ltd
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)
Key areas include breathing and circulation; healing wounds and stopping bleeding; dealing with head injuries and altitude sickness; treating burns and scalds; mending broken bones, damaged joints and torn muscles; and avoiding poisons and removing foreign objects from wounds. You will also learn how to respond to the problems caused by extremes of climate and temperature as well as how to cope with a range of illnesses, including appendicitis, diaorrhea and malaria.
With tips on injury avoidance and effecting a successful rescue, Survival First Aid ensures that you will be prepared for almost any medical emergency.
—Learn key techniques such as diagnostic procedures, resuscitation and treating shock.
—How to treat cuts and burns and deal with fractures and head injuries.
—How to recognize and avoid poisoning and remove foreign objects from wounds.
—How to cope with problems caused by temperature and climate, from hypothermia to heat stroke.
—Illustrated throughout with more than 150 specially drawn artworks.
—Features self-contained boxes on subjects as diverse as vaccinations, the effects of blood loss, fire safety and rescue codes.
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CHAPTER TWO
The human body & first aid
The human physique is both incredibly strong and intensely vulnerable. Life is sustained around the efficient functioning of three major body systems — circulatory, respiratory and nervous — and knowing how they work forms the basis of much of your emergency first aid treatment.
First aid is primarily about immediate and practical treatments, so advanced medical knowledge is not a pre-requisite. However, it is advantageous if the first aider comprehends the biological cornerstones of human life, for without an understanding of the body’s basic mechanisms, it is difficult to adapt treatments to meet unexpected developments in the illness or injury. Furthermore, without understanding or appreciating the reason for your actions, it can be more difficult to best apply yourself. We begin this chapter with a look at the three biological systems responsible for maintaining human life – the respiratory, circulatory, and nervous systems. From there, we move onto the fundamentals of first aid practice – diagnosis, assessment, and treatments when one or more of the major body systems is in acute failure. THE BODY’S SYSTEMS For a first aider, the essential principle to remember is that the oxygenation of the human body must be maintained at all times. All human tissue, but especially the major organs of the body, will quickly die if deprived of oxygen. It is the respiratory system’s job to draw air from the outside world, extract the oxygen and pass it into the blood. It is the job of the circulatory system to pump this blood around the body, and deliver oxygen to the body tissue while extracting waste products. Finally, the nervous system regulates the pace and efficiency of the whole process. When a first aider is faced with a casualty, their attention is (initially) totally given over to supporting the efficient function of all three systems if need be. For if any system fails, the result is hypoxia, or low levels of blood-borne oxygen. For example, a patient has an obstructed windpipe, then the respiratory system cannot draw air into the lungs, and the blood receives no new oxygen. This in turn means that the circulatory system does not contain enough oxygen in the blood to perform full-body oxygenation properly (a condition known as ischemia). Hypoxia, if not corrected, leads to infarction, the death of body tissue and organs. The brain is one of the most vulnerable organs to ischemic problems. Brain cells begin to die after only three minutes of deprivation, and if completely deprived of oxygen for more than five minutes, brain damage or brain death will almost certainly ensue. Consequently, in life-threatening emergencies the combating of ischemia is the first aider’s absolute priority. That involves the effective support of all three body systems, and we shall now look at each in more detail. The respiratory system Respiratory System The respiratory system consists of the mouth, nose, trachea, and lungs, and includes the network of pulmonary arteries that take oxygen from the lungs to the bloodstream. Breathing is controlled by the autonomic nervous system – the part of our brain and nerve network that regulates essential involuntary processes such as the heartbeat and body temperature. All breathing begins with inspiration (breathing in). This occurs when a network of muscles including the intercostal (between the ribs) muscles, the diaphragm, and muscle groups in the abdomen and neck work together to expand the chest cavity, creating a vacuum in the lungs which causes air to rush in via the nose or mouth. The air passes down the nose and trachea, a cartilage tube of between 10 and 12cm (4–4.75in) in an adult, which then subdivides into the bronchi (the first inverted Y-shape division is known as the stem bronchi). These subdivide continually to form a complete network of air passages in the lungs, and then subdivide even further into bronchioles, minute air passages which each terminate in an alveolus. The alveoli are millions of microscopic air sacs where the all-important transfer of oxygen into the blood and carbon dioxide out of the blood takes place. Thin-walled blood vessels known as capillaries (pulmonary capillaries in this case) surround each alveolus. Each capillary is tiny in diameter, and these receive oxygen into the blood stream through the wall of the alveoli, while passing back carbon dioxide and other wastes in the opposite direction. The wastes are vented by the last stage of breathing – expiration. Expiration is achieved when the rib muscles relax, return to position, and push the lung contents out of the nose or mouth. The average adult breathes at a rate of between 12 and 20 cycles per minute, depending on the level of exertion (greater oxygenation of the body is required to support intensive physical effort). The overall rate is controlled by the brain, which monitors the pH levels in the blood relative to the amount of carbon dioxide present – too much carbon dioxide and respiration is increased to aid its removal. The problems of the respiratory system will be explored in Chapter Three, but the following are the most common causes of respiratory failure: Airway obstruction – foreign body stuck in throat; swollen tongue or throat; strangulation; liquid in airpipe. Oxygen deprivation – smoke or gas inhalation; altitude sickness. Chest or lung injuries – crushed chest; broken ribs; punctured lung; pneumothorax; haemothorax; internal burns from inhaling super-heated air. Poisoning – carbon monoxide and other gases (poisoning can reduce the lungs ability to process oxygen). Head injury – damage to either the part of the brain or the nerves involved in the control of breathing. Secondary impairment – heart attack or shock resulting in the stoppage of breathing. Allergies and disease – asthma; anaphylactic shock; bronchitis; pneumonia. Hysterical/psychological – panic attack; sudden fear. The circulatory system Circulatory System The circulatory system, like the respiratory, works in a cycle. At the centre of the cycle is the human heart. This immensely durable muscle beats, rhythmically and regularly, to pump oxygenated blood throughout the network of blood vessels in the body. The heart beats at an average resting pace of about 60–90 beats per minute, climbing towards 190 during heavy exertion, when the body’s demand for oxygen is at its highest. The circulatory system starts its cycle when deoxygenated blood flows via the veins into the right chamber of the heart, the atrium, before being pumped out of the right pumping chamber, the ventricle, towards the lungs through the pulmonary artery. The blood is thus oxygenated and returns to the heart, where it collects in the left atrium and is pumped from the left ventricle through the aorta (the body’s largest artery) and around the rest of the body. The flow of blood around the body – veins taking blood to the heart and arteries taking it away – is aided by the contractions of the blood vessels themselves, which squeeze the blood on its passage. Between the small veins and arteries are thin-walled capillaries which allow nutrients and oxygen to be passed into body tissue, while also allowing waste products to be removed. The heart and the blood vessels form the essential circulatory system, but they are part of a much wider physiological organization dedicated to the efficient processing and use of blood. The spleen, liver, kidneys, and urinary system are all involved in the vital cleaning and regulation of blood content. Its involvement with complex major organs makes the circulatory system vulnerable to a significant catalogue of complaints and dangers, but from the first aider’s point of view, there is a basic range of injuries or illnesses to be aware of: Shock – not psychological shock, but the serious physiological shock resulting from blood or fluid loss from the bloodstream (see Chapter Three). Blood vessel damage or impairment – blood vessels can be damaged by external injury, or blocked by an internal blood clot. Either way, the effect is to stop the effective cycle of blood movement. Reduction in oxygenation – problems with the patient’s breathing eventually impact on the circulatory system as oxygen levels in the blood are lowered. Hypoxia can also result from various forms of anaemia (a reduction in the red blood cells’ quantities of haemoglobin, which carries oxygen around the body). Anaemia can occur for many reasons, from blood loss to genetically inherited illnesses (such as sickle-cell anaemia). Impairment of heart function – the arteries of the heart can go into sudden constriction or be obstructed (such as through a thrombosis), resulting in a heart attack. In this condition, the heart either stops beating or beats rapidly and ineffectively. Another common heart condition is angina, when the heart does not receive enough blood during times of exertion due to narrowed coronary arteries. Nervous System The nervous system consists of the central nervous...
