Pain as a human subjective symptom, since only the person suffering it can appreciate the intensity and quality of the pain, this features on many occasions, is a problem in assessing the intensity and the treatment to be followed by a health professional. (7)
Make a contextualization and definition of the pain, therefore goes to the International Association for the study of pain (IASP), which defines pain as "an emotional and sensory unpleasant experience associated with actual or potential tissue damage, or described in terms of such damage.", highlight the definition of McCaffery, developed in 1968, and has been a guide for physicians"anyone who is the person who experiences the pain that he says is, that exists when the person says it does.", as you can see the pain is a difficult concept to define, since it is not observable and varies according to the patient. The pain has gained great importance in recent decades due to the following: (14)
- It affects a large number of people, noted the developed countries, whose population increasingly has an average of higher age, which has a direct impact on the number of people affected by pain.
- Societies revolve around the maintenance and increase of the quality of life, therefore, the effective management of pain is essential to ensure quality of life until the death of the individual.
The value of an approach to pain management team is receiving greater recognition, the complexity of health care requires more and more health professionals work effectively in interdisciplinary teams to ensure the effectiveness and reliability of care.
2.2.1 CURRENT PAIN CONCEPT
-Pain is defined as today: "an experience sensory and emotional unpleasant, related to actual or potential damage of tissues, or described in terms of such damage"(19).
2.2.2. HISTORICAL ASPECTS
The pain has been a constant companion of human life from its origins, in this sense, there is evidence that humans have been distressed by this evil from time immemorial, as indicated by testimonies of all races.
Proof of this is in the Bible that mentions the pain since the expulsion of Adam and Eve from the "earthly paradise", condemned to suffer pain. This mention in the Bible, we can say two conclusions: (7)
- The pain is intrinsic to the human being and the life.
- The pain has been considered as a divine punishment, and therefore, something negative. This negative perception of pain has remained to the present day.
There will be a study of the history of pain chronologically organized:
Babylon: the science was part of the theology and the task of the doctor (priests) was placating the gods and keep them benevolent. Pain as a divine punishment without presenting a scientific treatment.
Ancient Egypt: The ancient Egyptians believed that the painful phenomena came from influences exerted by their gods or spirits of the dead, who used to come into the darkness and penetrate the body through the nostrils and ears.
Ancient India: As they recount the Vedas the concepts of pain is attributed to God Indra and Buddha attributed the pain to the frustration of desires. Although recognizing that pain is a feeling the Buddhists and Hindus gave greater importance to the emotional level of the experience.
Ancient China: According to the Chinese concept, in a normal person are balanced the two unifying but antagonistic forces that are Yin (passive, negative and female force) and Yang (male, positive and active force) and that all parts of the body circulate vital energy called Chi. The deficiency or excess of chi circulation unbalance the two forces, resulting in disease and pain.
Ancient Greece: The ancient Greeks gave much importance to the organs of the senses, they argued that all feelings are accompanied by pain and the more different or contrary between if the subject and the object, more intense will be the sensation of pain perceived by the brain or the heart.
Ancient Rome: Celso felt pain in relation to the phenomenon of inflammation along with flushing, swelling and heat. Galen conducted studies on the physiology of the senses and it re-established the importance of the central and peripheral nervous system; I have a theory of sensations based on nerves, dividing them into three classes that were in charge of different directions and whose center of sensitivity was the brain.
Middle ages and Renaissance: in the middle ages domino the philosophy of Aristotle of the heart as a centre of sensitivity until Alberto Magno proposed the theory that the perception Center was located in the brain. The Renaissance allowed extraordinary advances in chemistry, physics, Physiology and Anatomy, in particular that of the nervous system. During these two periods, there was no progress in the treatment of pain.
17TH and 18th centuries: in the 17TH century were more evidence of the involvement of brainstem in the sensations while many authorities in the matter were still accepting the Aristotelian concept although Descartes widely described his anatomical studies of sensory physiology and I put the theory of specificity. In the 18th century prevailed conceptions of the nature of the pain and the methods abort it and alleviate it and appeared definitions and anatomical descriptions of the sympathetic nervous system. Appears the use of nitrous oxide as an analgesic.
19Th century: At the beginning of the century, as science experimental Physiology arose which allowed the scientific study of General sensations and pain in particular. Towards 1840 starts low pain scientist study the doctrine of energy specifies neural whose theory was that the brain was receiving information about external objects and builds body only through sensory nerve corresponding to the five senses that they were transporting in a particular way the energy that is specific to each sensation. Also important advances occurred in the treatment of pain, morphine was isolated and techniques have been developed to obtain pure crystalline drugs from raw products. In the century XIX thanks to anatomical, physiological and histological studies were raised 2 physiological theories of pain: the specificity and compensated. Specificity (sensory) theory raised that pain is a sensation specifies its own "sensory apparatus" independent of the senses and the intensivity (sum) theory was based on the Aristotelian concept that pain is the result of excessive stimulation of the sense of touch, was based on that each sensory stimulus could cause pain if it reached sufficient intensity. This theory was reinforced to 1894 when it was raised that the specific profiles of nerve impulses that trigger pain are produced by the sum of sensory impulses from the skin coming to neurons in the dorsal horn. (12)
Continued research on pain in the first 60 years of the 20th century and published and obtained data were used in part to support the theory of the specificity, the context or a modification of them. However, in the middle of century specificity theory prevailed. Began to believe in the existence of a center of pain as a result of multiple research and animal experiments with which is came to the conclusion that the lesions at the cortical level rarely nullify pain and often worsened it, which was to think that the crust was inhibitory control of the Thalamic pain Centeri.e., that the center of the pain was in the thalamus.
Theory of profiles: pointed out that all terminations of fiber, apart from those innervating the hair cells are similar, in such a way that the profile of pain is intense stimulation of receptors unspecific product.
Theory of the central sum: in support of the context theory proposed that intensive stimulation which is the result of damage to nerves and tissues active fibers ending in sets of neurons in the spinal cord, which creates abnormal activity in neuronal circuits closed autoexcitatorios.
Fourth theory about pain: are generated as a result of the dispute between the three theoretical groups persistent and proposed that the pain could be separated into two components: the perception that it has and the reaction to it.
The perception of pain, similar to the perception of other sensations is a structural, functional and perceptual properties neurophysiological phenomenon and which is carried out through mechanisms of nerve conduction and reception "relatively simple and primitive". On the other hand, the reaction to the pain is a process complex Psychophysiological covering intellectual functions of the person and that is influenced by experience, culture and various psychological factors that cause huge variations in reaction to the pain threshold. (14)
Sensory interaction theory: it proposes that the somatic afferent fibers of fine diameter and slow conduction and the thin visceral afferents reach sata dorsal spinal cord neurons, and the sum of impulses coming from the thin fibers generates profiles or nervous patterns that are transmitted to the brain to produce pain. Fast action and large diameter fibers inhibit the transmission of impulses from the fine fibers and prevent the sum from occurring.
Gate control theory: the theory is based on the following approaches: to) the transmission of nerve impulses of afferent fibers to spinal cord neurons T is modulated by spinal mechanisms of control for gate in the dorsal horn. (b) the spinal gate control mechanisms are influenced by the relative degree of activity in fibres of large diameter and small diameter; (the activity of large fibers tends to inhibit transmission (closed door) while the activity of fine fibers tends to facilitate the transmission (opens door) c) the spinal gate control mechanism is influenced by nerve impulses that descend from the brain. (d) a specialized system of rapid conductive fibers of large diameter called central control trigger trigger selective intellectual phenomena which from that moment will influence through descending fibers in spinal control mechanisms modulating properties by gate. (e) when the stimuli coming from neurons in the spinal cord transmission exceed a critical level, they activate the action system, nerve regions that underlie the complex sequential pattern of behavior and characteristic of the pain experience. (17)
Psychological theories and behavioral: raises the subjects to feel and describe their pain with the same terms that make it subjects with demonstrable organic alterations and that their sicogeno pain is as real to them as that caused by alterations somatogenas.