Chapter 42 Nonpharmacologic Control of Pain
Introduction
When treating a patient for pain, the clinician must first determine the primary cause, the pathogenesis, and the secondary or contributing factors. The relief of pain may then be achieved by removal of the primary cause (e.g., cure of an infection), neutralization of the effect of the stimulus (e.g., emollients for an ulcer), relief of discomfort (e.g., biofeedback), suppression of the disease process (e.g., anti-inflammatory agents), and dulling or obliteration of the sense of pain (e.g., analgesics or acupuncture).1
The Experience of Pain
A Psychological Model
In the psychological model, the brain infers information from bodily signs and integrates it with existing personal and situational variables to direct behavior. When consideration must also be given to the interactions with interested observers, such as physicians, family members, and birth attendants, who influence the interpretation with their own experiences and attitudes about pain, the complexity becomes even greater.
According to this model, which does not differ in essence from a general model of stress, a primary appraisal of the personal danger or threat posed by the painful stressor is followed by a secondary appraisal of one’s ability to cope, based on emotional feedback and contributions of situational and sociocultural response factors. On this basis, a woman in labor could choose to regard pain as “positive,” “functional,” or “creative”; “pain with a purpose”; or, alternatively, “part of a process involving injury.”2 In the course of a pain management program carried out in 84 patients with low back pain, those who more strongly endorsed “organic” concepts about the nature and treatment of pain reported higher levels of disability, whereas reductions in reported “organic” pain beliefs improved reported disability, and endorsement of “psychological” concepts about the nature and treatment of pain was not associated with disability.3 Several studies indicated that “catastrophizing” predicted pain or was associated with lower pain tolerance.4,5 This conceptualization of painful stress suggests that intervention could be successful at several levels: cognitive patterning, physiologic arousal associated with emotional stress, and control of environmental stimuli. Examples of appropriate strategies are cognitive coping skills such as restructuring and utilization of preparatory information and attention shifts; muscular relaxation, physical or electrical stimulation, and biofeedback techniques; and structuring of the environment in a way conducive to effective coping (such as by making it nonthreatening and comfortable).6
Neuropsychological Mechanisms of Pain
According to research on the mechanisms of pain, pain can be treated not only by anesthetic blocks, surgical intervention, and the like, but also by influencing the motivational, affective, and cognitive factors.7 The traditional specificity theory of pain, first enunciated by Descartes in the seventeenth century, holds that pain messages are conducted from specific pain receptors at the periphery through discrete pathways to pain centers in the brain. However, there are individual differences in pain responses; pain is not consistently stopped by cutting or blocking of the “pain pathway,” and it is now known that nonpainful types of stimulation activate the A-δ and C fibers (see next paragraph) that are associated with pain. Therefore, later modifications of pain theory took into account patterning of nerve impulses over time to reflect differences in degree and intensity of stimuli and summation of signals from an extended area.8
The currently accepted view of pain is the gate control theory, which Melzack and Wall9 formulated in 1965. Based on neurologic data and a categorization of the words used to describe pain, this theory conceptualizes the pain experience as having sensory discriminative, motivational affective, and cognitive evaluative components or modalities, corresponding to different patterns of nervous impulses. Neurologically, a specialized cluster of nerve cells in the substantia gelatinosa of the spinal column is thought to operate like a valve or gate, controlling nerve signals before they evoke the perception of, and response to, pain. Besides this monitoring of sensory data in the central nervous system, gating is also influenced by the relative amount of activity in large (A-β) and small diameter (A-δ and C) nerve fibers. The large fibers tend to inhibit transmission, or close the gate, preventing pain, and the small fibers tend to facilitate transmission, or open the gate, resulting in pain. The fact that large fibers are activated by pressure, touch, massage, and vibration suggests a mechanism for such pain control techniques as acupressure, acupuncture, and transcutaneous electrical nerve stimulation (TENS). Such stimulation apparently closes the spinal gate via the large fiber system. Melzack and Casey7 expanded this theory by proposing the possibility of a higher level gate, in the reticular or limbic structures of the brain, that probably mediates the drive to escape from unpleasant stimuli. At central nervous system levels, the biochemical mechanisms of gate control may involve the endorphins, natural morphine-like substances that have been implicated in the pain controlling effects produced by acupuncture.10
Pain in Childbirth
A psychological and/or social learning approach to pain emphasizes control of motivation, expectation, focus of attention, stress, and feelings of anxiety, depression, and helplessness. Factors specifically operative in labor pain involve these as well as social support and the physiologic factors of hunger, rest, and muscular tension.11All of these factors can contribute to the interpretation of pain being placed on the nociceptive message provided by uterine contractions. The influence of motivation on labor pain was effectively demonstrated in a prospective study of maternal attitudes toward pregnancy in 8000 American women. One of the factors found to be strongly related to maternal attitude toward having a baby was the need for analgesics in labor.12
Cultural conditioning may also be fundamental to the labeling of childbirth as painful. Throughout most of the world, analgesics are not required for labor; a Japanese anesthesiologist suggested that the idea of “painless delivery” is a strange one to his culture.13 American women, in contrast, “live through a largely self-fulfilling prophecy of birth as a painful, terrifying ordeal, and/or as a medical, drugged process over which they have no control.”11 This idea relates to body fantasies of injury, brought about in a hospital environment where distress is an expected response to the expulsive reflex.2
Pain Control
Moderating Variables and Psychological Techniques
Psychological Strategies
For example, on the repression–sensitization axis, repressors may be characterized as people who avoid having to cope with pain. Sensitizers, however, have an obsessive need to cope; they like to be informed in advance about the situation and to have control over it. The superior initial tolerance exhibited by repressors in response to heat and pressure stimuli disappeared in repeated trials, showing that the sensitizers’ predilection for challenge enabled them to endure long-term pain better.
The importance of individual difference variables is also illustrated by the observation that one third of patients undergoing surgical operations do not request pain-killing medication.23 This common ability to suppress pain indicates that not all surgical patients consider themselves passive victims. During the postoperative period, pain persists longer for those who accept medication.
Cognitive Strategies
The impetus for devising cognitive strategies to promote tolerance of pain has been particularly supported by investigations showing that pain tolerance increases with greater predictability and perception of control.24–28 Similarly, preparatory communications and information received before the onset of experimental or surgical pain consistently decreases the subjects’ perception of pain.29–31 Animal studies have demonstrated higher rates of instrumental responses when painful shocks are signaled than when they are unsignaled.32 Kanfer and Seidner33 found that subjects who could advance slides of travel pictures at their own rate tolerated ice water immersion of the hand longer than yoked subjects whose slides were changed by the experimenter.
When surgical patients were given a sense of control by being provided with preparatory information about postoperative discomforts and operative care, in combination with training in rehearsal of realistic, positive aspects of the surgical experience, they showed a significant reduction in postoperative anxiety (as indicated by nurses’ observations), requests for sedatives, and length of hospital stay.34
A typical cognitive behavioral procedure utilizes “stress inoculation,” beginning with an educational phase (in which the client is given a conceptual framework for understanding the nature of his or her stressful reactions), followed by rehearsal of behavioral and cognitive coping skills, based on a set of coping self-statements generated by the client in collaboration with the therapist. Such cognitive-behavioral techniques, sometimes in combination with electromyographic biofeedback control, have been found successful in treatment of chronic low back pain.35–37 Also, cognitive-behavioral strategies have been effective in alleviating the pain of irritable bowel syndrome,38 temporomandibular joint syndrome,39,40 cancer,41 migraine headaches,42 rheumatic conditions,43–45 fibromyalgia,46 and complex regional pain syndrome.47 This emphasis on conceptualization, preparatory information, and cognitive transformation seems to have been incorporated into the Read method of natural childbirth, which replaces fear with knowledge about birth.12 Sheila Kitzinger,2 in her method of prepared childbirth, similarly emphasizes the necessity of “acquiring knowledge and understanding of what labor involves, the terminology used by obstetricians and midwives, and information about what happens in hospitals.”
A study by Stevens and Heide48 conducted at the University of Wisconsin used iced water to test perception and endurance of pain in subjects who had been taught methods used in childbirth education classes. Control subjects for this training and an additional control group were offered only distraction during the tests. Those who had been taught the techniques reported only about half the pain of that reported by control subjects and endured it 2.5 times longer. The prepared childbirth strategies improved with practice, were effective for pain lasting longer than most contractions in labor, and were more effective than distraction techniques.48
Attention-Focusing
Distraction or focused attention, mostly utilizing the rhythms of the breath, is essential to the Lamaze method, the most popular prepared childbirth program in America, and is important in the Bradley and other methods. Sheila Kitzinger2 described the controlled attention focusing as:
Stevens and Heide48 found that attention-focusing functions effectively as an analgesia for labor pain. Such strategies are strongly supported by much psychological research. Hospitalized children with chronic illnesses who were taught distraction techniques were able to reduce measures of distress before and during medical procedures such as intramuscular and intravenous injections.49 In a study of patients with burn pain, sensory-focusing techniques were more successful than distraction techniques in controlling pain, and both were more successful than standard care.50 The focus may be on a competing response, as in a study by Kanfer and Goldfoot,51 which showed that when attention was directed to self-presented external slides, individuals were able to increase their tolerance of the pain of cold water. Focus on a competing response was also shown in the use of hypnosis as an analgesic and in the meditative states of Raj yogis, who pinpointed attention on the tip of the nose or a point on the back of the skull, and then did not react physiologically to cold water, bright lights, or sudden sounds.52,53 Other adepts in unusual feats of pain tolerance, such as having spikes stuck through the skin, either maintained an unfocused attitude, without evaluation, or pinpointed attention totally on the pain, but without evaluation.54 In such cases, the attitude of detachment from the pain can be reflected by an undisturbed electroencephalography (EEG) pattern of α- or β-waves throughout performance of the feat.
