Pain & its management R.Fielding Dept. of Community Medicine

Outline Learning objectives Perception - a summary Pain and the perceptual model Pain components Pain theories Pain management Summary & conclusions

Learning Objectives evaluate why pain is best understood when considered as a perceptual process summarize and exemplify the four components of the pain experience recognize that pain is not equivalent to sensation define pain discordance, or desynchrony evaluate the role of social factors in pain experience

Perception - a summary Ascription of meaning to sensory & subjective experience. It involves (re)organization of the perceptual field. There are important differences between sensation (sensory nerve activity, light, sound, etc.) and meaning. We respond not to sensory activity per se but to the signs, things, ideas, etc. that different patterns of sensory activity represent.

Features of perceptual processes –stability –selective attention –figure-ground –hypothesis-testing –contexts –intensity Contexts, expectations and past experience.

Pain and the perceptual model Characteristics of perceptual phenomena: Have features shown on previous slide; People experience identical sensory input differently from one another; A person’s experience of an identical sensory input differ when non-stimulus features are changed.

Does pain fit the perceptual model? 1. Sensory features : Pain is an abstract concept referring to: A personal private sensation; A harmful stimulus signalling harm; A pattern of responses to protect from harm (Sternberg, 1968).

2. Affective/motivational factors Pain experience varies according to: affective (mood) state anxiety level Pain stimulates avoidance

3. Cognitive components. Psychological status determines analgesia effectiveness Beecher (1952). Placebo effects: <30% drop in pain reports after sham “morphine” saline injection. Wartime injuries are often associated with “less” pain than comparable injuries acquired in peacetime.

4. Behavioural components. Pain motivates help seeking behaviour : Pain behaviour has communication aspects (social roles) e.g. crying/ moaning/ complaints seen in health care utilization. Chronic pain patients show marked changes in physical behaviour as a result of their cognitive behaviour.

4. (cont.) Cultural variation in pain expression (Zbrowski, 1968). 5. Concordance / desynchrony Pain features are incongruent with each other. Usually, organic state is static but the emotional state is labile. Religious states where injury inflicted but little pain experienced.

6. Chronic pain: Different from acute pain; Duration prolonged, may be unremitting; Intensity may vary; Meaning is ambiguous.

In summary, pain shows many characteristics of perceptual phenomenon, being influenced by expectation, contexts, cognitions and affect, and has clear culturally determined behavioural components.

Pain theories 1. “doorbell” theories: 300 years old, naive. No consideration of perceptual. 2. comparative A / C fibre activity 3. Summation (firing frequency) theories 4. gate theories

Pain management Acute pain indicates danger, enables matching of experience with expectation for danger control (Johnson & Leventhal, 1975).

Predictability & perceived control important (less analgesia used when self-administered than when administered by others, e.g. nurse). Distraction, especially for kids. (Beales, 1979) Relaxation.

Benign chronic pain: careful management more critical Avoid PRN, Effective social & emotional management, CBT, increase sense of control Emotional control

Expand perceptual field, Sensory recalibration, Lower muscular tension, Reduce anxiety re pain, Biofeedback, Counter stimulation

Malignant pain Cancer pain is physiological and also psychological suffering. Most cancer patients experience some pain. 1 patient in 5 has moderate to severe pain at sometime during past month.

Analgesia is generally inadequate. Rarely are aspects of pain other than sensation addressed.

Social influences Nurses expectations of pain means: They often make no formal assessment of acute post op. pain; They significantly under estimate patients’ reported levels of pain, rating female patients as having less pain than males.

There are significant delays between requests for analgesia and administration, even when analgesia is prescribed. Nurses rely on pharmacology rather than other methods for pain control.

Summary & conclusions Among the most common presenting symptoms Pain is primarily a perceptual eventbut is usually considered and treated as a physiological event

Research clearly indicates pain is subject to social and organizational influences and that health workers do not respond as if pain were as much of a problem as it is. Patients with cancer are often chronically under medicated despite high reported levels of pain.