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Drugs or drums: what relieves postoperative pain?
1Department of Anaesthesia, University of Western Ontario Medical School, London, Ont. N6A 5C1 Canada.
Pain
|April 1, 1979
Summary
Demand analgesia (DA) precisely measures patient pain relief responses to hydromorphone. While most patients adapt to dose changes, some respond to non-drug factors, indicating context influences placebo effects.
Area of Science:
- Pain Management
- Pharmacology
- Cybernetics
Background:
- The cybernetic model of analgesia describes a servo-loop of pain perception and medication.
- Clinical pain management is often obscured by "noise" from multiple caregivers and delayed medication.
- Demand analgesia (DA) offers patient-controlled, prompt pain relief and aids acute pain research.
Purpose of the Study:
- To investigate patient precision in responding to hydromorphone dose variations.
- To quantify the contribution of drug and non-drug factors to pain relief.
- To explore the influence of circumstances on placebo responses.
Main Methods:
- A double-blind study involving 34 post-surgery patients using DA with hydromorphone.
- Varied hydromorphone delivery amounts in response to patient-triggered doses.
- Monitored patient adaptation of dosing intervals and identified non-drug responders.
Main Results:
- Most patients (27/34) successfully adapted to up to 4-fold changes in hydromorphone delivery.
- A minority (7/34) responded to non-drug cues, identified as "placebo reactors."
- Drug action contributed 78% to pain relief in drug responders vs. 40% in non-drug responders.
Conclusions:
- Patient-controlled analgesia (PCA) systems can precisely assess drug efficacy and non-drug influences.
- Significant contributions of both drug and non-drug factors were observed in all patient groups.
- The tendency to act as a placebo reactor may be situational rather than an innate trait.