Abstract
Perioperative pain involves both neurogenic and inflammatory mediators. The neurogenic component is produced by the intense stimulation of the surgical procedure itself. However, inflammatory mediators resulting from tissue damage and the release of certain cytokines provoke the inflammatory response. Both the neurogenic and inflammatory elements create central nervous system (CNS) excitability. While conventional pain management responds to pain as it occurs, rather than anticipating it, a more appropriate protocol may involve pre-emptive administration of analgesic medication. By beginning this administration prior to surgery and continuing it throughout the rehabilitation process, CNS pharmacological agents are utilised to achieve the following goals: 1.) decrease the neurogenic component at the wound site; 2.) depress afferent pathways; and 3.) decrease central sensitisation in the spinal column.
Our experience with such pre-emptive analgesic clinical trials have included implementation of three different protocols in three groups of patients, Groups A-C. In Group A, a continuous epidural for 72-hours was utilised. A short-term epidural for 2–3 hours, followed by the use of scheduled opioid drugs and the use of anti-inflammatory medications, was used in Group B. Finally, Group C included spinal analgesia with shortacting morphine and the continued use of patient-controlled analgesia (PCA) pumps. In all groups, patients were monitored for the return of motor function, respiratory depression, ileus, pain relief, efficacy in analgesia maintenance, and cost. The following trends were observed among the variances: 1.) approximately equal length of stay in all three groups; 2.) decreased motor function in the continuous epidural group (Group A); 3.) increased ileus in the spinal group (Group C); 4.) equal pain relief in all three groups; 5.) high maintenance in the continuous epidural group (Group A); and 6.) decreased cost when continuous epidurals (Group B) were utilised.
In conclusion, of the three methodologies implemented, the continuous epidural had a high failure rate (26%). While spinal analgesia is technically easier and less expensive to perform, it has a poorly defined dose response curve and is associated with an increased incidence of ileus. The scheduled opioid medications proved effective. Pre-emptive analgesia not only significantly suppresses pain, it also provides protective sensation. Our recommendation for pre-emptive pain management consists of the use of multi-modal analgesics attacking various sites along the pain pathway, including regional blocks, oral and parental opioids, topical anaesthetics, and ice. However, ongoing study is required to further delineate appropriate protocol, thorough assessment of consequences, and complications associated with all methodologies. Future protocols to be evaluated at this practice include the local injection of bupivacaine hydrochloride prior to wound closure, in addition to assessing the postoperative integration of rofecoxib into the pain management regime.
The abstracts were prepared by Mrs Dorothy L. Granchi, Course Coordinator. Correspondence should be addressed to her at PMB 295, 8000 Plaza Boulevard, Mentor, Ohio 44060, USA.
