Patient Consultation about a Trial of Therapeutic Plasma Exchange for Complex Regional Pain Syndrome.

BACKGROUND:Complex regional pain syndrome (CRPS) is a severe post-traumatic chronic pain condition affecting distal limbs, for which few effective treatments exist. Complex regional pain syndrome is listed in the 2016 American Society for Apheresis guidelines as an indication for plasma exchange treatment, but patient perspectives are lacking.STUDY DESIGN AND METHODS:We convened a "patient and public consultation exercise." Supervised by a clinical ethicist, the case for using therapeutic plasma exchange (TPE) was presented by a researcher and two TPE experts to five patients with severe, long-standing CRPS and to one relative. Discussions were recorded and transcribed.RESULTS:Participants supported the technology's use but expressed concern that the small trauma of repeat cannulations of CRPS unaffected limbs might theoretically cause a spread of the condition, a risk which requires highlighting when taking consent. For a preliminary trial, the participants proposed to include no less than 10, preferably 20 participants. They suggested that the threshold for a decision to conduct a definite trial based on preliminary trial results should be set no higher than 1/5 patients achieving >30% pain reduction in the preliminary trial, with half of these responders achieving >50%. The use of sham-TPE and a long trial duration (1 year) of a definite, parallel trial was considered acceptable, provided patients would be offered voluntary swap to the other trial arm at the end of the main trial period.CONCLUSION:These results provide pertinent patient views about TPE treatment which can inform both clinical consultation and consent procedure and the design of future trials.