The use of stop signals to reduce the pain and distress of patients undergoing a stressful medical procedure: An exploratory clinical study

The present study investigates stop signals and their effects on the pain a nd distress of patients undergoing a stressful medical procedure. Thirty-si x chronic pain patients (17 men, 19 women) attending an out-patient operati ng theatre for diagnostic nerve blocks/local anaesthetic injections were al located to one of two conditions (experimental and control). All patients r eceived a standard information leaflet concerning the forthcoming injection s. Additional information was given to those in the experimental group on f our occasions (three orally, one written) before the injections which state d that they could halt the procedure at any time by saying 'stop'. Subjecti ve measures of anxiety, pain, distress, sense of control over the procedure as well as observer ratings of patient distress and pain behaviour were ob tained before, during and after the injections. After initial differences i n pre-injection pain were controlled for the experimental group, patients r ated themselves as less distressed during the injections and recorded lower state anxiety following treatment. In view of various methodological limit ations of the present study its findings may only be accorded 'pilot: study ' status. These limitations are explored in the discussion along with their implications for a more robust replication study. Nevertheless the present findings provide tentative support for the hypothesis that: the use of sto p signals can reduce the stressful nature of diagnostic nerve blocks.