Measurement of pain in the prehospital setting using a visual analogue scale

Abstract

Introduction: The aim of this study was to use a visual analogue scale (VAS) to measure the adequacy of prehospital pain management. Patients reported pain severity at two points in time during treatment and transport by ambulance paramedics. The change in pain score was compared with a benchmark reduction of 20 mm that has been shown to correspond with the minimum clinically significant change in pain perception reported by patients.

Methods: This prospective, observational study used a VAS to record pain severity among patients reporting pain who were transported to a hospital by paramedics. Patients used a VAS to score pain severity during the initial patient assessment process (T0), and again at the hospital of destination (Tend). This study reports the mean changes in the scores, and the percentage of cases for whom the difference between T0 and Tend in the study population achieved or exceeded the 20 mm benchmark. A survey also was administered to paramedics who participated in this study in order to identify attitudes, values, and beliefs relating to the measurement of pain.

Results: A total of 262 patients were enrolled in this study. The mean value for the reduction in VAS (T0-Tend) was 18.2+/-23.9 mm [+/-SD] (Median = 14.0mm, 95% confidence interval (CI) = 15.3-21.1 mm). One hundred and thirty-four patients (51.1%) did not receive analgesia (either morphine sulfate or methoxyflurane). The mean initial (T0) pain score for the no-analgesia group was 54.5+/-24.7 mm [+/-SD], with the mean value for the change in VAS (T0-Tend) = 10.6 mm (median = 5 mm, 95% CI = 6.4-14.8 mm). Forty-six patients (17.6%) recorded some deterioration in their pain score at Tend (T0-Tend<0 mm). Survey results identified attitudes that may affect paramedics' pain management practice.

Conclusion: The results suggest that inadequate analgesia is an issue in this study setting. Effective analgesia requires formal protocols or guidelines supported by effective analgesic therapies along with education that addresses attitudes that may inhibit pain assessment or management by paramedics. Regular audits form part of clinical quality assurance programs that assess analgesic practice. However, such audits must have access to data obtained from patient self-reporting of pain using a valid and reliable pain measurement tool.