Use of a new finger-mounted device to compare mechanical nociceptive thresholds in cats given pethidine or no medication after castration.

Mechanical nociceptive thresholds are regularly used to determine the efficacy of analgesic agents both experimentally and clinically in a variety of species. The 'pressure of palpation device' (PPD) was developed for use in cats and is a small battery operated device with a finger-mounted force sensing resistor (FSR, Interlink Electronics, Northumberland. UK). The PPD was used in a study assessing the analgesic efficacy of pethidine after castration in cats. Pethidine was demonstrated to prevent the development of post-operative scrotal hypersensitivity for up to 2 hours after castration, whereas cats given no analgesics showed marked hyperalgesia immediately after surgery. Visual Analogue Scale (VAS) pain scores after castration showed a similar analgesic effect of pethidine. These results suggest that the PPD could become a useful research tool to assess the effectiveness of analgesic agents in the cat.