Relationship between physiological factors and clinical pain in dogs scored using a numerical rating scale

Abstract

."g scale A study was designed to investigate the association between heart rate, respiratory rate and pupil dilation and a subjective pain score allocated using a numerical rating scale (NRS). Four groups of dogs (n = 17 to 20 per group) were included: orthopaedic surgery cases, soft tissue surgery cases, dogs with medical conditions and healthy dogs. Each dog was examined by five veterinary surgeons within a four-hour period. When examining each dog, the observers recorded heart rate, respiratory rate, pupil dilation (present or absent) and a pain score using a NRS (range 0 to 10). For surgical cases, all study assessments were carried out between 21 and 27 hours following the end of surgery. The correlation coefficients between physiological parameters and NRS score were small but, depending on the analysis, were significant for heart rate and NRS score (P < 0.05). However, the size of the coefficient, 0.168, indicated that the relationship was not biologically significant. There was no association between respiratory rate and NRS score. Analysis of the relationship between NRS score and pupil dilation indicated that there was an association between this factor and pain, depending on the analysis. This was significant for the surgical groups (P < 0.05) but not for the other groups.These findings indicate that heart rate and respiratory rate are not useful indicators of pain in hospitalised dogs. It is also unlikely that pupil dilation will be a useful tool in the assessment of pain.

Analgesic effects of butorphanol tartrate and phenylbutazone administered alone and in combination in young horses undergoing routine castration

“…In our study, there were no significant differences in heart rate, respiratory rate, or rectal temperature among the 3 treatment groups. Our findings are consistent with those of other studies 22,35,41,42 of physiologic indicators of postoperative pain in horses. Heart rate is affected by factors other than pain, including movement, eating, hydration status, and variations in sympathetic and parasympathetic tone.…”

Tolfenamic acid and meloxicam both provide an adequate degree of postoperative analgesia in dogs undergoing ovariohysterectomy

“…However, some researchers consider physiological signs to be non-specific indicators of pain (Kukanich et al 2011). Previous reports also showed no correlation between physiological indices and pain severity (Hansen et al 1997;Holton et al 1998). In the current study, there were no significant differences in the other physiological variables measured among the three groups, except for the HRs at 4 and 6 h in group C compared with group T and group M, respectively (Table 2).…”

The Challenges of Assessing Osteoarthritis and Postoperative Pain in Dogs

“…The physiological data descriptors include defined ranges for increases in heart rate and respiratory rate with higher scores being assigned to larger increases in postoperative heart and respiratory rates compared to presurgical values. However, this assigned scoring assumes that the increases in these physiologic parameters are specific and direct indicators of pain intensity, which is a correlation that has not been established in dogs (70,71).…”

“…Objective physiologic measurements such as increases in heart rate and respiratory rate, increased mean arterial blood pressure and pupil dilation, and increased plasma cortisol concentrations have not been demonstrated as sensitive demarcations between nonpainful and painful animals (dogs and cats) as a means to assess severity of pain (70)(71)(72). These changes in physiologic measurements are not specific pain indicators and may also be associated with physical exertion, fever, and anxiety (73).…”