Pain Scales

There are several species-specific pain scales to assess both acute and chronic pain in animals (Table 20.7). The use of pain scales decreases subjectivity and observer bias, therefore resulting in more effective pain management leading to overall better patient care.

Acute post-operative pain scales for dogs include the Colorado State University Canine Acute Pain Scale, and the University of Glasgow Short Form Composite Pain Score. The Colorado State University Canine Acute Pain Scale contains psychological and behavioral indicators of pain, as well as a pain response to palpation [1]. The University of Glasgow Short Form Composite Pain Score is a validated pain scale that is considered a clinical decision-making tool for dogs in acute pain, an indicator of analgesic requirement, and it includes 30 descriptors and 6 behavioral indicators of pain [2].

The UNESP-Botucatu Multidimensional Composite Pain Scale is validated in cats for acute, post-operative pain. This pain scale assesses pain expression through behavior, vocalization, and reaction to palpation of a surgical wound. In addition, psychomotor change of posture, comfort, activity, and attitude are included as well as physiological variables such as appetite and arterial blood pressure. Colorado State University developed a Feline Acute Pain Scale for acute, post-operative pain. This scale is based on psychological and behavioral responses, response to palpation of surgical wound, and body tension. The University of Glasgow has developed a facial expression tool to assess acute pain in cats. This facial expression scale was designed using the ear position (slope of line joining base of ear and tip of ear) and the muzzle/cheek shape. Caricatures were developed and sequenced as a facial scoring scale; one depicting the ear position and the other depicting the nose/muzzle shape. Standardized mouth and ear distances when combined showed excellent discrimination, correctly differentiating pain-free and painful cats in 98% of cases [3].

There are three validated canine chronic pain scales that were created for owners to assess their dog’s pain level at home; they include the Helsinki Chronic Pain Index (HCPI), the Canine Brief Pain Inventory (CBPI), and the Liverpool Osteoarthritis in Dogs (LOAD). The HCPI was validated in 2009 [4] for canine osteoarthritis, and it evaluates demeanor, behavior, pain, and locomotion. The CBPI was validated for canine osteoarthritis in 2007 [5] and osteosarcoma in 2009 [6]. It involves assessing pain severity, pain interference with function, and quality of life. The LOAD was validated to evaluate canine elbow osteoarthritis in 2009 [7], and it assesses a dog’s mobility in general terms and with exercise.