Influence of music and its genres on respiratory rate and pupil diameter variations in cats under general anaesthesia: contribution to promoting patient safety
It is widely accepted that, in humans, music confers numerous benefits. An extensive body of research indicates that these benefits extend even to patients under general anaesthesia, and include reduced perceived pain, anxiety and stress. According to this study music is likewise beneficial for cats in the surgical environment. But not all music is equal in this respect – cats, it seems, benefit most from classical music.
The clinicians studied 12 female pet cats undergoing surgery for neutering, and recorded their respiratory rate and pupil diameter at various points to gauge their depth of anaesthesia. The cats, which had been fitted with headphones, were meanwhile exposed to 2 minutes of silence (as a control), followed randomly by 2 minutes each of Barber’s ‘Adagio for Strings (Opus 11)’, Natalie Imbruglia’s ‘Thorn’ and AC/DC’s ‘Thunderstruck’. The results showed that the cats were in a more relaxed state (as determined by their lower values for respiratory rate and pupil diameter) under the influence of classical music, with the pop music producing intermediate values. By contrast, the heavy metal music produced the highest values, indicating ‘a more stressful situation’. Dr Carreira and his colleagues plan to continue their studies by looking at the influence of music on other physiological parameters
Objectives The aims of the study were to recognise if there is any auditory sensory stimuli processing in cats under general anaesthesia, and to evaluate changes in respiratory rate (RR) and pupillary diameter (PD) in anaesthetised patients exposed to different music genres, while relating this to the depth of anaesthesia.
Methods A sample of 12 cats submitted for elective ovariohysterectomy were exposed to 2 min excerpts of three different music genres (classical [CM], pop [PM] and heavy metal [HM]) at three points during surgery (T1 = coeliotomy; T2 = ligature placement and transection of the ovarian pedicle; T3 = ligature placement and transaction of the uterine body). A multiparametric medical monitor was used to measure the RR, and a digital calliper was used for PD measurement. Music was delivered through headphones, which fully covered the patient’s ears. P values <0.05 were considered to be statistically significant.
Results Statistically significant differences between stimuli conditions for all surgical points were obtained for RR (T1, P = 0.03; T2, P = 0.00; and T3, P = 0.00) and for PD (T1, P = 0.03; T2, P = 0.04; and T3, P = 0.00). Most individuals exhibited lower values for RR and PD when exposed to CM, intermediate values to PM and higher values to HM.
Conclusions and relevance The results suggest that cats under general anaesthesia are likely to perform auditory sensory stimuli processing. The exposure to music induces RR and PD variations modulated by the genre of music and is associated with autonomic nervous system activity. The use of music in the surgical theatre may contribute to allowing a reduced anaesthetic dose, minimising undesirable side effects and thus promoting patient safety.
Filipa Mira, Alexandra Costa, Eva Mendes, Pedro Azevedo, and L Miguel Carreira
Influence of music and its genres on respiratory rate and pupil diameter variations in cats under general anaesthesia: contribution to promoting patient safety Journal of Feline Medicine and Surgery 1098612X15575778, first published on March 30, 2015 doi:10.1177/1098612X15575778