Effect of audible static on blood pressure measurement by Doppler ultrasonic sphygmomanometry in cats

Objectives The aim of the present study was to determine whether the use of headphones to eliminate audible static during Doppler ultrasonic sphygmomanometry affects blood pressure (BP) measurement in conscious young adult (aged 1-6 years) and mature adult/senior (aged >= 7 years) cats.Methods A randomized crossover study was conducted. Healthy client-owned cats (>1 year) were enrolled. Blood pressure measurements were obtained twice, 14 days apart, with or without the use of headphones worn by a veterinarian. A fear, anxiety and stress (FAS) score (0 = relaxed; 4 = severe signs) was recorded. A linear mixed-effects model was used to compare the effect of wearing headphones on BP measurement.Results In total, 18 young adult and 14 mature adult and senior cats with a median age of 5 years (range 1-14 years) were enrolled. Of the cats, 47% (15/32) had an average BP measurement that was at least 10 mmHg higher when using headphones compared with when not using headphones, of which a majority (11/15, 73%) were young adult cats. The average BP measurement was not different when using headphones compared with when not using headphones (mean difference -7 mmHg; 95% confidence interval -14 to 0.6; P = 0.07). When compared within age groups, the average BP measurement taken when using headphones (125 +/- 15 mmHg) was lower compared with the measurement taken when not using headphones (137 +/- 17 mmHg) in young adult cats (P = 0.02).Conclusions and relevance The reduction in the average BP measurement with the use of headphones suggests this method may be helpful in reducing situational hypertension, particularly in young adult cats. Our findings also highlight the importance of consistent use of headphones when comparing serial measurements in a cat.