ABSTRACT. The purposes of the present study were to determine the systolic blood pressure (SBP) of clinically normal and conscious cats, and to set up reference values of feline SBP for subsequent clinical application. SBPs were measured in 53 healthy cats using an ultrasonic Doppler device. The mean SBP was 133.6 ± 16.0 mmHg (range, 110.0-180.0 mmHg). The distribution of SBP values was not significantly affected by factors such as breed, body condition score, or age (P>0.05), but SBP values of female cats were significantly lower and more variable than those of males (t test, P=0.004; F test, P<0.001). Feline SBP between 114.3 mmHg and 149.5 mmHg was considered indicative of normotension. SBP values higher than 159.3 mmHg were defined as hypertension, and those less than 104.5 mmHg were determined as hypotension. KEY WORDS: clinically normal, Doppler, feline reference value, systolic blood pressure.J. Vet. Med. Sci. 68(8): 827-832, 2006 Blood pressure (BP) is an important dynamic measurement of cardiovascular system function and is affected by physical and pathological conditions [5,7,9,12,13,27]. In feline medicine, various medical disorders, such as chronic renal failure, hyperthyroidism, retinopathy, and left ventricular hypertrophy, are associated with abnormal BP [4,7,16,17,20,[22][23]. Although BP measurements are not routinely performed in general feline practice, numerous clinical studies and case reports provide technical and diagnostic information [4,11,16,19,23,25]. Indirect BP measurements can be obtained by either Doppler or oscillometric methods, since both are noninvasive and suitable for clinical use. In conscious patients, the indirect Doppler technique has a better successful measurement rate, shows less sensitivity to respiration or movement of the animals, and has a shorter operating duration than oscillometric methods [14,21,28]. To date, only a few studies have surveyed feline BP distribution or generated reference ranges with the Doppler method, and there are some conflicting opinions on criteria for feline hypertension [15,16,20,25].The aims of the present study were to assess the distribution of systolic blood pressure (SBP) in clinically normal and conscious cats with an indirect Doppler method, and to establish reference values for feline SBP in clinical settings. MATERIALS AND METHODSFifty-three clinically normal cats at the National Taiwan University Veterinary Hospital were enrolled for this survey. All cats were assessed by physical examinations, clinical signs, chest radiographs, and routine blood profiles to exclude renal disease, cardiorespiratory diseases, heartworm infestation (Feline Heartworm Antigen Test Kit, IDEXX Laboratories, Maine, U.S.A.), or other conditions that might affect blood pressure directly. Breeds included 30 domestic shorthairs; 11 Persians; Himalayan and Persian-crossed (3 each); Siamese and domestic longhairs (2 each); and 1 American shorthair and 1 Siamese-crossed. Of these 53 cats, 32 were female and 21 were male. The mean age was 3.7 ± 2.8 years, a...