Comparison of Doppler ultrasonic sphygmomanometry, oscillometry and high-definition oscillometry for non-invasive blood pressure measurement in conscious cats.

OBJECTIVES: Systemic arterial hypertension is a common occurrence and can have serious adverse consequences in cats. Therefore, measuring blood pressure is very important. There are many indirect blood pressure measurement devices available. This study compared Doppler, oscillometric (petMAP Graphic II, SunTech Vet20, the Cardell Insight-X0000) and high-definition oscillometry devices for the non-invasive measurement of blood pressure in conscious cats. METHODS: In this prospective study, blood pressure was measured in 32 cats using the different devices according to the recommendations of the American College of Veterinary Internal Medicine Consensus Statement. Blood pressures (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), time to complete measurements, number of attempts needed, coefficient of variation (CV) between the blood pressure measurements of the different devices, ease of completing measurements and apparent stress level of the cat were assessed. RESULTS: There was a significant difference between devices in the time taken to obtain blood pressure readings and the number of attempts necessary to obtain six reliable measurements. The CV of the Doppler device was significantly smaller than that of the rest of the devices, but there were no other differences between the devices. The mean SBP, DBP and MAP measured by the petMAP device were significantly higher than the measurements from the other devices. The perceived ease of measurement was not significantly different between the various machines. The perceived level of stress of measurement with the Doppler device was significantly higher compared with the other devices but did not lead to an increased SBP. CONCLUSIONS AND RELEVANCE: Using a Doppler device to measure blood pressure in conscious cats is fast, relatively easy and gives reliable results. A disadvantage is that the Doppler device can only measure SBP, while oscillometric devices also provide DBP and MAP. However, in veterinary medicine, systolic hypertension is considered the most relevant.

Doppler ultrasound is more accurate than pulse oximeter plethysmography in the measurement of systolic arterial pressure from the median caudal artery in anesthetized dogs.

OBJECTIVE: To compare the accuracy of doppler ultrasound (DOP) and pulse oximeter plethysmography (POP) in the measurement of systolic arterial pressure (SAP) to invasive blood pressure (IBP) in anesthetized dogs. ANIMALS: 40 client-owned healthy dogs > 10 kg. METHODS: Dogs were anesthetized for surgical procedures in dorsal recumbency. Invasive blood pressure was measured from a dorsal pedal artery. DOP and POP device probes were placed over the median caudal artery with a flow-occluding cuff for noninvasive blood pressure measurement. Systolic arterial pressure measured by DOP, loss of pulse oximeter plethysmograph (POPL), and return of pulse oximeter plethysmograph (POPR) were compared to SAP measured by IBP. A linear mixed model was used to determine correlation. Bland-Altman analyses were performed to determine bias, SD, and limits of agreement. The accuracy of DOP and POP was compared to IBP across different tensive states. RESULTS: Conditional R2 values for DOP, POPL, and POPR versus IBP were 0.92, 0.85, and 0.87, respectively (all P < .001). The biases for DOP, POPL, and POPR compared to IBP were +7.6 ± 13.1, +3.9 ± 14.4, and +8.6 ± 15.2 mm Hg (bias ± SD), respectively. Limits of agreement (lower, upper) were (-18.1, +33.3), (-24.3, +32.1), and (-21.2, +38.4) mm Hg for DOP, POPL, and POPR, respectively. DOP and POP overestimated SAP during hypotension (SAP < 90 mm Hg), DOP to a lesser magnitude. CLINICAL RELEVANCE: DOP measured from the median caudal artery may be acceptable for SAP measurement in dorsally recumbent, healthy anesthetized dogs > 10 kg. POP was determined an unacceptable method.

Pulse-wave analysis during routine blood pressure measurement shows potential to distinguish between sinus and nonsinus rhythm.

OBJECTIVE: To investigate whether pulse-wave analysis (PWA) performed by trained evaluators facilitates detection of nonsinus rhythm. ANIMALS: Same-day, high-definition oscillometry pulse-wave data and ECG results of 155 animals (144 dogs and 11 cats) were analyzed. METHODS: In this cross-sectional study, we enrolled 18 participants from various backgrounds, all of whom received PWA training. The ability to distinguish between sinus and nonsinus rhythms was assessed using receiver operating characteristic curve analysis. The pulse-wave datasets were divided into 5 ECG categories. Agreement between ECG diagnoses and PWA-based arrhythmia detection was evaluated using Cohen κ values, and the correlation between the academic year of veterinary students and their κ values was assessed. RESULTS: All cardiology researchers demonstrated satisfactory accuracy in distinguishing pathological rhythms using PWA (area under the curve, 0.704 to 0.761), with the highest accuracy in detecting atrial fibrillation (area under the curve, 0.811 to 0.845). Fair agreement with ECG categorization was achieved by all 3 cardiology researchers, 2 of 5 general practitioners, and 3 of 10 veterinary undergraduates. The veterinary undergraduates' years of study were correlated with their diagnostic performance (Spearman ρ = 0.658; P = .019). CLINICAL RELEVANCE: PWA during routine noninvasive blood pressure measurement showed significant potential for the detection of pathological arrhythmias, notably atrial fibrillation. This approach yielded improved effectiveness when it was used by veterinarians with cardiology experience. Thus, introducing hands-on training courses, particularly those focused on cardiology and interactive workshops, may enable frontline veterinarians to promptly identify arrhythmias using PWA, facilitating timely ECG examinations or referrals.

Evaluation of the agreement between lingual and thoracic limb noninvasive blood pressure with invasive blood pressure measurements in anaesthetized horses.

OBJECTIVE: To evaluate the agreement between noninvasive arterial blood pressure (NIBP) measured from the tongue and thoracic limb with invasive blood pressure (IBP), and to compare NIBP measured from the tongue and thoracic limb in anaesthetized horses. STUDY DESIGN: Prospective clinical study. ANIMALS: A group of eight client-owned healthy horses anaesthetized for scheduled procedures, American Society of Anesthesiologists classification I-II, weighing (mean ± standard deviation) 498 ± 91 kg and aged 7.8 ± 6.75 years. METHODS: Animals were premedicated with intravenous (IV) romifidine (0.04-0.08 mg kg-1) and methadone (0.1 mg kg-1). General anaesthesia was induced IV with ketamine (2.5 mg kg-1) and midazolam (0.05 mg kg-1) and maintained with isoflurane. The facial artery was catheterized for IBP measurements. Systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were recorded from the NIBPtongue, NIBPlimb and IBP every 20 minutes during the procedure. Agreement between NIBP and IBP was evaluated based on the American College of Veterinary Internal Medicine criteria and American Association for Medical Instrumentation criteria using the Bland-Altman method. RESULTS: The mean bias and precision between IBP and NIBP measured from the tongue met the standards for all pressure ranges (< 10 mmHg and < 15 mmHg, respectively). NIBP measurements from the tongue and thoracic limb tended to underestimate IBP measurements. During hypotension, MAPtongue and DAPtongue overestimated IBP, but both precision and accuracy met the criteria. The overall accuracy and precision of NIBPlimb was poorer than NIBPtongue. The percentage of NIBPtongue that differed from IBP by < 10 mmHg was higher than that recorded with NIBPlimb for SAP (46% versus 25%), MAP (77% versus 28%) and DAP (79% versus 19%). CONCLUSIONS AND CLINICAL RELEVANCE: The tongue is a clinically suitable alternative for assessing arterial blood pressure compared with the thoracic limb and can reliably detect hypotension in healthy anaesthetized horses.

Understanding the barriers to blood pressure assessment in cats.

OBJECTIVES: A questionnaire was designed to survey veterinarians and veterinary nurses/technicians on blood pressure (BP) assessment in cats, including ocular examination, encompassing current methodology, indications, uptake and barriers. METHODS: An online questionnaire was produced and promoted to more than 2000 veterinary professionals, of whom 545 answered all questions and 85 answered most questions. RESULTS: Of the participants, 572 (90.8%) were based in the UK and almost all (n = 613, 97.3%) had access to a BP monitor. Of those that had a monitor, most (n = 550, 88.4%) participants had access to a Doppler monitor; 367 (59.0%) participants had access to multiparameter monitors; fewer (n = 202, 32.5%) had access to oscillometric BP monitors. Where applicable, Doppler monitors were most commonly chosen for conscious cat measurements (n = 337, 72.2%) due to the greater 'trust' and 'reliability' of these compared with oscillometric machines. Conscious BP measurement typically involved two members of staff (n = 391, 62.9%). Only 156 (29.1%) participants recommended BP assessment at least several times a week in their interactions with cat owners. BP assessment was routinely recommended in cats with ocular target organ damage (n = 365, 87.7%), chronic kidney disease (n = 346, 78.6%), proteinuria (n = 255, 63.0%) and hyperthyroidism (n = 266, 60.9%). Common equipment-related barriers included 'cuff frustration' and difficulties hearing the pulse signal for Doppler users (72.2% and 71.6%, respectively), and oscillometric machines failing to give a reading at least some of the time (52.8%). Situational hypertension concerns affected many (n = 507, 92.0%), as did lack of time to do the procedure (n = 402, 73.0%). Significant owner barriers included difficulties persuading the owner to bring their cat in for BP checks (n = 475, 86.2%) and concerns over costs (n = 445, 80.8%). Most participants had access to a direct ophthalmoscope (n = 527, 96.5%); however, 399 (73.1%) reported that they struggled to interpret ocular findings. CONCLUSIONS AND RELEVANCE: Significant barriers exist to successful BP assessment in cats. Education and support of clinics should focus on improving confidence with equipment and eye examination.

Agreement Between Tongue-Based Oscillometric and Invasive Blood Pressure in Anesthetized Dogs of Various Weights.

This study aimed to evaluate the agreement between oscillometric blood pressure (OBP) measured from the tongue and invasive blood pressure (IBP) measured from the dorsal pedal artery in anesthetized dogs of various body weights. Forty-five client-owned dogs undergoing general anesthesia for surgery or imaging scan were included; weights ranged from 2.5 to 42.6 kg. Agreement between paired IBP and OBP during normotension was verified with reference standards used in small animals and humans. The data were stratified by body weight (≤5 kg versus >5 kg). In the >5 kg group (n = 29), the bias ± standard deviation for mean (2.1 ± 7.9 mm Hg) and diastolic pressure (-2.7 ± 7.9 mm Hg) exhibited reliability that met human standards (<5 ± 8 mm Hg). However, in the ≤5 kg group (n = 16), the bias ± standard deviation met only veterinary standards (≤10 ± 15 mm Hg) for mean (3.1 ± 10.2 mm Hg) and diastolic pressure (-2.5 ± 12.6 mm Hg). Agreement for systolic pressure did not meet either standard for both groups. This study demonstrates that tongue-based OBP is a close estimate of mean/diastolic blood pressure in anesthetized dogs (>5 kg) during normotension by small-animal and human criteria.

EVALUATION OF OSCILLOMETRIC BLOOD PRESSURE MEASUREMENT USING A FINGER CUFF IN ANESTHETIZED CHIMPANZEES (PAN TROGLODYTES).

Cardiovascular disease is common among chimpanzees (Pan troglodytes), and serial blood pressure monitoring in conscious animals may improve disease surveillance and guide hypertension treatment strategies. The objective of this study was to compare the accuracy of a noninvasive, oscillometric blood pressure monitor using a finger blood pressure cuff with invasively measured blood pressure in anesthetized chimpanzees. Twelve chimpanzees were anesthetized with tiletamine-zolazepam intramuscularly, intubated, and maintained on inhaled isoflurane to effect. Blood pressure measurements, which included systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP), were collected simultaneously from an oscillometric blood pressure cuff placed on a forelimb digit (FBP) and a direct arterial catheter (IBP) every 5-10 min while anesthetized. One hundred paired samples were collected, and results were compared using Bland-Altman plots and analysis. FBP showed good agreement with IBP for SAP, MAP, and DAP but consistently overestimated values compared with IBP. FBP may be useful for serial blood pressure monitoring in conscious chimpanzees.

Cuff size, cuff placement, blood pressure state, and monitoring technique can influence indirect arterial blood pressure monitoring in anesthetized bats (Pteropus vampyrus).

OBJECTIVE: Evaluate agreement between 2 non-invasive blood pressure (NIBP) techniques and invasive arterial blood pressure (IBP) in anesthetized bats using various cuff sizes and cuff positioning while also evaluating its performance during hypertension and hypotension. ANIMALS: 8 bats (1.1 ± 0.2 kg). PROCEDURES: Bats were anesthetized with isoflurane in oxygen. NIBP was measured using oscillometric (NIBP-O) and Doppler (NIBP-D) techniques in the pectoral limb (PEC) and pelvic limbs (PEL) using 3 cuff sizes (1, 2, and 3). NIBP measurements were compared with IBP; systolic (SAPinvasive), mean (MAPinvasive), and diastolic arterial blood pressure (DAPinvasive) during normotension, hypertension, and hypotension. Hypotension was induced with isoflurane (3.8 ± 1.2%) and hypertension with norepinephrine (3 ± 0.5 µg/kg/min). Data analysis included Bland-Altman analyses and 3-way ANOVA. Results were reported as mean bias (95% CI). RESULTS: NIBP-O monitor reported 29% errors, and experienced more failures with hypertension, cuff placement on PEC, and using a size 1 cuff. Across states, an agreement between NIBP-D and MAPinvasive with cuff 2 on PEL (-3 mmHg [-8, 1]), and NIBP-D and SAPinvasive with cuff 3 on PEC (2 mmHg [-5, 9 mmHg]) was achieved. NIBP-D over-estimated SAPinvasive and MAPinvasive during hypertension in both limbs with cuffs 1 and 2. Except during hypotension, NIBP-O underestimated MAPinvasive and DAPinvasive using a size 2 cuff on PEL. CLINICAL RELEVANCE: In anesthetized bats, NIBP-O is unreliable for estimating IBP. NIBP-D shows acceptable agreement with MAPinvasive with cuff size 2 on PEL, and with SAPinvasive with cuff size 3 on PEC across a wide range of IBP values.

Systolic blood pressure measurements with Doppler ultrasonic flow detector and high-definition oscillometry are comparable on population level but show large intra-individual differences in apparently healthy elderly dogs.

OBJECTIVE: Agreement of systolic blood pressure measurements (SBP) between noninvasive blood pressure devices in conscious dogs is poorly studied. Situational hypertension is expected in clinics, but studies are lacking. This study aimed to compare SBP measurements obtained with Doppler ultrasonic flow detector (Doppler) versus high-definition oscillometry (HDO) in clinics and at home and to estimate the prevalence of situational hypertension in conscious, apparently healthy elderly dogs. ANIMALS: 122 apparently healthy elderly or geriatric dogs were prospectively recruited. PROCEDURES: Systolic blood pressure was obtained consecutively with Doppler and HDO techniques in a randomized order per dog, following a standardized protocol. An at-home measurement was advised for in-clinic hypertensive dogs (SBP ≥ 160 mmHg), also using both devices. RESULTS: Dual measurements were available in 102 dogs. Median SBP was 147.3 mmHg (range, 105 to 239 mmHg) for Doppler and 152.3 mmHg (range, 113 to 221 mmHg) for HDO. Forty-six percent (56/122) were hypertensive, of which 9% (11/122) were hypertensive with both methods. No significant difference was found between the 2 devices in the global study population or within the group of hypertensive dogs. Repeated at-home measurements were performed in 20/56 (35.7%) hypertensive dogs, resulting in a 10 and 26 mmHg lower median SBP value for Doppler and HDO, respectively (P > .05). In-clinic situational hypertension was presumed in 8/20 (40%) dogs. CLINICAL RELEVANCE: The choice of the noninvasive blood pressure device did not significantly impact SBP results, but large interindividual differences in SBP between techniques occurred. Situational hypertension was frequently observed in clinic.

Comparison of Four Arteries for Invasive Blood Pressure Measurements and Dixtal 2010 Oscillometric Values in Horses Anesthetized With Isoflurane: Does the Artery Matter?

This study evaluated the agreement between invasive blood pressure (IBP) values measured in three different arteries and by an oscillometric device (NIBP) with the ones from the transverse facial artery (FA). Six horses (424.2 ± 40.7 kg) were sedated with xylazine (0.6 mg/kg IV), induced with ketamine (2 mg/kg IV) and midazolam (0.1 mg/kg IV), and maintained with isoflurane (1.2 MAC) for 90 minutes in lateral recumbency. FA, auricular artery (AA), lateral digital artery (LDA), and metatarsal artery (MA) were catheterized, and a standard adult cuff was placed on the tail. IBP and NIBP values were recorded at 30, 45, 60, 75, and 90 minutes of anesthesia. Data were analyzed with Shapiro-Wilk and Repeated-Measures Bland-Altman. Values for FA (mm Hg) were 85.4 ± 10.3 for SAP, 70.6 ± 9.3 for MAP, and 58.5 ± 9.5 for DAP. Mean bias and 95% Limit of agreement (LOA) for AA were -1.7 (-29.0 to 25.6), 2.2 (-18.4 to 22.9), 1.9 (-18.2 to 22.0), for LDA: 1.4 (-25.1 to 27.8), 2.9 (-19.3 to 25.0), 2.3 (-18.4 to 22.9), for MA: -3.2 (-28.3 to 22.0), 2.7 (-16.6 to 22.1), 4.9 (-13.8 to 22.2), and for NIBP: -5.7 (-28.3 to 16.9), 7.9 (-9.5 to 25.3), 17.2 (-2.4 to 36.8), for SAP, MAP and DAP respectively. There is a reasonable bias for IBP values among the arteries evaluated, however a wide LOA, demonstrating the arteries are not interchangeable. NIBP method from Dixtal 2010 results in inaccurate blood pressure values in horses.

EVALUATION OF AGREEMENT BETWEEN OSCILLOMETRIC AND DIRECT BLOOD PRESSURE MEASUREMENTS IN ANESTHETIZED TIGERS (PANTHERA TIGRIS).

Noninvasive blood pressure measurement is commonly performed with oscillometry; however, this technique provides clinically helpful information only if it is representative of the gold standard. Agreement between direct and oscillometric blood pressure measurements were performed in 14 anesthetized, captive tigers (Panthera tigris). A cuff, placed around the tail base and connected to a multiparameter monitor, was used to measure arterial blood pressure oscillometrically and provided systolic, mean, and diastolic pressures. At the same time, direct blood pressures were obtained from a dorsal pedal arterial catheter, and the oscillometric and direct readings were considered paired data points. Agreement between the two methods was evaluated by Bland-Altman plots. All animals completed the study and provided 196 paired data points. The bias (mm Hg) for systolic, mean, and diastolic arterial pressures was -3.7, -0.8, and -1.6, respectively. Limits of agreement (mm Hg) for systolic, mean, and diastolic arterial pressures were -31 to 24, -29 to 27, and -29 to 26, respectively. Oscillometry provided an acceptable amount of readings within 10 and 20 mm Hg of the gold standard. The oscillometric technique provided reasonable agreement with direct measurements. Therefore, in the conditions used in this study, oscillometric blood pressure measured via the ventral coccygeal artery provided reasonable estimates of invasive blood pressure in anesthetized tigers.

Under pressure: A survey of Canadian veterinarians in the diagnosis and treatment of feline hypertension.

Objectives: The objectives of this study were to explore feline hypertension diagnostics and treatment practices among Canadian veterinarians and to identify barriers to recommending blood pressure monitoring in senior (> 7 y) feline wellness patients. Procedure: An online survey was developed and circulated by CommuniVET using email and social media. Results: A total of 114 Canadian veterinarians completed the survey. Most respondents indicated that they either do not recommend (n = 45; 39.5%) or occasionally recommend (n = 47; 41.2%) blood pressure monitoring in senior (> 7 y) feline wellness examinations. The most frequently reported barriers to recommending a blood pressure evaluation were the difficulty in interpreting results in stressed patients (n = 87; 76.3%), time involved in obtaining blood pressure (n = 73; 64.0%), and cost to the owner (n = 54; 47.4%). When faced with a patient diagnosed with a comorbidity commonly associated with hypertension, most respondents indicated that they always recommend (n = 38; 33.3%) or frequently recommend (n = 27; 23.7%) blood pressure monitoring. Most veterinarians' first line treatment for hypertension was amlodipine for primary (n = 81; 71.1%) and secondary (n = 39; 34.2%) hypertension. Conclusion: Most veterinarians did not routinely recommend blood pressure evaluation during senior feline wellness examinations. Although the frequency of recommendation for blood pressure monitoring appeared to be better in patients diagnosed with a comorbidity associated with hypertension, there was a substantial shortfall. Clinical relevance: This study identified the most common barriers to recommending blood pressure monitoring in senior feline wellness examinations. Normalizing blood pressure monitoring as part of a routine examination in senior feline patients may lead to increased intervention for hypertension and improved outcomes.

Sous pression : Une enquête auprès des vétérinaires canadiens sur le diagnostic et le traitement de l'hypertension féline. Objectifs: Les objectifs de cette étude étaient d'explorer les diagnostics et les pratiques de traitement de l'hypertension féline chez les vétérinaires canadiens et d'identifier les obstacles à la recommandation de la surveillance de la tension artérielle chez les patients félins âgés (> 7 ans). Procédure: Une enquête en ligne a été développée et diffusée par CommuniVET par courriel et sur les réseaux sociaux. Résultats: Au total, 114 vétérinaires canadiens ont répondu au sondage. La plupart des répondants ont indiqué qu'ils ne recommandaient pas (n = 45; 39,5 %) ou recommandaient occasionnellement (n = 47; 41,2 %) la surveillance de la tension artérielle lors des examens de santé des félins âgés (> 7 ans). Les obstacles les plus fréquemment signalés à la recommandation d'une évaluation de la tension artérielle étaient la difficulté d'interpréter les résultats chez les patients stressés (n = 87; 76,3 %), le temps nécessaire pour obtenir la tension artérielle (n = 73; 64,0 %) et le coût pour le propriétaire (n = 54; 47,4 %). Face à un patient diagnostiqué avec une comorbidité couramment associée à l'hypertension, la plupart des répondants indiquent recommander toujours (n = 38; 33,3 %) ou fréquemment (n = 27; 23,7 %) une surveillance de la pression artérielle. Le traitement de première intention de la plupart des vétérinaires contre l'hypertension était l'amlodipine pour l'hypertension primaire (n = 81; 71,1 %) et secondaire (n = 39; 34,2 %). Conclusion: La plupart des vétérinaires ne recommandent pas systématiquement l'évaluation de la pression artérielle lors des examens de santé des félins seniors. Bien que la fréquence de recommandation de la surveillance de la pression artérielle semble meilleure chez les patients diagnostiqués avec une comorbidité associée à l'hypertension, il y avait un manque à gagner important. Pertinence clinique: Cette étude a identifié les obstacles les plus courants à la recommandation d'une surveillance de la pression artérielle lors des examens de santé des félins seniors. La normalisation de la surveillance de la pression artérielle dans le cadre d'un examen de routine chez les patients félins âgés peut entraîner une intervention accrue pour l'hypertension et de meilleurs résultats.(Traduit par Dr Serge Messier).

Comparison between the Parks Medical Doppler and the Mano Médical Vet BP Doppler for recording indirect systemic blood pressure in conscious dogs.

Background: The acquisition of systemic blood pressure (SBP) provides valuable information regarding cardiovascular function and tissue perfusion in human and veterinary species. Aim: To evaluate the agreement between Parks Medical Doppler (PMD) and Mano Médical Vet BP (MMVBP) Doppler for assessing SBP in conscious dogs. Methods: 40 client-owned dogs were prospectively enrolled; SBP measurements were acquired by a single operator using the PMD and then the MMVBP. The mean of five consecutive measurements for each device was classified according to target organ damage (TOD) risk scores (1: <140 mmHg; 2: 140-160 mmHg; 3: 160-180 mmHg; 4: ≥ 180 mmHg). Results: Total mean SBP for the devices was not statistically different (p = 0.77). However, the Bland-Altman analysis revealed wide limits of agreement (LoA), with MMVBP slightly underestimating SBP compared to PMD (bias = -0.6 mmHg, 95% LoA: -26.3 to 25.09). Both devices correlated well ( r = 0.8269; p < 0.0001) and had identically acceptable intra-observer repeatability (coefficients of variation = 4.09% for MMVBP and 3.86% for PMD). Four dogs (10%) had a TOD score of 3 by one device but scored <3 with the other. Conclusion: A good agreement and correlation was observed between the PMD and the MMVBP, suggesting that both devices can be used interchangeably for assessment of SBP in conscious dogs. The wide LoA observed between both devices was most likely associated with intraindividual variability in SBP over time.

Rodent Thermoregulation: Considerations for Tail-Cuff Blood Pressure Measurements.

Noninvasive blood pressure measurement devices have gained popularity in recent years as an alternative to radiotelemetry and other invasive blood pressure measurement techniques. While many factors must be considered when choosing a measurement method, specific variables should be evaluated when using a tail-cuff blood pressure technique. Rodents have complex and dynamic thermal biology processes that involve fluctuating vasomotor tone of the tail. This and other factors that affect vascular tone, such as the autonomic response to stress, significantly affect peripheral blood flow. Awareness and consideration of thermoregulatory states and vasomotor tone can increase success and decrease variability when measuring blood pressure measurements using a tail-cuff measurement technique.

'The Mercury Challenge': feline systolic blood pressure in primary care practice - a European survey.

OBJECTIVES: The aim of this study was to collect data from a substantial number of older cats having their systolic blood pressure (SBP) measured in a variety of clinical practices, to describe the findings and assess variables that affected the duration of assessment and the values obtained. METHODS: An international (European-based) multicentre convenience sample survey of cats ⩾7 years of age attending veterinary clinics and having SBP measured as part of their clinical assessment. Information gathered included details of the cat, concomitant disease(s) or therapies, SBP results, device used, time taken to assess SBP and the demeanor of the cat. RESULTS: Useable data were available from 8884 cats aged 7-26 years, from 811 clinics across 16 countries. The device used to measure SBP was Doppler in 47.4% and oscillometry in 48.5%. The demeanor of the cat was reported to be calm in 45.7%, anxious in 41.9% and nervous in 8.9%; and the duration of assessment was reported to be <5 mins in 50.4%, 5-10 minutes in 41.7% and >10 mins in 7.9%. Concomitant chronic kidney disease (CKD) was reported in 21.8%, hyperthyroidism in 12.0% or both in 3.1%. The median SBP was 150 mmHg (range 80-310), with 18.6% classified as hypertensive (SBP 160-179 mmHg) and 21.1% as severely hypertensive (SBP ⩾180 mmHg). The measured SBP was significantly affected by the cat's demeanor, duration of SBP assessment, presence of CKD and/or hyperthyroidism, the cat's sex and age, and the presence of concomitant therapy. The duration of SBP assessment was significantly affected by the cat's demeanor. CONCLUSIONS AND RELEVANCE: In veterinary clinics, SBP can be measured in most cats within a short period of time using either Doppler or oscillometric equipment. The presence of CKD or hyperthyroidism was associated with significantly higher SBP values, and anxious or nervous cats had higher SBP values and took longer to obtain SBP assessments.

Agreement of caudal aortic arterial blood pressure with oscillometry using two cuff widths placed on the thoracic or pelvic limbs of sevoflurane-anesthetized rabbits.

OBJECTIVE: To evaluate agreement with central systemic arterial pressure of an oscillometer and two cuff widths placed on the thoracic or pelvic limbs. STUDY DESIGN: Prospective experimental study. ANIMALS: A group of nine New Zealand White rabbits weighing 3.5 ± 0.3 kg. METHODS: Rabbits were sedated with dexmedetomidine and midazolam, then anesthetized with ketamine and sevoflurane. The femoral artery was surgically exposed and a 20 gauge, 5 cm catheter inserted to measure systolic (SAP), mean (MAP) and diastolic (DAP) blood pressure at the iliac artery and caudal aorta junction. Adjustments of vaporizer dial and dobutamine infusion provided a range of invasive blood pressure (IBP). Two measurements of IBP were recorded during the oscillometer cycling phase, and the mean value was used in analyses. Oscillometer cuffs of bladder width 2.0 cm (S1) and 2.5 cm (S2) were placed proximal to the carpus and tarsus. Cuff width to circumference ratio was calculated. Oscillometer SAP, MAP and DAP were paired with corresponding IBP values. Agreement was assessed using linear mixed models (p < 0.05). RESULTS: Cuff ratios for both limbs were 41% (S1 cuff) and 50% (S2 cuff) and 122-139 paired observations were obtained. There was significant limb × cuff interaction with SAP and MAP. The oscillometer overestimated SAP and MAP on the pelvic limb and underestimated SAP and MAP on the thoracic limb. For SAP, the oscillometer overestimated by constant bias (-19 ± 2 mmHg) and proportional bias (0.28 ± 0.02 mmHg per 1 mmHg increase). For MAP, the oscillometer underestimated by constant bias (4 ± 2 mmHg) and was worse with S2 on the thoracic limb. Overestimation was similar between cuffs on the pelvic limb. For DAP, the oscillometer underestimated by constant bias (15 ± 2 mmHg). CONCLUSIONS AND CLINICAL RELEVANCE: Cuff S1 on the thoracic limb provided best estimation of MAP.

Validation of oscillometric blood pressure measurement using a Datex S/5 Compact multiparameter monitor in anaesthetized adult dogs.

OBJECTIVE: To compare noninvasive (NIBP) with invasive blood pressure (IBP) measurements from a Datex S/5 Compact monitor in anaesthetized adult dogs, and to evaluate it according to the American College of Veterinary Internal Medicine (ACVIM) and the Association for the Advancement of Medical Instrumentation (AAMI) criteria. STUDY DESIGN: Prospective clinical study. ANIMALS: A group of 34 client-owned adult dogs. METHODS: Dogs were anaesthetized for different surgical procedures using different anaesthetic protocols. IBP was measured using a catheter placed in a dorsal pedal artery. A blood pressure cuff was placed over the contralateral dorsal pedal artery for NIBP measurement. Data were recorded using the Datex iCollect program, and paired readings were matched every 3 minutes for 60 minutes. Bland-Altman and error grid analyses were used to estimate the agreement between IBP and NIBP measurements, and its clinical significance, respectively. Data were reported as mean bias [lower, upper limits of agreement (LoA)]. RESULTS: The Datex S/5 monitor conformed to most ACVIM criteria. The correlation coefficient was less than 0.9 for systolic, diastolic, and mean arterial pressures (MAP). The best agreement between the noninvasive and invasive methods was observed for MAP, with LoA (-17 to 13 mmHg) and higher percentage of NIBP readings within 5 (55.6%), 10 (81.7%) and 20 (98.6%) mmHg of the IBP values. The Datex S/5 NIBP technology did not meet the AAMI validation criteria and less than 95% of the paired measurements were found within the green zone of the error grid analysis. CONCLUSIONS AND CLINICAL RELEVANCE: The Datex S/5 monitor conformed to most ACVIM criteria but not with the more rigorous AAMI standards. Despite good agreement between IBP and NIBP for MAP measurements, care must be taken when using this device to guide therapeutic interventions of blood pressure in anaesthetized healthy adult dogs.

Evaluation of noninvasive blood pressure in anesthetized horses: Bias, limits of agreement, and comparative detection of a predetermined mean blood pressure warranting treatment.

Oscillometric blood pressure monitoring may be a practical tool for short procedures or those performed outside of the operating room. Oscillometric and direct blood pressure values in 30 juvenile and adult horses in a clinical setting using mixed effect models were compared. The limits of agreement and percentage errors were also calculated. We evaluated the sensitivity and false positive rate for the oscillometric method to trigger an intervention for treating blood pressure [direct mean arterial pressure (MAP) < 70 mmHg]. Oscillometric MAP and diastolic arterial pressure (DAP) differed from direct values (P < 0.001); systolic arterial pressure (SAP) did not (P = 0.08). Wide limits of agreement were observed. Percentage errors were smaller for SAP (39%) than for MAP and DAP (48% and 72%). The oscillometric monitor indicated there was a requirement for blood pressure treatment with a true positive rate of 82%, consequently, it failed 18% of the times. The false positive rate (unnecessary treatment) was 55%.

Évaluation non invasive de la pression artérielle chez des chevaux anesthésiés: biais, limites d'accord et détection comparative d'une pression artérielle moyenne prédéterminée justifiant un traitement. La surveillance oscillométrique de la pression artérielle peut être un outil pratique pour les procédures courtes ou celles effectuées hors de la salle d'opération. Les valeurs oscillométriques et directes de la pression artérielle chez 30 chevaux juvéniles et adultes en milieu clinique ont été comparées à l'aide de modèles à effets mixtes. Les limites d'accord et les pourcentages d'erreurs furent également calculés. Nous avons évalué la sensibilité et le taux de faux positifs de la méthode oscillométrique pour déclencher une intervention pour le traitement de la pression artérielle [pression artérielle moyenne directe (PAM) < 70 mmHg]. La PAM oscillométrique et la pression artérielle diastolique (PAD) différaient des valeurs directes (P < 0,001); mais pas la pression artérielle systolique (PAS) (P = 0,08). De larges limites d'accord ont été observées. Les pourcentages d'erreurs étaient plus faibles pour PAS (39 %) que pour PAM et PAD (48 % et 72 %). Le moniteur oscillométrique a indiqué qu'il y avait une exigence pour un traitement de la pression artérielle avec un taux de vrais positifs de 82 %, par conséquent, il a échoué 18 % des fois. Le taux de faux positifs (traitement inutile) était de 55 %.(Traduit par Dr Serge Messier).

Agreement between invasive and oscillometric arterial blood pressure measurement using a high-definition oscillometric device in normotensive New Zealand White rabbits using two different anaesthetic protocols.

OBJECTIVE: To use American College of Veterinary Internal Medicine (ACVIM) criteria to evaluate a high-definition oscillometric (HDO) blood pressure monitoring device versus invasive blood pressure (IBP) measurement in normotensive rabbits anaesthetized with two different anaesthetic protocols. STUDY DESIGN: Prospective experimental study. ANIMALS: A group of 20 healthy adult New Zealand White rabbits weighing 4.36 ± 0.37 kg (mean ± standard deviation). MATERIALS AND METHODS: Rabbits were premedicated with butorphanol 0.5 mg kg-1 and midazolam 0.5 mg kg-1 subcutaneously (SC, group BMA) or ketamine 25 mg kg-1 and medetomidine 0.4 mg kg-1 SC (group KM). Anaesthesia was induced with alfaxalone administered intravenously (group BMA) or isoflurane by face mask (group KM) and maintained with isoflurane in oxygen. IBP was measured from the central auricular artery. The cuff for the HDO monitor was placed distal to the left elbow and distal to the left tarsus. Agreement between invasive and HDO measurements was evaluated using Bland-Altman method. RESULTS: In group KM there was better agreement between the HDO device and IBP when the cuff was placed on the thoracic limb, with 100% and 91% of the readings for mean (MAP) and diastolic arterial pressure (DAP), respectively, within 10 mmHg of the IBP measurements. The agreement, although worse, also met the ACVIM criteria for systolic arterial pressure (SAP; 53% of the readings within 10 mmHg). In group BMA, the device met the criteria with the cuff on the thoracic limb only, and only for MAP and DAP (73% and 75% of the measurements within 10 mmHg of the IBP, respectively) but not for SAP (12%). CONCLUSION AND CLINICAL RELEVANCE: The HDO device met most of the ACVIM criteria for noninvasive blood pressure measurement in anaesthetized rabbits, specifically when the cuff was placed distal to the elbow and the anaesthetic protocol included ketamine and medetomidine.

Evaluation of coccygeal and radial artery Doppler blood pressure measurements in sick cats with and without abnormalities in tissue perfusion.

OBJECTIVE: To compare systolic blood pressure measured by Doppler (SBP) taken from the coccygeal artery versus common digital branch of the radial artery in cats with normal and poor perfusion parameters. DESIGN: Prospective, observational study. SETTING: University Teaching Hospital. ANIMALS: Eighty-five cats presenting to the emergency service for which prior emergency treatment was not received and a blood pressure was indicated on triage. INTERVENTIONS: Systolic blood pressure was measured by Doppler using the radial and coccygeal arteries. Cats were categorized as having normal or poor tissue perfusion based on physical examination. MEASUREMENTS AND MAIN RESULTS: Agreement was poor between coccygeal and radial SBP overall with absolute and relative bias (95% limits of agreement) of 23 (-51 to 96) mm Hg and 16% (-38% to 69%), respectively. In cats with poor perfusion, the agreement was absolute bias = 28 mm Hg and relative bias = 22% and with normal perfusion absolute bias = 22 mm Hg, and relative bias = 12%. The median (interquartile range) coccygeal SBP was significantly different from the radial SBP 141 (50) mm Hg versus 120 (45) mm Hg, P < 0.001. In multivariate linear regression, heart rate was negatively associated with coccygeal SBP (r2  = 0.088, P = 0.049), and pale mucous membrane color (P = 0.034) and poor pulse quality (P = 0.007) were independently associated with lower radial SBP (r2  = 0.18). CONCLUSIONS: Median coccygeal SBP is significantly greater than radial SBP in sick cats with both normal perfusion and hypoperfusion. Agreement between coccygeal and radial SBP is poor in cats and cannot be used interchangeably. As clinically significant differences exist between sites, the authors recommend obtaining SBP from both sites initially and choosing to monitor and trend changes with the one site that correlates most with physical examination findings.