Validation of noninvasive blood pressure equipment: which peripheral artery is best for comparison studies in dogs?

OBJECTIVES: 1) To determine which peripheral artery commonly used for invasive arterial blood pressure (IBP) monitoring yields the least bias when compared with noninvasive blood pressure (NIBP) values obtained at the antebrachium of the dog, and 2) to identify and describe differences in systolic (SAP), mean (MAP) and diastolic arterial pressures (DAP) among different anatomical locations. STUDY DESIGN: Prospective experimental study. ANIMALS: Twenty adult hound dogs weighing 24.5 ± 1.1 kg (mean ± standard deviation). METHODS: Four peripheral arteries-dorsal pedal, median caudal, intermediate auricular and superficial palmar arteries-were catheterized with 20 gauge, 3.8 cm catheters. One NIBP cuff was placed in the middle third of the antebrachium. Four sets of IBP and NIBP measurements were simultaneously collected every 2 minutes. A linear mixed model was performed to analyze the collected data. RESULTS: IBP values varied depending on the arterial catheterization site. The difference was greater for SAP. NIBP measured at the antebrachium had the best agreement with IBP measured at the median caudal artery. CONCLUSION AND CLINICAL RELEVANCE: IBP varies among anatomical locations. The smallest bias and narrowest limits of agreement were obtained at the median caudal artery, providing the best overall agreement with the equipment studied. The median caudal artery may be the preferable anatomical location for clinical comparison studies between IBP and NIBP in dogs when the cuff is on the antebrachium.

Agreement between two oscillometric blood pressure technologies and invasively measured arterial pressure in the dog.

OBJECTIVES: To compare two commonly used oscillometric technologies for obtaining noninvasive blood pressure (NIBP) measurements and to determine if there is a difference in agreement between these systems and invasive blood pressure (IBP) measurements. STUDY DESIGN: Prospective, experimental study. ANIMALS: Twenty adult laboratory dogs. METHODS: Each dog was anesthetized and its median caudal artery catheterized for IBP monitoring. An NIBP cuff was placed in the middle third of the antebrachium and attached to either monitor-1 or monitor-2. Four pairs of concurrent NIBP and IBP measurements were recorded with each monitor. Agreement between IBP and NIBP measurements was explored using Bland-Altman analysis, as well as the American College of Veterinary Internal Medicine (ACVIM) and Association for the Advancement of Medical Instrumentation (AAMI) guidelines for the validation of NIBP devices. RESULTS: Both NIBP technologies produced results that met the ACVIM and AAMI guidelines for the validation of NIBP devices. For monitor-1, analyses of agreement showed biases of 0.2 mmHg [95% limits of agreement (LoA) -11.8 to 12.3 mmHg] in systolic arterial pressure (SAP) values, -2.6 mmHg (95% LoA -14.4 to 9.1 mmHg) in diastolic arterial pressure (DAP) values, and -2.5 mmHg (95% LoA -12.7 to 7.3 mmHg) in mean arterial pressure (MAP) values. For monitor-2, analyses of agreement showed biases of 3.4 mmHg (95% LoA -8.7 to 15.5 mmHg) in SAP values, 2.2 mmHg (95% LoA -6.6 to 10.9 mmHg) in DAP values, and 1.6 mmHg (95% LoA -5.9 to 8.9 mmHg) in MAP values. CONCLUSIONS AND CLINICAL RELEVANCE: Multi-function monitors can contain components from various manufacturers. Clinicians should consider whether these have been validated in the species to be monitored. Both of the technologies studied here seem appropriate for use in dogs.

Comparison of blood pressure measurements of anesthetized dogs obtained noninvasively with a cylindrical blood pressure cuff and an anatomically modified conical blood pressure cuff.

OBJECTIVE: To compare blood pressure measured noninvasively with an oscillometric device that involved use of a novel conical cuff and a traditional cylindrical blood pressure cuff. ANIMALS: 17 adult hound-type dogs. PROCEDURES: Dogs were anesthetized, and a 20-gauge, 1.5-inch catheter was inserted in the median sacral artery. The catheter was attached to a pressure transducer via fluid-filled noncompliant tubing, and direct blood pressure was recorded with a multifunction monitor. A specially fabricated conical cuff was placed on the antebrachium. Four sets of direct and indirect blood pressure measurements were simultaneously collected every 2 minutes. Four sets of measurements were then obtained by use of a cylindrical cuff. RESULTS: The cylindrical cuff met American College of Veterinary Internal Medicine consensus guidelines for validation of indirect blood pressure measurements for mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP). The conical cuff met the consensus guidelines for difference of paired measurements, SD, and percentages of measurements within 10 and 20 mm Hg of the value for the reference method, but it failed a correlation analysis. In addition, although bias for the conical cuff was less than that for the cylindrical cuff for SAP, MAP, and DAP measurements, the limits of agreement for the conical cuff were wider than those for the cylindrical cuff for SAP and MAP measurements. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of results of this study, use of a conical cuff for oscillometric blood pressure measurement cannot be recommended.

Comparison of directly measured arterial blood pressure at various anatomic locations in anesthetized dogs.

OBJECTIVE: To determine whether directly measured arterial blood pressure differs among anatomic locations and whether arterial blood pressure is influenced by body position. ANIMALS: 33 client-owned dogs undergoing anesthesia. PROCEDURES: Dogs undergoing anesthetic procedures had 20-gauge catheters placed in both the superficial palmar arch and the contralateral dorsal pedal artery (group 1 [n = 20]) or the superficial palmar arch and median sacral artery (group 2 [13]). Dogs were positioned in dorsal recumbency, and mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP) were recorded for both arteries 4 times (2-minute interval between successive measurements). Dogs were positioned in right lateral recumbency, and blood pressure measurements were repeated. RESULTS: Differences were detected between pressures measured at the 2 arterial sites in both groups. This was especially true for SAP measurements in group 1, in which hind limb measurements were a mean of 16.12 mm Hg higher than carpus measurements when dogs were in dorsal recumbency and 14.70 mm Hg higher than carpus measurements when dogs were in lateral recumbency. Also, there was significant dispersion about the mean for all SAP, DAP, and MAP measurements. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that arterial blood pressures may be dependent on anatomic location and body position. Because this may affect outcomes of studies conducted to validate indirect blood pressure measurement systems, care must be used when developing future studies or interpreting previous results.