Effect of limb and cuff positioning on measurement of arterial blood pressure with an oscillometry device (PetMAP) in anaesthetized cats
Effect of limb and cuff positioning on measurement of arterial blood pressure with an oscillometry device (PetMAP) in anaesthetized cats
Open access
In our edition of: Aug 2024
In our categories of: small animals
our summary:
Franchino, G., Fordyce, P. and Adami, C. (2024) Effect of limb and cuff positioning on measurement of arterial blood pressure with an oscillometry device (PetMAP) in anaesthetized cats. The Veterinary Journal, 305, 106137.
The objective of this study was to determine the effects of deviation of the limb from the standard position, at the level of the heart, on arterial blood pressure (ABP), measured with PetMAP, in anaesthetised cats. The authors hypothesised that raising or lowering the limb by 5 cm with respect to the heart level would result in underestimation or overestimation of ABP values respectively.
Client-owned cats undergoing general anaesthesia for elective surgery at a UK veterinary hospital that had an American Society of Anaesthesiologists classification of two or less, and no previous diagnosis of a condition that could result in hypotension or hypertension, were eligible for inclusion in the study.
The same PetMAP device was used for all the study cats. For both the thoracic and pelvic limbs, ABP was measured at three different heights – baseline measurement at the level of the heart, with measurements below (-5) and above (+5) the level of the heart obtained by subtracting and adding five cm to the baseline height, respectively. Two measurements were taken at each height with the mean value used for data analysis.
Twenty-nine cats were enrolled in the study. There were no differences in end-tidal isoflurane concentrations during baseline measurement or those recorded at either 5 cm above or 5cm below the heart. ABP measured above the heart was consistently lower than baseline for both pelvic and thoracic limbs. There were no differences between baseline values and those measured below the heart. Systolic ABP readings at the pelvic limb were consistently higher that those at the thoracic limb in all three positions, there were no differences between the mean and diastolic ABP values measured at the thoracic and pelvic limbs.
Limitations of the study are the results did not report data for individual cats, that the results from this single device may not be generalisable to other devices and that there was no direct comparison between oscillometric and invasive ABP measurements.
This study provides some evidence that limb position relative to the heart can affect blood pressure measurement, and that raising the limb by 5 cm above the heart can result in a clinically significant underestimation of arterial blood pressure. Veterinary practitioners should bear this in mind when positioning the limbs during procedures.
The following may also be of interest:
inFOCUS: Understanding the barriers to blood pressure assessment in cats [RCVS Knowledge] [online] Available from: https://infocus.rcvsknowledge.org/understanding-the-barriers-to-blood-pressure-assessment-in-cats/ [Accessed 19 August 2024]
inFOCUS: Feline blood pressure measurement: when is it needed? [RCVS Knowledge] [online] Available from: https://infocus.rcvsknowledge.org/feline-blood-pressure-measurement-when-is-it-needed/ [Accessed 19 August 2024]
inFOCUS: ISFM consensus guidelines on the diagnosis and management of hypertension in cat [RCVS Knowledge] [online] Available from: https://infocus.rcvsknowledge.org/isfm-consensus-guidelines-on-the-diagnosis-and-management-of-hypertension-in-cats/ [Accessed 19 August 2024]
ISFM. Practical recommendations on the measurement of indirect blood pressure in cats [International Cat Care] [online] Available from: https://icatcare.org/app/uploads/2020/05/ISFM-BP-recommendations.pdf [Accessed 19 August 2024]
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