Comparison of Four Arteries for Invasive Blood Pressure Measurements and Dixtal 2010 Oscillometric Values in Horses Anesthetized With Isoflurane: Does the Artery Matter?
Authors: Midon Monica, Yamada Diego I, Zangirolami Filho Darcio, Simionato Giulia C, Feringer Junior Walter H, Conde Gabriel, Hofmeister Erik H
Journal: Journal of equine veterinary science
Summary
# Editorial Summary During isoflurane anaesthesia, invasive blood pressure measurements obtained from the auricular, lateral digital, and metatarsal arteries show reasonable mean agreement with transverse facial artery values (bias ranging from −3.2 to 2.9 mm Hg across systolic, mean, and diastolic pressures), yet the wide limits of agreement (±18–28 mm Hg) indicate these sites cannot be reliably used interchangeably in clinical practice. Six horses maintained on 1.2 MAC isoflurane had catheters placed in all four arteries simultaneously, with blood pressure recorded at five timepoints over 90 minutes, alongside non-invasive oscillometric measurements from a tail cuff using a Dixtal 2010 device. The oscillometric method proved substantially less reliable than any invasive arterial site, particularly for diastolic pressure readings, which diverged by as much as 17.2 mm Hg (limits of agreement −2.4 to 36.8 mm Hg). For anaesthetists and equine practitioners requiring accurate haemodynamic monitoring during prolonged procedures, the transverse facial artery remains the most dependable single-site choice; whilst other arteries may serve as alternatives when facial access is compromised, clinicians must recognise that switching between sites introduces significant measurement uncertainty and oscillometric devices should not be relied upon for precise pressure assessment in isoflurane-anaesthetised horses.
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Practical Takeaways
- •If using invasive blood pressure monitoring during equine anesthesia, the artery selected matters—do not assume measurements from different sites are equivalent, even if bias appears small
- •The Dixtal 2010 oscillometric device is unreliable for blood pressure monitoring in anesthetized horses and should not be used as a sole monitoring method, particularly for diastolic values
- •If arterial catheterization is performed for anesthesia monitoring, stick with the transverse facial artery as your reference standard rather than switching between sites
Key Findings
- •Mean bias for invasive blood pressure among arteries ranged from -3.2 to 2.9 mm Hg, but 95% limits of agreement were wide (±13.8 to ±29.0 mm Hg), indicating arteries are not interchangeable
- •Transverse facial artery measured mean SAP 85.4 ± 10.3, MAP 70.6 ± 9.3, and DAP 58.5 ± 9.5 mm Hg during isoflurane anesthesia
- •Non-invasive blood pressure (Dixtal 2010) showed significant inaccuracy compared to invasive measurements, particularly for diastolic pressure (bias +17.2 mm Hg with wide LOA -2.4 to +36.8)