Abstract
Introduction: The importance of monitoring blood pressure and avoiding hypotension in anaesthetized horses is well established. There are no studies in horses assessing agreement of blood pressure measured invasively at different peripheral sites in clinical cases.
Methods: The aim was to determine agreement between invasive blood pressure measurement in three peripheral arteries in anaesthetized horses (ASA 1-2) undergoing routine surgical procedures.
Prospective randomized balanced incomplete block design using 18 client-owned horses. Invasive blood pressure was measured simultaneously via two catheters placed in one of three combinations: 1) transverse facial and facial artery; 2) transverse facial and metatarsal and 3) facial and metatarsal artery, which were randomly assigned to six horses each. At each sample time, systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured concurrently from each artery and the mean of three consecutive measurements was recorded. Heart rate and the use of dobutamine was also recorded. Bland Altman analysis was used to assess agreement between sites.
Results: A total of 162 paired measurements were obtained. All paired measurements showed a random pattern of disagreement. The widest limit of agreement of 56.1 mmHg was documented for SAP between the facial artery and metatarsal artery. The smallest limit of agreement was 16.5 mmHg for the MAP between the transverse facial and the metatarsal artery.
Conclusion: In conclusion, there is poor agreement and random disagreement with SAP, MAP and DAP across all peripheral sites used in this study. The levels of disagreement were unacceptable and measurements from these sites cannot be used interchangeably.