Comparison of two species-specific oscillometric blood pressure monitors with direct blood pressure measurement in anesthetized cats

Objective: To compare the performance of 2 species-specific oscillometric blood pressure (OBP) monitors (petMAP_classic and petMAP_graphic ) with direct blood pressure measurement in anesthetized cats.

Design: Prospective, experimental study.

Setting: Veterinary teaching hospital.

Animals: Eight adult cats (3.2-5.5 kg).

Interventions: During isoflurane anesthesia, OBP cuffs were placed on the thoracic limb and on the base of the tail while invasive blood pressure (IBP) was recorded from a dorsal pedal artery. End-tidal isoflurane concentrations, with or without intravenous dopamine (n = 8), norepinephrine (n = 1), or phenylephrine (n = 1) were adjusted to change invasive mean arterial pressure (MAP) between 40 to 100 mm Hg. Data were analyzed by the Bland-Altman method and 4-quadrant plots.

Measurements and main results: Mean biases and limits of agreement (LOA: ± 1.96 SD) (mm Hg) recorded between the petMAP_classic (thoracic limb) and IBP for systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and MAP were 4.2 ± 28.5, -6.1 ± 13.2, and -1.9 ± 14.6, respectively; mean biases and LOA (mm Hg) recorded with the tail cuff were 7.2 ± 31.3 (SAP), -6.1 ± 11.6 (DAP), and -1.1 ± 11.7 (MAP). Mean biases and LOA (mm Hg) between petMAP_graphic (thoracic limb) and IBP were 7.7 ± 27.0 (SAP), -4.3 ± 11.5 (DAP), 0.2 ± 13.0 (MAP); values recorded with the tail cuff were 10.9 ± 29.6 (SAP), -4.4 ± 11.7 (DAP), and -0.1 ± 12.1 (MAP). Concordance rates after excluding arterial pressure changes ≤ 5 mm Hg was ≥ 93% for both devices.

Conclusions: Although both OBP monitors provide unacceptable SAP estimations, MAP values derived from both monitors and DAP measured by the petMAP_graphic result in acceptable agreement with the reference method according to the Association for the Advancement of Medical Instrumentation (mean bias ≤ 5 mm Hg with LOA ≤ ± 16 mm Hg). Both monitors provide acceptable trending ability for SAP, DAP, and MAP.