Pulse pressure variation and systolic pressure variation in horses undergoing general anesthesia

Changes in arterial pressure due to respiratory phases have been used to predict fluid responsiveness in a number of species and pulse pressure variation (PPV) and systolic pressure variation (SPV) are commonly used. The relationship between PPV and SPV has not been described in horses.

To describe and compare PPV and SPV values of horses under general anesthesia.

Twenty-six horses undergoing general anesthesia and receiving mechanical ventilation were enrolled in the study. Recordings of maximal and minimal values of pulse pressure and systolic pressure were calculated every 15 minutes throughout surgery.

Initial PPV was 15.6% (7.9, 33.8) and decreased over the first 30 minutes to 10.7 ± 7.2% (P = 0.03). Initial SPV was 10.3 ± 2.6% and decreased over the first 30 minutes to 7.3 ± 3.3% (P = 0.004). PPV and SPV had a correlation coefficient of 0.52 (P < 0.0001) and a 95% limits of agreement from -7.1% to 14.4%.

PPV and SPV measurements in horses do not have strong agreement.