Ankle-brachial blood pressure differences before and during anesthesia

ABSTRACT

BACKGROUND: In surgeries involving the upper extremities and breast, the blood pressure is frequently measured at the ankles. As the blood pressure is used as a pain indicator in the full surgical anesthesia, the ankle blood pressure higher than the brachial blood pressure may be misinterpreted by the anesthesiologist, in determining the depth of the anesthesia. This paper investigated whether the ankle blood pressure is significantly higher than the brachial blood pressure before the anesthesia induction, during induction, and after tracheal intubation. METHODS: Two hundred seventeen patients requiring general anesthesia for elective surgery were included in this study. Ankle and brachial blood pressure were simultaneously measured before the anesthesia induction, during induction, and after tracheal intubation. RESULTS: The ankle blood pressure was higher than the brachial blood pressure before induction, during induction, and after tracheal intubation. Ankle-brachial blood pressure differences were significantly higher before induction and after intubation as compared to that during induction. The correlation coefficient between the systolic ankle-brachial blood pressure difference before induction and that after tracheal intubation was 0.623. In 33 child patients with an ankle-brachial blood pressure index > or =1 before induction, there were no significant differences in the ankle-brachial blood pressure during induction. The brachial systolic blood pressure could be predicted by simple and multiple regression equations (R2 = 0.349-0.828). CONCLUSIONS: The results of the study suggest that the anesthesiologists need to consider the ankle-brachial blood pressure differences in monitoring the anesthesia, in cases where the brachial blood pressure cannot be measured during surgery.