Can we use the ankle non-invasive blood pressure during otolaryngologic surgery: an observational study

INTRODUCTION: In otolaryngologic surgery, ankle is frequently used for monitoring anesthesia in place of brachial when the patient doesn´t need invasive arterial cannulation. If there is a clinically useful and Predictable link between the two readings in hemodynamic normal patient, this difference during otolaryngologic surgery, was not evaluated. We aimed to investigate the reliability and the acceptability of non invasive blood pressure measurements at the ankle compared to those obtained concurrently at the arm during otolaryngologic surgery. METHODS: Eighty ASA grade I and II patients who had to be operated under general anesthesia were taken as subjects for our study. Blood pressures were measured simultaneously in the 2 limbs before induction and then every 10 minutes until the end of the surgical procedure. Readings were initiated concurrently. Statistical analysis was performed with PASW Statistics 13. RESULTS: There were 41 males (51.2 %) and 39 females (48.8 %). Bland-Altman analysis of mean difference between the ankle and arm (95 % limits of agreement) was -11.47 (- 23.77 to 0.82) mmHg for systolic blood pressure (SBP), -7.89 (-19.16 to 3.36) mmHg for diastolic blood pressure (DBP) and - 9.09 (18.19 to 0.00) mmHg for mean arterial pressure (MAP). Non-parametric analysis showed that 67.5 % of SBP, 46.2 % of DBP and 56.2 % of MAP measurements differed by > 10mmHg. CONCLUSION: Ankle BP cannot be used routinely in otolaryngological surgery. Although, the ankle can be used as an alternative where the arm cannot be used taking into account a difference.