title: Ankle-brachial blood pressure differences in the beach-chair position of the shoulder surgery.
abstract: BACKGROUND
  During shoulder surgery, blood pressure is frequently measured at the ankle. Anesthetic complications may result when ankle blood pressure is higher than brachial blood pressure and anesthesiologists misinterpret ankle blood pressure as brachial blood pressure. Therefore, we investigated whether ankle blood pressure is significantly higher than brachial blood pressure before anesthesia induction, during induction, after tracheal intubation, before beach chair position, and in the beach chair position.
  
  
  METHODS
  Thirty patients requiring general anesthesia for shoulder surgery were included in this study. Ankle and brachial blood pressure were simultaneously measured before induction, during induction, after intubation, before beach chair position, and in the beach chair position.
  
  
  RESULTS
  Ankle blood pressure was higher than brachial blood pressure before induction, during induction, after intubation, before beach chair position, and in the beach chair position. Ankle-brachial blood pressure differences in the beach chair condition were much higher than in four other conditions. The correlation coefficient between mean ankle-brachial blood pressure differences before the beach chair position and mean ankle-brachial blood pressure differences in the beach chair position was 0.616. Brachial systolic blood pressure could be predicted by regression equations (R(2) = 0.306-0.771).
  
  
  CONCLUSIONS
  These results suggest that anesthesiologists should consider these ankle-brachial blood pressure differences when monitoring anesthesia in the beach chair position.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors.forename: Jae Chan
authors.initials: JC
authors.lastname: Choi
authors.forename: Jong-Hyuk
authors.initials: JH
authors.lastname: Lee
authors.forename: Young-Don
authors.initials: YD
authors.lastname: Lee
authors.forename: Soon Yul
authors.initials: SY
authors.lastname: Kim
authors.forename: Sei-Jin
authors.initials: SJ
authors.lastname: Chang
keywords: Ankle blood pressure; Ankle-brachial blood pressure index; Beach chair position; Blood pressure; Brachial blood pressure; Shoulder surgery