title: Increase in airway pressure resulting from prone position patient placing may predict intraoperative surgical blood loss.
abstract: METHODS
  Prospective study on intraoperative blood loss during lumbar spine surgery.
  
  
  OBJECTIVE
  To evaluate the relationship between airway pressure change due to the patient's prone position and intraoperative blood loss during lumbar spine surgery.
  
  
  BACKGROUND
  A prone position may increase abdominal pressure. Changes in abdominal pressure may influence airway pressure and cause intraoperative blood loss as a result of epidural venous congestion.
  
  
  METHODS
  Patients undergoing lumbar spine surgery were placed in a prone position after the administration of general anesthesia. Peak airway pressure, plateau pressure, mean blood pressure, and heart rate were measured 5 minutes after anesthesia induction and 15 minutes after being placed in a prone position. Intraoperative blood loss was measured at the end of surgery.
  
  
  RESULTS
  Mean peak airway pressure was 13.7 ± 1.8 mm Hg while in a supine position and increased to 15.1 ± 2.5 mm Hg after placement in the prone position (P = 0.002). Plateau pressure was 12.6 ± 2.5 mm Hg while in a supine position and increased to 14.1 ± 1.9 mm Hg after placement in a prone position (P = 0.0002). Intraoperative blood loss was correlated with peak (R2 = 0.405) and plateau (R2 = 0.489) airway pressure changes.
  
  
  CONCLUSIONS
  Increase in airway pressure resulting from placement into a prone position may predict intraoperative surgical blood loss.
authors: Department of Anesthesiology and Pain Medicine and Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Republic of Korea.
authors: Jae Chul
authors: JC
authors: Koh
authors: Jong Seok
authors: JS
authors: Lee
authors: Dong Woo
authors: DW
authors: Han
authors: Satbyul
authors: S
authors: Choi
authors: Chul Ho
authors: CH
authors: Chang
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D004824:Epidural Space / Q000098:blood supply; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D007432:Intraoperative Period; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D016684:Prone Position / Q000502:physiology; D011446:Prospective Studies; D012137:Respiratory System / Q000503:physiopathology*; D018570:Risk Assessment; D012307:Risk Factors