title: Sonographic optic nerve sheath diameter as a surrogate measure for intracranial pressure in anesthetized patients in the Trendelenburg position.
abstract: BACKGROUND
  It remains to be elucidated whether the Trendelenburg position increases intracranial pressure (ICP). ICP can be evaluated by measuring the sonographic optic nerve sheath diameter (ONSD). We investigated the effect of the isolated Trendelenburg position on ONSD in patients undergoing robot-assisted laparoscopic radical prostatectomy. Additionally, we evaluated the effect of the Trendelenburg position combined with pneumoperitoneum on ONSD.
  
  
  METHODS
  Twenty-one patients scheduled for robot-assisted laparoscopic radical prostatectomy were enrolled. Sonographic ONSDs and hemodynamic parameters were measured at specific time points: in the supine position after induction of anesthesia, 3 min after the steep Trendelenburg position (35° incline), 3 min after the steep Trendelenburg position combined with pneumoperitoneum, and in the supine position after desufflation of the pneumoperitoneum.
  
  
  RESULTS
  The ONSD 3 min after the steep Trendelenburg position was significantly higher than that of the supine position after induction of anesthesia (5.1 ± 0.3 mm vs. 4.5 ± 0.4 mm). In addition, the ONSD 3 min after the steep Trendelenburg position combined with pneumoperitoneum was higher than that of the supine position after induction of anesthesia (4.9 ± 0.4 mm vs. 4.5 ± 0.4 mm). The ONSD in the supine position after desufflation of the pneumoperitoneum was similar to that in the supine position after induction of anesthesia.
  
  
  CONCLUSIONS
  Use of the isolated steep Trendelenburg position, for even a short duration, increased the sonographic ONSD, providing a better understanding of the effect of only a transient steep Trendelenburg position on ONSD as a surrogate measure for ICP.
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Ji-Hyun
authors: JH
authors: Chin
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Hyungseok
authors: H
authors: Seo
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Eun-Ho
authors: EH
authors: Lee
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Joohyun
authors: J
authors: Lee
authors: Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors: Jun Hyuk
authors: JH
authors: Hong
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Jai-Hyun
authors: JH
authors: Hwang
authors: Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 Republic of Korea.
authors: Young-Kug
authors: YK
authors: Kim
mesh_terms: D000777:Anesthetics / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D018475:Head-Down Tilt / Q000502:physiology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology; D015588:Observer Variation; D009900:Optic Nerve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011028:Pneumoperitoneum, Artificial; D011468:Prostatectomy / Q000379:methods; D065287:Robotic Surgical Procedures / Q000379:methods; D016683:Supine Position / Q000502:physiology; D013874:Thiopental / Q000494:pharmacology; D014463:Ultrasonography; D014673:Vecuronium Bromide / Q000494:pharmacology
chemical_list: D000777:Anesthetics; D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide; D013874:Thiopental
keywords: Intracranial pressure; Optic nerve sheath diameter; Trendelenburg position