title: Invasive and ultrasound based monitoring of the intracranial pressure in an experimental model of epidural hematoma progressing towards brain tamponade on rabbits.
abstract: BACKGROUND
  An experimental epidural hematoma model was used to study the relation of ultrasound indices, namely, transcranial color-coded-Doppler (TCCD) derived pulsatility index (PI), optic nerve sheath diameter (ONSD), and pupil constriction velocity (V) which was derived from a consensual sonographic pupillary light reflex (PLR) test with invasive intracranial pressure (ICP) measurements.
  
  
  METHODS
  Twenty rabbits participated in the study. An intraparenchymal ICP catheter and a 5F Swan-Ganz catheter (SG) for the hematoma reproduction were used. We successively introduced 0.1 mL increments of autologous blood into the SG until the Cushing reaction occurred. Synchronous ICP and ultrasound measurements were performed accordingly.
  
  
  RESULTS
  A constant increase of PI and ONSD and a decrease of V values were observed with increased ICP values. The relationship between the ultrasound variables and ICP was exponential; thus curved prediction equations of ICP were used. PI, ONSD, and V were significantly correlated with ICP (r² = 0.84 ± 0.076, r² = 0.62 ± 0.119, and r² = 0.78 ± 0.09, resp. (all P < 0.001)).
  
  
  CONCLUSIONS
  Although statistically significant prediction models of ICP were derived from ultrasound indices, the exponential relationship between the parameters underpins that results should be interpreted with caution and in the current experimental context.
authors.affiliation: Department of Neurosurgery, Athens General Hospital "G. Gennimatas", 11527 Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kasapas
authors.affiliation: 2nd Department of Surgery, Athens Medical School, Laiko University Hospital, 11527 Athens, Greece.
authors.forename: Angela
authors.initials: A
authors.lastname: Diamantopoulou
authors.affiliation: Intensive Care Unit, Athens General Hospital "G. Gennimatas", Athens, Greece.
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Pentilas
authors.affiliation: Experimental Research Center ELPEN, 19009 Athens, Greece.
authors.forename: Apostolos
authors.initials: A
authors.lastname: Papalois
authors.affiliation: 3rd ICU Department, Athens Medical School, Evgenideio University Hospital, 15128 Athens, Greece.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Douzinas
authors.affiliation: 2nd Department of Surgery, Athens Medical School, Laiko University Hospital, 11527 Athens, Greece.
authors.forename: Gregorios
authors.initials: G
authors.lastname: Kouraklis
authors.affiliation: ICU, Amiens University Hospital, 80054 Amiens, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Slama
authors.affiliation: Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22903, USA ; Department of Anesthesiology, King Fahad Medical City, Riyadh 11525, Saudi Arabia.
authors.forename: Abdullah Sulieman
authors.initials: AS
authors.lastname: Terkawi
authors.affiliation: Department of Internal Medicine, School of Medicine, University of South Carolina, Columbia, SC 29225, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Blaivas
authors.affiliation: Wyle Science, Technology & Engineering Group/NASA Bioastronautics, Houston, TX 77058, USA.
authors.forename: Ashot Ernest
authors.initials: AE
authors.lastname: Sargsyan
authors.affiliation: Department of Internal Medicine, School of Medicine, University of South Carolina, Columbia, SC 29225, USA.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Karakitsos
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006407:Hematoma, Epidural, Cranial / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007427:Intracranial Pressure; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D011817:Rabbits; D014463:Ultrasonography