title: Zero drift of intraventricular and subdural intracranial pressure monitoring systems.
abstract: OBJECTIVE
  To assess zero drift of intraventricular and subdural intracranial pressure (ICP) monitoring systems.
  
  
  METHODS
  A prospective study was conducted in patients who received Codman ICP monitoring in the neurosurgical department from January 2010 to December 2011. According to the location of sensors, the patients were categorized into two groups: intraventricular group and subdural group. Zero drift between the two groups and its association with the duration of ICP monitor were analyzed.
  
  
  RESULTS
  Totally, 22 patients undergoing intraventricular ICP monitoring and 27 receiving subdural ICP monitoring were enrolled. There was no significant difference in duration of ICP monitoring, zero drift value and its absolute value between intraventricular and subdural groups (5.38 d+/-2.58 d vs 4.58 d+/-2.24 d, 0.77 mm Hg+/-2.18 mm Hg vs 1.03 mm Hg+/-2.06 mm Hg, 1.68 mm Hg+/-1.55 mm Hg vs 1.70 mm Hg+/-1.53 mm Hg, respectively; all P larger than 0.05). Absolute value of zero drift in both groups significantly rose with the increased duration of ICP monitoring (P less than 0.05) while zero drift value did not. Moreover, daily absolute value in the intraventricular group was significantly smaller than that in the subdural group (0.27 mm Hg+/-0.32 mm Hg vs 0.29 mm Hg+/-0.18 mm Hg, P less than 0.05).
  
  
  CONCLUSIONS
  This study demonstrates that absolute value of zero drift significantly correlates with duration of both intraventricular and subdural ICP monitoring. Due to the smaller daily absolute value, ICP values recorded from intraventricular system may be more reliable than those from subdural system.
authors.affiliation: Neurosurgical Department, Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310003, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Hang-gen
authors.initials: HG
authors.lastname: Du
authors.forename: Li-chun
authors.initials: LC
authors.lastname: Yin
authors.forename: Min
authors.initials: M
authors.lastname: He
authors.forename: Guo-jun
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Tian
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Bi-lie
authors.initials: BL
authors.lastname: Hao
authors.forename: Hong-yu
authors.initials: HY
authors.lastname: Li
mesh_terms: D000368:Aged; D002552:Cerebral Ventricles; D005260:Female; D006801:Humans; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011446:Prospective Studies; D013355:Subdural Space