title: Pressure inside the neuroendoscope: correlation with epidural intracranial pressure during neuroendoscopic procedures.
abstract: BACKGROUND
  During neuroendoscopic procedures, pressure inside the neuroendoscope (PIN) monitored through the irrigation channel correlates with the occurrence of postoperative complications. Our aim was to analyze the reliability of PIN measurement as a surrogate for intracranial pressure (ICP) by comparing PIN with simultaneously epidural ICP measurement as the standard.
  
  
  METHODS
  Seventeen consecutive patients undergoing neuroendoscopy were studied prospectively. Type and length of procedure and PIN and epidural ICP values during neuroendoscopy were recorded. Lin's concordance coefficient and Bland-Altman analysis of agreement were used to assess correspondence between the 2 systems.
  
  
  RESULTS
  A consistent relation between PIN and epidural ICP waveforms was observed during neuroendoscopic navigation. A strong Pearson correlation between PIN and epidural ICP data were found in 15 patients. Epidural ICP values were systematically higher than PIN values in 15 patients. Lin concordance coefficients showed moderate global agreement between the 2 methods, at 0.58 (95% confidence interval, 0.577-0.592). In 6 cases (35.2%) concordance was good according to this analysis, in 7 cases (41.2%) agreement was moderate/fair, and in 4 cases (23.5%) agreement was poor. The Bland-Altman analysis of patient data showed good agreement between the PIN and epidural ICP measurements for most patients, although discrepancies were greater at higher ICP values for 11 patients. Bland-Altman analysis of the complete dataset, after the normalization of individual's measurements, showed good overall agreement.
  
  
  CONCLUSIONS
  PIN measurement seems useful for evaluating ICP changes related to neuroendoscopic procedures and seems to be more consistent than epidural ICP at high pressures.
authors.affiliation: Department of Anesthesiology, Hospital Clínic de Barcelona, Barcelona, Spain.
authors.forename: Lydia
authors.initials: L
authors.lastname: Salvador
authors.forename: Ricard
authors.initials: R
authors.lastname: Valero
authors.forename: Jesús
authors.initials: J
authors.lastname: Carazo
authors.forename: Luis
authors.initials: L
authors.lastname: Caral
authors.forename: José
authors.initials: J
authors.lastname: Rios
authors.forename: Enrique
authors.initials: E
authors.lastname: Carrero
authors.forename: Javier
authors.initials: J
authors.lastname: Tercero
authors.forename: Nicolas
authors.initials: N
authors.lastname: de Riva
authors.forename: Paola
authors.initials: P
authors.lastname: Hurtado
authors.forename: Enrique
authors.initials: E
authors.lastname: Ferrer
authors.forename: Neus
authors.initials: N
authors.lastname: Fábregas
mesh_terms: D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D004724:Endoscopy; D004824:Epidural Space / Q000502:physiology*; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D044582:Neuroendoscopes; D044583:Neuroendoscopy; D019635:Neurosurgical Procedures; D011446:Prospective Studies; D055815:Young Adult