title: Effects of pneumoperitoneum and Trendelenburg position on intracranial pressure assessed using different non-invasive methods.
abstract: BACKGROUND
  The laparoscopic approach is becoming increasingly frequent for many different surgical procedures. However, the combination of pneumoperitoneum and Trendelenburg positioning associated with this approach may increase the patient's risk for elevated intracranial pressure (ICP). Given that the gold standard for the measurement of ICP is invasive, little is known about the effect of these common procedures on ICP.
  
  
  METHODS
  We prospectively studied 40 patients without any history of cerebral disease who were undergoing laparoscopic procedures. Three different methods were used for non-invasive estimation of ICP: ultrasonography of the optic nerve sheath diameter (ONSD); transcranial Doppler-based (TCD) pulsatility index (ICPPI); and a method based on the diastolic component of the TCD cerebral blood flow velocity (ICPFVd). The ONSD and TCD were measured immediately after induction of general anaesthesia, after pneumoperitoneum insufflation, after Trendelenburg positioning, and again at the end of the procedure.
  
  
  RESULTS
  The ONSD, ICPFVd, and ICPPIincreased significantly after the combination of pneumoperitoneum insufflation and Trendelenburg positioning. The ICPFVdshowed an area under the curve of 0.80 [95% confidence interval (CI) 0.70-0.90] to distinguish the stage associated with the application of pneumoperitoneum and Trendelenburg position; ONSD and ICPPIshowed an area under the curve of 0.75 (95% CI 0.65-0.86) and 0.70 (95% CI 0.58-0.81), respectively.
  
  
  CONCLUSIONS
  The concomitance of pneumoperitoneum and the Trendelenburg position can increase ICP as estimated with non-invasive methods. In high-risk patients undergoing laparoscopic procedures, non-invasive ICP monitoring through a combination of ONSD ultrasonography and TCD-derived ICPFVdcould be a valid option to assess the risk of increased ICP.
authors.affiliation: Neurosciences Critical Care Unit, Box 1, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK kiarobba@gmail.com.|Department of Anaesthesiology, Mura delle Cappuccine 16, 16100 Galliera Hospital, Genoa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Robba
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: D
authors.initials: D
authors.lastname: Cardim
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: J
authors.initials: J
authors.lastname: Donnelly
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, St George's Hospital, University of London, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Bertuccio
authors.affiliation: Department of Neurosurgery, Galliera Hospital, Mura delle Cappuccine 16, 16100 University of Genoa, Genoa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Bacigaluppi
authors.affiliation: School of Public Health, Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa 16132, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Bragazzi
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: B
authors.initials: B
authors.lastname: Cabella
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Neurosciences Critical Care Unit, Box 1, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: B
authors.initials: B
authors.lastname: Matta
authors.affiliation: Department of Anaesthesiology, Mura delle Cappuccine 16, 16100 Galliera Hospital, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Lattuada
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Czosnyka
mesh_terms: D000328:Adult; D000368:Aged; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D018475:Head-Down Tilt / Q000502:physiology*; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000000981:diagnostic imaging / Q000503:physiopathology; D011027:Pneumoperitoneum / Q000503:physiopathology*; D011446:Prospective Studies; D014463:Ultrasonography / Q000379:methods*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods
keywords: head-down tilt; intracranial pressure; optic nerve sheath diameter; pneumoperitoneum; transcranial Doppler