Optic nerve sheath diameter remains constant during robot assisted laparoscopic radical prostatectomy

PLoS One. 2014 Nov 4;9(11):e111916. doi: 10.1371/journal.pone.0111916. eCollection 2014.

Abstract

Background: During robot assisted laparoscopic radical prostatectomy (RALRP), a CO2 pneumoperitoneum (CO2PP) is applied and the patient is placed in a head-down position. Intracranial pressure (ICP) is expected to acutely increase under these conditions. A non-invasive method, the optic nerve sheath diameter (ONSD) measurement, may warn us that the mechanism of protective cerebrospinal fluid (CSF) shifts becomes exhausted.

Methods: After obtaining IRB approval and written informed consent, ONSD was measured by ocular ultrasound in 20 ASA I-II patients at various stages of the RALRP procedure: baseline awake, after induction, after applying the CO2PP, during head-down position, after resuming the supine position, in the postoperative anaesthesia care unit, and on day one postoperatively. Cerebral perfusion pressure (CPP) was calculated as the mean arterial (MAP) minus central venous pressure (CVP).

Results: The ONSD did not change during head-down position, although the CVP increased from 4.2(2.5) mm Hg to 27.6(3.8) mm Hg. The CPP was decreased 70 min after assuming the head-down position until 15 min after resuming the supine position, but remained above 60 mm Hg at all times.

Conclusion: Even though ICP has been documented to increase during CO2PP and head-down positioning, we did not find any changes in ONSD during head-down position. These results indicate that intracranial blood volume does not increase up to a point that CSF migration as a compensation mechanism becomes exhausted, suggesting any increases in ICP are likely to be small.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Head-Down Tilt
  • Humans
  • Intracranial Hypertension / diagnosis*
  • Intracranial Hypertension / prevention & control
  • Intraoperative Complications / diagnosis*
  • Intraoperative Complications / prevention & control
  • Laparoscopy
  • Male
  • Middle Aged
  • Optic Nerve / pathology*
  • Organ Size
  • Prostatectomy
  • Robotic Surgical Procedures*

Grants and funding

The authors received no specific funding for this work. This study was solely supported by departmental and institutional funding: Department of Anaesthesiology and Intensive care medicine, OLV Clinic, Aalst, Belgium. Moorselbaan 164, 9300 Aalst, Belgium. No individuals other than the named authors played any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No current funding sources for this study were used other than institutional fundings.