title: Intraocular pressure variation during colorectal laparoscopic surgery: standard pneumoperitoneum leads to reversible elevation in intraocular pressure.
abstract: BACKGROUND
  The potential effects of laparoscopic surgery on intra- and postoperative intraocular pressure (IOP) are not completely understood. Although prior studies have reported that pneumoperitoneum may increase IOP, it is not clear whether this increase is related to the effects of pneumoperitoneum or to the patient's position, such as the Trendelenburg position. This study aimed to evaluate the potential fluctuations of IOP during colorectal laparoscopic surgery in two groups of patients: those with and those without Trendelenburg positioning.
  
  
  METHODS
  For this prospective study 45- to 85-year-old patients undergoing laparoscopic colorectal surgery were enrolled after a thorough ophthalmologic assessment. The study protocol included measurement of IOP at eight different time points (before, during, and after surgery) using a contact tonometer in both eyes.
  
  
  RESULTS
  The study enrolled 29 patients: 17 (58.6%) with Trendelenburg position placement during surgery and 12 (41.4%) without Trendelenburg positioning. The two groups did not differ in terms of gender, age, body mass index (BMI), American Society of Anesthesiology (ASA) class, or operative time. In all the patients, pneumoperitoneum induction led to a mild rise in IOP, averaging 4.1 mmHg. The patients with Trendelenburg positioning showed a greater increase than the patients without it (5.05 vs 4.23 mmHg at 45 min; p = 0.179), but IOP evaluation 48 h after surgery showed no substantial differences between the two groups. Among the 29 patients, 17 (58.6%) showed an increase in IOP of 5 mmHg or more during surgery. A greater percentage of the patients who underwent Trendelenburg positioning showed an IOP increase of 5 mmHg or more (76.5 vs 33.3%; p = 0.020). At the multivariate analysis, no potential predictors of increased IOP during surgery was identified.
  
  
  CONCLUSIONS
  Standard pneumoperitoneum (≤14 mmHg) led to mild and reversible IOP increases. A trend was observed toward a greater IOP increase in patients with Trendelenburg positioning. Thus, the patient's position during surgery may represent a stronger risk factor for IOP increase than pneumoperitoneum-related intraabdominal pressure.
authors.affiliation: Centre for Macular Research, San Mauro Torinese and Torino Eye Hospital, Via Roma 73, Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Grosso
authors.forename: Gitana
authors.initials: G
authors.lastname: Scozzari
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Bert
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Mabilia
authors.forename: Roberta
authors.initials: R
authors.lastname: Siliquini
authors.forename: Mario
authors.initials: M
authors.lastname: Morino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011028:Pneumoperitoneum, Artificial; D011446:Prospective Studies
references.citation: Med Oncol. 2011 Dec;28(4):925-33
references.pmid: 20458560
references.citation: J Glaucoma. 2009 Apr-May;18(4):272-9
references.pmid: 19365190
references.citation: Invest Ophthalmol Vis Sci. 2011 Feb 09;52(2):737-43
references.pmid: 20861474
references.citation: Surv Ophthalmol. 2009 Nov-Dec;54(6):643-62
references.pmid: 19665744
references.citation: Tech Coloproctol. 2012 Oct;16(5):331-5
references.pmid: 22936587
references.citation: Eur J Ophthalmol. 2011 May-Jun;21(3):251-7
references.pmid: 20853257
references.citation: Anesth Analg. 2009 Aug;109(2):473-8
references.pmid: 19608821
references.citation: Anesth Analg. 2009 Nov;109(5):1534-45
references.pmid: 19713263
references.citation: Surg Endosc. 2008 May;22(5):1146-60
references.pmid: 18071810
references.citation: Arch Ophthalmol. 2007 Aug;125(8):1044-50
references.pmid: 17698750
references.citation: J Glaucoma. 2006 Jun;15(3):213-7
references.pmid: 16778643
references.citation: Anesth Analg. 2003 Aug;97(2):471-474
references.pmid: 12873937
references.citation: Ophthalmology. 2008 Jun;115(6):934-40
references.pmid: 17936908
references.citation: Clin Exp Ophthalmol. 2011 Apr;39(3):252-8
references.pmid: 20973906
references.citation: Eye (Lond). 2008 Apr;22(4):503-6
references.pmid: 17159973
references.citation: Anesth Analg. 1998 Jun;86(6):1283-8
references.pmid: 9620521
references.citation: Ophthalmology. 2005 Oct;112(10):1670-5
references.pmid: 16095707
references.citation: Ann Surg. 2003 Mar;237(3):335-42
references.pmid: 12616116