title: Changes in intra-ocular pressure during general anaesthesia. A comparison of spontaneous breathing through a laryngeal mask with positive pressure ventilation through a tracheal tube.
abstract: Changes in-intra-ocular pressure during spontaneous ventilation with a laryngeal mask were compared with controlled ventilation using a tracheal tube in 40 patients undergoing intra-ocular surgery under general anaesthesia. Intra-ocular pressure was measured before induction, after establishing the airway, at the end of the operation and after removal of the airway device. Anaesthesia was induced with propofol and maintained with enflurane and nitrous oxide in oxygen. Mean end-tidal carbon dioxide tension was significantly higher during spontaneous ventilation than during controlled ventilation 5 min after establishing the airway (5.7 versus 4.5) and at the end of surgery (6.1 versus 4.2) (p < 0.001). Despite this, intra-ocular pressures were lower than baseline and similar in the two groups throughout anaesthesia. At the end of surgery, intra-ocular pressure (mmHg) was 11.2 and 8.6 during spontaneous or controlled ventilation respectively. One min after removal of the device, mean intra-ocular pressure (mmHg) in the tracheal tube group (16.0) was slightly higher than baseline (15.3) and was significantly higher than the laryngeal mask group (10.9) (p < 0.01). Spontaneous ventilation with a laryngeal mask is an acceptable alternative to controlled ventilation with tracheal intubation in elective intra-ocular surgery.
authors.affiliation: University Department of Surgical and Anaesthetic Sciences, Royal Hallamshire Hospital, Sheffield.
authors.forename: Y
authors.initials: Y
authors.lastname: Myint
authors.forename: A K
authors.initials: AK
authors.lastname: Singh
authors.forename: J E
authors.initials: JE
authors.lastname: Peacock
authors.forename: A
authors.initials: A
authors.lastname: Padfield
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000502:physiology; D002387:Cataract Extraction; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D007432:Intraoperative Period; D007442:Intubation, Intratracheal; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D012119:Respiration
chemical_list: D002245:Carbon Dioxide