title: Postoperative changes in the full-field electroretinogram following sevoflurane anaesthesia.
abstract: OBJECTIVE
  We tested the hypothesis that disturbances of the visual pathway persist following general anaesthesia, even after normal clinical discharge criteria have been met.
  
  
  METHODS
  We performed full-field flash electroretinography in the right eye of 10 unpremedicated ASA I patients who underwent N2O/sevoflurane anaesthesia. Electroretinograms were recorded preoperatively, immediately after discharge from the recovery room and 2 h after discontinuation of sevoflurane. The time at which postanaesthesia discharge score first exceeded 9 was also noted. Data were analysed using paired, one-tailed Student's t-test.
  
  
  RESULTS
  Latency of the b-wave on the photopic electroretinogram was greater at each postoperative time point (30.5 +/- 0.9 and 30 +/- 1.3 ms), compared to preoperative values (29.2 +/- 0.8 ms, P < 0.001 and P = 0.04, respectively). The A-B amplitude of the b-wave was less postoperatively (220.3 +/- 52.7 and 210.3 +/- 42.7 pV) compared to values before operation (248.1 +/- 57.6 microV, P = 0.03 and P = 0.01, respectively). Oscillatory potential latencies were greater at each postoperative time point (21.4 +/- 0.5 and 20.8 +/- 0.6 ms) compared to before operation (20.4 +/- 0.4 ms, P < 0.001 and P = 0.03, respectively). Oscillatory potential amplitudes were less at the first postoperative time point (17.5 +/- 6.1 microV), compared to preoperative values (22 +/- 6.4 microV, P = 0.04).
  
  
  CONCLUSIONS
  Postoperative electroretinogram abnormalities are consistently present in patients who have undergone N2O/sevoflurane anaesthesia. These abnormalities persist beyond the time at which standard clinical discharge criteria have been met.
authors.affiliation: Cork University Hospital and University College Cork, Department of Anaesthesia and Intensive Care Medicine, Cork, Ireland. iohom@hotmail.com
authors.forename: G
authors.initials: G
authors.lastname: Iohom
authors.forename: A
authors.initials: A
authors.lastname: Whyte
authors.forename: T
authors.initials: T
authors.lastname: Flynn
authors.forename: G
authors.initials: G
authors.lastname: O'Connor
authors.forename: G
authors.initials: G
authors.lastname: Shorten
mesh_terms: D000328:Adult; D000762:Anesthesia Recovery Period; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D016009:Chi-Square Distribution; D004596:Electroretinography / Q000187:drug effects*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008738:Methyl Ethers / Q000008:administration & dosage*; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage; D011184:Postoperative Period; D011930:Reaction Time / Q000187:drug effects; D020127:Recovery of Function; D000077149:Sevoflurane; D013997:Time Factors; D014795:Visual Pathways / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide