title: Effect of duration and type of anesthetic on tear production in dogs.
abstract: OBJECTIVE
  To determine effects of duration and type of anesthetic on tear production in dogs.
  
  
  METHODS
  8 female Beagles.
  
  
  METHODS
  Each dog was randomly allocated into 1 of 4 groups according to a Latin square design to receive anesthesia as follows: 1 hour with isoflurane, 1 hour with desflurane, 4 hours with isoflurane, and 4 hours with desflurane. Each dog was anesthetized with the selected inhalant 4 times during a 4-week period, with at least 5 days separating anesthetic episodes. Aqueous tear production was measured via the Schirmer I tear test at baseline and 10 minutes, 30 minutes, and 1 hour after induction of anesthesia as well as 2, 3, and 4 hours after induction for the 4-hour groups. Tear production was also measured after the dogs were standing after recovery from anesthesia and 2, 10, and 22 hours after recovery from anesthesia.
  
  
  RESULTS
  Aqueous tear production was significantly reduced in dogs during anesthesia and returned to baseline values immediately after recovery and until 10 hours after anesthesia in all treatment groups. Inhalant type and duration had no significant effect. Neither lateral recumbency nor left versus right eyes had a significant effect.
  
  
  CONCLUSIONS
  Results suggested that inhalant anesthetics did not reduce tear production after anesthesia and that longer-duration anesthesia did not cause decreased tear production, compared with shorter-duration anesthesia.
authors.affiliation: Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA. mkshep@uga.edu
authors.forename: Molly K
authors.initials: MK
authors.lastname: Shepard
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Accola
authors.forename: Luis A
authors.initials: LA
authors.lastname: Lopez
authors.forename: Michael R
authors.initials: MR
authors.lastname: Shaughnessy
authors.forename: Erik H
authors.initials: EH
authors.lastname: Hofmeister
mesh_terms: D000769:Anesthesia, Inhalation / Q000009:adverse effects / Q000662:veterinary*; D000777:Anesthetics / Q000009:adverse effects*; D000818:Animals; D000077335:Desflurane; D004285:Dogs; D005260:Female; D007530:Isoflurane / Q000009:adverse effects* / Q000031:analogs & derivatives*; D010375:Pedigree; D011897:Random Allocation; D013666:Tears / Q000378:metabolism*
chemical_list: D000777:Anesthetics; D000077335:Desflurane; D007530:Isoflurane