title: The effect of the stage of the ovarian cycle (anoestrus or dioestrus) and of pregnancy on the incidence of gastro-oesophageal reflux in dogs undergoing ovariohysterectomy.
abstract: OBJECTIVE
  To investigate the potential association of increased blood progesterone (P4 ) concentrations and/or late pregnancy with the incidence of gastro-oesophageal reflux (GOR), in healthy bitches undergoing ovariohysterectomy under general anaesthesia during anoestrus or dioestrus or during the second half of pregnancy.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Ninety-four healthy, female, dogs, aged 1-8 years presented for elective ovariohysterectomy.
  
  
  METHODS
  Non-pregnant animals were classified into group A (anoestrus) (n = 35) if blood P4 concentration was sufficiently low or group D (dioestrus) (n = 26) if blood P4 concentration was sufficiently high. All animals in the second half of pregnancy were classified into group P (n = 33). Acepromazine (0.05 mg kg(-1) ) was administered intramuscularly as preanaesthetic medication, and sodium thiopental (10 mg kg(-1) , with additional doses if needed) was administered intravenously (IV) for induction of anaesthesia. After endotracheal intubation, halothane (1.1-1.3% end-tidal concentration) in oxygen was used for maintenance of anaesthesia. Lower oesophageal pH was monitored continuously throughout surgery using a pH-measuring probe. Reflux was considered to have occurred whenever pH values of >7.5 (alkaline reflux) or <4 (acid reflux) were recorded. On completion of surgery, carprofen (4 mg kg(-1) ) was administered IV. Further administration of analgesics post-operatively was dictated by visual analogue scale pain scoring.
  
  
  RESULTS
  Acid GOR was observed in five of 26 dogs in group D, six of 35 group A, and 12 of 33 group P (p = 0.152). The incidence of GOR in group P approached statistical significance and was higher than the incidence in the combined group A + D (one sided p = 0.044, two sided p = 0.077).
  
  
  CONCLUSIONS
  In dogs undergoing ovariohysterectomy, GOR during anaesthesia occurs with a high incidence in dogs in the second half of pregnancy compared to non-pregnant animals during anoestrus or dioestrus.
  
  
  CONCLUSIONS
  Measures could be taken in such cases to avoid the consequences of potential reflux.
authors.affiliation: Anaesthesia and Intensive Care Unit, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Tilemahos L
authors.initials: TL
authors.lastname: Anagnostou
authors.affiliation: Anaesthesia and Intensive Care Unit, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Ioannis
authors.identifier: http://orcid.org/0000-0001-5575-7244
authors.initials: I
authors.lastname: Savvas
authors.affiliation: Anaesthesia and Intensive Care Unit, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: George M
authors.initials: GM
authors.lastname: Kazakos
authors.affiliation: Surgery and Obstetrics Unit, Department of Clinical Sciences, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Haralabos N
authors.initials: HN
authors.lastname: Ververidis
authors.affiliation: Laboratory of Pathology, Department of Infectious and Parasitic Diseases and Pathology, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Psalla
authors.affiliation: Anaesthesia and Intensive Care Unit, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Charalampos
authors.initials: C
authors.lastname: Kostakis
authors.affiliation: Alexandrion Technological Institute of Thessaloniki, Thessaloniki, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Skepastianos
authors.affiliation: Anaesthesia and Intensive Care Unit, School of Veterinary Medicine, Faculty of Health, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Raptopoulos
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000209:etiology*; D004285:Dogs; D030762:Estrous Cycle / Q000097:blood / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000209:etiology / Q000662:veterinary*; D007044:Hysterectomy / Q000009:adverse effects / Q000662:veterinary; D015994:Incidence; D010052:Ovariectomy / Q000009:adverse effects / Q000662:veterinary; D011183:Postoperative Complications / Q000209:etiology / Q000662:veterinary*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies
chemical_list: D011374:Progesterone
keywords: anaesthesia; aspiration; dog; gastro-oesophageal reflux; oesophageal stricture; pregnancy