title: Blood pressure and heart rate during ovariohysterectomy in pyometra and control dogs: a preliminary investigation.
abstract: BACKGROUND
  Surgery causes a stress response, a physiologic response to trauma. The intraoperative surgical stress response in dogs diagnosed with pyometra has not previously been described. The aim of this study was to investigate the intraoperative surgical stress response, assessed by blood pressure and heart rate measurements, in dogs diagnosed with pyometra and healthy controls. All dogs were premedicated with acepromazine and methadone, anaesthesia was induced with propofol and maintained with isoflurane, where after the dogs were subjected to ovariohysterectomy.
  
  
  RESULTS
  Eight dogs diagnosed with pyometra and eight healthy controls were used. Systolic blood pressure and heart rate were measured to assess the surgical stress response. Additionally propofol dosage at induction of anaesthesia and the end-tidal isoflurane concentration were investigated. The surgery was split into four phases. Phase 0 was the period 10 min before the skin incision, phase 1 was skin incision and opening of abdomen, phase 2 was manipulation of uterine horns, lifting of the ovary with stretching of the mesovarium, ligation and transection of mesovarium and phase 3 was ligation and transection of cervix, removal of organs and closing of the abdomen. Dosage of propofol at induction of anaesthesia was 3.6 ± 1 mg/kg in dogs with pyometra and 4.1 ± 1 in healthy controls (P = 0.37). In both groups, systolic blood pressure increased between phase 1 and 2, from 87 ± 15 to 114 ± 19 mmHg in dogs with pyometra, and from 88 ± 18 to 106 ± 20 mmHg in healthy controls, (both P < 0.0001). Systolic blood pressure did not differ significantly between groups in any of the phases. Heart rate and end-tidal concentration of isoflurane did not differ significantly between phases or between groups.
  
  
  CONCLUSIONS
  The increased blood pressure at removal of ovaries during ovariohysterectomy suggests a pronounced noxious stimulus at this part of the procedure. In principle, the study parameters and response to surgery did not differ significantly between dogs with pyometra and healthy controls.
authors.affiliation: Department of Clinical Sciences, Box 7054, 750 07, Uppsala, Sweden. Odd.Hoglund@slu.se.
authors.forename: Odd Viking
authors.identifier: http://orcid.org/0000-0003-0978-836X
authors.initials: OV
authors.lastname: Höglund
authors.affiliation: Alingsås Veterinärstuga AB, Björkekärrsvägen 26, 441 91, Alingsås, Sweden.
authors.forename: Johanna
authors.initials: J
authors.lastname: Lövebrant
authors.affiliation: Unit of Applied Statistics and Mathematics, Swedish University of Agricultural Sciences, Box 7032, 750 07, Uppsala, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Olsson
authors.affiliation: Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Box 7011, 750 07, Uppsala, Sweden.
authors.forename: Katja
authors.initials: K
authors.lastname: Höglund
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D005260:Female; D006339:Heart Rate; D007044:Hysterectomy / Q000662:veterinary*; D010052:Ovariectomy / Q000662:veterinary*; D055112:Pyometra / Q000601:surgery / Q000662:veterinary*; D013312:Stress, Physiological / Q000502:physiology*
keywords: Acepromazine; Blood pressure; Canine; Heart rate; Isoflurane; Methadone; Pyometra; Surgical stress