title: A comparison of cardiorespiratory variables during isoflurane-fentanyl and propofol-fentanyl anaesthesia for surgery in injured cats.
abstract: OBJECTIVE
  To compare haemodynamic and respiratory variables during isoflurane-fentanyl (IF) and propofol-fentanyl (PF) anaesthesia for surgery in injured cats.
  
  
  METHODS
  Prospective, randomized, controlled clinical study.
  
  
  METHODS
  Thirty-three client-owned injured cats undergoing orthopaedic surgery.
  
  
  METHODS
  Pre-anaesthetic medication was intravenous midazolam 1 mg kg(-1), butorphanol 0.4 mg kg(-1) and ketamine 2 mg kg(-1). Anaesthesia was induced with propofol (P) and maintained with either: (a) a continuous rate infusion (CRI) of fentanyl (F) 0.02 mg kg(-1) hour(-1) and isoflurane (initial end-tidal concentration of 1%), (b) a fentanyl CRI (dose as before) and sevoflurane (initial end-tidal concentration of 2%) or (c) a CRI of propofol (12 mg kg(-1) hour(-1)). All three techniques were given to effect until surgical anaesthesia was achieved. Heart rate and rhythm (ECG), mean arterial blood pressure, respiratory rate, tidal volume and end-tidal CO(2) concentration were recorded. Venous blood gas analysis was performed before and after sedation, and at the end of anaesthesia. Blood chemistry and blood cell counts were assessed before, at the end of, and 24 hours after anaesthesia. The variables recorded from cats anaesthetized with IF and PF were compared.
  
  
  RESULTS
  Mean end-expiratory isoflurane concentration was 1.19 +/- 0.19%. The propofol infusion rate was 11.4 +/- 0.8 mg kg(-1) hour(-1). No significant differences between the two groups in heart rate were identified; no cardiac dysrhythmias were recorded. Mean arterial blood pressure was significantly lower in IF cats during skin incision (p = 0.01), during surgery without intense surgical stimulation (p < 0.01) and during surgery with intense surgical stimulation (p = 0.01). Nine of 11 cats in the IF group were markedly hypotensive (34-49 mmHg) while seven of 11 cats in group PF were mildly hypotensive (49-59 mmHg). One of 11 cats in group IF and nine of 11 cats in group PF required intermittent positive pressure ventilation (IPPV) to maintain end-tidal CO(2) levels below 6.66 kPa (50 mmHg).
  
  
  CONCLUSIONS
  Despite the necessity to ventilate the lungs of cats in the PF group, arterial blood pressure was better maintained. Propofol-fentanyl anaesthesia is better for surgery in injured cats providing the means to impose IPPV are available.
authors.affiliation: Clinical Department for Small Animals and Horses, Clinic for Surgery, Ophthalmology and Dentistry, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria. lea.liehmann@vu-wien.ac.at
authors.forename: Lea
authors.initials: L
authors.lastname: Liehmann
authors.forename: Martina
authors.initials: M
authors.lastname: Mosing
authors.forename: Ulrike
authors.initials: U
authors.lastname: Auer
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D019162:Anesthetics, Combined / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D001784:Blood Gas Analysis / Q000662:veterinary; D002415:Cats / Q000097:blood / Q000293:injuries / Q000502:physiology* / Q000601:surgery; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006439:Hemodynamics / Q000187:drug effects*; D007530:Isoflurane / Q000008:administration & dosage; D008297:Male; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D016896:Treatment Outcome; D014947:Wounds and Injuries / Q000601:surgery / Q000662:veterinary
chemical_list: D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D007530:Isoflurane; D005283:Fentanyl; D015742:Propofol