title: Continuous infusion of propofol in dogs premedicated with methotrimeprazine.
abstract: OBJECTIVE
  To evaluate the cardiopulmonary and clinical effects of three different infusion rates of propofol in dogs premedicated with methotrimeprazine.
  
  
  METHODS
  Randomized experimental trial.
  
  
  METHODS
  Ten healthy adult mixed-breed male and female dogs, weighing from 14 to 20 kg.
  
  
  METHODS
  Dogs were premedicated with methotrimeprazine [1 mg kg-1intravenously (IV)] followed by induction of anesthesia with 4.5 mg kg-1of propofol IV and maintenance with propofol for 60 minutes as follows: T1, 0.2 mg kg-1minute-1; T2, 0.3 mg kg-1minute-1; and T3, 0.4 mg kg-1minute-1. Heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), end-tidal CO2(PETCO2), arterial hemoglobin O2saturation, arterial blood gases, and pedal and cutaneous reflexes were measured before and 5, 10, 20, 30, 45 and 60 minutes after the beginning of the propofol infusion. Statistical analysis was performed using an anova.
  
  
  RESULTS
  Heart rate increased during anesthesia in all cases and arterial blood pressure decreased only in dogs in the T3 category. Respiratory depression was proportional to the infusion rate of propofol. Muscle relaxation was satisfactory, but analgesia was inadequate in the three treatments.
  
  
  CONCLUSIONS
  The infusion of 0.2-0.4 mg kg-1minute-1of propofol produced a dose-dependent respiratory depression. The presence of a pedal withdrawal reflex and marked cardiovascular responses to this noxious stimulus suggests that anesthesia may not be of sufficient depth for surgery to be carried out.
  
  
  CONCLUSIONS
  Although several studies have been performed using propofol in animals, few studies have investigated the cardiopulmonary and analgesic effects with different doses. The determination of an adequate propofol infusion rate is necessary for the routine use of this intravenous anesthetic for the maintenance of anesthesia during major surgical procedures in dogs.
authors.affiliation: Department of Clinical Sciences, School of Veterinary Medicine, São Paulo State University, UNESP Rua Clóvis Pestana, 793, Araçatuba, São Paulo 16050-680, Brazil.
authors.forename: Antonio Ja
authors.initials: AJ
authors.lastname: Aguiar
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, São Paulo State University - UNESP, Distrito Rubião Júnior, Botucatu, São Paulo 18618-000, Brazil.
authors.forename: Stelio Pl
authors.initials: SP
authors.lastname: Luna
authors.affiliation: Department of Clinical Sciences, School of Veterinary Medicine, São Paulo State University, UNESP Rua Clóvis Pestana, 793, Araçatuba, São Paulo 16050-680, Brazil.
authors.forename: Valéria Nls
authors.initials: VN
authors.lastname: Oliva
authors.affiliation: Department of Clinical Sciences, School of Veterinary Medicine, São Paulo State University, UNESP Rua Clóvis Pestana, 793, Araçatuba, São Paulo 16050-680, Brazil.
authors.forename: Flávia R
authors.initials: FR
authors.lastname: Eugênio
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, São Paulo State University - UNESP, Distrito Rubião Júnior, Botucatu, São Paulo 18618-000, Brazil.
authors.forename: Gladys B
authors.initials: GB
authors.lastname: Castro
keywords: anesthesia; dog; methotrimeprazine; propofol