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To compare the effects of constant rate infusions (CRI) of fentanyl or dexmedetomidine, combined with lidocaine and ketamine, on cardiovascular response during surgery, sevoflurane requirement and postoperative pain in dogs undergoing mastectomy. Prospective, randomized, blinded, clinical trial. A total of 29 female dogs with mammary tumors. Premedication consisted of intramuscular acepromazine and morphine. General anesthesia was induced with intravenous propofol and maintained with sevoflurane. Dogs were randomized to be administered intravenous DLK [dexmedetomidine 1 μg kg–1 loading dose (LD) and 1 μg kg–1 hour–1; lidocaine 2 mg kg–1 LD and 3 mg kg–1 hour–1; ketamine 1 mg kg–1 LD and 0.6 mg kg–1 hour–1; n = 14] or FLK (fentanyl 5 μg kg–1 LD and 9 μg kg–1 hour–1; same doses of lidocaine and ketamine; n = 15) during anesthesia. Cardiorespiratory variables and end-tidal sevoflurane (F e′ Sevo) were recorded during surgery. The number of dogs administered ephedrine to treat arterial hypotension [mean arterial pressure (MAP) < 60 mmHg] was recorded. Meloxicam was administered to both groups. Postoperative pain and rescue analgesia requirement were assessed for 24 hours using the short form of the Glasgow Composite Measure Pain Scale. Data were compared using a mixed effects model or a Mann–Whitney test. More dogs required ephedrine in FLK than in DLK (67% versus 7%). Heart rate was not significantly different between groups, whereas lower values of MAP (p ≤ 0.01) and F e′ Sevo (p = 0.018) were observed in FLK than in DLK. Rescue analgesia was administered to 2/15 dogs in FLK and 0/14 dogs in DLK. Based on the cardiovascular response during surgery, intraoperative infusions of FLK and DLK provided adequate antinociception. Infusion of DLK provided greater stability of blood pressure. Both protocols resulted in minimal need for additional analgesia within 24 hours postoperatively. [ABSTRACT FROM AUTHOR]

To compare the propofol infusion rate and cardiopulmonary effects during total intravenous anesthesia with propofol alone and propofol combined with methadone, fentanyl or nalbuphine in domestic chickens undergoing ulna osteotomy. Prospective, randomized, experiment trial. A total of 59 healthy Hissex Brown chickens weighing 1.5 ± 0.2 kg. Anesthesia was induced with propofol (9 mg kg–1) administered intravenously (IV) and maintained with propofol (1.2 mg kg–1 minute–1) for 30 minutes. Birds were intubated and supplemented with 100% oxygen through a nonrebreathing circuit under spontaneous ventilation. Thereafter, each animal was randomly assigned to one of four groups: group P, no treatment; group PM, methadone (6 mg kg–1) intramuscularly (IM); group PN, nalbuphine IM (12.5 mg kg–1); and group PF, fentanyl IV (30 μg kg–1 loading dose, 30 μg kg–1 hour–1 constant rate infusion). During the osteotomy surgery, the propofol infusion rate was adjusted to avoid movement of birds and provide adequate anesthesia. Pulse rate, invasive blood pressure, respiratory frequency, end-tidal carbon dioxide partial pressure (P e′ CO 2) and hemoglobin oxygen saturation (SpO 2) were recorded. Data were available from 58 chickens. The mean ± standard deviation propofol infusion rate (mg kg–1 minute–1) for the duration of anesthesia was: group P, 0.81 ± 0.15; group PM, 0.66 ± 0.11; group PN, 0.60 ± 0.14; and group PF, 0.80 ± 0.07. Significant differences were P versus PM (p = 0.042), P versus PN (p = 0.002) and PF versus PN (p = 0.004). Pulse rate, blood pressure and SpO 2 remained acceptable for anesthetized birds with minor differences among groups. Values of P e′ CO 2 >60 mmHg (8 kPa) were observed in all groups. Methadone and nalbuphine, but not fentanyl, decreased the propofol infusion rate required for anesthesia maintenance, but resulted in no obvious benefit in physiological variables. [ABSTRACT FROM AUTHOR]