The aim of the study was to evaluate sedation level and analgesic efficacy produced by the association of methadone 0.5 mg/kg and dexmedetomidine 5 mcg/kg for neutering surgery in cats. Thirty client‐owned cats (8 males and 22 females) anaesthetised for elective neutering surgery, considered healthy on the basis of clinical exam and haematological tests, were enrolled in the study. Cats were premedicated with dexmedetomidine 5 mcg/kg and methadone 0.5 mg/kg administered intramuscularly. Cats were then induced with propofol, intubated and maintained with isoflurane in 100% oxygen. Time to reach the sedative effects wasregistered as well as the following clinical parameters: heart rate (HR), systolic arterial pressure, using the doppler technique (SAP), respiration rate (RR), end tidal CO2 (EtCO2), haemoglobin oxygen saturation (SpO2), temperature (T°) and end tidal isoflurane percentage (EtIso). All the parameters were recorded every five minutes until the end of anaesthesia. Three different simple descriptive four points scales were used to evaluate the degree of sedation after premedication, the catheter placement and the quality of recovery after general anaesthesia (Bortolami et.al 2011), starting from 0 (no sedation, difficult catheter placement, poor recovery) to 3 (profound sedation, very easy catheter placement, excellent recovery). Mean time to reach the maximum sedation level was 4 ± 5 minutes; median sedation score resulted 2 (0‐3), median catheter placement score was 3 (0‐3) and median recovery quality score was 3 (0‐3). Mean dosage of propofol for intubation resulted 1.6 ± 1 mg/kg. EtIso during the surgery variated from 0.83 to 1.4 %. Nine of the 30 cats (30%) in the study required fentanyl rescue analgesia during the surgery; one cat received dopamine infusion as hypotension treatment; 6 cats received assisted mechanical ventilation and 1 cat received controlled mechanical ventilation. The association of dexmedetomidine 5 mcg/kg and methadone 0.5 mg/kg resulted in an overall good quality sedation with some exception: in fact 3 cats presented a poor sedation score (0‐1), nevertheless the score for the catheter placement was always 2 or more. The onset of the sedation was quite fast and the association of drugs resulted in propofol dose‐sparing effect. A high percentage of patients required rescue pain management during surgery showing inadequate analgesia in those cases. In conclusion premedication with methadone 0.5 mg/kg and dexmedetomidine 5 mcg/kg given intramuscularly, resulted in a good combination drug protocol which allow to handle cats easily and the use of low‐dose propofol for anaesthesia induction; however the analgesia obtained was not always adequate.
Methadone and Dexmedetomidine combination as premedicant for ovariectomy and orchiectomy in cat
BRIGANTI, ANGELA;BREGHI, GLORIA
2013-01-01
Abstract
The aim of the study was to evaluate sedation level and analgesic efficacy produced by the association of methadone 0.5 mg/kg and dexmedetomidine 5 mcg/kg for neutering surgery in cats. Thirty client‐owned cats (8 males and 22 females) anaesthetised for elective neutering surgery, considered healthy on the basis of clinical exam and haematological tests, were enrolled in the study. Cats were premedicated with dexmedetomidine 5 mcg/kg and methadone 0.5 mg/kg administered intramuscularly. Cats were then induced with propofol, intubated and maintained with isoflurane in 100% oxygen. Time to reach the sedative effects wasregistered as well as the following clinical parameters: heart rate (HR), systolic arterial pressure, using the doppler technique (SAP), respiration rate (RR), end tidal CO2 (EtCO2), haemoglobin oxygen saturation (SpO2), temperature (T°) and end tidal isoflurane percentage (EtIso). All the parameters were recorded every five minutes until the end of anaesthesia. Three different simple descriptive four points scales were used to evaluate the degree of sedation after premedication, the catheter placement and the quality of recovery after general anaesthesia (Bortolami et.al 2011), starting from 0 (no sedation, difficult catheter placement, poor recovery) to 3 (profound sedation, very easy catheter placement, excellent recovery). Mean time to reach the maximum sedation level was 4 ± 5 minutes; median sedation score resulted 2 (0‐3), median catheter placement score was 3 (0‐3) and median recovery quality score was 3 (0‐3). Mean dosage of propofol for intubation resulted 1.6 ± 1 mg/kg. EtIso during the surgery variated from 0.83 to 1.4 %. Nine of the 30 cats (30%) in the study required fentanyl rescue analgesia during the surgery; one cat received dopamine infusion as hypotension treatment; 6 cats received assisted mechanical ventilation and 1 cat received controlled mechanical ventilation. The association of dexmedetomidine 5 mcg/kg and methadone 0.5 mg/kg resulted in an overall good quality sedation with some exception: in fact 3 cats presented a poor sedation score (0‐1), nevertheless the score for the catheter placement was always 2 or more. The onset of the sedation was quite fast and the association of drugs resulted in propofol dose‐sparing effect. A high percentage of patients required rescue pain management during surgery showing inadequate analgesia in those cases. In conclusion premedication with methadone 0.5 mg/kg and dexmedetomidine 5 mcg/kg given intramuscularly, resulted in a good combination drug protocol which allow to handle cats easily and the use of low‐dose propofol for anaesthesia induction; however the analgesia obtained was not always adequate.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
