Evaluación de la inducción anestésica con Tiletamina/Zolazepan en perros sometidos a diferentes protocolos de premedicación

the anesthetic effects of a single intravenous (iv) dose of tiletamine/zolazepam (t/z) combination in dogs with different preanesthetic protocols were evaluated. sixteen cross-bred dogs (4 dogs/group) of both sexes were chosen and randomly allocated into four different treatments (t): treatment 1 (t1): dogs received t/z (7.0 mg/kg iv); treatment 2 (t2): dogs received an intramuscular (im) dose of xylazine (0.2 mg/kg) plus t/z; treatment 3 (t3): dogs received acepromazine (0.25 mg/kg, im) plus t/z; treatment 4 (t4): dogs received butorphanol (0.1 mg/kg, im) plus t/z. ten min before onset of t, animals were given atropine (0.04 mg/kg). the following variables were assessed using non-invasive methods: mean arterial pressure (map); heart rate (hr); body temperature (bt); pulse oxymetry (spo2); respiratory rate (rr); time for induction (ti); and time for general (ta) anesthesia. measurements were done before, during (every 5 min for 20 min), and after ta. results show that map was similar in t1, t3, and t4, regardless the preanesthetic protocol used, being higher (p<0.05) in t2, compared to t3. the hr slightly rose after administration of t/z in all t, with lower values (p<0.05) for t2 at the beginning of measurement. the bt dropped (p<0.05) in dogs under t3, compared to t1. similarly, xylazine induced a lower bt during recovery. the spo2 was reduced (p<0.05) in t3, while rr was similar in all t, with higher values before administration of t/z in t3, when compared to t2 and t4. both ti and ta were similar among t; however, the administration of some of the preanesthetic protocols tended to reduce ti and increased ta. it is concluded that in atropinized dogs, the preanesthetic protocols with xylazine, acepromazine, or butorphanol, does not cause any significant changes in the effects of anesthetic induction with t/z, when the physiological variables are evaluated by non-invasive methods.