Parâmetros eletrocardiográficos e efeitos da xilazina e da detomidina em asininos nordestinos.

Abstract

The Northeastern donkeys are rustic, resistant to arid environments and high temperatures and animals still little studied, the anesthetic point. This dissertation consists of two unique chapters based on electrocardiographic examination and determination of the effects of detomidine and xylazine in different doses, in northeastern donkeys. In the first chapter it was investigated the feasibility of the technique and characterize the hexaxial lead system on frontal plane in northeastern adults donkeys and to establish reference values of normality for the electrocardiographic variables. The study was carried out in 40 healthy adult northeastern donkeys, mean age 7±4 years, mean weight 120±16 kg, respectively. The mean heart rate was 39 ± 7 bpm, predominant cardiac rhythm was sinusal and cardiac axis ranged between 70 and 180°. Various morphologies P wave (bifid, simple and biphasic), QRS complex (QS , R , qR, QR , Qr , RS , RS, RS , R'R , Rr ' , qrs , Qrs and r'sR) and T wave (single and biphasic) were found as well various polarity ( +, + / -, -, /+). It was concluded that the technique electrocardiographic of hexaxial leads system on the frontal plane is feasible in docile donkeys, aVR is the closest derivation to the mean vector of ventricular depolarization, and DII is the more uniform derivation. In the second chapter we compared the effects of detomidine and xylazine in different doses in six northeastern donkeys. Each animal participated, randomly and every seven days, of all the following groups: administration of xylazine 10% at doses of 0.8 mg/kg (xylazine Group 0.8 GX0.8), 1.0 mg/kg (GX1.0) and 1.2 mg/kg (GX1.2), administration of detomidine 1% at doses of 0.02 mg/kg (group detomidine 0.02 GD0.02), 0.04 mg/kg (GD0.04) and 0.06 mg/kg (GD0.06). All drugs were administered intravenously. The heart rates (HR), respiratory rate (f), rectal temperature (RT), mean arterial pressure (MAP), blood glucose, sedation, degree of ataxia, penile prolapse, muzzletoground distance, antinociceptive effects and occurrence of cardiac arrhythmias and urination were measured. The period of sedation was higher in GD0.02, GD0.04 and GD0.06. The muzzletoground distance was significantly reduced in all groups at five minutes after administration of the sedative, remaining lower for longer in GD0.06. Degree of ataxia in GX1.0 was higher than in GX0.8 and GX1.2, equivalent to the GD0.04 and GD0.06. Antinociception lasted 30 minutes in GD0.06 and 10 minutes for the other groups. HR reduction occurred in GD0.02 and GD0.04 and atrioventricular block in all groups. A decrease in TR groups was observed in GX1.2, GD0.02, GD0.04 and GD0.06. The f decreased in all groups. MAP increased in GD0.02, GD0.04 and GD0.06 from five to 20, 30 and 10 minutes after administration detomidine, respectively. Hyperglycemia occurred in GD0.02, GD0.04 and GD0.06, for up to 120 minutes. The increase of urination was greater in GD0.06 (2.2 ± 0.8) than in GX0.8 (0.8 ± 0.4). All doses produced sedation, with the lowest and highest sedative effects been obtained respectively with xylazine 0.8 mg/kg and detomidine 0.06 mg/kg. Both drugs promoted antinociception of short duration and mild cardiorespiratory changes, however detomidine caused greater hypertension and hypothermia effects. It is concluded that the studies included in this thesis produced new information about the ECG and sedation with xylazine and detomidine in northeastern donkeys.