The aim of this study was to assess the effects of four different drugs used for anaesthesia premedication on intraocular pressure and pupil size in dogs. A prospective, randomised, double-blind clinical study was carried out. The subjects were forty client-owned healthy dogs (20 males and 20 females), aged 8.0 ± 2.9 years, with body weights of 11.8 ± 8.5 kg (mean ± SD) and without ocular abnormalities that were scheduled for periodontal treatment. Animals were randomly allocated into four groups and received intravenously either medetomidine 0.01 mg/kg, acepromazine 0.02 mg/kg, fentanyl 0.01 mg/kg or butorphanol 0.2 mg/kg. Intraocular pressure, pupil size, heart rate, respiratory frequency and systolic and diastolic arterial pressures were measured prior to (baseline) and at five and 10 minutes after premedication (T5, T10). Data were analysed by Anderson-Darling, Bartlett’s, ANOVA and Dunnett’s tests (P < 0.05). Significant increases of intraocular pressure were observed at T5 and T10 in the fentanyl group. Significant decreases of pupil size at T5 and T10 were detected in the fentanyl, butorphanol and medetomidine groups. In the fentanyl group, heart rate dropped significantly at T10, while respiratory frequency was elevated at T5 and T10. In the medetomidine group, heart rate and respiratory frequency were decreased at T5 and T10. In the butorphanol group, systolic arterial pressure was decreased at T5 and diastolic arterial pressure was decreased at T5 and T10. In the acepromazine group, systolic arterial pressure was decreased at T10. Within ten minutes after intravenous administration in healthy dogs, fentanyl significantly increased intraocular pressure and fentanyl, butorphanol and medetomidine decreased pupil size.
ABSTRACT:The present prospective, randomised, double-blinded clinical study was designed to investigate the commonly used anaesthetic combinations of dexmedetomidine-propofol-isoflurane and medetomidine-propofolisoflurane on intraocular pressure and pupil size in dogs. Forty client-owned healthy dogs with no ocular abnormalities, average body weight of 25.7 ± 13.1 kg (mean ± SD) and aged 3.7 ± 2.7 years, were enrolled. Twenty four males and 16 females were included. Dogs were allocated randomly to receive dexmedetomidine i.v. at 0.005 mg/ kg, dexmedetomidine at 0.01 mg/kg, medetomidine at 0.01 mg/kg or medetomidine at 0.02 mg/kg. Ten minutes later anaesthesia was induced in all dogs with propofol and maintained with isoflurane in oxygen-air. Intraocular pressure, pupil size, heart rate, respiratory frequency and arterial blood pressures (SAP, DAP) were measured prior to (baseline) and at 10 (before propofol), 20, 30, 40, 50 and 60 min after dexmedetomidine or medetomidine administration. Oxygen saturation of haemoglobin (SpO 2 ) and end-tidal CO 2 concentration (EtCO 2 ) was monitored following anaesthesia induction. Data were analysed using Anderson-Darling and Bartlett's tests for data distribution and homogeneity of variance confirmation and ANOVA followed by Dunnett's tests for multiple comparisons. Changes were considered significant when P < 0.05. Following drug administration, pupil size, heart rate and respiratory frequency decreased significantly within groups, but did not differ between groups. No significant changes in intraocular pressure, SAP and DAP within and between groups, and SpO 2 or EtCO 2 between groups, were observed. Comparable doses of dexmedetomidine or medetomidine combined with propofol and isoflurane induced reductions in pupil size, respiratory frequency and heart rate, however, without a significant influence on intraocular pressure or arterial blood pressure.
The goal of the presented research was to assess the influence of continuously administered fentanyl on the intraocular pressure, pupil size and aqueous tear production in dogs. A prospective, randomised, double “blind” clinical study was performed. Twenty-five non-painful dogs, 13 breeds, a body weight of 10.0 ± 5.4 kg (mean ± SD) and age of 6.5 ± 3.3 years, 12 males and 13 females with no ocular abnormalities were randomly allocated into two groups receiving an intravenous injection of saline (SAL) 0.3 ml/kg followed by an infusion 2 ml/kg/h or an intravenous injection of fentanyl (FEN) 0.005 mg/kg (diluted in 0.3 ml/kg) followed by an infusion 0.005 mg/kg/h (diluted in 2 ml/kg/h). The intraocular pressure (IOP), pupil size (PS), pulse rate (PR), respiratory frequency (f<sub>R</sub>) and systolic and diastolic arterial pressures (SAP, DAP) were measured before (baseline) and at 2, 5, 10, 20 and 30 minutes after the premedication. The Schirmer Tear Test I (STT-I) was measured prior to and at 30 min after the premedication. The data were analysed by Bartlett’s, Anderson-Darling and Dunnett’s tests, the t-test and an analysis of variance (ANOVA) (P < 0.05). Relative to the baseline, in the fentanyl group, the PS was significantly decreased at all time points, the PR was significantly decreased at T<sub>30</sub> and the f<sub>R</sub> was significantly decreased at T<sub>5</sub>, T<sub>10</sub>, T<sub>20</sub> and T<sub>30</sub>. There were no other significant changes in the IOP, STT-I, SAP and DAP relative to the baseline. Compared to the control group, in the fentanyl group, the PS was significantly smaller at T<sub>2</sub>, T<sub>5</sub>, T<sub>10</sub>, T<sub>20</sub> and T<sub>30</sub>, the PR was significantly lower at T<sub>2</sub>, T<sub>20</sub> and T<sub>30</sub> and the f<sub>R</sub> was significantly higher at T<sub>20</sub>. Within thirty minutes of a constant rate infusion of fentanyl in the healthy non-painful dogs, the intraocular pressure and aqueous tear production were not affected. However, the fentanyl significantly decreased pupil size. This fact should be considered, when planning analgesia where miosis is undesirable.
The present study determined markers of oxidative and antioxidative activity in dog females affected with mammary gland tumour compared to healthy ones. The effect of additional vitamin E supplementation on oxidative and antioxidative status was evaluated as well. The study included 29 female dogs divided into 4 groups (groups 1 and 2 included females with a mammary gland tumour; groups 3 and 4 included healthy female dogs). Additional vitamin supplement containing α-tocopherol was given to the females of groups 1 and 4. Dogs from groups 1 and 2 were anaesthetized before surgery (ovariohysterectomy and mastectomy); anaesthesia was used also in group 3, but without performeing surgery. The content of vitamin E (free α-tocopherol), marker of antioxidative status, was measured in blood serum by liquid chromatography. The concentration of thiobarbituric acid reactive substances, marker of oxidative status, in serum and concentrations of protein and non-protein thiol groups, markers of oxidative and antioxidative status, in blood serum and in red blood cells were measured colorimetrically. In females with a mammary gland tumour from group 2, concentration of thiobarbituric acid reactive substances was significantly higher than 14 days after surgery and compared to healthy ones as well. In females with a mammary gland tumour from group 2, concentration of protein thiol groups in serum was significantly lower and concentration of non-protein thiol groups in serum was significantly higher than in healthy controls. The values of protein thiols in erythrocytes in females with mammary gland tumour from group 1 were significantly higher before supplementation with vitamin E. The present study revealed that females with a mammary gland tumour were more burdened with oxidative stress compared to healthy dogs. The removal of the mammary gland tumour led to improvement of oxidative and antioxidative status. This is the first report focusing on the effect of additional α-tocopherol supplementation on reducing oxidative stress by increasing antioxidative activity in females affected with mammary gland tumour; however, we did not prove it. , ovariohysterectomy, α-tocopherol, thiobarbituric acid reactive substances, protein and non-protein thiol groups Mastectomy
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