Effects of ketamine‐diazepam and ketamine‐acepromazine combinations on intraocular pressure in rabbits

ObjectiveTo determine the effects of ketamine-diazepam and ketamine-acepromazine combinations on intraocular pressure (IOP) in rabbits.Study designRandomized clinical trial.AnimalsSixteen adult New Zealand white rabbits approximately one year old, weighing 2.3 ± 0.2 kg were used in this study.MethodsThe animals were randomly divided into two groups of eight each (KA and KD). The pre-treatment IOPs were recorded in both groups (T0). All rabbits in group KA received intramuscular ketamine-acepromazine (ketamine 30 mg kg^?1+ acepromazine 0.5 mg kg^?1). Ketamine-diazepam (ketamine 30 mg kg^?1 + diazepam 1 mg kg^?1) was administered intramuscularly in members of group KD. The IOP values were measured at 5 (T₅), 15 (T₁₅), and 20 (T₂₀) minutes after drug administration in both treatment groups.ResultsSignificant increases in IOP values were observed in both treatment groups at T_5, T₁₅, and T₂₀ in comparison to the baseline values. In group KA the mean ± SD IOP at T_5, T₁₅, and T₂₀ were 37 ± 13 (p < 0.001), 35 ± 4 (p < 0.001) and 34 ± 4 mmHg (p < 0.001). The post-treatment mean ± sd values in group KD were 23 ± 8 (p = 0.002), 23 ± 5 (p < 0.001) and 23 ± 6 mmHg (p = 0.001) at 5, 15, and 20 minutes respectively.Conclusion and clinical relevanceBoth ketamine-diazepam and ketamine-acepromazine combinations increased IOP after intramuscular administration in rabbits.     

Effect of propofol and ketamine-diazepam on intraocular pressure in healthy premedicated dogs

Objective

To compare the effect of propofol and ketamine/diazepam for induction following premedication on intraocular pressure (IOP) in healthy dogs.

Effects of medetomidine and xylazine on intraocular pressure and pupil size in healthy Beagle dogs

ObjectiveTo determine the effects of intramuscular (IM) administration of medetomidine and xylazine on intraocular pressure (IOP) and pupil size in normal dogs.Study designProspective, randomized, experimental, crossover trial.AnimalsFive healthy, purpose-bred Beagle dogs.MethodsEach dog was administered 11 IM injections of, respectively: physiological saline; medetomidine at doses of 5, 10, 20, 40 and 80 μg kg⁻¹, and xylazine at doses of 0.5, 1.0, 2.0, 4.0 and 8.0 mg kg⁻¹. Injections were administered at least 1 week apart. IOP and pupil size were measured at baseline (before treatment) and at 0.25, 0.50, 0.75, 1, 2, 3, 4, 5, 6, 7, 8 and 24 hours post-injection.ResultsA significant decrease in IOP was observed at 6 hours after 80 μg kg⁻¹ medetomidine compared with values at 0.25 and 0.50 hours, although there were no significant changes in IOP from baseline. In dogs treated with 8.0 mg kg⁻¹ xylazine, significant reductions in IOP were observed at 4 and 5 hours compared with that at 0.25 hours after administration. In dogs treated with 5, 10, 20 and 40 μg kg⁻¹ medetomidine and 0.5, 1.0 and 2.0 mg kg⁻¹ xylazine, there were no significant changes in IOP. Pupil size did not change significantly after any of the medetomidine or xylazine treatments compared with the baseline value.Conclusions and clinical relevanceLow or moderate doses of medetomidine or xylazine did not induce significant changes in IOP or pupil size. In contrast, high doses of medetomidine or xylazine induced significant changes up to 8 hours after treatment, but values remained within the normal canine physiological range. The results of this study suggest a lack of significant change in IOP and pupil size in healthy dogs administered low or moderate doses of xylazine or medetomidine.     

Comparison of intraocular pressure and pupil diameter after sedation with either acepromazine or dexmedetomidine in healthy dogs

Objective

To compare intraocular pressure (IOP) and pupillary diameter (PD) following intravenous (IV) administration of dexmedetomidine and acepromazine in dogs.

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye

OBJECTIVE: To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats. ANIMALS STUDIED: The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size. RESULTS: Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (相似文献   

The effects of ketamine‐midazolam anesthesia on intraocular pressure in clinically normal dogs

Objective To determine the effects of intravenous ketamine‐midazolam anesthesia on intraocular pressure (IOP) in ocular normotensive dogs. Animals Thirteen adult mixed‐breed dogs. Procedures Dogs were randomly assigned to treatment (n = 7) and control (n = 6) groups. Dogs in the treatment group received intravenous ketamine 15 mg/kg and midazolam 0.2 mg/kg and dogs in the control group received intravenous saline. The time of intravenous drug injection was recorded (T₀). Measurements of IOP were then repeated 5 min (T₅) and 20 min (T₂₀) following the intravenous administration of ketamine‐midazolam combination and saline in both groups. Results Measurements showed normal IOP values in both groups. The mean ± SD baseline IOP values for treatment and control groups were 13.00 ± 1.47 and 10.33 ± 2.20, respectively. For baseline IOP values, there was no significant difference between treatment and control groups (P = 0.162). In the treatment group, the subsequent post‐treatment mean ± SD values were 15.64 ± 2.17 (5 min), and 14.92 ± 1.98 (20 min). There was no evidence of statistical difference between baseline values and post‐treatment values after treatment with ketamine‐midazolam (P₅ = 0.139; P₂₀ = 0.442). In control eyes, the mean ± SD values at 5 and 20 min were 10.41 ± 2.01 and 10.16 ± 1.69, respectively. There was no significant difference between baseline values and post‐treatment values in control group (P₅ = 1.000; P₂₀ = 1.000). Conclusion Ketamine‐midazolam combination has no clinically significant effect on IOP in the dog.     

The cardiopulmonary effects of anesthetic induction with isoflurane,ketamine‐diazepam or propofol‐diazepam in the hypovolemic dog

ObjectiveTo evaluate and compare the cardiopulmonary effects of induction of anesthesia with isoflurane (Iso), ketamine–diazepam (KD), or propofol–diazepam (PD) in hypovolemic dogs.Study designProspective randomized cross–over trial.AnimalsSix healthy intact, mixed breed, female dogs weighing 20.7 ± 4.2 kg and aged 22 ± 2 months.MethodsDogs had 30 mL kg^?1 of blood removed at a rate of 1.5 mL kg^?1 minute^?1 under isoflurane anesthesia. Following a 30–minute recovery period, anesthesia was reinduced. Dogs were assigned to one of three treatments: isoflurane via facemask using 0.5% incremental increases in the delivered concentration every 30 seconds, 1.25 mg kg^?1 ketamine and 0.0625 mg kg^?1 diazepam intravenously (IV) with doses repeated every 30 seconds as required, and 2 mg kg^?1 propofol and 0.2 mg kg^?1 diazepam IV followed by 1 mg kg^?1 propofol increments IV every 30 seconds as required. Following endotracheal intubation all dogs received 1.7% end–tidal isoflurane in oxygen. Cardiopulmonary variables were recorded at baseline (before induction) and at 5 or 10 minute intervals following endotracheal intubation.ResultsInduction time was longer in Iso (4.98 ± 0.47 minutes) compared to KD (3.10 ± 0.47 minutes) or PD (3.22 ± 0.45 minutes). To produce anesthesia, KD received 4.9 ± 2.3 mg kg^?1 ketamine and 0.24 ± 0.1 mg kg^?1 diazepam, while PD received 2.2 ± 0.4 mg kg^?1 propofol and 0.2 mg kg^?1 diazepam. End–tidal isoflurane concentration immediately following intubation was 1.7 ± 0.4% in Iso. Arterial blood pressure and heart rate were significantly higher in KD and PD compared to Iso and in KD compared to PD. Arterial carbon dioxide partial pressure was significantly higher in PD compared to KD and Iso immediately after induction.Conclusions and clinical relevanceIn hypovolemic dogs, KD or PD, as used in this study to induce anesthesia, resulted in less hemodynamic depression compared to isoflurane.     

Effect of single- and multiple-dose 0.5% timolol maleate on intraocular pressure and pupil size in female horses

OBJECTIVE: To determine the effect of single and multiple-dose 0.5% timolol maleate on intraocular pressure (IOP) and pupil size between 8 AM and 8 PM. Animals Nine female horses with normotensive eyes. Procedure IOP, horizontal and vertical pupil size were measured on a single day, between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. A single dose of 0.5% timolol maleate was applied to both eyes immediately after the first measurement at 8 AM. IOP and pupil size were measured at 8 AM and 4 PM in a 5-day experiment of twice-daily application of 0.5% timolol maleate. RESULTS: A significant decrease in IOP from 24.9 +/- 4.2 mmHg prior to application of timolol maleate to 20.7 +/- 3.1 mmHg (4.2 mmHg = 17%) was observed 8 h after single-dose application. A significant decrease in horizontal pupil size (2.0 mm = 11%) was present 6 h after single-dose application. In the multiple-dose experiment, a significant decrease in IOP was present on days 4 and 5 as compared to IOP measured prior to application of timolol maleate. A significant decrease in horizontal and vertical pupil size was present throughout the 5-day study as compared to the values obtained prior to treatment. CONCLUSIONS: 0.5% timolol maleate significantly decreased IOP and pupil size in normo-tensive eyes of this group of female horses in both single and multiple twice daily applications.     

Effect of Coherin™ on intraocular pressure,pupil size and heart rate in the glaucomatous Beagle: a pilot study

Objective To evaluate effects of Coherin? on intraocular pressure (IOP), pupil size (PS), and heart rate (HR) in glaucomatous Beagles in single‐dose studies in a pilot study. Materials and methods Intraocular pressure, PS, and HR were measured in eight glaucomatous Beagles. One randomly chosen eye received single 50 μL doses of differing concentrations of Coherin? (treated eye) or vehicle (placebo‐treated eye), and the fellow eye served as the untreated control. After the first measurements, a single dose of either Coherin? or sterile water vehicle was instilled in the drug and placebo eyes, respectively. Results The mean ± SEM diurnal changes in IOP after 0.005%, 0.01%, 0.2%, 0.284%, 1%, 2%, and 4% topical Coherin? once daily were 7.6 ± 3.2 mmHg, 15.5 ± 5.3 mmHg, 11.2 ± 4.4 mmHg, 11.8 ± 4.4 mmHg, 19.1 ± 3.8 mmHg, 5.0 ± 1.8 mmHg, and 8.8 ± 2.8 mmHg, respectively. The declines in IOP were significantly different (P < 0.05) from the untreated control eyes with the 0.2% and 0.284% Coherin?‐treated eyes and suggestive for 1% Coherin? concentrations. No signs of irritation, significant PS, and HR changes were detected in the Coherin?‐treated eyes. Conclusion Of seven different concentrations, 2% and 0.248% Coherin? produced significant declines in IOP in the glaucomatous beagle in single‐dose studies when compared to both untreated control and placebo‐treated eyes. One percent Coherin? solution produced significant IOP decreases compared with the placebo‐treated eye but not the untreated control eyes. No local ocular irritation, PS and HR changes were observed in Coherin?‐treated eyes. This pilot study suggests that topical Coherin? has potential as an ocular hypotensive agent.     

The relationship of cataract maturity to intraocular pressure in dogs

Objective To determine the distribution of intraocular pressure, as measured by applanation tonometry, in dogs with cataracts, and compare these tonometric results to the different stages of cataract formation (incipient, immature, mature, and hypermature). Animals studied Retrospection study of canine clinical patients (86 dogs). Procedures All records of dogs presented from 1991 to 1996 to the university veterinary medical teaching hospital for diagnosis of cataracts and evaluation for cataract surgery were reviewed. The tonometric measurements from the initial ophthalmic examination were selected in cataractous and nonglaucomatous eyes either receiving no topical or no systemic medications. The stage of cataracts was based on the degree of opacification, tapetal reflection, clinical vision, and visibility of the ocular fundus by indirect ophthalmoscopy. The distribution of tonometric results were grouped by the cataract maturity, and compared by anova and Tukey’s general linear tests. Results Intraocular pressure with incipient cataracts ranged from 9 to 17 mmHg (mean 12.7 ± 1.2 mmHg). Intraocular pressure with immature cataracts ranged from 3 to 27 mmHg (mean 13.6 ± 0.6 mmHg). For the mature cataracts, IOP ranged from 5 to 22 mmHg (mean 11.9 ± 0.7 mmHg). For the hypermature cataract group, IOP ranged from 4 to 23 mmHg (mean 10.8 ± 0.6 mmHg). Comparison of the tonometric results among the different stages of cataract formation indicated a significant difference (P = 0.0086) between only the immature and hypermature groups. Conclusions Intraocular pressure in lens‐induced uveitis (LIU) is lowered but the relationship to the stage of cataract maturity is less clear. Significant tonometric differences were present between the immature and hypermature cataract groups, but these differences are too small to be clinically useful. Decreased intraocular pressure of dogs with all stages of cataract formation suggests concurrent LIU during all stages of cataract formation, especially with the mature and hypermature stages. The average tonometric measurements in dogs with these cataracts were about two standard deviations below the mean IOP reported in normal dogs.     

The effect of dorzolamide 2% on circadian intraocular pressure in cats with primary congenital glaucoma

Objective To determine the extent of fluctuation in circadian intraocular pressure (IOP) and the efficacy of topical dorzolamide 2% q 8 h in lowering IOP and blunting circadian fluctuation in IOP in glaucomatous cats. Animals studied Seven adult cats with primary congenital glaucoma (PCG). Procedures Measurements of IOP and pupil diameter were obtained for both eyes (OU) of each cat q 4 h for 12 days. Cats were housed in a laboratory animal facility with a 12‐h light:dark cycle. Baseline values were established for 2 days. For the next 5 days, placebo (1.4% polyvinyl alcohol) was administered OU q 8 h. Dorzolamide 2% was then administered OU q 8 h for a further 5 days. A multivariate mixed linear model was fitted to the data, with parameters estimated from a Bayesian perspective. The 4 am time point was selected as the reference for the purposes of comparisons. Results Estimated mean IOP for the reference time point pre‐treatment was symmetric (about 33 mmHg OU). In all cats, IOP was significantly lower during the diurnal phase, relative to the 4 am measurements, with highest IOP observed 2–6 h after the onset of the dark phase. Circadian fluctuations in IOP were dampened during the treatment period. There was a significant decrease in IOP in all cats during the dorzolamide treatment period (estimated mean for the treatment period reference = 17.9 mmHg OU). Conclusions Topical dorzolamide 2% q 8 h is effective in reducing IOP and IOP fluctuation in cats with PCG.     

A systematic review of the effects of injectable sedative and anesthetic drugs and inhalant anesthetics on intraocular pressure in the dog

ObjectiveThe purpose of this systematic review was to summarize the results of studies that have determined the effect of injectable and inhalant drugs used in anesthesia on intraocular pressure (IOP) in dogs.Databases usedA comprehensive search of research literature was performed without language restriction. The search utilized the PubMed, CAB Abstracts and the University of Georgia’s Galileo electronic databases using a combination of free text terms ‘Ophthalmology’, ‘Intraocular Pressure’, ‘Anesthetic’, ‘Anesthesia’, ‘Canine’ or ‘Dog’. The time frame searched was from 1970 to October 2018. Any published research paper that dealt with sedatives or anesthetics administered systemically and the canine eye was evaluated.ConclusionsThe effects of many anesthetic drugs in dogs with ocular pathology are largely unknown. Many anesthetic drugs do not induce clinically relevant changes in IOP in dogs with normal eyes, although some studies demonstrated results with statistically significant changes. The dose, route of administration, experimental conditions, drug combinations, timing of measurements, measurement technology and setting or individual animal characteristics may all produce some heterogeneity in results from multiple studies.     

Effect of anesthetic induction with propofol,alfaxalone or ketamine on intraocular pressure in cats: a randomized masked clinical investigation

ObjectiveTo compare the effect of propofol, alfaxalone and ketamine on intraocular pressure (IOP) in cats.Study designProspective, masked, randomized clinical trial.AnimalsA total of 43 ophthalmologically normal cats scheduled to undergo general anesthesia for various procedures.MethodsFollowing baseline IOP measurements using applanation tonometry, anesthesia was induced with propofol (n = 15), alfaxalone (n = 14) or ketamine (n = 14) administered intravenously to effect. Then, midazolam (0.3 mg kg^?1) was administered intravenously and endotracheal intubation was performed without application of topical anesthesia. The IOP was measured following each intervention. Data was analyzed using one-way anova and repeated-measures mixed design with post hoc analysis. A p-value <0.05 was considered significant.ResultsMean ± standard error IOP at baseline was not different among groups (propofol, 18 ± 0.6; alfaxalone, 18 ± 0.7; ketamine, 17 ± 0.5 mmHg). Following induction of anesthesia, IOP increased significantly compared with baseline in the propofol (20 ± 0.7 mmHg), but not in the alfaxalone (19 ± 0.8 mmHg) or ketamine (16 ± 0.7 mmHg) groups. Midazolam administration resulted in significant decrease from the previous measurement in the alfaxalone group (16 ± 0.7 mmHg), but not in the propofol group (19 ± 0.7 mmHg) or the ketamine (16 ± 0.8 mmHg) group. A further decrease was measured after intubation in the alfaxalone group (15 ± 0.9 mmHg).Conclusions and clinical relevancePropofol should be used with caution in cats predisposed to perforation or glaucoma, as any increase in IOP should be avoided.     

Effect of orally administered hydrocortisone on intraocular pressure in nonglaucomatous dogs

OBJECTIVE: To determine the effect of oral hydrocortisone on intraocular pressure (IOP) in ocular normotensive dogs. ANIMALS STUDIED: Seventeen ocular normotensive dogs. Procedures Dogs were randomly assigned to treatment (n = 9) and control (n = 8) groups. Dogs in the treatment group received hydrocortisone, 3.3 mg/kg PO every 8 h, and dogs in the control group received gelatin capsule placebo PO every 8 h for 5 weeks. Applanation tonometry was performed on both eyes of all dogs prior to treatment and then once weekly for 5 weeks during hydrocortisone treatment. RESULTS: No significant effect of treatment was noted for right (P = 0.1013) or left (P = 0.1157) eyes during the treatment period, nor was there significant interaction of treatment by week for the right (P = 0.9456) or left (P = 0.3577) eyes. A significant rise in IOP over the treatment period was noted in both right (P < 0.0001) and left (P = 0.0006) eyes of both groups, but was unrelated to treatment. CONCLUSION: Orally administered hydrocortisone does not significantly increase IOP in nonglaucomatous dogs when administered over a 5-week period.     

Effect of topical atropine on intraocular pressure and pupil diameter in the normal horse eye

The objective was to determine whether topically administered 1% atropine would alter intraocular pressure. The animals studied were four healthy adult horses. Intraocular pressure and pupil diameter were measured prior to and during a 2-day period of treatment with 1% atropine sulfate. No significant changes in intraocular pressure occurred as a result of the treatment with atropine. Pupil diameter increased significantly after atropine was applied. Available information on the outflow of aqueous humor from the horse eye suggests that atropine might reduce intraocular pressure in the horse by increasing uveoscleral outflow. This could prove beneficial in the treatment of equine glaucoma. We could not confirm a significant pressure-lowering effect of atropine. It is possible, however, that a longer treatment period may be required or that atropine may have a more profound effect on glaucomatous globes.