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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare analgesia provided by carprofen and tramadol in dogs after enucleation.

Design—Randomized, masked clinical trial.

Animals—43 dogs.

Procedures—Client-owned dogs admitted for routine enucleation were randomly assigned to receive either carprofen or tramadol orally 2 hours prior to surgery and 12 hours after the first dose. Dogs were scored for signs of pain at baseline (ie, before carprofen or tramadol administration) and at 0.25, 0.5, 1, 2, 4, 6, 8, 24, and 30 hours after extubation. Dogs received identical premedication and inhalation anesthesia regimens, including premedication with hydromorphone. If the total pain score was ≥ 9 (maximum possible score of 20), there was a score ≥ 3 in any of 5 behavioral categories (highest score possible per category was 3 or 4), or the visual analog scale (VAS) score was ≥ 35 (maximum possible score of 100) combined with a palpation score > 0, rescue analgesia (hydromorphone) was administered and treatment failure was recorded.

Results—No differences were found in age, sex, or baseline pain scores between groups. Significantly more dogs receiving tramadol required rescue analgesia (6/21), compared with dogs receiving carprofen (1/22). Pain and VAS scores decreased linearly over time. No significant differences were found in pain or VAS scores between groups at any time point (dogs were excluded from analysis after rescue).

Conclusions and Clinical Relevance—Results of this study suggested that carprofen, with opioid premedication, may provide more effective postoperative analgesia than tramadol in dogs undergoing enucleation.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the efficacy of a retrobulbar bupivacaine nerve block for postoperative analgesia following eye enucleation in dogs.

Design—Randomized controlled trial.

Animals—22 dogs.

Procedures—Client-owned dogs admitted to the hospital for routine eye enucleation were enrolled with owner consent and randomly assigned to a treatment (bupivacaine hydrochloride) or control (saline [0.9% NaCl] solution) group. Baseline subjective pain scores were recorded. Anesthesia consisted of hydromorphone and midazolam preoperatively, thiopental or propofol for induction, and isoflurane in oxygen for maintenance. An inferior-temporal palpebral retrobulbar injection of either saline solution or bupivacaine was administered. Transpalpebral eye enucleation was performed. Pain scores were recorded at 0.25, 0.5, 1, 2, 4, 6, 8, and 24 hours after extubation (time 0) by observers masked to treatment groups. Dogs were given hydromorphone (0.2 mg/kg [0.09 mg/lb], IM or IV) as a rescue analgesic if the subjective pain score totaled ≥ 9 (out of a maximum total score of 18) or ≥ 3 in any 1 category.

Results—9 of 11 control dogs required a rescue dose of hydromorphone, but only 2 of 11 dogs in the bupivacaine treatment group required rescue analgesia. Mean time to treatment failure (ie, administration of rescue analgesia following extubation) was 0.56 hours (95% confidence interval, 0.029 to 1.095 hours) for the 11 dogs that received hydromorphone.

Conclusions and Clinical Relevance—Retrobulbar administration of bupivacaine in dogs in conjunction with traditional premedication prior to eye enucleation was an effective form of adjunctive analgesia and reduced the need for additional postoperative analgesics.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare hydromorphone with oxymorphone, with or without acepromazine, for preanesthetic sedation in dogs and assess changes in plasma concentration of histamine after drug administration.

Design—Randomized clinical study.

Animals—10 healthy mixed-breed dogs.

Procedure—Dogs were treated IM with hydromorphone (group H), oxymorphone (group O), hydromorphone with acepromazine (group H/A), or oxymorphone with acepromazine (group O/A). Sedation score, heart rate, respiratory rate, systolic blood pressure, and oxygen saturation were recorded at baseline immediately after drug administration (T0) and every 5 minutes for 25 minutes (T25). Plasma histamine concentration was measured at baseline and T25.

Results—Sedation was similar between groups H and O at all times. Sedation was significantly greater for groups H/A and O/A from T10 to T25, compared with other groups. Systolic blood pressure was significantly reduced at T25 in group H/A, compared with group H, and in group O/A, compared with group O. Prevalence of panting at T25 was 50% for groups H and O, compared with 20% for group H/A and 30% for group O/A. By T25, heart rate was significantly lower in all groups. Oxygen saturation was unaffected by treatment. Mean ± SD plasma histamine concentration was 1.72 ± 2.69 ng/ml at baseline and 1.13 ± 1.18 ng/ml at T25. There was no significant change in plasma histamine concentration in any group.

Conclusions and Clinical Relevance—Hydromorphone is comparable to oxymorphone for preanesthetic sedation in dogs. Sedation is enhanced by acepromazine. Neither hydromorphone nor oxymorphone caused an increase in plasma histamine concentration. (J Am Vet Med Assoc 2001;218:1101–1105)

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To describe onset and duration of neuromuscular blockade induced by mivacurium chloride and its associated hemodynamic effects at 3 dosages in healthy dogs.

Animals

7 Labrador Retrievers.

Procedure

Anesthesia was induced with thiopental and maintained with halothane in oxygen, and dogs were mechanically ventilated to end-tidal PCO2 between 35 and 40 mm Hg. Core temperature, end-tidal PCO2 , and halothane concentration were kept constant throughout the experiment. Neuromuscular function was assessed by evaluation of the train-of-four response to a supramaximal electrical stimulus of 2 Hz applied to the ulnar nerve every 10 seconds. Blood for determination of plasma cholinesterase activity was obtained prior to administration of mivacurium, a bolus of which was administered IV, using a randomized Latin-square design for dosages of 0.01, 0.02, and 0.05 mg/kg of body weight.

Results

All dogs had typical plasma cholinesterase activity. After administration of mivacurium, differences were not evident between groups in heart rate, systolic, mean, or diastolic blood pressure, change at any time in heart rate, systolic, mean, or diastolic blood pressure, or pH. Interval from onset to 100% neuromuscular blockade was 3.92 ± 1.70, 2.42 ± 0.53, and 1.63 ± 0.25 minutes at dosages of 0.01, 0.02, and 0.05 mg/kg, respectively. Duration of measurable neuromuscular blockade was 33.72 ± 12.73, 65.38 ± 12.82, and 151.0 ± 38.50 minutes, respectively. Time of onset and duration of effect differed significantly among dosages.

Conclusions and Clinical Relevance

Mivacurium provides good hemodynamic stability at the dosages tested. In dogs, this drug has a rapid onset and long duration of effect. (Am J Vet Res 1999;60:1047-1050)

Free access
in American Journal of Veterinary Research

Summary

Quantitative electroencephalography was assessed in 6 dogs anesthetized with 1.8% end-tidal halothane, under conditions of eucapnia, hypocapnia, and hypercapnia. Ventilation was controlled in each condition. Heart rate, arterial blood pressure, core body temperature, arterial pH, blood gas tensions, end-tidal CO2 tension, and end-tidal halothane concentration were monitored throughout the study. A 21-lead linked-ear montage was used for recording the eeg. Quantitative electroencephalographic data were stored on an optical disk for analysis at a later date. Values for absolute power of the eeg were determined for δ, θ, α, and β frequencies. Hypocapnia was achieved by hyperventilation. Hypercapnia was achieved by titration of 5% CO2 to the inspired gas mixture. Hypercapnia was associated with an increase in the absolute power of the δ band. Hypocapnia caused an increase in the absolute power of δ, θ, and α. frequencies. Quantitative electroencephalographic data appear to be altered by abnormalities in arterial carbon dioxide tension. Respiratory acidosis or alkalosis in halothane-anesthetized dogs may obscure or mimic electroencephalographic abnormalities caused by intracranial disease.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To develop and compare 3 techniques for retrobulbar injection of local anesthetic agents for ocular surgery and analgesia in dogs.

Design—Prospective study.

Animals—17 dogs (including 9 cadavers).

Procedures—Inferior-temporal palpebral (ITP), perimandibular, and combined superior-inferior peribulbar injection techniques were compared by assessing the distribution of latex after injection into the orbits of 5 canine cadavers; magnetic resonance imaging (MRI) evaluation of the distribution of contrast agent after injection in the retrobulbar space of 4 canine cadavers; and assessment of the efficacy and MRI evaluation of the anatomic distribution of injections of a lidocainecontrast agent mixture in 4 anesthetized, nonrecovery dogs. By use of the preferred technique (ITP), the ocular effects of lidocaine anesthesia were evaluated in 4 dogs; during a 2-week period after treatment, dogs underwent ophthalmic examination, Schirmer tear testing (STT), intraocular pressure (IOP) measurement, and Cochet–Bonnet esthesiometry.

Results—Of the 3 techniques, the ITP technique was the preferred method for retrobulbar administration of anesthetic agent in dogs because it was efficacious (pupil dilation and central rotation of the globe achieved in all eyes), easiest to perform, and provided thorough coverage of the intraconal retrobulbar space without complication. During the 2-week follow-up period, the ITP injection did not significantly affect STT, IOP, or Cochet-Bonnet esthesiometry values in dogs.

Conclusions and Clinical Relevance—In dogs, retrobulbar administration of anesthetic agents via the ITP technique is a potential alternative to systemic administration of neuromuscular blocking agents for ophthalmic surgery and provides the additional benefit of local ocular analgesia.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To compare the effectiveness of preoperative bupivacaine inferotemporal retrobulbar blocks to postoperative liposome-encapsulated bupivacaine (Nocita) line blocks for analgesia following enucleation.

ANIMALS

39 client-owned dogs (40 eyes) presenting to the Ophthalmology Service for enucleation.

METHODS

Dogs were randomly assigned to receive either a preoperative inferotemporal retrobulbar block with 0.5% bupivacaine or a peri-incisional line block with liposome-encapsulated bupivacaine (Nocita) at closure. Patients underwent unilateral enucleation and were hospitalized for 24 hours after surgery. Pain scores were performed by a masked observer with the Glasgow Composite Measure Pain Scale and the University of Wisconsin Ocular Pain Scale at 0.25, 0.5, 1, 2, 4, 6, 8, and 24 hours following surgery. Intraoperative use of blood pressure and anesthetic support mediations as well as need for rescue pain control were recorded and compared between groups.

RESULTS

There was no significant difference in rescue rates between treatment groups. When comparing the use of medical intraoperative heart rate, blood pressure, or anesthetic plane support, there were no significant differences in use between groups.

CLINICAL RELEVANCE

Use of preoperative bupivacaine retrobulbar blocks and postoperative Nocita line blocks were equally effective at postoperative pain control with similarly low complication rates.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine pharmacokinetic variables of mivacurium chloride after IV administration in dogs.

Animals

5 healthy Labrador Retrievers.

Procedure

Anesthesia was induced with thiopental and maintained with halothane in oxygen. Dogs were ventilated mechanically to an end-tidal PCO2 value between 35 and 40 mm Hg. Heart rate, direct blood pressure, and arterial pH were recorded throughout the experiment. Core temperature, end-tidal PCO2 , and halothane concentration were kept constant throughout the experiment. Paired blood samples for determination of plasma cholinesterase activity were collected prior to administration of a bolus of mivacurium (0.05 mg/kg of body weight), which was administered IV during a 2-second period. Arterial blood samples were obtained for determination of plasma mivacurium concentration 0, 1, 3, 5, 10, 30, 60, 120, 150, and 180 minutes after administration of mivacurium. Blood was collected into tubes containing EDTA and 0.25% echothiophate. Mivacurium concentration was determined, using reversed-phase high-performance liquid chromatography.

Results

For the trans-trans isomer, mean ± SEM volume of distribution was 0.18 ± 0.024 L/kg, median half-life was 34.9 minutes (range, 26.7 to 53.5 minutes), and clearance was 12 ± 2 ml/min/kg. For the cis-trans isomer, values were 0.31 ± 0.05 L/kg, 43.4 minutes (range, 31.5 to 69.3 minutes), and 15 ± 2 ml/min/kg, respectively. Values for the cis-cis isomer were not calculated, because it was not detectable in plasma 60 minutes after mivacurium administration in all 5 dogs.

Conclusions and Clinical Relevance

The trans-trans and cis-trans isomers of mivacurium have a long half-life and slow clearance in healthy dogs anesthetized with halothane. (Am J Vet Res 1999;60:1051-1054)

Free access
in American Journal of Veterinary Research