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- Author or Editor: Adriano B. Carregaro x
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Abstract
Objective—To investigate spontaneous locomotor activity (SLA) and antinociceptive effects of buprenorphine in horses.
Animals—6 healthy adult horses.
Procedures—Horses received each of 3 treatments (10 mL of saline [0.9% NaCl] solution, 5 μg of buprenorphine/kg, or 10 μg of buprenorphine/kg).Treatments were administered IV. Order of treatments was randomized, and there was a 10-day interval between subsequent treatments. Spontaneous locomotor activity was investigated in a behavioral box by use of infrared photoelectric sensors connected to a computer, which detected movement of each horse. Antinociceptive effect was investigated by hoof-withdrawal reflex latency (HWRL) and skin-twitching reflex latency (STRL) after painful stimulation with a heat lamp.
Results—Moderate excitement was observed in all horses from 5 to 10 minutes after the administration of both dosages of buprenorphine. The SLA increased significantly for 6 and 14 hours after IV administration of 5 and 10 μg of buprenorphine/kg, respectively. Values for HWRL increased significantly only at 30 minutes after injection of 5 μg of buprenorphine/kg, whereas STRL and HWRL each increased significantly from 1 to 6 hours (except at 2 and 4 hours) and 11 hours, respectively, after injection of 10 μg of buprenorphine/kg.
Conclusions and Clinical Relevance—IV injection of buprenorphine caused a dose-dependent increase in SLA, but only the dose of 10 μg/kg induced analgesia on the basis of results for the experimental method used.
Abstract
Objective—To investigate the effects of buprenorphine on cardiopulmonary variables and on abdominal auscultation scores in horses.
Animals—6 healthy adult horses.
Procedures—Horses were restrained in stocks and allocated to 2 treatments in a randomized crossover design, with 1-week intervals between each treatment. Saline (0.9% NaCl) solution was administered IV as a control, whereas buprenorphine (10 μg/kg, IV) was administered to the experimental group. Cardiopulmonary data were collected for 120 minutes after buprenorphine or saline solution administration. Abdominal auscultation scores were monitored for 2 and 12 hours after drug administration in the control and experimental groups, respectively.
Results—Following control treatment, horses remained calm while restrained in the stocks and no significant changes in cardiopulmonary variables were observed throughout the study. Buprenorphine administration caused excitatory phenomena (restlessness and head shaking). Heart rate, cardiac index, and arterial blood pressure were significantly increased after buprenorphine administration until the end of the observational period (120 minutes). Minimal changes were found in arterial blood gas tensions. Abdominal auscultation scores decreased significantly from baseline for 4 hours after buprenorphine administration.
Conclusions and Clinical Relevance— Buprenorphine induced excitement and hemodynamic stimulation with minimal changes in arterial blood gas tensions. These effects may impact the clinical use of buprenorphine in horses. Further studies are indicated to investigate the effects of buprenorphine on gastrointestinal motility and fecal output.
Abstract
OBJECTIVE To evaluate the antinociceptive efficacy of IM morphine sulfate or butorphanol tartrate administration in tegus (Salvator merianae).
ANIMALS 6 healthy juvenile (12- to 24-month-old) tegus (mean ± SD body weight, 1,484 ± 473 g).
PROCEDURES In a crossover study design, tegus were randomly assigned to treatment order, with a minimum washout period of 15 days between treatments. Each of 5 treatments was administered IM in a forelimb: saline (0.9% NaCl) solution (0.5 mL), morphine sulfate (5 or 10 mg/kg), or butorphanol tartrate (5 or 10 mg/kg). A withdrawal latency test was used to evaluate antinociception, with a noxious thermal stimulus applied to the plantar surface of the hind limb before (0 hours; baseline) and 0.5, 1, 2, 3, 4, 6, 12, and 24 hours after each treatment. Observers were unaware of treatment received.
RESULTS With saline solution, mean hind limb withdrawal latencies (interval to limb withdrawal from the thermal stimulus) remained constant, except at 12 hours. Tegus had higher than baseline mean withdrawal latencies between 0.5 and 1 hour and at 12 hours with morphine at 5 mg/kg and between 1 and 12 hours with morphine at 10 mg/kg. With butorphanol at 5 and 10 mg/kg, tegus maintained withdrawal responses similar to baseline at all assessment points.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that morphine, but not butorphanol, provided antinociception at 5 and 10 mg/kg in tegus as measured by thermal noxious stimulus testing. These data supported the hypothesis that μ-opioid (but not κ-opioid) receptor agonists provide antinociception in reptiles.
Abstract
OBJECTIVE
To evaluate the effects of providing 100% O2, compared with the provision of 21% O2 (equivalent to room air), in mechanically ventilated, sevoflurane-anesthetized green sea turtles (Chelonia mydas).
ANIMALS
Eleven juvenile green sea turtles.
PROCEDURES
In a randomized, blinded, cross-over study (1-week interval between treatments), turtles were anesthetized with propofol (5 mg/kg, IV), orotracheally intubated, mechanically ventilated with 3.5% sevoflurane diluted in 100% O2 or 21% O2 for 90 minutes. Sevoflurane delivery immediately ceased and animals remained under mechanical ventilation with the assigned fraction of inspired oxygen until extubation. Recovery times, cardiorespiratory variables, venous blood gases, and lactate values were evaluated.
RESULTS
Cloacal temperature, heart rate, end-tidal partial pressure of carbon dioxide, and blood gases were unremarkable between treatments. The SpO2 was higher with the provision of 100% O2 than 21% O2 during both anesthesia and recovery (P < .01). Time to bite the bite block was longer in 100% O2 (51 [39–58] minutes) than in 21% O2 (44 [31–53] minutes; P = .03), while time to first muscle movement, attempt to extubate, and extubation were comparable between treatments.
CLINICAL RELEVANCE
Blood oxygenation appears to be lower during sevoflurane anesthesia in room air than in 100% O2, though both fractions of inspired oxygen were able to supply the aerobic metabolism of turtles based on acid-base profiles. In relation to room air, the provision of 100% O2 did not produce meaningful effects on the time to recovery in mechanically ventilated green turtles submitted to sevoflurane anesthesia.
Abstract
Objective—To compare the ability of a sidestream capnograph and a mainstream capnograph to measure end-tidal CO2 (ETCO2) and provide accurate estimates of PaCO2 in mechanically ventilated dogs.
Design—Randomized, double Latin square.
Animals—6 healthy adult dogs.
Procedure—Anesthesia was induced and neuromuscular blockade achieved by IV administration of pancuronium bromide. Mechanical ventilation was used to induce conditions of standard ventilation, hyperventilation, and hypoventilation. While tidal volume was held constant, changes in minute volume ventilation and PaCO2 were made by changing the respiratory rate. Arterial blood gas analysis was performed and ETCO2 measurements were obtained by use of either a mainstream or a sidestream capnographic analyzer.
Results—A linear regression model and bias analysis were used to compare PaCO2 and ETCO2 measurements; ETCO2 measurements obtained by both capnographs correlated well with PaCO2. Compared with PaCO2, mainstream ETCO2 values differed by 3.15 ± 4.89 mm Hg (mean bias ± SD), whereas the bias observed with the sidestream ETCO2 system was significantly higher (5.65 ± 5.57 mm Hg). Regardless of the device used to measure ETCO2, bias increased as PaCO2 exceeded 60 mm Hg.
Conclusions and Clinical Relevance—Although the mainstream capnograph was slightly more accurate, both methods of ETCO2 measurement correlated well with PaCO2 and reflected changes in the ventilatory status. However, ETCO2 values > 45 mm Hg may inaccurately reflect the severity of hypoventilation as PaCO2 may be underestimated during conditions of hypercapnia (PaCO2 > 60 mm Hg). (J Am Vet Med Assoc 2002;221:1582–1585)
Abstract
Objective—To compare the renal and cardiorespiratory effects of IV treatment with lactated Ringer's solution (LRS) or physiologic saline (0.9% NaCl) solution (PSS) in severely decompensated cats with urethral obstruction (UO).
Animals—14 cats (4 cats were used only to establish infusion rates).
Procedures—An occluded urethral catheter was used to induce UO in each cat. After development of severe metabolic acidosis, hyperkalemia, and postrenal azotemia, the obstruction was relieved (0 hours); LRS or PSS (5 cats/group) was administered IV (gradually decreasing rate) beginning 15 minutes before and continuing for 48 hours after UO relief. Ten minutes before urethral catheter placement (baseline), at start of fluid therapy (SFT), and at intervals during fluid administration, various physical and clinicopathologic evaluations were performed.
Results—Metabolic acidosis was detected in the PSS-treated group at SFT and 2 hours after relief of UO and in the LRS-treated group only at SFT The PSS-treated group had significantly lower blood pH and bicarbonate concentrations at 8 through 48 hours and lower base excess values at 2 through 48 hours, compared with the LRS-treated group. Hypocalcemia and hypernatremia were detected in the PSS-treated group at 2 and 12 hours, respectively. Absolute serum potassium and chloride concentrations did not differ significantly between groups at any time point.
Conclusions and Clinical Relevance—Treatment with LRS or PSS appeared to be safe and effective in cats with experimentally induced UO; however, LRS was more efficient in restoring the acid-base and electrolyte balance in severely decompensated cats with UO.
