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1.

Objectives

To document the time for anesthesia induction and recovery using different concentrations of essential oils (EOs) of Cymbopogon flexuosus and Aloysia triphylla in silver catfish (Rhamdia quelen), and to determine whether the mechanism of action of either EO involves the benzodiazepine (BDZ) site of the GABAA receptor.

Study design

Experimental study.

Animals

A total of 144 silver catfish, length 7.5 ± 1.1 cm, weighing 3.95 ± 0.85 g.

Methods

Essential oils were evaluated at concentrations of 25, 150 and 300 μL L?1, and also ethanol alone (seven groups, n = 6 per group). Induction of sedation or anesthesia and recovery were assessed. In a further six groups (n = 6 per group), fish were exposed to both EOs (25, 150 or 300 μL L?1) with diazepam 150 μm, and also diazepam (10 μm) alone. Flumazenil (5 or 10 μm) was added to the recovery water of fish exposed to diazepam (150 μm) or both EOs (150 and 300 μL L?1) (total of 10 groups = 60 fish).

Results

Both EOs induced anesthesia at concentrations of 150 and 300 μL L?1, and sedation at 25 μL L?1. There was no significant difference between EOs for reaching deep anesthesia; there was a significantly longer recovery time for the EO of C. flexuosus. The addition of diazepam (150 μm) resulted in faster induction of anesthesia with both EOs, with no significant change in recovery times. Flumazenil (10 μm) reversed the diazepam-induced anesthesia, but not the anesthesia induced by EOs.

Conclusions and clinical relevance

The EO of C. flexuosus induced effective sedation (25 μL L?1) and anesthesia (150 and 300 μL L?1) without short-term mortality. The modulation of the BDZ site of the GABAA receptor in the anesthetic action mechanism of both EOs was not demonstrated.  相似文献   

2.

Objective

To compare the effects of two balanced anaesthetic protocols (isoflurane–dexmedetomidine versus medetomidine) on sedation, cardiopulmonary function and recovery in horses.

Study design

Prospective, blinded, randomized clinical study.

Animals

Sixty healthy adult warm blood horses undergoing elective surgery.

Methods

Thirty horses each were sedated with dexmedetomidine 3.5 μg kg?1 (group DEX) or medetomidine 7 μg kg?1 (group MED) intravenously. After assessing and supplementing sedation if necessary, anaesthesia was induced with ketamine/diazepam and maintained with isoflurane in oxygen/air and dexmedetomidine 1.75 μg kg?1 hour?1 or medetomidine 3.5 μg kg?1 hour?1. Ringer's lactate (7–10 mL kg?1 hour?1) and dobutamine were administered to maintain normotension. Controlled mechanical ventilation maintained end-tidal expired carbon dioxide pressures at 40–50 mmHg (5.3–6.7 kPa). Heart rate, invasive arterial blood pressure, inspired and expired gas composition and arterial blood gases were measured. Dexmedetomidine 1 μg kg?1 or medetomidine 2 μg kg?1 was administered for timed and scored recovery phase. Data were analysed using two-way repeated-measures analysis of variance and chi-square test. Significance was considered when p  0.05.

Results

In group DEX, significantly more horses (n = 18) did not fulfil the sedation criteria prior to induction and received one or more supplemental doses, whereas in group MED only two horses needed one additional bolus. Median (range) total sedation doses were dexmedetomidine 4 (4–9) μg kg?1 or medetomidine 7 (7–9) μg kg?1. During general anaesthesia, cardiopulmonary parameters did not differ significantly between groups. Recovery scores in group DEX were significantly better than in group MED.

Conclusions and clinical relevance

Horses administered dexmedetomidine required more than 50% of the medetomidine dose to reach equivalent sedation. During isoflurane anaesthesia, cardiopulmonary function was comparable between the two groups. Recovery scores following dexmedetomidine were better compared to medetomidine.  相似文献   

3.

Objective

The evaluation of alfaxalone as a premedication agent and intravenous anaesthetic in pigs.

Study design

Prospective, clinical trial.

Animals

Nine healthy, 6–8-week-old female Landrace pigs weighing 22.2 ± 1.0 kg, undergoing epidural catheter placement.

Methods

All pigs were premedicated with 4 mg kg?1 alfaxalone, 40 μg kg?1 medetomidine and 0.4 mg kg?1 butorphanol administered in the cervical musculature. Sedation was subjectively scored by the same observer from 1 (no sedation) to 10 (profound sedation) prior to induction of anaesthesia with alfaxalone intravenously to effect. All pigs were maintained on alfaxalone infusions with the rate of administration adjusted to maintain appropriate anaesthetic depth. Quality of induction was scored from 1 (poor) to 3 (smooth) and basic cardiorespiratory variables were recorded every 5 minutes during anaesthesia. Results are reported as mean ± standard deviation or median (range) as appropriate.

Results

Sedation scores were 9 (7–10). Inductions were smooth in all pigs and cardiovascular variables remained within normal limits for the duration of anaesthesia. The induction dose of alfaxalone was 0.9 (0.0–2.3) mg kg?1. Three pigs did not require additional alfaxalone after premedication to facilitate intubation.

Conclusions and clinical relevance

Intramuscular alfaxalone in combination with medetomidine and butorphanol produced moderate to deep sedation in pigs. Alfaxalone produced satisfactory induction and maintenance of anaesthesia with minimal cardiovascular side effects. Appropriate monitoring of pigs premedicated with this protocol is required as some pigs may become anaesthetized after intramuscular administration of this combination of drugs.  相似文献   

4.

Objective

To compare the effectiveness of ultrasound- and electrostimulation-guided nerve blocks of the brachial plexus and to determine whether ultrasound guidance is feasible in conscious dogs.

Study design

Blinded, crossover, experimental study.

Animals

Six clinically healthy adult Beagle dogs.

Methods

The nerves of the brachial plexus of the right thoracic limb were blocked under ultrasound guidance (UNB) in conscious dogs and under electrostimulation guidance (ENB) in anesthetized dogs with bupivacaine (0.4 mL kg–1, 0.25%). Saline (0.4 mL kg–1) was injected in control animals. Sensory nerve blockade was evaluated by scoring cutaneous sensation in targeted nerves. Motor nerve blockade was evaluated based on weight bearing, conscious proprioception and withdrawal reflex scores. Times to execute the technique in UNB and ENB were compared using t tests (p < 0.05). Scores for sensory and motor nerve blockades in each treatment were compared with scores before treatment and with control treatment scores using nonparametric repeated-measures two-way analysis of variance. Time to onset and duration of sensory nerve block were assessed using scores for four sensory nerve functions. A successful sensory nerve block was defined by decreases in scores for these functions. Success rates of nerve blocks were compared among treatments using McNemar’s test.

Results

In UNB and ENB, onset times of sensory nerve blocks were 1 hour and 1.5 hours, respectively. Onset times of motor nerve blocks were 0.5 hour in both treatments. In UNB and ENB, durations of sensory nerve block were 3 hours and 0.5 hour, respectively, and durations of motor nerve block were 7.5 hours and 6.5 hours, respectively. Success rates did not differ between the techniques.

Conclusions and clinical relevance

The UNB brachial plexus block had a shorter onset time and longer duration than ENB. UNB can be performed in conscious dogs or those under mild sedation.  相似文献   

5.

Objective

To assess quality of sedation following intramuscular (IM) injection of two doses of alfaxalone in combination with butorphanol in cats.

Study design

Prospective, randomized, ‘blinded’ clinical study.

Animals

A total of 38 cats undergoing diagnostic imaging or noninvasive procedures.

Methods

Cats were allocated randomly to be administered butorphanol 0.2 mg kg?1 combined with alfaxalone 2 mg kg?1 (group AB2) or 5 mg kg?1 (group AB5) IM. If sedation was inadequate, alfaxalone 2 mg kg?1 IM was administered and cats were excluded from further analysis. Temperament [1 (friendly) to 5 (aggressive)], response to injection, sedation score at 2, 6, 8, 15, 20, 30, 40, 50 and 60 minutes, overall sedation quality scored after data collection [1 (excellent) to 4 (inadequate)] and recovery quality were assessed. Heart rate (HR), respiratory rate (fR) and arterial haemoglobin saturation (SpO2) were recorded every 5 minutes. Groups were compared using t tests and Mann–Whitney U tests. Sedation was analysed using two-way anova, and additional alfaxalone using Fisher's exact test (p < 0.05).

Results

Groups were similar for sex, age, body mass and response to injection. Temperament score was lower in group AB2 [2 (1–3)] compared to AB5 [3 (1–5)] (p = 0.006). Group AB5 had better sedation at 6, 8, 20 and 30 minutes and overall sedation quality was better in AB5 [1 (1–3)], compared to AB2 [3 (1–4)] (p = 0.0001). Additional alfaxalone was required for 11 cats in AB2 and two in AB5 (p = 0.005). Recovery quality, HR, fR and SpO2 were similar. Seven cats required oxygen supplementation. Complete recovery times were shorter in AB2 (81.8 ± 24.3 versus 126.6 ± 33.3 minutes; p = 0.009). Twitching was the most common adverse event.

Conclusions and clinical relevance

In combination with butorphanol, IM alfaxalone at 5 mg kg?1 provided better quality sedation than 2 mg kg?1. Monitoring of SpO2 is recommended.  相似文献   

6.

Objective

To investigate whether an intravenous (IV) lidocaine bolus in calves premedicated with xylazine-butorphanol reduces the amount of ketamine required to allow endotracheal intubation.

Study design

Randomized, prospective clinical study.

Animals

In total, 41 calves scheduled for elective umbilical surgery.

Methods

Calves were randomly assigned to one of two groups (L: lidocaine or S: saline). The calves were administered xylazine (0.07 mg kg?1) and butorphanol (0.1 mg kg?1) intramuscularly and 10 minutes later lidocaine (2 mg kg?1; group L) or saline (group S) IV over 1 minute. After 2 minutes, ketamine (2.5 mg kg?1) was injected IV. If the depth of anaesthesia was insufficient for intubation, additional ketamine (1 mg kg?1) was administered every minute until intubation was successful. The amount of ketamine required for intubation, respiratory rate, pulse rate, arterial pressures, the depth of sedation and conditions of endotracheal intubation after induction of anaesthesia were compared between the two groups.

Results

The calves in group L were sedated more deeply than those in group S; however, neither the median (range) amount of ketamine required for intubation, 3.5 (2.5–4.5) mg kg?1 and 3.5 (2.5–3.5) mg kg?1, respectively, nor the induction quality differed significantly between the groups.

Conclusion and clinical relevance

A bolus of lidocaine (2 mg kg?1) administered 10 minutes after xylazine-butorphanol in calves deepened the degree of sedation but did not decrease the requirement of ketamine for endotracheal intubation. No adverse effects were recorded in the physiological variables measured.  相似文献   

7.

Objective

To describe the sedative and physiologic effects of two doses of alfaxalone administered intramuscularly in dogs.

Study design

Randomized, blinded, crossover experimental trial.

Animals

Ten adult mixed-breed dogs.

Methods

Dogs were assigned randomly to be administered one of three intramuscular injections [saline 0.1 mL kg?1 (S), alfaxalone 1 mg kg?1 (A1) or alfaxalone 2 mg kg?1 (A2)] on three occasions. Heart rate (HR), respiratory rate (fR) and sedation score were assessed before injection (T0) and at 5 (T5), 10 (T10), 15 (T15), 20 (T20), 30 (T30), 45 (T45) and 60 (T60) minutes postinjection. Rectal temperature was determined at T0 and T60. Adverse events occurring between the time of injection and T60 were recorded.

Results

Sedation scores were higher in group A2 at T15 and T30 compared with group S. There were no additional differences between groups in sedation score. The A2 group had higher sedation scores at T15, T20 and T30 compared with T0. The A1 group had higher sedation scores at T10 and T30 compared with T0. Temperature was lower in groups A1 and A2 compared with S at T60, but was not clinically significant. There were no differences between or within groups in HR or fR. Adverse effects were observed in both A1 and A2 groups. These included ataxia (17/20), auditory hyperesthesia (5/20), visual disturbance (5/20), pacing (4/20) and tremor (3/20).

Conclusions and clinical relevance

While alfaxalone at 2 mg kg?1 intramuscularly resulted in greater median sedation scores compared with saline, the range was high and adverse effects frequent. Neither protocol alone can be recommended for providing sedation in healthy dogs.  相似文献   

8.
9.
10.

Objective

We investigated the plasma concentrations and cardiovascular effects of intramuscularly (IM) administered medetomidine, administered alone or with three different doses of MK-467.

Study design

Prospective, randomized, open, crossover trial.

Animals

Eight purpose-bred healthy Beagle dogs.

Methods

Each dog was administered four treatments: medetomidine 20 μg kg–1 IM alone or mixed in the same syringe with MK-467 (200 μg kg–1, 400 μg kg–1 or 600 μg kg–1). Instrumentation was performed under standardized anaesthesia. The dogs were allowed to recover before measurement of baseline values. Composite sedation scores, cardiovascular variables, i.e., heart rate (HR), cardiac output (CO), mean arterial and central venous blood pressures (MAP and CVP) and arterial blood gases were recorded at baseline and for 60 minutes after treatment. Drug concentrations in venous plasma were analysed. Generalized linear mixed models for repeated measures with post hoc Bonferroni correction were used with statistical significance level set at α = 0.05.

Results

All treatments initially demonstrated the effects of medetomidine: HR and CO decreased and CVP increased. MAP transiently increased and then significantly decreased from baseline with the two highest MK-467 doses. The cardiovascular effects of medetomidine disappeared more rapidly with MK-467 than with medetomidine alone. With medetomidine alone, sedation scores remained high until the end of the 60 minute follow-up. Maximum concentrations of medetomidine were more rapidly achieved and were higher with MK-467.

Conclusions and clinical relevance

Initial haemodynamic effects of medetomidine were not prevented by MK-467, but these effects were attenuated and their duration shortened by MK-467, independently of dose. Absorption of medetomidine was accelerated by MK-467, when administered concomitantly IM, resulting in faster sedation; addition of MK-467 shortened the sedative effect of medetomidine.  相似文献   

11.

Objective

To evaluate the efficacy, in terms of the amount of rescue analgesia required, and the clinical usefulness of epidural injection of morphine with bupivacaine or levobupivacaine for elective pelvic limb surgery in dogs during a 24-hour perioperative period.

Study design

Prospective, blinded, randomized clinical study.

Animals

A group of 26 dogs weighing 31.7 ± 14.2 (mean ± standard deviation) kg and aged 54 ± 36 months.

Methods

All dogs were premedicated with methadone intravenously (0.2 mg kg–1) and anaesthesia induced with diazepam (0.2 mg kg–1) and propofol intravenously to effect. After induction of anaesthesia, dogs randomly received a lumbosacral epidural injection of morphine 0.1 mg kg–1 with either levobupivacaine 0.5% (1 mg kg–1; group LevoBM) or bupivacaine 0.5% (1 mg kg–1; group BM). Cardiovascular, respiratory and temperature values were recorded during the intra- and postoperative period. A visual analogue scale, subjective pain scale, sedation scale and the short form of the Glasgow pain scale were assessed every 6 hours after epidural injection during 24 hours. The ability to stand and walk, neurological deficits and other side effects were assessed at the same time points. The amount of rescue analgesia (sufentanil intraoperatively and methadone postoperatively) was recorded.

Results

No statistically significant differences were found between groups for any of the recorded data, with the exception of the incidence of spontaneous urination and postoperative rescue analgesia requirement. In group LevoBM four dogs spontaneously urinated at recovery while none of the dogs in group BM did (p = 0.03) and seven dogs of group LevoBM required postoperative rescue analgesia versus none of the dogs in the BM group (p = 0.005).

Conclusions

and clinical relevance Epidural LevoBM is a suitable alternative to BM in healthy dogs during elective pelvic limb surgery. Epidural BM produced more urinary retention but better pain control compared to the same concentration and dose of LevoBM in dogs.  相似文献   

12.
13.

Objective

To assess and compare the sedative and antinociceptive effects of four dosages of dexmedetomidine in donkeys.

Study design

Randomized, controlled, crossover, Latin-square, blinded study.

Animals

Six healthy, castrated, adult, standard donkeys.

Methods

Dexmedetomidine (2, 3, 4 and 5 μg kg?1; D2, D3, D4 and D5), acepromazine (0.1 mg kg?1) and saline were administered intravenously to each donkey and a 1 week interval was allowed between successive trials on each animal. Sedation scores (SS) and head heights above ground (HHAG) were used to assess sedation and mechanical nociceptive threshold (MNT) testing to assess antinociception over 120 minutes post-treatment. Areas under the curve (AUC) for 0–30, 30–60 and 60–120 minutes were computed to compare the effect of treatments.

Results

SS-AUC0–30 values were larger for D4 and D5, and SS-AUC30–60 values were larger for D5 than for saline. All dexmedetomidine treatments produced lower HHAG-AUC0–30 and HHAG-AUC30–60 values, and acepromazine produced lower HHAG AUC60–120 values than did saline. For MNT, D3, D4 and D5 increased AUC0–30 and AUC30–60 values compared with saline and also AUC0–30 values compared with D2 and acepromazine. Smaller MNT-AUC30–60 values were obtained with D2 than with D4 and D5, with D3 than with D5, and with acepromazine than with D4 and D5.

Conclusions and clinical relevance

Dexmedetomidine induced sedation and dosage-dependent mechanical antinociception. Larger dexmedetomidine dose rates were required to induce antinociception than sedation. Furthermore, the antinociception induced by dexmedetomidine was of shorter duration than its sedation. For minor painful procedures on standing donkeys, D5 may be clinically useful to provide sedation and analgesia.  相似文献   

14.

Objective

To study the effect of heterothermia on anaesthetic drug requirements in semi-free ranging Arabian oryx and to assess the temperature quotient (Q10) of oxygen consumption.

Study design

Prospective observational study and controlled metabolic experiment.

Animals

Sixty-eight anaesthetic events in 59 Arabian oryx from Mahazat As-Sayd protected area, Saudi Arabia

Methods

Anaesthesia was induced by remote injection of 25 mg ketamine, 10 mg midazolam and 0.5 mg medetomidine with a variable amount of etorphine based on a target dosage of 20 μg kg–1 and subjective assessment of body mass. Animals not recumbent within 15 minutes or insufficiently anaesthetized were physically restrained and administered supplementary etorphine intravenously depending on the anaesthetic depth. Body temperature (Tb) was measured rectally immediately upon handling of each animal. From six anaesthetized oryx, expiratory gasses for oxygen analysis and metabolic rate calculation were collected at two Tbs; before and after submersion in ice water for approximately 30 minutes.

Results

Forty-two animals (62%) became recumbent with the initial dose, with a mean induction time (± standard deviation) of 9 ± 2 minutes. The remaining animals could be handled but needed 0.3 ± 0.1 mg etorphine intravenously to reach the desired level of anaesthesia. There was a significant positive correlation between Tb and effective etorphine dosage (R2 = 0.48, p < 0.0001). Average Tb of the six animals in which metabolic rate was measured decreased from 40.0 ± 0.5°C immediately after induction to 35.5 ± 0.5°C after cooling. This reduction was associated with a reduction in oxygen uptake from 3.11 ± 0.33 to 2.22 ± 0.29 mL O2 minute–1 kg–1, reflected in Q10 of 2.17 ± 0.14.

Conclusions and clinical relevance

Tb significantly affects anaesthetic requirements in Arabian oryx and should be considered when selecting dosages for anaesthetic induction for species showing diurnal heterothermy.  相似文献   

15.

Objective

To determine if concentrations of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) are increased in dogs with cardiac tamponade and if there is a significant increase in plasma NT-proBNP after pericardiocentesis.

Animals

Ten client-owned dogs with spontaneous cardiac tamponade.

Methods

Prospective clinical study. Cardiac tamponade was suspected from physical examination and confirmed with echocardiography. Blood was collected and plasma NT-proBNP concentrations were measured before and 30–60 min following pericardiocentesis and resolution of cardiac tamponade. Within-subject changes in plasma NT-proBNP were compared by the Wilcoxon signed-rank test.

Results

The plasma NT-proBNP concentrations measured within the reference interval in seven of 10 dogs before pericardiocentesis and in six of 10 dogs following pericardiocentesis. Following pericardiocentesis, there was a statistically significant increase in median NT-proBNP concentration (733 pmol/L, range 250–3,297) compared with the values measured before (643 pmol/L, range 250–3,210, P = 0.004). The NT-proBNP concentration increased in 90% of the dogs following pericardiocentesis.

Conclusions

An upper reference limit of 900 pmol/L for plasma NT-proBNP is insensitive for the diagnosis of pericardial effusion and cardiac tamponade in dogs. Plasma NT-proBNP concentration commonly increases following pericardiocentesis, perhaps related to improved ventricular filling and stretch.  相似文献   

16.

Objective

To evaluate the ability of a noninvasive cardiac output monitoring system with electrical velocimetry (EV) for predicting fluid responsiveness in dogs undergoing cardiac surgery.

Study design

Prospective experimental trial.

Animals

A total of 30 adult Beagle dogs.

Methods

Stroke volume (SV), stroke volume variation (SVV) and cardiac index were measured using the EV device in sevoflurane-anaesthetized, mechanically ventilated dogs undergoing thoracotomies for experimental creation of right ventricular failure. The dogs were considered fluid responsive if stroke volume (SVI; indexed to body weight), measured using pulmonary artery thermodilution, increased by 10% or more after volume loading (10 mL kg–1). Relationships of SVV, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) with SVI were analysed to estimate fluid responsiveness.

Results

Better prediction of fluid responsiveness, with a significant area under the receiver operating characteristic curve, was observed for SVV (0.85 ± 0.07; p = 0.0016) in comparison with CVP (0.65 ± 0.11; p = 0.17) or PAOP (0.60 ± 0.12; p = 0.35), with a cut-off value of 13.5% (84% specificity and 73% sensitivity).

Conclusions and clinical relevance

SVV derived from EV is useful for identification of dogs that are likely to respond to fluids, providing valuable information on volume status under cardiothoracic anaesthesia.  相似文献   

17.

Objective

To evaluate the analgesic efficacy of Yamamoto New Scalp Acupuncture (YNSA) as an adjuvant for postoperative pain management in cats.

Study design

Prospective, randomized, blinded, clinical study.

Animals

Twenty cats aged (mean ± standard deviation) 25 ± 9 months and weighing 2.7 ± 0.6 kg undergoing ovariohysterectomy.

Methods

The cats were sedated with intramuscular (IM) ketamine (5 mg kg?1), midazolam (0.5 mg kg?1) and tramadol (2 mg kg?1). The cats were randomly distributed before induction of anesthesia into two groups of 10 cats each: group YNSA, in which bilateral basic D points were stimulated with a dry needle from 20 minutes prior to anesthetic induction to the end of the surgery; group Control, in which no acupuncture was applied. Postoperative analgesia was assessed at 1, 2, 4, 8, 12, 18 and 24 hours postextubation using an Interactive Visual Analog Scale and Universidade Estadual Paulista-Botucatu Multidimensional Composite Pain Scale (UNESP-Botucatu MCPS). Rescue analgesia was provided with IM tramadol (2 mg kg?1), and the pain scores were reassessed 30 minutes after rescue intervention. If the analgesia remained insufficient, meloxicam (0.2 mg kg?1 as a single dose) was administered IM. Data were analyzed using Student t-test, Fisher exact test, Mann–Whitney U test and Friedman test (p < 0.05).

Results

Significantly lower pain scores were observed in YNSA when compared with Control at 1–4 hours based on the UNESP-Botucatu MCPS scores. Although significant differences were not identified between groups requiring rescue analgesia, additional postoperative analgesia was administered to four of 10 cats in Control and no cats in YNSA.

Conclusion and clinical relevance

Perioperative YNSA resulted in decreased pain scores and a reduction in postoperative requirement for rescue analgesia in cats. This method should be considered a viable option as an adjuvant analgesic therapy for cats undergoing ovariohysterectomy.  相似文献   

18.

Objective

To compare dexmedetomidine–midazolam with alfaxalone–midazolam for sedation in leopard geckos (Eublepharis macularius).

Study design

Prospective, randomized, blinded, complete crossover study.

Animals

Nine healthy adult leopard geckos.

Methods

Geckos were administered a combination of dexmedetomidine (0.1 mg kg?1) and midazolam (1.0 mg kg?1; treatment D–M) or alfaxalone (15 mg kg?1) and midazolam (1.0 mg kg?1; treatment A–M) subcutaneously craniodorsal to a thoracic limb. Heart rate (HR), respiratory rate (fR), righting reflex, palpebral reflex, superficial and deep pain reflexes, jaw tone and escape response were assessed every 5 minutes until reversal. Conditions for intubation and response to needle prick were evaluated. Antagonist drugs [flumazenil (0.05 mg kg?1) ± atipamezole (1.0 mg kg?1)] were administered subcutaneously, craniodorsal to the contralateral thoracic limb, 45 minutes after initial injection, and animals were monitored until recovery.

Results

HR, but not fR, decreased significantly over time in both treatments. HR was significantly lower than baseline at all time points in D–M and for all but the 5 and 10 minute time points in A–M. HR was significantly higher in A–M at all time points after drug administration when compared with D–M. Sedation scores between protocols were similar for most time points. All animals in A–M lost righting reflex compared with seven out of nine (78%) geckos in D–M. Geckos in A–M lost righting reflex for significantly longer time. Mean ± standard deviation time to recovery after antagonist administration was 6.1 ± 2.2 minutes for D–M and 56 ± 29 minutes for A–M, and these times were significantly different.

Conclusions and clinical relevance

Combination D–M or A–M provided sedation of a level expected to allow physical examinations and venipuncture in leopard geckos. A–M provided a faster onset of sedation compared with D–M. Recovery was significantly faster following antagonist reversal of D–M, compared with A–M.  相似文献   

19.

Objective

To characterize the pharmacokinetics of dexmedetomidine when administered as a short intravenous (IV) infusion to isoflurane-anesthetized rabbits.

Study design

Experimental study.

Animals

A total of six healthy adult female New Zealand White rabbits.

Methods

Rabbits were anesthetized with isoflurane in oxygen. Following determination of isoflurane minimum alveolar concentration (MAC), the anesthetic dose was reduced to 0.7 × MAC, and dexmedetomidine hydrochloride (20 μg kg?1) was infused IV over 5 minutes. Arterial blood samples were obtained immediately before and at 1, 2, 5, 6, 7, 10, 15, 30, 60, 90, 120, 240 and 360 minutes following termination of the infusion. Samples were transferred into tubes containing ethylenediaminetetraacetic acid and centrifuged immediately. The plasma was harvested and stored at –80 °C until analyzed. Concentrations of dexmedetomidine in plasma were determined by liquid chromatography mass spectrometry. Compartment models were fitted to the time and concentration data using nonlinear regression.

Results

A three-compartment model best fit the data set. Median volume of distribution at steady state and terminal half-life were 3169 mL kg?1 (range, 2182–3859 mL kg?1) and 80 minutes (range, 72–88 minutes), respectively.

Conclusions and clinical relevance

The pharmacokinetics of dexmedetomidine in isoflurane-anesthetized, healthy, New Zealand White rabbits were characterized in this study. Data from this study can be used to determine dosing regimens for dexmedetomidine in isoflurane-anesthetized rabbits.  相似文献   

20.

Objective

To determine the effects of brimonidine tartrate ophthalmic solution on sedation, heart rate (HR), respiratory frequency (fR), rectal temperature (RT) and noninvasive mean arterial pressure (MAP) in healthy cats.

Study design

Randomized, blinded crossover study, with 1 week washout between treatments.

Animals

Six healthy purpose-bred cats.

Methods

Brimonidine tartrate ophthalmic solution 0.1% (one or two drops; 58.6 ± 3.3 μg per drop) or a control solution (artificial tear solution) was administered to six healthy cats. Behavioural observations and measurements of HR, fR, RT and MAP were recorded before and at 30, 60, 90, 120, 180, 240, 300 and 360 minutes after topical administration. Behavioural scores were analysed using Friedman’s test for repeated measures to evaluate the time effect in each treatment and treatment effect at each time point. Physiological variables (HR, fR, RT and MAP) were analysed using two-way analysis of variance for repeated measures to evaluate the time and treatment effects. The level of significance was set at p < 0.05.

Results

Dose-dependent behavioural and physiological responses were noted. A dose of two drops of brimonidine resulted in sedation in the cats and decreased HR and MAP. Significant sedative effects occurred between 30 and 120 minutes and for physiological responses up to 360 minutes. The most frequent adverse reaction was vomiting, occurring within 40 minutes in all six cats administered two drops and five of the six cats administered one drop of brimonidine.

Conclusions and clinical relevance

The results demonstrated that ocular administration of brimonidine 0.1% ophthalmic solution induced sedation in cats and some cardiovascular effects usually associated with α2-adrenoceptor agonists. Further studies should be performed to determine clinical applications for this agent in cats.  相似文献   

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