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1.

Objective

To evaluate whether intratesticular and incisional ropivacaine infiltration produces sufficient intra- and postoperative analgesia for castrating dogs under sedation.

Study design

Randomized, blinded, controlled clinical study.

Animals

Twenty-three healthy dogs weighing 5.8–35.6 kg admitted for castration.

Methods

Dogs were sedated with medetomidine (0.01 mg kg?1), butorphanol (0.2 mg kg?1) and midazolam (0.2 mg kg?1) intramuscularly, and were randomly assigned to group R, 0.2–0.4 mL kg?1 of ropivacaine 0.5%, or group S, an equivalent volume of saline injected intratesticularly and along the incision line. If persistent motion was observed during surgery, sedation was considered to be insufficient and general anaesthesia was induced. Carprofen 2.2 mg kg?1 was administered postoperatively. Pain was evaluated in all dogs before sedation and postoperatively following atipamezole administration at 1, 2, 4, 8 and 24 hours using an interactive visual analogue scale (IVAS; 0–100), the Glasgow composite pain scale-short form (CMPS-SF; 0–24), and a mechanical algometer. Methadone 0.3 mg kg?1 was administered intravenously to dogs if IVAS >30 or CMPS-SF >4.

Results

There was no significant difference between groups for the number of dogs administered general anaesthesia. The time from the beginning of surgery to induction of general anaesthesia was significantly shorter [median (range)] in group S [6 (3–25) minutes] than in group R [56 (36–76) minutes]. At 8 hours IVAS was significantly higher in group S (14 ± 10) than in group R (6 ± 4).

Conclusions and clinical relevance

Intratesticular and incisional ropivacaine infiltration delayed the time to anaesthesia induction, and provided analgesia after castration performed under deep sedation in dogs. Intratesticular local anaesthesia can be an important part of the anaesthetic plan for castration.  相似文献   

2.

Objective

The aim of this study was to determine whether lumbosacral epidural administration of magnesium sulphate added to ropivacaine prolongs and improves perioperative analgesia, without adverse effects on motor block duration or hind limb neurological function, in dogs undergoing hip arthroplasty.

Study design

Investigator-blind, controlled, randomized, prospective clinical trial.

Animals

A group of 20 client-owned dogs undergoing hip arthroplasty were allocated randomly to either group C (control, 1 mg kg?1epidural ropivacaine) or group M (magnesium, epidural injection of 1 mg kg?1 ropivacaine and 2 mg kg?1magnesium sulphate).

Methods

All dogs were premedicated with intramuscular acepromazine. General anaesthesia was induced with propofol and maintained with isoflurane in oxygen. Intraoperatively, nociception was assessed based on changes in heart rate, respiratory rate and mean arterial pressure above baseline values. Postoperatively, pain was evaluated with a Sammarco pain score, a Glasgow pain scale and a visual analogue scale (VAS). Tarlov’s scale was used to quantify motor block. All dogs were evaluated at recovery and then 1, 2, 3, 4, 5 and 24 hours after that. Rescue analgesia was provided during surgery with fentanyl and, postoperatively, with buprenorphine. Groups were compared using one-way repeated-measure analysis of variance followed by the Holm–Sidak method for multiple comparison or nonparametric tests when appropriate.

Results

The two treatment groups did not differ (p > 0.05) with respect to intraoperative physiological variables, rescue analgesia, postoperative pain scores (Sammarco q = 1.00; Glasgow q = 3.10; VAS q = 0.50) and duration of the motor block (Tarlov’s q = 2.40).

Conclusions and clinical relevance

The addition of epidural magnesium to ropivacaine did not improve or prolong the analgesia provided by ropivacaine alone. Further studies are needed to determine whether an epidural magnesium dose of >2 mg kg?1 would exert better analgesia, without causing adverse effects, in dogs undergoing orthopaedic surgery.  相似文献   

3.

Objective

To investigate the pharmacokinetics of buprenorphine and its main active metabolite, norbuprenorphine, after administration of an intravenous loading dose followed by constant rate infusion (CRI) in dogs.

Study design

Prospective, clinical study.

Animals

A total of seven healthy dogs undergoing elective ovariectomy.

Methods

Buprenorphine was administered as a loading dose (intravenous bolus of 15 μg kg?1) followed by CRI (2.5 μg kg?1 hour?1 for 6 hours). Moreover, intraoperative analgesia was supplemented by an intramuscular carprofen (4 mg kg?1) injection, administered prior to surgery, and by lidocaine, administrated through subcutaneous infiltration and through a splash on the ovarian vascular pedicle during surgery. Pain and sedation were scored for all animals throughout the 24-hour study period and rescue analgesia was administered when a visual analogue scale score was > 40 mm. Blood samples were collected from a jugular catheter at regular intervals, and plasma concentrations of buprenorphine and norbuprenorphine were determined by a validated liquid chromatography–tandem mass spectrometry method.

Results

Buprenorphine showed a two-compartment kinetic profile. Maximum concentration was 23.92 ± 8.64 ng mL?1 at 1 minute (maximum time); elimination half-life was 41.87 ± 17.35 minutes; area under the curve was 486.68 ± 125.66 minutes ng?1 mL?1; clearance was 33.61 ± 13.01 mL minute?1 kg?1, and volume of distribution at steady state was 1.77 ± 0.50 L kg?1. In no case was rescue analgesia required. Norbuprenorphine resulted below the lower limit of quantification in almost all samples.

Conclusions and clinical relevance

The results suggest that a buprenorphine CRI can be a useful tool for providing analgesia in postoperative patients, considering its minor side effects and the advantages of a CRI compared to frequent boluses. The negligible contribution of norbuprenorphine to the therapeutic effect was confirmed.  相似文献   

4.

Objective

To test the efficacy of intraoperative intrafragmentary administration of bupivacaine (haematoma block) in controlling postoperative pain in dogs undergoing osteosynthesis of long-bone isolated diaphyseal fractures.

Study design

Randomized, ‘blinded’, placebo-controlled, prospective study.

Animals

A total of 23 client-owned dogs with isolated long-bone fractures.

Methods

Dogs were allocated randomly to two groups: bupivacaine group (B) or placebo group (P). Group B dogs (n = 11) were administered an intraoperative intrafragmentary injection of 0.5% bupivacaine (1.1 mg kg–1) just before fracture fixation, whereas group P dogs (n = 12) were administered normal saline. Postoperative pain evaluations using the University of Melbourne Pain Scale (UMPS) and algometer were performed upon arrival to the recovery room and 1, 2, 4, 6, 8, 20 and 32 hours later. Algometer measurements were performed on: the incision site, a healthy region near the fracture line and the contralateral healthy limb. When the pain score exceeded 14 points in the UMPS, rescue analgesia was administered. The time-standardised area under the curve (AUCst) was used to compare UMPS scores and mechanical pain thresholds between the two groups.

Results

None of the group B dogs required rescue analgesia, whereas eight of the 12 group P dogs did (p = 0.001). The pain threshold AUCst at the incision line was higher in group B [16.3 (2.9–41.6) N] than in group P [5.6 (2.5–17.4) N] (p = 0.029). The mean UMPS score AUCst was lower in group B (3.7 ± 1.8) than in group P (9.4 ± 4.6) (p = 0.016). In a small number of animals of both groups that were evaluated radiologically, adequate bone healing was noted.

Conclusions and clinical relevance

An intraoperative bupivacaine haematoma block is a simple, quick and effective method that can be used to aid in postoperative pain control in dogs submitted to long-bone osteosynthesis.  相似文献   

5.

Objective

To compare the effects of intravenous (IV) medetomidine-morphine and medetomidine-methadone on preoperative sedation, isoflurane requirements and postoperative analgesia in dogs undergoing laparoscopic surgery.

Study design

Randomized, crossover trial.

Animals

Twelve adult Beagle dogs weighing 15.1 ± 4.1 kg.

Methods

Dogs were administered medetomidine (2.5 μg kg?1) IV 5 minutes before either methadone (MET) or morphine (MOR) (0.3 mg kg?1) IV. Anaesthesia was induced with propofol, maintained with isoflurane in oxygen, and depth was clinically assessed and adjusted by an anaesthetist blinded to the treatment. Animals underwent laparoscopic abdominal biopsies. Sedation and nausea scores, pulse rate (PR), respiratory rate (fR), noninvasive systolic arterial blood pressure (SAP), rectal temperature (RT) and pain scores were recorded before drug administration, 5 minutes after medetomidine injection and 10 minutes after opioid administration. Propofol dose, PR, fR, SAP, oesophageal temperature (TOES), end-tidal carbon dioxide and end-tidal isoflurane concentration (Fe′Iso) were recorded intraoperatively. Pain scores, PR, fR, SAP and RT were recorded 10 minutes after extubation, every hour for 6 hours, then at 8, 18 and 24 hours. The experiment was repeated with the other drug 1 month later.

Results

Nine dogs completed the study. After opioid administration and intraoperatively, PR, but not SAP, was significantly lower in MET. Fe′Iso was significantly lower in MET. Temperature decreased in both treatments. Pain scores were significantly higher in MOR at 3 hours after extubation, but not at other time points. Two dogs required rescue analgesia; one with both treatments and one in MOR.

Conclusion and clinical relevance

At the dose used, sedation produced by both drugs when combined with medetomidine was equivalent, while volatile anaesthetic requirements and PR perioperatively were lower with methadone. Postoperative analgesia was deemed to be adequate for laparoscopy with either protocol, although methadone provided better analgesia 3 hours after surgery.  相似文献   

6.

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   

7.

Objective

To evaluate analgesic efficacies of morphine and butorphanol in lame broiler chickens.

Study design

Double blind, randomized, controlled experimental study.

Animals

In study 1, 36 lame and 36 sound chickens. In study 2, 48 lame and 48 sound chickens.

Methods

Sound and lame chickens were gait scored and randomly assigned into four groups: sound-drug, sound-placebo, lame-drug, and lame-placebo in study 1. In study 2, an additional lame and sound handling control group was included. Chickens in drug groups were injected with either morphine or butorphanol 2 mg kg?1 intravenously. Chickens in placebo groups were injected with an equal volume of normal saline. All birds underwent an obstacle course (OC) and latency-to-lie (LTL) test before injection and at 30 minutes and 2 hours after injection, to assess their walking ability and their standing ability. The time taken to finish the OC and the standing time in the LTL test were recorded. Friedman tests with Dunn’s correction were used to identify significant differences.

Results

Lame chickens finished the OC faster (mean ± standard deviation 36 ± 8 c.f. 69 ± 18 seconds) after the injection of butorphanol. Morphine caused sedation with an increase in time taken to finish the OC, even in sound chickens. In the lame handling control and placebo groups the OC times increased and the LTL times decreased with each observation.

Conclusion

Intravenous butorphanol (2 mg kg?1) may be analgesic in chickens for up to 2 hours. Morphine caused sedation.  相似文献   

8.

Objective

The aim of this study was to investigate whether an increased frequency of gastro-oesophageal reflux (GOR) is more common in large-sized, deep-chested dogs undergoing spinal surgery in sternal recumbency than in small-sized, barrelchested dogs.

Study design

Prospective, cohort study.

Animals

Nineteen small-sized, barrel-chested dogs (group B) and 26 large-sized, deep-chested dogs (group D).

Methods

All animals were premedicated with intramuscular (IM) acepromazine (0.05 mg kg?1) and pethidine (3 mg kg?1) IM. Anaesthesia was induced with intravenous sodium thiopental and maintained with halothane in oxygen. Lower oesophageal pH was monitored continuously after induction of anaesthesia. Gastro-oesophageal reflux was considered to have occurred whenever pH values > 7.5 or < 4 were recorded. If GOR was detected during anaesthesia, measures were taken to avoid aspiration of gastric contents into the lungs and to prevent the development of oesophagitis/oesophageal stricture.

Results

The frequency of GOR during anaesthesia was significantly higher in group D (6/26 dogs; 23.07%) than in group B (0/19 dogs; 0%) (p = 0.032). Signs indicative of aspiration pneumonia, oesophagitis or oesophageal stricture were not reported in any of the GOR cases.

Conclusions and clinical relevance

In large-sized, deep-chested dogs undergoing spinal surgery in sternal recumbency, it would seem prudent to consider measures aimed at preventing GOR and its potentially devastating consequences (oesophagitis/oesophageal stricture, aspiration pneumonia).  相似文献   

9.

Objective

To investigate the sedative effects in dogs of tiletamine–zolazepam–acepromazine (TZA) or ketamine–flunitrazepam (KF) administered orally and to evaluate the effectiveness of encapsulated TZA for capturing free-roaming dogs.

Study design

Experimental study followed by a field trial.

Animals

Six research dogs and 27 free-roaming dogs.

Methods

In a pilot study, six research dogs were administered liquid TZA (20 mg kg?1 tiletamine–zolazepam and 2 mg kg?1 acepromazine) or liquid KF (50 mg kg?1 ketamine and 2 mg kg?1 flunitrazepam) orally: treatment 1, forcefully squirting liquid medication into the mouth; treatment 2, encapsulating liquid medication for administration in canned food; treatment 3, administering liquid medication mixed with gravy. Sedation was scored. A follow-up field trial attempted capture of 27 free-roaming dogs.

Results

In the pilot study, the median time (range) to lateral recumbency (% dogs) after TZA administration was: treatment 1, 47.5 (35–80) minutes (67%); treatment 2, 30 (15–65) minutes (83%); and treatment 3, 75 (45–110) minutes (100%). No dogs in KF treatment 2 or 3 achieved lateral recumbency. Based on these results, 20 free-roaming dogs were offered encapsulated TZA in canned food: TZ (20 mg kg?1) and acepromazine (2 mg kg?1). Of these, no further drugs to four dogs (one dog captured), 10 dogs were administered a second dose within 30 minutes (five dogs captured) and six dogs were administered TZ (5 mg kg?1) and xylazine (1.1–2.2 mg kg?1) intramuscularly by blow dart (six dogs captured). Seven dogs were initially offered twice the TZA dose (five dogs captured). In total, 63% free-roaming dogs were captured after administration of encapsulated TZA in canned food.

Conclusions and clinical relevance

Oral administration of encapsulated TZA in canned dog food can aid in the capture of free-roaming dogs, but additional drugs may be required. The sedation onset time and medication palatability influenced the capture rate.  相似文献   

10.

Objectives

Neostigmine is routinely used to reverse non-depolarizing neuromuscular block. Given its indirect mechanism, a plateau may exist whereby increasing doses of neostigmine do not result in clinical benefit. This study was designed to measure the speed of reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs after the administration of three doses of neostigmine as used in clinical practice.

Study design

Prospective, crossover, randomized study.

Animals

Seven adult, mixed-breed dogs with a mean ± standard deviation (SD) age of 2.0 ± 0.8 years and weight of 19.1 ± 9.1 kg.

Methods

Dogs were anesthetized on three occasions with isoflurane and administered vecuronium (0.1 mg kg–1) intravenously (IV). The train-of-four (TOF) ratio was measured on the pelvic limb with acceleromyography. When the second twitch of the TOF had returned spontaneously, atropine (0.03 mg kg–1) and neostigmine (0.02, 0.04 or 0.07 mg kg–1) were administered IV. Time to reach a TOF ratio of ≥0.9 after neostigmine administration was recorded.

Results

Increasing the dose of neostigmine from 0.02 mg kg–1 to 0.04 mg kg–1 and 0.07 mg kg–1 resulted in significant reductions in mean ± SD reversal times (10.5 ± 2.3, 7.4 ± 1.1 and 5.4 ± 0.5 minutes, respectively) (p < 0.0001) and smaller coefficients of variation (22%, 15% and 10%, respectively).

Conclusions and clinical relevance

Increasing the dose of neostigmine from 0.02 mg kg–1 to 0.04 mg kg–1 and 0.07 mg kg–1 produced faster and less variable reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs. No ceiling effect was observed at this dose range.  相似文献   

11.

Objective

To evaluate motor and sensory blockade of combining dexmedetomidine with ropivacaine, administered perineurally or systemically, for femoral and sciatic nerve blocks in conscious dogs.

Study design

Randomized, controlled, experimental study.

Animals

Seven healthy Beagle dogs, aged 3.3 ± 0.1 years and weighing 11.0 ± 2.4 kg.

Methods

Dogs were anesthetized with isoflurane on three separate occasions for unilateral femoral and sciatic nerve blocks and were administered the following treatments in random order: perineural ropivacaine 0.75% (0.1 mL kg–1) on each nerve and intramuscular (IM) saline (0.2 mL kg–1) (GCON); perineural dexmedetomidine (1 μg mL–1) and ropivacaine 0.75% (0.1 mL kg–1) on each nerve and IM saline (0.2 mL kg–1) (GDPN); and perineural ropivacaine 0.75% (0.1 mL kg–1) on each nerve and IM dexmedetomidine (1 μg mL–1, 0.2 mL kg–1) (GDIM). Nerve blocks were guided by ultrasound and electrical stimulation and dogs were allowed to recover from general anesthesia. Sensory blockade was evaluated by response to clamp pressure on the skin innervated by the saphenous/ femoral, common fibular and tibial nerves. Motor blockade was evaluated by observing the ability to walk and proprioception. Sensory and motor blockade were evaluated until their full recovery.

Results

No significant differences in onset time to motor and sensory blockade were observed among treatments. Duration of motor blockade was not significantly different among treatments; however, duration of tibial sensory blockade was longer in the GDPN than in the GDIM treatment.

Conclusions and clinical relevance

Although a longer duration of sensory blockade was observed with perineural dexmedetomidine, a significant increase compared with the control group was not established. Other concentrations should be investigated to verify if dexmedetomidine is a useful adjuvant to local anesthetics in peripheral nerve blocks in dogs.  相似文献   

12.

Objective

To evaluate the onset and duration of hematological changes and the use of Doppler ultrasound (spleen) in dogs sedated with acepromazine or xylazine.

Study design

Clinical study.

Animals

A total of 24 mixed breed dogs aged 1–4 years and weighing 15–25 kg.

Methods

Dogs were randomly distributed into two groups: acepromazine group (AG) which were administered acepromazine (0.05 mg kg?1) intramuscularly and xylazine group (XG) administered xylazine (0.5 mg kg?1) intramuscularly. Sonographic evaluations (morphologic and hemodynamic splenic vascularization) and hematologic tests were performed before drug administration (baseline) and 5, 15, 30, 60, 120, 240, 360, 480 and 720 minutes after drug administration.

Results

A significant reduction occurred in erythrogram variables in AG at 15–720 minutes corresponding with a significant enlargement of the spleen. In XG, a significant reduction was observed in the erythrogram variables at 30–60 minutes without a significant enlargement of the spleen. Hilar diameter did not change over time in either group. Flow alterations were found only in the splenic artery in AG, with a decreased final diastolic velocity observed at 60–120 minutes.

Conclusions

Administration of acepromazine resulted in decreased red blood cell count, hemoglobin, packed cell volume and an increased diameter of the spleen. Xylazine administration resulted in similar hematologic changes but of smaller magnitude and duration and without splenic changes. The absence of significant changes in the Doppler flow parameters of the splenic artery and vein and the hilar diameter suggests that the splenomegaly that was observed in AG was not due to splenic vasodilation. No splenic sequestration occurred after xylazine administration.

Clinical relevance

The results indicate that acepromazine decreases the erythrocyte concentrations by splenic erythrocyte sequestration and concomitant splenomegaly. Xylazine can cause slight hematologic changes, but without splenic changes.  相似文献   

13.

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   

14.

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   

15.

Objective

To characterize the cardiovascular effects of dexmedetomidine, with or without MK-467, following intravenous (IV) administration in cats.

Study design

Prospective Latin square experimental study.

Animals

Six healthy adult purpose-bred cats.

Methods

Cats were anesthetized with desflurane in oxygen for instrumentation with a carotid artery catheter and a thermodilution catheter in the pulmonary artery. One hour after discontinuation of desflurane, cats were administered dexmedetomidine (25 μg kg–1), MK-467 (600 μg kg–1), or dexmedetomidine (25 μg kg–1) and MK-467 (600 μg kg–1). All treatments were administered IV as a bolus. Cardiovascular variables were measured prior to drug administration and for 8 hours thereafter. Only data from the dexmedetomidine and dexmedetomidine–MK-467 treatments were analyzed.

Results

Dexmedetomidine produced significant decreases in heart rate, cardiac index and right ventricular stroke work index, and significant increases in arterial blood pressure, central venous pressure, pulmonary artery pressure and systemic vascular resistance index. Dexmedetomidine combined with MK-467 resulted in significant but transient decrease in blood pressure and right ventricular stroke work index.

Conclusion and clinical relevance

Following IV co-administration, MK-467 effectively attenuated dexmedetomidine-induced cardiovascular effects in cats. The drug combination resulted in transient reduction in arterial blood pressure, without causing hypotension.  相似文献   

16.

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   

17.

Objectives

To compare propofol and alfaxalone, with or without midazolam, for induction of anesthesia in fentanyl-sedated dogs, and to assess recovery from total intravenous anesthesia (TIVA).

Study design

Prospective, incomplete, Latin-square study.

Animals

Ten dogs weighing 24.5 ± 3.1 kg (mean ± standard deviation).

Methods

Dogs were randomly assigned to four treatments: treatment P-M, propofol (1 mg kg?1) and midazolam (0.3 mg kg?1); treatment P-S, propofol and saline; treatment A-M, alfaxalone (0.5 mg kg?1) and midazolam; treatment A-S, alfaxalone and saline, administered intravenously (IV) 10 minutes after fentanyl (7 μg kg?1) IV. Additional propofol or alfaxalone were administered as necessary for endotracheal intubation. TIVA was maintained for 35–55 minutes by infusions of propofol or alfaxalone. Scores were assigned for quality of sedation, induction, extubation and recovery. The drug doses required for intubation and TIVA, times from sedation to end of TIVA, end anesthesia to extubation and to standing were recorded. Analysis included a general linear mixed model with post hoc analysis (p < 0.05).

Results

Significant differences were detected in the quality of induction, better in A-M than A-S and P-S, and in P-M than P-S; in total intubation dose, lower in P-M (1.5 mg kg?1) than P-S (2.1 mg kg?1), and A-M (0.62 mg kg?1) than A-S (0.98 mg kg?1); and lower TIVA rate in P-M (268 μg kg?1 minute?1) than P-S (310 μg kg?1 minute?1). TIVA rate was similar in A-M and A-S (83 and 87 μg kg?1 minute?1, respectively). Time to standing was longer after alfaxalone than propofol, but was not influenced by midazolam.

Conclusions and clinical relevance

Addition of midazolam reduced the induction doses of propofol and alfaxalone and improved the quality of induction in fentanyl-sedated dogs. The dose rate of propofol for TIVA was decreased.  相似文献   

18.

Objective

To describe ultrasound-visualized anatomy and the spread characteristics of a dye injected in the thoracic paravertebral (TPV) space under ultrasound guidance.

Study design

Anatomic cadaver study.

Animals

Seven dog cadavers.

Methods

One cadaver was used to observe, identify, and describe the relevant TPV anatomy. In the remaining six, the left fifth TPV space was randomly assigned to be injected with either a low volume (LV; 0.05 mL kg?1) or high volume (HV; 0.15 mL kg?1) of dye. Subsequently, the contralateral side was injected with the alternative volume. Anatomic dissections were conducted to determine the incidence of complete spinal nerve staining (>1 cm circumferential coverage), number of contiguous spinal nerves dyed and the absence or presence of solution in particular locations.

Results

The ultrasound-visualized anatomy of the TPV space was defined as the intercostal space abaxial to the vertebral body, delimited by the parietal pleura ventrally and the internal intercostal membrane dorsally. The endothoracic fascia divides the paravertebral space into dorsal and ventral compartments. The target nerve was completely dyed in five of six and six of six injections in the LV and HV conditions, respectively. In one LV injection, the nerve was partially dyed. No multisegmental spread affecting contiguous spinal nerves was found in either treatment. Multisegmental spread was found in the ventral compartment of the TPV space, affecting the sympathetic trunk on 3 (0–3) and 3.5 (1–6) vertebral spinal levels in the LV and HV conditions, respectively, but differences between volumes were not significant. No intrapleural, ventral mediastinal or epidural migration was observed.

Conclusions and clinical relevance

Ultrasound-guided TPV block is a potentially reliable technique. The LV appeared sufficient to dye a single spinal nerve and multiple sympathetic trunk vertebral levels. Multiple TPV injections may be needed to provide adequate thoracic analgesia in dogs undergoing thoracic surgery.  相似文献   

19.

Objective

To evaluate skin temperature increase as an early predictive measure for evaluating epidural and femoral-sciatic block success in dogs.

Study design

Prospective clinical trial.

Animals

A total of 29 dogs undergoing orthopaedic surgery on one hindlimb.

Methods

Dogs were anaesthetized and placed into lateral recumbency with the affected limb uppermost and the coat was clipped. Baseline infrared thermographic images (T0) of the affected limb, of the paw pad of the affected leg and of the ipsilateral paw pad were taken. Subsequently, dogs were administered either an epidural (EPI; n = 11) or a femoral–sciatic block (FS; n = 18) using bupivacaine 1 mg kg?1. Then, 2 minutes after placement of the block, thermographic images were obtained every 3 minutes for a total of four measurements (T1–T4) and surgery was commenced. Rescue analgesia consisting of fentanyl 1 μg kg?1 was administered if needed. A regional block was considered successful if the dose of fentanyl administered was less than the lower 95% confidence interval of the geometric mean of the total fentanyl used in each group. A ≥ 1 °C increase of skin temperature was considered as the minimum increase required for detection of a successful block.

Results

A total of 12 out of 18 blocks in the FS and eight of 11 in the EPI group were considered successful based on fentanyl consumption. Out of these, only four of 12 in the FS and one of eight in the EPI group developed an increase in temperature of ≥ 1 °C. Contrarily, four of six of the nonsuccessful cases in the FS and three of three in the EPI group developed an increase in temperature of ≥ 1 °C.

Conclusions and clinical relevance

Contrary to reports in humans, thermography did not indicate regional block success prior to surgery in dogs. However further studies under more controlled conditions are needed to determine whether thermography can be used to indicate failure of regional blockade.  相似文献   

20.

Objective

To compare incidence and duration of postinduction apnoea in dogs after premedication with methadone and acepromazine (MA) or methadone and dexmedetomidine (MD) followed by induction with propofol (P) or alfaxalone (A).

Study design

Prospective, randomized clinical trial.

Animals

A total of 32 American Society of Anesthesiologists class I dogs (15 females, 17 males), aged between 4 months and 4 years, weighing between 3 and 46 kg.

Methods

Dogs were randomly allocated to be administered MA+P, MA+A, MD+P or MD+A (methadone 0.5 mg kg?1 and acepromazine 0.05 mg kg?1 or dexmedetomidine 5 μg kg?1). Induction agents were administered intravenously via syringe driver (P at 4 mg kg?1 minute?1 or A at 2 mg kg?1 minute?1) until successful endotracheal intubation and the endotracheal tube connected to a circle system with oxygen flow at 2 L minute?1. Oxygen saturation of haemoglobin (SpO2), end tidal partial pressure of carbon dioxide and respiratory rate were monitored continuously. If apnoea (≥ 30 seconds without breathing) occurred, the duration until first spontaneous breath was measured. If SpO2 decreased below 90% the experiment was stopped and manual ventilation initiated. Data were analysed with general linear models with significance set at p ≤ 0.05.

Results

There was no statistical difference in the incidence (11 of 16 dogs in A groups and 12 of 16 dogs in P groups), or mean ± standard deviation duration (A groups 125 ± 113 seconds, P groups 119 ± 109 seconds) of apnoea. The SpO2 of one dog in the MD+P group decreased below 90% during the apnoeic period.

Conclusions and clinical relevance

Propofol and alfaxalone both cause postinduction apnoea and the incidence and duration of apnoea is not influenced by the use of acepromazine or dexmedetomidine in premedication. Monitoring of respiration is recommended when using these premedication and induction agent combinations.  相似文献   

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