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1.
Sedatives and anaesthetics are known to cause changes in the regional cerebral blood flow. In dogs intramuscular sedation with medetomidine, a potent sedative frequently used in veterinary medicine, is sometimes indicated prior to intravenous injection of 99mTechnetium-Ethyl Cysteinate Dimer (99mTc-ECD) in brain perfusion studies using Single Photon Emission Computed Tomography (SPECT). Based on the knowledge of the distribution of alpha2-receptors in the brain, we hypothesized altered regional brain perfusion in dogs receiving medetomidine prior to 99mTc-ECD. Two conditions were compared in 10 dogs; tracer injection before and after intramuscular sedation with medetomidine. In our study, medetomidine caused a significantly higher tracer uptake in all brain regions. Semi-quantification of brain perfusion rendered a lower perfusion index in the subcortical region and an imbalance between left and right cortical perfusion induced by medetomidine. This study shows that caution is needed when quantifying the brain perfusion indices under medetomidine sedation.  相似文献   

2.
Pancreatitis is the most frequent disease affecting the exocrine pancreas in dogs and reliable diagnostic techniques for predicting fatal complications are lacking. Contrast‐enhanced ultrasound (CEUS) improves detection of tissue perfusion as well as organ lesion vascular pattern. Objectives of this prospective case control study were to compare perfusion characteristics and enhancement patterns of the pancreas in healthy dogs and dogs with pancreatitis using CEUS. Ten healthy dogs and eight dogs with pancreatitis were selected based on physical examination, abdominal ultrasound, and blood analysis findings. A CEUS study of the pancreas was performed for each dog and two observers who were aware of clinical status used advanced ultrasound quantification software to analyze time‐intensity curves. Perfusion patterns were compared between healthy and affected dogs. In dogs with acute pancreatitis, mean pixel and peak intensity of the pancreatic parenchyma was significantly higher than that of normal dogs (P = 0.05) in between 6 and 60 s (P = <0.0001–0.046). This corresponds to a 311% increase in mean pixel intensity in dogs with acute pancreatitis compared to healthy dogs. Wash‐in rates were greater and had a consistently steeper slope to peak in dogs with pancreatitis as opposed to healthy dogs. All dogs with pancreatitis showed a decrease in pixel intensity 10–15 days after the initial examination (P = 0.011) and their times to peak values were prolonged compared to the initial exam. Findings from the current study supported the use of CEUS for diagnosing pancreatitis, pancreatic necrosis, and disease monitoring following therapy in dogs.  相似文献   

3.
OBJECTIVE: To evaluate the effects of the alpha2-adrenoceptor agonist medetomidine on respiratory rate (RR), tidal volume (V(T)), minute volume (V(M)), and central respiratory neuromuscular drive as determined by inspiratory occlusion pressure (IOP) during increasing fractional inspired concentrations of carbon dioxide (FiCO2) in conscious dogs. ANIMALS: 6 healthy dogs (3 males and 3 females). PROCEDURE: Dogs were administered 0, 5, or 10 microg of medetomidine/kg i.v. We measured RR, V(T), V(M), and IOP for the first 0.1 second of airway occlusion (IOP0.1) during FiCO2 values of 0%, 2.5%, 5.0%, and 75% at 15 minutes before and 5, 30, and 60 minutes after administration of medetomidine. RESULTS: Increases in FiCO2 significantly increased RR, V(T), and V(M). The i.v. administration of 5 and 10 microg of medetomidine/kg significantly decreased RR and V(M) at 5, 30, and 60 minutes for FiCO2 values of 2.5% and 5.0% and at 30 and 60 minutes for an FiCO2 value of 75%. The IOP0.1 was decreased after 30 minutes only for an FiCO2 value of 7.5% in dogs administered 5 and 10 microg of medetomidine/kg. The IOP0.1 was decreased at 60 minutes after administration of 10 microg of medetomidine/kg for an FiCO2 value of 7.5%. CONCLUSIONS AND CLINICAL RELEVANCE: The i.v. administration of medetomidine decreases RR, V(M), and central respiratory drive in conscious dogs. Medetomidine should be used cautiously and with careful monitoring in dogs with CNS depression or respiratory compromise.  相似文献   

4.
ObjectiveTo evaluate the effects and utility of tiletamine–zolazepam–medetomidine (TZM) and ketamine–medetomidine (KM) for anesthesia of Amur leopard cats (Prionailurus bengalensis euptailurus).Study designProspective, randomized experimental trial.AnimalsA total of six female (3.70 ± 0.49 kg) and six male (5.03 ± 0.44 kg; mean ± standard deviation) Amur leopard cats aged 2–6 years.MethodsEach animal was administered four protocols separated by ≥3 weeks. Each protocol included medetomidine (0.05 mg kg–1) combined with tiletamine–zolazepam (1 mg kg–1; protocol MTZLO); tiletamine–zolazepam (2 mg kg–1; protocol MTZHI); ketamine (2 mg kg–1; protocol MKLO); or ketamine (4 mg kg–1; MKHI) administered intramuscularly. At time 0 (onset of lateral recumbency) and 30 minutes, heart rate (HR), respiratory rate (fR), rectal temperature, noninvasive mean arterial pressure (MAP) and hemoglobin oxygen saturation (SpO2) were recorded. Times to onset of lateral recumbency, duration of anesthesia and time to standing were recorded.ResultsOverall, animals were anesthetized with all protocols within 10 minutes, anesthesia was maintained ≥57 minutes, and recovery (time from the first head lift to standing) was completed within 5 minutes. During anesthesia with all protocols, HR, fR, rectal temperature, SpO2 and MAP were 99–125 beats minute–1, 33–44 breaths minute–1, 37.6–39.4 °C, 90–95% and 152–177 mmHg, respectively. No adverse event was observed.Conclusions and clinical relevanceTZM and KM at various dosages resulted in rapid onset of anesthesia, duration of >57 minutes and rapid recovery without administration of an antagonist. Accordingly, all these combinations are useful for anesthetizing Amur leopard cats and for performing simple procedures. However, the low doses of the anesthetic agents are recommended because there was no difference in duration of anesthesia between the dose rates studied.  相似文献   

5.
This prospective case study aimed to clarify the clinical significance of contrast-enhanced ultrasound (CEUS) for the differential diagnosis of canine adrenal tumors. Forty-three client-owned dogs with adrenal tumors were included. All dogs underwent CEUS, which was evaluated qualitatively and quantitatively. The peak signal intensity (PI), time to peak signal intensity (TPI), mean transit time (MTT), upslope, and downslope were calculated for each time-intensity curve. The histopathological diagnosis of each resected mass was compared with the CEUS findings and parameters. Enhancement distribution, vascularity, tortuous nourishing vessels, enhancement pattern, and late-phase enhancement did not differ significantly between adrenal cortical adenoma (CA), adenocarcinoma (CAC), and pheochromocytoma (PHEO) in qualitative assessment. In PHEO, the TPI was significantly more rapid compared with that in CA (P=0.0287) and CAC (P=0.0404). The MTT in PHEO was significantly shorter than that in CA (P=0.0016) and CAC (P=0.0003). Upslope in PHEO was larger than that in CAC (P=0.0406). Downslope in PHEO was significantly larger than that in CA (P=0.0048) and CAC (P=0.0018). A receiver operating characteristic curve analysis demonstrated that the area under the MTT curve yielded 0.91 for distinguishing PHEO from adrenocortical tumors in dogs; an MTT cut-off value less than 6,225 msec yielded a sensitivity of 69%, specificity of 94%, and likelihood ratio of 12.46. CEUS appears to be clinically applicable for the differential diagnosis between cortical and medullary origins of primary adrenal tumors in dogs.  相似文献   

6.
ObjectiveTo investigate the effect of medetomidine on plasma glucose and insulin concentrations in dogs with insulinoma and in healthy dogs undergoing anesthesia and surgery.AnimalsTwenty–five dogs with insulinoma and 26 healthy dogs.MethodsIn dogs with insulinoma, medetomidine (5 μg kg?1) was randomly included (n = 12) or omitted (n = 13) from the pre–anesthetic medication protocol, which typically contained an opioid and an anticholinergic. Healthy dogs received medetomidine (5 μg kg?1; n = 13) or acepromazine (0.04 mg kg?1; n = 13) plus an opioid (morphine 0.5 mg kg?1) and an anticholinergic (atropine 0.04 mg kg?1) as pre–anesthetic medications. Pre–anesthetic medications were given intramuscularly. Plasma glucose and insulin concentrations were measured before (sample 1) and 30 minutes after pre–anesthetic medication (sample 2), and at the end of surgery in dogs with insulinoma or at 2 hours of anesthesia in healthy dogs (sample 3). Glucose requirement to maintain intra–operative normoglycemia in dogs with insulinoma was quantified and compared. Data were analyzed with anova and Bonferroni post–test, t–tests or chi–square tests as appropriate with p < 0.05 considered significant. Data are shown as mean ± SD.ResultsMedetomidine significantly decreased plasma insulin concentrations and increased plasma glucose concentrations in healthy dogs and those with insulinoma. These variables did not change significantly in the dogs not receiving medetomidine. In the dogs with insulinoma, intra–operative glucose administration rate was significantly less in the animals that received medetomidine compared to those that did not.ConclusionsPre–anesthetic administration of medetomidine significantly suppressed insulin secretion and increased plasma glucose concentration in dogs with insulinoma and in healthy dogs undergoing anesthesia and surgery.Clinical relevanceThese findings support the judicious use of medetomidine at low doses as an adjunct to the anesthetic management of dogs with insulinoma.  相似文献   

7.
OBJECTIVE: To compare 3 dose levels of medetomidine and dexmedetomidine for use as premedicants in dogs undergoing propofol-isoflurane anesthesia. ANIMALS: 6 healthy Beagles. PROCEDURE: Dogs received medetomidine or dexmedetomidine intravenously at the following dose levels: 0.4 microg of medetomidine or 0.2 microg of dexmedetomidine/kg of body weight (M0.4/D0.2), 4.0 microg of medetomidine or 2.0 microg of dexmedetomidine/kg (M4/D2), and 40 microg of medetomidine or 20 microg of dexmedetomidine/kg (M40/D20). Sedation and analgesia were scored before induction. Anesthesia was induced with propofol and maintained with isoflurane. End-tidal isoflurane concentration, heart rate, and arterial blood pressures and gases were measured. RESULTS: Degrees of sedation and analgesia were significantly affected by dose level but not drug. Combined mean end-tidal isoflurane concentration for all dose levels was higher in dogs that received medetomidine, compared with dexmedetomidine. Recovery time was significantly prolonged in dogs treated at the M40/D20 dose level, compared with the other dose levels. After induction, blood pressure decreased below reference range and heart rate increased in dogs treated at the M0.4/D0.2 dose level, whereas blood pressure was preserved in dogs treated at the M40/D20 dose level. However, dogs in these latter groups developed profound bradycardia and mild metabolic acidosis during anesthesia. Treatment at the M4/D2 dose level resulted in more stable cardiovascular effects, compared with the other dose levels. In addition, PaCO2 was similar among dose levels. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine is at least as safe and effective as medetomidine for use as a premedicant in dogs undergoing propofol-isoflurane anesthesia.  相似文献   

8.
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9.
Extrahepatic‐congenital portosystemic shunt is a vascular anomaly that connects the portal vein to the systemic circulation and leads to a change in hepatic microvascular perfusion. However, an assessment of hepatic microvascular perfusion is limited by conventional diagnostic modalities. The aim of this prospective, exploratory study was to assess hepatic microvascular perfusion in dogs with extrahepatic‐congenital portosystemic shunt using contrast‐enhanced ultrasonography (CEUS) using perfluorobutane (Sonazoid®). A total of 17 dogs were included, eight healthy dogs and nine with extrahepatic‐congenital portosystemic shunt. The time‐to‐peak (TTP), rising time (RT), and rising rate (RR) in the hepatic artery, portal vein, and hepatic parenchyma, as well as the portal vein‐to‐hepatic parenchyma transit time (ΔHP‐PV) measured from time‐intensity curve on CEUS were compared between healthy and extrahepatic‐congenital portosystemic shunt dogs. The RT of the hepatic artery in extrahepatic‐congenital portosystemic shunt dogs was significantly earlier than in healthy dogs (P = 0.0153). The TTP and RT of the hepatic parenchyma were significantly earlier in extrahepatic‐congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018 and P = 0.0024, respectively). ΔHP–PV was significantly shorter in extrahepatic‐congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018). CEUS effectively revealed changes in hepatic microvascular perfusion including hepatic artery, portal vein, and hepatic parenchyma simultaneously in extrahepatic‐congenital portosystemic shunt dogs. Rapid hepatic artery and hepatic parenchyma enhancements may reflect a compensatory increase in hepatic artery blood flow (arterialization) caused by a decrease in portal vein blood flow and may be used as an additional diagnostic test to distinguish extrahepatic‐congenital portosystemic shunt dogs from healthy dogs.  相似文献   

10.
ObjectiveTo evaluate the sedative effects of intravenous (IV) medetomidine (1 μg kg?1) and butorphanol (0.1 mg kg?1) alone and in combination in dogs.Study designProspective, blinded, randomized clinical trial.AnimalsSixty healthy (American Society of Anesthesiologists I) dogs, aged 6.2 ± 3.2 years and body mass 26 ± 12.5 kg.MethodsDogs were assigned to four groups: Group S (sodium chloride 0.9% IV), Group B (butorphanol IV), Group M (medetomidine IV) and Group MB (medetomidine and butorphanol IV). The same clinician assessed sedation before and 12 minutes after administration using a numerical scoring system in which 19 represented maximum sedation. Heart rate (HR), respiratory rate, pulse quality, capillary refill time and rectal temperature were recorded after each sedation score assessment. Sedation scores, sedation score difference (score after minus score before administration) and patient variables were compared using one-way anova for normally distributed variables and Kruskal–Wallis test for variables with skewed distributions and/or unequal variances. Where significance was found, further evaluation used Bonferroni multiple comparisons for pair-wise testing.ResultsBreed, sex, neuter status, age and body mass did not differ between groups. Sedation scores before substance administration were similar between groups (p = 0.2). Sedation scores after sedation were significantly higher in Group MB (mean 9.5 ± SD 5.5) than in group S (2.5 ± 1.8) (p < 0.001), group M (3.1 ± 2.5) (p < 0.001) and group B (3.7 ± 2.0) (p = 0.003). Sedation score difference was significantly higher in Group MB [7 (0–13)] than in Group S [0 (?1 to 4)] (p < 0.001) and Group M [0 (0–6)] (p < 0.001). HR decreased significantly in Groups M and MB compared with Group S (p < 0.05).Conclusion and clinical relevanceLow-dose medetomidine 1 μg kg?1 IV combined with butorphanol 0.1 mg kg?1 IV produced more sedation than medetomidine or butorphanol alone. HR was significantly decreased in both medetomidine groups.  相似文献   

11.
Alpha2 agonists have a significant role in epidural anaesthetic techniques. However, there are few reports regarding epidural administration of these drugs especially in small animals ( Greene et al. 1995; Keegan et al. 1995; Vesal et al. 1996 ). This study compared the haemodynamic effects of xylazine and medetomidine after epidural injection in dogs. Six dogs (four females and two males) weighing 27.5 ± 3.39 kg, aged 5.6 ± 1.42 years were studied on two separate occasions one month apart. Dogs were sedated with 0.5 mg kg?1 diazepam IM and 0.1 mg kg?1 acepromazine IM. After 20 minutes, a lumbosacral epidural injection of 0.25 mg kg?1 xylazine was administered (group X). One month later, following the same sedation, 15 µg kg?1 medetomidine was administered epidurally (group M). Haemodynamic variables (ECG and indirect blood pressure (Doppler)), respiratory rate and rectal temperature were recorded before (baseline) and then every 5 minutes after the epidural injection, up to 60 minutes. Differences between groups were compared by a paired t‐test. Within group changes were compared to basal values by anova . A p‐value of < 0.05 was considered statistically significant. Both groups showed significant reductions in heart rate (106.3 ± 7.7 beats minute?1 baseline versus 67.7 ± 7.6 (group M); 91 ± 3.8 baseline versus 52.3 ± 9 (group X)) and mean arterial blood pressure (113.1 ± 12.3 mm Hg baseline versus 87 ± 11 (group M); 118 ± 7 baseline versus 91 ± 14 (group X)). There were no differences between groups in these variables. After epidural injection, first degree atrioventricular block was recorded significantly more often in group X (50% against 33%) but second degree block was significantly more frequent in group M (66% against 33%). Also 50% of dogs in group X and 66% in group M showed sinus arrest. Respiratory rate decreased significantly in both groups following the epidural injection (20.66 ± 0.66 minute?1 baseline versus 16.33 ± 4.77 (group M); 37.66 ± 0.56 baseline versus 16.33 ± 1.81 group X), but no differences between groups were observed. Rectal temperature decreased significantly in group X (38.16 ± 0.21) with respect to the basal measurement (39.30 ± 0.14 °C). In group M, there was no significant reduction in temperature, however, no statistical difference in rectal temperature was found between groups. This study shows that 0.25 mg kg?1 xylazine and 15 µg kg?1 medetomidine produce similar, significant cardiovascular and respiratory changes following lumbosacral epidural administration in dogs.  相似文献   

12.
The purpose of this study was to determine the cardiovascular, analgesic, and sedative effects of IV medetomidine (M, 20 µg kg?1), medetomidine–hydromorphone (MH, 20 µg kg?1 ? 0.1 mg kg?1), and medetomidine–butorphanol (MB, 20 µg kg?1 ? 0.2 mg kg?1) in dogs. Using a randomized cross‐over design and allowing 1 week between treatments, six healthy, mixed‐breed dogs (five males and one female) weighing 20 ± 3 kg, were induced to anesthesia by face‐mask administration of 2.9% ET sevoflurane to facilitate instrumentation prior to administration of the treatment combinations. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), mean pulmonary arterial pressure (PAP), pulmonary arterial occlusion pressure (PAOP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output via thermodilution using 5 mL of 5% dextrose, and recording the average of the three replicate measurements. Cardiac index (CI) and systemic (SVR) and pulmonary vascular resistances were calculated. After instrumentation was completed, administration of sevoflurane was discontinued, and the dogs were allowed to recover for 30 minutes prior to administration of the treatment drugs. After collection of the baseline samples for blood gas analysis and recording the baseline cardiovascular variables, the test agents were administered IV over 10 seconds and the CV variables recorded at 5, 10, 15, 30, 45, and 60 minutes post‐injection. In addition, arterial blood was sampled for blood gas analysis at 15 and 45 minutes following injection. Intensity and duration of analgesia (assessed by toe‐pinch response using a hemostat) and level of sedation were evaluated at the above time points and at 75 and 90 minutes post‐injection. Data were analyzed using anova for repeated measures with posthoc differences between means identified using Bonferroni's method (p < 0.05). Administration of M, MH, or MB was associated with increases in SAP, MAP, DAP, PAP, PAOP, CVP, SVR, and TEMP and with decreases in HR and CI. No differences in CV variables between treatment groups were identified at any time. PaO2 increased over time in all groups and was significantly higher when MH was compared with M. At 45 minutes, PaO2 tended to decrease over time and was significantly lower when MH and MB were compared with M at 15 minutes. Analgesia scores for MH and MB were significantly higher compared with M through 45 minutes, while analgesia scores for MH were significantly higher compared with M through 90 minutes. Sedation scores were higher for MH and MB compared with M throughout 90 minutes. Durations of lateral recumbency were 108 ± 10.8, 172 ± 15.5, and 145 ± 9.9 minutes for M, MH, and MB, respectively. We conclude that MH and MB are associated with improved analgesia and sedation and have similar CV effects when compared with M.  相似文献   

13.
In the present study, we compare a new carbon dioxide (CO2) absorbent, Yabashi lime® with a conventional CO2 absorbent, Sodasorb® as a control CO2 absorbent for Compound A (CA) and Carbon monoxide (CO) productions. Four dogs were anesthetized with sevoflurane. Each dog was anesthetized with four preparations, Yabashi lime® with high or low-flow rate of oxygen and control CO2 absorbent with high or low-flow rate. CA and CO concentrations in the anesthetic circuit, canister temperature and carbooxyhemoglobin (COHb) concentration in the blood were measured. Yabashi lime® did not produce CA. Control CO2 absorbent generated CA, and its concentration was significantly higher in low-flow rate than a high-flow rate. CO was generated only in low-flow rate groups, but there was no significance between Yabashi lime® groups and control CO2 absorbent groups. However, the CO concentration in the circuit could not be detected (≤5ppm), and no change was found in COHb level. Canister temperature was significantly higher in low-flow rate groups than high-flow rate groups. Furthermore, in low-flow rate groups, the lower layer of canister temperature in control CO2 absorbent group was significantly higher than Yabashi lime® group. CA and CO productions are thought to be related to the composition of CO2 absorbent, flow rate and canister temperature. Though CO concentration is equal, it might be safer to use Yabashi lime® with sevoflurane anesthesia in dogs than conventional CO2 absorbent at the point of CA production.  相似文献   

14.
The effects of 2 different continuous rate infusions (CRIs) of medetomidine over an 8-hour period on sedation score, selected cardiopulmonary parameters, and serum levels of medetomidine were evaluated in 6 healthy, conscious dogs using a crossover study design. The treatment groups were: CONTROL = saline bolus followed by saline CRI; MED1 = 2 μg/kg body weight (BW) medetomidine loading dose followed by 1 μg/kg BW per hour CRI; and MED2 = 4 μg/kg BW medetomidine loading dose followed by 2 μg/kg BW per hour CRI. Sedation score (SS), heart rate (HR), respiratory rate (RR), temperature (TEMP), systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP), arterial and mixed venous blood gas analyses, lactate, and plasma levels of medetomidine were evaluated at baseline, at various intervals during the infusion, and 2 h after terminating the infusion. Statistical analysis involved a repeated measures linear model. Both infusion rates of medetomidine-induced dose-dependent increases in SS and dose-dependent decreases in HR, SAP, MAP, and DAP were measured. Respiratory rate (RR), TEMP, central venous pH, central venous oxygen tension, and oxygen extraction ratio also decreased significantly in the MED2 group at certain time points. Arterial oxygen and carbon dioxide tensions were not significantly affected by either infusion rate. In healthy dogs, both infusion rates of medetomidine-induced clinically relevant sedative effects, accompanied by typical alpha2 agonist-induced hemodynamic effects, which plateaued during the infusion and subsequently returned to baseline. While additional studies in unhealthy animals are required, the results presented here suggest that medetomidine infusions at the doses studied may be useful in canine patients requiring sedation for extended periods.  相似文献   

15.
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16.
ObjectiveTo quantify the effects of medetomidine on the onset and duration of vecuronium-induced neuromuscular blockade in dogs.Study designRandomized, prospective clinical study.AnimalsTwenty-four, healthy, client-owned dogs of different breeds, aged between 6 months and 10 years and weighing between 5.0 and 40.0 kg undergoing elective surgery.MethodsDogs were randomly allocated to two groups. Pre-anaesthetic medication in group M+ was intramuscular acepromazine (ACP) 25 μg kg−1, morphine 0.5 mg kg−1 and medetomidine 5 μg kg−1. Group M− received ACP and morphine only, at the same dose rate. After induction with thiopental, anaesthesia was maintained with halothane in oxygen and nitrous oxide. End-tidal halothane concentration was maintained at 1.1%. Neuromuscular blockade was produced with intravenous vecuronium (50 μg kg−1) and monitored using a train of four stimulus applied at the ulnar nerve. The times taken for loss and reappearance of the four evoked responses (twitches [T]) were recorded. Normal and nonparametric data were analysed with an independent t-test and Mann-Whitney's U-test, respectively.ResultsThe fourth twitch (T4) disappeared at similar times in each group: 107 ± 19; [72–132] (mean ± SD; [range]) seconds in M+ and 98 ± 17 [72–120] seconds in M− dogs. The first twitch (T1) was lost at 116 ± 15; [96–132] seconds in group M+ and 109 ± 19; [72–132] seconds in M−. The fourth twitch returned significantly earlier in M+ dogs: 20.8 ± 3.8 [14–28] minutes compared with 23.8 ± 2.7 [20–27] minutes (p = 0.032). The duration of drug effect (T4 absent) was significantly shorter (p = 0.027) in M+ (18.9 ± 3.7 minutes) compared with M− dogs (22.2 ± 2.9 minutes). The recovery rate (interval between reappearance of T1 and T4) was significantly more rapid (p = 0.0003) in medetomidine recipients (3.0 ± 1.2 versus 5.2 ± 1.3 minutes).Conclusion and clinical relevance Medetomidine 5 μg kg−1 as pre-anaesthetic medication shortened the duration of effect of vecuronium in halothane-anaesthetized dogs and accelerated recovery, but did not affect the onset time. These changes are of limited clinical significance.  相似文献   

17.
OBJECTIVE: To evaluate effects of medetomidine on anesthetic dose requirements, cardiorespiratory variables, plasma cortisol concentrations, and behavioral pain scores in dogs undergoing ovariohysterectomy. DESIGN: Randomized, prospective study. ANIMALS: 12 healthy Walker-type hound dogs. PROCEDURE: Dogs received medetomidine (40 micrograms/kg [18.2 micrograms/lb] of body weight, i.m.; n = 6) or saline (0.9% NaCl) solution (1 ml, i.m.; 6) prior to anesthesia induction with thiopental; thiopental dose needed for endotracheal intubation was compared between groups. Ovariohysterectomy was performed during halothane anesthesia. Blood samples were obtained at various times before drug administration until 300 minutes after extubation. Various physiologic measurements and end-tidal halothane concentrations were recorded. RESULTS: In medetomidine-treated dogs, heart rate was significantly lower than in controls, and blood pressure did not change significantly from baseline. Plasma cortisol concentrations did not increase significantly until 60 minutes after extubation in medetomidine-treated dogs, whereas values in control dogs were increased from time of surgery until the end of the recording period. Control dogs had higher pain scores than treated dogs from extubation until the end of the recording period. CONCLUSION AND CLINICAL RELEVANCE: Administration of medetomidine reduced dose requirements for thiopental and halothane and provided postoperative analgesia up to 90 minutes after extubation. Dogs undergoing ovariohysterectomy by use of thiopental induction and halothane anesthesia benefit from analgesia induced by medetomidine administered prior to anesthesia induction. Additional analgesia is appropriate 60 minutes after extubation.  相似文献   

18.
ObjectiveTo evaluate the dexmedetomidine‐induced reduction in organ blood flow with quantitative contrast‐enhanced ultrasound (CEUS) method and to observe the influence of MK‐467 on such reduction.Study designRandomized cross‐over study.AnimalsSix adult purpose‐bred laboratory beagle dogs (mean body weight 15.3 ± 1.9 kg).MethodsContrast‐enhanced ultrasound was performed on six conscious healthy laboratory beagles. The animals on separate occasions underwent three treatments: awake without any medication (CTRL), dexmedetomidine 10 μg kg?1 (DEX) and DEX + MK‐467 500 μg kg?1 (DMK) intravenously (IV). The kidney (10–15 minutes post‐treatment), spleen (25–30 minutes post‐treatment), small intestine (40–45 minutes post‐treatment) and liver (50–55 minutes post‐treatment) were examined with CEUS. A time curve was generated and the following perfusion parameters were analysed: arrival time (AT), time to peak from injection (TTPinj), peak intensity (PI) and wash‐in rate (Wi). In addition to CEUS, renal glomerular filtration rate was indirectly estimated by the rate of iohexol elimination.ResultsAT and TTPinj were significantly higher for DEX than for CTRL in all studied organs. The same parameters were significantly higher for DEX than for DMK in the kidney, spleen and small intestine. PI was significantly lower for DEX than for CTRL or DMK in the kidney. Wi was significantly lower for DEX than for CTRL or DMK in the kidney and significantly lower than for CTRL only in the small intestine. Plasma concentration of iohexol was significantly higher after DEX than CTRL administration.ConclusionsContrast‐enhanced ultrasound was effective in detecting DEX‐induced changes in blood flow. MK‐467 attenuated these changes.Clinical relevanceClinicians should consider the effects of the sedation protocol when performing CEUS. Addition of MK‐467 might beneficially impact the haemodynamic function of sedation with alpha‐2 adrenoceptor agonists.  相似文献   

19.
ObjectiveTo assess the effects of cytochrome P450 (CYP) inhibitors (ketoconazole, chloramphenicol, trimethoprim, fluoxetine, cimetidine and medetomidine) in various combinations on the pharmacokinetics of oral methadone in Greyhound dogs to determine the specific effects of the different inhibitors and if a clinically relevant interaction occurs.Study designNon-randomized, sequential design.AnimalsSix healthy Greyhound dogs (three male, three female).MethodsCanine CYP inhibitors (ketoconazole, chloramphenicol, trimethoprim, fluoxetine, cimetidine and medetomidine) were administered in varying combinations prior to the administration of oral methadone. Plasma was obtained from each dog to enable the determination of methadone and CYP inhibitor drug concentrations using liquid chromatography with either mass spectrometry or ultraviolet detection.ResultsSignificant increases in the area under the curve (AUC) and maximum plasma concentrations (CMAX) of methadone occurred in all groups administered chloramphenicol. The AUC (6 hours ng mL−1) and CMAX (6 ng mL−1) of methadone significantly increased to 541 hours ng mL−1 and 47.8 ng mL−1, respectively, when methadone was administered with chloramphenicol as a sole inhibitor. There were no significant effects of CYP inhibitors other than chloramphenicol on methadone pharmacokinetics, which suggests that chloramphenicol was primarily responsible for the pharmacokinetic interaction.Conclusions and clinical relevanceThis study demonstrated significant effects of chloramphenicol on the pharmacokinetics of oral methadone. Further studies should investigate the effects of chloramphenicol on methadone pharmacokinetics in multiple dog breeds and examine whether oral methadone would be an effective analgesic in dogs. In addition, the safety of chloramphenicol and its effects on the pharmacokinetics of parenteral methadone warrant assessment.  相似文献   

20.
This study evaluated anesthesia quality, degree of analgesia and cardiorespiratory parameters after intramuscular (IM) injection of a combination of butorphanol (0.1 mg/kg), medetomidine (10 µg/kg) and alfaxalone (1.5 mg/kg) in ten healthy adult Beagle dogs. Rectal temperature (T), heart rate (HR), respiratory rate (fR), arterial pressure, arterial blood gases and M-mode echocardiographic left ventricular (LV) indices were measured before drug administration and every 10 min thereafter until extubation. Mean duration of anesthesia, recovery and analgesia were 89 ± 17, 6 ± 1 and 80 ± 12 min. HR, fR, partial pressure of arterial CO2 and O2, arterial pressure, and LV contractility were significantly altered during anesthesia. IM administration of the drug combination provided acceptable anesthesia, but produced substantial cardiorespiratory suppression.  相似文献   

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