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Comparison of systemic effects of midazolam, ketamine, and isoflurane anaesthesia in rabbits
2019
Atalan, Güneri | Atalan, Gültekin | Erol, Hanifi | Erol, Muharrem | Atasever, Ayhan | Doğan, Zafer | Güneş, Vehbi | Yönez, M Kaan | Keleş, Ihsan
Introduction: Clinical doses of anaesthetic agents were administered to rabbits and effects on the brain, heart, and liver were investigated biochemically and histopathologically. Material and Methods: The rabbits were randomly divided into three main groups (16 rabbits each) and each group into study (n = 8) and control (n = 8) groups. All study group rabbits received 3 mg/kg of midazolam (M) intramuscularly. Group 1.1 (M) received nothing further, group 2.1 (MK) also received 25 mg/kg of ketamine, and group 3.1 (MKI) besides ketamine was also given 2% isoflurane to induce anaesthesia for 30 min. NaCl solution in the same volume as midazolam and ketamine was injected into the controls. Results: In clinical evaluation significant differences were detected in respiratory and heart rates. In blood gas analysis the PO2 and PCO2 values showed statistical differences in anaesthesia intervals. Significant biochemical value changes were recorded in creatine kinase-Mb, glucose, and total protein. Histopathological liver examinations revealed higher total apoptotic and normal cell numbers in the MK than in the M and MKI groups. Apoptotic cell numbers were statistically significant in M and MK groups. Conclusion: Anaesthetic agents may increase programmed apoptosis. The MKI anaesthetics combination was found to cause less cell destruction in general than the other study groups. It was indicated that MKI was the safer anaesthetic combination in rabbits.
显示更多 [+] 显示较少 [-]Effects of tiletamine-xylazine-tramadol combination and its specific antagonist on AMPK in the brain of rats
2019
Ma, Ning | Li, Xin | Wang, Hong-bin | Gao, Li | Xiao, Jian-hua
Introduction: Tiletamine-xylazine-tramadol (XFM) has few side effects and can provide good sedation and analgesia. Adenosine 5’-monophosphate-activated protein kinase (AMPK) can attenuate trigeminal neuralgia. The study aimed to investigate the effects of XFM and its specific antagonist on AMPK in different regions of the brain. Material and Methods: A model of XFM in the rat was established. A total of 72 Sprague Dawley (SD) rats were randomly divided into three equally sized groups: XFM anaesthesia (M group), antagonist (W group), and XFM with antagonist interactive groups (MW group). Eighteen SD rats were in the control group and were injected intraperitoneally with saline (C group). The rats were sacrificed and the cerebral cortex, cerebellum, hippocampus, thalamus, and brain stem were immediately separated, in order to detect AMPKα mRNA expression by quantitative PCR. Results: XFM was able to increase the mRNA expression of AMPKα1 and AMPKα2 in all brain regions, and the antagonist caused the opposite effect, although the effects of XFM could not be completely reversed in some areas. Conclusion: XFM can influence the expression of AMPK in the central nervous system of the rat, which can provide a reference for the future development of anaesthetics for animals.
显示更多 [+] 显示较少 [-]Pilot study comparing serum chemotherapy levels after intra-arterial and intravenous administration in dogs with naturally occurring urinary tract tumors
2019
Kirsch, M. | Weisse, C. | Berent, A. | Clifford, C. | Leibman, N. | Wittenburg, L. | Solomon, S. B. | Lamb, K.
The proposed advantages of intra-arterial chemotherapy (IAC) are based on the premises of local dose escalation to the tumor and reduced availability of systemic drugs. There is a lack of objective pharmacokinetic data to confirm the advantage of IAC in dogs with naturally occurring urogenital tumors. The objective of this study was to determine if IAC administration in urogenital tumors would result in decreased systemic drug exposure when compared to intravenous routes. Twenty-two dogs with naturally occurring urogenital tumors were enrolled in this prospective case-controlled study. Mitoxantrone, doxorubicin, or carboplatin were administered by IAC and intravenous routes [intravenous awake (intravenous chemotherapy - IVC) and under general anesthesia (IVGAC)] 3 weeks apart. Serum assays were used to determine the extent of systemic drug exposure. Dose-normalized peak systemic serum concentration (Cmax) and area under the serum drug concentration-time curve (AUC) were used to quantify systemic exposure. A total of 26 mitoxantrone treatments were administered to 10 dogs. While there was no significant difference in Cmax, the AUC was significantly lower after IAC compared with IVGAC. Ten doxorubicin treatments were administered to 5 dogs. There were no significant differences in Cmax or AUC. A total of 14 carboplatin treatments were administered to 7 dogs. The Cmax was significantly lower for IAC compared to IVC, while the AUC values were equivocal. This study demonstrates certain lower serum values may be achieved after IAC delivery of carboplatin and mitoxantrone. These chemotherapy agents may have a preferred pharmacological profile for regional chemotherapy delivery in dogs with urogenital tumors.
显示更多 [+] 显示较少 [-]Effects of injectable dexmedetomidine-ketamine-midazolam and isoflurane inhalation anesthetic protocols on ocular variables in captive black-tailed prairie dogs (Cynomys ludovicianus)
2019
Roberts, Jordan K. | Meekins, Jessica M. | Browning, Geoffrey R. | Beaufrere, Hugues | Eshar, David
OBJECTIVE To evaluate the effects of injectable dexmedetomidine-ketamine-midazolam (DKM) and isoflurane inhalation (ISO) anesthetic protocols on selected ocular variables in captive black-tailed prairie dogs (Cynomys ludovicianus; BTPDs). ANIMALS 9 zoo-kept BTPDs. PROCEDURES The BTPDs received dexmedetomidine hydrochloride (0.25 mg/kg, IM), ketamine hydrochloride (40 mg/kg, IM), and midazolam hydrochloride (1.5 mg/kg, IM) or inhalation of isoflurane and oxygen in a randomized complete crossover design (2-day interval between anesthetic episodes). Pupil size, globe position, tear production, and intraocular pressure measurements were recorded at 5, 30, and 45 minutes after induction of anesthesia. For each BTPD, a phenol red thread test was performed in one randomly selected eye and a modified Schirmer tear test I was performed in the other eye. Intraocular pressure was measured by rebound tonometry. RESULTS Compared with findings for the DKM protocol, pupil size was smaller at all time points when the BTPDs underwent the ISO protocol. Globe position remained central during anesthesia with the DKM protocol, whereas it varied among central, ventromedial, and ventrolateral positions during anesthesia with the ISO protocol. Tear production and intraocular pressure decreased significantly over time when the BTPDs underwent either protocol. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ophthalmic examination findings for anesthetized BTPDs can be influenced by the anesthetic protocol used. The DKM protocol may result in more consistent pupil size and globe position, compared with that achieved by use of the ISO protocol. Tear production and intraocular pressure measurements should be conducted promptly after induction of anesthesia to avoid the effect of anesthetic episode duration on these variables.
显示更多 [+] 显示较少 [-]Comparison of 3 blind brachial plexus block techniques during maintenance of anesthesia and postoperative pain scores in dogs undergoing surgical procedures of the thoracic limb
2019
Skelding, A. | Valverde, A. | Aquilera, R. | Moens, N. M. | Sinclair, M. | Thomason, J. J.
The degree of analgesia provided by blind techniques for brachial plexus blocks (BPBs) has not been compared in clinical cases undergoing surgery of the thoracic limb. The objective of this study was to evaluate the anesthetic conditions and postoperative analgesia resulting from 3 different BPB local anesthetic techniques in canine patients undergoing such surgery. Twenty-four client-owned dogs received a standardized premedication/induction protocol (hydromorphone and acepromazine/propofol), maintained with isoflurane in oxygen using mechanical ventilation, in a prospective, randomized, blinded clinical trial. Before surgery, dogs received 1 of 3 anatomical BPB techniques: traditional, perpendicular, or axillary, with 0.2 mL/kg body weight (BW) of bupivacaine 0.5%. Cardiorespiratory variables and isoflurane end-tidal concentrations were recorded throughout anesthesia. Scores for anesthetic maintenance (0-best to 4-responsive), recovery quality (0-not responsive to 3-responsive), and Glasgow pain scale were recorded for up to 24 h postoperatively. All dogs recovered uneventfully from anesthesia and no differences in the measured variables or scores were noted among groups, during and after anesthesia. When thoracic limb amputations in each of the 3 groups (n = 9; 4 in traditional, 3 in perpendicular, 2 in axillary) were compared to the other surgical procedures (n = 15); however, scores for anesthetic maintenance were higher [0 (0 to 1) versus 0 (0 to 0); median (interquartile range)], recovery [1 (0 to 2) versus 0 (0 to 0)], and pain [2.4 (2.4 to 3.0) versus 1.6 (1.4 to 2.2)] in the first 3 h post-extubation. Surgery times were also longer with amputations [115 min (100 to 138 min) versus 50 min (41 to 90 min)]. The 3 BPB techniques provided similar anesthesia and postoperative pain scores. Despite higher pain scores in thoracic limb amputations than in less invasive surgeries, the BPB appeared to provide significant comfort.
显示更多 [+] 显示较少 [-]Effect of oral administration of gabapentin on the minimum alveolar concentration of isoflurane in dogs
2019
Johnson, Brittney A. | Aarnes, Turni K. | Wanstrath, Audrey W. | Pereira, Carolina H Ricco | Bednarski, Richard M. | Lerche, Phillip | McLoughlin, Mary M.
OBJECTIVE To determine the effect of oral administration of gabapentin (20 mg/kg) on the minimum alveolar concentration (MAC) of isoflurane in dogs. ANIMALS 6 healthy adult dogs (3 males and 3 females with a mean ± SD body weight of 24.8 ± 1.3 kg). PROCEDURES Each dog was anesthetized twice. Dogs were initially assigned to 1 of 2 treatments (gabapentin [20 mg/kg, PO] followed 2 hours later by anesthesia maintained with isoflurane or anesthesia maintained with isoflurane alone). A minimum of 7 days later, dogs received the other treatment. The MAC of isoflurane was determined by use of an iterative bracketing technique with stimulating electrodes placed in the maxillary buccal mucosa. Hemodynamic variables and vital parameters were recorded at the lowest end-tidal isoflurane concentration at which dogs did not respond to the stimulus. Effect of treatment on outcome variables was analyzed by use of a paired t test. RESULTS Mean ± SD MAC of isoflurane was significantly lower when dogs received gabapentin and isoflurane (0.71 ± 0.12%) than when dogs received isoflurane alone (0.91 ± 0.26%). Mean reduction in MAC of isoflurane was 20 ± 14%. Hemodynamic variables did not differ significantly between treatments. Mean time to extubation was significantly less when dogs received gabapentin and isoflurane (6 ± 4 minutes) than when dogs received isoflurane alone (23 ± 15 minutes). CONCLUSIONS AND CLINICAL RELEVANCE Oral administration of gabapentin 2 hours before anesthesia maintained with isoflurane had a MAC-sparing effect with no effect on hemodynamic variables or vital parameters of dogs.
显示更多 [+] 显示较少 [-]Comparison of intramuscular administration of alfaxalone-ketamine-dexmedetomidine and alfaxalone-butorphanol-midazolam in naked mole-rats (Heterocephalus glaber)
2019
Eshar, David | Huckins, Gail L. | Shrader, Trenton C. | Beaufrere, Hugues
OBJECTIVE To compare anesthetic effects of alfaxalone-ketamine-dexmedetomidine (AKD) and alfaxalone-butorphanol-midazolam (ABM) in naked mole-rats (Heterocephalus glaber). ANIMALS 20 naked mole-rats. PROCEDURES Naked mole-rats received AKD (alfaxalone, 2 mg/kg; ketamine, 20 mg/kg; and dexmedetomidine, 0.02 mg/kg; n = 10) or ABM (alfaxalone, 2 mg/kg; butorphanol, 2 mg/kg; and midazolam, 1 mg/kg; 9) IM; 1 animal was removed from the study. Atipamezole (I mg/kg) and flumazenil (0.1 mg/kg) were administered 40 minutes after anesthetic induction (defined as loss of the righting reflex) with AKD and ABM, respectively. Heart rate, respiratory rate, oxygen saturation, and reflexes were recorded every 5 minutes. RESULTS The ABM group had significantly longer median times for induction and recovery than the AKD group. Administration of ABM resulted in significantly lower respiratory rates than administration of AKD from time of anesthetic induction to 10 minutes after induction. Respiratory rate significantly decreased in the AKD group from I0 minutes after induction through the end of the anesthetic period but did not change over time in the ABM group. Males had higher respiratory rates in both groups. Loss of the righting reflex was still evident 40 minutes after induction in both groups. In the AKD group, all tested reflexes were absent from I0 to 40 minutes after induction; the ABM group had variable reflexes that recovered within individual animals over time. CONCLUSIONS AND CLINICAL RELEVANCE Both AKD and ABM provided effective immobilization in naked mole-rats, but AKD appeared to provide more consistent and deeper anesthesia, compared with administration of ABM.
显示更多 [+] 显示较少 [-]Evaluation of atipamezole as a treatment for dexmedetomidine-induced cardiovascular depression in anesthetized cats
2019
Zatroch, Kathryn K. | Sakai, Daniel M. | Parry, Stephen | Campoy, Luis | Martin-Flores, Manuel
OBJECTIVE To evaluate the cardiovascular effects of atipamezole administered at half the volume or the same volume as dexmedetomidine to isoflurane-anesthetized cats. ANIMALS 6 adult (1 to 2 years old) domestic shorthair cats (body weight, 3 to 6 kg). PROCEDURES Each cat was anesthetized with isoflurane and rocuronium 3 times; there was a 1-week washout period between successive anesthetic procedures. For each anesthetic procedure, dexmedetomidine (5 μg/kg) was administered IV. Five minutes after dexmedetomidine was administered, atipamezole (25 or 50 μg/kg) or saline (0.9% NaCl) solution was administered IM. Pulse rate, mean arterial blood pressure (MAP), cardiac output (CO), and systemic vascular resistance (SVR) were measured during anesthesia before dexmedetomidine administration (baseline), after dexmedetomidine administration, and 15, 30, 60, and 120 minutes after administration of atipamezole or saline solution. Pulse rate and MAP were also recorded when MAP was at its lowest value. Hemodynamic variables were compared among treatments at baseline, after dexmedetomidine administration, and after administration of atipamezole or saline solution. Effects of treatment and time on all variables were assessed with mixed-effects models. RESULTS Both doses of atipamezole resulted in a significantly lower MAP than did saline solution. Pulse rate, CO, and SVR were not significantly different among treatments after atipamezole or saline solution were administered. CONCLUSIONS AND CLINICAL RELEVANCE Atipamezole administered IM at half the volume or the same volume as dexmedetomidine was ineffective at increasing pulse rate or CO in anesthetized cats that received dexmedetomidine. However, atipamezole caused short-lasting but severe arterial hypotension.
显示更多 [+] 显示较少 [-]Effects of an enrofloxacin–silver sulfadiazine emulsion in the ears of rabbits with perforated tympanic membranes
2019
Bateman, Fiona L. | Kirejczyk, Shannon G. M. | Stewart, Georgina V. | Cutler, Daniel C. | Quilling, Laura L. | Howerth, Elizabeth W. | Mayer, Joerg
OBJECTIVE To determine whether an enrofloxacin–silver sulfadiazine emulsion (ESS) labeled for treatment of otitis externa in dogs has ototoxic effects in rabbits following myringotomy. ANIMALS 6 healthy adult New Zealand White rabbits. PROCEDURES Rabbits were anesthetized for brainstem auditory-evoked response (BAER) tests on day 0. Myringotomy was performed, and BAER testing was repeated. Saline (0.9% NaCl) solution and ESS were then instilled in the left and right middle ears, respectively, and BAER testing was repeated prior to recovery of rabbits from anesthesia. Application of assigned treatments was continued every 12 hours for 7 days, and rabbits were anesthetized for BAER testing on day 8. Rabbits were euthanized, and samples were collected for histologic (6 ears/treatment) and scanning electron microscopic (1 ear/treatment) examination. RESULTS Most hearing thresholds (11/12 ears) were subjectively increased after myringotomy, with BAER measurements ranging from 30 to 85 dB in both ears. All day 8 hearing thresholds exceeded baseline (premyringotomy) values; results ranged from 30 to 85 dB and 80 to > 95 dB (the upper test limit) in saline solution–treated and ESS-treated ears, respectively. All ESS-treated ears had heterophilic otitis externa, epithelial hyperplasia of the external ear canal, various degrees of mucoperiosteal edema, and periosteal new bone formation on histologic examination. Scanning electron microscopy revealed that most outer hair cells in the ESS-treated ear lacked stereocilia or were absent. CONCLUSIONS AND CLINICAL RELEVANCE Results supported that ESS has ototoxic effects in the middle ear of rabbits. Further research is needed to confirm these findings. Myringotomized laboratory rabbits may be useful to study ototoxicity of drugs used in human medicine.
显示更多 [+] 显示较少 [-]Comparison of intravenous anesthetic induction doses and physiologic effects of ketamine or alfaxalone in goats undergoing surgery with isoflurane anesthesia
2019
Oakleaf, Morgan H. | Mama, Khursheed R. | Mangin, Lisa M. | Lebsock, Kimberly J. | Bisazza, Kaatie T. | Hess, Ann M. | Easley, Jeremiah T.
OBJECTIVE To compare IV doses of alfaxalone and ketamine needed to facilitate orotracheal intubation and assess effects of each treatment on selected physiologic variables in goats undergoing orthopedic surgery with isoflurane anesthesia. ANIMALS 18 healthy adult goats. PROCEDURES Behavior was assessed before and after sedation with midazolam (0.1 mg/kg, IV) for IV catheter placement. Anesthesia was induced with additional midazolam (0.1 mg/kg, IV) and alfaxalone (n = 9) or ketamine (9) at 2 mg/kg, IV, over 30 seconds. An additional dose of alfaxalone or ketamine (1 mg/kg) was given IV if needed for intubation; anesthesia was maintained with isoflurane in oxygen and IV fluids with ketamine (0.5 to 1 mg/kg/h). Direct systolic (SAP), diastolic (DAP), and mean (MAP) arterial blood pressures; heart rate; and respiratory rate were recorded before induction, immediately after intubation, and during surgery. Qualitative anesthetic induction and recovery characteristics were assessed. Variables were compared within and between groups by statistical methods. RESULTS No preinduction variables differed significantly between groups. Postintubation and 30-minute intraoperative SAP, DAP, and MAP were higher for the ketamine group than for the alfaxalone group; within the alfaxalone group, postintubation SAP, MAP, and respiratory rate prior to mechanical ventilation were lower than respective preinduction values. All alfaxalone-group goats were intubated after 1 dose of the induction agent; 5 of 9 ketamine-group goats required an additional (1-mg/kg) dose. Postoperative recovery was good to excellent for all animals. CONCLUSIONS AND CLINICAL RELEVANCE Both drugs were suitable for induction of anesthesia after sedation with midazolam, but most goats required higher doses of ketamine to allow intubation. For situations in which alfaxalone administration is appropriate, the potential for decreased arterial blood pressures and respiratory rate should be considered.
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