Effects of Ketamine on the Equine Electroencephalogram During Anesthesia With Halothane in Oxygen     

C.B. Johnson  BVSc  PhD  DVA  Diplomate ECVA  MRCA  MRCVS    M. Bloomfield  P.M. Taylor  MA  VetMB  PhD  DVA  Diplomate ECVA  MRCA  MRCVS 《Veterinary surgery : VS》1999,28(5):380-385

OBJECTIVE: To investigate the effects of ketamine on the electroencephalogram (EEG) of the horse. STUDY DESIGN: Prospective experimental study. ANIMALS: Eight Welsh mountain pony geldings weighing between 280 and 330 kg, 5 to 9 years old. METHODS: During halothane anesthesia at an end-tidal halothane concentration between 0.75 and 0.85%, the EEG frequency power spectrum and the auditory evoked potential were recorded while an infusion of ketamine was given. Ketamine 200 mg was infused over 5 minutes in 8 ponies. The effects of ketamine on the EEG were recorded continuously during the infusion and for a further 55 minutes. RESULTS: The ketamine infusion produced a plasma ketamine concentration that was significantly greater than the baseline until 7 minutes after the start of the infusion. The highest recorded ketamine concentration was 4.2+/-1.1 microg/ml recorded at 5 minutes after the start of the infusion. The spectral edge and median frequency of the EEG and the midlatency of the auditory evoked potential were compared with those recorded before the start of the infusion. The spectral edge, median frequencies and mid-latency of the auditory evoked potential were reduced by 21+/-13%, 31+/-20% and 19+/-36% respectively (mean +/- SD). Only the reduction in spectral edge frequency reached statistical significance. CONCLUSIONS: These results compared with those from other anesthetic and sedative agents suggest that the spectral edge frequency is an indicator of general central nervous system depression whereas the median frequency may be an indicator of antinociception.  相似文献   

Glomerular filtration rate after tramadol, parecoxib and pindolol following anaesthesia and analgesia in comparison with morphine in dogs     

Kavitha Kongara BVSc  MVSc  PhD    Paul Chambers BVSc  DVA  PhD  MRCVS  & Craig B Johnson BVSc  PhD  DVA  Dipl ECVA  MRCA  MRCVS 《Veterinary anaesthesia and analgesia》2009,36(1):86-94

ObjectiveTo compare the effects of morphine, parecoxib, tramadol and a combination of parecoxib, tramadol and pindolol on nociceptive thresholds in awake animals and their effect on glomerular filtration rate (GFR) in dogs subjected to 30 minutes of anesthesia.AnimalsEight adult mixed breed experimental dogs.Study designRandomized, controlled trial.MethodsDogs received 0.05 mg kg^?1 acepromazine subcutaneously (SC) as anaesthetic pre-medication. Thirty to sixty minutes later, they received either tramadol 3 mg kg^?1 intravenously, (IV), parecoxib (1 mg kg^?1 IV), a combination of tramadol 3 mg kg^?1 (IV), parecoxib 1 mg kg^?1 (IV) and pindolol 5 μg kg^?1 (SC), morphine (0.1 mg kg^?1 (IV) or 0.9% saline (2 mL). Anaesthesia was then induced with IV propofol to effect (2.9 ± 0.8 mg kg^?1) and maintained with halothane in oxygen for 30 minutes. Systolic arterial blood pressure was maintained above 90 mmHg with IV fluids and by adjusting the inspired halothane concentration. Post-treatment nociceptive thresholds to mechanical stimuli, expressed as percent of pre-treatment values, were compared between the treatments to assess the analgesic efficacy of the drugs. Plasma iohexol clearance (ICL), a measure of GFR, was estimated both before and 24 hours after induction of anaesthesia to study the drugs’ effects on renal perfusion. Nociceptive threshold and GFR data were compared using mixed model analysis in sas^®9.1.ResultsBoth tramadol and parecoxib produced similar analgesia, which was less than that of morphine. Their combination with pindolol produced analgesia comparable with morphine. None of the test drugs, either alone or in combination, reduced GFR.ConclusionTramadol and parecoxib (either alone or in combination) can increase nociceptive thresholds in awake dogs and have minimal effects on renal perfusion in normotensive dogs subjected to anaesthesia.  相似文献   

The effect of volatile anaesthetics on the relative sensitivity of facial and distal thoracic limb muscles to vecuronium in dogs     

Farshid Sarrafzadeh-Rezaei DVM  PhD  & R Eddie Clutton† BVSc  MRCVS  DVA  Diplomate ECVAA  MRCA 《Veterinary anaesthesia and analgesia》2009,36(1):55-62

ObjectiveTo compare n. facialis-m. nasolabialis (nF-mNL) and n. ulnar-mm. carpi flexorii (nU-mCF) sensitivity to vecuronium during halothane or isoflurane anaesthesia.Study designRandomized, prospective, experimental study.AnimalsForty-four client-owned dogs (19 male, 25 female) undergoing surgery; mean age: 5.0 years; mean body mass: 24.7 kg.MethodsThirty minutes after acepromazine (0.05 mg kg^?1) and morphine (0.5 mg kg^?1), anaesthesia was induced with intravenous (IV) thiopental and maintained with either halothane (n = 22) or isoflurane (randomly allocated) in oxygen. The lungs were mechanically ventilated and end-tidal inhaled anaesthetic (Fe’_IAA) maintained at 1.2 × MAC values. Neuromuscular transmission at nF-uNL and nU-mCF was monitored using the train of four count. Vecuronium (50 μg kg^?1 IV) was injected (t = 0) after 15 trains, 50-60 minutes after inhalational anaesthesia began, when Fe’_IAA had been constant for >15 minutes. Times of the disappearance (-) and reappearance (+) of the fourth (T4) and first twitch (T1) were recorded allowing the calculation of: latent (t = 0 to T4-) and manifest onset times (t = 0 to T1-) duration of blockade (T1- to T1+) and drug effect (T4- to T4+) and recovery time (T1+-T4+). Student’s paired t-test was used to compare simultaneous responses at nF-uNL and nU-mCF. An unpaired t-test was used to compare anaesthetic effects.ResultsLatent and manifest onset times were significantly (p < 0.05) briefer, blockade and drug effects were significantly longer and recovery from blockade were significantly slower in the nF-mNL unit in both halothane and isoflurane recipients. Profound block duration and drug action were significantly longer and recovery from blockade were significantly slower in halothane recipients at both nerve-muscle units.Conclusion and clinical relevanceThe nF-mNL was more sensitive than nU-mCF to vecuronium, particularly in halothane-anaesthetized dogs.  相似文献   

A comparison of the effects of two different doses of ketamine used for co-induction of anaesthesia with a target-controlled infusion of propofol in dogs   总被引：1，自引：0，他引：1  

Alastair R Mair BVM&S  Cert VA  MRCVS    Patricia Pawson BVMS  Diplomate ECVAA  PhD  MRCVS    Emily Courcier† BVetMed  BSc  MRCVS  & Derek Flaherty BVMS  Diplomate ECVAA  DVA  MRCA  MRCVS 《Veterinary anaesthesia and analgesia》2009,36(6):532-538

ObjectiveTo assess the cardiorespiratory and hypnotic-sparing effects of ketamine co-induction with target-controlled infusion of propofol in dogs.Study designProspective, randomized, blinded clinical study.AnimalsNinety healthy dogs (ASA grades I/II). Mean body mass 30.5 ± SD 8.6 kg and mean age 4.2 ± 2.6 years.MethodsAll dogs received pre-anaesthetic medication with acepromazine (0.03 mg kg^?1) and morphine (0.2 mg kg^?1) administered intramuscularly 30 minutes prior to induction of anaesthesia. Heart rate and respiratory rate were recorded prior to pre-medication. Animals were allocated into three different groups: Group 1 (control) received 0.9% NaCl, group 2, 0.25 mg kg^?1 ketamine and group 3, 0.5 mg kg^?1 ketamine, intravenously 1 minute prior to induction of anaesthesia, which was accomplished using a propofol target-controlled infusion system. The target propofol concentration was gradually increased until endotracheal intubation was possible and the target concentration at intubation was recorded. Heart rate, respiratory rate and noninvasive blood pressure were recorded immediately prior to induction, at successful intubation and at 3 and 5 minutes post-intubation. The quality of induction was graded according to the amount of muscle twitching and paddling observed. Data were analysed using a combination of chi-squared tests, Fisher's exact tests, Kruskal–Wallis, and anova with significance assumed at p< 0.05.ResultsThere were no significant differences between groups in the blood propofol targets required to achieve endotracheal intubation, nor with respect to heart rate, noninvasive blood pressure or quality of induction. Compared with the other groups, the incidence of post-induction apnoea was significantly higher in group 3, but despite this dogs in this group had higher respiratory rates overall.Conclusions and clinical relevanceUnder the conditions of this study, ketamine does not seem to be a useful agent for co-induction of anaesthesia with propofol in dogs.  相似文献   

A comparison of induction of anaesthesia using a target-controlled infusion device in dogs with propofol or a propofol and alfentanil admixture     

Adam Auckburally BVSc  CertVA  Diplomate ECVAA  MRCVS    Pat Pawson BVMS  PhD  Diplomate ECVAA  MRCVS  & Derek Flaherty BVMS  DVA  Diplomate ECVAA  MRCA  MRCVS 《Veterinary anaesthesia and analgesia》2008,35(4):319-325

ObjectiveTo compare induction targets, and the haemodynamic and respiratory effects, of propofol, or as an admixture with two different concentrations of alfentanil, delivered via a propofol target-controlled infusion (TCI) system.Study designProspective blinded randomized clinical study.Animals Sixty client-owned dogs scheduled for elective surgery under general anaesthesia. Mean body mass (SD) 28.5 kg (8.7) and mean age (SD) 3.5 years (2.4).MethodsDogs received pre-anaesthetic medication of acepromazine (0.03 mg kg⁻¹) and morphine (0.2 mg kg⁻¹) administered intramuscularly. Animals were randomly assigned to receive one of three induction protocols: propofol alone (group 1), a propofol/alfentanil (11.9 μg mL⁻¹) admixture (group 2), or a propofol/alfentanil (23.8 μg mL⁻¹) admixture (group 3), via a TCI system. Blood target concentrations were increased until endotracheal intubation was achieved, and induction targets were recorded. Heart rate (HR), respiratory rate (f_r) and non-invasive arterial blood pressure were recorded pre-induction, at endotracheal intubation (time 0) and at 3 and 5 minutes post-intubation (times 3 and 5, respectively). Data were analysed using anova for normally distributed data or Kruskal–Wallis test, with significance assumed at p < 0.05.ResultsThere were no significant differences between groups with respect to age, body mass, HR, f_r, systolic and diastolic blood pressure. The blood propofol targets to achieve endotracheal intubation were significantly higher in group 1 compared with groups 2 and 3. Mean arterial blood pressure (MAP) was significantly higher in group 1 at time 0 when compared with groups 2 and 3.Conclusions and clinical relevanceInduction of anaesthesia with a TCI system can be achieved at lower blood propofol targets when using a propofol/alfentanil admixture compared with using propofol alone. However, despite reduced targets with both propofol/alfentanil admixture groups, MAP was lower immediately following endotracheal intubation than when using propofol alone.  相似文献   

The post-tetanic count during vecuronium-induced neuromuscular blockade in halothane-anaesthetized dogs     

Farshid Sarrafzadeh-Rezaei DVM  DVSc  & R Eddie Clutton† BVSc  MRCVS  DVA  Diplomate ECVAA  MRCA 《Veterinary anaesthesia and analgesia》2009,36(3):246-254

ObjectiveTo evaluate the post‐tetanic count (PTC) for predicting the return of reversible neuromuscular blockade at the n. facialis–m. nasolabialis (nF–mNL) and n. ulnaris–mm. carpi flexorii (nU–mCF) nerve‐muscle units (NMUs) during profound vecuronium neuromuscular blockade in halothane‐anaesthetized dogs.Study designRandomized, prospective, experimental study.AnimalsTwenty‐five dogs (seven male 18 female) undergoing surgery; mean age: 4.8 years; mean body weight 22 kg.MethodsThirty minutes after acepromazine (0.05 mg kg^?1) and morphine (0.5 mg kg^?1) pre‐medication, anaesthesia was induced with intravenous (IV) thiopental and maintained with halothane, N₂O and O₂. The lungs were mechanically ventilated and end‐tidal halothane concentration (Fe′_HAL) maintained at 1.04%. Neuromuscular transmission was monitored using the train‐of‐four count (TOFC) at one nF–mNL and both nU–mCF units. Vecuronium (50 µg kg^?1 IV) was injected after 15 minutes constant Fe′_HAL. When the first twitch (T1) at both nU–mCF units had disappeared (t = 0) one (randomly allocated) ulnar nerve was stimulated every 5 minutes using PTC; TOF stimulation continued at the other sites. The PTC was plotted against the interval between recording time and T1's reappearance at the other NMUs.ResultsAt t = 0, the mean PTC in the contralateral nU–mCF unit was 18 (range 0–20). Mean PTC was a minimum at t = 5, rising to the maximum (20) at 25 minutes. Six dogs were vecuronium‐resistant as monitored by PTC. Excluding data from these revealed a strong negative relationship between ulnar PTC and the time taken for T1's return at the facial (r = ?0.7018; p < 0.00001) and contralateral ulnar (r = ?0.8409; p < 0.00001) NMUs.Conclusion and clinical relevancePost‐tetanic count monitoring beginning >5 minutes after the TOFC at nU–mCF = 0 provided a reliable estimate of T1's return at ulnar and facial NMUs.  相似文献   

Preliminary Investigations of Pain and Analgesia Assessment in Horses Administered Phenylbutazone or Placebo After Arthroscopic Surgery   总被引：1，自引：0，他引：1  

M. RAEKALLIO DVM  PhD    P.M. TAYLOR MA Vet MB  PhD  DVA  Diplomate ECVA  MRCA  MRCVS  R.C. BENNETT MA  VetMB  CertVA  MRCVS 《Veterinary surgery : VS》1997,26(2):150-155

Twenty-five horses undergoing arthroscopic surgery were studied to develop a schemeor assessing pain in horses while investigating the effects of phenylbutazone (PBZ) analgesia. Fifteen of the 25 horses received PBZ 4 mg/kg intravenously (IV) before surgery and 2 mg/kg (IV) every 12 hours thereafter until 60 hours; the remaining 10 (placebo group) were given a corresponding volume of saline. In both groups, venous blood samples were collected for catecholamine, β-endorphin, and Cortisol assays before premedication and up to 72 hours after surgery. Postoperative pain was evaluated by measuring predefined behavioral and physiological variables. A total postoperative pain severity index (TPPSI) was calculated using all variables. There were no differences between PBZ and placebo groups in plasma β-endorphin or catecholamine concentrations, but the TPPSI was higher in the placebo group than in the PBZ group, suggesting that perioperative treatment with PBZ has some analgesic benefit. This study shows the difficulties associated with pain assessment in horses.  相似文献