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

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.     

The extradural pressure profile in goats following extradural injection

ObjectiveTo measure the extradural pressures in goats before and after extradural injection, and to investigate the occurrence of extradural pressure waves.Study designProspective experimental trial.AnimalsNine healthy adult goats weighing 59.4 ± 6.4 kg, scheduled for stifle arthroscopy.MethodsThe goats were pre–medicated with midazolam and anaesthesia was induced with propofol and maintained with sevoflurane. The goats were placed in lateral recumbency and extradural puncture was performed via the lumbosacral space. Correct placement of the needle was assessed by lack of resistance to the injection of saline. The needle was connected to an electronic pressure transducer to record extradural pressure. Measurements were taken before and after extradural injection of methadone (0.1 mg kg^?1, diluted to a total volume of 0.2 mL kg^?1) and 10 minutes later. Contrast medium was injected and correct extradural needle placement confirmed by radiography.ResultsLack of resistance to injection of saline occurred in all goats, but there were no pressure waves observed before injection in any animal. Radiography indicated incorrect needle placement in four animals and one had pressure waves synchronous with the arterial pulse after methadone injection. Correct needle placement was confirmed in the remaining five animals which exhibited pressure waves after extradural methadone injection. In the five goats with successful needle placement the baseline extradural pressure ranged from 0.4 to 2.5 kPa (3–19 mmHg), increasing to 4.4–39.9 kPa (33–300 mmHg) after injection. Ten minutes after injection, extradural pressure remained elevated and ranged from 2.5 to 17.3 kPa (19–130 mmHg).Conclusions and clinical relevanceExtradural pressure waves were not useful to confirm correct extradural needle placement in laterally recumbent goats. The presence of such waves after injection of 0.2 mL kg^?1 may be indicative of correct placement but even here we saw one of nine animals with extradural pressure waves where we failed to confirm correct needle placement. Extradural pressure increases after extradural injection.     

Tramadol improved the efficacy of ketamine–xylazine anaesthesia in young pigs

ObjectiveTo evaluate the influence of premedication with tramadol on xylazine–ketamine anaesthesia in young pigs.Study designProspective, randomized, blinded cross-over study.AnimalsTen young Niger hybrid pigs: mean weight 6.1 ± 0.6 kg.MethodsPigs were anaesthetized twice. Xylazine (2.5 mg kg^?1), ketamine (25 mg kg^?1) and atropine (0.04 mg kg^?1) were administered by intramuscular (IM) injection, 5 minutes after either tramadol (5 mg kg^?1)) (treatment XKT) or saline (treatment XKS). Time to loss of righting reflex (TLRR), duration of antinociception, duration of recumbency (DR) and recovery times (RCT) were recorded. Quality of induction of anaesthesia including ease of endotracheal intubation was assessed using a subjective ordinal rating score of 1 (worst) to 4 (best). Heart, pulse and respiratory rates, arterial oxygen saturations and rectal temperatures were determined over 60 minutes. Antinociception was assessed by the pigs’ response to artery forceps applied at the interdigital space. Data were compared with Student's t-test, Mann–Whitney's test or analysis of variance (anova) for repeated measures as appropriate and are presented as mean ± standard deviation.ResultsThe quality of anaesthetic induction was significantly better and duration of antinociception significantly longer (p < 0.05) in treatment XKT (3.1 ± 0.7 score; 43.7 ± 15.5 minutes) than in treatment XKS (2.8 ± 0.6 score; 32.0 ± 13.3 minutes). TLRR, DR and RCT did not differ significantly (p > 0.05) between treatment XKT (2.1 ± 0.8, 65.8 ± 17.0 and 13.2 ± 6.7 minutes) and treatment XKS (2.1 ± 1.3, 58.0 ± 14.8 and 10.3 ± 5.6 minutes). Physiological measurements did not differ between the treatments.Conclusion and clinical relevanceTramadol improved the quality of anaesthetic induction and increased the duration of antinociception in xylazine–ketamine anaesthetized young pigs without increasing duration of anaesthesia, nor causing additional depression of the physiological parameters measured.     

Anaesthetic and cardiorespiratory effects of romifidine/ketamine combinations in cats

ObjectiveTo study the anaesthetic and cardiorespiratory effects of intramuscular (IM) administration of different combinations of romifidine and ketamine in cats.Study designProspective, randomized, cross-over experiment.AnimalsSeven healthy adult cats weighing (mean ± SD) 3.4 ± 0.7 kg and aged 4.6 ± 3.2 years.MethodsAnimals received romifidine 100 μg kg^?1 with ketamine 7.5 (R100/K7.5) and 10 mg kg^?1 (R100/K10), romifidine 200 μg kg^?1 with ketamine 5 (R200/K5), 7.5 (R200/K7.5) and 10 mg kg^?1 (R200/K10) by IM injection. The time required to perform orotracheal intubation (IT) was measured and the ease of intubation assessed. The onset of anaesthesia (OA), duration of anaesthesia (DA) and anaesthesia recovery times (AR) were measured. Analgesia and muscle relaxation scores were recorded every 5 minutes for 60 minutes after OA. Heart rate, systolic arterial pressure, arterial haemoglobin saturation, respiratory rate, end-tidal carbon dioxide and oesophageal temperature were also measured.ResultsThe IT, OA and DA were not significantly different between the treatments. The analgesia and muscle relaxation scores were similar between all treatments at most time points. The cardiorespiratory variables were not significantly different between the treatments in most cases. The adverse effects were dose dependent and similar to those previously described for other combinations of α₂-agonists and ketamine.Conclusions and clinical relevanceAnaesthesia produced by the studied combinations of romifidine and ketamine may only be reliable when conducting brief and noninvasive procedures in cats. The OA times were slower and the DA shorter than those reported for other alpha-2 agonists combined with ketamine. A dose-related increase in the intensity of the anaesthetic effects could not be demonstrated in this study.     

Anaesthetic efficacy of eugenol on iridescent shark,Pangasius hypophthalmus (Sauvage, 1878) in different size classes

Anaesthetic efficacy of eugenol was investigated on iridescent shark, Pangasius hypophthalmus. Fish (2, 5, 10 and 20 g) subjected to 20–200 mg L^?1 eugenol and behavioural response as well as induction and recovery times were recorded. Induction and recovery times were significantly affected by eugenol concentration as well as fish weight (P < 0.05). Generally, 27–300 s after exposure to 20–200 mg L^?1 eugenol, iridescent sharks reached stage 3 anaesthesia (suitable for general handling). Fish entered stage 4 anaesthesia (suitable for surgery and blood sampling) over 54–710 s exposure to such concentrations. Recovery time was 109–600 s in all weight classes as well as eugenol concentrations. Mortality (44–100%) was only observed in 2 g fish when subjected to 110–170 mg L^?1 eugenol. This study, for the first time, showed behavioural response of iridescent shark to anaesthesia as well as effectiveness of eugenol as anaesthetic in this important aquaculture‐ornamental species. According to the models obtained in this study, minimum eugenol concentrations to induce anaesthesia over less than 3 min were 53.8–81.5 mg L^?1 in 2–20 g fish. Likewise, maximum eugenol concentrations in which fish recovered over less than 5 min were 65.9–105.8 mg L^?1 in 2–20 g fish.     

The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator

Objective

The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator.

What is the evidence? The issue of verifying correct needle position during epidural anaesthesia in dogs

Objectives

To review the methods for verifying the needle position while performing epidural anaesthesia in dogs, and to discuss the advantages, disadvantages, usefulness and reliability of each technique in the experimental and clinical research setting.