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Objective To determine biomarkers for impending fluid overload during intravenous fluid administration in a feline haemorrhage-resuscitation model. Study design Randomized crossover study. Animals A group of six domestic cats (mean age and weight: 21 months; 4.9 kg, respectively). Methods The cats underwent three treatments, 2 months apart. They were anaesthetized and instrumented to measure a range of physiological, blood gas, haematological and biochemical variables over time. Samples were taken during a health check, before haemorrhage, after haemorrhage and then at 30 minute intervals during fluid resuscitation and 24 hours later. The three treatments were: 1) control, sham haemorrhage and resuscitation; 2) lactated Ringer’s solution (LRS); and 3) 6% tetrastarch 130/0.4 (Vol) where the cats underwent a controlled haemorrhage then resuscitation by administering LRS and Vol at 60 and 20 mL kg–1 hour–1, respectively, for 120 minutes. Fluid overload was identified by nasal discharge and radiographic evidence. Biomarkers were variables that exceeded the reference interval for cats during treatment. Potential biomarkers were analysed using receiver operating characteristic curves (p Results Mean ± standard deviation total blood loss was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kg–1 for control, LRS and Vol, respectively. The total volume of LRS and Vol administered was 120 and 40 mL kg–1, respectively. Haematocrit, albumin, magnesium, chloride-to-sodium ratio and sodium-chloride difference were identified as potential biomarkers. These variables exceeded the reference intervals from 30 minutes of resuscitation onwards. A chloride-to-sodium ratio > 0.84 was the most sensitive (90%) and specific (75%) of all potential biomarkers. Conclusions and clinical relevance Changes in physiological variables, haematocrit and albumin were poor biomarkers of impending fluid overload compared with electrolytes. Finding the ideal biomarker to identify impending fluid overload of commonly used intravenous fluids should improve the safety of their administration in cats.

Morphine is the prototypical μ-opioid receptor agonist used to provide analgesia in veterinary species. Its effects are well-described in horses but not donkeys.To determine the antinociceptive effects of two doses of morphine in donkeys. To describe preliminary pharmacokinetic parameters of morphine in donkeys.In vivo experiment.Eight adult castrated male donkeys were given intravenous (IV) 0.9% saline, morphine 0.1 mg/kg bwt (LDM), or morphine 0.5 mg/kg bwt (HDM) in a randomised order with a minimum 1-week washout period. Mechanical nociceptive thresholds (MNTs) were determined by a blinded investigator pre-injection and 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 300, and 360 minutes post-injection. Venous blood samples were collected pre-injection and 2, 5, 10, 15, 30, 45, 60, 90, and 120 minutes post-injection. Data were analysed using Friedman's test with Dunn's post hoc test for multiple comparisons. Pharmacokinetic parameters were calculated for the HDM treatment.Baseline MNT was [median (interquartile range)] 8.9 (7.1-10.3) N and did not differ between treatments. Peak MNTs occurred at 60 minutes for both LDM (16.2 N) and HDM (25.0 N) treatments. MNTs after HDM treatment were higher than saline (p0.04) at 15, 60, 90, 120, 150, 180, 240, and 300 minutes post-injection. MNTs after LDM treatment were higher than baseline (p0.05) at 45 and 60 minutes post-injection. Terminal half-life for HDM was (mean ± SD) 51.0 ± 10.7 min, volume of distribution at steady-state 2.07 ± 0.33 L/min and clearance 49.2 ± 4.16 mL * min/kg using non-compartmental analysis. Concentration of morphine-3-glucuronide (M3G) was higher than morphine-6-glucuronide (M6G) at all sampled time points.Short duration of plasma sampling for pharmacokinetic analysis; lack of objective measure of gastrointestinal function.The HDM treatment provided mechanical antinociception in donkeys with no significant adverse effects. This article is protected by copyright. All rights reserved.

To assess the effect of two intravenous (IV) doses of lidocaine on the minimum anesthetic concentration (MAC) of isoflurane in chickens.Blinded, prospective, randomized, experimental crossover study.A total of six adult female chickens weighing 1.90 ± 0.15 kg.Chickens were anesthetized with isoflurane and mechanically ventilated. Isoflurane MAC values were determined (T0) in duplicate using an electrical noxious stimulus and the bracketing method. After MAC determination, a low dose (LD; 3 mg kgMAC of isoflurane (mean ± standard deviation) at T0 was 1.47 ± 0.18%. MAC at T1.5 and T3 was 1.32 ± 0.27% and 1.26 ± 0.09% (treatment LD); and 1.28 ± 0.06% and 1.30 ± 0.06% (treatment HD). There were no significant differences between treatments or times. Maximum plasma lidocaine concentrations at T3 were 496 ± 98 and 1200 ± 286 ng mLAdministration of lidocaine did not significantly change isoflurane MAC in chickens. Within treatments, plasma lidocaine concentrations were not significantly different at 1.5 and 3 hours.

Objective To evaluate the anesthetic and cardiopulmonary effects of xylazine–alfaxalone anesthesia in donkey foals undergoing field castration. Study design Prospective clinical study. Animals A group of seven standard donkeys aged [median (range)] 12 (10–26) weeks, weighing 47.3 (37.3–68.2) kg. Methods Donkeys were anesthetized with xylazine (1 mg kg−1) intravenously (IV) followed 3 minutes later by alfaxalone (1 mg kg−1) IV. Additional doses of xylazine (0.5 mg kg−1) and alfaxalone (0.5 mg kg−1) IV were administered as needed to maintain surgical anesthesia. Intranasal oxygen was supplemented at 3 L minute−1. Heart rate (HR), respiratory rate (fR) and mean arterial pressure (MAP) by oscillometry were recorded before drug administration and every 5 minutes after induction of anesthesia. Peripheral oxygen saturation (SpO2) was recorded every 5 minutes after induction. Time to recumbency after alfaxalone administration, time to anesthetic re-dose, time to first movement, sternal and standing after last anesthetic dose and surgery time were recorded. Induction and recovery quality were scored (1, very poor; 5, excellent). Results Median (range) induction score was 5 (1–5), and recovery score 4 (1–5). Overall, two donkeys were assigned a score of 1 (excitement) during induction or recovery. HR and MAP during the procedure did not differ from baseline. fR was decreased at 5 and 10 minutes but was not considered clinically significant. SpO2 was Conclusions and clinical relevance Xylazine–alfaxalone anesthesia resulted in adequate conditions for castration in 12 week old donkeys. While the majority of inductions and recoveries were good to excellent, significant excitement occurred in two animals and may limit the utility of this protocol for larger donkeys. Hypoxemia occurred despite intranasal oxygen supplementation.

The objective of this study was to describe the anatomy of the spinal nerves, specifically the last thoracic nerve (T13) and the first to third lumbar nerves (L1 to L3), in order to safely carry out an accurate proximal paravertebral block (PPVB) in sheep. This study consisted of 2 phases. In Phase 1, 7 sheep cadavers were dissected to identify the path and relevant anatomical landmarks of spinal nerves T13 and L1 to L3. In Phase 2, 2 healthy sheep received bilateral injections of 0.35 mL/kg body weight (BW) for each hemithoracolumbar area (0.088 mL/kg BW per nerve) of a dye-lidocaine solution (50:50) using a PPVB approach and then assessed for 15 min for signs of systemic and local effects of lidocaine. After euthanasia, the infiltrated area was dissected to assess the spread of the dye. Successful nerve staining (2 cm in length), macroscopic evidence of intraneural/intravascular injection, and spread to the epidural space and the abdominal cavity were recorded. In Phase 1, each branch of all nerves was easily identified and located using the caudal aspect of the spinous apophysis and the lateral edge of the transverse process of the respective vertebrae. An overlap was observed between the costoabdominal (T13), the iliohypogastric (L1), and ilioinguinal (L2) nerves. In Phase 2, all nerves were stained at least 2 cm from the injection site. There was no diffusion of the dye into the epidural space or abdominal cavity. In conclusion, using the anatomical landmarks described specifically for sheep, the PPVB provided accurate perineural distribution of the injected dye-lidocaine solution, which could result in clinical analgesia of the flank.L’objectif de cette étude était de décrire l’anatomie des nerfs rachidiens, en particulier le dernier nerf thoracique (T13) et les premier à troisième nerfs lombaires (L1 à L3), afin de réaliser en toute sécurité un bloc paravertébral proximal précis (PPVB) chez les moutons. Cette étude comportait deux phases. Dans la phase 1, sept cadavres de moutons ont été disséqués pour identifier le trajet et les repères anatomiques pertinents des nerfs rachidiens T13 et L1 à L3. Dans la phase 2, deux moutons en bonne santé ont reçu des injections bilatérales de 0,35 mL/kg de poids corporel (PC) pour chaque zone hémithoraco-lombaire (0,088 mL/kg de PC par nerf) d’une solution de colorant-lidocaïne (50:50) en utilisant une approche PPVB, puis évalué pendant 15 min pour des signes d’effets systémiques et locaux de la lidocaïne. Après l’euthanasie, la zone infiltrée a été disséquée pour évaluer la propagation du colorant. Une coloration nerveuse réussie (2 cm de longueur), une preuve macroscopique d’injection intraneurale/intravasculaire et une propagation à l’espace épidural et à la cavité abdominale ont été enregistrées. Dans la phase 1, chaque branche de tous les nerfs a été facilement identifiée et localisée en utilisant la face caudale de l’apophyse épineuse et le bord latéral de l’apophyse transverse des vertèbres respectives. Un chevauchement a été observé entre les nerfs costo-abdominal (T13), ilio-hypogastrique (L1) et ilio-inguinal (L2). Dans la phase 2, tous les nerfs ont été colorés à au moins 2 cm du site d’injection. Il n’y a pas eu de diffusion du colorant dans l’espace péridural ou la cavité abdominale. En conclusion, en utilisant les repères anatomiques décrits spécifiquement pour les moutons, le PPVB a fourni une distribution périneurale précise de la solution de colorant-lidocaïne injectée, ce qui pourrait entraîner une analgésie clinique du flanc.(Traduit par Docteur Serge Messier).

Objective To determine the effect of hyaluronidase on time to onset and offset of anaesthesia in ropivacaine or bupivacaine femoral–ischiatic nerve blocks. Study design Blinded randomized crossover trial. Animals Eight dogs. Methods Each dog underwent four treatments separated into two blocks – initially, the ropivacaine treatment block: RS (ropivacaine 0.5% plus saline 0.9%) and RH (ropivacaine 0.5% plus hyaluronidase 100 IU mL–1), followed 3 weeks later by the bupivacaine treatment block: BS (bupivacaine 0.5% plus saline) and BH (bupivacaine 0.5% plus hyaluronidase). The local anaesthetics were administered at 0.1 mL kg–1 per site. Hyaluronidase and saline were administered at 0.02 mL kg–1 per site. Performance of femoral–ischiatic blocks was aided by a combined ultrasound–electrolocation technique. The mechanical nociceptive threshold was measured, until offset or 360 minutes, using an algometer to ascertain baseline, onset and offset of anaesthesia. Onset and offset of anaesthesia were defined as a 25% increase above and as a return to Results The median (range) onset of anaesthesia for RS and RH was 21 (3–60) and 12 (3–21) minutes, respectively (p = 0.141), and offset was 270 (90–360) and 180 (30–300) minutes, respectively (p = 0.361). By contrast, the median (range) onset of anaesthesia for BS and BH was 24 (3–60) and 9 (3–27) minutes, respectively (p = 0.394), and offset was 360 (240–360) and 330 (210–360) minutes, respectively (p = 0.456). Conclusion and clinical relevance Hyaluronidase had no effect on the onset and offset times of ropivacaine and bupivacaine femoral–ischiatic nerve blocks in dogs compared with saline. The onset and offset times were highly variable in all treatments. Clinically, the high variability of the onset and offset times of the regional anaesthesia of these local anaesthetic drugs means that clinicians must monitor the animal’s response and, if required, provide additional analgesic drugs.

Simple Summary General anesthesia in small ruminants is still a challenge under field conditions. Propofol is an injectable short-acting anesthetic used to provide induction and/or anesthesia maintenance. Isoflurane is the inhaled anesthetic more widely used for providing general anesthesia; however, it requires an expensive equipment for its administration, and high doses may produce environmental pollution. Both anesthetics produce dose-related cardiovascular depressant effects. This study aimed to compare the effects of propofol or isoflurane, combined with a constant-rate infusion of fentanyl–lidocaine–ketamine (total [total intravenous anesthesia (TIVA)] and partial intravenous anesthesia [PIVA], respectively) in goats undergoing abomasotomy. Our results showed that both TIVA and PIVA protocols produced a satisfactory quality of anesthesia during surgery, with minimal changes in cardiopulmonary parameters. However, recovery from anesthesia induced by propofol fentanyl–lidocaine–ketamine might be of poor quality. Abstract This study aimed to compare, first, the anesthetic and cardiopulmonary effects of propofol or isoflurane anesthetic maintenance in goats receiving a fentanyl–lidocaine–ketamine infusion undergoing abomasotomy and, secondly, to compare the quality of the recovery from anesthesia. Two groups were used: propofol (TIVA) and isoflurane (PIVA). Goats were premedicated with fentanyl (10 μg/kg intravenously [IV]), lidocaine (2 mg/kg, IV), and ketamine (1.5 mg/kg, IV). Anesthesia was induced with propofol and maintenance consisted of fentanyl (10 μg/kg/h, IV), lidocaine (50 μg/kg/min, IV), and ketamine (50 μg/kg/min, IV) as constant-rate infusions (CRIs), combined with either CRI of propofol at initial dose of 0.3 mg/kg/min, IV (TIVA), or isoflurane with initial end-tidal (FE’Iso) concentration of 1.2% partial intravenous anesthesia (PIVA). The mean effective propofol dose for maintenance was 0.44 ± 0.07 mg/kg/min, while the mean FE’Iso was 0.81 ± 0.2%. Higher systolic arterial pressure (SAP) values were observed in total intravenous anesthesia (TIVA) during some time points. Recovery was smooth in PIVA, while restlessness, vocalizations, and paddling were observed in TIVA. Both protocols produced a satisfactory quality of anesthesia during surgery, with minimal impact on cardiopulmonary function. Nevertheless, recovery after anesthesia in TIVA might be of poor quality.

Objective To evaluate the oxygen reserve index (ORI) as a noninvasive estimate of the PaO2 during moderate hyperoxaemia [100–200 mmHg (13.3–26.6 kPa)], and to determine ORI values identifying PaO2 > 100, > 150 (20.0 kPa) and > 200 mmHg in anaesthetized donkeys with an inspired fraction of oxygen (F i O2) > 0.95. Study design Prospective observational study. Animals A group of 28 adult standard donkeys aged (mean ± standard deviation) 4 ± 2 years and weighing 135 ± 15 kg. Methods Donkeys were sedated intramuscularly with xylazine and butorphanol; anaesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen. An adhesive sensor probe was applied to the donkey’s tongue and connected to a Masimo pulse co-oximeter to determine ORI values. An arterial catheter was inserted into an auricular artery. After ORI signal stabilization, the value was noted and PaO2 determined by blood gas analysis. The Pearson correlation coefficient was used to assess the relationship between ORI and PaO2 for oxygen tension 150 and 200 mmHg (20.0 and 26.6 kPa) with the highest sensitivity and specificity. Results A total of 106 paired measurements were collected. A mild positive correlation was observed between ORI and PaO2 for values 0.0, > 0.1 and > 0.3 indicated a PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) with negative predictive values > 94%. Conclusions and clinical relevance ORI may provide a noninvasive indication of PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) in anaesthetized donkeys with an F i O2 > 0.95, although it does not replace blood gas analysis for assessment of oxygenation.

To describe acid-base status using the Henderson-Hasselbalch, Stewart and semi-quantitative methods of analysis in a feline haemorrhage-resuscitation model.Randomized crossover study.A total of six domestic cats (mean age, 21 months; weight, 4.9 kg).Venous blood samples were taken before haemorrhage, after haemorrhage at 30 minute intervals during fluid resuscitation and at 24 hours. The cats were anaesthetized and underwent following treatments: no purposeful haemorrhage and resuscitation (NoPHR), purposeful haemorrhage followed by either lactated Ringer's solution (LRS) or 6% tetrastarch 130/0.4 (Voluven) for resuscitation. LRS and Voluven were administered at 60 and 20 mL kgThe total blood loss at 120 minutes was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kgIn an experimental haemorrhage and resuscitation model in cats, blood pH was similar among treatments over time regardless of severe haemorrhage and resuscitation with LRS or Voluven or mild haemorrhage and no resuscitation.

Objective To determine the minimum infusion rate (MIR) of alfaxalone required to prevent purposeful movement in response to standardized stimulation while co-administered with lidocaine at three different doses by constant infusion rate infusion (CRI) in goats. Study design Prospective, blinded, randomized crossover, experimental. Animals A total of eight healthy goats: four does and four wethers. Methods Anaesthetic induction was with lidocaine at 1 mg kg−1 [low dose of lidocaine (L-Lid)], 2 mg kg−1 [moderate dose (M-Lid)] or 4 mg kg−1 [high dose (H-Lid)] and alfaxalone at 2 mg kg−1. Anaesthetic maintenance was with alfaxalone initially at 9.6 mg kg−1 hour−1 combined with one of three lidocaine treatments: 3 mg kg−1 hour−1 (L-Lid), 6 mg kg−1 hour−1 (M-Lid) or 12 mg kg−1 hour−1 (H-Lid). The MIR of alfaxalone was determined by testing for responses to a stimulation in the form of clamping on a digit with a Vulsellum forceps every 30 minutes during lidocaine CRI. Basic cardiopulmonary parameters were measured. Results The alfaxalone MIRs were 8.64 (6.72–10.56), 6.72 (6.72–8.64) and 6.72 (6.72–6.72) mg kg−1 hour−1 during L-Lid, M-Lid and H-Lid, respectively, without any significant differences among treatments. Compared to the initial rate of 9.6 mg kg−1 hour−1, these reductions in MIR are equivalent to 10, 30 and 30%, respectively. Significant increases in heart rate (HR) and arterial carbon dioxide partial pressure (PaCO2) and decreases in arterial haemoglobin saturation (SaO2), arterial oxygen partial pressure (PaO2) and respiratory frequency (fR) immediately after induction were observed during all lidocaine treatments. Conclusions and clinical relevance Lidocaine reduces the alfaxalone MIR by up to 30% with a tendency towards a plateauing in this effect at high CRIs. Immediate oxygen supplementation might be required to prevent hypoxaemia.