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The transversus abdominis plane (TAP) block is an ultrasound guided regional anaesthetic technique used to provide analgesia to the abdominal wall. Research in humans and cats has demonstrated that TAP blocks reduce pain and post-operative opioid requirements after abdominal surgery. To date TAP blocks have not been described in rats. The optimal technique to employ when performing TAP blocks is controversial with single point injection techniques failing to reliably provide adequate coverage of the cranial abdominal wall. It has been suggested that performing a two point injection may provide more reliable coverage of the cranial abdominal wall. The objective of this study was to determine the feasibility of performing ultrasound guided TAP blocks in rat cadavers and to evaluate whether performing a two point technique provides greater spread of injectate than a one point technique when administering the same total volume of methylene blue solution. Twenty-three, four-month-old, female Sprague Dawley rat cadavers weighing 506 ± 78 g were used. TAP blocks were performed using a total of 1 ml/kg of methylene blue solution. Overall success rates for injections were 21.7% (13.6–32.8%). Single point injection area of spread was 87.8 ± 32 mm2 compared with 102.4 ± 17 mm2 for the two point injection technique. Due to the low success rate the use of TAP blocks using the current technique cannot be recommended. Two point injection technique appears to provide greater spread; however, additional data is required to draw meaningful conclusions.

Este artículo se encuentra disponible en la siguiente URL: https://www.sciencedirect.com/science/article/abs/pii/S1467298721000611?via%3Dihub En este artículo de investigación también participan: Lisa Tarragona y Diego A. Portela. Este es el pre-print del siguiente artículo: Verdier, N., Martinez-Taboada, F., Otero, P. E., Redondo García, J. I., Zaccagnini, A. S., Costoya, A. A., Tarragona, L. & Portela, D. A. (2021). Evaluation of electrical nerve stimulation to confirm sacrococcygeal epidural needle placement in dogs. Veterinary Anaesthesia and Analgesia, vol. 48, i. 4 (jul.), pp. 612?616, que se ha publicado de forma definitiva en https://doi.org/10.1016/j.vaa.2020.12.008. This is the pre-peer reviewed version of the following article: Verdier, N., Martinez-Taboada, F., Otero, P. E., Redondo García, J. I., Zaccagnini, A. S., Costoya, A. A., Tarragona, L. & Portela, D. A. (2021). Evaluation of electrical nerve stimulation to confirm sacrococcygeal epidural needle placement in dogs. Veterinary Anaesthesia and Analgesia, vol. 48, i. 4 (jul.), pp. 612?616, which has been published in final form at https://doi.org/10.1016/j.vaa.2020.12.008. Objectives: To evaluate the use of 0.7 mA as a fixed electrical current to indicate epidural needle placement and to confirm that 0.7 mA is greater than the upper limit of the minimal electrical threshold (MET) for sacrococcygeal epidural needle placement in dogs. Study design: Prospective clinical study. Animals: A group of 20 client-owned dogs. Methods: During general anaesthesia and with standard monitoring, the presence of the 3patellar reflex was confirmed in all dogs. An insulated needle was inserted through the sacrococcygeal intervertebral junction and absence of tail movement was confirmed when a fixed electrical current of 0.7 mA was applied. Then, the needle was further advanced towards the epidural space until the expected motor response was obtained – the 'nerve stimulation test' (NST). The NST was considered positive when a motor response of the muscles of the tail was elicited but not the perineal muscles, whereas it was considered negative when no movement of the tail was evoked. The electrical current was turned to 0 mA and then increased by 0.01 mA increments until tail movement was evoked, this was recorded as the MET. In the positive NST cases, 0.05 mL cm-1 occipitococcygeal length of 2% lidocaine or 0.25-0.5% bupivacaine was administered. Epidural blockade was confirmed by the loss of patellar reflex. Descriptive statistics were used to present data. Results: Sacrococcygeal epidural needle placement, corroborated by loss of the patellar reflex, was correctly predicted in 89.5% (95% confidence interval: 68.6%-97.1%) of the cases. The MET was 0.22 mA (0.11-0.36). Conclusions and clinical relevance: A current of 0.7 mA is approximately twice the upper limit of the MET for epidural placement. Therefore, this study demonstrates, with a success rate of 89.5%, the adequacy of using 0.7 mA as the fixed electrical current to detect sacrococcygeal epidural needle placement in dogs. Preprint

Objectives This study aimed to describe the prominent landmarks for an in-plane ultrasound-guided lateral approach to an axillary RUMM block in cats and document the anatomical distribution of injected solution in cadavers. Methods Eleven mixed breed, frozen-thawed cat cadavers were used. The ultrasound probe was placed on the lateral aspect of the forelimb. A spinal needle was used to inject either methylene blue 5 mg/ml or permanent tissue dye 1:10 within the focal clustering point of the radial (R), ulna (U), median (M) and musculocutaneous (Mc) nerves. The block was approached from either a cranial or caudal direction. Specimens were immediately dissected. A successful block was defined as ⩾20 mm of continuous stain on all nerves (R, U, M and Mc), a partial block as one or more nerves stained ⩾20 mm continuously and a negative block failed to stain any nerve ⩾20 mm. Results The cranial approach stained the R 8/9, U 6/9, M 6/9 and Mc 8/9 nerves successfully, while the caudal approach stained the R 7/9, U 8/9, M 7/9 and Mc 5/9 nerves successfully. There were no statistical differences on staining rates between approaches or limbs used. Conclusions and relevance The lateral approach to an axillary RUMM block is feasible in cats and may be a useful alternative to current approaches used for brachial and antebrachial desensitisation. Both cranial and caudal approaches produced similar results; however, further research in live animals will determine the clinical applicability.

PICO question In dogs with osteoarthritis how effective is treatment with tramadol in reducing the severity of the clinical signs associated with pain when compared to no treatment? Clinical bottom line Category of research question Treatment The number and type of study designs reviewed Two papers were critically reviewed. There was one randomised crossover controlled trial and one non-randomised controlled trial Strength of evidence Strong Outcomes reported Budsberg et al. (2018) found no significant differences in the objective gait analyses (vertical ground reaction forces, and peak vertical force) between baseline and end of treatment, between tramadol and placebo. Similarly, there was no significant difference in the proportion of dogs with positive response based on the subjective Canine Brief Pain Inventory questionnaire (CBPI) between tramadol and placebo. The positive control of carprofen yielded significant differences to both placebo and tramadol in all outcomes measured. Malek et al. (2012) found no significant differences in the objective outcomes measured (gait analyses, and total daily activity) between tramadol and placebo. There were significant improvements in the subjective CBPI (total score, pain severity and pain interference score) between the baseline and end of treatment, within the tramadol group. However, there was no significant difference in the percentage change of the total score, pain severity or pain interference score between all treatment groups including tramadol and placebo Conclusion In dogs with osteoarthritis, the use of tramadol alone did not demonstrate any significant analgesic effects How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Objectives The aim of this study was to compare four inflation techniques on endotracheal tube cuff (ETC) pressure using a feline airway simulator. Methods Ten participants used four different endotracheal cuff inflation techniques to inflate the cuff of a low-pressure, high-volume endotracheal tube within a feline airway simulator. The simulator replicated an average-sized feline trachea, intubated with a 4.5 mm endotracheal tube, connected to a circle breathing system and pressure-controlled ventilation with oxygen and medical air. Participants inflated the ETC: by pilot balloon palpation (P); by instilling the minimum occlusive volume (MOV) required for loss of airway leaks during mechanical ventilation; until a passive release of pressure with use of a loss-of-resistance syringe (LOR); and with use of a syringe with a digital pressure reader (D) specifically designed for endotracheal cuff inflation. Intracuff pressure was measured by a manometer obscured to participants. The ideal pressure was considered to be between 20 and 30 cmH2O. Data were analysed by Shapiro–Wilk, Kruskal–Wallis and χ2 tests, as appropriate. Results Participants were eight veterinarians and two veterinary nurses with additional training in anaesthesia. Measured median intracuff pressures for P, MOV, LOR and D, respectively, were 25 cmH2O (range 4–74 cmH2O), 41 cmH2O (range 4–70 cmH2O), 31 cmH2O (range 18–64 cmH2O) and 22 cmH2O (range 20–30 cmH2O). D performed significantly better ( P Conclusions and relevance Use of D for cuff inflation achieved optimal cuff pressures. There may be high operator-dependent variability in the cuff pressures achieved with the use of P, MOV or LOR inflation techniques. As such, a cuff manometer is recommended when using any of these techniques.

Objective To compare the cranial spread of epidural injectates between lumbosacral (LS) and sacrococcygeal (SCo) approaches in order to guide volume selection for SCo epidural anaesthesia in the dog. Study design Prospective, randomized cadaveric experimental study. Animal A group of 13 adult greyhound cadavers. Methods The greyhound cadavers were randomly allocated to receive an epidural injection of diluted contrast via the LS or SCo approach. Incremental volumes (0.1, 0.2, 0.4 and 0.6 mL kg–1) were injected consecutively, and a computed tomography (CT) scan was completed following every volume increment. Cranial spread of contrast was recorded by counting the number of vertebrae cranial to the LS space that the injectate had reached, expressed as a vertebral value (n). This vertebral value was measured taking into consideration the percentage of the cord surrounded by contrast (vertebral canal coverage, %). Results The cranial spread of contrast was similar at 0.1 mL kg–1 [1 (0–3) versus 2 (1–3) n], 0.2 mL kg–1 [3 (0–10) versus 3 (1–5) n], 0.4 mL kg–1 [12 (9–18) versus 11 (3–19) n] and 0.6 mL kg–1 [18 (12–20) versus 15 (10–23) n] for the LS and SCo injections, respectively (p = 0.945). There was a significant interaction between the volume injected and vertebral canal coverage (p Conclusions and clinical relevance The cranial spread of contrast was similar, independent of whether the epidural injection was performed in the LS or SCo intervertebral space. Current volume guidelines used for the LS approach may produce similar distribution patterns when the SCo approach is used. Further studies are required in order to evaluate the in vivo effectiveness and the adequacy in differently sized dogs of the results found herein.

Alfaxalone is a neurosteroid anesthestic drug. In 2001, alfaxalone (Alfaxan) was released and since then there have been reports of it use in a large spectrum of veterinary species, including some avian species. Alfaxalone's rapid onset, short duration of action and multiple routes of administration (intravenous, intramuscular, subcutaneous, and intraosseos) make it a versatile induction agent. The following case report describes the use of intravenous alfaxalone in two pet domestic chickens (Gallus gallus domesticus). Alfaxalone was administered intravenously to effect. The quality of induction in both cases were poor, with a period of excitement occurring after administration of 5 mg/kg, before muscle relaxation following continued administration to a total dose of 10 mg/kg in the first case and 15 mg/kg for the second case.

OBJECTIVE To evaluate 3 doses of gadoxetic acid (Gd-EOB-DPTA) for hepatic CT and cholangiography in cats and to determine optimal timing for hepatobiliary image acquisition and evaluation of the contrast-enhanced hepatobiliary anatomy. ANIMALS 6 healthy cats. PROCEDURES Cats were anesthetized; sequential CT scans were performed 0, 5, 25, 45, 65, and 85 minutes after IV administration of Gd-EOB-DTPA at low (0.0125 mmol/kg), medium (0.1 mmol/kg), and high (0.3 mmol/kg) doses. Hepatobiliary enhancement for each dose was objectively assessed over time and by use of a subjective semiquantitative visual assessment score. RESULTS No contrast-related adverse effects were detected. Each increase in dose of contrast medium resulted in a significant increase in HU across the hepatobiliary system. The liver had a significantly higher number of HU at 45 minutes, with homogenous enhancement at all doses of contrast medium. Contrast-enhanced cystic and bile duct HU were significantly higher and maximal at 65 minutes. Contrast-enhanced gallbladder HU did not plateau by 85 minutes. At a high dose of contrast medium, 12 of 60 (20%) biliary tract scores indicated no enhancement, 34 (57%) indicated poor enhancement, and 14 (23%) indicated moderate enhancement. No cat had excellent enhancement of the biliary tract at any dose. CONCLUSIONS AND CLINICAL RELEVANCE Gd-EOB-DTPA–enhanced hepatic CT and cholangiography in cats were safely performed and provided good hepatic enhancement but poor to moderate enhancement of the biliary tract. This technique may be useful for assessing the liver parenchyma in cats, but its value for assessing the biliary tract is questionable.

The aim was to evaluate if medetomidine and dexmedetomidine affected arterial ovarian blood flow in dogs. The dogs were randomly assigned to two different groups. In Group 1, medetomidine (10 µg/kg) was administered intramuscularly and, in Group 2, dexmedetomidine (5 µg/kg) was used. After a preliminary exam, arterial blood pressure (BP) was measured and a duplex Doppler ultrasonographic examination of both ovarian arteries was performed. Twenty minutes after the administration of medetomidine or dexmedetomidine, BP and ovarian Doppler ultrasonography were repeated. High quality tracings of ovarian artery flow velocity were obtained in all dogs and Doppler parameters: Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV) and Resistive Index (RI) were measured before and after drug administration in the left (LO) and right (RO) ovaries. PSV and EDV values decreased significantly after drug administration (p &lt, 0.05) compared to the non-sedated values, but no differences were found between the LO and RO (p &gt, 0.05). The RI was not affected by drugs administration in neither of the groups studied (p &gt, 0.05). In conclusion, the administration of medetomidine or dexmedetomidine causes a decrease in blood flow velocity in the ovarian artery and may be a good choice to avoid excessive bleeding prior surgeries in which ovariectomy.

OBJECTIVE: To determine whether the surgeon can influence the accuracy of milling during the TATE elbow arthroplasty by applying force to the milling arm during the milling procedure. STUDY DESIGN: In vitro study on Sawbone specimens. SAMPLE POPULATION: Thirty identical solid foam models of the canine right humerus, elbow joint, and antebrachium (size large). METHODS: TATE elbow arthroplasty was performed on 30 elbows equally divided into 3 types of forces applied to the milling arm: (1) no force, (2) a maximally converging force, and (3) a maximally diverging force using the center of rotation post as a reference point. The resulting component‐bone interface and post fit were quantified with digital photography. RESULTS: The component‐bone interface gap differed between techniques for most angles. The application of convergent or divergent milling forces frequently increased the component‐bone interface gap. Post fit was also influenced by the milling technique, application of a convergent or divergent milling force affecting the fit of multiple posts. Interface gaps tended to be greater on the lateral aspect, an area that is not visible to the surgeon intraoperatively. CONCLUSION: In this bone model study, application of convergent or divergent forces during milling frequently resulted in greater component‐bone interface gaps and poorer post fit than when a neutral position was maintained. CLINICAL SIGNIFICANCE: Surgeons may affect implant fit within the constraints of the current arthroplasty system if they do not maintain a neutral position during milling. Greater component‐bone interface gaps and poorer post fit may affect component osseointegration and lead to aseptic implant loosening.

Objective To compare the dose, cardiopulmonary effects and quality of anaesthetic induction in dogs using propofol (10 mg mL–1) and diluted propofol (5 mg mL–1). Study design Randomized, blinded, clinical study. Animals A total of 28 client-owned dogs (12 males/16 females). Methods Following intramuscular acepromazine (0.02 mg kg–1) and methadone (0.2 mg kg–1), propofol (UP, 10 mg mL–1) or diluted propofol (DP, 5 mg mL–1) was administered intravenously (0.2 mL kg–1 minute–1) by an anaesthetist unaware of the allocated group to achieve tracheal intubation. Sedation, intubation and induction quality were scored from 0 to 3. Pre- and post-induction pulse rate (PR), respiratory rate (fR) and systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressure were compared. Time to first breath and induction dose were recorded. Data were analysed for normality and Mann–Whitney U or Student t tests were performed where appropriate. Significance was set at p Results The propofol dose administered to achieve induction was lower in the DP group (2.62 ± 0.48 mg kg–1) than in the UP group (3.48 ± 1.17 mg kg–1) (p = 0.021). No difference was observed in pre- and post-induction PR, SAP, MAP, DAP and fR between groups. The differences between post-induction and pre-induction values of these variables were also similar between groups. Time to first breath did not differ between groups. Sedation scores were similar between groups. Quality of tracheal intubation was marginally better with UP 0 (0–1) than with DP 1 (0–2) (p = 0.036), but overall quality of induction was similar between groups [UP 0 (0–1) and DP 0 (0–1), p = 0.549]. Conclusion and clinical relevance Diluting propofol reduced the dose to induce anaesthesia without significantly altering the cardiopulmonary variables.

One-lung ventilation (OLV) is an anaesthetic technique utilised for improved visualisation and access of the surgical field during thoracoscopy. The authors present two cases that underwent OLV with use of a double lumen tube (DLT). The first case was intubated with endoscopic guidance for bronchial port intubation of the right mainstem bronchus. This dog experienced prolonged periods of intraoperative hypoxemia. Upon case review, it was suspected intubation of the mainstem bronchus resulted in occlusion of the right cranial lung lobe. In the second case, the DLT was placed bronchoscopically into the left mainstem bronchus with the aid of computed tomography (CT). Excellent intraoperative oxygenation was achieved. When DLTs are used in dogs, their anatomical differences from humans make them susceptible to additional lung occlusion and pulmonary shunting. Computed tomography is recommended as a fundamental addition to bronchoscopy for correct tube placement.Keywords: Anaesthesia, Double lumen tube, One-lung ventilation, Thoracoscopy.

To investigate the accuracy of visual blood loss estimation from small animals among veterinary staff and final-year veterinary students, and the development and utility of a pictorial guide to improve estimation, in a veterinary hospital.Online anonymous voluntary survey.A two-part online survey was circulated to voluntary participants at the University Veterinary Teaching Hospital Sydney, The University of Sydney, including students, nurses, interns, residents, general practitioners and specialists. The survey consisted of visual and brief descriptive depictions of blood loss scenarios involving small animals, principally including images of common surgical items and receptacles containing a bloodlike substance. Each participant estimated the blood volume (in millilitres) for each scenario two times, initially [Pre-Guide (PGD)] and then with the aid of a pictorial guide [With-Guide (WGD)]. The pictorial guide used similar images labelled with corresponding volumes. Data were analysed for normality with the Shapiro-Wilk test, corrected to absolute error and compared for statistical significance using the Wilcoxon signed-rank test or the Kruskal-Wallis test as appropriate (p0.05).A total of 59 participants provided 288 responses. The raw median PGD error was -16 mL (range -105 to 443 mL), indicating a tendency towards underestimation of the actual volume. The WGD median error was 18 mL (range -91 to 191 mL), indicating a tendency towards overestimation when using a pictorial guide (p0.0001). Data corrected to absolute error showed a PGD median error of 34 mL (range 0-443 mL) and WGD median error of 23 mL (range 0-191 mL; p0.0001). There were differences between the participant roles in the PGD phase but not when using the pictorial guide.and clinical relevance Participants generally underestimated surgical blood loss, with a wide variation, when visually estimating scenarios involving small animals. A pictorial guide improved estimation by reducing the absolute median error and narrowing the range.

Objectives The aim of this study was to describe the technique for a novel lateral approach to femoral nerve block in cat cadavers. Methods Five feline cadavers were used in our prospective cadaveric experimental study. Ultrasonography was used to identify the anatomy injection site. Both pelvic limbs were injected with a volume (0.1 ml/kg) of methylene blue in each cat. The cadavers were placed in lateral recumbency, with the limb to be blocked positioned uppermost. The transducer was held perpendicular to the most proximal area of the pelvic limb, ventral to the greater trochanter and slightly cranial to the femur. Methylene blue was injected after the localisation of the femoral nerve. Immediately after the injection, the cat was turned and the technique was repeated on the contralateral side. After performing the ‘block’ in both limbs, the area was dissected bilaterally and the success was evaluated. A positive femoral nerve staining was considered for a coverage of ⩾1 cm. Results A total of 10 ultrasound-guided femoral nerve injections were performed. Ninety percent (n = 9/10) of the nerves were successfully dyed. Conclusions and relevance The novel ultrasound-guided lateral approach may be suitable and reproducible for a successful femoral nerve blockade in cats. Further investigations about the clinical usefulness and safety of this femoral nerve block in live cats are required.

To compare the nerve stimulation test (group NS) with the running-drip method (group RUN) for successful identification of the sacrococcygeal (SCo) epidural space prior to drug administration in dogs.A total of 62 dogs.A randomized clinical study.Dogs requiring an epidural anaesthetic as part of the multimodal anaesthetic plan were randomly allocated to one of the two study groups. In group NS, the epidural space was located using an insulated needle connected to a nerve stimulator; in group RUN, the epidural space was identified using a Tuohy needle connected to a fluid bag elevated 60 cm above the spine via an administration set. The success of the technique was assessed 5 minutes after epidural injection by the disappearance of the patella reflex. Data were checked for normality, nonparametric data was analysed using a Mann-Whitney U test and success rate was analysed using a Fisher's exact test. The significance level was set at p0.05, and the results are presented in absolute values, percentage (95% confident interval) and median (range).The success in identification of the epidural space did not differ between groups NS and RUN [87.1% (70.2%-96.4%) versus 90.3% (74.2%-98%); p = 1.000]. The time required for identification of the epidural space was shorter in group RUN [26 (15-53) seconds] than in group NS [40 (19-137) seconds] (p = 0.0225). No other differences were found in any studied variables.and clinical relevance In this study, both RUN and NS techniques were successful in identifying the epidural space at the SCo intervertebral space. RUN requires no specialised equipment, can be performed rapidly and offers an alternative to the NS for use in general veterinary practice.

Objective To compare two needle insertion techniques in a novel lateral approach to the radial, ulnar, median and musculocutaneous (RUMM) nerve block in cat cadavers. Study design Prospective, cadaveric experimental study. Animals A group of 18 feline cadavers. Methods Cadavers were divided into two groups. Both thoracic limbs of each cat were ‘blocked’ using the ‘in-plane’ (IP) or ‘out-of-plane’ (OP) ultrasound (US)-guided method. A single operator with limited experience performed all the techniques. Cadavers were placed in lateral recumbency and the uppermost limb was injected before turning to ‘block’ the contralateral limb in the same manner. The IP method consisted of tracking the triceps brachii muscle until the radial (R) nerve could be identified in the same field of view as the ulnar, median and musculocutaneous (UMM) nerve bundle. A needle was guided by US towards the R nerve and subsequently, methylene blue (0.4 mL) was instilled adjacent to it. The needle was retracted and redirected to the UMM nerve bundle, and another 0.4 mL dye was instilled. For the OP technique, the limb was pronated at a 45° angle. The nerves were then identified with the R nerve directly above UMM nerves. A needle was directed OP deep towards UMM nerves and dye (0.4 mL) was instilled. The needle was retracted superficially and 0.4 mL dye instilled next to the R nerve. After dissection, the nerves were assessed and ≥6 mm of staining was considered a successful technique. Results A total of 18 RUMM ‘blocks’ were performed IP and 18 were performed OP. The IP technique was more successful than the OP technique (R nerve p = 0.0339; UMM nerves p = 0.0352). Conclusions and clinical relevance The lateral approach to the RUMM was achievable in cat cadavers using both needle insertion techniques. The IP technique was significantly more successful than the OP technique.

Background The aim of the study was to discover the extent of use of essential fatty acids (EFAs) in veterinary practice, conditions used in, preparation of EFA supplement used and rationale for their use and to investigate the awareness of the oxidation of some commercial fish oil supplement preparations. Methods A web-based questionnaire was distributed via email to a dermatology list server and posted to veterinary Facebook groups with questions relating to the use of EFAs, supplement choice, conditions used in, the level of importance of various factors regarding their use and awareness of their oxidation. Results There were 309 responses from 32 countries. EFA supplements were used by 92.2 per cent of respondents. The most commonly used preparation of EFA supplementation was veterinary oral supplements (75.1 per cent), followed by veterinary diets (14.4 per cent), shop bought fish oil supplements (7.7 per cent), enhancing the diet with oily fish (2.5 per cent) and finally using a commercial pet food (0.3 per cent). Only 46.3 per cent of respondents who used them were aware of the oxidation of EFAs. Veterinary oral supplements were perceived to be the best preserved, followed by veterinary diets and lastly commercial fish oil supplements. Conclusion A large number of respondents advised the use of EFAs for veterinary dermatological conditions but less than 50 per cent were aware of the potential for EFAs to oxidise.

OBJECTIVE To quantify the effect of time and recumbency on CT measurements of lung volume and attenuation in healthy cats under general anesthesia. ANIMALS 8 healthy research cats. PROCEDURES Anesthetized cats were positioned in sternal recumbency for 20 minutes and then in left, right, and left lateral recumbency (40 minutes/position). Expiratory helical CT scan of the thorax was performed at 0 and 20 minutes in sternal recumbency and at 0, 5, 10, 20, 30, and 40 minutes in each lateral recumbent position. For each lung, CT measurements of lung volume and attenuation and the extent of lung areas that were hyperaerated (−1,000 to −901 Hounsfield units [HU]), normoaerated (−900 to −501 HU), poorly aerated (−500 to −101 HU), or nonaerated (−100 to +100 HU [indicative of atelectasis]) were determined with a semiautomatic threshold-based technique. A restricted maximum likelihood analysis was performed. RESULTS In lateral recumbency, the dependent lung had significantly greater attenuation and a lower volume than the nondependent lung. Within the dependent lung, there was a significantly higher percentage of poorly aerated lung tissue, compared with that in the nondependent lung. These changes were detected immediately after positioning the cats in lateral recumbency and remained static with no further significant time-related change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that once anesthetized healthy cats were positioned in lateral recumbency, the dependent lung lobes underwent a rapid reduction in lung volume and increase in lung attenuation that did not progress over time, predominantly attributable to an increase in poorly aerated lung tissue.

To determine whether the surgeon can influence the accuracy of milling during the TATE elbow arthroplasty by applying force to the milling arm during the milling procedure.In vitro study on Sawbone specimens.Thirty identical solid foam models of the canine right humerus, elbow joint, and antebrachium (size large).TATE elbow arthroplasty was performed on 30 elbows equally divided into 3 types of forces applied to the milling arm: (1) no force, (2) a maximally converging force, and (3) a maximally diverging force using the center of rotation post as a reference point. The resulting component-bone interface and post fit were quantified with digital photography.The component-bone interface gap differed between techniques for most angles. The application of convergent or divergent milling forces frequently increased the component-bone interface gap. Post fit was also influenced by the milling technique, application of a convergent or divergent milling force affecting the fit of multiple posts. Interface gaps tended to be greater on the lateral aspect, an area that is not visible to the surgeon intraoperatively.In this bone model study, application of convergent or divergent forces during milling frequently resulted in greater component-bone interface gaps and poorer post fit than when a neutral position was maintained.Surgeons may affect implant fit within the constraints of the current arthroplasty system if they do not maintain a neutral position during milling. Greater component-bone interface gaps and poorer post fit may affect component osseointegration and lead to aseptic implant loosening.

Opioid-free anaesthesia (OFA) is a relatively new and growing field in human medicine. There are multiple motivations behind this emerging practice with the recognition of several serious potential opioid-related adverse effects including opioid induced hyperalgesia, opioid tolerance and immunomodulatory effects of opioids. Opioids have long been the mainstay of veterinary anaesthesia and pain management practice. The feasibility of OFA in veterinary patients is presented here. A case series of three dogs that underwent OFA for canine ovariohysterectomy is reported. The authors conclude OFA is possible in veterinary medicine; however the move away from the familiar effects of opioids perioperatively is challenging. Gaining experience with these types of protocols for standard procedures in healthy animals, such as neutering, will provide the anaesthetist with the building blocks for more invasive surgeries.Keywords: Anaesthesia, Analgesia, Dog, Pain.

The study was designed to determine the effects of two protocols of sedation, medetomidine and medetomidine-butorphanol, on cerebral blood flow (CBF) by transcranial color-coded Duplex ultrasonography in healthy dogs. Transcranial Doppler ultrasonographic examination was performed in 20 dogs before and 20 min after sedation with either medetomidine (group 1) or medetomidine-butorphanol (group 2). The left and right middle cerebral arteries (LMCA and RMCA) were evaluated using the temporal windows, and the basilar artery (BA) was studied through the suboccipital window. Peak systolic velocity (PSV), mean velocity (MV), end diastolic velocity (EDV), resistance index (RI), and pulsatility index (PI) were measured for each vessel. Blood pressure (BP) and heart rate (HR) were also recorded before and after sedation in both groups. Statistically significant differences were found for PSV, MV and EDV when RMCA and LMCA were interrogated before and after sedation. PSV, RI and PI were found to be statistically significantly different when the study was performed on the BA. These results should be taken in account when a transcranial Doppler is performed in dogs sedated with the mentioned protocols and it might suggest some degree of neuroprotection.

This study aimed to evaluate the effect of lingual gauze swab placement on pulse oximeter readings in anaesthetised dogs and cats. Following anaesthetic induction, the following pulse oximeter probe configurations were performed: no gauze swab (control), placement of a gauze swab between the tongue and the probe, placement of different thicknesses of gauze swab, placement of red cotton fabric, placement of a sheet of white paper and placement of the probe and gauze swab on different locations on the tongue. Oxygen saturation (SpO2) and peripheral perfusion index (PI) were recorded. Placement of a gauze swab between the pulse oximeter probe and the tongue in anaesthetised dogs and cats resulted in significantly higher SpO2 values compared with the control group. In dogs, PI values were significantly higher than the control in all groups except the quarter thickness swab group. In cats, PI was significantly higher in the double thickness swab and white paper groups compared with the control. Cats had significantly higher SpO2 and lower PI values than dogs. The authors propose that increased contact pressure is responsible for significantly higher SpO2 and PI readings with the use of a lingual gauze swab resulting from changes in transmural pressure and arterial compliance.

Antibiotic prophylaxis in dogs undergoing surgical procedures frequently involves the administration of a product without a veterinary licence. Two drugs commonly used for this purpose are the clavulanate amoxicillin Augmentin and the cefuroxime Zinacef. This prospective observational study aims to compare the incidence of adverse events associated with these two antibiotics in a clinical setting. The authors hypothesised that a higher incidence of adverse effects would be observed with Augmentin. Sixty-five dogs were included in the study and adverse events were recorded using a modified scoring system. A significantly higher incidence of adverse events to Augmentin (8/22; 36 per cent) was observed compared with Zinacef (1/43; 2 per cent) (P=0.0003). The majority of these adverse events involved cutaneous signs and/or hypotension. These findings might be taken into consideration when selecting one of these intravenous antibiotics for prophylaxis in anaesthetised dogs undergoing surgery.

Objective To compare the running-drip and hanging-drop techniques for locating the epidural space in dogs. Study design Prospective, randomized, clinical trial. Animals Forty-five healthy dogs requiring epidural anaesthesia. Methods Dogs were randomized into four groups and administered epidural anaesthesia in sternal (S) or lateral (L) recumbency. All blocks were performed by the same person using Tuohy needles with either a fluid-prefilled hub (HDo) or connected to a drip set attached to a fluid bag elevated 60 cm (RDi). The number of attempts, ‘pop’ sensation, clear drop aspiration or fluid dripping, time to locate the epidural space (TTLES) and presence of cerebrospinal fluid (CSF) were recorded. A morphine–bupivacaine combination was injected after positive identification. The success of the block was assessed by experienced observers based on perioperative usage of rescue analgesia. Data were checked for normality. Binomial variables were analysed with the chi-squared or Fisher’s exact test as appropriate. Non-parametric data were analysed using Kruskal–Wallis and Mann–Whitney tests. Normal data were studied with an anova followed by a Tukey's means comparison for groups of the same size. A p-value of Results Lateral recumbency HDo required more attempts (six of 11 dogs required more than one attempt) than SRDi (none of 11 dogs) (p = 0.0062). Drop aspiration was observed more often in SHDo (nine of 11 dogs) than in LHDo (two of 11 dogs) (p = 0.045). Mean (range) TTLES was longer in LHDo [47 (18–82) seconds] than in SHDo [20 (14–79) seconds] (p = 0.006) and SRDi [(34 (17–53) seconds] (p = 0.038). There were no differences in ‘pop’ sensation, presence of CSF, rescue analgesia or pain scores between the groups. Conclusion and clinical relevance The running-drip method is a useful and fast alternative technique for identifying the epidural space in dogs. The hanging-drop technique in lateral recumbency was more difficult to perform than the other methods, requiring more time and attempts.

The aim of this study was to evaluate the analgesic effects of maxillary and/or inferior alveolar nerve blocks with lidocaine and bupivacaine in cats undergoing dental extractions. Twenty-nine cats were enrolled. Using an adapted composite pain scale, cats were pain scored before the dental procedure and 30 mins, and 1, 2 and 4 h after isoflurane disconnection. Cats were sedated with buprenorphine (20 µg/kg), medetomidine (10 µg/kg) and acepromazine (20 µg/kg) intramuscularly. Anaesthesia was induced using alfaxalone (1–2 mg/kg) intravenously and maintained with isoflurane in oxygen. Each cat was randomly assigned to receive maxillary and/or inferior alveolar nerve blocks or no nerve blocks prior to dental extractions. Each nerve block was performed using lidocaine (0.25 mg/kg) and bupivacaine (0.25 mg/kg). Heart rate, systolic arterial blood pressure, respiratory rate, end tidal carbon dioxide and isoflurane vaporiser settings were recorded 5 mins before and after the dental extractions, and the difference calculated. Group mean differences (mean ± SD) for heart rate (−9.7 ± 10.6 vs 7.6 ± 9.5 beats/min [nerve block vs control group, respectively], P

Objective To compare anaesthetic induction in healthy dogs using propofol or ketofol (a propofol-ketamine mixture). Study design Prospective, randomized, controlled, ‘blinded’ study. Animals Seventy healthy dogs (33 males and 37 females), aged 6–157 months and weighing 4–48 kg. Methods Following premedication, either propofol (10 mg mL−1) or ketofol (9 mg propofol and 9 mg ketamine mL−1) was titrated intravenously until laryngoscopy and tracheal intubation were possible. Pulse rate (PR), respiratory rate (fR) and arterial blood pressure (ABP) were compared to post-premedication values and time to first breath (TTFB) recorded. Sedation quality, tracheal intubation and anaesthetic induction were scored by an observer who was unaware of treatment group. Mann–Whitney or t-tests were performed and significance set at p ≤ 0.05. Results Induction mixture volume (mean ± SD) was lower for ketofol (0.2 ± 0.1 mL kg−1) than propofol (0.4 ± 0.1 mL kg−1) (p