Brain perfusion magnetic resonance imaging using pseudocontinuous arterial spin labeling in 314 dogs and cats.

BACKGROUND: Arterial spin labeling (ASL) is a noninvasive brain perfusion magnetic resonance imaging (MRI) technique that has not been assessed in clinical veterinary medicine. HYPOTHESIS/OBJECTIVES: To test the feasibility of ASL using a 1.5 Tesla scanner and provide recommendations for optimal quantification of cerebral blood flow (CBF) in dogs and cats. ANIMALS: Three hundred fourteen prospectively selected client-owned dogs and cats. METHODS: Each animal underwent brain MRI including morphological sequences and ≥1 ASL sequences using different sites of blood labeling and postlabeling delays (PLD). Calculated ASL success rates were compared. The CBF was quantified in animals that had morphologically normal brain MRI results and parameters of ASL optimization were investigated. RESULTS: Arterial spin labeling was easily implemented with an overall success rate of 95% in animals with normal brain MRI. Technical recommendations included (a) positioning of the imaging slab at the foramen magnum and (b) selected PLD of 1025 ms in cats and dogs <7 kg, 1525 ms in dogs 7 to 38 kg, and 2025 ms in dogs >38 kg. In 37 dogs, median optimal CBF in the cortex and thalamic nuclei were 114 and 95 mL/100 g/min, respectively. In 28 cats, median CBF in the cortex and thalamic nuclei were 113 and 114 mL/100 g/min, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Our survey of brain perfusion ASL-MRI demonstrated the feasibility of ASL at 1.5 Tesla, suggested technical recommendations and provided CBF values that should be helpful in the characterization of various brain diseases in dogs and cats.

Analysis of teaching methods in anaesthesia in the undergraduate curriculum of four veterinary universities.

OBJECTIVE: To design a holistic audit tool to assess the effectiveness of anaesthesia teaching strategies, and thereby to study veterinary undergraduate teaching methods in different geographical areas. STUDY DESIGN: Qualitative study using interviews of university staff and students to identify common themes and differences in teaching veterinary anaesthesia. METHODS: An audit was performed using an audit tool in four veterinary universities (École Nationale Vétérinaire d'Alfort, France; Royal Veterinary College, UK; University of Buenos Aires, Argentina; and Alma mater studiorum - Università di Bologna, Italy). First, an open-question interview of anaesthesia head of service (60-90 minutes) identified the pedagogical strategies in order to conceive a subsequent semi-directive interview formulated as a SWOT analysis (Strength/Weaknesses/Opportunity/Threats). Second, the SWOT reflection was conducted by a second staff member and focussed on: 1) general organization; 2) topics for pre-rotation teaching; 3) teaching methods for clinical rotation; and 4) assessment methods. Qualitative analysis of the interview responses was performed with semi-structured interviews. Finally, the students evaluated their teaching through a students' questionnaire generated from the output of both interviews. RESULTS: A group of nine lecturers and 106 students participated in the study at four different sites. Preclinical teaching ranged from 13 to 24 hours (median 15 hours). Clinical teaching ranged from 4 to 80 hours (median 60 hours). Overall, all faculties perceived time as a limitation and attempted to design strategies to achieve the curriculum expectations and optimize teaching using more time-efficient exercises. Large animal anaesthesia teaching was found to be a common area of weakness. Internal feedback was delivered to each university, whereas generalized results were shared globally. CONCLUSIONS: This preliminary study proved the generalizability of the protocol used. Recruiting a larger pool of universities would help to identify and promote efficient teaching strategies and innovations for training competent new graduates in an ever-expanding curriculum.

Neonatal puppy survival after planned caesarean section in the bitch using aglepristone as a primer: A retrospective study on 74 cases.

Since most of dystocia end up in caesarean sections (C-sections), the history of any problem during whelping is a good reason to plan in advance a further C-section. Our aim was to confirm that on a large sample and over an extended period of time, mortality in puppies <2 weeks of age was low, born after a planned C-section using aglepristone as a primer. Seventy-four C-sections on 59 different bitches were included. Bitches were monitored during oestrus to estimate the day of ovulation by progesterone assays; 60, 61 or 62 days after ovulation, foetal viability was checked by ultrasonography and progesterone plasma level was measured. None of the bitches was at term (progesterone plasma level >2 ng/ml). An injection of aglepristone was performed in late afternoon to block the effect of progesterone, mimicking its drop at the end of pregnancy. The C-section was conducted the following morning. Twenty-one breeds were represented most of which were bulldogs (26%, 21/74) and Great Danes (16%, 13/74). Four hundred and thirty-five puppies were born. A total of 43/435 puppies died within the first 2 weeks (9.89%). None of the puppies showed any external signs of prematurity. The average number of deaths per litter relative to the date after ovulation was similar (0.5 pups per litter at day 60, 0.7 at day 61, 0.4 at day 62). This study shows that planned C-section after an accurate determination of ovulation and using aglepristone as a primer is a safe procedure for bitches and their offspring. It may be offered to owners if a pregnant bitch is "at risk" of dystocia.

Hypothermic total liquid ventilation after experimental aspiration-associated acute respiratory distress syndrome.

BACKGROUND: Ultrafast cooling by total liquid ventilation (TLV) provides potent cardio- and neuroprotection after experimental cardiac arrest. However, this was evaluated in animals with no initial lung injury, whereas out-of-hospital cardiac arrest is frequently associated with early-onset pneumonia, which may lead to acute respiratory distress syndrome (ARDS). Here, our objective was to determine whether hypothermic TLV could be safe or even beneficial in an aspiration-associated ARDS animal model. METHODS: ARDS was induced in anesthetized rabbits through a two-hits model including the intra-tracheal administration of a pH = 1 solution mimicking gastric content and subsequent gaseous non-protective ventilation during 90 min (tidal volume [Vt] = 10 ml/kg with positive end-expiration pressure [PEEP] = 0 cmH2O). After this initial period, animals either received lung protective gas ventilation (LPV; Vt = 8 ml/kg and PEEP = 5 cmH2O) under normothermic conditions, or hypothermic TLV (TLV; Vt = 8 ml/kg and end-expiratory volume = 15 ml/kg). Both strategies were applied for 120 min with a continuous monitoring of respiratory and cardiovascular parameters. Animals were then euthanized for pulmonary histological analyses. RESULTS: Eight rabbits were included in each group. Before randomization, all animals elicited ARDS with arterial oxygen partial pressure over inhaled oxygen fraction ratios (PaO2/FiO2) below 100 mmHg, as well as decreased lung compliance. After randomization, body temperature rapidly decreased in TLV versus LPV group (32.6 ± 0.6 vs. 38.2 ± 0.4 °C after 15 min). Static lung compliance and gas exchanges were not significantly different in the TLV versus LPV group (PaO2/FiO2 = 62 ± 4 vs. 52 ± 8 mmHg at the end of the procedure, respectively). Mean arterial pressure and arterial bicarbonates levels were significantly higher in TLV versus LPV. Histological analysis also showed significantly lower inflammation in TLV versus LPV group (median histological score = 3 vs. 4.5/5, respectively; p = 0.03). CONCLUSION: Hypothermic TLV can be safely induced in rabbits during aspiration-associated ARDS. It modified neither gas exchanges nor respiratory mechanics but reduced lung inflammation and hemodynamic failure in comparison with LPV. Since hypothermic TLV was previously shown to provide neuro- and cardio protective effects after cardiac arrest, these findings suggest a possible use of TLV in the settings of cardiac arrest-associated ARDS.

Dexmedetomidine-methadone-ketamine versus dexmedetomidine-methadone-alfaxalone for cats undergoing ovariectomy.

OBJECTIVE: To compare the duration, quality of anaesthesia and analgesia, and quality of recovery of dexmedetomidine and methadone combined with either ketamine or alfaxalone. STUDY DESIGN: Randomized, prospective clinical trial. ANIMALS: A group of 44 healthy client-owned cats presenting for ovariectomy. METHODS: Cats were randomly assigned to one of the two treatment groups: DAM (n=22), which was administered intramuscularly (IM) dexmedetomidine (15 µg kg-1), methadone (0.3 mg kg-1) and alfaxalone (3 mg kg-1), and DKM (n=22), which was administered IM dexmedetomidine (15 µg kg-1), methadone (0.3 mg kg-1) and ketamine (3 mg kg-1). During anaesthesia, heart rate, respiratory rate and systolic arterial pressure were measured every 5 minutes. Cats that moved or had poor muscle relaxation were administered an additional 1 mg kg-1 of either alfaxalone (DAM) or ketamine (DKM) intravenously (IV). In cases of increased autonomic responses to surgical stimulation, fentanyl (2 µg kg-1) was administered IV. At the end of the surgery, atipamezole (75 µg kg-1) was administered IM, and the times to both sternal recumbency and active interaction were recorded. Quality of recovery was evaluated with a simple descriptive scale. The UNESP-Botucatu multidimensional composite pain scale and a visual analogue scale were used to evaluate postoperative analgesia at the return of active interaction and 1, 2 and 3 hours later. RESULTS: The additional anaesthesia and rescue fentanyl requirements were similar between groups. The quality of recovery was better in the DAM group than in the DKM group [simple descriptive scale scores: 0 (0-1) and 1 (0-3), respectively; p=0.002]. Postoperative pain scores decreased progressively over time in both groups, with no significant differences (p=0.08) between them. CONCLUSIONS AND CLINICAL RELEVANCE: Both protocols provided comparable quality of anaesthesia and analgesia and were suitable for cats undergoing ovariectomy. In combination with methadone and dexmedetomidine, alfaxalone and ketamine showed comfortable and reliable recoveries.

The Carmat Bioprosthetic Total Artificial Heart Is Associated With Early Hemostatic Recovery and no Acquired von Willebrand Syndrome in Calves.

OBJECTIVES: To determine hemostasis perturbations, including von Willebrand factor (VWF) multimers, after implantation of a new bioprosthetic and pulsatile total artificial heart (TAH). DESIGN: Preclinical study SETTING: Single-center biosurgical research laboratory. PARTICIPANTS: Female Charolais calves, 2-to-6 months old, weighing 102-to-122 kg. INTERVENTIONS: Surgical implantation of TAH through a mid-sternotomy approach. MEASUREMENTS AND MAIN RESULTS: Four of 12 calves had a support duration of several days (4, 4, 8, and 10 days), allowing for the exploration of early steps of hemostasis parameters, including prothrombin time; coagulation factor levels (II, V, VII+X, and fibrinogen); and platelet count. Multimeric analysis of VWF was performed to detect a potential loss of high-molecular weight (HMW) multimers, as previously described for continuous flow rotary blood pumps. Despite the absence of anticoagulant treatment administered in the postoperative phase, no signs of coagulation activation were detected. Indeed, after an immediate postsurgery decrease of prothrombin time, platelet count, and coagulation factor levels, most parameters returned to baseline values. HMW multimers of VWF remained stable either after initiation or during days of support. CONCLUSIONS: Coagulation parameters and platelet count recovery in the postoperative phase of the Carmat TAH (Camat SA, Velizy Villacoublay Cedex, France) implantation in calves, in the absence of anticoagulant treatment and associated with the absence of decrease in HMW multimers of VWF, is in line with early hemocompatibility that is currently being validated in human clinical studies.

Comparison of intratesticular lidocaine, sacrococcygeal epidural lidocaine and intravenous methadone in cats undergoing castration: a prospective, randomized, investigator-blind clinical trial.

OBJECTIVE: The objective of this study was to compare three analgesic protocols for feline castration. STUDY DESIGN: Prospective, randomized clinical study. ANIMALS: Forty-nine client-owned cats. METHODS: Cats were injected with intramuscular (IM) dexmedetomidine (15 µg kg-1) and alfaxalone (3 mg kg-1) and assigned randomly to one of three treatment groups. Group ITL (n = 15) were administered intratesticular 2% lidocaine (0.05 mL each testicle), group SCL (n = 15) a sacrococcygeal epidural injection of 2% lidocaine (0.1 mL kg-1) and group IVM (n = 19) intravenous (IV) methadone (0.3 mg kg-1), before surgery. Cardiorespiratory variables were recorded. In case of autonomic nociceptive response, IV fentanyl (2 µg kg-1) was administered. During recovery, time from IM atipamezole (75 µg kg-1, administered at the end of surgery) to sternal recumbency and to active interaction was recorded. Quality of recovery was assessed using a simple descriptive scale. Postoperative analgesia was evaluated using a visual analogue scale and the UNESP-Botucatu multidimensional composite pain scale (MCPS) at return of active interaction and then 1, 2 and 3 hours later. RESULTS: The three analgesic protocols were comparable in terms of intraoperative fentanyl and propofol requirement. Cardiorespiratory variables stayed within normal ranges in the majority of the cases, although group IVM had the lowest intraoperative respiratory rate (p = 0.0009). No differences were detected between groups in UNESP-Botucatu MCPS scores (p = 0.21). However, group ITL showed higher visual analogue scale score than group IVM (p = 0.001). Four cats enrolled in group ITL, as well as three of group SCL and one of group IVM, required rescue analgesics before the completion of pain assessment. CONCLUSIONS AND CLINICAL RELEVANCE: Intratesticular and sacrococcygeal epidural lidocaine injections could be regarded as good alternatives to systemic opioids in cats undergoing castration, although the benefits of these techniques seem to be of shorter duration than IV methadone.

Animal studies with the Carmat bioprosthetic total artificial heart.

OBJECTIVES: The Carmat bioprosthetic total artificial heart (TAH) contains bioprosthetic blood-contacting surfaces, and is designed for orthotopic cardiac replacement. In preparation for clinical studies, we evaluated the TAH performance and its effects on end-organ function in an animal model. METHODS: Twelve female Charolais calves, 2-3 months of age and weighing 102-122 kg, were implanted with the TAH through a mid-sternotomy to ensure an adequate anatomic fit. The intended support duration was 4-10 days. Haematological values, creatinine, bilirubin and lactate levels were measured and mean arterial and central venous pressure, central venous oxygen saturation and TAH parameters were monitored. RESULTS: The calves were placed in a cage immediately postoperatively, and extubated on postoperative day 1 in most cases. Average support duration was 3 days, with 4 of 12 calves supported for 4, 4, 8 and 10 days. The initial procedures were used to refine surgical techniques and postoperative care. Pump output ranged from 7.3 to 10 l/min. Haemodynamic parameters and blood analysis were within acceptable ranges. No device failures occurred. No anticoagulation was used in the postoperative phase. The calves were euthanized in case of discomfort compromising the animal well-being, such as respiratory dysfunction, severe blood loss and cerebral dysfunction. Device explant analysis showed no thrombus formation inside the blood cavities. Histological examination of kidneys showed isolated micro-infarction in 2/12 animals; brain histology revealed no thromboembolic depositions. CONCLUSION: The Carmat bioprosthetic TAH implanted in calves up to 10 days provided adequate blood flow to organs and tissues. Low levels of haemolysis and no visible evidence of thromboembolic depositions in major organs and device cavities, without the use of anticoagulation, may indicate early-phase haemocompatibility of the TAH.

Intramuscular administration of alfaxalone for sedation in rabbits.

Alfaxalone is a neuroactive steroid derivative of pregnanedione that was recently reintroduced to the market for use as an induction agent in small animal anaesthesia. The aim of this study was to determine an intramuscular alfaxalone dose for safe immobilisation. Ten healthy New Zealand white rabbits were used to evaluate a single intramuscular injection of alfaxalone. The design of the study was a three-way, complete block, cross-over trial to compare the effect of alfaxalone at three doses (4, 6 and 8 mg). The mean duration of the effect for the 4, 6 and 8 mg/kg doses was, respectively, 36.9 (95% CI (31.6 to 42.3)), 51.8 (46.4 to 57.2) and 58.4 (52.8 to 63.9) minutes. The loss of the righting reflex was achieved after 3.1 (2.5 to 3.8), 2.4 (1.7 to 3.1) and 2.3 (1.6 to 2.9) minutes, respectively. The mean duration of the effect for the 6 and 8 mg doses was significantly higher than for the 4 mg dose (with estimated differences of 14.8 95% CI (8.8 to 20.8) minutes and 21.4 (15.3 to 27.6) minutes, respectively). No significant dose effect was observed before the loss of the righting reflex (P=0.14). Ear pinching and limb withdrawal were elicited in all groups at every dose. Doses of 4 or 6 mg/kg could be recommended; higher doses do not provide clinical benefits and can be associated with anaesthetic complication.

Antinociceptive activity of pre- versus post-operative intra-articular bupivacaine in goats undergoing stifle arthrotomy.

OBJECTIVE: To evaluate the peri-operative analgesic efficacy of intra-articular bupivacaine administered before or after stifle arthrotomy. STUDY DESIGN: Prospective, randomized, blind, placebo-controlled experimental trial. ANIMALS: Thirty-nine healthy goats. METHODS: The goats were allocated randomly to one of three intra-articular treatment groups: group PRE (bupivacaine before and saline after surgery), group POST (saline before and bupivacaine after surgery) and group CON (saline before and after surgery). Anaesthesia was maintained with a constant end-tidal sevoflurane of 2.5%. Intra-operatively heart rate (HR), respiratory rate and mean arterial blood pressure (MAP) after critical surgical events (CSE) were recorded and compared with pre-incision values. Propofol requirements to maintain surgical anaesthesia were recorded. Flunixin was administered for 5 days. Post-operative pain assessment at 20 minutes, 2 hours, 4 hours after recovery and on day 2 and 3 included a multidimensional pain score (MPS), a lameness score and mechanical nociceptive threshold (MNT) testing. Rescue analgesia consisted of systemic opioids. Data were analysed using Kruskal-Wallis, Mann-Whitney, Friedman or chi-square tests as appropriate. RESULTS: Intra-operatively, group PRE had lower HR and MAP at several CSEs than groups POST/CON and required less propofol [0 mg kg(-1) (0-0 mg kg(-1))] than group POST/CON [0.3 mg kg(-1) (0-0.6 mg kg(-1))]. Post-operatively, group POST had significantly higher peri-articular MNTs than groups PRE and CON up to 4 hours after recovery. No treatment effect was detected for MPS, lameness scores and rescue analgesic consumption at any time point. CONCLUSIONS AND CLINICAL RELEVANCE: Pre-operative intra-articular bupivacaine provided notable intra-operative analgesia in goats undergoing stifle arthrotomy but did not reduce post-operative pain. Post-operative intra-articular bupivacaine provided a short lasting reduction of peri-articular hyperalgesia without affecting the requirements for systemic analgesia. Multimodal perioperative pain therapy is recommended to provide adequate analgesia for stifle arthrotomy in goats.

The effect of local anaesthesia on anaesthetic requirements for feline ovariectomy.

A dose of supplementary ketamine was used to evaluate the anaesthetic sparing effect of adding local anaesthesia to general anaesthesia in cats undergoing ovariectomy. Fifty-six healthy cats were randomly assigned to receive lidocaine 2% (group L) as skin infiltration (1 mg kg(-1)), topical application (splash block) on both the ovaries (2 mg kg(-1), each) and on abdominal muscular layers (1 mg kg(-1)), or an equal volume of NaCl 0.9% at the same sites (group S). Anaesthesia was induced with a mixture of 20 microg kg(-1) medetomidine and 5 mg kg(-1) ketamine administered intramuscularly. Rectal temperature, ECG, heart rate and respiratory rate were measured continuously. Ketamine supplemental boli (1 mg kg(-1), intravenously) were administered in response to movements during surgery. Local lidocaine significantly reduced the need for supplementary ketamine. All animals were returned to their owners without complications. With this protocol, local anaesthetics reduced the need for injectable anaesthetic during feline ovariectomy.

Assessment of repeatability, reproducibility, and effect of anesthesia on determination of radial and longitudinal left ventricular velocities via tissue Doppler imaging in dogs.

OBJECTIVE: To determine left ventricular free wall (LVFW) motions and assess their intra- and interday variability via tissue Doppler imaging (TDI) in healthy awake and anesthetized dogs. ANIMALS: 6 healthy adult Beagles. PROCEDURE: n the first part of the study, 72 TDI examinations (36 radial and 36 longitudinal) were performed by the same observer on 4 days during a 2-week period in all dogs. In the second part, 3 dogs were anesthetized with isoflurane and vecuronium. Two measurements of each TDI parameter were made on 2 consecutive cardiac cycles when ventilation was transiently stopped. The TDI parameters included maximal systolic, early, and late diastolic LVFW velocities. RESULTS: The LVFW velocities were significantly higher in the endocardial than in the epicardial layers and also significantly higher in the basal than in the mid-segments in systole, late diastole, and early diastole. The intraday coefficients of variation (CVs) for systole were 16.4% and 22%, and the interday CV values were 11.2% and 16.4% in the endocardial and epicardial layers, respectively. Isoflurane anesthesia significantly improved the intraday CV but induced a decrease in LVFW velocities, except late diastolic in endocardial layers and early diastolic in epicardial layers. CONCLUSIONS AND CLINICAL RELEVANCE: Left ventricular motion can be adequately quantified in dogs and can provide new noninvasive indices of myocardial function. General anesthesia improved repeatability of the procedure but cannot be recommended because it induces a decrease in myocardial velocities.

Familial aortic aneurysm in Leonberg dogs.

A thoracic aortic aneurysm was diagnosed in a 6-month-old male Leonberg dog by use of radiography, transthoracic and transesophageal echocardiography, and magnetic resonance imaging. The aneurysm was associated with a twisted ascending aorta and dilatation of several other thoracic arteries (pulmonary trunk, brachiocephalic trunk, and left subclavian artery). Histologic examination of the aorta revealed cystic medial necrosis, with disruption of the elastic network, collagen fibers, and the muscle glycoprotein fibrillin-1. The dam and sire of the dog and 8 littermates were examined by use of transthoracic echocardiography. The sire and 1 male littermate also had an aneurysm of the ascending aorta. To the authors' knowledge, this is the first report of familial aortic aneurysm in dogs.