Effect of dexmedetomidine constant rate infusion on the analgesic duration of peripheral nerve blocks in dogs: a randomized clinical study.

The aim of this study was to evaluate whether a constant rate infusion of dexmedetomidine could prolong the analgesic effect of peripheral nerve blocks. Twenty client-owned dogs were enrolled and randomly divided into 2 groups. The DEX group received dexmedetomidine infusion at 1 mcg kg-1 h-1, and the NaCl group received an equivalent volume infusion of saline. Infusions were started after securing vascular access and continued for 10 min, after which intravenous (IV) methadone at 0.2 mg kg-1 and propofol to effect were administered. All animals were maintained with isoflurane in 70% oxygen. Sciatic, saphenous and obturator nerve blocks were performed using 0.1 mL kg-1 0.5% ropivacaine/block. Intraoperative fentanyl was administered if the heart rate and/or mean arterial pressure (MAP) increased > 15% from the previous measurement, and vasopressors were administered if MAP was ≤ 70 mmHg. Postoperative pain was assessed every hour using the Glasgow Composite Pain Scale (GCPS) until the first rescue analgesia administration. Postoperative rescue analgesia (methadone (0.2 mg kg-1 IV) and carprofen (2 mg kg-1 IV)) was administered if the pain score was higher than 6/24 or 5/20. Duration of analgesia was defined as the time between the nerve block procedure and initial postoperative rescue analgesia. Ambulation, proprioception, and skin sensitivity were evaluated to assess the duration of the motor and sensory block. A Student T and chi-square test were used to compare groups for duration of postoperative analgesia and intraoperative fentanyl and vasopressor use, respectively (p values ≤ 0.5 considered significant). A greater number of dogs in the NaCl group required fentanyl (5/10 p = 0.03) and vasopressors (8/10, p = 0.02) than did those in the DEX group (0/10 and 2/10, respectively). The duration of postoperative analgesia was significantly longer (604 ± 130 min) in the DEX group than in the NaCl group (400 ± 81 min, p = 0.0005).Dexmedetomidine infusion at 1 mcg kg-1 h-1 delays the time to first administration of rescue analgesia and reduces intraoperative analgesic and vasopressor requirements during Tibial Tuberosity Advancement surgery.

Evaluation of the Quality of Recovery from General Anesthesia in Dogs with Two Different Low Doses of Dexmedetomidine.

The purpose of this study was to evaluate the quality of recovery from general anesthesia with the administration of two low doses of dexmedetomidine in canine patients. For this blind randomized clinical trial study, 30 dogs undergoing general anesthesia for diagnostic procedures or elective surgery (ovariectomy/castration) were included. The patients were randomly divided into three groups, and at the end of anesthesia, they received a bolus of dexmedetomidine at 1 mcg/kg IV (D1), or a bolus of dexmedetomidine at 0.5 mcg/kg (D0.5), or a bolus of NaCl, in a total of 0.5 mL of solution for all three groups. After administration of the bolus, the anesthetist monitored the patients every 5 min by measuring heart rate, systolic and mean blood pressure, respiratory rate, and oxygen saturation. The quality of recovery was also assessed using 4 different scales. The extubation time, time of headlift, and standing position were also recorded. Both groups receiving dexmedetomidine had better awakening and a lower incidence of delirium when compared to saline administration. The heart rate was lower, while the systolic pressure was higher in the two groups D1 and D0.5 compared to the NaCl with a low presence of atrioventricular blocks. The extubation time resulted significantly higher in the D1 (17 ± 6 min) compared to the D0.5 (10 ± 4 min) and NaCl (8 ± 3 min) (p < 0.0001); the headlift time D1 (25 ± 10 min) resulted significantly longer than the NaCl group (11 ± 5 min) (p = 0.0023) but not than the D0.5 (18 ± 9 min). No significant differences were found among the three groups for standing positioning (D1 50 ± 18 min, D0.5 39 ± 22 min, NaCl 28 ± 17 min). The preventive administration of a bolus of dexmedetomidine at a dosage of 0.5 mcg/kg or 1 mcg/kg IV during the recovery phase improves the quality of recovery in patients undergoing general anesthesia.

Impact of a Dexmedetomidine Intravenous Infusion in Septic Dogs: Preliminary Study.

The purpose of this study was to determine if a continuous rate infusion (CRI) of dexmedetomidine decreases vasopressor requirements in septic dogs undergoing surgery. Vital parameters, sequential organ failure assessment (SOFA) score, vasopressor requirement, and 28-day mortality were recorded. Dogs were randomly divided into two groups: a dexmedetomidine (DEX) (1 mcg/kg/h) group and a control group (NaCl), which received an equivalent CRI of NaCl. Dogs were premedicated with fentanyl 5 mcg/kg IV, induced with propofol, and maintained with sevoflurane and a variable rate fentanyl infusion. DEX or NaCl infusions were started 10 min prior to induction. Fluid-responsive hypotensive patients received repeated Ringer's lactate boluses (2 mL/kg) until stable or they were no longer fluid-responsive. Patients that remained hypotensive following fluid boluses received norepinephrine at a starting dose of 0.05 mcg/kg/min, with increases of 0.05 mcg/kg/min. Rescue adrenaline boluses were administered (0.001 mg/kg) if normotension was not achieved within 30 min of starting norepinephrine. The NaCl group received a significantly higher dose of norepinephrine (0.8, 0.4-2 mcg/kg/min) than the DEX group (0.12, 0-0.86 mcg/kg/min). Mortality was statistically lower in the DEX group (1/10) vs. the NaCl group (5/6). Results of this study suggest that a 1 mcg/kg/h CRI of dexmedetomidine decreases the demand for intraoperative vasopressors and may improve survival in septic dogs.

Respiratory Effects of Continuous Positive Airway Pressure Administered during Recovery from General Anesthesia in Brachycephalic Dogs.

This study aimed to evaluate the benefits of applying 5 cmH2O of CPAP using a pediatric helmet during the recovery phase from general anesthesia in brachycephalic dogs. Brachycephalic dogs undergoing various surgical procedures were included in this study, and a total of 64 subjects were randomly assigned to receive either standard oxygen supplementation (NO-CPAP group) or oxygen supplementation combined with CPAP (CPAP group). This study evaluated arterial blood pH, blood gas partial pressures of O2 and CO2, arterial blood O2 saturation, and related parameters during recovery. The dogs were monitored, and helmet tolerance was assessed using predefined criteria. Of the initially assessed 69 dogs, 64 were enrolled: 32 in the CPAP group and 32 in the NO-CPAP group. Fifteen dogs in the NO-CPAP group were excluded based on predetermined criteria. The CPAP group showed significant improvements in PaO2, PaO2/FiO2, P(A-a)O2, F-Shunt, and respiratory rate compared with the NO-CPAP group (p < 0.001). The incidence of reintubation and helmet intolerance was higher in the NO-CPAP group (18% and 15.6%, respectively) than in the CPAP group (0%). This study highlights the potential benefits of incorporating CPAP, delivered through a pediatric helmet, in the perioperative management of brachycephalic dogs.

Perioperative analgesic efficacy of lumbar erector spinae plane block in dogs undergoing hemilaminectomy: a randomized blinded clinical trial.

OBJECTIVE: To evaluate the perioperative analgesic effect of the unilateral lumbar erector spinae plane block (ESPBL) in dogs undergoing hemilaminectomy. STUDY DESIGN: Randomized, blinded clinical study. ANIMALS: A total of 30 client-owned dogs undergoing thoracolumbar or lumbar hemilaminectomy for intervertebral disc extrusion (IVDE). METHODS: Dogs were randomly assigned to receive a unilateral ESPBL, performed either with 0.4 mL kg-1 ropivacaine 0.5% [group ROPI (n = 15)] or with saline solution [CNT group (n = 15)]. Dogs were premedicated intravenously (IV) with acepromazine 5 µg kg-1 and methadone 0.2 mg kg-1, general anaesthesia was induced by administering IV midazolam 0.2 mg kg-1 and propofol to effect and maintained with isoflurane. Fentanyl was administered as rescue analgesia. Bradycardia [heart rate (HR) < 60 beats minute-1] with hypotension was treated with atropine IV. The Short-Form of the Glasgow Composite Pain Scale was used pre- and postoperatively at 1, 2, 4, 8, 12, 16, 20 and 24 hours after extubation, and methadone 0.2 mg kg-1 was administered IV when pain score was ≥ 5/20. HR and end-tidal concentration of isoflurane (Fe'Iso) were compared between groups with anova combined with a Dunnet's post hoc test. Time to the first rescue methadone and total dose of fentanyl (FENtot, µg kg-1 hour-1) and methadone (METtot, mg kg-1) in the first 24 postoperative hours were compared using unpaired Student's t test. Postoperative pain scores were compared with the Mann-Whitney test and atropine administration with a Fisher's exact test; p < 0.05. RESULTS: HR, Fe'Iso, FENtot, METtot and atropine administration were significantly lower in group ROPI compared to CNT. Postoperative analgesic effect was significantly longer, and pain scores were significantly lower in group ROPI for all time points. CONCLUSIONS AND CLINICAL RELEVANCE: Unilateral ESPBL with ropivacaine reduced perioperative opioid consumption and the occurrence of bradycardia in dogs undergoing hemilaminectomy.

Six-Year Prescription Pattern of Antimicrobial Use in Cats at the Veterinary Teaching Hospital of the University of Pisa.

The use of antimicrobials has greatly contributed to improving animal health. However, their inappropriate use reduces their effectiveness in treating bacterial infections and contributes to the selection of resistance. This study aimed to retrospectively evaluate the six-year pattern (2017-2022) of antimicrobial use in cats visiting the Veterinary Teaching Hospital (VTH) of the University of Pisa (Italy). The total number of prescribed antimicrobials, the number of animals for which an antimicrobial was prescribed, and the total number of antimicrobial prescriptions showed a significant time trend decrease during the study period, except for the fixed-dose combinations. The most frequently prescribed antimicrobials were amoxicillin-clavulanic acid (Synulox) (39.1%) followed by enrofloxacin (29.8%). These antimicrobials were mostly prescribed to treat infections affecting the genitourinary tract (~30%), followed by the gastrointestinal tract, skin, and respiratory system affections. Antimicrobials in empirical associations represented 13.0% of the total antimicrobial prescriptions, and the combination of amoxicillin-clavulanic acid (Synulox) with enrofloxacin accounted for the majority. The oral route represented the main route of administration of prescribed antimicrobials, followed by parenteral and topical ones. Amoxicillin-clavulanic acid (Synulox) (37.2%), ceftriaxone (2.7%), and tobramycin (2.8%) were the most prescribed antimicrobials for the oral, parenteral, and topical routes, respectively. Antimicrobial prescriptions complied with prudent use recommendations in terms of availability of diagnosis, respect to the dose range, duration of treatment, and the use of medicinal products approved for the species. On the contrary, antimicrobial susceptibility tests were used infrequently (5.2%), lacking compliance with the existing guidelines observed in companion animal practice. Overall, additional interventions are required not only to improve the responsible use of antimicrobials in our feline practice but also to implement antimicrobial stewardship programs, enhancing diagnostics such as culture and sensitivity testing in the future.

Swine Pudendal Nerve as a Model for Neuromodulation Studies to Restore Lower Urinary Tract Dysfunction.

Lower urinary tract dysfunction, such as incontinence or urinary retention, is one of the leading consequences of neurological diseases. This significantly impacts the quality of life for those affected, with implications extending not only to humans but also to clinical veterinary care. Having motor and sensory fibers, the pudendal nerve is an optimal candidate for neuromodulation therapies using bidirectional intraneural prostheses, paving the way towards the restoration of a more physiological urination cycle: bladder state can be detected from recorded neural signals, then an electrical current can be injected to the nerve based on the real-time need of the bladder. To develop such prostheses and investigate this novel approach, animal studies are still required since the morphology of the target nerve is fundamental to optimizing the prosthesis design. This study aims to describe the porcine pudendal nerve as a model for neuromodulation studies aiming at restoring lower urinary tract dysfunction. Five male farm pigs were involved in the study. First, a surgical procedure to access the porcine pudendal nerve without muscle resection was developed. Then, an intraneural interface was implanted to confirm the presence of fibers innervating the external urethral sphincter by measuring its electromyographic activity. Finally, the morphophysiology of the porcine pudendal nerve at the level of surgical exposure was described by using histological and immunohistochemical characterization. This analysis confirmed the fasciculate nature of the nerve and the presence of mixed fibers with a spatial and functional organization. These achievements pave the way for further pudendal neuromodulation studies by using a clinically relevant animal model with the potential for translating the findings into clinical applications.

Saphenous and Sciatic Nerve Blockade with and without Obturator Nerve Block for Tibial Plateau Levelling Osteotomy Surgery in Dogs: A Randomized Controlled Trial.

The objective of our study was to compare the efficacy of sciatic and saphenous ultrasound nerve blocks with and without US-guided obturator nerve block in dogs undergoing tibial-plateau-levelling-osteotomy (TPLO) surgery. This study was developed in two phases: identification of an ultrasound window in the inguinal region for obturator nerve block and utilization of it in dogs undergoing TPLO. Dogs were assigned randomly to one of two groups: one received the three blocks with 0.5% ropivacaine (ON group) and the second one (NoON group) with NaCl instead of ropivacaine for the obturator block. In phase 1, the obturator nerve was visible between the pectineus and the abductor muscles and was approached using an in-plane technique. It was possible to use the ultrasound window for phase two. The number of dogs that received at least one bolus of intraoperative rescue analgesia in the NoON group (12/15 dogs) was significantly higher (p = 0.003) in comparison with the ON group (4/15). An ultrasound window to block the obturator nerve in the inguinal compartment with an in-plane technique was found. The use of this approach could produce adequate analgesia with less motor function impairment in dogs for TPLO surgery.