Evaluation and comparison of postoperative analgesic effects of dexketoprofen and methadone in dogs.

OBJECTIVE: To evaluate and compare the analgesic efficacy and adverse effects of dexketoprofen and methadone using a noninferiority trial, during the first 24 postoperative hours in dogs undergoing orthopaedic surgery. STUDY DESIGN: Randomized, blinded clinical study. ANIMALS: A total of 38 healthy dogs undergoing orthopaedic surgery. METHODS: Dogs were premedicated with dexmedetomidine [1 µg kg-1 intravenously (IV)] followed by dexketoprofen (1 mg kg-1 IV; group DK) or methadone (0.2 mg kg-1 IV; group M). Anaesthesia was induced with propofol and maintained with isoflurane in 60% oxygen. Postoperatively, dexketoprofen was administered every 8 hours (group DK) and methadone every 4 hours (group M). Analgesia was assessed at baseline and at 1, 2, 4, 6, 18 and 24 hours after extubation using a dynamic and interactive visual analogue scale (DIVAS), the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF), mechanical wound thresholds (MWTs) and plasma cortisol levels. If CMPS-SF score was ≥5, rescue analgesia was administered. Data were analysed using a general linear mixed model, Mann-Whitney U test and chi-squared test as appropriate; a p value <0.05 was considered significant. RESULTS: The CMPS-SF and DIVAS scores were significantly higher in group M compared with group DK and remained higher for a longer period in group M, although the differences were not clinically significant. No significant differences were found in MWT assessment between groups. Plasma cortisol level significantly increased 2 hours after extubation, without significant differences between treatments. Rescue analgesia was administered to three animals (one in group DK; two in group M). CONCLUSION AND CLINICAL RELEVANCE: We conclude that 1 mg kg-1 IV dexketoprofen administered every 8 hours during the first 24 hours postoperatively is noninferior to methadone in controlling pain after orthopaedic surgery in dog, although frequent pain assessments are recommended to adjust the analgesia plan.

Comparison between Ultrasonographic-Guided Temporal and Coronoid Approaches for Trigeminal Nerve Block in Dogs: A Cadaveric Study.

The trigeminal nerve is responsible for innervating the periorbita. Ultrasound-guided trigeminal block is employed in humans for trigeminal neuralgia or periorbital surgery. There are no studies evaluating this block in dogs. This study aims to evaluate and compare two approaches (coronoid and temporal) of the trigeminal nerve block. We hypothesised superior staining with the coronoid approach. Thirteen dog heads were used. After a preliminary anatomical study, two ultrasound-guided injections per head (right and left, coronoid and temporal approach, randomly assigned), with an injectate volume of 0.15 mL cm-1 of cranial length, were performed (iodinated contrast and tissue dye mixture). The ultrasound probe was placed over the temporal region, visualising the pterygopalatine fossa. For the temporal approach, the needle was advanced from the medial aspect of the temporal region in a dorsoventral direction. For the coronoid approach, it was advanced ventral to the zygomatic arch in a lateromedial direction. CT scans and dissections were conducted to assess and compare the position of the needle, the spread of the injectate, and nerve staining. No significant differences were found. Both approaches demonstrated the effective interfascial distribution of the injectate, with some minimal intracranial spread. Although the coronoid approach did not yield superior staining as hypothesised, it presents a viable alternative to the temporal approach. Studies in live animals are warranted to evaluate clinical efficacy and safety.

Assessment of an Ultrasound-Guided Rectus Sheath Block in Foals: A Cadaveric Study.

In neonatal equines, pathologies involving umbilical structures are an important cause of morbidity, and surgical removal of urachal remnants is a common procedure in clinical practice. Surgery involving the ventral abdominal wall can cause substantial pain, leading to complications and prolonged recovery. The objectives of this study were to describe a two-point bilateral ultrasound-guided rectus sheath block at the level of the umbilicus and to evaluate the extent of dye distribution in foal cadavers. Ten foal cadavers were included in the study, in which a bilateral two-point ultrasound-guided rectus sheath block was performed-one injection 5 cm cranially and a second one 5 cm caudally to the umbilicus. The injectate consisted of a mixture of iodinated contrast medium and blue dye at a volume of 0.25 mL kg-1 per injection point (total 1 mL kg-1). After the injection, computer tomography and subsequent dissection of the ventral abdominal wall were performed. The extension of the contrast medium, the number of stained nerves, and contamination of the abdominal cavity were evaluated. The cranio-caudal extension of the contrast ranged from 0.8 to 1.4 cm per milliliter of injectate. The most commonly stained ventral branches of spinal nerves were thoracic (Th) nerves 16, 17, and 18 (95%, 85%, and 80% of the nerves, respectively). Abdominal contamination was found in four animals. The results suggest that the block could provide periumbilical analgesia. Further studies with different volumes of injectate and living animals are warranted.

Treatment of a Paroxysmal Atrioventricular Block by Implantation of a Bipolar, Single-Chamber Cardiac Pacemaker in a Donkey.

CASE SUMMARY: A two-year-old donkey presented with recurrent syncope. Electrocardiography revealed periods without any atrioventricular conduction and without any ventricular escape rhythm with a duration of up to one minute. Finally, atrioventricular conduction resumed spontaneously with a preceding ventricular escape beat. Laboratory tests and echocardiography identified no reversible cause. The diagnosis of a paroxysmal atrioventricular block (PAVB) was made. Therefore, a single-chamber cardiac pacemaker was implanted under general anesthesia. The device was programmed in the VVI mode to prevent further syncope. The therapy was considered successful as the donkey revealed no further syncope during the follow-up period of 17 months. CLINICAL RELEVANCE: Clinically relevant bradycardia is rare in equids. This is the first report to our knowledge to describe a PAVB, a term commonly used in human medicine, in a donkey. Detailed information about the diagnosis and the successful therapy is included, with a special focus on the implantation and programming of the permanent pacemaker.

Description of a novel ultrasound guided peribulbar block in horses: a cadaveric study.

BACKGROUND: Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). OBJECTIVE: To describe a technique for USG PB in horse cadavers. METHODS: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised to two operators naïve to the USG PB, with moderate experience with ultrasonography and conventional "blind" RB. Both techniques were demonstrated once. Subsequently, operators performed five USG PB and five RB each, unassisted. Contrast location and spread were evaluated by CT. Injection site success was defined for USG PB as extraconal contrast, and for RB intraconal contrast. RESULTS: Success was 10/10 for USG PB and 0/10 for RB (p < 0.001). Of the RB injections, eight resulted in extraconal contrast and two in the masseter muscle (p = 0.47). CONCLUSIONS: The USG PB had a high injection site success rate compared with the RB technique; however, we cannot comment on clinical effect. The USG technique was easily learnt, and no potential complications were seen. The USG PB nerve block could have a wide application for use in horses for ocular surgeries (enucleations, eyelid, corneal, cataract surgeries, and ocular analgesia) due to reduced risk of iatrogenic damage. Further clinical studies are needed.

Validation of a bioabsorbable device that seals perforations after Tuohy needle dural puncture in an ovine model.

BACKGROUND: We designed a device to close accidental dural puncture via the offending puncturing epidural needle directly after diagnosis of the puncture and before removing the needle. The aim of this study was to quantify this device's ability to seal cerebrospinal fluid leakage. METHODS: Forty-six anesthetized adult sheep were studied in a single-blind randomized controlled fashion in two equal groups.An intentional dural puncture was performed with an 18-gage Tuohy needle on all the sheep between L6 and S1 levels. Contrast medium was injected through the needle. Twenty-three animals receive treatment with the sealing device. Two minutes after device placement, or dural puncture in the control group, a CT scan was performed on the animals to estimate contrast material leakage. A region of interest (ROI) was defined as the region that enclosed the subarachnoid space, epidural space, and neuroforaminal canal (the vertebral body above and half of its equivalent height in sacrum below the puncture site). In this region, the total contrast volume and the volumes in the epidural space (EPIDURAL) were measured. The primary outcome measure was the EPIDURAL/ROI ratio to ascertain the proportion of intrathecally injected fluid that passed into the epidural space in both groups. The secondary outcomes were the total amount of contrast in the ROI and the EPIDURAL. RESULTS: The device was deployed successfully in all but two instances, where it suffered from manufacturing defects.Leakage was less in the study group (1.0 vs 1.4 mL, p=0.008). The median EPIDURAL/ROI ratio was likewise less in the study group (29 vs 46; p=0.013; 95% CI (-27 to -3.5)). CONCLUSION: This novel dural puncture-sealing device, also envisaged to be used in other comparable iatrogenic leakage scenarios to be identified in the future, was able to reduce the volume of cerebrospinal fluid that leaked into the epidural space after dural puncture. The device is possibly a valuable way of preventing fluid leakage immediately after the recognition of membrane puncture.

Placental oxygen transfer reduces hypoxia-reoxygenation swings in fetal blood in a sheep model of gestational sleep apnea.

Obstructive sleep apnea (OSA), characterized by events of hypoxia-reoxygenation, is highly prevalent in pregnancy, negatively affecting the gestation process and particularly the fetus. Whether the consequences of OSA for the fetus and offspring are mainly caused by systemic alterations in the mother or by a direct effect of intermittent hypoxia in the fetus is unknown. In fact, how apnea-induced hypoxemic swings in OSA are transmitted across the placenta remains to be investigated. The aim of this study was to test the hypothesis, based on a theoretical background on the damping effect of oxygen transfer in the placenta, that oxygen partial pressure (Po2) swings resulting from obstructive apneas mimicking OSA are mitigated in the fetal circulation. To this end, four anesthetized ewes close to term pregnancy were subjected to obstructive apneas consisting of 25-s airway obstructions. Real-time Po2 was measured in the maternal carotid artery and in the umbilical vein with fast-response fiber-optic oxygen sensors. The amplitudes of Po2 swings in the umbilical vein were considerably smaller [3.1 ± 1.0 vs. 21.0 ± 6.1 mmHg (mean ± SE); P < 0.05]. Corresponding estimated swings in fetal and maternal oxyhemoglobin saturation tracked Po2 swings. This study provides novel insights into fetal oxygenation in a model of gestational OSA and highlights the importance of further understanding the impact of sleep-disordered breathing on fetal and offspring development.NEW & NOTEWORTHY This study in an airway obstruction sheep model of gestational sleep apnea provides novel data on how swings in oxygen partial pressure (Po2) translate from maternal to fetal blood. Real-time simultaneous measurement of Po2 in maternal artery and in umbilical vein shows that placenta transfer attenuates the magnitude of oxygenation swings. These data prompt further investigation of the extent to which maternal apneas could induce similar direct oxidative stress in fetal and maternal tissues.

Comparison of the isoflurane concentration of using dexketoprofen or methadone at premedication during orthopedic surgery in dogs.

Thirty-two dogs were used in this prospective, randomized, clinical and double-blinded study. Dexmedetomidine was administered at 1 µg/kg IV, and randomly each dog received dexketoprofen 1 mg/kg IV (group DK) or methadone 0.2 mg/kg IV (group M). Dogs were induced with propofol and maintained with isoflurane in 100% oxygen. During surgery, the isoflurane concentration was changed depending on clinical signs of depth of anesthesia. Fentanyl and propofol could be used as required. Qualities of sedation and recovery were evaluated. A generalized linear mixed model or Mann-Whiney U test was used, and P<0.05 was considered statistically significant. No significant differences were observed between groups in the qualities of sedation and recovery, isoflurane concentration and in the total amount of fentanyl and propofol used intraoperatively. This study shows that the administration of dexketoprofen at 1 mg/kg IV at premedication required a similar isoflurane concentration to maintain anesthesia as methadone at 0.2 mg/kg IV during orthopedic surgery in dogs. Further analgesia is recommended intraoperatively, because of the need of fentanyl and propofol in same animals in both groups.