Effects of dexmedetomidine on hemodynamic, oxygenation, microcirculation, and inflammatory markers in a porcine model of sepsis

Purpose: To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock. Methods: Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 109 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/ornorepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes. Results: Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m2; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418). Conclusions: Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.

Mechanism of dexmedetomidine preconditioning on spinal cord analgesia in rats with functional chronic visceral pain

Purpose: To analyze the effect and mechanism of dexmedetomidine (DEX) analgesia pretreatment on functional chronic visceral pain in rats. Methods: Rats were divided into six groups: W1, W2, W3, W4, W5, and W6. The behavioral changes and electrophysiological indexes of rats in each group before and after DEX treatment were detected. Results: The levels of abdominal withdrawal reflex (AWR) in W5 and W6 groups were significantly lower than those in group W3, while the levels of thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were significantly higher than those in group W3 (p < 0.05). The electromyographic signals of W1, W5, and W6 groups showed little fluctuation, while those of groups W2, W3, and W4 showed obvious fluctuation. TLR4 mRNA expression, IRF3, P65, and phosphorylation levels in W4, W5, and W6 groups were significantly lower than those in group W2 (p < 0.05). Conclusions: Dexmedetomidine epidural anesthesia pretreatment could significantly inhibit visceral pain response in rats with functional chronic visceral pain, and its mechanism was related to the activation of TLR4 in spinal dorsal horn tissue of rats and the activation inhibition of IRF3 and P65 in the downstream key signals.

Manejo anestésico de um urso pardo (Ursus arctos) cativo submetido a biópsia incisional de nódulo cutâneo / Anesthetic management of a brown bear (Ursus arctos) captive undergoing incisional biopsy of a skin nodule

Background: The brown bear (Ursus arctos) is considered one of the largest terrestrial carnivores, native from temperate forest regions of North America, Europe and Asia. In Brazil, they are founded in captivity and their safe capture and immobilization are obtained with one effective anesthesia for management and surgical and diagnostic procedures. Some anesthetic protocols are described for these purposes, however, there is a lack for data on the anesthetic and adverse effects they have on bears when used. The aim of this case is to report the use and effects of the association of dexmedetomidine with tiletamine and zolazepam in the chemical containment of a captive adult brown bear. Case: A 33-year-old female brown bear, weighing 100 kg, belonging to the Zoobotanic Park of Teresina, Piauí, Brazil, was chemically immobilized for an incisional biopsy of a cutaneous nodule with 1.0 cm diameter in the right face region. The anesthetic protocol included 6 µg/kg of dexmedetomidine associated with 3 mg/kg of tiletamine and zolazepam, administered intramuscularly by dart into the gluteal region of the right pelvic limb. The animal showed moderate ataxia at 5 min and assumed sternal decubitus 7 min after anesthetic administration. The bear's degree of sedation was considered adequate and safe to perform the biopsy at 10 min after administration. Heart rate (47 ± 3 bpm), respiratory rate (17 ± 2 mpm) and rectal temperature (38.7 ± 0.1ºC) were monitored. The bear remained immobile and unconscious throughout the procedure, with intense muscle relaxation, bilateral eyeball rotation, absent lateral palpebral reflex and mild medial reflex and without nystagmus. Complementary sedative doses were not necessary. At the beginning of anesthetic recovery, the bear received 6 µg/kg of atipamezole, intramuscularly. After 25 min of administration of atipamezole, the animal showed signs of recovery in the level of consciousness and reactivity to external stimuli, and assumed the quadrupedal position at 60 min after reverser application. Discussion: Even in captivity, the bears behavior is unpredictable and attack can occur, causing trauma or death to people. For this, the chemical immobilization is important to keep safety of everyone. This procedure was performed using blowgunassisted darts thrown by a staff member who had experience in using this method, who darted accurately and effectively. The latency time observed after administration of the anesthetic protocol used is similar to reported in other studies with bears that also received intramuscular dexmedetomidine and tiletamine and zolazepam and showed intense muscle relaxation and immobility. The doses used contributed to the absence of bradycardia and hypoventilation and, performing the procedure in the morning, when the temperature is milder in the city, minimized the chance of hyperthermia and thermal stress in the animal, not requiring body cooling. The use of dexmedetomidine in chemical containment protocols for short and minimally invasive procedures allows the subsequent use of its antagonist, atipamezole, contributing to a shorter recovery time, return of the animal's degree of consciousness and lower incidence of ataxia after assuming a quadrupedal position. The anesthetic protocol used was considered efficient, providing a quick and gentle chemical containment, adequate anesthetic plan and good anesthetic recovery in an adult brown bear from captivity.

The effect of dexmedetomidine on gastric ischemia reperfusion injury in rats: biochemical and histopathological evaluation

Purpose: To evaluate the protective effect of dexmedetomidine on gastric injury induced by ischemia reperfusion (I/R) in rats. Methods: A total of 18 male albino Wistar rats were divided groups as: gastric ischemia reperfusion (GIR), gastric ischemia reperfusion and 50 g/kg dexmedetomidine (DGIR) and sham operation (HG) group. After the third hour of reperfusion, the biochemical and histopathological examinations were performed on the removed stomach tissue. Results: Malondialdehyde (MDA) and myeloperoxidase (MPO) levels were found to be significantly higher in GIR compared to HG (p 0.05). A statistically significant decrease was observed at the DGIR compared to the GIR for oxidants levels. Total glutathione (tGSH) and superoxide dismutase (SOD) levels were statistically significantly decreased at the GIR, and antioxidants levels were found to be significantly higher in the DGIR (p 0.05) There was no significant difference between HG and DGIR in terms of SOD (p = 0.097). The DGIRs epitheliums, glands and vascular structures were close to normal histological formation. Conclusions: Dexmedetomidine is found to prevent oxidative damage on the stomach by increasing the antioxidant effect. These results indicate that dexmedetomidine may be useful in the treatment of ischemia-reperfusion-related gastric damage.(AU)

Anestesia geral em jabuti-piranga (Chelonoides carbonaria) para retirada de corpo estranho gástrico / General anesthesia in red-footed tortoise (Chelonoides carbonaria) for gastric foreign body removal

Background: The anatomical, physiological, and pharmacological characteristics of reptiles make anesthesia in chelonians particularly challenging. Specific literature regarding safe anesthetic protocols that provide immobilization, antinociception, amnesia, and unconsciousness are scarce. Thus, this paper aims to report the case of a red-footed tortoise submitted to long-duration general anesthesia to celiotomy for foreign body removal. Case: An adult red-footed tortoise (Chelonoides carbonaria), 5.9 kg, was admitted due to hyporexia after ingesting a metallic fishhook. Serial radiographs confirmed the diagnosis and location of the foreign body in the stomach. The animal was premedicated with 0.03 mg/kg dexmedetomidine, 6 mg/kg ketamine, and 0.4 mg/kg butorphanol intramuscularly. After 90 min we inserted a 22G jugular catheter and proceeded to anesthesia induction with 5 mg/kg propofol. We intubated the animal with a 2.5 mm uncuffed endotracheal and started fluid therapy at a rate of 5 mL/kg/h. Surgical anesthesia was maintained with isoflurane in 0.21 oxygen, in a non-rebreathing circuit (baraka), under spontaneous breathing. Expired isoflurane was maintained between 3 and 4.5%. Due to reduced respiratory rate and hypercapnia, we opted for implementing manually-assisted positive pressure ventilation. Morphine (0.5 mg/kg) was administered at 10 and 87 min after the beginning of the surgery for further analgesia when the isoflurane requirement increased significantly. We did not detect any alterations in heart and body temperature. Surgical anesthesia lasted 6 h. During anesthesia recovery, voluntary head retraction and coordinated movement of the limbs occurred at 240 and 540 min after the extubation, respectively. In 2 days, the patient returned to voluntary feeding, being very active and responsive to stimulus. The post-surgical hematologic evaluation was unremarkable. Discussion: Pre-anesthetic medication aimed to promote sedation and preemptive analgesia. Due to its minimal cardiorespiratory depression, we chose the combination of ketamine, dexmedetomidine, and butorphanol. Dexmedetomidine reduced the ketamine dose and caused sufficient muscle relaxation and immobilization to perform the jugular catheter placement. Butorphanol is an agonist-antagonist opioid; that is why we decided to add it to the protocol for antinociception. However, due to signs of nociceptive response (increased isoflurane requirements and heart rate), and considering the evidence of a predominance of µ receptors in reptiles, we administered low-dose morphine twice during the procedure. Propofol was chosen as an induction agent at a dose sufficient to allow endotracheal intubation. Since reptilians often show apnea in the presence of 100% oxygen, we used a 0.21 oxygen fraction. Despite this, the patient showed respiratory depression. Due to right to left cardiac shunt, sudden changes in the direction of the blood can lead to very rapid changes in the serum concentrations of isoflurane, which leads to frequent oscillations in the anesthetic depth and consequently the need for vaporizer adjustments, which may justify the high expired isoflurane fraction during the procedure. Despite that, physiological parameters were maintained within normal ranges for the species, with slight variations during the surgical procedure. We conclude that the proposed anesthetic protocol is safe for long-duration anesthesia in chelonians, ensuring cardiovascular and respiratory stability. Thus, this report may help veterinarians to perform safe anesthesia in tortoises submitted to invasive surgical procedures.

The outcomes of dexmedetomidine and calcitriol on flap viability

Purpose: To evaluate protective effects of dexmedetomidine, calcitriol and their combination. Methods: Forty Wistar-albino rats were divided into 4 groups; group of Sham (Group Sham); group of dexmedetomidine (Group DEX); group of calcitriol (Group CAL) and group of dexmedetomidineandcalcitriol (Group DEX-CAL). Photographic analysis was used for macroscopic analysis and perfusion analyses were evaluated by scintigraphy. Additionally, tissue malondialdehyde (MDA) and total oxidant status (TOS) and total antioxidant activity (TAS) were recorded and oxidative stress index (OSI) was calculated. Each flap was assessed by histopathology. Results: Compared to Group Sham, the viable flap areas were higher in all treatment groups both by photographic image analyses and perfusion analyses (p 0.05). Group DEX-CAL had the highest viable flap percentage both in scintigraphic and photographic analyses; whereas Group Sham had the lowest viable flap percentage. Similarly, TAS and MDA levels were elevated and TOS levels were declined in all treatment groups compared to Group Sham (p 0.005). Histopathological analysis at flap demarcation zone confirmed neovascularization was significantly higher and edema, necrosis and inflammation were significantly lower in all treatment groups compared to Group Sham. Conclusion: The outcomes show that additional premedication with either dexmedetomidine or calcitriol or their combination reduces ischemia-reperfusion injury of flap area and show significant increase in the percentage of viable flap tissue.(AU)

Anestesia multimodal em cachorro-do-mato (Cerdocyon thous) submetido à hemilaminectomia e estabilização sacrococcígea / Multimodal anaesthesia in a crab-eating fox (Cerdocyon thous) undergoing hemilaminectomy and sacrococcygeal stabilization

Background: Several researches have shown the impacts of roads more directly to wildlife in Brazil. The crab-eating fox(Cerdocyon thous) is a frequent run over victim. Dissociative drugs are commonly used, but inhalation anesthesia is indicatedin cases of extensive and prolonged surgeries. Despite their similarity with domestic dogs, the literature is scarce regarding theassociation of new anesthetic techniques and protocols in wild canids. The aim of this paper was to report the viability of multimodal anesthesia in a crab-eating fox, victim of running over, undergoing hemilaminectomy and sacrococcygeal stabilization.Case: An adult male specimen of crab-eating fox was rescued after being run over and taken to a wild animal screening center.Physical examination showed superficial and deep pain, lack of support for the pelvic limbs and proprioception, increasedreflexes, and reduced tail mobility. Chemical restraint with intramuscular (IM) tiletamine-zolazepam (6.0 mg/kg) and morphine (0.5 mg/kg) was performed. Meloxicam (0.2 mg/kg IM) and enrofloxacin (5.0 mg/kg IM) were also administered. Theanimal was sequentially admitted to the veterinary hospital. Radiographic images showed compaction of the spinal columnof the T10 and T11 thoracic vertebrae and the sacrococcygeal region. Sixty min after chemical restraint, the anesthesia wassupplemented with IM tiletamine-zolazepam (4.5 mg/kg), and fluid therapy with 0.9% NaCl (10 mL/kg/h) was started. Ten minlater, intravenous propofol dose-effect (2.5 mg/kg) was administered and general anesthesia was maintained with isoflurane(FiO2 = 1.0). Thirty min after the induction of anesthesia, the animal was urdergoing hemilaminectomy and sacrococcygealstabilization. Constant rate infusions (CRI) of dexmedetomidine (0.5 μg/kg/h) and ketamine (0.6 mg/kg/h) were started. Lidocaine (7.0 mg/kg) and bupivacaine (2.0 mg/kg) were administered into the surgical site on the T10 and T11 vertebrae at 35...(AU)

Anestesia multimodal em cachorro-do-mato (Cerdocyon thous) submetido à hemilaminectomia e estabilização sacrococcígea / Multimodal anaesthesia in a crab-eating fox (Cerdocyon thous) undergoing hemilaminectomy and sacrococcygeal stabilization

Background: Several researches have shown the impacts of roads more directly to wildlife in Brazil. The crab-eating fox(Cerdocyon thous) is a frequent run over victim. Dissociative drugs are commonly used, but inhalation anesthesia is indicatedin cases of extensive and prolonged surgeries. Despite their similarity with domestic dogs, the literature is scarce regarding theassociation of new anesthetic techniques and protocols in wild canids. The aim of this paper was to report the viability of multimodal anesthesia in a crab-eating fox, victim of running over, undergoing hemilaminectomy and sacrococcygeal stabilization.Case: An adult male specimen of crab-eating fox was rescued after being run over and taken to a wild animal screening center.Physical examination showed superficial and deep pain, lack of support for the pelvic limbs and proprioception, increasedreflexes, and reduced tail mobility. Chemical restraint with intramuscular (IM) tiletamine-zolazepam (6.0 mg/kg) and morphine (0.5 mg/kg) was performed. Meloxicam (0.2 mg/kg IM) and enrofloxacin (5.0 mg/kg IM) were also administered. Theanimal was sequentially admitted to the veterinary hospital. Radiographic images showed compaction of the spinal columnof the T10 and T11 thoracic vertebrae and the sacrococcygeal region. Sixty min after chemical restraint, the anesthesia wassupplemented with IM tiletamine-zolazepam (4.5 mg/kg), and fluid therapy with 0.9% NaCl (10 mL/kg/h) was started. Ten minlater, intravenous propofol dose-effect (2.5 mg/kg) was administered and general anesthesia was maintained with isoflurane(FiO2 = 1.0). Thirty min after the induction of anesthesia, the animal was urdergoing hemilaminectomy and sacrococcygealstabilization. Constant rate infusions (CRI) of dexmedetomidine (0.5 μg/kg/h) and ketamine (0.6 mg/kg/h) were started. Lidocaine (7.0 mg/kg) and bupivacaine (2.0 mg/kg) were administered into the surgical site on the T10 and T11 vertebrae at 35...

Protective efficacy of combined use of parecoxib and dexmedetomidine on postoperative hyperalgesia and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients

Purpose:To investigate efficacy of combined use of parecoxib and dexmedetomidine on postoperative pain and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients.Methods:The present prospective randomized controlled study included a total of 80 patients who underwent laparoscopic cholecystectomy surgery during January 2016 to November 2017 in our hospital. All patients were randomly divided into 4 groups, the parecoxib group, the dexmedetomidine group, the parecoxib and dexmedetomidine combined group, and the control group. Demographic data and clinical data were collected. Indexes of heart rate (HR), mean arterial pressure (MAP), levels of jugular venous oxygen saturation (SjvO2) and jugular venous oxygen pressure (PjvO2) were recorded at different time points before and during the surgery. The mini-mental state examination (MMSE) score, Ramsay score and Visual Analogue Score (VAS) were measured.Results:Levels of both SjvO2 and PjvO2 were significantly higher in parecoxib group, dexmedetomidine group and the combined group than the control group. Meanwhile, levels of both SjvO2 and PjvO2 in the combined group were the highest. VAS scores were significantly lower in the combined group than all other groups, and total patient controlled intravenous analgesia (PCIA) pressing times within 48 h after surgery were the lowest in the combined group. Both Ramsay and MMSE scores were the highest in the combined group compared with other groups, while were the lowest in the control group.Conclusion:The combined use of parecoxib and dexmedetomidine could reduce the postoperative pain and improve the postoperative sedation and cognitive conditions of patients after laparoscopic cholecystectomy.(AU)

Anestesia geral em Sapajus nigritus (Macaco-prego) / General anesthesia in Sapajus nigritus (black capuchin)

Background: The black capuccin (Sapajus nigritus) is one of the most abundant primate specimens in Brazil. Amongpopulation control techniques, vasectomy can be used once it maintains the animals leading behavior in the group throughhormonal presence, production of spermatogenic series, and copula. However, due to their escape behavior, agitation, inaddition to the impossibility of knowing the physiological state of these animals beforehand, their capture poses a considerable challenge. Thus, chemical restraint is indispensable and the use of effective and safe anesthetic protocols to animalintegrity is of paramount importance. In this scenario, the present study aims to report the anesthesia of a black capuccinsubmitted to vasectomy.Case: A 1-year-old male, 1.1 kg monkey (Sapajus nigritus) was admitted at a Veterinary Hospital after being found onthe ground in a natural reserve in the town of Assis Chateaubriand, in the west of Parana State. After clinical evaluation,the patient was submitted to vasectomy as a birth control method, before his return to the natural area, which presentedoverpopulation of the species. After preanesthetic examinations, the animal was considered healthy, and thus, premedicatedwith the combination of dexmedetomidine (10 μg/kg) and ketamine (10 mg/kg), intramuscularly. Anesthetic inductionwith propofol was performed to effect. Laringeal desensitization was achieved with 2% lidocaine (2 mg/kg), which allowed orotracheal intubation through direct visualization. Anesthesia was maintained with 1% isoflurane in a 0.5 oxygenfraction and spontaneous ventilation using a non-rebreathing circuit. The spermatic cord and the skin were desensitizedwith lidocaine (4 mg/kg). During the procedure, the animal was monitored for pulse oximetry, electrocardiogram, systolicblood pressure, body temperature, end tidal CO2 (ETCO2), and end tidal isoflurane. The animal also received 10 mL/kg/h ringer...(AU)

Anestesia geral em Sapajus nigritus (Macaco-prego) / General anesthesia in Sapajus nigritus (black capuchin)

Background: The black capuccin (Sapajus nigritus) is one of the most abundant primate specimens in Brazil. Amongpopulation control techniques, vasectomy can be used once it maintains the animal’s leading behavior in the group throughhormonal presence, production of spermatogenic series, and copula. However, due to their escape behavior, agitation, inaddition to the impossibility of knowing the physiological state of these animals beforehand, their capture poses a considerable challenge. Thus, chemical restraint is indispensable and the use of effective and safe anesthetic protocols to animalintegrity is of paramount importance. In this scenario, the present study aims to report the anesthesia of a black capuccinsubmitted to vasectomy.Case: A 1-year-old male, 1.1 kg monkey (Sapajus nigritus) was admitted at a Veterinary Hospital after being found onthe ground in a natural reserve in the town of Assis Chateaubriand, in the west of Parana State. After clinical evaluation,the patient was submitted to vasectomy as a birth control method, before his return to the natural area, which presentedoverpopulation of the species. After preanesthetic examinations, the animal was considered healthy, and thus, premedicatedwith the combination of dexmedetomidine (10 μg/kg) and ketamine (10 mg/kg), intramuscularly. Anesthetic inductionwith propofol was performed to effect. Laringeal desensitization was achieved with 2% lidocaine (2 mg/kg), which allowed orotracheal intubation through direct visualization. Anesthesia was maintained with 1% isoflurane in a 0.5 oxygenfraction and spontaneous ventilation using a non-rebreathing circuit. The spermatic cord and the skin were desensitizedwith lidocaine (4 mg/kg). During the procedure, the animal was monitored for pulse oximetry, electrocardiogram, systolicblood pressure, body temperature, end tidal CO2 (ETCO2), and end tidal isoflurane. The animal also received 10 mL/kg/h ringer...

Avaliação da analgesia pós-operatória da dexmedetomidina isolada e associada à morfina quando utilizada na medicação pré-anestésica em cadelas submetidas à ovariosalpingohisterectomia eletiva / Evaluation of postoperative analgesia of dexmedetomidine alone or associated to morphine as premedicants in bitches undergoing ovariosalpingohisterectomy

Background: Elective ovariossalpingohysterectomy is a common surgery that causes mild to moderate pain. Aiming at the treatment of pain in these patients, analgesia should be balanced from pre-anesthetic, transoperative and postoperative medication, with-2-agonists and opioids being commonly used, especially dexmedetomidine that has sedation, relaxation muscle and analgesia.The aim of the present study was to evaluate the postoperative analgesic efficacy of dexmedetomidine alone and associated withmorphine when used in the preanesthetic medication of bitches submitted to elective ovarian oysterectomy using the modifiedGlasgow pain scale and the Melbourne pain scale.Materials, Methods & Results: Twenty bitches were used in this study, all of them submitted to ovarian oysterectomy, and were clinically healthy according to laboratory and clinical exams. During the experiment, bitches were randomly distributed into two groups,which received preanesthetic medication (MPA) with 5 μg/kg dexmedetomidine alone (GD) or associated with 0.3 mg/kg morphine(GDM) intramuscularly (IM). In both groups, anesthetic induction with dose-effect propofol was performed and maintained withisoflurane diluted in 100% oxygen administered through a calibrated vaporizer and appropriate anesthetic system based on the weightof the animal and maintained on spontaneous ventilation. After stabilization of the patient the surgery was started, which lasted 45min. The bitches were evaluated by the Modified Glasgow Scale (GSM), the Melbourne Scale (MS) and the Dobbins Sedation Scale(DS), previously administered MPA (T0) and the others performed in 1h (T1), 2h (T2), 4h (T3), 8h (T4), 12h (T5) and 24h (T6) afterextubation. If the GSM score was greater than the value of 3.3 an analgesic rescue of 0.5 mg/kg of morphine intramuscularly would beadministered. An increase in the scoring of pain scales in both groups can be observed from the T1, with significant difference only ofthe...(AU)

Avaliação da analgesia pós-operatória da dexmedetomidina isolada e associada à morfina quando utilizada na medicação pré-anestésica em cadelas submetidas à ovariosalpingohisterectomia eletiva / Evaluation of postoperative analgesia of dexmedetomidine alone or associated to morphine as premedicants in bitches undergoing ovariosalpingohisterectomy

Background: Elective ovariossalpingohysterectomy is a common surgery that causes mild to moderate pain. Aiming at the treatment of pain in these patients, analgesia should be balanced from pre-anesthetic, transoperative and postoperative medication, with-2-agonists and opioids being commonly used, especially dexmedetomidine that has sedation, relaxation muscle and analgesia.The aim of the present study was to evaluate the postoperative analgesic efficacy of dexmedetomidine alone and associated withmorphine when used in the preanesthetic medication of bitches submitted to elective ovarian oysterectomy using the modifiedGlasgow pain scale and the Melbourne pain scale.Materials, Methods & Results: Twenty bitches were used in this study, all of them submitted to ovarian oysterectomy, and were clinically healthy according to laboratory and clinical exams. During the experiment, bitches were randomly distributed into two groups,which received preanesthetic medication (MPA) with 5 μg/kg dexmedetomidine alone (GD) or associated with 0.3 mg/kg morphine(GDM) intramuscularly (IM). In both groups, anesthetic induction with dose-effect propofol was performed and maintained withisoflurane diluted in 100% oxygen administered through a calibrated vaporizer and appropriate anesthetic system based on the weightof the animal and maintained on spontaneous ventilation. After stabilization of the patient the surgery was started, which lasted 45min. The bitches were evaluated by the Modified Glasgow Scale (GSM), the Melbourne Scale (MS) and the Dobbins Sedation Scale(DS), previously administered MPA (T0) and the others performed in 1h (T1), 2h (T2), 4h (T3), 8h (T4), 12h (T5) and 24h (T6) afterextubation. If the GSM score was greater than the value of 3.3 an analgesic rescue of 0.5 mg/kg of morphine intramuscularly would beadministered. An increase in the scoring of pain scales in both groups can be observed from the T1, with significant difference only ofthe...

Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain

Purpose: To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP). Methods: The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity. Results: Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively). Conclusion: The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.(AU)

Bloqueio do plexo braquial com uso de neuroestimulador em coruja-orelhuda (Asio clamator) submetida à amputação de asa / Brachial plexus block with use of a neurostimulator in a striped owl (Asio clamator) undergoing wing amputation

Background: The use of distinct drugs and techniques for establishing balanced anesthesia protocols has shown promisingresults in birds. The techniques of locoregional block can be incorporated to these protocols, thereby providing intra- andpost-operative analgesia and reducing the requirement for general anesthesia. Additionally, the use of neurostimulatorsincreases the chances of success and reduces the risk of toxicity; however, there are limited reports in the literature of itsapplicability in wild birds. Therefore, the aim of this study was to describe the brachial plexus block technique guidedusing a neurolocalizer in a striped owl (Asio clamator) submitted for right wing amputation.Case: A striped owl weighing 400 g with a history of exposed fracture of the right wing was supplied by the clinical sectorat the Veterinarian Hospital of the Federal University of Bahia. Following hydration and stabilization of vital signs, theanimal was referred to the surgical center for amputation of the limb. Dexmedetomidine (10 µg.kg−1 IM) was administeredas premedication, and after 20 min, anesthetic induction was performed using sevoflurane (FiO2 = 100%) via a mask followed by maintenance using the same drug. The animal was positioned in a left lateral decubitus position with access to thebrachial plexus determined by palpation and identification of the border of the following muscles: pectoral, cranial branchof the brachial biceps, and dorsal branch of the ventral serratus. The brachial plexus nerves are situated in the subcutaneous site craniodorsal to the axillary depression. For the block, a neurolocalizer was used, fixing the positive electrode toapproximately 5 cm from the needle insertion site (21G × 2’”) in the axillary depression, which remained connected to theneurostimulator by the second electrode. At first, the needle was attached to the peripheral nerve stimulator using a pulsefrequency of 1 Hz with an...

Bloqueios dos nervos ciático e femoral guiado por neuroestimulador em Chinchilla lanigera submetida a osteossíntese de tíbia / Nerve stimulator-guided ciatic and femoral nerve block during tibial osteosynthesis in Chinchilla lanigera

Background: Nociceptive stimulation in orthopedic surgery requires effective pain management to ensure trans andpostoperative patient comfort. Several techniques can be used for this, and multimodal analgesia protocols such as guidedlocoregional blocks provide a balanced effect, as they enable the use of low-dose anesthetics and offer rapid recovery. Thebenefits of specific nerve blocks in domestic animals are well known; however, there are few reports that have ascertainedtheir safety in wild species. This report is aimed at describing the successful use of neurolocalizer-guided sciatic andfemoral nerve blocks during tibial osteosyntheses in a chinchilla.Case: A 9-month-old chinchilla weighing 0.56 kg was referred for surgery for proximal and mid-diaphyseal tibia fracturesresulting from trauma. Following preanesthetic evaluation, the animal received intramuscular dexmedetomidine (15 µgkg1) as preanesthetic medication. Sedation was apparent after 15 min and was verified by a decreased activity, the animalallowing manipulation, absence of the eyelid and righting reflexes, and limb movement after clamping removal of limbafter clamping. After achieving sedation, anesthesia was induced and maintained with sevoflurane (FiO2 = 1.0), suppliedthrough a nasoral mask. Sciatic and femoral nerve blocks were performed with the aid of a neurostimulator. A needle wasinserted into the femoral triangle, cranial to the femoral artery, and into the depression between the sciatic tuberosity andthe greater femoral trochanter. The neurostimulator was set at a pulse frequency of 1 Hz, pulse duration of 0.1 ms andinitial current of 0.6 mA. The needle was advanced toward the nerves until muscle contractions were observed, and thecurrent was gradually reduced until contractions were manifested at a minimum current...

Bloqueios dos nervos ciático e femoral guiado por neuroestimulador em Chinchilla lanigera submetida a osteossíntese de tíbia / Nerve stimulator-guided ciatic and femoral nerve block during tibial osteosynthesis in Chinchilla lanigera

Background: Nociceptive stimulation in orthopedic surgery requires effective pain management to ensure trans andpostoperative patient comfort. Several techniques can be used for this, and multimodal analgesia protocols such as guidedlocoregional blocks provide a balanced effect, as they enable the use of low-dose anesthetics and offer rapid recovery. Thebenefits of specific nerve blocks in domestic animals are well known; however, there are few reports that have ascertainedtheir safety in wild species. This report is aimed at describing the successful use of neurolocalizer-guided sciatic andfemoral nerve blocks during tibial osteosyntheses in a chinchilla.Case: A 9-month-old chinchilla weighing 0.56 kg was referred for surgery for proximal and mid-diaphyseal tibia fracturesresulting from trauma. Following preanesthetic evaluation, the animal received intramuscular dexmedetomidine (15 µgkg1) as preanesthetic medication. Sedation was apparent after 15 min and was verified by a decreased activity, the animalallowing manipulation, absence of the eyelid and righting reflexes, and limb movement after clamping removal of limbafter clamping. After achieving sedation, anesthesia was induced and maintained with sevoflurane (FiO2 = 1.0), suppliedthrough a nasoral mask. Sciatic and femoral nerve blocks were performed with the aid of a neurostimulator. A needle wasinserted into the femoral triangle, cranial to the femoral artery, and into the depression between the sciatic tuberosity andthe greater femoral trochanter. The neurostimulator was set at a pulse frequency of 1 Hz, pulse duration of 0.1 ms andinitial current of 0.6 mA. The needle was advanced toward the nerves until muscle contractions were observed, and thecurrent was gradually reduced until contractions were manifested at a minimum current...(AU)

Bloqueio do plexo braquial com uso de neuroestimulador em coruja-orelhuda (Asio clamator) submetida à amputação de asa / Brachial plexus block with use of a neurostimulator in a striped owl (Asio clamator) undergoing wing amputation

Background: The use of distinct drugs and techniques for establishing balanced anesthesia protocols has shown promisingresults in birds. The techniques of locoregional block can be incorporated to these protocols, thereby providing intra- andpost-operative analgesia and reducing the requirement for general anesthesia. Additionally, the use of neurostimulatorsincreases the chances of success and reduces the risk of toxicity; however, there are limited reports in the literature of itsapplicability in wild birds. Therefore, the aim of this study was to describe the brachial plexus block technique guidedusing a neurolocalizer in a striped owl (Asio clamator) submitted for right wing amputation.Case: A striped owl weighing 400 g with a history of exposed fracture of the right wing was supplied by the clinical sectorat the Veterinarian Hospital of the Federal University of Bahia. Following hydration and stabilization of vital signs, theanimal was referred to the surgical center for amputation of the limb. Dexmedetomidine (10 µg.kg−1 IM) was administeredas premedication, and after 20 min, anesthetic induction was performed using sevoflurane (FiO2 = 100%) via a mask followed by maintenance using the same drug. The animal was positioned in a left lateral decubitus position with access to thebrachial plexus determined by palpation and identification of the border of the following muscles: pectoral, cranial branchof the brachial biceps, and dorsal branch of the ventral serratus. The brachial plexus nerves are situated in the subcutaneous site craniodorsal to the axillary depression. For the block, a neurolocalizer was used, fixing the positive electrode toapproximately 5 cm from the needle insertion site (21G × 2”) in the axillary depression, which remained connected to theneurostimulator by the second electrode. At first, the needle was attached to the peripheral nerve stimulator using a pulsefrequency of 1 Hz with an... (AU)

Sedative and electrocardiographic effects of low dose dexmedetomidine in healthy cats / Efeitos sedativos e eletrocardiográficos da baixa dose de dexmedetomidina em gatos saudáveis

In feline veterinary practice sedation is often needed to perform diagnostic or minimally invasive procedures, minimize stress, and facilitate handling. The mortality rate of cats undergoing sedation is significantly higher than dogs, so it is fundamental that the sedatives provide good cardiovascular stability. Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist utilized in cats to provide sedation and analgesia, although studies have been utilized high doses, and markedly hemodynamic impairments were reported. The aim of this study was to prospectively investigate how the sedative and electrocardiographic effects of a low dose of DEX performing in cats. Eleven healthy cats were recruited; baseline sedative score, systolic arterial pressure, electrocardiography, and vasovagal tonus index (VVTI) were assessed, and repeated after ten minutes of DEX 5μg/kg intramuscularly (IM). A smooth sedation was noticed, and emesis and sialorrhea were common adverse effects, observed on average seven minutes after IM injection. Furthermore, electrocardiographic effects of a low dose of DEX mainly include decreases on heart rate, and increases on T-wave amplitude. The augmentation on VVTI and appearance of respiratory sinus arrhythmia, as well as sinus bradycardia in some cats, suggesting that DEX enhances parasympathetic tonus in healthy cats, and therefore will be best avoid in patients at risk for bradycardia.(AU)

Na rotina clínica da medicina veterinária felina a sedação é frequentemente requerida para realização de procedimentos diagnósticos ou minimamente invasivos, para minimizar o estresse e facilitar o manuseio dos pacientes. A taxa de mortalidade de gatos submetidos à sedação é mais elevada do que em cães, por esse motivo, é fundamental que os sedativos confiram estabilidade hemodinâmica. A dexmedetomidina (DEX) é um α2-agonista utilizado em felinos para promover sedação e analgesia, porém os estudos têm utilizado doses elevadas, e com isso prejuízos hemodinâmicos importantes foram relatados. O objetivo desta investigação foi avaliar os efeitos sedativos e eletrocardiográficos da baixa dose de DEX em gatos. Para tal, onze felinos saudáveis foram recrutados, foram obtidos valores basais para escore de sedação, pressão arterial sistólica e eletrocardiografia, além do índice de tônus vaso vagal (ITVV). Após dez minutos da aplicação intramuscular (IM) de DEX 5μg/kg todos os exames foram repetidos. Após a DEX, sedação suave foi detectada, e a êmese e sialorreia foram efeitos adversos comuns, observados em média 7 minutos após a injeção IM. Ademais, os principais efeitos eletrocardiográficos foram redução na frequência cardíaca e aumento na amplitude da onda T. O ITVV mais elevado e surgimento de arritmia sinusal respiratória, bem como bradicardia sinusal em alguns gatos, sugerem que a DEX eleva o tônus parassimpático, e por esse motivo deve ser utilizada com cautela em pacientes com predisposição à bradicardia.(AU)

Sedative and electrocardiographic effects of low dose dexmedetomidine in healthy cats / Efeitos sedativos e eletrocardiográficos da baixa dose de dexmedetomidina em gatos saudáveis

In feline veterinary practice sedation is often needed to perform diagnostic or minimally invasive procedures, minimize stress, and facilitate handling. The mortality rate of cats undergoing sedation is significantly higher than dogs, so it is fundamental that the sedatives provide good cardiovascular stability. Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist utilized in cats to provide sedation and analgesia, although studies have been utilized high doses, and markedly hemodynamic impairments were reported. The aim of this study was to prospectively investigate how the sedative and electrocardiographic effects of a low dose of DEX performing in cats. Eleven healthy cats were recruited; baseline sedative score, systolic arterial pressure, electrocardiography, and vasovagal tonus index (VVTI) were assessed, and repeated after ten minutes of DEX 5μg/kg intramuscularly (IM). A smooth sedation was noticed, and emesis and sialorrhea were common adverse effects, observed on average seven minutes after IM injection. Furthermore, electrocardiographic effects of a low dose of DEX mainly include decreases on heart rate, and increases on T-wave amplitude. The augmentation on VVTI and appearance of respiratory sinus arrhythmia, as well as sinus bradycardia in some cats, suggesting that DEX enhances parasympathetic tonus in healthy cats, and therefore will be best avoid in patients at risk for bradycardia.(AU)

Na rotina clínica da medicina veterinária felina a sedação é frequentemente requerida para realização de procedimentos diagnósticos ou minimamente invasivos, para minimizar o estresse e facilitar o manuseio dos pacientes. A taxa de mortalidade de gatos submetidos à sedação é mais elevada do que em cães, por esse motivo, é fundamental que os sedativos confiram estabilidade hemodinâmica. A dexmedetomidina (DEX) é um α2-agonista utilizado em felinos para promover sedação e analgesia, porém os estudos têm utilizado doses elevadas, e com isso prejuízos hemodinâmicos importantes foram relatados. O objetivo desta investigação foi avaliar os efeitos sedativos e eletrocardiográficos da baixa dose de DEX em gatos. Para tal, onze felinos saudáveis foram recrutados, foram obtidos valores basais para escore de sedação, pressão arterial sistólica e eletrocardiografia, além do índice de tônus vaso vagal (ITVV). Após dez minutos da aplicação intramuscular (IM) de DEX 5μg/kg todos os exames foram repetidos. Após a DEX, sedação suave foi detectada, e a êmese e sialorreia foram efeitos adversos comuns, observados em média 7 minutos após a injeção IM. Ademais, os principais efeitos eletrocardiográficos foram redução na frequência cardíaca e aumento na amplitude da onda T. O ITVV mais elevado e surgimento de arritmia sinusal respiratória, bem como bradicardia sinusal em alguns gatos, sugerem que a DEX eleva o tônus parassimpático, e por esse motivo deve ser utilizada com cautela em pacientes com predisposição à bradicardia.(AU)