Use of orally administered dexmedetomidine to induce emesis in cats.

CASE SERIES SUMMARY: This case series describes the use of orally administered dexmedetomidine at a dose of 20 µg/kg to induce emesis in six cats. Emesis was successfully induced in 5/6 cats, with each of the cats vomiting once. The reasons for inducing vomiting included known or suspected ingestion of lilies, onions, acetaminophen (paracetamol) or acetylsalicylic acid. Four of the five cats in which emesis induction was successful did not develop any clinical signs of toxicity associated with the toxin ingested; the fifth cat developed clinicopathological changes consistent with acetaminophen toxicity. All six cats exhibited moderate to profound sedation, as expected, but no other adverse effects were documented. RELEVANCE AND NOVEL INFORMATION: Induction of emesis in cats is notoriously difficult. This case series describes a novel route of administration of dexmedetomidine, a commonly available medication, with a high success rate observed for inducing emesis in this group of cats.

Cats are notoriously more difficult to elicit vomiting in than dogs. This case series describes the use of a novel way of giving cats a commonly available veterinary medication to cause vomiting. The medication, dexmedetomidine, was given by mouth to six cats, of which five vomited. All six cats had eaten toxins: lilies, acetaminophen (paracetamol), aspirin or onions. Four of the five cats that vomited did not develop any signs of toxicity. All six cats that received the medication became sedated, but no other side effects were noted.

Effect of Intravenous Dexmedetomidine Before Extubation on Emergence Delirium after Nasal Surgeries.

OBJECTIVE: To investigate the role of single dose of dexmedetomidine (0.5 mcg/kg) in reducing the incidence and severity of postoperative emergence delirium (EmD). STUDY DESIGN: A randomised controlled trial. Place and Duration of the Study: Department of Anaesthesia, Security Forces Hospital, Riyadh, Saudi Arabia, from 1st December 2022 to 30th March 2023. METHODOLOGY: Patients, aged between 18-65 years, with ASA 1-3 scheduled to undergo nasal surgeries under general anaesthesia, were inducted in the study. Exclusion criteria were patient refusal, later request for removal from the study, inability to give consent, known allergy to dexmedetomidine, body mass index (BMI) more than 35, history of obstructive sleep apnoea, history of psychiatric illness, pregnancy, and presence of liver and renal diseases. The primary outcome measure of the study was the incidence of emergence delirium in the postoperative period. RESULTS: The frequency of EmD after nasal surgery was 52.38% in the control group compared to 14.28% in the dexmedetomidine group (p = 0.01). Pain scores were not statistically different between the two groups. The duration of post anaesthesia care unit (PACU) stay was significantly lesser in dexmedetomidine group (p <0.001). The satisfaction score on the visual analogue scale (VAS) was also found to be higher in patients who received intravenous dexmedetomidine (p <0.001). CONCLUSION: The use of single dose dexmedetomidine before extubation in nasal surgeries reduces the EmD and improves patient satisfaction. KEY WORDS: Dexmedetomidine, Emergence delirium, Nasal surgery, Opioid consumption, Pain control.

Impact of intraoperative dexmedetomidine on postoperative delirium and pro-inflammatory cytokine levels in elderly patients undergoing thoracolumbar compression fracture surgery: A prospective, randomized, placebo-controlled clinical trial.

BACKGROUND: This study evaluates the efficacy of dexmedetomidine (DEX) in reducing postoperative delirium (POD) and modulating pro-inflammatory cytokines in elderly patients undergoing thoracolumbar compression fracture surgery. METHODS: In this randomized, double-blind, placebo-controlled trial conducted from October 2022 to January 2023 at Anting Hospital in Shanghai, 218 elderly patients were randomized into DEX (n = 110) and normal saline (NS, n = 108) groups. The DEX group received 0.5 µg/kg/h DEX, and delirium incidence was assessed using the Confusion Assessment Method (CAM) on days 1 to 3 post-surgery. Levels of interleukins IL-1ß, IL-6, and tumor necrosis factor-α (TNF-α) were measured pre-operation (T0) and on postoperative days 1 (T1) and 3 (T3). Preoperative (T0) and postoperative day 1 (T1) cerebrospinal fluid (CSF) samples were treated with varying concentrations of olanzapine or DEX to observe their regulatory effects on the expression of Phospho-ERK1/2 and Phospho-JNK. RESULTS: Dexmedetomidine significantly lowered the incidence of POD to 18.2%, compared to 30.6% in the NS group (P = .033). While all patients showed an initial increase in cytokine levels after surgery, by T3, IL-6 and TNF-α levels notably decreased in the DEX group, with no significant change in IL-1ß levels across groups. The adverse events rate was similar between groups, demonstrating the safety of DEX in this population. In postoperative CSF samples, treatment with 0.5 mM DEX significantly downregulated Phospho-JNK and upregulated Phospho-ERK1/2 expression, demonstrating a dose-dependent modulation of inflammatory responses. CONCLUSION: Dexmedetomidine is effective in reducing early POD in elderly patients post-thoracolumbar compression fracture surgery. It also decreases IL-6 and TNF-α levels, indicating its potential in managing postoperative inflammatory responses. Treatment with 0.5 mM DEX significantly modulated Phospho-ERK1/2 and Phospho-JNK expressions in postoperative CSF samples, indicating a dose-dependent effect on reducing inflammation. This study contributes to understanding DEX's role in improving postoperative outcomes in elderly patients.

Application of intranasal dexmedetomidine in magnetic resonance imaging of preterm infants: The ED50, efficacy and safety analysis.

BACKGROUND: Infants undergoing magnetic resonance imaging (MRI) often require pharmacological sedation. Dexmedetomidine serves as a novel sedative agent that induces a unique unconsciousness similar to natural sleep, and therefore has currently been used as the first choice for sedation in infants and young children. OBJECTIVE: To determine the 50% effective dose (ED50) and 95% confidence interval (95%CI) of intranasal dexmedetomidine for MRI in preterm and term infants, and to observe the incidence of adverse events. To explore whether there were differences in ED50 and 95%CI, heart rate (HR) and blood oxygen saturation (SpO2), the induction time and wake-up time and the incidence of adverse events between the 2 groups, so as to provide guidance for clinical safe medication for the meanwhile. METHODS: A total of 68 infants were prospectively recruited for MRI examination under drug sedation (1 week ≤ age ≤ 23 weeks or weight ≤ 5kg). The children were divided into 2 groups according to whether they had preterm birth experience (Preterm group, Atterm group). The Dixon up-and-down method was used to explore ED50. The basic vital signs of the 2 groups were recorded, and the heart rate and SpO2 were recorded every 5 minutes until the infants were discharged from the hospital. The induction time, wake-up time and adverse events were recorded. RESULTS: The ED50 (95%CI) of intranasal dexmedetomidine in the Preterm group and the Atterm group were 2.23 (2.03-2.66) µg/kg and 2.64 (2.49-2.83) µg/kg, respectively (P < .05). the wake-up time was longer in Preterm group (98.00min) than in Atterm group (81.00 min) (P < .05), the incidence of bradycardia in Preterm group was 3/33, which was higher than that in Atterm group (1/35). There was no difference in the induction time between the 2 groups (P > .05), and there was no significant difference in other adverse events. CONCLUSIONS: Intranasal dexmedetomidine can be safely used for sedation in preterm infants undergoing MRI. Compared with term infants, preterm infants have a lower dose of dexmedetomidine, a higher incidence of bradycardia, and a longer weak-up time.

Perioperative analgesic effects of the erector spinae plane block with bupivacaine or bupivacaine-dexmedetomidine in dogs undergoing hemilaminectomy: A randomized controlled trial.

Objective: To compare the perioperative opioid requirements among dogs receiving an erector spinae plane (ESP) block with bupivacaine, with or without dexmedetomidine, and a control group. Animals and procedure: Thirty client-owned, healthy adult dogs undergoing hemilaminectomy were included in this randomized, prospective, blinded clinical study. Dogs were randomly assigned to 1 of 3 treatment groups: Group B, ESP block with bupivacaine; Group BD, ESP block with bupivacaine and dexmedetomidine; and Group C, control. Rescue intra- and postoperative analgesia consisted of fentanyl and methadone, respectively. Postoperative pain was evaluated using the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF). Results: In Group BD, 0/10 dogs required intraoperative fentanyl, compared to 9/10 in Group C (P < 0.001), whereas 1/10 required postoperative methadone, compared to 9/10 in Group B (P = 0.003) and 10/10 in Group C (P < 0.001). The total amount of intraoperative fentanyl (µg/kg) was 0 (0 to 4) in Group B and 0 (0 to 0) in BD, compared to 6 (0 to 8) in C (P = 0.004 and P < 0.001, respectively). Postoperative methadone (mg/kg) required during the first 12 h was 0.5 (0 to 1.4) in Group B (P = 0.003) and 0 (0 to 0) in BD (P < 0.001), compared to C (P = 0.003 and P < 0.001, respectively). Conclusion: An ESP block with bupivacaine, with or without dexmedetomidine, was associated with a reduction in perioperative opioid consumption and provided effective acute pain control.

Effets analgésiques périopératoires du bloc des érecteurs du rachis avec de la bupivacaïne ou de la bupivacaïne-dexmédétomidine chez les chiens subissant une hémilaminectomie: un essai contrôlé randomisé. Objectif: Comparer les besoins périopératoires en opioïdes chez les chiens recevant un bloc des érecteurs de la colonne vertébrale (ESP) avec de la bupivacaïne, avec ou sans dexmédétomidine, et un groupe témoin. Animaux et procédure: Trente chiens adultes en bonne santé appartenant à des clients subissant une hémilaminectomie ont été inclus dans cette étude clinique randomisée, prospective et en aveugle. Les chiens ont été répartis au hasard dans 1 des 3 groupes de traitement: groupe B, bloc ESP avec bupivacaïne; groupe BD, bloc ESP avec bupivacaïne et dexmédétomidine; et groupe C, témoin. L'analgésie de secours peropératoire et postopératoire consistait respectivement en fentanyl et en méthadone. La douleur postopératoire a été évaluée à l'aide du formulaire abrégé de l'échelle de mesure de la douleur de Glasgow (CMPS-SF). Résultats: Dans le groupe BD, 0/10 chiens ont eu besoin de fentanyl peropératoire, contre 9/10 dans le groupe C (P < 0,001), tandis que 1/10 ont eu besoin de méthadone postopératoire, contre 9/10 dans le groupe B (P = 0,003) et 10/10 dans le groupe C (P < 0,001). La quantité totale de fentanyl peropératoire (µg/kg) était de 0 (0 à 4) dans le groupe B et de 0 (0 à 0) dans le groupe BD, contre 6 (0 à 8) dans le groupe C (P = 0,004 et P < 0,001, respectivement). La méthadone postopératoire (mg/kg) nécessaire au cours des 12 premières heures était de 0,5 (0 à 1,4) dans le groupe B (P = 0,003) et de 0 (0 à 0) dans le groupe BD (P < 0,001), par rapport au groupe C (P = 0,003). et P < 0,001, respectivement). Conclusion: Un bloc ESP avec de la bupivacaïne, avec ou sans dexmédétomidine, a été associé à une réduction de la consommation peropératoire d'opioïdes et a permis un contrôle efficace de la douleur aiguë.(Traduit par Dr Serge Messier).

Nicardipine constant rate infusion alleviates the cardiovascular effects of dexmedetomidine infusions without affecting the minimal alveolar concentration in sevoflurane-anesthetized dogs.

Two randomized crossover trials evaluated the effects of nicardipine constant rate infusion (CRI) on 1) the anesthetic potency of sevoflurane and 2) the ability to attenuate dexmedetomidine-induced cardiovascular depression in anesthetized dogs. First, six healthy Beagle dogs weighing 11.7 ± 0.9 kg were allocated to one of three treatments that administered a CRI of carrier (saline) or dexmedetomidine 0.5 or 3.0 µg/kg/h following a loading dose. The minimum alveolar concentration (MAC) of sevoflurane was determined utilizing electric stimuli before and after the loading dose of nicardipine (20 µg/kg intravenously for 10 min), followed by CRI at 40 µg/kg/h with 60 min of equilibration. Subsequently, cardiovascular and blood gas variables were evaluated in another trial under sevoflurane anesthesia at the individual 1.5 MAC. After baseline measurements, the dogs were assigned to two treatments (dexmedetomidine CRI at 0.5 or 3.0 µg/kg/h following a loading dose) with sevoflurane doses adjusted to 1.5 times of MAC equivalent, and the measurements were repeated every 15 min for 120 min. After 60 min, nicardipine CRI at 40 µg/kg/h with a loading dose was added to the dexmedetomidine CRI. Dexmedetomidine infusions significantly decreased the sevoflurane MAC but nicardipine did not significantly alter the MAC either with or without dexmedetomidine CRI in dogs. Dexmedetomidine dose-dependently decreased the cardiac index and increased the systemic vascular resistance index; these effects were fully counteracted by concomitant nicardipine CRI. Nicardipine CRI can be useful for controlling the cardiovascular depression elicited by dexmedetomidine in anesthetized dogs without affecting the anesthetic potency of sevoflurane.

Real-time ultrasound-guided sacral plexus block combined with mild sedation for hemorrhoidectomy and hemorrhoidal artery ligation in a patient with amyotrophic lateral sclerosis: a case report.

BACKGROUND: Patients with amyotrophic lateral sclerosis present perioperative challenges for clinical anesthesiologists for anesthesia-associated complications. CASE PRESENTATION: A 54-year-old Han woman with a 2-year history of amyotrophic lateral sclerosis was scheduled for hemorrhoidectomy and hemorrhoidal artery ligation. We performed real-time ultrasound-guided sacral plexus block with dexmedetomidine under standard monitoring. The anesthesia method met the surgical demands and avoided respiratory complications during the procedures. There was no neurological deterioration after the surgery and 3 months after, the patient was discharged. CONCLUSIONS: Real-time ultrasound-guided sacral plexus block combined with mild sedation may be an effective and safe technique in patients with amyotrophic lateral sclerosis undergoing hemorrhoidectomy and hemorrhoidal artery ligation.

Dexmedetomidine Pretreatment Confers Myocardial Protection and Reduces Mechanical Ventilation Duration for Patients Undergoing Cardiac Valve Replacement under Cardiopulmonary Bypass.

PURPOSE: The study aims to assess the effects of dexmedetomidine (Dex) pretreatment on patients during cardiac valve replacement under cardiopulmonary bypass. METHODS: For patients in the Dex group (n = 52), 0.5 µg/kg Dex was given before anesthesia induction, followed by 0.5 µg/kg/h pumping injection before aortic occlusion. For patients in the control group (n = 52), 0.125 ml/kg normal saline was given instead of Dex. RESULTS: The patients in the Dex group had longer time to first dose of rescue propofol than the control group (P = 0.003). The Dex group required less total dosage of propofol than the control group (P = 0.0001). The levels of cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) were lower in the Dex group than the control group at T4, 8 h after the operation (T5), and 24 h after the operation (T6) (P <0.01). The Dex group required less time for mechanical ventilation than the control group (P = 0.003). CONCLUSION: The study suggests that 0.50 µg/kg Dex pretreatment could reduce propofol use and the duration of mechanical ventilation, and confer myocardial protection without increased adverse events during cardiac valve replacement.

Dexamethasone versus Dexmedetomidine as Adjuvants in Ultrasound Popliteal Sciatic Nerve Block for Hallux Valgus Surgery: A Mono-Centric Retrospective Comparative Study.

Background and Aim: Ultrasound popliteal sciatic nerve block (UPSNB) is commonly performed in foot and ankle surgery. This study aims to assess the use of dexmedetomidine and dexamethasone as adjuvants in UPSNB for hallux valgus (HV) surgery, comparing their efficacy in producing motor and sensory block and controlling postoperative pain. The adverse event rate was also evaluated. Methods: This mono-centric retrospective study included 62 adult patients undergoing HV surgery: 30 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg and dexamethasone 4 mg (Group 1), whereas 32 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg, and dexmedetomidine 1 mcg/Kg (Group 2). At first, the visual analogue scale (VAS) was evaluated after 48 hours. The other outcomes were time to motor block regression, evaluation of the first analgesic drug intake, analgesic effect, adverse effects (hemodynamic disorders, postoperative nausea and vomiting (PONV)) and patient satisfaction. The continuous data were analyzed with student's t-test and the continuous one with χ2. Statistical significance was set at a p-value lower than 0.05. Results: No significant difference was found in VAS after 48 hours (4.5 ± 1.6 vs 4.7 ± 1.7, p = 0.621) to motor block regression (18.9 ± 6.0 vs 18.7 ± 6, p = 0.922). The number of patients that took their first analgesic drug in the first 48 h (p = 0.947 at 6 hours; p = 0.421 at 12 hours; p = 0.122 at 24 hours and p = 0.333 at 48 hours) were not significant. A low and similar incidence of intraoperative hemodynamic disorders was recorded in both groups (hypotension p = 0.593; bradycardia p = 0.881). Neither PONV nor other complication was found. Patients in Group 1 reported a lower degree of interference with sleep (p = 0.001), less interference with daily activities (P = 0.002) and with the affective sphere (P = 0.015) along with a more satisfactory postoperative pain management (p < 0.001) as compared to Group 2. Conclusion: No significant differences were observed in the duration of motor and sensory blockade between patients in both groups. Additionally, both groups showed good pain control with a low rate of adverse effects, even if there was no clinical difference between the groups. However, patients who received dexamethasone reported experiencing less interference with their sleep, daily activities and overall emotional well-being, and overall pain control.

Comparative evaluation of nebulized versus intravenous dexmedetomidine on intubating conditions during awake fiberoptic nasotracheal intubation.

BACKGROUND: There is a search for an ideal agent to facilitate awake fiberoptic intubation (AFOI). Dexmedetomidine is a selective α2 agonist which can be administered through intravenous, intramuscular, buccal, intranasal & inhalational routes. It provides good intubation conditions without oxygen desaturation but may cause hypotension and bradycardia when administered intravenously. Hence, alternative routes of administering dexmedetomidine which may improve its safety profile are worth exploring. METHODS: In this randomised, controlled, double-blind trial, 46 ASA I/II adult participants scheduled for elective ENT surgery were randomly allocated to Group ND (Nebulised Dexmedetomidine) (n = 23) to receive nebulisation with dexmedetomidine 1µg.kg-1 and Group ID (Intravenous Dexmedetomidine) (n = 23) to receive intravenous dexmedetomidine 1µg.kg-1 before AFOI. All the patients received injection midazolam 1 mg i.v. as premedication before anaesthesia was initiated. The primary outcome was the cough score. The secondary outcomes were the RSS, SAYGO boluses, post-intubation score, hemodynamic parameters, recall of the procedure, patient satisfaction score and any side effects. RESULTS: The cough score was significantly lower in nebulized group (2.43 ± 0.992 vs 3.52 ± 1.082) with p = 0.001. RSS(3.30 ± 0.926 vs 4.22 ± 1.126; p = 0.004), number of SAYGO boluses required (2.74 ± 0.864 vs 3.57 ± 1.161; p = 0.009) & the post intubation score (1.48 ± 0.593 vs 2.17 ± 0.778; p = 0.001) were also significantly lower in nebulized group. CONCLUSIONS: Nebulisation with dexmedetomidine results in desirable degree of sedation and better tolerance of the procedure with adequate attenuation of the haemodynamic responses to intubation.

Effects of tasipimidine premedication with and without methadone and dexmedetomidine on cardiovascular variables during propofol-isoflurane anaesthesia in Beagle dogs.

OBJECTIVE: To evaluate cardiovascular effects of oral tasipimidine on propofol-isoflurane anaesthesia with or without methadone and dexmedetomidine at equianaesthetic levels. STUDY DESIGN: Prospective, placebo-controlled, blinded, experimental trial. ANIMALS: A group of seven adult Beagle dogs weighing (mean ± standard deviation) 12.4 ± 2.6 kg and a mean age of 20.6 ± 1 months. METHODS: The dogs underwent four treatments 60 minutes before induction of anaesthesia with propofol. PP: placebo orally and placebo (NaCl 0.9%) intravenously (IV); TP: tasipimidine 30 µg kg-1 orally and placebo IV; TMP: tasipimidine 30 µg kg-1 orally and methadone 0.2 mg kg-1 IV; and TMPD: tasipimidine 30 µg kg-1 orally with methadone 0.2 mg kg-1 and dexmedetomidine 1 µg kg-1 IV followed by 1 µg kg-1 hour-1. Isoflurane in oxygen was maintained for 120 minutes at 1.2 individual minimum alveolar concentration preventing motor movement. Cardiac output (CO), tissue blood flow (tbf), tissue oxygen saturation (stO2) and relative haemoglobin content were determined. Arterial and mixed venous blood gases, arterial and pulmonary artery pressures and heart rate (HR) were measured at baseline; 60 minutes after oral premedication; 5 minutes after IV premedication; 15, 30, 60, 90 and 120 minutes after propofol injection; and 30 minutes after switching the vaporiser off. Data were analysed by two-way anova for repeated measures; p < 0.05. RESULTS: Tasipimidine induced a significant 20-30% reduction in HR and CO with decreases in MAP (10-15%), tbf (40%) and stO2 (43%). Blood pressure and oxygenation variables were mainly influenced by propofol-isoflurane-oxygen anaesthesia, preceded by short-lived alterations related to IV methadone and dexmedetomidine. CONCLUSIONS AND CLINICAL RELEVANCE: Tasipimidine induced mild to moderate cardiovascular depression. It can be incorporated into a common anaesthetic protocol without detrimental effects in healthy dogs, when anaesthetics are administered to effect and cardiorespiratory function is monitored.

Clinical usefulness of nebulized dexmedetomidine for conscious sedation in daycare flexible bronchoscopy in Southern India.

BACKGROUND: Sedative agents used in bronchoscopy require trained personnel to administer and monitor the patient. This increases the procedure cost, duration, and inpatient stay. Inhalational administration of sedative agents can be a practical solution to the issue. Dexmedetomidine in the inhalational form could give results similar to the intravenous form without significant adverse events. MATERIALS AND METHODS: The study is prospective, randomized, and double-blinded study. Patients needing bronchoscopy were randomized to receive the nebulized form of either dexmedetomidine or saline (0.9%) before bronchoscopy. The study parameters are assessed and recorded before, during, and after bronchoscopy. Data collected are analyzed using the SPSS software. DISCUSSION: The side effects limit using commonly administered sedation agents in bronchoscopy, such as midazolam, fentanyl, and dexmedetomidine. The nebulized dexmedetomidine is safe with proven efficacy when compared to the placebo. Proceduralist-administered conscious sedation reduces the overall cost and shortens inpatient stays. Attenuation of hemodynamic parameters by dexmedetomidine could be an advantage for the physician in reducing an untoward cardiac event. CONCLUSION: Dexmedetomidine in the nebulized form improves the comfort of patients during the procedure. It blunts the pressure response during bronchoscopy and could be a safer and cost-effective agent in its nebulized form for conscious sedation in bronchoscopy. The study is approved by the institutional ethics committee (IEC KMC MLR 10-2021-310).

The effect of dexmedetomidine on the postoperative recovery of patients with severe traumatic brain injury undergoing craniotomy treatment: a retrospective study.

BACKGROUND: Traumatic brain injury (TBI) has been a worldwide problem for neurosurgeons. Patients with severe TBI may undergo craniotomy. These patients often require sedation after craniotomy. Dexmedetomidine (DEX) has been used in patients receiving anesthesia and in intensive care units. Not much is known about the postoperative effect of DEX in patients with severe TBIs undergoing craniotomy. The purpose of this study was to explore the effects of postoperative DEX administration on severe TBI patients who underwent craniotomy. METHODS: Patients who underwent craniectomy for severe TBI at our hospital between January 2019 and February 2022 were included in this study. The patients were admitted to the intensive care unit (ICU) after surgery to receive sedative medication. The patients were then divided into DEX and control groups. We analyzed the sedation, hemodynamics, and other conditions of the patients (hypoxemia, duration of ventilation during endotracheal intubation, whether tracheotomy was performed, and the duration in the ICU) during their ICU stay. Other conditions, such as delirium after the patients were transferred to the general ward, were also analyzed. RESULTS: A total of 122 patients were included in this study. Among them, 53 patients received DEX, and the remaining 69 did not. The incidence of delirium in the general ward in the DEX group was significantly lower than that in the control group (P < 0.05). The incidence of bradycardia in the control group was significantly lower than that in the DEX group (P < 0.05). Other data from the DEX group and the control group (hypotension, hypoxemia, etc.) were not significantly different (P > 0.05). CONCLUSION: The use of DEX in the ICU can effectively reduce the incidence of delirium in patients who return to the general ward after craniotomy. DEX had no adverse effect on the prognosis of patients other than causing bradycardia.

Combined Dexamethasone and Dexmedetomidine as Adjuncts to Popliteal and Saphenous Nerve Blocks in Patients Undergoing Surgery of the Foot or Ankle: A Randomized, Blinded, Placebo-controlled Clinical Trial.

BACKGROUND: Both dexamethasone and dexmedetomidine increase the duration of analgesia of peripheral nerve blocks. The authors hypothesized that combined intravenous dexamethasone and intravenous dexmedetomidine would result in a greater duration of analgesia when compared with intravenous dexamethasone alone and placebo. METHODS: The authors randomly allocated participants undergoing surgery of the foot or ankle under general anesthesia and with a combined popliteal (sciatic) and saphenous nerve block to a combination of 12 mg dexamethasone and 1 µg/kg dexmedetomidine, 12 mg dexamethasone, or placebo (saline). The primary outcome was the duration of analgesia measured as the time from block performance until the first sensation of pain in the surgical area as reported by the participant. The authors predefined a 33% difference in the duration of analgesia as clinically relevant. RESULTS: A total of 120 participants from two centers were randomized and 119 analyzed for the primary outcome. The median [interquartile range] duration of analgesia was 1,572 min [1,259 to 1,715] with combined dexamethasone and dexmedetomidine, 1,400 min [1,133 to 1,750] with dexamethasone alone, and 870 min [748 to 1,138] with placebo. Compared with placebo, the duration was greater with combined dexamethasone and dexmedetomidine (difference, 564 min; 98.33% CI, 301 to 794; P < 0.001) and with dexamethasone (difference, 489 min; 98.33% CI, 265 to 706; P < 0.001). The prolongations exceeded the authors' predefined clinically relevant difference. The duration was similar when combined dexamethasone and dexmedetomidine was compared with dexamethasone alone (difference, 61 min; 98.33% CI, -222 to 331; P = 0.614). CONCLUSIONS: Dexamethasone with or without dexmedetomidine increased the duration of analgesia in patients undergoing surgery of the foot or ankle with a popliteal (sciatic) and saphenous nerve block. Combined dexamethasone and dexmedetomidine did not increase the duration of analgesia when compared with dexamethasone.

A comparative analysis of opioid-free and opioid-sparing anaesthesia techniques for laparoscopic ovariectomy in healthy dogs.

OBJECTIVE: To compare the perioperative analgesic effects of an opioid-free (OFA) and an opioid-sparing (OSA) anaesthetic protocol in dogs undergoing laparoscopic ovariectomy. STUDY DESIGN: Prospective, randomized, blinded, clinical trial. ANIMALS: A group of 28 client-owned dogs. METHODS: Dogs were allocated to one of two groups. The OFA group was administered intramuscular (IM) dexmedetomidine 5 µg kg-1 and ketamine 1 mg kg-1, followed by two intraoperative constant rate infusions (CRIs) of dexmedetomidine (3 µg kg-1 hour-1) and lidocaine (1 mg kg-1 loading dose, 2 mg kg-1 hour-1). The OSA group was administered IM dexmedetomidine 5 µg kg-1, ketamine 1 mg kg-1 and methadone 0.2 mg kg-1, followed by two intraoperative saline CRIs. In both groups, anaesthesia was induced with intravenous (IV) propofol 2 mg kg-1 and diazepam 0.2 mg kg-1 and maintained with isoflurane. Rescue dexmedetomidine (0.5 µg kg-1) was administered IV if there was a 20% increase in cardiovascular variables compared with pre-stimulation values. Ketorolac (0.5 mg kg-1) was administered IV when the surgery ended. Postoperative analgesia was evaluated using the Short Form-Glasgow Composite Measure Pain Scale and methadone (0.2 mg kg-1) was administered IM if the pain score was ≥ 6/24. Statistical analysis included mixed analysis of variance, Chi-square test and Mann-Whitney U test. RESULTS: There were no significant differences in the intraoperative monitored variables between groups. The OFA group showed a significantly lower intraoperative rescue analgesia requirement (p = 0.016) and lower postoperative pain scores at 3 (p =0.001) and 6 (p < 0.001) hours. No dogs were administered rescue methadone postoperatively. CONCLUSIONS AND CLINICAL RELEVANCE: Although both groups achieved acceptable postoperative pain scores with no need for further intervention, the analgesic efficacy of the OFA protocol was significantly superior to that of the OSA protocol presented and was associated with a lower intraoperative rescue analgesia requirement and early postoperative pain scores.

Anaesthetic-sparing effect of the anxiolytic drug tasipimidine in Beagle dogs.

OBJECTIVE: To evaluate the effect of oral tasipimidine on dog handling, ease of catheter placement and propofol and isoflurane requirements for anaesthesia. STUDY DESIGN: Placebo-controlled, randomized, blinded, experimental trial. ANIMALS: A group of seven adult Beagle dogs weighing (mean ± standard deviation) 13.1 ± 2.7 kg with a mean age of 18.6 ± 1 months. METHODS: The dogs underwent four treatments before induction of anaesthesia with propofol. PP: placebo orally (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) intravenously (IV). TP: tasipimidine 30 µg kg-1 (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) IV. TMP: tasipimidine 30 µg kg-1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg-1 IV. TMPD: tasipimidine 30 µg kg-1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg-1 and dexmedetomidine 1 µg kg-1 IV followed by a dexmedetomidine constant rate infusion of 1 µg kg-1 hour-1. Sedation, response to catheter placement, intubation quality, time to loss of consciousness, time to intubation, required dose of propofol and minimum alveolar isoflurane concentration preventing motor movement (MACNM) were determined. A mixed-model analysis or the Friedman and Mann-Whitney test were used; p-value < 0.05. RESULTS: Response to catheter placement did not differ between treatments. Tasipimidine alone reduced the propofol dose by 30%. Addition of methadone or methadone and dexmedetomidine reduced the propofol dose by 48% and 50%, respectively. Isoflurane MACNM was reduced by 19% in tasipimidine-medicated dogs, whereas in combination with methadone or methadone and dexmedetomidine, isoflurane MACNM was reduced by 35%. CONCLUSIONS AND CLINICAL RELEVANCE: An anxiolytic dose of tasipimidine induced mild signs of sedation in dogs and reduced propofol and isoflurane requirements to induce and maintain anaesthesia, which needs to be considered in an anaesthetic plan.

The Effect of Dexmedetomidine as a Local Anesthetic Adjuvant for Iliac Fascia Compartment Block on Postoperative Delirium in Elderly Patients Undergoing Elective Hip Surgery.

INTRODUCTION: We analyzed the effect of dexmedetomidine (DEX) as a local anesthetic adjuvant on postoperative delirium (POD) in elderly patients undergoing elective hip surgery. METHODS: In this study, 120 patients undergoing hip surgery were enrolled and randomly assigned to two groups: fascia iliaca compartment block with DEX + ropivacaine (the Y group, n = 60) and fascia iliaca compartment block with ropivacaine (the R group, n = 60). The primary outcomes: presence of delirium during the postanesthesia care unit (PACU) period and on the first day (D1), the second day (D2), and the third day (D3) after surgery. The secondary outcomes: preoperative and postoperative C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), occurrence of insomnia on the preoperative day, day of operation, D1 and D2; HR values of patients in both groups before iliac fascia block (T1), 30 min after iliac fascia block (T2), at surgical incision (T3), 20 min after incision (T4), when they were transferred out of the operating room (T5) and after leaving the recovery room (T6) at each time point; VAS for T1, PACU, D1, D2; the number of patients requiring remedial analgesics within 24 h after blockade and related complications between the two groups. RESULTS: A total of 97 patients were included in the final analysis, with 11 and 12 patients withdrawing from the R and Y groups, respectively. The overall incidence of POD and its incidence in the PACU and ward were all lesser in the Y group than in the R group (p < 0.05). Additionally, fewer cases required remedial analgesia during the PACU period, and more vasoactive drugs were used for maintaining circulatory system stability in the Y group as compared to the R group (p < 0.05). At the same time, the incidence of intraoperative and postoperative bradycardia in the Y group was higher than that in the R group, accompanied by lower postoperative CRP and ESR (all p < 0.05). CONCLUSION: Ultrasound-guided high fascia iliaca compartment block with a combination of ropivacaine and DEX can reduce the incidence of POD, the use of intraoperative opioids and postoperative remedial analgesics, and postoperative inflammation in elderly patients who have undergone hip surgery, indicating that this method could be beneficial in the prevention and treatment of POD.

Effects of Midazolam/Dexmedetomidine with Buprenorphine or Extended-release Buprenorphine Anesthesia in C57BL/6 Mice.

The effects of commonly used injectable combinations of anesthetics such as ketamine and xylazine, with or without acepromazine, vary widely across individuals, have a shallow-dose response curve, and do not provide long-term analgesia. These drawbacks indicate the importance of continuing efforts to develop safe and effective injectable anesthetic combinations for mice. In this study, a series of experiments was designed to validate the use of dexmedetomidine and midazolam to provide chemical restraint for nonpainful procedures and the addition of buprenorphine or extended-release buprenorphine to reliably provide a surgical plane of anesthesia in C57BL/6J mice. Loss of consciousness was defined as the loss of the righting reflex (LORR); a surgical plane of anesthesia was defined as the LORR and loss of pedal withdrawal after application of a 300 g noxious stimulus to a hind paw. The combination of intraperitoneal 0.25 mg/kg dexmedetomidine and 6 mg/kg midazolam produced LORR, sufficient for nonpainful or noninvasive procedures, without achieving a surgical plane in 19 of 20 mice tested. With the addition of subcutaneous 0.1 mg/kg buprenorphine or 1 mg/kg buprenorphine-ER, 29 of 30 mice achieved a surgical plane of anesthesia. The safety and efficacy of the regimen was then tested by successfully performing a laparotomy in 6 mice. No deaths occurred in any trial, and, when administered 1 mg/kg atipamezole IP, all mice recovered their righting reflex within 11 min. The anesthetic regimen developed in this study is safe, is reversible, and includes analgesics that previous studies have shown provide analgesia beyond the immediate postsurgical period. Buprenorphine-ER can be safely substituted for buprenorphine for longer-lasting analgesia.

The effects of selected sedatives on basal and stimulated serum cortisol concentrations in healthy dogs.

Background: Hormone assessment is typically recommended for awake, unsedated dogs. However, one of the most commonly asked questions from veterinary practitioners to the endocrinology laboratory is how sedation impacts cortisol concentrations and the adrenocorticotropic hormone (ACTH) stimulation test. Butorphanol, dexmedetomidine, and trazodone are common sedatives for dogs, but their impact on the hypothalamic-pituitary-adrenal axis (HPA) is unknown. The objective of this study was to evaluate the effects of butorphanol, dexmedetomidine, and trazodone on serum cortisol concentrations. Methods: Twelve healthy beagles were included in a prospective, randomized, four-period crossover design study with a 7-day washout. ACTH stimulation test results were determined after saline (0.5 mL IV), butorphanol (0.3 mg/kg IV), dexmedetomidine (4 µg/kg IV), and trazodone (3-5 mg/kg PO) administration. Results: Compared to saline, butorphanol increased basal (median 11.75 µg/dL (range 2.50-23.00) (324.13 nmol/L; range 68.97-634.48) vs 1.27 µg/dL (0.74-2.10) (35.03 nmol/L; 20.41-57.93); P < 0.0001) and post-ACTH cortisol concentrations (17.05 µg/dL (12.40-26.00) (470.34 nmol/L; 342.07-717.24) vs 13.75 µg/dL (10.00-18.90) (379.31 nmol/L; 275.96-521.38); P ≤ 0.0001). Dexmedetomidine and trazodone did not significantly affect basal (1.55 µg/dL (range 0.75-1.55) (42.76 nmol/L; 20.69-42.76); P = 0.33 and 0.79 µg/dL (range 0.69-1.89) (21.79 nmol/L; 19.03-52.14); P = 0.13, respectively, vs saline 1.27 (0.74-2.10) (35.03 nmol/L; 20.41-57.93)) or post-ACTH cortisol concentrations (14.35 µg/dL (range 10.70-18.00) (395.86 nmol/L; 295.17-496.55); (P = 0.98 and 12.90 µg/dL (range 8.94-17.40) (355.86 nmol/L; 246.62-480); P = 0.65), respectively, vs saline 13.75 µg/dL (10.00-18.60) (379.31 nmol/L; 275.86-513.10). Conclusion: Butorphanol administration should be avoided prior to ACTH stimulation testing in dogs. Further evaluation of dexmedetomidine and trazodone's effects on adrenocortical hormone testing in dogs suspected of HPA derangements is warranted to confirm they do not impact clinical diagnosis.