The antinociceptive effects of intravenous administration of three doses of butorphanol tartrate or naloxone hydrochloride following hydromorphone hydrochloride to healthy conscious cats.

OBJECTIVE: To evaluate thermal antinociception from intravenous (IV) administration of hydromorphone alone or followed by butorphanol or naloxone in cats. STUDY DESIGN: Randomized, controlled, masked, crossover design. ANIMALS: A group of eight adult female cats. METHODS: Cats were administered six treatments of two IV injections 30 minutes apart: treatments S-S, two 0.9% saline; H-S, hydromorphone (0.1 mg kg-1) and saline; H-LB, hydromorphone and butorphanol (0.02 mg kg-1); H-MB, hydromorphone and butorphanol (0.1 mg kg-1); H-HB, hydromorphone and butorphanol (0.2 mg kg-1); H-N, hydromorphone and naloxone (0.04 mg kg-1). Skin temperature (ST), thermal threshold (TT) and sedation score (SS) were recorded before (baseline) and for 8 hours after the first injection. Percentage maximum possible effect (%MPE), thermal excursion (TE), TT, SS and ST were compared using two-way repeated measures anova or Friedman test followed by Tukey's or Dunn's multiple comparisons test when appropriate. Significance was set at p ≤ 0.05. RESULTS: Data from seven cats were analyzed. There were no significant differences among treatments in baseline values, SS and within S-S over time. Compared with respective 0.5 hour values following hydromorphone administration, %MPE was significantly lower at 4-8 hours for H-S; at 3-8 hours for H-LB; at 4-8 hours for H-MB; at 6-8 hours for H-HB and at 1-8 hours for H-N. Compared with respective 0.5 hour values, TE was significantly lower at 4-8 hours for H-S; at 3-8 hours for H-LB; at 2 and 4-8 hours for H-MB; at 6 and 8 hours for H-HB and at 1-8 hours for H-N. CONCLUSIONS AND CLINICAL RELEVANCE: Butorphanol and naloxone reduced hydromorphone-induced thermal antinociception. Butorphanol preserved hydromorphone antinociceptive properties better than naloxone. Butorphanol is recommended during non-life-threatening scenarios as a partial reversal agent for hydromorphone in cats.

Anesthetic management and anesthesia-related complications in dogs with a dilated cardiomyopathy phenotype: a retrospective study of 30 dogs (2010-2024).

OBJECTIVE: To describe perioperative anesthetic management in canines with a dilated cardiomyopathy (DCM) phenotype and to compare the frequency of general anesthesia-related complications with a control group of dogs without heart disease. ANIMALS: 30 dogs with DCM phenotype (cases) and 30 dogs without heart disease (controls). METHODS: Dogs presented to a teaching hospital between 2010 and 2024 that were diagnosed with a DCM phenotype via echocardiography were included in this study. Controls were dogs that presented during the same time period and were matched with cases based on their age, breed, and type of procedure; however, no standardization of treatment between the groups was performed. Medical records were reviewed to evaluate the occurrence of anesthetic complications. RESULTS: Of dogs with a DCM phenotype, 2 had overt DCM, 22 had occult DCM, and 6 had equivocal DCM. Dogs with DCM exhibited a lower likelihood of being premedicated with dexmedetomidine or induced with propofol. Conversely, DCM dogs were more likely to be induced with etomidate or midazolam compared to their counterparts without DCM. Dogs with DCM demonstrated an increased likelihood of experiencing cardiac arrhythmias during anesthesia, received comparatively lower volumes of IV fluids, and were more likely to be administered dobutamine during anesthesia. No significant differences were identified in terms of postanesthesia complications or survival rates to discharge. CLINICAL RELEVANCE: Dogs with a DCM phenotype, primarily characterized by asymptomatic presentation, demonstrated comparable perioperative outcomes under general anesthesia when compared to matched controls, though the lack of standardization in anesthetic management limits definitive conclusions.

The Effects of Prophylactic Dexmedetomidine Administration on General Anesthesia Recovery Quality in Healthy Dogs Anesthetized With Sevoflurane and a Fentanyl Constant Rate Infusion Undergoing Elective Orthopedic Procedures.

To determine the effects of a dexmedetomidine slow bolus, administered prior to extubation, on recovery from sevoflurane-anesthesia and a fentanyl continuous rate infusion (CRI) in dogs undergoing orthopedic surgical procedures. Sixty-two client-owned, healthy dogs weighing 27.4 ± 11 kg undergoing elective orthopedic procedures were premedicated with: 0.1 mg/kg hydromorphone intramuscular, 0.05 mg/kg hydromorphone intravenously (IV) or 5 mcg/kg fentanyl IV. Following premedication, dogs were induced with propofol, administered locoregional anesthesia and maintained with sevoflurane and a fentanyl CRI (5-10 mcg/kg/hr). Dogs were randomly assigned to one of two treatment groups: 0.5 mcg/kg dexmedetomidine (DEX) or 0.5 ml/kg saline (SAL). Following surgery, patients were discontinued from the fentanyl CRI and administered DEX or SAL IV over 10 min. Following treatment, dogs were discontinued from sevoflurane and allowed to recover without interference. Recoveries were video recorded for 5 min following extubation and assessed by two blinded anesthesiologists using a visual analog scale (VAS; 0-10 cm) and a numerical rating scale (NRS; 1-10). Mean arterial pressure (MAP), heart rate (HR), pulse oximetry (SpO2), temperature, respiratory rate (RR), and end-tidal sevoflurane (EtSevo) and carbon dioxide (EtCO2) concentrations were recorded at specific time-points from induction to 5 min post-bolus administration and analyzed using linear mixed models. Fentanyl, propofol, and hydromorphone dose and the time to extubation were compared using an unpaired t-test. Differences in recovery scores between groups were evaluated with a Mann-Whitney test. Data reported as mean ± SD or median [interquartile range] when appropriate. A p < 0.05 was significant. There were no significant differences between groups in fentanyl, propofol, and hydromorphone dose, duration of anesthesia, intraoperative MAP, HR, RR, SpO2, temperature, EtCO2, EtSevo or anesthetic protocol. MAP was higher in DEX compared to SAL at 10 (104 ± 27 and 83 ± 23, respectively) and 15 (108 ± 28 and 86 ± 22, respectively) min after treatment. DEX had significantly lower VAS [0.88 (1.13)] and NRS [2.0 (1.5)] scores when compared to SAL [VAS = 1.56 (2.59); NRS = 2.5 (3.5)]. Time to extubation (min) was longer for DEX (19.7 ± 11) when compared to SAL (13.4 ± 10). Prophylactic dexmedetomidine improves recovery quality during the extubation period, but prolongs its duration, in sevoflurane-anesthetized healthy dogs administered fentanyl.

Clinical Heinz Body Anemia in a Cat After Repeat Propofol Administration Case Report.

Heinz body formation has been reported in cats repeatedly administered propofol for anesthesia induction, although the resultant changes were deemed of little clinical significance (1, 2). This report suggests repeated propofol administration to some individual cats might induce anemia with clinical signs and cessation of propofol administration may result in rapid resolution. A 9-years-old American Domestic Shorthair cat receiving a 20-fraction radiation protocol for lateral thoracic fibrosarcoma showed lethargy, decreased appetite and activity, and Heinz body (3+ on blood smear examination) anemia (packed cell volume 22%; reference interval 24-45%) after 12 repeated propofol anesthesia inductions. The anesthesia induction protocol was adjusted to exclude propofol. Over the following week, the anemia resolved (packed cell volume, 30%), and the cat's activity level, appetite and attitude improved. The total dose of propofol received over the 12 treatments was 62.4 mg/kg.

Transient Activation of the Hedgehog-Gli Pathway Rescues Radiotherapy-Induced Dry Mouth via Recovering Salivary Gland Resident Macrophages.

Irreversible hypofunction of salivary glands is a common side effect of radiotherapy for head and neck cancer and is difficult to remedy. Recent studies indicate that transient activation of Hedgehog signaling rescues irradiation-impaired salivary function in animal models, but the underlying mechanisms are largely unclear. Here, we show in mice that activation of canonical Gli-dependent Hedgehog signaling by Gli1 gene transfer is sufficient to recover salivary function impaired by irradiation. Salivary gland cells responsive to Hedgehog/Gli signaling comprised small subsets of macrophages, epithelial cells, and endothelial cells, and their progeny remained relatively rare long after irradiation and transient Hedgehog activation. Quantities and activities of salivary gland resident macrophages were substantially and rapidly impaired by irradiation and restored by Hedgehog activation. Conversely, depletion of salivary gland macrophages by clodronate liposomes compromised the restoration of irradiation-impaired salivary function by transient Hedgehog activation. Single-cell RNA sequencing and qRT-PCR of sorted cells indicated that Hedgehog activation greatly enhances paracrine interactions between salivary gland resident macrophages, epithelial progenitors, and endothelial cells through Csf1, Hgf, and C1q signaling pathways. Consistently, expression of these paracrine factors and their receptors in salivary glands decreased following irradiation but were restored by transient Hedgehog activation. These findings reveal that resident macrophages and their prorepair paracrine factors are essential for the rescue of irradiation-impaired salivary function by transient Hedgehog activation and are promising therapeutic targets of radiotherapy-induced irreversible dry mouth. SIGNIFICANCE: These findings illuminate a novel direction for developing effective treatment of irreversible dry mouth, which is common after radiotherapy for head and neck cancer and for which no effective treatments are available. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/24/5531/F1.large.jpg.See related commentary by Coppes, p. 5462.

Anesthesia and analgesia for geriatric veterinary patients.

The number of geriatric veterinary patients presented for anesthesia appears to be increasing. This article summarizes physiologic changes that occur in geriatric patients that are relevant to anesthesia. Proper patient preparation and vigilant monitoring are the best defense against anesthetic problems in the geriatric animal. The authors also discuss particular anesthetic problems as they relate to geriatric patients and seek to present solutions to these problems.