Development and comparison of an esophageal Doppler monitoring-based treatment algorithm with a heart rate and blood pressure-based treatment algorithm for goal-directed fluid therapy in anesthetized dogs: A pilot study

The objective of this pilot study was to determine the feasibility of a study comparing the efficacy of an esophageal Doppler monitor (EDM)-based fluid therapy algorithm with a heart rate (HR)- and mean arterial blood pressure (MAP)-based algorithm in reducing hypotension and fluid load in anesthetized dogs. Client-owned dogs undergoing general anesthesia for surgical procedures were randomized to two groups. An EDM probe for monitoring blood flow in the descending aorta was placed in each dog before receiving a crystalloid bolus (5 mL/kg) over 5 min. Fluids were repeated in case of fluid responsiveness defined by increasing Velocity Time Integral (VTI) ≥ 10% in group EDM and by decreasing HR ≥ 5 beats/min and/or increasing MAP ≥ 3 mmHg in group standard. The feasibility outcomes included the proportion of dogs completing the study and the clinical applicability of the algorithms. The clinical outcomes were the total administered fluid volume and the duration of hypotension defined as MAP < 60 mmHg. Data was compared between groups with Mann-Whitney U-test. p < 0.05 were deemed significant. Of 25 dogs screened, 14 completed the study (56%). There were no differences in the proportion of recorded time spent in hypotension in group standard [2 (0–39)% (median (range))] and EDM [0 (0–63) %, p = 1], or the total volume of fluids [standard 8 (5–14) mL/kg/h, EDM 11 (4–20) mL/kg/h, p = 0.3]. This study declined the feasibility of a study comparing the impact of two newly developed fluid therapy algorithms on hypotension and fluid load in their current form. Clinical outcome analyses were underpowered and no differences in treatment efficacy between the groups could be determined. The conclusions drawn from this pilot study provide important information for future study designs

Evaluation of the Effect of Induced Endotoxemia on ROTEM S® and Platelet Parameters in Beagle Dogs Anaesthetized with Sevoflurane

Endotoxemia is thought to induce severe changes in coagulation status. In this study, blood samples from six beagle dogs receiving 1 mg/kg E. coli lipopolysaccharide (LPS) intravenously were analyzed to describe the concurrent changes in platelet count, platelet function assessed with impedance thromboaggregometry, thromboelastometry and d-dimers during artificially induced endotoxemia and its therapy with fluids and vasopressors at five timepoints (baseline, after LPS and 30 mL/kg Ringer’s acetate, during noradrenaline ± dexmedetomidine infusion, after a second fluid bolus and a second time after vasopressors). Results were analyzed for changes over time with the Friedman test, and statistical significance was set at p < 0.05. We found decreased platelet count and function and changes in all platelet-associated rotational thromboelastometry (ROTEM) variables indicating hypocoagulability, as well as increases in d-dimers indicating fibrinolysis within one hour of intravenous administration of LPS, with partial recovery of values after treatment and over time. The fast changes in platelet count, platelet function and ROTEM variables reflect the large impact of endotoxemia on the coagulation system and support repeated evaluation during the progress of endotoxemic diseases. The partial recovery of the variables after initiation of fluid and vasopressor therapy may reflect the positive impact of the currently suggested therapeutic interventions during septic shock in dogs

Ketamine administration in idiopathic epileptic and healthy control dogs: Can we detect differences in brain metabolite response with spectroscopy?

IntroductionIn recent years ketamine has increasingly become the focus of multimodal emergency management for epileptic seizures. However, little is known about the effect of ketamine on brain metabolites in epileptic patients. Magnetic resonance spectroscopy (MRS) is a non-invasive technique to estimate brain metabolites in vivo. Our aim was to measure the effect of ketamine on thalamic metabolites in idiopathic epileptic (IE) dogs using 3 Tesla MRS. We hypothesized that ketamine would increase the glutamine—glutamate (GLX)/creatine ratio in epileptic dogs with and without antiseizure drug treatment, but not in control dogs. Furthermore, we hypothesized that no different responses after ketamine administration in other measured brain metabolite ratios between the different groups would be detected.MethodsIn this controlled prospective experimental trial IE dogs with or without antiseizure drug treatment and healthy client-owned relatives of the breeds Border Collie and Greater Swiss Mountain Dog, were included. After sedation with butorphanol, induction with propofol and maintenance with sevoflurane in oxygen and air, a single voxel MRS at the level of the thalamus was performed before and 2 min after intravenous administration of 1 mg/kg ketamine. An automated data processing spectral fitting linear combination model algorithm was used to estimate all commonly measured metabolite ratios. A mixed ANOVA with the independent variables ketamine administration and group allocation was performed for all measured metabolites. A p &lt; 0.05 was considered statistically significant.ResultsTwelve healthy control dogs, 10 untreated IE and 12 treated IE dogs were included. No significant effects for GLX/creatine were found. However, increased glucose/creatine ratios were found (p &lt; 0.001) with no effect of group allocation. Furthermore, increases in the GABA/creatine ratio were found in IEU dogs.DiscussionMRS was able to detect changes in metabolite/creatine ratios after intravenous administration of 1 mg/kg ketamine in dogs and no evidence was found that excitatory effects are induced in the thalamus. Although it is beyond the scope of this study to investigate the antiseizure potential of ketamine in dogs, results of this research suggest that the effect of ketamine on the brain metabolites could be dependent on the concentrations of brain metabolites before administration

Atipamezole Reverses Cardiovascular Changes Induced by High-Dose Medetomidine in Cats Undergoing Sedation for Semen Collection

This study aimed at describing the change in echocardiographic variables after high-dose medetomidine and the reversal with atipamezole in six cats undergoing sedation for semen collection. Further cardiac Troponin I (cTnI) concentration and the effect of repeated sedation were assessed. Echocardiography was performed before and 20 min after sedation with 0.1 mg/kg medetomidine intramuscularly (IM) for urethral catheterisation. Prior to epididymectomy, S-ketamine was administered intravenously. Twenty minutes after reversal with 0.5 mg/kg atipamezole IM, the third echocardiography was performed. Sedation with medetomidine and reversal with atipamezole was repeated on day 7, 14, 21 and 28. Heart rate (HR) and rhythm were monitored throughout all sedations. On day 0 and 28 cTnI concentrations were measured before and after the procedure. After normality testing, the values were compared over time. The administration of medetomidine led to a marked reduction in HR, cardiac output and ventricular systolic function and a significant increase in left ventricular dimensions. Rhythm abnormalities, such as ventricular premature complexes and idioventricular rhythm, could be observed. The administration of atipamezole completely reversed sedation and the changes in haemodynamic variables. No significant increase in cTnI concentrations could be detected, although two out of six cats showed values above the reference range

Evaluation of the Analgesic Efficacy of Undiluted Intraperitoneal and Incisional Ropivacaine for Postoperative Analgesia in Dogs after Major Abdominal Surgery

Recommendations for intraperitoneal (IP) and incisional (INC) administration of local anaesthetics after visceral surgery exist, but evidence is scarce. This prospective, randomized, blinded, controlled, clinical trial compared postoperative pain in dogs undergoing major abdominal surgery. Sixteen client-owned dogs were anaesthetized with a standardized balanced protocol including opioids and received either 2 mg/kg ropivacaine IP (0.27 mL/kg) and a 1 mg/kg INC splash (0.13 mL/kg) or equal volumes of saline. Influence of the treatment on heart rate (HR) and postoperative pain was assessed using the Short Form of the Glasgow Composite Pain Scale (GCPS-SF), a dynamic interactive visual analogue scale (DIVAS) and mechanical nociceptive threshold testing (MNT). Data was tested with mixed ordinal regression and log linear mixed models for 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 h after extubation. Rescue analgesia was given to 3/8 dogs after ropivacaine and 0/8 dogs after saline. GCPS-SF and MNT were not different between groups. DIVAS was slightly higher after ropivacaine (odds increased by 5.44 (confidence interval (CI) 1.17–9.96, p = 0.012)), and HR after ropivacaine was 0.76 * that after saline (CI 0.61–0.96, p = 0.02) with no effect of time (p = 0.1). Undiluted ropivacaine IP and INC was not beneficial for postoperative analgesia

Intraperitoneal and incisional ropivacaine did not improve postoperative analgesia after multimodal anaesthesia compared with saline in dogs undergoing ovariohysterectomy

Intraperitoneal administration of local anaesthetics may reduce postoperative pain after ovariohysterectomy in dogs. The aim of this prospective, randomised, blinded, placebo-controlled clinical trial was to compare postoperative analgesia and opioid requirements after intraperitoneal and incisional administration of ropivacaine versus 0,9% NaCl (saline). Forty-three client-owned dogs were enrolled in the study and anaesthetised using a standardized protocol that included premedication with acepromazine (0,03–0,05mg/kg) and dexmedetomidine (0,01mg/kg) intramuscularly. Anaesthesia was induced with propofol titrated to effect and ketamine (1mg/kg) intravenously and maintained with isoflurane in oxygen. The analgesic regimen included carprofen (4mg/kg) subcutaneously and morphine (0,2mg/kg) intravenously. Depending on group assignment, each dog received either an intraperitoneal and incisional splash with ropivacaine (2mg/kg and 1mg/kg, respectively) (group R), or an equal volume of saline (group S). Buprenorphine (0,02mg/kg) was administered intramuscularly once the uterus was removed. Sedation and pain were assessed 0,5, 1, 2, 4, 6 and 8 hours after extubation using a sedation scale, the short form of the Glasgow Composite Pain Scale (CMPS-SF) and a dynamic interactive visual analogue scale (DIVAS). Postoperatively, buprenorphine (0,01mg/kg) was administered intravenously if dogs scored 6/24 on CMPS-SF.The ordinal mixed model showed no difference in pain scores between groups. Fisher’s exact test showed no significant difference in postoperative buprenorphine requirements between group S (3/22 dogs) and group R (1/21 dogs) at the doses used. In addition, lower sedation scores were associated with higher DIVAS scores. In this multimodal analgesic protocol, ropivacaine could not improve analgesia compared to saline

Evaluation of the Effect of Storage Time on ROTEM S® Parameters in Healthy and Ill Dogs.

Viscoelastic testing as a bedside test to assess global haemostasis has gained popularity in the past decade, with rotational thromboelastometry (ROTEM) and thromboelastography (TEG) being the two commonly used devices. TEG studies suggest analysis 30 min after blood sampling. However, the reproducibility of results over time for ROTEM analysis using lyophilized samples in dogs has not been established. In this study, we investigated the influence of time on viscoelastic testing, using 33 healthy staff-/client-owned dogs for blood sampling and repeated measurements of ROTEM tracings at three different time points after blood collection. Additionally, a group of 21 hospitalized patients with suspected coagulation disorders were included to investigate whether stability over time was comparable between healthy and ill dogs. We demonstrated a significant difference of ROTEM tracings over time, with a tendency towards hypocoagulability over time. These changes do have a clinical relevance as they exceed reference intervals and could therefore lead to erroneous conclusions about a patient's coagulation status. Therefore, time-specific reference intervals are proposed and presented in this publication

Evaluation of the Effect of Storage Time on ROTEM S® Parameters in Healthy and Ill Dogs

Viscoelastic testing as a bedside test to assess global haemostasis has gained popularity in the past decade, with rotational thromboelastometry (ROTEM) and thromboelastography (TEG) being the two commonly used devices. TEG studies suggest analysis 30 min after blood sampling. However, the reproducibility of results over time for ROTEM analysis using lyophilized samples in dogs has not been established. In this study, we investigated the influence of time on viscoelastic testing, using 33 healthy staff-/client-owned dogs for blood sampling and repeated measurements of ROTEM tracings at three different time points after blood collection. Additionally, a group of 21 hospitalized patients with suspected coagulation disorders were included to investigate whether stability over time was comparable between healthy and ill dogs. We demonstrated a significant difference of ROTEM tracings over time, with a tendency towards hypocoagulability over time. These changes do have a clinical relevance as they exceed reference intervals and could therefore lead to erroneous conclusions about a patient’s coagulation status. Therefore, time-specific reference intervals are proposed and presented in this publication