Evaluation of an onco-diet on body composition and inflammatory status of dogs with mammary tumor-Pilot study.

A high-protein hypercaloric diet enriched with glutamine and omega-3 polyunsaturated fatty acids was called an onco-diet. The goal was to verify the modulation of the inflammatory response and body composition of female dogs with mammary tumor after mastectomy, during onco-diet consumption, using a randomized, double-blinded, clinical trial. Six bitches (average age of 8.6 years) were allocated into Control Group-diet without glutamine, EPA and DHA supplementation; and six bitches (10.0 years) were allocated into Test-diet enriched with glutamine and omega-3. Serum measurements of TNF-α, IL-6, IL-10, IGF-1, C-reactive protein and determination of body composition were performed at pre- and post-surgical times. Statistical tests were used to compare the nutrient intake and dietary effects on inflammatory variables between the diets. No differences in concentrations of different cytokines (p>0.05) and C-reactive protein (CRP) (p = 0.51) were observed between the groups. The test group had a higher concentration of IGF-1 (p<0.05), higher percentage of muscle mass (p<0.01) and lower body fat (p<0.01), but the difference was present from initial and throughout the study. Onco-diet, enriched with glutamine and omega-3, in the amounts evaluated in this study, was not sufficient to modulate the inflammation and body composition of female dogs with mammary tumors submitted to unilateral mastectomy.

Corrigendum: Intraoperative protective mechanical ventilation in dogs: A randomized clinical trial.

[This corrects the article DOI: 10.3389/fvets.2022.842613.].

Microcirculation assessment of dexmedetomidine constant rate infusion during anesthesia of dogs with sepsis from pyometra: a randomized clinical study.

OBJECTIVE: To compare dexmedetomidine and fentanyl constant rate infusions in anesthetic protocols for septic dogs with pyometra, using microcirculatory, hemodynamic and metabolic variables. STUDY DESIGN: Randomized clinical study. ANIMALS: A total of 33 dogs with pyometra with two or more systemic inflammatory response syndrome variables undergoing ovariohysterectomy. METHODS: Dogs were randomized into two groups: group DG, dexmedetomidine (3 µg kg-1 hour-1; 17 dogs) and group FG, fentanyl (5 µg kg-1 hour-1; 16 dogs) infused during isoflurane anesthesia and mechanical ventilation. Microcirculation flow index (MFI), total vessel density and De Backer score were assessed using orthogonal polarization spectral imaging at the sublingual site. Heart rate, invasive blood pressure, temperature, arterial blood gas analysis and lactate concentration were obtained at various time points. Variables were recorded at baseline (BL), immediately before (T0), 30 (T30) and 60 (T60) minutes after infusion, and 60 minutes after surgery. Data were analyzed using the Shapiro-Wilk test. To compare variables between groups, the unpaired Student t test was used. Comparison between evaluation time points was performed with two-way anova for repeated measures. Where statistical significance was detected, the Bonferroni post hoc test was used. RESULTS: MFI was significantly higher in group FG at T30. Mean arterial pressure at T30 was higher in group DG (89 ± 15 mmHg) than in group FG (72 ± 13 mmHg). Lactate concentrations were not significantly different between groups at each time point. Both groups had similar clinical outcomes (mortality, extubation time and occurrence of hypotension and bradyarrhythmias). CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine (3 µg kg-1 hour-1) without a loading dose can be included in the maintenance of anesthesia in dogs with pyometra and sepsis without compromising microcirculation and hemodynamic values when compared with fentanyl (5 µg kg-1 hour-1).

Computed Tomography Assessment of Tidal Lung Overinflation in Domestic Cats Undergoing Pressure-Controlled Mechanical Ventilation During General Anesthesia.

Objective: This study aimed to evaluate lung overinflation at different airway inspiratory pressure levels using computed tomography in cats undergoing general anesthesia. Study Design: Prospective laboratory study. Animals: A group of 17 healthy male cats, aged 1.9-4.5 years and weighing 3.5 ± 0.5 kg. Methods: Seventeen adult male cats were ventilated in pressure-controlled mode with airway pressure stepwise increased from 5 to 15 cmH2O in 2 cmH2O steps every 5 min and then stepwise decreased. The respiratory rate was set at 15 movements per min and end-expiratory pressure at zero (ZEEP). After 5 min in each inspiratory pressure step, a 4 s inspiratory pause was performed to obtain a thoracic juxta-diaphragmatic single slice helical CT image and to collect respiratory mechanics data and an arterial blood sample. Lung parenchyma aeration was defined as overinflated, normally-aerated, poorly-aerated, and non-aerated according to the CT attenuation number (-1,000 to -900 HU, -900 to -500 HU, -500 to -100 HU, and -100 to +100 HU, respectively). Result: At 5 cmH2O airway pressure, tidal volume was 6.7± 2.2 ml kg-1, 2.1% (0.3-6.3%) of the pulmonary parenchyma was overinflated and 84.9% (77.6%-87.6%) was normally inflated. Increases in airway pressure were associated with progressive distention of the lung parenchyma. At 15 cmH2O airway pressure, tidal volume increased to 31.5± 9.9 ml kg-1 (p < 0.001), overinflated pulmonary parenchyma increased to 28.4% (21.2-30.6%) (p < 0.001), while normally inflated parenchyma decreased 57.9% (53.4-62.8%) (p < 0.001). Tidal volume and overinflated lung fraction returned to baseline when airway pressure was decreased. A progressive decrease was observed in arterial carbon dioxide partial pressure (PaCO2) and end-tidal carbon dioxide (ETCO2) when the airway pressures were increased above 9 cmH2O (p < 0.001). The increase in airway pressure promoted an elevation in pH (p < 0.001). Conclusions and Clinical Relevance: Ventilation with 5 and 7 cmH2O of airway pressure prevents overinflation in healthy cats with highly compliant chest walls, despite presenting acidemia by respiratory acidosis. This fact can be controlled by increasing or decreasing respiratory rate and inspiratory time.

Intraoperative Protective Mechanical Ventilation in Dogs: A Randomized Clinical Trial.

Objective: To evaluate gas exchange, respiratory mechanics, and hemodynamic impact of mechanical ventilation with low tidal volume (VT) in dogs with the use of positive end-expiratory pressure (PEEP) or preceded by alveolar recruitment maneuver (ARM). Study Design: Prospective randomized clinical trial. Animals: Twenty-one healthy client-owned mesocephalic healthy dogs, 1-7 years old, weighing 10-20 kg, and body condition scores 4-6/9 admitted for periodontal treatment. Methods: Isoflurane-anesthetized dogs in dorsal recumbency were ventilated until 1 h with a volume-controlled ventilation mode using 8 mL kg-1 of VT. The dogs were distributed in 2 groups: in the ARM group, PEEP starts in 0 cmH2O, increasing gradually 5 cmH2O every 3 min, until reach 15 cmH2O and decreasing in the same steps until 5 cmH2O, maintaining this value until the end; and PEEP group, in which the pressure 5 cmH2O was instituted from the beginning of anesthesia and maintained the same level up to the end of the anesthesia. Cardiopulmonary, metabolic, oxygenation parameters, and respiratory mechanics were recorded after the anesthesia induction (baseline-BL), 15, 45, and 75 min after BL and during the recovery. Results: The ARM increased the static compliance (Cst) (15 min after baseline) when compared with baseline moment (24.9 ± 5.8 mL cmH20-1 vs. 20.7 ± 5.4 mL cmH20-1-p = 0.0364), oxygenation index (PaO2/FIO2) (505.6 ± 59.2 mmHg vs. 461.2 ± 41.0 mmHg-p = 0.0453) and reduced the shunt fraction (3.4 ± 2.4% vs. 5.5 ± 1.6%-p = 0.062). In the PEEP group, no statistical differences were observed concerning the variables evaluated. At the beginning of the evaluation, the driving pressure (DP) before ARM was significantly greater than all other evaluation time points (6.9 ± 1.8 cmH20). Conclusions and Clinical Relevance: The use of 8 mL kg-1 of VT and 5 cmH20 PEEP without ARM maintain adequate oxygenation and mechanical ventilation in dental surgeries for up to 1 h. The use of ARM slightly improved compliance and oxygenation during the maneuver.

Ozone Therapy in the Prevention of Dental Plaque Formation in Dogs.

This study aims to assess ozonized mineral oil ointment application as an antiplaque therapy for dogs. Domestic healthy dogs received dental scaling and polishing under general anesthesia. Under standard feeding and homecare during 7 days, 20 dogs were randomly placed into 2 different groups for dental treatment. The control group (CG) was given a single placebo application and the ozone group (O3G) received daily ozonized ointment application. The average age (CG = 4.4; O3G = 5.7 years old), body weight (CG = 15.7; O3G = 15.3 kg) and the gingivitis index obtained on the first day (D0) allowed initial homogeneity between the groups. The dental plaque index, including clinical and computerized analysis on the seventh day, was obtained from the buccal aspect of specific dental locations. Both analyses revealed significant statistical association between daily application of ozone and antiplaque effect. There was no evidence of toxicity during the study. These results suggest that ozone therapy may be an efficient adjuvant to conventional periodontal treatment in decreasing initial dental plaque formation.

Effects of a diet enriched with eicosapentaenoic, docosahexaenoic and glutamine on cytokines as immunological markers for systemic inflammation in bitches before and after ovariohysterectomy.

The post-operative period can generate immunological stress and can be modulated through supplementation with the omega-3 series of polyunsaturated fatty acids. This study aimed to evaluate the effects of diets enriched with high doses of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and glutamine on inflammatory mediators in dogs before and after ovariohysterectomy (OVH). Twelve female dogs were divided into two groups: group A was fed a commercial diet without the addition of EPA and DHA, and group B was fed an experimental diet enriched with EPA and DHA (0.2 g/100 kcal). Experimental diet intake initiated 21 days before surgery and continued until 30 days after OVH. Parameters measured were serum cytokines (TNF-α, IL-6 and IL-10), C-reactive protein (CRP), IGF-1, lymphoproliferation and body composition before and after surgery. Statistical analyses were performed with SAS software considering the effects of age and diet and their interactions, and means were compared by the Tukey test. There was no difference between groups in body weight (p = .682), lean mass (p = .101) and body fat (p = .103). There were no group differences in serum concentrations of TNF-α, IL-6, IL-10, IGF-1, CRP and the percentage of lymphocyte proliferation. However, a time effect for TNF-α was observed (p < .001), in which T0P (10 days after the surgical procedure) presented lower values of this cytokine when compared to the other evaluation time points; and interaction effects between group and time were observed for serum concentrations of IL-6 (p < .001) and IL-10 (p = .002). OVH procedure was not considered invasive enough to increase inflammatory cytokines after 30 days of surgery, as well as the dosage of the EPA and DHA used before and after the surgery did not modulate the inflammatory markers.

Cyclooxygenases 1 and 2 inhibition and analgesic efficacy of dipyrone at different doses or meloxicam in cats after ovariohysterectomy.

OBJECTIVE: To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficacy of dipyrone or meloxicam in cats undergoing elective ovariohysterectomy. STUDY DESIGN: Prospective, blinded, randomized, clinical study. ANIMALS: A total of 30 healthy young cats. METHODS: The cats were randomly assigned to three postoperative groups: D25 (dipyrone 25 mg kg-1 every 24 hours), D12.5 (dipyrone 12.5 mg kg-1 every 12 hours) and M (meloxicam 0.1 mg kg-1 every 24 hours). In the first 24 hours, the drugs were administered intravenously (IV), and then orally for 6 (dipyrone) or 3 days (meloxicam). Prostanoids thromboxane B2 and prostaglandin E2 concentrations served as indicators of COX activity and, with physiological variables and pain and sedation scores, were measured for 24 hours after first analgesic administration. Rescue analgesia (tramadol, 2 mg kg-1 IV) was provided if Glasgow feline composite measure pain scale (CMPS-Feline) ≥5. Laboratory tests included symmetric dimethylarginine and adverse effects were evaluated regularly up to 7 and 10 days after surgery, respectively. Parametric and nonparametric data were analyzed with two-way anova and Kruskal-Wallis tests, respectively (p < 0.05). RESULTS: In the first half hour after analgesic administration, COX-1 activity was close to zero and remained significantly lower than before drug administration for 24 hours in all groups. The inhibition of COX-2 activity was significant for 30 minutes in all groups and up to 4 hours in group M. No alterations in laboratory tests or significant adverse effects were observed. Pain scores and need for rescue analgesia did not differ statistically among groups. CONCLUSIONS: Dipyrone at both doses and meloxicam provided a nonselective inhibition of COX-1 and -2 activities and effective analgesia without causing significant adverse effects or laboratory tests alterations. CLINICAL RELEVANCE: Dipyrone at both doses provides equally effective analgesia without causing adverse effects in cats undergoing ovariohysterectomy.

Evaluation of hematologic, biochemical, and blood gas variables in stored canine packed red blood cells, and the impact of storage time on blood recipients.

BACKGROUND: Canine packed red blood cells (pRBCs) can be stored under refrigeration for several days; however, cellular metabolism remains active inside the units, thus producing substances that affect their quality. OBJECTIVES: We aimed to evaluate hematologic, biochemical, and blood gas variable alterations that occur in canine pRBCs during storage, and their effects on recipient clinicopathologic parameters. METHODS: The study was conducted in two phases. In phase I, 15 pRBC units containing CPDA-1 were stored for 28 days; samples were collected weekly from the units of days 0 to 28 to measure the packed cell volume (PCV), pH, partial pressure carbon dioxide (PCO2 ), partial pressure oxygen (PO2 ), concentrations of lactate and potassium, and the percent hemolysis. In phase II, another 22 canine pRBC units stored for different time periods (maximum of 21 days) were transfused, and the recipients were evaluated before and after transfusion for changes in clinical parameters (heart rate, respiratory rate, systolic arterial pressure, and rectal temperature) and hematologic variables (PCV, lactate and potassium concentrations, pH, PCO2 , the ratio of arterial oxygen partial pressure to fractional inspired oxygen [PO2 /FiO2 ] ratio, oxygen saturation [SaO2 ], base excess, and bicarbonate [HCO3 ]). RESULTS: In the pRBC units, the PCV increased from 70% to 78.33%, the lactate concentration increased 627%, the potassium concentration increased 183%, the percent hemolysis reached 0.69%, and the pH decreased 9% after 28 days. However, the dogs who received transfusions were not negatively affected. There was a significant increase in PCVs, and a significant decrease in heart rates. CONCLUSION: Canine pRBCs undergo hematologic, blood gas, and biochemical alterations during storage; however, the transfusion of pRBCs stored for up to 21 days increased PCVs without causing harm to the dogs.

Ultrasound-guided continuous block of median and ulnar nerves in horses: development of the technique.

OBJECTIVE: To develop a technique for ultrasound-guided continuous median and ulnar peripheral nerve block in horses. STUDY DESIGN: Anatomical and prospective experimental study. ANIMALS: A total of 16 thoracic limbs from horse cadavers and 18 adult horses. METHOD: This study was conducted in three phases. Phase 1: Dissection of median and ulnar nerves in the antebrachial region of two cadaver limbs to identify localizing landmarks. Description of sonoanatomy in 14 cadaver limbs using ultrasound-guided perineural infiltration of a combination of cellulose gel (5 mL), contrast medium (4 mL) and methylene blue (1 mL). Catheters were inserted between the perineural sheath and epineurium in six limbs, followed by computed tomography. Phase 2: Ultrasonographic images of the limbs of 18 healthy horses of different breeds were used to define an acoustic window and optimize the approach to nerves. Phase 3: Two case reports of horses with chronic pain of different etiologies. Catheters were inserted between the epineurium and paraneural sheath of the median and/or ulnar nerves guided by ultrasound, followed by continuous infusion of 0.4% ropivacaine. RESULTS: Information from phase 1 was used to direct needle insertion, solution dispersion and catheter implantation in phase 2, which resulted in 100% technique accuracy. In response to the peripheral nerve block, pain reduction was apparent in the two clinical cases by increased weight bearing in affected limbs and decreased requirement for systemic analgesic medications. No local reactions were observed. CONCLUSIONS AND CLINICAL RELEVANCE: The ultrasound technique allowed real-time visualization of needle, catheter and drug dispersion and resulted in a high success rate for nerve blocks. The horses administered a median and ulnar nerve block exhibited no discomfort or signs of infection at the catheter insertion site. Further studies are warranted to validate the efficacy of this technique.

Combination of ketamine and xylazine with opioids and acepromazine in rats: Physiological changes and their analgesic effect analysed by ultrasonic vocalization.

In this study, the effect of four anaesthetic protocols that included the combination of xylazine (X) and ketamine (K) with acepromazine (A) and opioids (methadone (Me), morphine (Mo) or tramadol (T)) was evaluated in laboratory rats of both sexes. Ultrasonic vocalization (USV) was used as an indicator of pain during the recovery period. The objective was to evaluate the physiological parameters and the analgesic effect of each protocol to determine which protocol was the safest and fulfil the requirements of a balanced anaesthesia. The better protocols were the XKA protocol for both sexes and the XKMe protocol for females because the combinations achieve surgical plane of anaesthesia in rats. However, pain assessment during the formalin test revealed that rats anaesthetized with XKA produced more numbers of USV, suggesting that it is not a good protocol for the control of immediate postoperative pain. All protocols produced depression in body temperature and respiratory and heart rates, and had important effects, such as micturition and maintenance of open eyes. Only rats anaesthetized with XKA protocol did not present piloerection. These results demonstrated that good monitoring and care during anaesthesia must be included to prevent complications that compromise the life of the animal and to ensure a good recovery. The inclusion of analgesia in anaesthesia protocols must be used routinely, ensuring minimal presence of pain and thus more reliable results in the experimental procedures.

Comparison of pulse pressure variation versus echocardiography-derived stroke volume variation for prediction of fluid responsiveness in mechanically ventilated anesthetized dogs.

OBJECTIVE: To evaluate the ability and accuracy of aortic flow velocity-time integral variation (ΔVTI) and peak aortic velocity variation (ΔVpeak) compared with pulse pressure variation (PPV) to predict fluid responsiveness in mechanically ventilated dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: A group of 50 mechanically ventilated dogs with spontaneous hypotension during orthopedic or oncologic surgery. METHODS: Investigations were performed in the surgery room. When mean arterial pressure (MAP) decreased to <65 mmHg, measurements were performed before and after a fluid challenge (lactated Ringer's solution 5 mL kg-1 over 15 minutes). Responders were defined as a change in stroke volume (SV; transesophageal Doppler) ≥15%. Data were analyzed using paired/unpaired t test or Mann-Whitney/Wilcoxon test when appropriate and receiver operating characteristics (ROC) curves; a p value <0.05 was considered statistically significant. RESULTS: After the fluid challenge, 35 (70%) of 50 dogs were responders with significant increases in SV and decreases in PPV; 15 dogs were nonresponders. ΔVTI and ΔVpeak correlated with a 15% increase in SV. The optimum cut-off value for PPV was 15.6% (sensitivity, 88%; specificity, 100%), for ΔVTI was 10.65% (sensitivity, 65%; specificity, 100%) and for ΔVpeak was 10.15% (sensitivity, 80%; specificity, 100%). The area under the ROC curve for PPV was (0.93 ± 0.08) and for ΔVpeak was (0.89 ± 0.09), before fluid challenge. The gray zone area spread from 6.15% to 15.6% for PPV (18 dogs), 2.45% to 10.65% for ΔVTI (22 dogs) and 0.6% to 10.15% for ΔVpeak (25 dogs). CONCLUSIONS: When using mechanical ventilation, ΔVTI and ΔVpeak predicted fluid responsiveness with the same ability as PPV, based on the area under the ROC curve analysis. However, PPV showed great accuracy demonstrated by a narrower gray zone that included fewer individuals. CLINICAL RELEVANCE: ΔVTI and ΔVpeak can be used as indices of fluid responsiveness in anesthetized dogs.

Effects of 12 and 17 cmH2O positive end-expiratory pressure applied after alveolar recruitment maneuver on pulmonary gas exchange and compliance in isoflurane-anesthetized horses.

OBJECTIVE: To compare static compliance (Cst) and alveolar-arterial oxygen tension difference [P(a-a)O2] between positive end-expiratory pressures (PEEP) of 7, 12 and 17 cmH2O applied after an alveolar recruitment maneuver (RM) in isoflurane-anesthetized horses. STUDY DESIGN: Prospective, randomized, clinical study. ANIMALS: A group of 30 healthy adult horses undergoing arthroscopic surgery. METHODS: Animals in dorsal recumbency and mechanically ventilated with a tidal volume of 14 mL kg-1 and 7 cmH2O PEEP (control; n = 6) were subjected to an RM by increasing PEEP from 7 to 22 cmH2O in 5 cmH2O increments at 5 minute intervals, and then decreased similarly to PEEP of 17 (RM17; n = 8), 12 (RM12; n = 8) or 7 cmH2O (RM7; n = 8). Cst and P(a-a)O2 were assessed prior to (baseline) and after the RM at 5, 10, 15, 20, 40, 60 and 80 minutes after achieving each target PEEP, and during recovery from anesthesia. RESULTS: Post-RM improvements on P(a-a)O2 were maintained (baseline versus 80 minutes) in RM12 [216 ± 77 mmHg (28.8 ± 10.3 kPa) versus 194 ± 39 mmHg (25.9 ± 5.2 kPa)] and RM17 [180 ± 86 mmHg (24.0 ± 11.6 kPa) versus 136 ± 75 mmHg [18.2 ± 10.0 kPa]). The improvements on Cst were maintained only in RM12 (0.80 ± 0.13 versus 0.98 ± 0.13 mL cmH2O-1 kg-1). No such improvements were observed in RM7 and control. No significant differences were observed between groups during recovery from anesthesia. CONCLUSIONS: and clinical relevance The 12 and 17 cmH2O PEEP can be used to maintain the improvements on P(a-a)O2 obtained after an RM. Only 12 cmH2O PEEP maintained the post-RM increase on Cst. Such variables were not influenced by the 7 cmH2O PEEP.

Postoperative pain and short-term complications after two elective sterilization techniques: ovariohysterectomy or ovariectomy in cats.

BACKGROUND: Surgical sterilization of cats is one of the most commonly performed procedures in veterinary practice and it can be accomplished by two different techniques: ovariohysterectomy (OVH) or ovariectomy (OVE). Although there is an apparent preference for OVH in United States and Canada, OVE seems to be the standard of care in many European countries due to its advantages, such as a smaller surgical incision and potentially less complications associated with surgical manipulation of the uterus. The aim of this randomized, blind, prospective study was to compare postoperative pain and short-term complications in cats undergoing ovariohysterectomy or ovariectomy. METHODS: Twenty female cats were randomly assigned into two groups (OVH, n = 10 and OVE, n = 10). Pain was assessed prior to surgery (baseline) and 1, 2, 4, 8 12 and 24 h after the procedure using pain and sedation scales, physiologic parameters and blood glucose levels. Short-term complications were evaluated in the early postoperative period and reassessed at day 7 and day 10. RESULTS: Changes in cardiovascular parameters were not clinically relevant, however cats in OVH group had higher heart rates at T1 h compared with baseline (p = 0.0184). Blood glucose levels in OVH group were also higher at T1 h compared with baseline (p = 0.0135) and with OVE group (p = 0.0218). Surgical time was higher in OVH group (p = 0.0115). Even though no significant differences in pain scores were observed between groups or time points, cats in OVH group had greater need for rescue analgesia compared with OVE (2/10 and 0/10, respectively). Complications were not observed in any cat during surgery, at days 7 and 10 postoperatively or at discharge. CONCLUSIONS: Both surgical techniques promoted similar intensity of postoperative pain in cats and there were no short-term complications throughout the study's evaluation period. Therefore, both techniques may be indicated for surgical sterilization of cats, according to the surgeon's preference and expertise. Cats that underwent ovariectomy did not require rescue analgesia and surgical time was shorter in that group.

Clinical monitoring of cardiac output assessed by transoesophageal echocardiography in anaesthetised dogs: a comparison with the thermodilution technique.

BACKGROUND: Cardiac output (CO) is an important haemodynamic parameter to monitor in patients during surgery. However, the majority of the techniques for measuring CO have a limited application in veterinary practice due to their invasive approach and associated complexity and risks. Transoesophageal echocardiography (TEE) is a technique used to monitor cardiac function in human patients during surgical procedures and allows CO to be measured non-invasively. This prospective clinical study aimed to compare the transoesophageal echocardiography using a transgastric view of the left ventricular outflow tract (LVOT) and the thermodilution (TD) technique for the assessment of CO during mean arterial pressure of 65-80 mmHg (normotension) and <65 mmHg (hypotension) in dogs undergoing elective surgery. Eight dogs were pre-medicated with acepromazine (0.05 mg/kg, IM), tramadol (4 mg/kg, IM) and atropine (0.03 mg/kg, IM), followed by anaesthetic induction with propofol (3-5 mg/kg IV) and maintenance with isoflurane associated with a continuous infusion rate of fentanyl (bolus of 3 µg/kg followed by 0.3 µg/kg/min). The CO was measured by TEE (COTEE) and TD (COTD) at the end of expiration during normotension and hypotension (induced by isoflurane). RESULTS: There was a strong positive correlation between COTEE and COTD ​​(r = 0.925; P < 0.0001). The bias between COTD and COTEE was 0.14 ± 0.29 L/min (limits of agreement, -0.44 to 0.72 L/min). The percentage error of CO measured by the two methods was 12.32%. In addition, a strong positive correlation was found between COTEE and COTD during normotension (r = 0.995; P < 0.0001) and hypotension (r = 0.78; P = 0.0223). CONCLUSIONS: The results of this study indicated that the transgastric view of the LVOT by TEE was a minimally invasive alternative to clinically monitoring CO in dogs during anaesthesia. However, during hypotension, the CO obtained by TEE was less reliable, although still acceptable.

Pulse pressure variation as a guide for volume expansion in dogs undergoing orthopedic surgery.

OBJECTIVE: To investigate whether pulse pressure variation (PPV) can predict fluid responsiveness in healthy dogs during clinical surgery. STUDY DESIGN: Prospective clinical study. ANIMALS: Thirty-three isoflurane-anesthetized dogs with arterial hypotension during orthopedic surgery. METHODS: Fluid challenge with lactated Ringer's solution (15 mL kg-1 in 15 minutes) was administered in mechanically ventilated dogs (tidal volume 10 mL kg-1) with hypotension [mean arterial pressure (MAP) < 65 mmHg]. The volume expansion was considered effective if cardiac output (CO; transesophageal Doppler) increased by ≥ 15%. Cardiopulmonary data were analyzed using two-way ANOVA, receiver operating characteristics (ROC) curves and Spearman coefficient; p < 0.05 was considered significant. RESULTS: Effective volume expansion, mean ± standard deviation 42 ± 4% increase in CO (p < 0.0001) was observed in 76% of the dogs, resulting in a decrease in PPV (p < 0.0001) and increase in MAP (p < 0.0001), central venous pressure (CVP; p = 0.02) and ejection fraction (p < 0.0001) compared with before the fluid challenge. None of these changes occurred when volume expansion resulted in a nonsignificant CO increase of 4 ± 5%. No significant differences were observed in blood gas analysis between responsive and nonresponsive dogs. The increase in CO was correlated with the decrease in PPV (r = -0.65; p < 0.0001) but absolute values of CO and PPV were not correlated. The PPV performance (ROC curve area: 0.89 ± 0.06, p = 0.0011) was better than that of CVP (ROC curve area: 0.54 ± 0.12) and MAP (ROC curve area: 0.59 ± 0.13) to predict fluid responsiveness. The best cut-off for PPV to distinguish responders and nonresponders was 15% (50% sensitivity and 96% specificity). CONCLUSIONS AND CLINICAL RELEVANCE: In mechanically ventilated, healthy, isoflurane-anesthetized dogs, PPV predicted fluid responsiveness to volume expansion, and MAP and CVP did not show such applicability.

Ventilation distribution assessed with electrical impedance tomography and the influence of tidal volume, recruitment and positive end-expiratory pressure in isoflurane-anesthetized dogs.

OBJECTIVE: To examine the intrapulmonary gas distribution of low and high tidal volumes (VT) and to investigate whether this is altered by an alveolar recruitment maneuver (ARM) and 5 cmH2O positive end-expiratory pressure (PEEP) during anesthesia. STUDY DESIGN: Prospective randomized clinical study. ANIMALS: Fourteen client-owned bitches weighing 26 ± 7 kg undergoing elective ovariohysterectomy. METHODS: Isoflurane-anesthetized dogs in dorsal recumbency were ventilated with 0 cmH2O PEEP and pressure-controlled ventilation by adjusting the peak inspiratory pressure (PIP) to achieve a low (7 mL kg-1; n = 7) or a high (12 mL kg-1; n = 7) VT. Ninety minutes after induction (T90), an ARM (PIP 20 cmH2O for 10 seconds, twice with a 10 second interval) was performed followed by the application of 5 cmH2O PEEP for 35 minutes (RM35). The vertical (ventral=0%; dorsal=100%) and horizontal (right=0%; left=100%) center of ventilation (CoV), four regions of interest (ROI) (ventral, central-ventral, central-dorsal, dorsal) identified in electrical impedance tomography images, and cardiopulmonary data were analyzed using two-way repeated measures anova. RESULTS: The low VT was centered in more ventral (nondependent) areas compared with high VT at T90 (CoV: 38.8 ± 2.5% versus 44.6 ± 7.2%; p = 0.0325). The ARM and PEEP shifted the CoV towards dorsal (dependent) areas only during high VT (50.5 ± 7.9% versus 41.1 ± 2.8% during low VT, p = 0.0108), which was more distributed to the central-dorsal ROI compared with low VT (p = 0.0046). The horizontal CoV was centrally distributed and cardiovascular variables remained unchanged throughout regardless of the VT, ARM, and PEEP. CONCLUSIONS AND CLINICAL RELEVANCE: Both low and high VT were poorly distributed to dorsal dependent regions, where ventilation was improved following the current ARM and PEEP only during high VT. Studies on the role of high VT on pulmonary complications are required.

Distribution of bupivacaine hydrochloride after sciatic and femoral nerve blocks in cats: A magnetic resonance imaging study.

The objective of this study was to evaluate the distribution of bupivacaine hydrochloride using magnetic resonance imaging (MRI) after electrical nerve stimulator (ENS)-guided sciatic (ScN) and femoral (FN) nerve blocks in cats. Six adult cats (body weight 4.8±0.6kg) were anesthetized with acepromazine-buprenorphine-propofol-isoflurane. Transverse and sagittal plan sequences of pelvic limbs were obtained using a high-field magnet (1.5T). Afterwards, the ScN and FN blocks (one block per limb) were performed using 0.1mL/kg of bupivacaine 0.5% per site and the MRI sequence was repeated after each block. The injection was considered successful when bupivacaine was in contact with the nerve. Injectate location and complications were recorded. The length (mm) of contact (spread) between bupivacaine and nerves was measured and classified as fair (<15mm) or adequate (≥15mm). Five out of six ScN injections were successful; of these, four had adequate spread over the nerve [26 (13-39) mm]. All FN injections were successful, but in one case bupivacaine was administered over the motor branch of FN, distally to the bifurcation between the femoral and saphenous nerve. It was not possible to measure neither the length of contact between bupivacaine and FN nor to identify iatrogenic trauma caused by the injections. MRI can be used for the evaluation of bupivacaine distribution, but not complications, following ENS-guided ScN and FN blocks in cats. Despite most of the injections were considered successful, individual variability regarding the injectate location may explain differences in efficacy in the clinical setting.

A comparison of the cardiopulmonary effects of pressure controlled ventilation and volume controlled ventilation in healthy anesthetized dogs.

OBJECTIVE: To compare the effects of pressure controlled ventilation (PCV) with volume-controlled ventilation (VCV) on lung compliance, gas exchange, and hemodynamics in isoflurane-anesthetized dogs. DESIGN: Prospective randomized study. SETTING: Veterinary teaching hospital. ANIMALS: Forty client-owned bitches undergoing elective ovariohysterectomy. INTERVENTIONS: Dogs were randomly assigned to be ventilated with 100% oxygen using PCV (n = 20) or VCV (n = 20). The respiratory rate was 20/min and positive end-expiratory pressure (PEEP) was 5 cm H2 O, with a tidal volume of 10 mL/kg. Cardiac output (CO) was measured using thermodilution. Cardiopulmonary and blood gas data were obtained during spontaneous ventilation and after 30 (T30) and 60 minutes (T60) of controlled ventilation. MEASUREMENTS AND MAIN RESULTS: In dogs ventilated with PCV, at T30 and T60, PIP was lower (11.4 ± 1.9 and 11.1 ± 1.5 cm H2 O, respectively) and static compliance (CST ) was higher (51 ± 7 and 56 ± 6 mL/cm H2 O, respectively) than in VCV group (PIP of 14.3 ± 1.3 and 15.5 ± 1.4 cm H2 O; CST of 34 ± 8 and 33 ± 9 mL/cm H2 O, P < 0.0001). Compared with spontaneous ventilation, both groups had decreased alveolar-arterial oxygen difference at T30 and T60 (PCV: 128 ± 32 mm Hg vs 108 ± 20 and 104 ± 16 mm Hg, respectively; VCV: 131 ± 38 mm Hg vs 109 ± 19 and 107 ± 14 mm Hg, respectively; P < 0.01), while CO was maintained at all time points. CONCLUSIONS: Compared to spontaneous ventilation, both ventilatory modes effectively improved gas exchange without hemodynamic impairment. PCV resulted in higher lung CST and lower PIP compared to VCV.

Prevalence of Neoplastic Diseases in Pet Birds Referred for Surgical Procedures.

Neoplastic disease is common in pet birds, particularly in psittacines, and treatment should be primarily aimed at tumor eradication. Nineteen cases of pet birds submitted to diagnostic and/or therapeutic surgical procedures due to neoplastic disease characterized by the presence of visible masses were retrospectively analyzed; affected species, types of neoplasms and respective locations, and outcomes of surgical procedures were determined. All birds undergoing surgery belonged to the order Psittaciformes; the Blue-fronted parrot (Amazona aestiva) was the prevalent species. Lipoma was the most frequent neoplasm in the sample studied. Most neoplasms affected the integumentary system, particularly the pericloacal area. Tumor resection was the most common surgical procedure performed, with high resolution and low recurrence rates.