Evaluation of Electrical Cardiometry for Measuring Cardiac Output and Derived Hemodynamic Variables in Comparison with Lithium Dilution in Anesthetized Dogs.

Numerous cardiac output (CO) technologies were developed to replace the 'gold standard' pulmonary artery thermodilution due to its invasiveness and the risks associated with it. Minimally invasive lithium dilution (LiD) shows excellent agreement with thermodilution and can be used as a reference standard in animals. This study evaluated CO via noninvasive electrical cardiometry (EC) and acquired hemodynamic variables against CO measured using LiD in six healthy, anesthetized dogs administered different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. These treatments were chosen to cause drastic variations in CO, so that fair comparisons between EC and LiD across a wide range of CO values (low, intermediate, and high) could be made. Statistical analysis included linear regression, Bland-Altman plots, Lin's concordance correlation coefficient (ρc), and polar plots. Values of p < 0.05 represented significance. Good agreement was observed between EC and LiD, but consistent underestimation was noted when the CO values were high. The good trending ability, ρc of 0.88, and low percentage error of ±31% signified EC's favorable performance. Other EC-acquired variables successfully tracked changes in CO measured using LiD. EC may be a pivotal hemodynamic tool for continuously monitoring circulatory changes, as well as guiding and treating cardiovascular anesthetic complications in clinical settings.

Agreement of cardiac output measurements by esophageal Doppler and transesophageal echocardiography with intermittent pulmonary artery thermodilution during pharmacologic manipulation of hemodynamics in anesthetized dogs.

OBJECTIVE: To compare cardiac output (CO) measurements by transesophageal echocardiography (TEECO) and esophageal Doppler monitor (EDMCO) with pulmonary artery thermodilution (PATDCO) in anesthetized dogs subjected to pharmacological interventions. The effect of treatments on EDM-derived indexes was also investigated. ANIMALS: 6 healthy male dogs (10.8 ± 0.7 kg). METHODS: Dogs were anesthetized with propofol and isoflurane, mechanically ventilated, and monitored with invasive mean arterial pressure (MAP), end-tidal isoflurane concentration (ETISO), PATDCO, TEECO, EDMCO, and EDM-derived indexes. Four treatments were administered to all dogs by randomization. Baseline data were collected before each treatment: (1) dobutamine infusion; (2) esmolol infusion; (3) phenylephrine infusion; and (4) ETISO > 3%. Data were collected after 10-minute stabilization and after 30 minutes of washout between treatments. Statistical tests were pairwise t test, Bland-Altman analysis, Lin's concordance correlation (ρc), and polar plot analysis with P < .05 set as significance. RESULTS: The mean ± SD relative bias (limits of agreement) for TEECO was 0.35 ± 25.2% (-49.1% to 49.8%) and for EDMCO was -27.2 ± 22.5% (-71.4% to 17%) versus PATDCO. The percent error for TEECO and EDMCO was 27.6% and 44.1%, respectively. The ρc value was 0.82 for TEECO and 0.66 for EDMCO. TEECO and EDMCO showed good trending ability. EDM-derived indexes displayed significant changes specific to the drug administered (P < .001). CLINICAL RELEVANCE: For minimally invasive CO monitoring, TEE may provide more favorable performance than EDM in clinical settings; however, EDM-derived indexes yield valuable hemodynamic information that reliably follows trends in CO, thus supporting critical decision-making in canine patients.

Thalamic control of sensory processing and spindles in a biophysical somatosensory thalamoreticular circuit model of wakefulness and sleep.

Thalamoreticular circuitry plays a key role in arousal, attention, cognition, and sleep spindles, and is linked to several brain disorders. A detailed computational model of mouse somatosensory thalamus and thalamic reticular nucleus has been developed to capture the properties of over 14,000 neurons connected by 6 million synapses. The model recreates the biological connectivity of these neurons, and simulations of the model reproduce multiple experimental findings in different brain states. The model shows that inhibitory rebound produces frequency-selective enhancement of thalamic responses during wakefulness. We find that thalamic interactions are responsible for the characteristic waxing and waning of spindle oscillations. In addition, we find that changes in thalamic excitability control spindle frequency and their incidence. The model is made openly available to provide a new tool for studying the function and dysfunction of the thalamoreticular circuitry in various brain states.

Transpulmonary ultrasound dilution is an acceptable technique for cardiac output measurement in anesthetized pigs.

OBJECTIVE: To evaluate cardiac output (CO) measurements using transpulmonary ultrasound (TPUD) technology and compare results with those of the gold standard, pulmonary arterial catheter thermodilution (PACTD), in 6 healthy anesthetized pigs during acute hemodynamic changes caused by manipulation of the blood volume. ANIMALS: 6 healthy male Landrace pigs. PROCEDURES: Over a period of 1 week, pigs were anesthetized with isoflurane, mechanically ventilated, and underwent instrumentation in dorsal recumbency. They were subjected to sequential experimental states during which the blood volume was manipulated so that the animals transitioned from normovolemia to hypovolemia (20% and 40% of blood volume depletion), back to normovolemia (autologous blood transfusion), and then to hypervolemia (following colloid bolus). During each volume state, CO measurements were compared between TPUD and PACTD. RESULTS: The mean ± SD relative bias between TPUD and PACTD was 7.71% ± 21.2% with limits of agreement -33.9% to 49.3%, indicating TPUD slightly underestimated CO values, compared with values obtained with PACTD. The mean ± SD of the bias between the 2 methods was 0.13 ± 0.5 L/min. Only 5 of 36 (13.9%) TPUD CO measurements had an absolute value of relative bias > 30%. The percentage error calculated for TPUD was 29.4%. CLINICAL RELEVANCE: Results suggested that TPUD measurements have acceptable agreement with PACTD measurements. Moreover, TPUD exhibits promising potential in being used interchangeably with PACTD for future hemodynamic research involving swine as species of interest.

Ultrasound Findings and Laboratory Predictors of Early Mortality in Patients With Severe Yellow Fever.

OBJECTIVE. Yellow fever is a hemorrhagic disease caused by an arbovirus endemic in South America; outbreaks have occurred in recent years. The purpose of this study was to describe abdominal ultrasound findings in patients with severe yellow fever and correlate them with clinical and laboratory data. MATERIALS AND METHODS. A retrospective cohort study was performed between January and April 2018. The subjects were patients admitted to an ICU with polymerase chain reaction-confirmed yellow fever. Bedside sonography was performed within 48 hours of admission. Images were independently analyzed by two board-certified radiologists. Laboratory test samples were collected within 12 hours of image acquisition. Multivariable logistic regression analysis was performed to identify 30-day mortality predictors; p < .05 was considered statistically significant. RESULTS. Forty-six patients (40 [87%] men, six [13%] women; mean age, 47.5 ± 15.2 years) were evaluated with bedside sonography. Laboratory tests showed high serum levels of aspartate aminotransferase (5319 U/L), total bilirubin (6.2 mg/dL), and creati-nine (4.3 mg/dL). Twenty-six (56.5%) patients died within 30 days of admission (median time to death, 5 days [interquartile range, 2-9 days]). The most frequent ultrasound findings were gallbladder wall thickening (80.4%), increased renal cortex echogenicity (71.7%), increased liver parenchyma echogenicity (65.2%), perirenal fluid (52.2%), and ascites (30.4%). Increased renal echogenicity was associated with 30-day mortality (84.6% versus 55.0%; p = .046) and was an independent predictor of this outcome after multivariate analysis (odds ratio, 10.89; p = .048). CONCLUSION. Reproducible abdominal ultrasound findings in patients with severe yellow fever may be associated with severity of disease and prognosis among patients treated in the ICU.

Use of a modified passive leg-raising maneuver to predict fluid responsiveness during experimental induction and correction of hypovolemia in healthy isoflurane-anesthetized pigs.

OBJECTIVE To evaluate the use of a modified passive leg-raising maneuver (PLRM) to predict fluid responsiveness during experimental induction and correction of hypovolemia in isoflurane-anesthetized pigs. ANIMALS 6 healthy male Landrace pigs. PROCEDURES Pigs were anesthetized with isoflurane, positioned in dorsal recumbency, and instrumented. Following induction of a neuromuscular blockade, pigs were mechanically ventilated throughout 5 sequential experimental stages during which the blood volume was manipulated so that subjects transitioned from normovolemia (baseline) to hypovolemia (blood volume depletion, 20% and 40%), back to normovolemia, and then to hypervolemia. During each stage, hemodynamic variables were measured before and 3 minutes after a PLRM and 1 minute after the pelvic limbs were returned to their original position. The PLRM consisted of raising the pelvic limbs and caudal portion of the abdomen to a 15° angle relative to the horizontal plane. RESULTS Hemodynamic variables did not vary in response to the PLRM when pigs were normovolemic or hypervolemic. When pigs were hypovolemic, the PLRM resulted in a significant increase in cardiac output and decrease in plethysomographic variability index and pulse pressure variation. When the pelvic limbs were returned to their original position, cardiac output and pulse pressure variation rapidly returned to their pre-PLRM values, but the plethysomographic variability index did not. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested a modified PLRM might be useful for identification of hemodynamically unstable animals that are likely to respond to fluid therapy. Further research is necessary to validate the described PLRM for prediction of fluid responsiveness in clinically ill animals.

Effects of a single intravenous bolus injection of alfaxalone on canine splenic volume as determined by computed tomography.

The purpose of this study was to evaluate the effects of a single intravenous dose of alfaxalone on canine splenic volume. In 6 adult beagle dogs the splenic volume [mean ± standard error (SE)] was determined by computed tomography to be 0.17 ± 0.02 L before alfaxalone administration and 0.24 ± 0.02 L (P = 0.0091) and 0.23 ± 0.02 L (P = 0.0268) 15 and 30 min, respectively, after alfaxalone administration. Hematocrits (mean ± SE) obtained at the same times were, respectively, 46.3% ± 1.3%, 40.6% ± 1.3% (P = 0.0015), and 41.7% ± 1.3% (P = 0.0057). In conclusion, alfaxalone caused relaxation of the canine splenic capsule and an increase in the splenic volume, along with a decrease in the hematocrit in these dogs.

Le but de cette étude était d'évaluer les effets d'administration intraveineuse d'alfaxalone intraveineuse sur le volume splénique canin déterminé par la tomodensitométrie. Le volume de rate de 6 chiens beagle adultes a été déterminé par tomodensitométrie avant et après l'administration d'alfaxalone. Le volume splénique moyen (± erreur type) était 0,17 ± 0,02 L avant l'administration d'alfaxalone et 0,24 ± 0,02 L (P = 0,0091) et 0,23 ± 0,02 L (P = 0,0268) à 15 min et à 30 min après l'administration d'alfaxalone, respectivement. L'hématocrite moyen (± erreur type) était 46,3 % ± 1,3 % (SEM) avant l'administration d'alfaxalone et 40,6 % ± 1,3 % (P = 0,0015) et 41,7 % ± 1,3 % (P = 0,0057) à 15 min et à 30 min après l'injection. En conclusion, dans cette étude, l'alfaxalone a provoqué une relaxation de la capsule splénique canine et une augmentation de son volume avec une diminution de l'hématocrite.(Traduit par les auteurs).

Ultrasonographical identification of the superficial circumflex iliac artery as a landmark for location of the femoral nerve in dogs.

OBJECTIVE: To investigate the utility of identifying the superficial circumflex iliac artery (SCIA) via ultrasound as an anatomical landmark for ultrasound-guided femoral nerve block. STUDY DESIGN: Observational study. ANIMALS: A group of six canine cadavers weighing >20 kg. METHODS: Pelvic limbs from six canine cadavers were examined to study the relationship between the SCIA and the femoral nerve. Ultrasonographic imaging of the SCIA in each limb was obtained with the transducer placed transversely in the medial aspect of the pelvic limb at the inguinal area. Subsequently, a needle was inserted in close proximity to the femoral nerve using an in-plane technique based on the anatomical relationship between the SCIA and femoral nerve. A total of 0.1 mL of colored latex was then injected at the location where the femoral nerve was expected to be in relationship to the SCIA. Gross dissection of the inguinal region in each pelvic limb was performed after injection. Positive nerve location was defined when the colored latex was in contact with the femoral nerve. RESULTS: A total of eleven pelvic limbs were injected because the SCIA could not be successfully visualized in one limb. Upon dissection, colored latex was found to be in direct contact with the femoral nerve in all 11 injected limbs. CONCLUSIONS AND CLINICAL RELEVANCE: We concluded that the ultrasonographic visualization of the SCIA assisted in the accurate deposition of dye in proximity to the femoral nerve of canine cadavers. Further investigation will determine the efficacy of this technique for performing femoral nerve blocks.

Comparison of cardiac output measured by use of computed tomography and thermodilution in dogs.

OBJECTIVE To compare cardiac output (CO) measured by use of CT coronary angiography and thermodilution (criterion-referenced standard) at various CO values, record adverse effects, and determine the time needed to measure CO. ANIMALS 5 healthy purpose-bred Beagles (2 males and 3 females). PROCEDURES A prospective nonrandomized crossover study was conducted. Dogs were premedicated with butorphanol tartrate (0.2 mg•kg-1, IM). Anesthesia was induced by IV administration of etomidate (1 to 2 mg•kg-1) and midazolam (0.25 mg•kg-1). Orotracheal intubation was performed, and anesthesia was maintained by administration of isoflurane. The CO was determined by use of thermodilution and by use of CT at 3 CO values. Dobutamine was infused at various rates to obtain the 3 CO values. RESULTS 13 values were obtained and analyzed. The mean ± SD difference between methods was 0.09 ± 0.71 L•min-1 (95% confidence interval [CI], 0.52 to -0.34 L•min-1). Only 1 of 13 values was located on the 100% agreement line (ie, 0 line), 7 of 13 values were located within the 95% CI, and 5 of 13 values were outside the 95% CI. CONCLUSIONS AND CLINICAL RELEVANCE For this study, there was poor agreement between the 2 methods. The 95% CI interval was 0.52 to -0.34 L•min-1, and 5 of 13 values were outside the 95% CI. Therefore, results for the CT method appeared to be inappropriate for use in making clinical decisions.

Diagnostic usefulness of laparoscopy versus exploratory laparotomy for dogs with suspected gastrointestinal obstruction.

OBJECTIVE To evaluate the feasibility of laparoscopy versus exploratory laparotomy for the diagnosis of specific lesions in dogs with suspected gastrointestinal obstruction. DESIGN Controlled trial. ANIMALS 16 client-owned dogs with physical and radiographic findings consistent with gastrointestinal obstruction. PROCEDURES Single-incision laparoscopy with intracorporeal and extracorporeal examination of the gastrointestinal tract was performed by 1 surgeon. Immediately afterward, exploratory laparotomy was performed by a second surgeon. Accessibility and gross appearance of organs, surgical diagnoses, incision lengths, procedure duration, and complications were compared between diagnostic techniques. RESULTS Mean (95% confidence interval) incision length was 4.9 cm (3.9 to 5.9 cm) for laparoscopy and 16.4 cm (14.0 to 18.7 cm) for exploratory laparotomy. Mean (95% confidence interval) procedure duration was 36.8 minutes (31.6 to 41.2 minutes) and 12.8 minutes (11.4 to 14.3 minutes), respectively. Diagnoses of the cause of obstruction were the same with both methods. In 13 dogs, the laparoscopic examination was successfully completed, and in the other 3, it was incomplete. In 4 dogs in which laparoscopy was successful, conversion to exploratory laparotomy or considerable extension of the laparoscopic incision would have been required to allow subsequent surgical treatment of identified lesions. No dogs developed major complications, and minor complication rates were similar between procedures. CONCLUSIONS AND CLINICAL RELEVANCE Laparoscopy was feasible and clinically applicable in dogs with suspected gastrointestinal obstruction. Careful patient selection and liberal criteria for conversion to an open surgical approach are recommended when laparoscopy is considered for the diagnosis of gastrointestinal lesions in dogs.

Measurement of intraocular pressure in healthy anesthetized horses during hoisting.

OBJECTIVE: To measure intraocular pressure (IOP) in horses during hoisting after induction of anesthesia. STUDY DESIGN: Prospective nonrandomized clinical study. ANIMALS: Eighteen healthy adult horses aged [mean±standard deviation (SD)] 10±4.2 years and weighing 491±110 kg anesthetized for elective procedures. METHODS: IOP was measured in the superior eye of each horse based on planned recumbency after induction of anesthesia. Measurements were taken directly after premedication with xylazine or detomidine with butorphanol, after induction with diazepam-ketamine, after intubation, when suspended by the hoist and on the operating table. During hoisting, the head was supported and the eye-heart height was measured to account for variations in head positioning among patients. IOPs were compared across time points using repeated-measures analysis of variance. Regression was used to compare IOP outcome with potential cofactors. RESULTS: Compared with measurements after premedication (17.5±2.5 mmHg) (mean±SD), hoisting significantly increased IOP (32.4±15.3 mmHg) (p<0.01). The highest recorded IOP in the hoist was 80.0 (range, 16.0-80.0) mmHg. The difference in IOP between premedication and hoisting was 15.0±16.2 (range, -1.0 to 68.0) mmHg. Body weight had a significant effect on absolute IOP and change in IOP in the hoist (p<0.01). CONCLUSIONS AND CLINICAL RELEVANCE: Hoist IOP was significantly higher than post-premedication IOP with heavier horses having higher hoist IOPs and greater increases in IOP. The clinician should take this relationship into account when anesthetizing and hoisting larger horses where an increase in IOP could be detrimental.

Cardiac arrest in an American Cocker Spaniel during a deep ear flush procedure.

CASE DESCRIPTION A 14-year-old spayed female American Cocker Spaniel with bilateral otitis media and no evidence of cardiovascular instability was anesthetized to allow performance of a deep ear flush. CLINICAL FINDINGS Otoscopic examination of the left ear revealed evidence of chronic inflammation; the ear was flushed with sterile saline (0.9% NaCl) solution. Examination of the right ear revealed more severe chronic inflammation than in the left ear, including a ruptured tympanum (timing of rupture unknown). The right ear was flushed with sterile saline solution, and several drops of otic medication were instilled. During infusion of saline solution, the ECG revealed a rapid decrease in heart rate until no more electrical activity was noted. Pulse also ceased to be detectable via pulse oximetry and femoral artery palpation. TREATMENT AND OUTCOME Isoflurane was discontinued immediately after recognition of cardiac arrest. Shortly after, atropine (0.04 mg/kg [0.02 mg/lb]) and epinephrine (0.3 mg/kg [0.14 mg/lb]) were administered IV, chest compressions and ventilation were performed for 2 to 3 minutes, and 3 boluses (each 5 mL/kg) of lactated Ringer solution were administered IV. The dog was extubated 8 minutes after anesthesia was discontinued, and its recovery was monitored for the next 5 hours. No further incidents of cardiac arrest occurred after recovery from anesthesia. CLINICAL RELEVANCE This case represented a rarely documented potential complication associated with otic manipulation in a dog: cardiac arrest secondary to stimulation of the auricular branch of the vagus nerve. Veterinarians should be prepared for and warn clients of this possibility prior to otic flushing.

Eficácia e efeitos hemodinâmicos da anestesia raquidiana com ropivacaína isobárica, hipobárica ou hiperbárica em cães anestesiados com isofluorano / Efficacy and hemodynamic effects of spinal anesthesia with isobaric, hypobaric or hyperbaric ropivacaine in dogs anesthetized with isoflurane

O presente estudo objetivou avaliar a anestesia raquidiana com ropivacaína em cães alterando a baricidade do anestésico local, investigando as alterações hemodinâmicas e complicações. Foram utilizados seis cães, Beagle, 4 anos, submetidos a anestesia inalatória com isofluorano e aos tratamentos: Ghipo = anestesia raquidiana hipobárica (0,5 mL NaCl 0,9% + 0,5 mL ropivacaína 0,75%); Giso = anestesia raquidiana isobárica (0,5 mL NaCl 1,53% + 0,5 mL ropivacaína 0,75%); Ghiper = anestesia raquidiana hiperbárica (0,5 mL glicose 10% + 0,5 mL ropivacaína 0,75%). Após indução anestésica e manutenção com isofluorano, os animais foram posicionados em decúbito lateral direito para a passagem de um cateter de artéria pulmonar pela veia jugular esquerda. Após esse procedimento, a punção subaracnóide foi realizada entre L5-L6 com uma agulha espinhal 22G, seguida da administração de 1 mL de anestésico local em 1 min. Os animais foram mantidos por 60 minutos anestesiados em decúbito ventral. A FC, f, PAM, DC, PAPm e TºC apresentaram aumento progressivo em todos os grupos enquanto que a PCPm, apenas no GHIPO, aumentou ao longo de todos os momentos. O IRPT no GISO apresentou valores significativamente superiores no M1, M5 e M10 comparado aos demais grupos, exceto no M5, em que o GISO diferiu somente do GHIPER. O IRVP no GISO aumentou no M5 em comparação ao MB. Foram observados efeitos adversos como déficit motor unilateral, atonia vesical, excitação, dor aguda e quemose. De acordo com os dados obtidos no presente estudo pode-se concluir que os animais que receberam anestesia raquidiana com as soluções hiperbárica e isobárica apresentaram maior bloqueio motor comprovando que a baricidade influencia diretamente o tipo de fibra a ser bloqueada. A utilização de solução isobárica resulta em um bloqueio misto (motor e sensitivo). As alterações hemodinâmicas descritas na literatura como, bradicardia e hipotensão, não puderam ser evidenciadas neste estudo embora o volume de anestésico tenha sido baixo associado a influência dos efeitos do isofluorano. Em relação às complicações evidenciadas, sugere-se acompanhamento pós-anestésico dos animais submetidos à anestesia raquidiana a fim de que quaisquer alterações possam ser identificadas precocemente e tratadas.(AU)

The aim of the study was to assess hemodynamic changes and complications of spinal anesthesia with ropivacaine at different baricities. Six beagle dogs aged four years. The dogs were anesthetized with isoflurane and subjected to the following treatments: Ghypo = spinal anesthesia with hypobaric ropivacaine (0.5mL of 0.9% NaCl+0.5mL ropivacaine at 0.75%); Giso = isobaric spinal anesthesia (0.5mL of 0,906% NaCl+0.5mL ropivacaine at 0.75%); Ghyper = hyperbaric spinal anesthesia (0.5mL of 10% glucose+0.5mL ropivacaine at 0.75%). After induction to anesthesia and maintenance with isoflurane, animals were positioned in right lateral recumbency for pulmonary artery catheterization through the left jugular vein. Spinal anesthesia was carried out with injection of 1mL of local anesthetic using a 22G Quincke tip needle in the L5-L6 space along 1 minute. Dogs were maintained under inhalation anesthesia for 60 minutes in ventral recumbency. HR, FR, MAP, CO, mPAP and body temperature progressively increased in all groups, whereas PCWP increased only in GHYPO at all time points. The TPRI showed significantly higher values in GISO at M1, M5 and M10 compared to the other groups, except for M5, during which GISO differed only from GHYPER. The PVRI increased at M5 compared to MB in GISO. Side effects such as unilateral motor deficit, bladder atony, excitation, acute pain and chemosis were observed. The hemodynamic changes were not relevant, although inhalation anesthesia with isoflurane might have influenced the results. The changes observed in the study demonstrate that motor blockade is likely to be obtained with isobaric and hyperbaric ropivacaine, thereby confirming the influence of baricity on the type of nerve fibers on the spinal cord. The isobaric solution results in a mixed blockade (motor and sensory blockade). Hemodynamic changes such as hypotension and bradycardia were not evidenced in this study, although local anesthetics were administered in low volumes and together with isoflurane anesthesia. Regarding complications, post-anesthetic observation is warranted in order to identify and treat possible changes. Spinal anesthesia in the conditions studied did not cause hemodynamic changes in isoflurane-anesthetized dogs and is thus considered safe for routine practice, although a few complications are prone to occur.(AU)

Evaluation of epiduroscopy for detection of vertebral canal and spinal cord lesions in dogs.

OBJECTIVE To evaluate the potential usefulness of epiduroscopy for clinical diagnosis and treatment of vertebral canal and spinal cord lesions in dogs. SAMPLE Cadavers of 6 mixed-breed dogs. PROCEDURES Dogs were positioned in sternal recumbency, and an endoscope was introduced into the lumbosacral epidural space. A fiberscope (diameter, 0.9 mm; length, 30 cm) was used for 3 dogs, and a videoscope (diameter, 2.8 mm; length, 70 cm) was used for the other 3 dogs. Visibility and identities of anatomic structures were recorded, and maneuverability of the endoscopes was assessed. Extent of macroscopic tissue damage was evaluated by manual dissection of the vertebral canal at the end of the procedure. RESULTS Intermittent saline (0.9% NaCl) solution infusion, CO2 insufflation, and endoscope navigation improved visualization by separating the epidural fat from the anatomic structures of interest. Images obtained with the fiberscope were small and of poor quality, making identification of specific structures difficult. Maneuverability of the fiberscope was difficult, and target structures could not be reliably reached or identified. Maneuverability and image quality of the videoscope were superior, and spinal nerve roots, spinal dura mater, epidural fat, and blood vessels could be identified. Subsequent manual dissection of the vertebral canal revealed no gross damage in the spinal cord, nerve roots, or blood vessels. CONCLUSIONS AND CLINICAL RELEVANCE A 2.8-mm videoscope was successfully used to perform epiduroscopy through the lumbosacral space in canine cadavers. Additional refinement and evaluation of the technique in live dogs is necessary before its use can be recommended for clinical situations.

Temporary percutaneous T-fastener gastropexy and continuous decompressive gastrostomy in dogs with experimentally induced gastric dilatation.

OBJECTIVE To evaluate a percutaneous, continuous gastric decompression technique for dogs involving a temporary T-fastener gastropexy and self-retaining decompression catheter. ANIMALS 6 healthy male large-breed dogs. PROCEDURES Dogs were anesthetized and positioned in dorsal recumbency with slight left-lateral obliquity. The gastric lumen was insufflated endoscopically until tympany was evident. Three T-fasteners were placed percutaneously into the gastric lumen via the right lateral aspect of the abdomen, caudal to the 13th rib and lateral to the rectus abdominis muscle. Through the center of the T-fasteners, a 5F locking pigtail catheter was inserted into the gastric lumen and attached to a device measuring gas outflow and intragastric pressure. The stomach was insufflated to 23 mm Hg, air was allowed to passively drain from the catheter until intraluminal pressure reached 5 mm Hg for 3 cycles, and the catheter was removed. Dogs were hospitalized and monitored for 72 hours. RESULTS Mean ± SD catheter placement time was 3.3 ± 0.5 minutes. Mean intervals from catheter placement to a ≥ 50% decrease in intragastric pressure and to ≤ 6 mm Hg were 2.1 ± 1.3 minutes and 8.4 ± 5.1 minutes, respectively. After catheter removal, no gas or fluid leakage at the catheter site was visible laparoscopically or endoscopically. All dogs were clinically normal 72 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE The described technique was performed rapidly and provided continuous gastric decompression with no evidence of postoperative leakage in healthy dogs. Investigation is warranted to evaluate its effectiveness in dogs with gastric dilatation-volvulus.

Use of a perfusion index to confirm the presence of sciatic nerve blockade in dogs.

OBJECTIVES: To evaluate perfusion index (PI) as a determinant of regional nerve block success following sciatic nerve blockade with bupivacaine in dogs undergoing stifle surgery. STUDY DESIGN: Prospective clinical trial. ANIMALS: Ten adult dogs, aged 5.6 ± 2.6 years and weighing 36.9 ± 16.8 kg, undergoing a tibial plateau leveling osteotomy. METHODS: Dogs were premedicated with acepromazine (0.03 mg kg-1 ) and hydromorphone (0.1 mg kg-1 ) intramuscularly, and anesthetized with propofol (up to 4 mg kg-1 ) intravenously and isoflurane in oxygen. An ultrasound-guided femoral and sciatic (F+S) nerve block was performed on the surgical limb with bupivacaine (0.75%), 0.2 mL kg-1 at the femoral site and 0.3 mL kg-1 at the sciatic site, with a maximum volume of 10 mL per site. Physiological variables were recorded every 5 minutes throughout anesthesia. A pulse co-oximeter probe was placed between the third and fourth digits of both pelvic limbs, and the PI was recorded 5 minutes before infiltration with bupivacaine, immediately afterwards, and every 5 minutes for 30 minutes. Motor nerve conduction velocity (MNCV) of the sciatic nerve was performed on the surgical limb 5 minutes before and 20 minutes after bupivacaine administration to confirm nerve block. RESULTS: The PI of the surgical limb was significantly greater than the contralateral pelvic limb at 10 minutes (p = 0.03) and 15 minutes (p < 0.01) after F+S nerve blockade. The MNCV performed after sciatic nerve blockade revealed a functional motor blockade for all dogs. There were no significant changes in physiological variables. CONCLUSIONS AND CLINICAL RELEVANCE: The PI provided a reliable indication of successful sciatic nerve blockade in the clinical patients in this study. No increase in the PI by 15 minutes after bupivacaine administration around the sciatic nerve could indicate partial or total failure of anesthetic blockade.

Evaluation of surgical outcome, complications, and mortality in dogs undergoing preoperative computed tomography angiography for diagnosis of an extrahepatic portosystemic shunt: 124 cases (2005-2014).

This study evaluated the safety of preoperative computed tomography angiography (CTA) and its effect on surgical time and clinical outcomes in dogs that underwent surgical correction of a single congenital extrahepatic portosystemic shunt (CEPSS). Patient data were retrospectively collected from medical records and owner communications for 124 dogs with single CEPSS, undergoing preoperative CTA (n = 43) or not (n = 81) which were surgically treated from 2005 to 2014. The frequency of major postoperative complications was 4.7% and 9.9% for the CTA and no CTA groups, respectively (P = 0.49). Mean ± standard deviation (SD) surgical time for the preoperative CTA group was 84 ± 40 min and 81 ± 31 min for the no CTA group (P = 0.28). We conclude that anesthetized preoperative CTA appears to be a safe method for diagnosis and surgical planning in dogs with single CEPSS, and does not appear to affect surgical procedure time, complication rate, or clinical outcome.

Évaluation des résultats chirurgicaux, des complications et de la mortalité chez les chiens subissant une angiographie par tomodensitométrie préopératoire pour le diagnostic d'un shunt portosystémique extrahépatique : 124 cas (2005­2014). Cette étude a évalué l'innocuité d'une angiographie par tomodensitométrie (AT) préopératoire et son effet sur la durée de la chirurgie et les résultats cliniques chez les chiens qui avaient subi la correction chirurgicale d'un shunt portosystémique extrahépatique congénital simple (SPSEHC). Les données des patients ont été recueillies rétrospectivement dans les dossiers médicaux et lors de communications avec les propriétaires pour 124 chiens atteints d'un SPSEHC simple, qui subissaient une AT préopératoire (n = 43) ou non (n = 81), et qui avaient été traités par chirurgie entre 2005 et 2014. La fréquence des complications postopératoires majeures était de 4,7 % et de 9,9 % pour les groupes AT et sans AT, respectivement (P = 0,49). La durée moyenne ± SD de la chirurgie pour le groupe d'AT préopératoire était de 84 ± 40 minutes et de 81 ± 31 minutes pour le groupe sans AT (P = 0,28). Nous avons conclu que l'AT préopératoire semble être une méthode sûre pour le diagnostic et la planification chirurgicale des chiens ayant un SPSEHC simple et qu'elle ne semble pas affecter la durée de l'intervention, le taux de complication ou les résultats cliniques.(Traduit par Isabelle Vallières).

Utility of transesophageal electrocardiography to guide optimal placement of a transesophageal pacing catheter in dogs.

OBJECTIVE: To determine if the transesophageal atrial (A) wave amplitude or ventricular (V) wave amplitude can be used to guide optimal positioning of a transesophageal pacing catheter in dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Fourteen client owned healthy dogs with a median weight of 15.4 kg (IQR = 10.6-22.4) and a median age of 12 months (IQR = 6-12). MATERIALS AND METHODS: Transesophageal atrial pacing (TAP) using a 6 Fr pacing catheter was attempted in dogs under general anesthesia. The pacing catheter was inserted orally into the esophagus to a position caudal to the heart. With the pulse generator set at a rate 20 beats/minute(-1) above the intrinsic sinus rate, the catheter was slowly withdrawn until atrial pacing was noted on a surface electrocardiogram (ECG). Then the catheter was withdrawn in 1 cm increments until atrial capture was lost. Minimum pacing threshold (MPT) and transesophageal ECG were recorded at each site. Amplitudes of the A and V waves on transesophageal ECG were then measured and their relationship to MPT was evaluated. RESULTS: TAP was achieved in all dogs. In 9/14 dogs the site of lowest overall MPT was the same as the site of maximal A wave deflection. In dogs with at least three data points, linear regression analysis of the relationship between the estimated site of the lowest overall MPT compared to estimated site of the maximal A and V waveform amplitudes demonstrated a strong correlation (R(2) = 0.99). CONCLUSION AND CLINICAL RELEVANCE: Transesophageal ECG A and V waveforms were correlated to MPT and could be used to direct the placement of a pacing catheter. However, the technique was technically challenging and was not considered to be clinically useful to guide the placement of a pacing catheter.

Anesthesia and analgesia for standing equine surgery.

Morbidity and mortality rate in equine anesthesia is still unacceptably high. Thus it is critical contemplating whether the benefit of general anesthesia for a specific patient and procedure outweighs the risks. Sedative protocols that would allow performing diagnostic and surgical procedures with the patient remaining standing would therefore be ideal. Infusion of short-acting agents allows to rapidly achieve a titratable steady state of sedation. Supplementing sedatives and tranquilizers with systemic analgesic or regional anesthetic techniques (i.e. epidurals) facilitates standing surgical procedures. Multimodal analgesia would also provide superior analgesia with potentially fewer side effects than a single agent approach.

Modulation of mucosal/systemic antibody response after sublingual immunotherapy in mite-allergic children.

BACKGROUND: There have been no data on sublingual immunotherapy (SLIT) in Brazilian patients sensitized to house dust mites. This study aimed to evaluate the mucosal/systemic antibody response changes and clinical efficacy after SLIT using Dermatophagoides pteronyssinus (Dpt) allergens with or without bacterial extracts in mite-allergic Brazilian children. METHODS: Patients with allergic rhinitis and asthma were selected for a double-blind, placebo-controlled trial randomized to three groups: DPT (Dpt extract, n = 34), DPT+MRB (Dpt plus mixed respiratory bacterial extracts, n = 36), and Placebo (n = 32). Total symptom and medication scores for rhinitis/asthma, skin prick test (SPT) to Dpt, and measurements of Dpt-, Der p 1-, Der p 2-specific serum IgE, IgG4, IgG1, and specific salivary IgA were evaluated at baseline and after 12 and 18 months of treatment. RESULTS: A significant long-term decline in total symptom/medication scores was observed only in active groups (DTP and DPT+MRB). There was no significant change in SPT results in all groups. SLIT using Dpt allergen alone induced increased levels of serum IgG4 to Dpt, Der p 1, and Der p 2, serum IgG1 and salivary IgA to Dpt and Der p 1. SLIT with Dpt plus bacterial extracts was able to decrease IgE levels, particularly to Der p 2, to increase salivary IgA levels to Der p 1, but had no changes on specific IgG4 and IgG1 levels. CONCLUSIONS: All children undergoing SLIT showed clinical improvement, but a long-term reduction in symptom/medication scores with modulation of mucosal/systemic antibody responses were seen only in active groups (DPT and DPT+MRB).