Sildenafil does not have a significant effect on the portal vein velocity, cross-sectional area, and congestion index in the dog

In veterinary medicine, sildenafil is most frequently used to treat pulmonary hypertension, but has also been investigated and used as a treatment for congenital megaesophagus and ischemic infarcts. With the increasing use, the effects of sildenafil on the portal vasculature in the dog have not been previously evaluated. The purpose of this study was to evaluate the effects sildenafil has on the portal vasculature, which anecdotally may have caused decreased portal vein pressure in an adult dog. The ultrasound cross-sectional area of the aorta, cross-sectional area of the portal vein, and portal vein blood flow velocity were acquired in dogs prior to administration, and 45, 90, and 120 min after oral administration of sildenafil for the treatment of pulmonary hypertension. Thirteen dogs were enrolled in the study. No statistically significant difference was detected between all measured values and the congestion index at all time points. A trend was identified that demonstrated progressively lower portal vein velocity with each evaluation, but this was not significant. Although this study had a small sample size, sildenafil was not shown to have a significant effect on the size or blood flow velocity of the portal vasculature. The hepatic buffer system, designed to maintain a constant blood flow to the liver, may be a contributing factor, but further studies with a larger sample size will be required for further evaluation.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Intraoperative Ultrasound Applications in Intracranial Surgery

The methods and use of intraoperative ultrasound in 33 canine and five feline patients and its ability to localize and identify anatomical structures and pathological lesions in canines and felines undergoing intracranial surgery are described from a case series. All were client-owned referral patients admitted for neurologic evaluation, with an advanced imaging diagnosis of an intracranial lesion, and underwent surgical biopsy or surgical removal of the lesion. Medical records, retrieval and review of imaging reports, and characterization of findings for all canine and feline patients show that intraoperative ultrasound guidance was used in intracranial procedures during the period of 2012 and 2019. Twenty-nine of the canine patients had intracranial tumors. The remainder had various other conditions requiring intracranial intervention. Three of the feline patients had meningiomas, one had a depressed skull fracture, and one had an epidural hematoma. The tumors appeared hyperechoic on intraoperative ultrasound with the exception of cystic portions of the masses and correlated with the size and location seen on advanced imaging. Statistical comparison of the size of images seen on ultrasound and on MRI for 20 of the canine tumors revealed no statistical differences. Neuroanatomical structures, including vascular components, were easily identified, and tumor images correlated well with preoperative advanced imaging. The authors conclude that intraoperative ultrasound is a valuable asset in intracranial mass removals and can augment surgical guidance in a variety of intracranial disorders that require surgery. This is the first known publication in veterinary surgery of using intraoperative ultrasound as a tool in the operating theater to identify, localize, and monitor the removal/biopsy of intracranial lesions in small animals undergoing craniotomy/craniectomy.

Sedation with dexmedetomidine is associated with transient gallbladder wall thickening and peritoneal effusion in some dogs undergoing abdominal ultrasonography

Background

Dexmedetomidine often is used for sedation before or during abdominal ultrasonography. The effect of dexmedetomidine on gallbladder wall thickness is unknown.

Hypothesis/Objectives

To investigate the relationship between dexmedetomidine administration and gallbladder wall thickening in dogs. The hypothesis was that sedation with dexmedetomidine will cause transient gallbladder wall thickening. Gallbladder wall thickness will be associated with duration of sedation and recumbency position.

Animals

Seventy‐nine client owned dogs and 10 healthy research dogs.

Methods

A prospective observational study (n = 79) was used to establish the prevalence of gallbladder wall thickening (> 2.0 mm) after sedation with dexmedetomidine. A randomized, crossover study (n = 10) was used to evaluate the effect of time and recumbency position on the development of gallbladder wall thickening. Linear mixed models were used.

Results

The proportion of client‐owned dogs that developed gallbladder wall thickening was 24.05% (19/79; 95% confidence interval [CI], 15.1%‐35.0%) with a median dose of dexmedetomidine of 5.0 μg/kg (range, 2.0‐12.5 μg/kg). After sedation, the proportion of research dogs that developed gallbladder wall thickening in left lateral (5/10, 50%; 95% CI, 18.7%‐81.3%) and dorsal (7/10, 70%; 95% CI, 34.8%‐93.3%) recumbency did not differ significantly (P = .45). Gallbladder wall thickening developed within 20 to 40 minutes. Duration of sedation was significantly associated with thickening of the gallbladder wall (P < .001). Five dogs developed 9 instances of peritoneal effusion in both lateral (5) and dorsal (4) recumbency.

Conclusions and Clinical Importance

Sedation with dexmedetomidine is associated with gallbladder wall thickening (> 2.0 mm) and peritoneal effusion that could be confused with pathologic etiologies.

Innovations in osteomyelitis research: A review of animal models

Infection of bone tissue, or osteomyelitis, has become a growing concern in modern healthcare due in no small part to a rise in antibiotic resistance among bacteria, notably Staphylococcus aureus. The current standard of care involves aggressive, prolonged antibiotic therapy combined with surgical debridement of infected tissues. While this treatment may be sufficient for resolving a portion of cases, recurrences of the infection and associated risks including toxicity with long-term antibiotic usage have been reported. Therefore, there exists a need to produce safer, more efficacious options of treatment for osteomyelitis. In order to test treatment regimens, animal models that closely mimic the clinical condition and allow for accurate evaluation of therapeutics are necessary. Establishing a model that replicates features of osteomyelitis in humans continues to be a challenge to scientists, as there are many variables involved, including choosing an appropriate species and method to establish infection. This review addresses the refinement of animal models of osteomyelitis to reflect the clinical disease and test prospective therapeutics. The aim of this review is to explore studies regarding the use of animals for osteomyelitis therapeutics research and encourage further development of such animal models for the translation of results from the animal experiment to human medicine.

Persistent gross lipemia and suspected corneal lipidosis following intravenous lipid therapy in a cat with permethrin toxicosis

OBJECTIVE

To describe the observation of persistent gross lipemia and suspected corneal lipidosis following intravenous lipid therapy (IVLT) in a cat with permethrin toxicosis.

CASE SUMMARY

A 5-year-old, spayed female, domestic short-haired cat with permethrin toxicosis was treated with a high dose of IVLT as an adjunct treatment when it remained severely obtunded following traditional supportive care. The cat received intravenous 20% lipid emulsion as a 1.5 mL/kg bolus given over 10 minutes followed by a constant rate infusion of 0.25 mL/kg/min for 2 hours. The cat developed gross lipemia that persisted at least 48 hours after the single dose of IVLT. Changes consistent with corneal lipidosis were observed and resolved within 1 week after IVLT.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report documenting the complications of persistent gross lipemia and suspected corneal lipidosis in a cat following IVLT. This report underscores the off-label, experimental nature of IVLT as a treatment for intoxication in cats.

Specific impedance of canine blood

The specific impedance of canine erythrocytes suspended in plasma was measured in the frequency range from 5 kHz to 1 MHz in samples from three animals in the hematocrit range from zero to packed cells at a temperature of 39 degrees C; measurements were made with a conductivity cell using four electrodes and a current density of 21 microA/cm2. With the use of impedance spectroscopy, data were fitted to an equivalent circuit model; model parameters in turn were fitted as functions of hematocrit. The resultant model can be used to predict specific impedance (real and reactive components) as a function of hematocrit and frequency over a frequency range from 5 kHz to 1 MHz and a hematocrit range from 0 to 80. Over a normal range of hematocrits and at frequencies less than 100 kHz, the current is almost exclusively confined to the plasma, and the specific impedance is nearly equal to the real component; however, at higher frequencies, the complex nature of specific impedance becomes important.