Monique N. Mayer

Complications associated with the use of vascular access ports in dogs receiving external beam radiation therapy

OBJECTIVE To assess the perioperative and postoperative complications associated with use of vascular access ports (VAPs) in the jugular and lateral saphenous veins of dogs requiring frequent anesthetic episodes for radiation therapy. DESIGN Cohort study. ANIMALS 40 dogs referred to a veterinary teaching hospital. PROCEDURES VAPs were used in 23 dogs, and intravenous catheters inserted in a peripheral vein were used in 17 dogs. The frequency of perioperative and postoperative complications associated with VAP use and the frequency of infection associated with intravenous catheter use were recorded. Results of bacterial culture of VAP tips and amount of time required for VAP placement and removal and for anesthetic induction were also recorded. RESULTS VAP-associated perioperative complications included malposition of the catheter tip in 4 of 23 (17.4%) dogs. The VAP-associated postoperative complications included seroma formation in 7 (30.4%) dogs, breakage of port-anchoring sutures in 3 (13.0%) dogs, suspected fatal catheter-related septicemia in 1 (4.3%) dog, and temporary partial withdrawal occlusion in 18 of 255 (7.1%) anesthetic episodes. CONCLUSIONS AND CLINICAL RELEVANCE Placement of VAPs provided ready access in dogs receiving radiation therapy. Most complications were minor and self-limiting; however, a low risk of serious complications existed. Use of fluoroscopy to assess position of the catheter tip is recommended to decrease the risk of malposition. Immediate removal of a VAP is recommended when clinical signs of infection develop. Removal of a VAP at the completion of radiation therapy should be performed unless the benefit of continued vascular access outweighs the risks.

Use of a real-time three-dimensional motion tracking system for measurement of intrafractional motion of the thoracic wall in dogs

OBJECTIVE To measure respiratory motion of the thoracic wall region in dogs using a real-time motion tracking system and compare the amount of respiratory motion between dogs positioned with and without a vacuum-formable cushion. ANIMALS 8 healthy adult mixed-breed dogs (median weight, 23 kg). PROCEDURES Dogs were anesthetized and positioned in sternal and dorsal recumbency with and without a vacuum-formable cushion. Three-dimensional movement of anatomic landmarks was measured with a real-time motion capture system that tracked the locations of infrared light-emitting diodes attached externally to the dorsal or ventral and lateral aspects of the thoracic wall. RESULTS Dogs positioned in sternal recumbency had significantly less cranial-to-caudal and left-to-right respiratory motion at the lateral aspect of the thoracic wall, compared with dogs positioned in dorsal recumbency, whether or not a cushion was used. For dogs treated in sternal recumbency, use of a cushion significantly increased the peak displacement vector (overall movement in 3-D space) for 3 of 4 marker locations on the dorsal thoracic wall. As respiratory rate increased, respiratory motion at the lateral and ventral aspects of the thoracic wall decreased when data for all dogs in dorsal recumbency were evaluated together. CONCLUSIONS AND CLINICAL RELEVANCE Associations between respiratory rate and respiratory motion suggested that the use of rapid, shallow ventilation may be beneficial for dogs undergoing highly conformal radiation treatment. These results provide a basis for further research on respiratory motion in anesthetized dogs.

Sonographic Evaluation of Liver Hemodynamic Indices in Overweight and Obese Dogs

Background Hepatic circulatory disturbances have been associated with obesity and fatty liver in humans. In the veterinary literature, however, there is limited information regarding the effects of different body condition scores (BCS) on liver hemodynamic indices in dogs. Objectives To investigate the influence of BCS on liver hemodynamic indices. Animals Fifty‐three client‐owned dogs of various breeds were included. Methods Prospective observational study. Dogs were divided into 3 BCS groups using a 5‐point scale: G1 – 12 ideal dogs, G2 – 21 overweight dogs, G3 – 20 obese dogs. Mean portal velocity (MPV), portal blood flow volume (PBFV), portal congestion index (PCI), hepatic artery resistivity index (HARI), and hepatic vein (HV) spectral wave were obtained by pulsed Doppler sonography. Alkaline phosphatase (ALP), gamma‐glutamyl transferase (GGT), and alanine aminotransferase (ALT) activities were determined. Liver enzymes activities and liver hemodynamic indices were compared among groups. Results Obese dogs had lower MPV, higher percentage of abnormal hepatic vein spectral wave and higher median ALP activity than did ideal dogs (P < 0.05). Overweight and obese dogs had lower PBFV than ideal dogs (P < 0.01). Overweight dogs had higher median GGT activity than ideal dogs (P < 0.05). No difference was observed for PCI, HARI and median ALT activity among the groups. Conclusions and Clinical Importance Obesity was associated with changes in portal vein indices and in HV spectral wave. These changes were accompanied by significant differences in some liver enzymes activities and could be a sign of early liver disease.