The accessory lung lobe in thoracic disease: a case series and anatomical review.

Diseases of the accessory lung lobe (AccLL) are often overlooked in dogs and cats, perhaps because of its recessed location. Diseases of this lobe also can mimic diseases of the diaphragm or structures comprising the caudal mediastinum. Normal anatomy of the AccLL and the diagnostic tools used today will be reviewed to help differentiate disease of adjacent organs. Four cases will also be described to illustrate disease presentation and radiographic findings affecting this lobe.

Evaluation of the bone injection gun as a method for intraosseous cannula placement for fluid therapy in adult dogs.

OBJECTIVE: To evaluate the Bone Injection Gun (BIG) for placement of intraosseous cannulas through impact penetration and compare it with a standard Jamshidi bone marrow needle (JBMN) and to compare fluid delivery dynamics through each device. STUDY DESIGN: Randomized in vivo study. ANIMALS: Forty-eight mature dogs. METHODS: During surgical laboratories, dogs were randomly assigned to 2 groups (n = 24), and intraosseous access in the proximal tibial metaphysis was obtained using a BIG or JBMN. Variables measured during placement included insertion success, time required for placement, and alterations in respiratory rate (RR), heart rate (HR), and systolic blood pressure. After placement, maintenance fluids were administered to 6 dogs from each group, and fluids were administered under pressure to 6 dogs from each group to compare rates of delivery through each device. After euthanasia, the tibiae were harvested to evaluate and compare the morphologic consequences of needle and cannula placement. RESULTS: Successful placement occurred in 20 (83%) dogs for the BIG and 23 (96%) dogs for the JBMN, which was not significantly different (P =.3475). Time required for placement was significantly less (P =.0024) for the BIG (mean, 22.4 +/- 8.2 seconds) compared with the JBMN (mean, 42.0 +/- 28.1 seconds). Significant increases in RR occurred in both groups and in the HR for the BIG group, but significant differences were not noted between groups. Mean rate of pressurized fluid administration was similar for both groups. Two distinct patterns of cortical bone damage occurred, but the clinical significance of this observation is uncertain. CONCLUSIONS: The BIG provides more rapid access to the intraosseous space for fluid administration than the JBMN. CLINICAL RELEVANCE: The BIG is an effective alternative for obtaining rapid access to the intraosseous space for emergency fluid and drug administration.

Clinical management of flail chest in dogs and cats: a retrospective study of 24 cases (1989-1999).

Cases of flail chest injury for 24 client-owned companion animals following various traumas were evaluated. Concurrently sustained injuries, initial emergency treatments, and definitive treatment and outcome for regimens that utilize stabilization of the flail segment were compared with cases treated with no stabilization. Flail chest was confirmed in 24 animals: 21 dogs and three cats. There was an even division (12 each) of right and left flail segments. The median number of ribs involved was three (range, two to seven). Flail segment stabilization was performed in nine, and 15 were treated with no stabilization. Statistical analysis using multiple data permutations evaluating all combinations failed to reveal a significant difference in outcome between stabilized and unstabilized cases.

Postoperative rupture of an aortic aneurysmal dilation associated with a patent ductus arteriosus in a dog.

OBJECTIVE: To describe an unusual case of fatal aortic aneurysm rupture after standard ligation of a left-to-right shunting patent ductus arteriosus (PDA) and review the literature concerning the causes of aneurysm and applicable medical physics of blood flow that may contribute to mural failure. STUDY DESIGN: Clinical case report. SAMPLE POPULATION: An 11-month-old female Brittany spaniel. RESULTS: A PDA was diagnosed in the dog after referral for a grade IV/IV cardiac murmur. Diagnostic tests performed included a minimum database, thoracic radiography, and echocardiography. Conventional surgical ligation of the PDA was performed. The postoperative recovery from anesthesia was uneventful. Approximately 5 hours after surgery, the dog vocalized once and collapsed. All resuscitative efforts failed. Necropsy showed a large, spiral rupture of the cranial and dorsal wall of the aorta that extended from the left subclavian artery to 2 cm distal to the PDA-aorta junction. No evidence of intramural, perianeurysmal hemorrhage or inflammation was noted. Histopathologic examination of the ruptured aneurysm showed that the wall lacked a defined tunica intima and endothelial cell layer. A distinct separation of the thinned tunica media parallel to the elastic fibers was noted. CONCLUSIONS AND CLINICAL RELEVANCE: Dilatation of the aorta near the area of a PDA is one of the recognized abnormalities associated with the condition. Aneurysmal dilatation results from and contributes to abnormal blood flow dynamics and increased aortic wall tension, which promotes expansion. Although an unusual and previously unreported sequela, rupture of the aneurysm should be considered a possible complication when ligation of a PDA with a conspicuous aortic aneurysmal dilation is performed.

Thoracoscopic visualization and ligation of the thoracic duct in dogs.

OBJECTIVE: To develop a technique for thoracoscopic visualization and ligation of the thoracic duct in dogs. STUDY DESIGN: In vivo experimental study. ANIMALS: Five mature, healthy dogs. METHODS: Dogs were normal based on physical examination, negative occult heartworm test, normal complete blood count and biochemical profile, and normal thoracic radiographs. The dogs were anesthetized, and a ventral midline laparotomy was performed for catheterization of a mesenteric lymphatic. Lymphangiography was performed to determine thoracic duct anatomy. Thoracoscopy was performed in the caudal, right hemithorax after single lung intubation or bronchial blockade. At least two 10-mm clips were placed across the thoracic duct in each dog. Lymphangiography was repeated to assess duct ligation. If complete duct occlusion was not achieved, thoracoscopy was repeated for additional clip placement. After surgery the dogs were euthanatized, and necropsies were performed. RESULTS: Lymphangiography showed that multiple branches of the thoracic duct were present in every dog; bilateral thoracic duct branches were most common. Thoracoscopic identification and ligation of the thoracic duct was successful in all five dogs. Two dogs required a second thoracoscopic procedure to completely occlude flow of contrast through the thoracic duct. Surgery time for thoracoscopy averaged 59 plus minus 9.6 minutes. Retroperitoneal contrast accumulation after thoracic duct ligation occurred in two dogs. One dog required bilateral pulmonary ventilation. CONCLUSION: Thoracoscopy can be used to visualize the thoracic duct for ligation in normal dogs. CLINICAL RELEVANCE: Thoracoscopic ligation of the thoracic duct may be a therapeutic option for management of chylothorax in dogs.