Computed tomographic analysis of the effects of two inspired oxygen concentrations on pulmonary aeration in anesthetized and mechanically ventilated dogs

OBJECTIVE: To compare the effect of 2 concentrations of oxygen in inspired gas (fraction of inspired oxygen [FIO(2)] 1.0 or 0.4) on pulmonary aeration and gas exchange in dogs during inhalation anesthesia. ANIMALS: 20 healthy dogs. PROCEDURES: Following administration of acepromazine and morphine, anesthesia was induced in each dog with thiopental and maintained with isoflurane in 100% oxygen (100% group; n = 10) or a mixture of 40% oxygen and air (40% group; 10). Dogs were placed in dorsal recumbency and were mechanically ventilated. After surgery, spiral computed tomography (CT) of the thorax was performed and PaO(2), PaCO(2), and the alveolar-arterial oxygen tension difference (P([A-a])O(2)) were assessed. The lung CT images were analyzed, and the extent of hyperinflated (-1,000 to -901 Hounsfield units [HUs]), normally aerated (-900 to -501 HUs), poorly aerated (-500 to -101 HUs), or nonaerated (-100 to +100 HUs) areas was determined. RESULTS: Compared with the 100% oxygen group, the normally aerated lung area was significantly greater and the poorly aerated and nonaerated areas were significantly smaller in the 40% oxygen group. The time to CT (duration of surgery) was similar in both groups. Although PaCO(2) was similar in both groups, PaO(2) and P((A-a))O(2) were significantly higher in the 100% oxygen group. In both groups, pulmonary atelectasis developed preferentially in caudal lung fields. CONCLUSION AND CLINICAL RELEVANCE: In isoflurane-anesthetized dogs, mechanical ventilation with 40% oxygen appeared to maintain significantly better lung aeration and gas exchange than ventilation with 100% oxygen.     

Use of autologous bone marrow mononuclear cells and cultured bone marrow stromal cells in dogs with orthopaedic lesions

The aim of the study is to evaluate the clinical application in veterinary orthopedics of bone marrow mononuclear cells (BMMNCs) and cultured bone marrow stromal cells (cBMSCs) for the treatment of some orthopaedic lesions in the dog. The authors carried out a clinical study on 14 dogs of different breed, age and size with the following lesions: 1 bone cyst of the glenoid rime; 2 nonunion of the tibia; 3 nonunion of the femur; 2 lengthening of the radius; 1 large bone defect of the distal radius;1 nonunion with carpus valgus; 4 Legg-Calvé-Perthés disease. In 9 cases the BMMCNs were used in combination with a three dimensional resorbable osteogenic scaffold the chemical composition and size of which facilitates the ingrowth of bone. In these cases the BMMNCs were suspended in an adequate amount of fibrin glue and then distribuited uniformly on a Tricalcium-Phosphate (TCP) scaffold onto which were also added some drops of thrombin. In 1 case of nonunion of the tibia and in 3 cases of Legg-Calvè-Perthés (LCP) disease the cultured BMSCs were used instead because of the small size of the dogs and of the little amount of aspirated bone marrow. X-ray examinations were performed immediately after the surgery. Clinical, ultrasounds and X-ray examinations were performed after 20 days and then every month. Until now the treated dogs have shown very good clinical and X-ray results. One of the objectives of the study was to use the BMMNCs in clinical application in orthopaedic lesions in the dog. The advantages of using the cells immediately after the bone marrow is collected, are that the surgery can be performed the same day, the cells do not need to be expanded in vitro, they preserve their osteogenic potential to form bone and promote the proper integration of the implant with the bone and lastly, the technique is easier and the costs are lower.