Comparison of CPAP and oxygen therapy for treatment of postoperative hypoxaemia in dogs.

OBJECTIVE: To compare 5 cmH2 O of continuous positive airway pressure with oxygen therapy in dogs recovering from general anaesthesia with low SpO2 values. continuous positive airway pressure is more effective than oxygen therapy in restoring normoxaemia (SpO2 ≥95%). MATERIALS AND METHODS: Prospectively, dogs recovering from anaesthesia, with SpO2 <95% after extubation (T0), were randomised and treated with continuous positive airway pressure (FiO2 0.21) or oxygen (O2 ; FiO2 0.35-0.40) therapy. Dogs were monitored with SpO2 every 15 minutes for 1 hour (T15, T30, T45, T60). Data from normoxaemic dogs (SpO2 >95%) were used as control (CTR). RESULTS: Of the 42 dogs enrolled, 34 completed the study. Eleven dogs were treated with O2 , 10 with continuous positive airway pressure and 13 were CTR. The SpO2 values at T0 were similar in the continuous positive airway pressure and O2 groups and were lower than in the CTR group. At T15, T30, T45 and T60, the SpO2 values in the continuous positive airway pressure group were higher than at T0; these were similar to those of the CTR group at the same time-points. In the O2 group, SpO2 values were significantly higher at T45 and T60 than at T0; 45.5% of dogs became normoxaemic at T45 and the remaining dogs became normoxaemic at T60. The average time to reach normoxaemia in the O2 group (53.1±7.3 minutes) was longer than in the continuous positive airway pressure group (15.0±0.0 minutes). CLINICAL SIGNIFICANCE: In dogs recovering from general anaesthesia with pulmonary gas exchange impairment, normoxaemia is restored more effectively and rapidly by using continuous positive airway pressure than by oxygen therapy.

Comparison of three novel biphasic scaffolds for one-stage treatment of osteochondral defects in a sheep model.

In the last years, several tissue engineering techniques have been applied to develop different kinds of osteochondral substitutes to overcome the scarce reparative properties of this tissue. The aim of this study was to generate and compare three biphasic scaffolds in an osteochondral lesion in a large-animal model. A critical osteochondral defect was generated in the medial femoral condyle of 18 skeletally mature sheep. Three defects were left untreated, the remaining lesions were divided into three groups: 5 lesions were treated with a biphasic scaffold made of collagen type I and small cylinders of Magnesium Hydroxyapatite; 5 lesions were treated with a biphasic substituted formed by collagen type I and Wollastonite, 5 lesions were treated with a scaffold made of collagen type I and small cylinders of Wollastonite/Hydroxyapatite. Animals were sacrificed after 3 months and samples were analyzed by CT and MRI, macroscopic evaluation and histology. Our study demonstrated that one of these novel biphasic scaffolds possesses the potential for being applied for one-stage procedures for osteochondral defects.