目的:比较呼吸功能对不同程度胸廓容积减少的影响,并评估胸廓容积减少的大鼠的耐受性,并评估胸廓容积作为衡量肋骨骨折严重程度的可行性。
方法:将24只10周龄雌性Sprague-Dawley(SD)大鼠根据双侧肋骨骨折的移位程度(2、4、6、8mm)随机分为4组(每组6只)。大鼠的呼吸功能(潮气量,灵感时间,到期时间,呼吸率,分钟音量,峰值吸气流量)在手术前后连续14天通过全身气压体积描记术测量。分析各组呼吸功能参数。术前和术后14天进行胸部CT扫描,之后,我们重建了胸部和肺部的三维结构,并通过计算机软件测量了它们的体积。我们计算了术后胸部和肺部减容的百分比。
结果:手术后第14天,2,4,6和8mm组的胸腔容积率下降为5.20%,9.01%,16.67%,和20.74%,分别。8mm组显示肺体积显著减小。各组术后潮气量均低于术前基线值。2mm组术后潮气量逐渐恢复,术后第14天恢复至正常水平(1.54±0.07mL)。术后4、6、8mm组潮气量逐渐恢复,但在第14天没有恢复到基线水平.特别是,在14天内,8mm组的潮气量显着低于其他组(1.23±0.12mL,p<0.05)。吸气和呼气时间无明显变化,峰值吸气和呼气流量,呼吸频率,各组术后14天进行每分钟通气。
结论:肋骨骨折移位导致胸廓塌陷和胸廓容积减小,会影响大鼠潮气量。胸廓容积的减少越大,早期潮气量的减少越明显。胸廓容积可作为评价多发性肋骨骨折严重程度的客观参数。早期手术恢复胸廓容积可改善早期呼吸功能。胸廓容积减少会影响呼吸功能,可以长期补偿和恢复。
OBJECTIVE: To compare the effects of respiratory function on different degrees of reduced thoracic volume and evaluate the tolerance of rats with reduced thoracic volume, and to assess the feasibility of thoracic volume as a measure of the severity of rib fractures.
METHODS: A total of 24 10-week-old female Sprague-Dawley (SD) rats were randomly divided into four groups (n = 6 in each group) according to the displacement degree of bilateral rib fractures (2, 4, 6, and 8 mm). The respiratory function of the rats(Tidal volume, Inspiration time, Expiration time, Breath rate, Minute volume, Peak inspiration flow) measured via whole-body barometric plethysmography before and after operation for 14 consecutive days. Respiratory function parameters of each group were analyzed. Chest CT scans were performed before and 14 days after operation, after that we reconstructed three-dimensional of the thoracic and lung and measured their volumes by computer software. We calculated the percentage of thoracic and lung volume reduction after operation.
RESULTS: At the 14th day after the operation, the decline of thoracic volume rates of in the 2, 4, 6, and 8 mm groups were 5.20%, 9.01%, 16.67%, and 20.74%, respectively. The 8 mm group showed a significant reduction in lung volume. The postoperative tidal volumes were lower in each of the groups than the baseline values before the operation. The tidal volume of the 2 mm group gradually recovered after the operation and returned to a normal level (1.54 ± 0.07 mL) at 14th day after the operation. The tidal volume of the 4, 6, and 8 mm groups recovered gradually after the operation, but did not return to baseline level at the 14th day. In particular, the tidal volume of the 8 mm group was significantly lower than that of the other groups during the 14 days (1.23 ± 0.12 mL, p < 0.05). There were no significant changes in the inspiratory and expiratory times, peak inspiratory and expiratory flows, respiratory rate, and minute ventilation during the 14 days after the operation in each group.
CONCLUSIONS: Displaced rib fractures lead to thoracic collapse and reduced thoracic volume, which can affect tidal volume in rats. The greater the decrease of thoracic volume, the more obvious the decrease of early tidal volume. The thoracic volume can be used as an objective parameter to evaluate the severity of multiple rib fractures. Early operation to restore thoracic volume may improve early respiratory function. Decreased thoracic volume affected respiratory function and can be compensated and recovered in the long term.