National Center for Trauma Medicine, Trauma Medicine Center, Ministry of Education Key Laboratory of Trauma and Neuroregeneration, Peking University People's Hospital, Beijing, China.
Orthop Surg. 2023 Apr;15(4):1144-1152. doi: 10.1111/os.13630. Epub 2023 Mar 1.
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.
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.
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.
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.
比较不同程度的胸腔容积减少对呼吸功能的影响，评估胸腔容积减少大鼠的耐受性，并评估胸腔容积作为评估肋骨骨折严重程度的指标的可行性。
24 只 10 周龄雌性 Sprague-Dawley（SD）大鼠随机分为四组（每组 6 只），根据双侧肋骨骨折移位程度（2、4、6 和 8mm）进行分组。通过全身气压体积描记法在术前和术后连续 14 天测量大鼠的呼吸功能（潮气量、吸气时间、呼气时间、呼吸频率、分钟通气量、吸气峰流量）。分析各组呼吸功能参数。在术前和术后 14 天进行胸部 CT 扫描，然后使用计算机软件重建胸部和肺部的三维结构，并测量其体积。我们计算了术后胸腔和肺部容积减少的百分比。
术后第 14 天，2、4、6 和 8mm 组的胸腔容积减少率分别为 5.20%、9.01%、16.67%和 20.74%。8mm 组的肺容积明显减少。与术前相比，每组术后的潮气量均较低。2mm 组的潮气量在术后逐渐恢复，术后第 14 天恢复至正常水平（1.54±0.07mL）。4、6 和 8mm 组的潮气量在术后逐渐恢复，但在第 14 天未恢复至基线水平。特别是 8mm 组在 14 天内的潮气量明显低于其他组（1.23±0.12mL，p<0.05）。每组术后 14 天的吸气和呼气时间、吸气和呼气峰流量、呼吸频率和分钟通气量均无明显变化。
移位性肋骨骨折导致胸腔塌陷和胸腔容积减少，可影响大鼠的潮气量。胸腔容积减少越大，早期潮气量减少越明显。胸腔容积可作为评估多发性肋骨骨折严重程度的客观参数。早期手术恢复胸腔容积可能改善早期呼吸功能。胸腔容积减少会影响呼吸功能，但可以在长期内得到代偿和恢复。
