Lands L C, Smountas A A, Mesiano G, Brosseau L, Shennib H, Charbonneau M, Gauthier R
Département de Chirurgie Cardiothoracique, L'Hôpital Notre Dame-Université de Montréal, Quebec.
J Heart Lung Transplant. 1999 Feb;18(2):113-20. doi: 10.1016/s1053-2498(98)00027-8.
There have been many suggestions that diminished exercise capacity in patients that have undergone lung transplantation is due, in part, to peripheral muscle dysfunction, brought on by either detraining or immunosuppressive therapy. There is limited data quantifying skeletal muscle function in this population, especially in those more than 18 months post-procedure. The present study sought to quantitate skeletal muscle function and cardiopulmonary responses to graded exercise in 19 lung transplant recipients, 15 of which were mostly more than 18 months post-procedure.
Ten single- (SLT) and 9 double-lung transplantation (DLT) underwent anthropometric measures and performed expiratory spirometry, whole body plethysmography to assess lung volumes, static maximal mouth pressures to assess respiratory muscle strength, progressive exercise testing on a cycle ergometer (with cardiac output measurements being performed every second workload) and isokinetic cycling to assess peripheral muscle power and work capacity.
The DLT group was younger than the SLT group (23.0 [21.0-32.0] vs 47.5 [43.0-55.0] median [interquartile range], p < .05) with no differences in height, weight, or BMI. Despite the DLT group having significantly better spirometric values (FEV1: 86% vs 56.5% median) and less airtrapping (RV/TLC: 30% vs 53.5%), both groups were equally limited in exercise capacity (Wmax)(38.0 percent predicted [30.0-65.0] vs 37.5 percent predicted [30.0-44.0], SLT vs DLT), leg power (76.1 percent predicted [53.8-81.4] vs 69.0 percent predicted [58.3-76.0]) and leg work capacity (63.3 percent predicted [34.7-66.8] vs 38.4 percent predicted [27.5-57.3]). This lack of difference in performance persisted when the analysis was limited to those more than 18 months post-procedure. Respiratory muscle strength was also not different for the two groups, and was within normal limits. Wmax was best correlated with leg work capacity (r = .84), but also with leg power, RV/TLC, FEV1 (r = .49, -.52, .58). When normalized for age, height, and sex, percent predicted Wmax only correlated with percent predicted leg work capacity (r = .58). Cardiac output was appropriate for the work performed.
We conclude that peripheral skeletal muscle work capacity is reduced following lung transplantation and mostly responsible for the limitation of exercise performance. While the causes of muscular dysfunction have yet to be clarified, the preservation of respiratory muscle strength with the concomitant reduction in leg power and work capacity suggests that most of the muscular dysfunction post-transplantation is attributable to detraining.
许多研究表明，肺移植患者运动能力下降部分归因于废用训练或免疫抑制治疗导致的外周肌肉功能障碍。目前量化该人群骨骼肌功能的数据有限，尤其是术后超过18个月的患者。本研究旨在对19例肺移植受者的骨骼肌功能及分级运动时的心肺反应进行定量分析，其中15例术后时间大多超过18个月。
10例接受单肺移植（SLT）和9例接受双肺移植（DLT）的患者进行人体测量，并进行呼气肺活量测定、全身体积描记法以评估肺容量、静态最大口腔压力以评估呼吸肌力量、在功率自行车上进行渐进性运动测试（每两个工作负荷测量一次心输出量）以及等速骑行以评估外周肌肉力量和工作能力。
DLT组患者比SLT组患者年轻（中位数[四分位间距]：23.0[21.0 - 32.0]岁 vs 47.5[43.0 - 55.0]岁，p < 0.05），身高、体重或体重指数无差异。尽管DLT组患者的肺活量测定值明显更好（第一秒用力呼气容积：中位数86% vs 56.5%）且气体潴留更少（残气量/肺总量：30% vs 53.5%），但两组患者的运动能力（最大摄氧量）均同样受限（预测值百分比：SLT组为38.0%[30.0 - 65.0]，DLT组为37.5%[30.0 - 44.0]）、腿部力量（预测值百分比：76.1%[53.8 - 81.4] vs 69.0%[58.3 - 76.0]）和腿部工作能力（预测值百分比：63.3%[34.7 - 66.8] vs 38.4%[27.5 - 57.3]）。当分析仅限于术后超过18个月的患者时，这种表现上的差异依然存在。两组患者的呼吸肌力量也无差异，且均在正常范围内。最大摄氧量与腿部工作能力相关性最好（r = 0.84），但也与腿部力量、残气量/肺总量、第一秒用力呼气容积相关（r = 0.49、 - 0.52、0.58）。经年龄、身高和性别标准化后，预测最大摄氧量百分比仅与预测腿部工作能力百分比相关（r = 0.58）。心输出量与所做的功相匹配。
我们得出结论，肺移植后外周骨骼肌工作能力下降，这是运动表现受限的主要原因。虽然肌肉功能障碍的原因尚待阐明，但呼吸肌力量得以保留，同时腿部力量和工作能力下降，这表明移植后大部分肌肉功能障碍归因于废用训练。
