吸氣肌訓練對慢性阻塞性肺病患者急性惡化後之療效探討

Abstract

背景與目的：慢性阻塞性肺病急性惡化（acute exacerbation of chronic obstructive pulmonary disease, AECOPD）後患者常出現吸氣肌肌力降低、功能性運動受限及生活品質變差的現象。過去研究發現急性惡化後介入肺復原計畫可改善功能性運動能力及生活品質。此外，吸氣肌訓練可增加臨床狀況穩定之慢性阻塞性肺病患者的吸氣肌肌力和耐力，但在肺復原計畫中加入吸氣肌訓練是否可以改善慢性阻塞性肺病急性惡化患者的吸氣肌功能之相關研究尚缺。本研究目的為探討肺復原外加吸氣肌訓練對慢性阻塞性肺病急性惡化患者其吸氣肌功能、功能性運動能力與生活品質之效益。研究方法：受試者為經胸腔內科醫師確診為急性惡化且最大吸氣壓（maximal inspiratory pressure, PImax）小於80公分水柱（cmH2O）之慢性阻塞性肺病患者，隨機分配至實驗組（肺復原合併吸氣肌訓練）或控制組（肺復原合併假性吸氣肌訓練）進行八週之介入。基線（T0）測量包括：臨床表徵等基本資料之收集、肺功能測試、最大吸氣壓測試、六分鐘行走測試、生活品質問卷、及吸氣肌（橫膈肌與胸鎖乳突肌）負荷表現測試。吸氣肌表面肌電圖評估在最大吸氣壓測試及執行吸氣負荷任務時同步進行。八週肺復原之介入包含有氧運動訓練、肌力訓練、及相關衛教。實驗組在肺復原進行時外加吸氣肌訓練。吸氣肌訓練劑量為：強度30%之PImax、15次/回、6回/天、7天/週，為期8週，並依每週測得之PImax進行強度調整。在介入第四週（T1）、完成介入後（T2）與介入完成後一個月後（T3）重複上述所有測試來進行成效評估。表面肌電圖分析參數包括以時域分析之方均根值（root mean square, RMS）與頻域分析之中位頻率（median frequency, MF），分別用來評估吸氣負荷任務下的吸氣肌肌電活化度與中位頻率之變化。統計以廣義估計方程式（generalized estimating equation, GEE）檢定不同時間點在組間與組內各項參數之差異，顯著統計意義有效水平標準p訂為0.05。研究結果：16位（每組8位）平均最大吸氣壓為65.3公分水柱之慢性阻塞性肺病急性惡化患者參與本研究。實驗組在吸氣肌肌力、橫膈肌肌電活化度、六分鐘行走距離、聖喬治呼吸問卷（St. George’s respiratory questionnaire, SGRQ）總分、與慢性阻塞性肺病評估測試（COPD assessment test, CAT）於T1、T2、以及T3均具有顯著且持續的改善（所有p<0.05）。經過八週介入後，與控制組相比，實驗組具有較佳的吸氣肌肌力（104.3±16.9 vs. 72.3±12.8公分水柱）與較低的橫膈肌肌電活化度（吸氣負荷任務測試：32.2±9.1 vs. 53.7±14.8%）（所有p<0.001）。此外，與控制組相比，實驗組於八週介入前後在六分鐘行走測驗（+66.3 vs. +32.5公尺）與聖喬治呼吸問卷總分（-22.6 vs. -13.5）皆呈現較大進步量（所有p<0.05）。結論：相較於沒有外加吸氣肌訓練，在肺復原計劃加入吸氣肌訓練，慢性阻塞性肺病急性惡化伴隨吸氣肌無力患者之吸氣肌功能、功能性運動表現與生活品質展現較顯著的進步。此訓練方式可使慢性阻塞性肺病急性惡化的整合照護更臻周全。

Background and purpose: After experiencing an acute exacerbation of chronic obstructive pulmonary disease (AECOPD), patients often have decreased inspiratory muscle strength, reduced exercise capacity, and impaired quality of life (QoL). Previous studies have shown that pulmonary rehabilitation (PR) initiated after exacerbations could improve exercise capacity and QoL. It has also been demonstrated that inspiratory muscle training (IMT) can increase inspiratory muscle strength and endurance in patients with stable COPD. However, the impact of adding IMT to PR on inspiratory muscle function in patients with AECOPD has not yet been fully explored. This study aimed to evaluate the effects of IMT in addition to PR on inspiratory muscle function, functional exercise capacity, and QoL in patients with AECOPD. Methods: Patients diagnosed with AECOPD and a maximal inspiratory pressure (PImax) < 80 cmH2O were recruited and randomized into the experimental (PR+IMT) or the control (PR+sham IMT) group for an 8-week intervention. Baseline assessments (T0) included the collection of clinical data, pulmonary function test, maximal inspiratory pressure test, a six-minute walk test, quality of life (QoL) questionnaires, and inspiratory muscle (diaphragm and sternocleidomastoid) response to threshold loaded breathing test. Surface electromyography (EMG) was used during maximal inspiratory pressure and threshold loaded breathing testing to assess inspiratory muscle activation. All subjects underwent an 8-week structural PR, which included aerobic exercise training, resistance training, and education. Subjects in the experimental group received additional IMT with an intensity of 30% PImax, 15 times/set, 6 sets/day, 7 days/week, for a total of 8 weeks. At 4 weeks into the intervention (T1), after the intervention was completed (T2), and 1 month after the completion of the intervention (T3), subjects underwent all of the same test that were administered at baseline (T0). The root mean square (RMS) value and median frequency (MF) were calculated from surface EMG signals, and the inspiratory muscle activation during threshold loaded breathing test and changes of MF were analyzed. The generalized estimating equation (GEE) model was used to detect the differences in variables between and within groups. The statistical significance level was set at 0.05. Results: A total of 16 patients (n=8 per group) diagnosed with AECOPD with a mean PImax of 65.3 cmH2O participated in this study. The experimental group showed sustained and significant improvements in inspiratory muscle strength, diaphragm activation, six-minute walk distance (6MWD), St. George’s respiratory questionnaire (SGRQ) total scores, and COPD assessment test (CAT) scores at T1, T2, and T3 (all p<0.05). When compared to the control group, the experimental group had greater inspiratory muscle strength (104.3±16.9 vs. 72.3±12.8 cmH2O), and less diaphragm activation (threshold loaded breathing test: 32.2±9.1 vs. 53.7±14.8%) at T2 (both p<0.001). Compared to the control group, the experimental group showed more improvements in 6MWD (+66.3 vs. +32.5 m) and SGRQ total scores (-22.6 vs. -13.5) from T0 to T2 (both p<0.05). Conclusion: The combination of IMT and PR, compared to PR alone, provided more improvements in inspiratory muscle function, functional exercise capacity, and QoL in patients with AECOPD and inspiratory muscle weakness. The combination program might improve the overall management of AECOPD.