Department of Physical Therapy, University of Florida, 1600 South West Archer Road, PO Box 100154, Gainesville, FL 32610, USA.
Crit Care. 2011;15(2):R84. doi: 10.1186/cc10081. Epub 2011 Mar 7.
Most patients are readily liberated from mechanical ventilation (MV) support, however, 10% - 15% of patients experience failure to wean (FTW). FTW patients account for approximately 40% of all MV days and have significantly worse clinical outcomes. MV induced inspiratory muscle weakness has been implicated as a contributor to FTW and recent work has documented inspiratory muscle weakness in humans supported with MV.
We conducted a single center, single-blind, randomized controlled trial to test whether inspiratory muscle strength training (IMST) would improve weaning outcome in FTW patients. Of 129 patients evaluated for participation, 69 were enrolled and studied. 35 subjects were randomly assigned to the IMST condition and 34 to the SHAM treatment. IMST was performed with a threshold inspiratory device, set at the highest pressure tolerated and progressed daily. SHAM training provided a constant, low inspiratory pressure load. Subjects completed 4 sets of 6-10 training breaths, 5 days per week. Subjects also performed progressively longer breathing trials daily per protocol. The weaning criterion was 72 consecutive hours without MV support. Subjects were blinded to group assignment, and were treated until weaned or 28 days.
Groups were comparable on demographic and clinical variables at baseline. The IMST and SHAM groups respectively received 41.9 ± 25.5 vs. 47.3 ± 33.0 days of MV support prior to starting intervention, P = 0.36. The IMST and SHAM groups participated in 9.7 ± 4.0 and 11.0 ± 4.8 training sessions, respectively, P = 0.09. The SHAM group's pre to post-training maximal inspiratory pressure (MIP) change was not significant (-43.5 ± 17.8 vs. -45.1 ± 19.5 cm H2O, P = 0.39), while the IMST group's MIP increased (-44.4 ± 18.4 vs. -54.1 ± 17.8 cm H2O, P < 0.0001). There were no adverse events observed during IMST or SHAM treatments. Twenty-five of 35 IMST subjects weaned (71%, 95% confidence interval (CI) = 55% to 84%), while 16 of 34 (47%, 95% CI = 31% to 63%) SHAM subjects weaned, P = .039. The number of patients needed to be treated for effect was 4 (95% CI = 2 to 80).
An IMST program can lead to increased MIP and improved weaning outcome in FTW patients compared to SHAM treatment.
ClinicalTrials.gov: NCT00419458.
大多数患者可顺利脱离机械通气（MV）支持，但仍有 10%-15%的患者存在撤机失败（FTW）。FTW 患者约占所有 MV 天数的 40%，且临床预后显著更差。MV 导致的吸气肌无力被认为是 FTW 的一个促成因素，最近的研究记录了接受 MV 支持的人类存在吸气肌无力。
我们开展了一项单中心、单盲、随机对照试验，以检验吸气肌力量训练（IMST）是否能改善 FTW 患者的撤机结局。在评估参与的 129 名患者中，有 69 名患者入组并进行了研究。35 名患者被随机分配至 IMST 组，34 名患者分配至 sham 治疗组。IMST 使用吸气阈设备进行，设置为能耐受的最高压力，并每天逐渐增加。 sham 训练提供恒定的低吸气压力负荷。患者每周进行 5 天，每天完成 4 组 6-10 次训练呼吸。根据方案，患者每天还进行更长时间的呼吸试验。撤机标准为无 MV 支持的连续 72 小时。患者对分组情况设盲，并进行治疗直至撤机或 28 天。
两组患者在基线时的人口统计学和临床变量方面具有可比性。IMST 组和 sham 组分别在开始干预前接受了 41.9±25.5 天和 47.3±33.0 天的 MV 支持，P=0.36。IMST 组和 sham 组分别参加了 9.7±4.0 次和 11.0±4.8 次训练，P=0.09。 sham 组的最大吸气压力（MIP）从训练前到训练后的变化不显著（-43.5±17.8 比-45.1±19.5 cm H2O，P=0.39），而 IMST 组的 MIP 增加（-44.4±18.4 比-54.1±17.8 cm H2O，P<0.0001）。在 IMST 或 sham 治疗期间未观察到不良事件。35 名 IMST 患者中有 25 名（71%，95%置信区间（CI）=55%至 84%）撤机，34 名 sham 患者中有 16 名（47%，95% CI=31%至 63%）撤机，P=0.039。为了获得效果，需要治疗的患者人数为 4 人（95%CI=2 至 80）。
与 sham 治疗相比，IMST 方案可导致 FTW 患者的 MIP 增加和撤机结局改善。
ClinicalTrials.gov：NCT00419458。
