Trial of Inspiratory Muscle Rest and Exercise in Chronic Obstructive Lung Disease
Condition: Lung Diseases; Lung Diseases, Obstructive; Chronic Obstructive Pulmonary Disease
MeSH terms: Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
Study type: Interventional
Phase: Phase 3

Summary: 
      To test the effectiveness of ventilatory muscle rest (VMR) using home negative pressure
      ventilation (NPV) in improving exercise performance, alleviating dyspnea, and improving the
      quality of life in patients with severe chronic obstructive lung disease.
    

Detailed description: 
      BACKGROUND:

      The potential importance of respiratory, chiefly inspiratory-muscle, fatigue had only
      recently been appreciated. If inspiratory muscles fail, so does ventilation and tissue
      respiration. There are theoretical reasons to postulate inspiratory muscle failure in chronic
      obstructive pulmonary disease, and suggestions that it may occur in an acute form with
      exacerbations and in a chronic form during 'stability'. There are two therapeutic strategies
      available for prevention and treatment of inspiratory muscle fatigue: training inspiratory
      muscles to increase their efficiency and resting fatigued muscles. The former should work if
      chronic fatigue is not present, and the latter should allow recovery from chronic fatigue, so
      the two approaches are not necessarily mutually exclusive. This proposal was originally
      designed to test the efficacy of each of these therapies alone and also in combination;
      however, given the experience of a pretrial period, these goals were scaled back. Since there
      was reason to believe that VMR may be more effective than IMT, the trial focused on VMR and
      sham VMR only.

      Ventilatory muscle rest was applied using a negative pressure ventilation suit sealed at the
      patient's hips, arms, and neck. A widebore tube connected to a fitting in the suit above the
      grid on the chest and upper abdomen transmitted negative pressure to the chest wall from the
      pump, thereby inflating the lungs.

      The evidence for chronic inspiratory muscle fatigue in patients with COLD resided largely in
      several relatively poorly controlled studies indicating that nocturnal artificial
      ventilation, which presumably rested the inspiratory muscles, produced improvement in daytime
      function and blood gases. The trial produced some badly needed data on both the occurrence of
      inspiratory muscle fatigue in COLD patients and its treatment with VMR.

      DESIGN NARRATIVE:

      Randomized, blinded. A total of 1,231 patients in the metropolitan Montreal area were
      screened. Of these, 348 were recruited to enter a four week stabilization period, and 184
      were subsequently randomized to either active or sham negative pressure ventilation (NPV). A
      five day in-hospital period was used to train patients in ventilator use and obtain baseline
      measures of exercise capacity, lung function, respiratory symptoms, and quality of life.
      Randomization was stratified on the basis of whether or not the patient had been receiving
      oxygen at home. Home ventilation treatment took place during a following 12-week period.
      Respirator use was recorded from patient logs and from concealed meters installed in the
      units. Patients received four home visits by physiotherapists during the 12-week period and
      returned to the hospital for follow-up at four and twelve weeks post-discharge for
      reassessment. The principal outcome measure was the distance in meters walked in six minutes.
      Secondary outcome measures were cycle exercise endurance time, severity of dyspnea, quality
      of life, arterial blood gas tensions, and respiratory muscle strength.
    

Intervention name(s): ventilators, negative pressure
Intervention type(s): Device
Allocation: Randomized
Primary purpose: Treatment