Effects of the iron lung on respiratory function in chronic hypercapnic COPD patients

P. Goti, R. Duranti, A. Spinelli, M. Gorini, F. Gigliotti, G. Misuri, E. Rosi, I. Iandelli, G. Scano

Research output: Contribution to journalArticlepeer-review


Whether or not short-term negative pressure ventilation (NPV) improves respiratory function by decreasing the drive to the respiratory muscles in hypercapnic chronic obstructive pulmonary disease (COPD) patients remains to be defined. In six severely obstructed hypercapnic CORD patients (Group A) with grade IV dyspnoea (modified Medical Research Council (MRC) dyspnoea scale), we evaluated pulmonary volumes, arterial blood gases, the pattern of breathing (tidal volume (VT) and respiratory frequency (Rf)) and the neuromuscular respiratory drive (NMRD), before and immediately after a 7 day period with the iron lung (IL). NMRD was assessed by expressing mouth occlusion pressure (P0.1) recorded during quiet breathing as a percentage of maximal P0.1 recorded during exogenous CO2 stimulation (P0.1 max,CO2). A group of six hypercapnic, less dyspnoeic (grade II to III) COPD patients (Group B), with similar mechanical characteristics, and another less obstructed historically normocapnic control group (Group C) were also considered. Before IL, in Group A VT was lower than in C, and P0.1 (%P0.1 max,CO2) was greater than in Group B and C. After a 7 day period with IL, VT increased, Rf decreased, and arterial blood gases and dyspnoea grade improved; P0.1 (%P0.1 max,CO2) significantly decreased remaining, however, greater than in Group C. In Group A the time course of arterial carbon dioxide tension (Pa,CO2) and P0.1 (%P0.1 max,CO2) were significantly related to each other. These data seem to indicate that IL is effective in improving respiratory function and symptoms in chronic hypercapnic severely dyspnoeic COPD patients. The observation that these effects were associated with a decrease in NMRD reflects an improved efficiency of the respiratory system. After IL, respiratory function in Group A was similar or even better than that in Group B. This study also considers the possibility of putting severely dyspnoeic hypercapnic COPD patients into an IL trial before starting a traditional rehabilitation programme.

Original languageEnglish
Pages (from-to)427-432
Number of pages6
JournalMonaldi Archives for Chest Disease - Cardiac Series
Issue number6
Publication statusPublished - 1995


  • Chronic obstructive pulmonary disease
  • Iron lung
  • Mouth occlusion pressure

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Pulmonary and Respiratory Medicine


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