Chest
Original Research: Prolonged Mechanical VentilationEffect of Home Mechanical Ventilation on Inspiratory Muscle Strength in COPD
Section snippets
Patients
Thirty-four consecutive patients with COPD and chronic HRF electively admitted for establishment of NIV were enrolled in this study. Nine patients, however, dropped out during the adaptation period because they could not tolerate NIV. Since the study was conceived to test physiologic rather than clinical outcomes, data from these subjects were not further analyzed. Thus, this report contains the data of the remaining 25 patients (14 men; mean [± SD] body mass index, 22.5 ± 4.7 kg/m2; age, 60.0
Results
Blood gas and lung function data are presented in Table 1. All patients had chronic HRF with daytime hypercapnia and hypoxemia. Furthermore, vital capacity and FEV1 were reduced in keeping with the diagnosis of severe COPD. No change in FRC (measured as thoracic gas volume) was observed after NIV (Table 1).
Data from the hours counter on the machines used showed that the NIV patients had used the machines for a median of 7.1 h per night, reflecting good compliance. While by study design all
Discussion
The main finding of this study is that in patients with chronic HRF due to severe COPD, successful application of NIV does not result in an increase in Tw Pdi. This suggests that low-frequency diaphragm fatigue is not present in such patients prior to therapy. Discussion of the significance of these data will follow a critique of the methods.
References (35)
- et al.
Effect of negative pressure ventilation in severe chronic obstructive pulmonary disease
Lancet
(1992) - et al.
Effect of nasal pressure support ventilation and external PEEP on diaphragmatic activity in patients with severe stable COPD
Thorax
(1993) - et al.
The appropriate setting of noninvasive pressure support ventilation in stable COPD patients
Chest
(2000) - et al.
Outcome of domiciliary nasal intermittent positive pressure ventilation in restrictive and obstructive disorders
Thorax
(1995) - et al.
Nasal pressure support ventilation plus oxygen compared with oxygen therapy alone in hypercapnic COPD
Am J Respir Crit Care Med
(1995) Noninvasive ventilation: does it work, for whom, and how?
Am Rev Respir Dis
(1993)- et al.
Rationale for the use of non-invasive ventilation in chronic respiratory failure
Thorax
(2000) - et al.
Noninvasive ventilation has not been shown to be ineffective in stable COPD
Am J Respir Crit Care Med
(2000) Domiciliary ventilation in chronic obstructive lung disease
Thorax
(1992)Noninvasive ventilation has been shown to be ineffective in stable COPD
Am J Respir Crit Care Med
(2000)
Pattern of recovery from diaphragmatic fatigue over 24 hours
J Appl Physiol
Exhaustive treadmill exercise does not reduce twitch transdiaphragmatic pressure in patients with COPD
Am J Respir Crit Care Med
Diaphragm strength in chronic obstructive pulmonary disease
Am J Respir Crit Care Med
Lung volumes and forced ventilatory flows: report Working Party Standardization of Lung Function Tests, European Community for Steel and Coal; Official Statement of the European Respiratory Society
Eur Respir J Suppl
Maximal respiratory pressures: normal values and relationships to age and sex
Am Rev Respir Dis
The ventilatory capacity in healthy subjects: an analysis of causal factors with special reference to the respiratory forces
Scand J Clin Lab Invest
A simple method for assessing the validity of the esophageal balloon technique
Am Rev Respir Dis
Cited by (21)
Oxygen Therapy and Noninvasive Ventilation in Chronic Obstructive Pulmonary Disease
2020, Clinics in Chest MedicineVentilatory support during sleep in patients with chronic obstructive pulmonary disease
2014, Sleep Medicine ClinicsCitation Excerpt :First, it has been shown that the respiratory muscles of hypercapnic COPD patients work hard but are not fatigued; they seem to act as wise fighters, thereby deliberately keeping respiratory muscle work below the fatigue threshold at the expense of decreased tidal volumes and thus alveolar hypoventilation.13 Second, most studies on NIV in COPD have not shown any effects on maximal respiratory muscle pressures independent from changes in lung volumes,14 arguing against the hypothesis that if the muscles are rested, they should gain (reserve) capacity. As a consequence, instead of resting fatigued respiratory muscles, NIV might, among other things, lead to a decrease in respiratory muscle work through the induction of a more favorable breathing pattern, a pattern that can be maintained during the day.
Nocturnal Ventilation in Chronic Hypercapnic Respiratory Diseases
2012, Therapy in Sleep MedicineEffects of non-invasive positive pressure ventilation (NIPPV) in stable chronic obstructive pulmonary disease (COPD)
2008, Respiratory Medicine: COPD UpdatePrognostic value of mouth occlusion pressure in patients with chronic ventilatory failure
2007, Respiratory Medicine
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
The authors have no financial or other potential conflicts of interest to disclose.