Effects of hyperinflation of the thorax on the mechanics of breathing

Grassino, A.; Lewinsohn, G; Tyler, John M.

doi:10.1152/jappl.1973.35.3.336

Cited by 33 publications

(11 citation statements)

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“…When points of equal V E are compared V T is reduced by Cf'Pb. These results agree in general with the above studies in man, However, the more rapid reduction of VL,E with hyperventilation after lung inflation than during normal carbon dioxide rebreathing implies some increased expiratory effort under conditions of CPPB perhaps related to increased abdominal muscle activity (Grassino et al, 1973;Urbschect, Bishop & Bachofen, 1973).…”

Section: Discussionsupporting

confidence: 91%

“…In man most studies have been of the few breaths immediately after lung inflation, but consistent findings are a fall in tidal volume and increase in respiratory frequency with a fall in total minute ventilation (Flenley, Pengelly & Milic-Emili, 1971;Grassino, Lewinsohn & Tyler, 1973;Green, Mead & Sears, 1978). In agreement with our findings Flenley et al (1971) found no prolongation of T e • Green et al (1978) found no change in the relative duration of inspiration and expiration, which is contrary to our findings.…”

Section: Discussionsupporting

confidence: 62%

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The Effects of Sustained Lung Inflation on the Pattern of Breathing in Man

Pearson¹,

Heath²

1981

Clinical Science

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1. Continuous positive-pressure breathing (CPPB) at airway pressures of 0.65-1.00 kPa above ambient pressure has been used to produce a sustained inflation of the lungs of approximately 1 litre in six normal male subjects. 2. Lung inflation produced a reduction in the ventilatory response to carbon dioxide inhalation by slow rebreathing in oxygen over approximately 45 min, with a reduction in the slope of the VE/Pet,CO2 and VT/Pet,CO2 relations (Pet,CO2, = end-tidal PCO2). 3. The pattern of breathing is altered, so that for any given expired minute ventilation (VE), tidal volume (VT) is reduced with a fall in breath duration (Tt) resulting from a decrease in inspiratory time (Ti) with no change in expiratory time (Te). 4. The break point on the VT/Ti relation is lowered.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 62%

The Effects of Sustained Lung Inflation on the Pattern of Breathing in Man

Pearson¹,

Heath²

1981

Clinical Science

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“…The mean factor responsible of this mechanical disadvantage is the perma nent high lung volume in obstructive diseases [23,72], There is also some evidence that CO2 breathing per se produced in man a small but statistically significant increase in total lung capacity by a centrally mediated vagal reflex [68]. It has been, moreover, demonstrated that in animals [52] as well as in man [32,49,50], the effectiveness of respiratory muscles as a pressure generator decreases by increasing lung volume. Hypercapnia in obstructive patients as well as in healthy subjects might increase the electrical activity of the phrenic nerve bursts, but the thoracomuscular apparatus might not be able to convert the central drive into an increased ventilation.…”

Section: Discussionmentioning

confidence: 99%

“…In the presence of mechanical impairment of the thoracopulmonary system it is very difficult to find an index of respiratory drive. In fact the response to CO2 is depressed also in normal subjects if the ventilation is loaded [10,14,18,27,53] or if the chest wall is hyperinsufflated by extrathoracic negative pressure [32] or by positive inspiratory pressure [24]. According to these observations, it seems misleading to evaluate the respiratory drive from ventilatory response in the presence of loaded breathing.…”

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confidence: 99%

Clinical Value of Rebreathing Test in Obstructive Lung Diseases

Marazzini¹,

Galli²,

Longhini³

1976

Respiration

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The ventilatory response to CO₂ inhalation, using rebreathing method, was studied in normal subjects and in patients with bronchial asthma and chronic obstructive lung disease. The patients with lung disease had flatter CO₂ response curves. However, if the ventilation was expressed as a fraction of the maximal voluntary ventilation, the difference between normal subjects and patients disappeared. The reduced ventilatory response of these patients may be of mechanical origin and not depending on reduced CO₂ sensitivity. The high lung volume of these patients may be the mean factor of the mechanical disadvantage of thoracomuscular system.

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“…This is the consequence of an improved compliance of the chest wall and the lungs [65], an improved respiratory muscle function, an increased respiratory drive [62] and a lowering oxygen consumption secondary to a decrease in work of breathing or an increase in efficiency of the respiratory muscle function or perhaps a reduction of chronic respiratory muscle fatigue [66 -68]. The relief of chronic respiratory muscle fatigue remains controversial, as well as the concept of chronic respiratory muscle fatigue.…”

Section: Nasal Noninvasive Positive Pressure Ventilationmentioning

confidence: 99%

Noninvasive ventilation and obstructive lung diseases

Cuvelier¹,

Muir²

2001

Eur Respir J

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Noninvasive ventilation and obstructive lung diseases. A. Cuvelier, J-F. Muir. #ERS Journals Ltd 2001. ABSTRACT: The key role of noninvasive positive pressure ventilation (NPPV) is well documented in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF) since it may avoid endotrachal intubation in w50% of cases when used as the initial treatment. However, currently only minimal data is available to assess usefulness of NPPV in COPD patients on a long-term basis. Even if such studies are difficult to manage, there is clearly a need for prospective studies comparing longterm oxygen therapy (LTOT) and NPPV in the most severe COPD in a large amount of patients and on a real long-term basis of several years. Two randomized prospective studies are being completed in Europe and the first preliminary results show that NPPV is associated with a reduction of hospitalization for chronic respiratory failure decompensation.The main beneficial effect of long-term mechanical ventilation in COPD patients with chronic respiratory failure implies a correction of nocturnal hypoventilation that could persist beyond the ventilation period because of a temporary improvement in carbon dioxide sensitivity that is often blunted in these patients.A synthesis from the literature suggest to consider NPPV for severe COPD patients who present with chronic hypoxia and hypercapnia and develop an unstable respiratory condition. Instability may be appreciated on a clinical basis and confirmed by a progressive worsening of arterial blood gas tensions, leading to frequent cardiorespiratory decompensations with ominous ARF episodes. NPPV should also be considered after an ARF episode successfully treated by noninvasive ventilation but with the impossibility to wean the patient from the ventilator.Thus, noninvasive positive pressure ventilation could be proposed as a preventive treatment in severe chronic obstructive pulmonary disease patients with unstable respiratory condition associated with fluctuating hypercapnia before, during and after an acute respiratory failure episode, avoiding the need for a tracheotomy. Adjunction of noninvasive ventilation to exercise rehabilitation is under evaluation.

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Effects of hyperinflation of the thorax on the mechanics of breathing

Cited by 33 publications

References 0 publications

The Effects of Sustained Lung Inflation on the Pattern of Breathing in Man

The Effects of Sustained Lung Inflation on the Pattern of Breathing in Man

Clinical Value of Rebreathing Test in Obstructive Lung Diseases

Noninvasive ventilation and obstructive lung diseases

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