Effect of increased lung recoil pressure on maximal expiratory flow in normal subjects

Stubbs, Samuel E.; Hyatt, Robert E.

doi:10.1152/jappl.1972.32.3.325

Cited by 68 publications

(47 citation statements)

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“…The average decrease in VC was 31.5%, TLC 28.5%, FRC 27%, and RV 20%. The restriction imposed by chest strapping in the present study was, thus, similar to that ob tained in previous studies [2,9,10,16,17]. Also consistent with previous studies was the observation that in each subject, restric tion of the chest shifted the static PV curve of the lung to the right: the individual expi ratory PV curves before and during strap ping are shown in figure 2.…”

Section: General Effects Of Chest Restriction On Lung Mechanicssupporting

confidence: 91%

“…This finding suggested that the fall in FRC was primarily due to a decrease in the tendency of the chest wall to recoil outward. In more recent investigations, the esophageal pressure, instead of being de creased, appeared to be about equal in the strapped and nonstrapped states at the re spective resting lung volumes [16,17]; this has essentially the same significance as our own data and is also strong evidence that a decrease in the outward pull of the chest wall largely participates in the fall in FRC during strapping.…”

Section: General Effects Of Chest Restriction On Lung Mechanicssupporting

confidence: 77%

“…Al though they felt that this alteration was due to the closing of lung units, they did not ex clude the possibility that it could be related to changes in the surface properties of the alveolar lining layer. Thus, the cause of the increased recoil was not clear and, accord ingly, several studies have been devoted to the alterations in the mechanical properties of the lung [9,16,17].…”

Section: Introductionmentioning

confidence: 99%

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Mechanics of the Chest Wall during Restrictive Thoracic Strapping

Troyer¹

1980

Respiration

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We studied respiratory mechanics in 4 young men during restrictive thoracic strapping. In particular, we obtained passive pressure-volume (PV) characteristics of the chest wall during voluntary relaxation. The effects on lung mechanics were similar to those observed in previous studies in that lung recoil pressure (Pst [L]) increased at any volume and compliance decreased. In each subject, strapping decreased both FRC and Pst (L) at FRC, and transposed the deflation chest wall PV curve to lower volumes at any given transthoracic pressure. Moreover, strapping flattened the slope of the curve: the average chest wall compliance decreased from 0.229 to 0.106 liters/cm H₂O. These changes are shown to be due to the fact that the (inward) force exerted by the strap on the chest wall is higher when the thorax is inflated than when it is deflated. It is estimated that the elastic work of breathing is increased by strapping, and that this increase is almost entirely due to the work done on the chest wall. Despite the lower lung compliance, the work required to overcome the elastic forces of the lung is not increased during strapping

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Section: General Effects Of Chest Restriction On Lung Mechanicssupporting

confidence: 91%

Section: General Effects Of Chest Restriction On Lung Mechanicssupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanics of the Chest Wall during Restrictive Thoracic Strapping

Troyer¹

1980

Respiration

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“…Strapping the chest wall has been observed to produce similar changes in spirometry and flow. 28 Knudson et al12 defined the lower limit of normal as that value above which the results of 95% of the normal population lie. In general, our findings in an older urban population are consistent with those of Knudson et al, particularly for women.…”

Section: Discussionmentioning

confidence: 99%

Maximal expiratory flow-volume curves in Londoners aged 60 years and over.

Fowler¹,

Pluck²,

Hetzel³

1987

Thorax

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To obtain more accurate information about respiratory function in the elderly, we carried out spirometry and constructed maximum expiratory flow-volume curves in 136 volunteers over the age of 60 years (90 women, 46 men). Significant age related differences were found. Although vital capacity appeared well preserved in all groups, mid expiratory flow rates were low, even in lifelong non-smokers. On the basis of previous work, many of the subjects in this study would have been assessed as having small airways obstruction. The number of subjects is larger than in previous studies of airflow in this age group. Old people have often smoked, and many have a history of cardiovascular disease. Such individuals were included provided that they were fit and active for their age, and had no overt respiratory disease. It is argued that our findings will be of more clinical relevance to the elderly population than values derived either from population studies or studies that have used rigorous selection criteria to exclude subjects who smoked or had a history of non-respiratory disease.Respiratory disease is common, and its prevalence increases with age. though the way in which subjects were selected (and the inclusion of smokers) may be responsible. None of these studies report flow rates. The recent report from Knudson's group,"2 including a separate analysis of the results from elderly women, is probably the best current source of reference values for this age group. This report also shows the discrepancies that arise (which appear to increase with age) when different recommendations13-15 are followed for the measurement of flow rates from the flow-volume curve. Schoenberg's study,5 which adopted a curvilinear relationship between lung function and age, is also relevant to this age group, though the numbers are small. Other studies'6 17 include too few elderly subjects and too little methodological detail for current use in this age group.Our study tries to provide more information by reporting the results of spirometry and measurement of maximal expiratory flow in a volunteer group of healthy white Londoners aged 60 years and over. People who survive into old age rarely escape physical insults, and we have therefore included those with a history of non-respiratory disease. We have also included smokers, because lifelong non-smoking men are a small, possibly unrepresentative, fraction of the elderly population.

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“…When FVC was limited via CWS to 50% of the unstrapped vital capacity, expiratory airflows increased by approximately 60%. 16,17 The higher expiratory airflow with CWS was caused by increased elastic recoil of the lung. 16,17 This suggests that an allograft that is limited in inflation because of a smaller recipient thorax would have increased elastic recoil, a major determinant of expiratory airflow.…”

Section: Possible Mechanisms Associating Lung Size Mismatch With Survmentioning

confidence: 99%