- Email: [email protected]
An Evaluation of Airway Resistance in Excised Artificially Ventilated Lungs
13TH ANNUAL ASPEN CONFERENCE ON RESEARCH IN EMPHYSEMA gram-negative or endotoxic shock and in acute hemorrhage in pigs. Wilson responded that the endothelial damage observed in the shock model occurred at the arteriolar and capillary level; the level shifted to the capillary venule level with heparin therapy. Stewart noted that the granulocyte has known proteolytic capacities and, secondly, that the pinocytotic
39S
vesicles in Wilson's illustrations appear to be opening toward the basement membrane. \Vilson affirmed Stewart's impression regarding the vesicles and stated that Karnovsky has also seen this phenomenon. He also observed that the interstitial edema and red cell diapedesis seen in shock lungs seem to he blocked by methyprednisolone sodium succinate.
An Evaluation of Airway Resistance m Excised Artificially Ventilated Lungs Normal vs Emphysema G. Wayne Silcers, BS .. ; Thomas L. Petty, M.D.; RogerS. Mitchell, M.D.; Giles F. Filley, .\J.D.; and John C. Maisel, M.D.
Airway resistance was determined in seven normal and 16 emphysematous lungs, using retrograde catheters to divide the- lung into peripheral airways, those less than 2-3 mm in diameter, and central airways, those larger than 2-3 mm in diameter. While ventilating the lungs in an artificial thorax, cinehronchograms were done to assess the degree of airway collapse on expiration in diseased versus nmmallungs. Observation of the postmortem cinehronchograms revealed that normal airways narrowed during the expiratory cycle at a constant rate, but they never closed or appeared to trap air. This was in contrast to the collapsing airways observed in the diseased lungs. In the diseased lungs, the airways collapsed in the early phase of the expiratory cycle. The peripheral retrograde catheter, which was in the 2-3 mm sized airways, showed rather uniform responses in the lungs without ailway collapse. At the start of expiration the pressure recorded by this catheter peaked at the same time as peak flow and began to fall approaching zero until at least 75 percent of the expiratory volume was expelled. A different response of the peripheral catheter pressure was noted in lungs with collapsing airways. Concomitant with or before collapse the peripheral catheter pressure abruptly increased and continued to rise throughout the expiratory cycle, indicating air trapping. The resistance data reveal that in the early stage of
expiration, peripheral airway resistance is increased in the diseased peripheral airways resulting in decreased flow and decreased intraluminal pressure in the central airways. This allows the equal pressure point to move upstream quicker in the diseased than in normal lungs. That portion of the airways which is downstream from the EPP may then collapse if transmural forces are great enough. If collapse does occur, there is a concurrent rise in central airway resistance which exceeds the peripheral airway resistance for the remainder of the expiratory cycle.
Discussion Thurlheck noted that others have also reported bronchial cartilage atrophy, hut also raised the possibility that luminal encroachment by mucus gland hyperplasia could contribute to central airways obstruction. Maisel showed histologic illustrations of the atrophy described and suggested that those looking for these areas should localize them by first demonstrating collapsibility and then marking these areas. S. Permutt, Baltimore, felt that the role of increased peripheral resistance had not been clarified. He stated that all of the findings presented by Silvers could be accounted for without an increase in collapsibility of diseased central bronchi. Pratt suggested measuring the pressures necessary to collapse these airways with the lung at residual volume.
Extent of Pigmentation in Autopsied Human Lungs as an Indicator of Particulate Environmental Air Pollution Philip C. Pratt, M.D., and Kaye H. Kilburn, M.D.
Preparation of lung specimens in inflation permits quantification of many aspects of morphology. In a study of some 250 non-emphysematous inflated lungs from adult men, the extent of pigmentation has been measured by a point-counting procedure. Using a grid of
CHEST, VOL. 59, NO. 5, MAY 1971 SUPPLEMENT
intersecting lines superimposed on a lung piece, all points which touch lung tissue and those which touch pigmented tissue are counted and the ratio is a measure of extent of pigmentation. Mter classification and measurement of pigmentation,
39S
vesicles in Wilson's illustrations appear to be opening toward the basement membrane. \Vilson affirmed Stewart's impression regarding the vesicles and stated that Karnovsky has also seen this phenomenon. He also observed that the interstitial edema and red cell diapedesis seen in shock lungs seem to he blocked by methyprednisolone sodium succinate.
An Evaluation of Airway Resistance m Excised Artificially Ventilated Lungs Normal vs Emphysema G. Wayne Silcers, BS .. ; Thomas L. Petty, M.D.; RogerS. Mitchell, M.D.; Giles F. Filley, .\J.D.; and John C. Maisel, M.D.
Airway resistance was determined in seven normal and 16 emphysematous lungs, using retrograde catheters to divide the- lung into peripheral airways, those less than 2-3 mm in diameter, and central airways, those larger than 2-3 mm in diameter. While ventilating the lungs in an artificial thorax, cinehronchograms were done to assess the degree of airway collapse on expiration in diseased versus nmmallungs. Observation of the postmortem cinehronchograms revealed that normal airways narrowed during the expiratory cycle at a constant rate, but they never closed or appeared to trap air. This was in contrast to the collapsing airways observed in the diseased lungs. In the diseased lungs, the airways collapsed in the early phase of the expiratory cycle. The peripheral retrograde catheter, which was in the 2-3 mm sized airways, showed rather uniform responses in the lungs without ailway collapse. At the start of expiration the pressure recorded by this catheter peaked at the same time as peak flow and began to fall approaching zero until at least 75 percent of the expiratory volume was expelled. A different response of the peripheral catheter pressure was noted in lungs with collapsing airways. Concomitant with or before collapse the peripheral catheter pressure abruptly increased and continued to rise throughout the expiratory cycle, indicating air trapping. The resistance data reveal that in the early stage of
expiration, peripheral airway resistance is increased in the diseased peripheral airways resulting in decreased flow and decreased intraluminal pressure in the central airways. This allows the equal pressure point to move upstream quicker in the diseased than in normal lungs. That portion of the airways which is downstream from the EPP may then collapse if transmural forces are great enough. If collapse does occur, there is a concurrent rise in central airway resistance which exceeds the peripheral airway resistance for the remainder of the expiratory cycle.
Discussion Thurlheck noted that others have also reported bronchial cartilage atrophy, hut also raised the possibility that luminal encroachment by mucus gland hyperplasia could contribute to central airways obstruction. Maisel showed histologic illustrations of the atrophy described and suggested that those looking for these areas should localize them by first demonstrating collapsibility and then marking these areas. S. Permutt, Baltimore, felt that the role of increased peripheral resistance had not been clarified. He stated that all of the findings presented by Silvers could be accounted for without an increase in collapsibility of diseased central bronchi. Pratt suggested measuring the pressures necessary to collapse these airways with the lung at residual volume.
Extent of Pigmentation in Autopsied Human Lungs as an Indicator of Particulate Environmental Air Pollution Philip C. Pratt, M.D., and Kaye H. Kilburn, M.D.
Preparation of lung specimens in inflation permits quantification of many aspects of morphology. In a study of some 250 non-emphysematous inflated lungs from adult men, the extent of pigmentation has been measured by a point-counting procedure. Using a grid of
CHEST, VOL. 59, NO. 5, MAY 1971 SUPPLEMENT
intersecting lines superimposed on a lung piece, all points which touch lung tissue and those which touch pigmented tissue are counted and the ratio is a measure of extent of pigmentation. Mter classification and measurement of pigmentation,