oxygen to room air (especially when the saturation is only minimally depressed), Woolfs recommended 30minute wait to achieve a new equilibrium is reassuringly close to the 25 minutes recommended by Sherter~,et.;al.2 In most clinical situations an additional arterial blood sample will be needed, either for assessment of the adequacy of ventilation or of supplemental oxygen therapy. A 25- or 30-minute delay after changing the inspired oxygen pressure does appear adequate, as least in the ambulatory patients who were tested by both Sherter et al 2 and WOOH.4 Presumably the same limits apply to bedfast critically ill patients requiring extensive respiratory support, but this has not yet been determined. David W. CugeU, M.D., F.C.C.P. Department of Medicine Northwestern University Medical School, Chicago
1 Howe JP III, Alpert JS, Rickman FD, et al: Return of arterial pO'.! values to baseline after supplemental oxygen in patients with cardiac disease. Chest 87 :256-258, 1975 2 Sherter CB, Jabbour SM, Kovnat DM, et al: Prolonged .. rate of- decay of arterial P02 following oxygen breathing in chronic airways obstruction. Chest 67 :259-261, 1975 3 Cugell DW: How long should you wait? Chest 67 :253, 1975 4 Woolf CR: The diagnosis of emphysema: A physical sign, a roentgenographic sign and an oximeter test. Am Rev Respir Dis 80:705-715, 1959
To the Editor: Many months ago, when I reviewed the manuscript of Howe et al, l I was enthusiastic about the manuscript .but concerned lest inexperienced physicians extrapolate these data and presume that even patients with obstructive airway disease need only be removed from oxygen breathing for a short period of time before obtaining arterial blood gas levels which would properly reflect values while breathing room air. There was ample clinical experience from our own laboratory to indicate ~e need for a prolonged period of breathing room air in this circumstance. I also recalled having read many years previously a published report of a systematic study of this problem an"d thought I could easily prevent. misunderstanding by bringing the report to the authors' attention and suggesting that they quote it. Unfortunately, despite a diligent search of the literature of the last 20 years, the report could not be found. We found only one paper which related to the problem, 2 and it provided only limited treatment of the subject. The recent arrival of Dr. Woolfs letter was an occasion for some excitement; a hurried trip to the library confinned that his was the lost report! The incident reminded me of the late Dr. J. C. B. Grant's description 4 of an important attribute of the ideal physician: "a memory which is wax to receive impressions and marble to retain them." Alas, my memory was neither wax to impressions nor marble to retain,
CHEST, 69: 6, JUNE, 1976
and the titles of Dr. Woolfs report of 1959 5 and of the preceding report on methods published in 19566 did not provide us with a strong enough clue so that we could readily retrieve these studies from a search of the literature. We perhaps should have, but did not, recognize the 1959 report from the words, "diagnosis of emphysema" and "oximeter test." In this current era of enonnously increased volume of periodical medical literature, this experience indicates, I believe, the need for great care on the part of authors in writing titles for their articles so that readers of all possible interests will be able to retrieve all of the infonnation contained in them. It also indicates the need for serious consideration by medical editors for the publication of key index words, in addition to titles, to make the task of medical indexers easier and more effective. The conclusion reached by Dr. WooH that in the patient with chronic obstructive pulmonary disease, one should wait 30 minutes after changing from oxygen to room air breathing before drawing arterial blood samples which will represent the ambient air state is not very different from the recommendation by Sherter et al8 to wait "at least 25 minutes" Wlder these conditions. Gordon L. Snider, M.D., F.C.C.P. Professor of Medicine Boston University School of Medicine and Chief, Pulmonary Section Veterans Administration Hospital, Boston
1 Howe JP III, Alpert JS, Rickman FD, et al: Return of
2
3
4
5 6
arterial P02 values to baseline after supplemental oxygen in patients with cardiac disease. Chest ff7 :256-258, 1975 Massaro DJ, Katz S, Luchsinger PC: Effect of various modes of oxygen administration on the arterial gas values in patients with respiratory acidosis. Br Med J 2:627-629, 1962 Sherter CB, Jabbour SM, Kovnat DM, et a1: Prolonged rate of decay of arterial P02 following oxygen breathing in chronic airways obstruction. Chest 67 :259-261, 1975 Grant }CB: A Method of Anatomy: Descriptive and Deductive. Baltimore, W Wood and Co, 1937, preface Woolf CR: The diagnosis of emphysema: A physical sign, a roentgenographic sign and an oximeter test. Am Rev Respir Dis 80:705-715, 1959 Woolf CR, Gunton RW, Paul W: Simple tests of respiratory function using a direct writing ear oximeter. Am Rev Respir Dis 74:511-532, 1956
Diffuse Interstitial Fibrosing Pneumonitis Scanning Electron Microscopic Study To the Editor: The scanning electron microscope was used to investigate the fine structure of diffuse interstitial 6brosing pneumonitis.
COMMUNICATIONS TO THE EDITOR 809
FiGURE 1. Stone-wall-like appearance of proliferated alveolar lining cells of type 2 with numerous microvilli (original magnification X 1,(00).
CASE REPoRT
A 54-year-old man was already reportedl because adenoviral particles were observed with the transmission electron microscope in the nuclei of alveolar epithelial cells, infiltrated plasma cells, and alveolar macrophages. With regular histopathologic findings, the alveolar spaces were narrowed, with thickening of the alveolar walls due to extensive proliferation of collagen fibers and cell infiltration, and with organized intra-alveolar exudates. Proliferation of cuboidal alveolar epithelial cells was observed. In sonte areas, PAS-positive granular pneumocytes were desquamated. These findings were considered to be those of usual interstitial pneumonitis and partially of desquamative interstitial pneumonitis as described by Liebow et al.2 Scanning Electron Microscopic Preparation
Specimens were medin a 2.5-percent solution of buffered glutaraldehyde, followed by washing with phosphate buffer (pH 7.3), and were remed with a l-percent solution of osmium tetroxide. After dehydration with a series of ethanol and acetone, the specimens were applied to a critical-point dryer and then were coated doubly with carbon and gold. With scanning electron microscopic examination, stonewall-like proliferation of cuboidal alveolar epithelial cells (type-2 cells) was noted (Fig 1). On the surface of the cells, many microvilli were observed, which have already been seen with transmission electron microscopic examination.3 In some parts the surfaces of alveolar lining cells were covered with fibrinous materials and cells, and in other parts, ablation of a layer of alveolar lining cells was observed, which might accord with the desquamation of cells characteristic of the desquamative interstitial pneumonitis-like feature of this case (Fig 2). DISCUSSION
Many ultrafine structural investigations by transmission electron microscopy on diffuse interstitial fibrosing
810 COMMUNICATIONS TO THE EDITOR
FiGURE 2. Fibrinous exudates and alveolar macrophages on surface of alveolar lining cells. Ablation of layer of alveolar lining cells was seen at right middle portion (X 3(0).
pneumonitis have been reported; however, to our knowledge, there has been no previous report of this disease being investigated by scanning electron microscopy. The critical-point dryer improved the preservation of tissue for scanning electron microscopic examination, and this technique makes investigation of alveolar fine structure possible.· The application of scanning electron micr0scopy to diffuse interstitial pneumonitis disclosed the expected appearances of this disease. Takeshi Kawai, M.D., F.e.e.p., Depaf'tment at Medicine and Tatsu;i Fujiwara, Electron MicroIcopf/ Lalxmztotv Keio University School at Medicine, Toltrio' Reprint requests: Dr. Kawai, Keio Univetritv School at Medi-
cine, Shin;uku, Tokyo 160, Japan
REF'ERENCFS 1 Kawai T, Fujiwara T, Aoyama Y, et al: Diffuse interstitial fibrosing pneumonitis and adenovirus infection. Chest 69: 692-693,1976 2 Liebow AA, Steer A, Billingsley JG: Desquamative mtel'" stitial pneumonia. Am J Med 39:369, 1965 3 Okada Y: Electron microscopic study of interstitial pneumonia, with special reference to alveolar epithelial cells. Acta Pathol Jpn 22:811, 1972 4 Kuhn C 1lI, Finke EH: The topography of the pulmonary alveolus: Scanning electron microscopy using different 6u.tions. J Ultrastructure 38:161,1972
CHEST, 69: 6, JUNE, 1976
1 Howe JP III, Alpert JS, Rickman FD, et al: Return of arterial pO'.! values to baseline after supplemental oxygen in patients with cardiac disease. Chest 87 :256-258, 1975 2 Sherter CB, Jabbour SM, Kovnat DM, et al: Prolonged .. rate of- decay of arterial P02 following oxygen breathing in chronic airways obstruction. Chest 67 :259-261, 1975 3 Cugell DW: How long should you wait? Chest 67 :253, 1975 4 Woolf CR: The diagnosis of emphysema: A physical sign, a roentgenographic sign and an oximeter test. Am Rev Respir Dis 80:705-715, 1959
To the Editor: Many months ago, when I reviewed the manuscript of Howe et al, l I was enthusiastic about the manuscript .but concerned lest inexperienced physicians extrapolate these data and presume that even patients with obstructive airway disease need only be removed from oxygen breathing for a short period of time before obtaining arterial blood gas levels which would properly reflect values while breathing room air. There was ample clinical experience from our own laboratory to indicate ~e need for a prolonged period of breathing room air in this circumstance. I also recalled having read many years previously a published report of a systematic study of this problem an"d thought I could easily prevent. misunderstanding by bringing the report to the authors' attention and suggesting that they quote it. Unfortunately, despite a diligent search of the literature of the last 20 years, the report could not be found. We found only one paper which related to the problem, 2 and it provided only limited treatment of the subject. The recent arrival of Dr. Woolfs letter was an occasion for some excitement; a hurried trip to the library confinned that his was the lost report! The incident reminded me of the late Dr. J. C. B. Grant's description 4 of an important attribute of the ideal physician: "a memory which is wax to receive impressions and marble to retain them." Alas, my memory was neither wax to impressions nor marble to retain,
CHEST, 69: 6, JUNE, 1976
and the titles of Dr. Woolfs report of 1959 5 and of the preceding report on methods published in 19566 did not provide us with a strong enough clue so that we could readily retrieve these studies from a search of the literature. We perhaps should have, but did not, recognize the 1959 report from the words, "diagnosis of emphysema" and "oximeter test." In this current era of enonnously increased volume of periodical medical literature, this experience indicates, I believe, the need for great care on the part of authors in writing titles for their articles so that readers of all possible interests will be able to retrieve all of the infonnation contained in them. It also indicates the need for serious consideration by medical editors for the publication of key index words, in addition to titles, to make the task of medical indexers easier and more effective. The conclusion reached by Dr. WooH that in the patient with chronic obstructive pulmonary disease, one should wait 30 minutes after changing from oxygen to room air breathing before drawing arterial blood samples which will represent the ambient air state is not very different from the recommendation by Sherter et al8 to wait "at least 25 minutes" Wlder these conditions. Gordon L. Snider, M.D., F.C.C.P. Professor of Medicine Boston University School of Medicine and Chief, Pulmonary Section Veterans Administration Hospital, Boston
1 Howe JP III, Alpert JS, Rickman FD, et al: Return of
2
3
4
5 6
arterial P02 values to baseline after supplemental oxygen in patients with cardiac disease. Chest ff7 :256-258, 1975 Massaro DJ, Katz S, Luchsinger PC: Effect of various modes of oxygen administration on the arterial gas values in patients with respiratory acidosis. Br Med J 2:627-629, 1962 Sherter CB, Jabbour SM, Kovnat DM, et a1: Prolonged rate of decay of arterial P02 following oxygen breathing in chronic airways obstruction. Chest 67 :259-261, 1975 Grant }CB: A Method of Anatomy: Descriptive and Deductive. Baltimore, W Wood and Co, 1937, preface Woolf CR: The diagnosis of emphysema: A physical sign, a roentgenographic sign and an oximeter test. Am Rev Respir Dis 80:705-715, 1959 Woolf CR, Gunton RW, Paul W: Simple tests of respiratory function using a direct writing ear oximeter. Am Rev Respir Dis 74:511-532, 1956
Diffuse Interstitial Fibrosing Pneumonitis Scanning Electron Microscopic Study To the Editor: The scanning electron microscope was used to investigate the fine structure of diffuse interstitial 6brosing pneumonitis.
COMMUNICATIONS TO THE EDITOR 809
FiGURE 1. Stone-wall-like appearance of proliferated alveolar lining cells of type 2 with numerous microvilli (original magnification X 1,(00).
CASE REPoRT
A 54-year-old man was already reportedl because adenoviral particles were observed with the transmission electron microscope in the nuclei of alveolar epithelial cells, infiltrated plasma cells, and alveolar macrophages. With regular histopathologic findings, the alveolar spaces were narrowed, with thickening of the alveolar walls due to extensive proliferation of collagen fibers and cell infiltration, and with organized intra-alveolar exudates. Proliferation of cuboidal alveolar epithelial cells was observed. In sonte areas, PAS-positive granular pneumocytes were desquamated. These findings were considered to be those of usual interstitial pneumonitis and partially of desquamative interstitial pneumonitis as described by Liebow et al.2 Scanning Electron Microscopic Preparation
Specimens were medin a 2.5-percent solution of buffered glutaraldehyde, followed by washing with phosphate buffer (pH 7.3), and were remed with a l-percent solution of osmium tetroxide. After dehydration with a series of ethanol and acetone, the specimens were applied to a critical-point dryer and then were coated doubly with carbon and gold. With scanning electron microscopic examination, stonewall-like proliferation of cuboidal alveolar epithelial cells (type-2 cells) was noted (Fig 1). On the surface of the cells, many microvilli were observed, which have already been seen with transmission electron microscopic examination.3 In some parts the surfaces of alveolar lining cells were covered with fibrinous materials and cells, and in other parts, ablation of a layer of alveolar lining cells was observed, which might accord with the desquamation of cells characteristic of the desquamative interstitial pneumonitis-like feature of this case (Fig 2). DISCUSSION
Many ultrafine structural investigations by transmission electron microscopy on diffuse interstitial fibrosing
810 COMMUNICATIONS TO THE EDITOR
FiGURE 2. Fibrinous exudates and alveolar macrophages on surface of alveolar lining cells. Ablation of layer of alveolar lining cells was seen at right middle portion (X 3(0).
pneumonitis have been reported; however, to our knowledge, there has been no previous report of this disease being investigated by scanning electron microscopy. The critical-point dryer improved the preservation of tissue for scanning electron microscopic examination, and this technique makes investigation of alveolar fine structure possible.· The application of scanning electron micr0scopy to diffuse interstitial pneumonitis disclosed the expected appearances of this disease. Takeshi Kawai, M.D., F.e.e.p., Depaf'tment at Medicine and Tatsu;i Fujiwara, Electron MicroIcopf/ Lalxmztotv Keio University School at Medicine, Toltrio' Reprint requests: Dr. Kawai, Keio Univetritv School at Medi-
cine, Shin;uku, Tokyo 160, Japan
REF'ERENCFS 1 Kawai T, Fujiwara T, Aoyama Y, et al: Diffuse interstitial fibrosing pneumonitis and adenovirus infection. Chest 69: 692-693,1976 2 Liebow AA, Steer A, Billingsley JG: Desquamative mtel'" stitial pneumonia. Am J Med 39:369, 1965 3 Okada Y: Electron microscopic study of interstitial pneumonia, with special reference to alveolar epithelial cells. Acta Pathol Jpn 22:811, 1972 4 Kuhn C 1lI, Finke EH: The topography of the pulmonary alveolus: Scanning electron microscopy using different 6u.tions. J Ultrastructure 38:161,1972
CHEST, 69: 6, JUNE, 1976
