Evidence for chronic inflammation as a component of the interstitial lung disease associated with progressive systemic sclerosis

Comparison of three methods for measuring respiratory mechanics in ventilated children

Continuous measurements of airway pressure, gas flow, and tidal volume were made in 22 mechanically ventilated children, both during steady state conditions and following airway occlusion at end-inflation. For each child, three methods of analyzing the stored data were used to generate values of respiratory system compliance and resistance: 1) end-inspiratory hold technique (Bone: Respir Care 28:597, 1983; Rossi et al. Am Rev Respir Dis 131:672, 1985); 2) constant flow technique (Rossi et al. J Appl Physiol 58:1849, 1985; Suratt et al. J Appl Physiol 49:1116, 1980); and 3) multiple linear regression (Roy et al. Comput Biomed Res 7:21, 1974; Bhutani et al. Pediatr Pulmonol 4:150, 1988). In the absence of an accepted standard, we used the inspiratory hold technique as a reference. All methods gave comparable values for respiratory mechanics over a wide clinical range. However, multiple linear regression was the most convenient of the three: it can be automated and continuously displayed, there is no subjective input, values are taken through the respiratory cycle, and it is completely noninvasive. We also found that respiratory system resistance was largely a measure of endotracheal tube resistance and that respiratory compliance is a more sensitive monitor of lung function in intubated children.

Characteristics and clinical significance of the lymphocytic alveolitis in interstitial lung disorders

Although the mechanisms responsible for lung damage and respiratory function deterioration for each type of alveolitis are not entirely known, with the opportunity to study the cells present in the lower respiratory tract, their functions and the mediators released in different conditions, we will be able to better understand the link between the inflammatory process, the acute tissue damage, the progression of the disease and the pulmonary scarring. This knowledge will be helpful in a better management of patients with interstitial lung diseases modulated by immunologic mechanisms.

Subclinical alveolitis in immunologic systemic disorders

Subclinical alveolitis is a frequent finding in immunologic systemic disorders. However the significance of subclinical alveolar inflammation does not seem to be univocal and varies according to the disease. The fact that pulmonary involvement is rare during the course of extrathoracic granulomatosis like Crohn's disease or primary cirrhosis and that subclinical alveolitis is frequent suggests that alveolar inflammation may be the expression in the lung of a systemic immune disorder. In contrast subclinical alveolitis in collagen-vascular diseases, particularly progressive systemic sclerosis, is frequently associated with abnormalities of lung parenchyma as assessed by CT scan supporting the hypothesis that subclinical alveolitis is associated with development of ILD. Close follow-up of these patients is needed to better determine whether subclinical alveolitis precedes ILD and whether early detection of subclinical alveolitis in immunologic systemic disorders may identify those patients that are at risk for the development of ILD in the future.

A possible role for transforming growth factor-beta in systemic sclerosis

The cause of systemic sclerosis remains unknown, but cellular and molecular mechanisms possibly responsible for the characteristic clinical manifestations of fibrosis and vascular damage (Raynaud's phenomenon, telangiectasis, digital infection, and renal arteriopathy) are becoming understood in greater detail. One possibly important cytokine is transforming growth factor-beta (TGF-beta); its involvement is reviewed here. With regard to vascular lesions, TGF-beta has variably been shown to inhibit endothelial cell growth in vitro but to promote angiogenesis in vivo, a paradox that remains unresolved. Nonetheless, an injurious activity of TGF-beta on microvascular endothelial cells could help to explain the intimal proliferation and microvascular obliteration seen. Whether as a result of or as a cause of endothelial cell damage, platelet activation has been well documented in systemic sclerosis and the platelet alpha granule pool contains a large quantity of TGF-beta. TGF-beta is also produced by activated macrophages and T cells, both of which are known to occur within systemic sclerosis lesions. An important effect of TGF-beta is its stimulation of fibroblast collagen and fibronectin synthesis and their deposition into the extracellular matrix. Stimulation by TGF-beta may therefore account for the fibrosis seen in the dermis and in the internal organs. Direct evidence of TGF-beta involvement in systemic sclerosis is scanty, and awaits discovery of either an abnormal expression of or response to TGF-beta. The biologic effects of TGF-beta appear to be regulated at the level of activation from a latent polypeptide precursor form. Descriptions of the importance of this cytokine in pathologic conditions will need to account for this activation and its regulation. Nonetheless, the physiologic effects so far attributed to TGF-beta make its involvement in systemic sclerosis an attractive possibility to explain some of the manifestations of this enigmatic disease.

Reversal of acute exacerbations of chronic obstructive lung disease by inspiratory assistance with a face mask

BACKGROUND

Patients with acute exacerbations of chronic obstructive pulmonary disease may require endotracheal intubation with mechanical ventilation. We designed, and here report on the efficacy of, a noninvasive ventilatory-assistance apparatus to provide inspiratory-pressure support by means of a face mask.

METHODS

We assessed the short-term (45-minute) physiologic effects of the apparatus in 11 patients with acute exacerbations of chronic obstructive pulmonary disease and evaluated its therapeutic efficacy in 13 such patients (including 3 of the 11 in the physiologic study) who were treated for several days and compared with 13 matched historical-control patients.

RESULTS

In the physiologic study, after 45 minutes of inspiratory positive airway pressure by face mask, the mean (+/- SD) arterial pH rose from 7.31 +/- 0.08 to 7.38 +/- 0.07 (P less than 0.01), the partial pressure of carbon dioxide fell from 68 +/- 17 mm Hg to 55 +/- 15 mm Hg (P less than 0.01), and the partial pressure of oxygen rose from 52 +/- 12 mm Hg to 69 +/- 16 mm Hg (P less than 0.05). These changes were accompanied by marked reductions in respiratory rate (from 31 +/- 7 to 21 +/- 9 breaths per minute, P less than 0.01). Only 1 of the 13 patients treated with inspiratory positive airway pressure needed tracheal intubation and mechanical ventilation, as compared with 11 of the 13 historical controls (P less than 0.001). Two patients in each group died. As compared with the controls, the treated patients had a more transient need for ventilatory assistance (3 +/- 1 vs. 12 +/- 11 days, P less than 0.01) and a shorter stay in the intensive care unit (7 +/- 3 vs. 19 +/- 13 days, P less than 0.01).

CONCLUSIONS

Inspiratory positive airway pressure delivered by a face mask can obviate the need for conventional mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.

Auto-PEEP and dynamic hyperinflation in COPD patients during controlled mechanical ventilation and high frequency jet ventilation

We investigated the levels of auto-PEEP and dynamic hyperinflation during high frequency jet ventilation (HFJV) and controlled mechanical ventilation (CMV) in six patients with chronic obstructive pulmonary disease within the first 36 h of acute exacerbation. The comparative evaluation was performed at similar conditions of gas exchange in HFJV and CMV: PaO2 77.6 +/- 11 mmHg vs 80.8 +/- 12 mmHg; PaCO2 46.8 +/- 2.5 mmHg vs 47 +/- 2.8 mmHg; pH 7.38 vs 7.38. In this situation, the values of auto-PEEP and dynamic hyperinflation, expressed as delta over the apneic functional residual capacity (FRC) did not differ: (auto-PEEPHFJV 8.9 +/- 3.8 cmH2O; auto-PEEPCMV 8.8 +/- 4.7 cmH2O; delta FRCHFJV 0.56 +/- 0.19 l; delta FRCCMV 0.54 +/- 0.2 l). This result suggests that, with a suitable machine setting and similar gas exchanges, HFJV produces the same level of auto-PEEP and dynamic hyperinflation as CMV in patients with chronic obstructive pulmonary disease.

Dose-response effects and time course of effects of inhaled fenoterol on respiratory mechanics and arterial oxygen tension in mechanically ventilated patients with chronic airflow obstruction

To investigate the dose-response relationship and the time course of the effects of fenoterol (a selective beta 2-adrenergic agonist) on respiratory function in mechanically ventilated patients with acute respiratory failure due to exacerbation of chronic airflow obstruction (CAO), seven consecutive acutely ill patients were studied within 3 days of the onset of mechanical ventilation. Airflow, airway pressure, and changes in lung volume were measured with the transducers of the 900 C Servo Ventilator, the last by electronic integration. The end-expiratory lung volume (EELV), the intrinsic positive end-expiratory pressure (PEEPi), the static respiratory compliance (Cstrs), maximum and minimum respiratory resistance (Rrsmax and Rrsmin), and arterial oxygen tension (PaO2), were measured under control conditions (all patients were receiving aminophylline infused at a constant rate) 5, 15, and 30 min after administration of 4 ml aerosolized saline solution and 5, 15, and 30 min after inhalation of 0.4, 0.8, and 1.2 mg fenoterol. After the last dose, measurements were repeated at 60, 120, and 180 min. We found that, on average, while saline did not cause any significant change in respiratory mechanics, a low dose (0.4 mg) of inhaled fenoterol was followed by a rapid (5 min) and significant decrease in Rrsmax (-33%), Rrsmin (-28%), EELV (-34%), and PEEPi (-44%), with a slight but not significant further fall with higher doses. However, changes were short-lasting, and by 2 h after the end of administration were no longer significant. PaO2 dropped significantly on average, with a maximum mean fall of 15 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for protein oedema, neutrophil influx, and enhanced collagen production in lungs of patients with systemic sclerosis

Bronchoalveolar lavage fluid from patients with systemic sclerosis was analysed for evidence of pulmonary vascular leakage, inflammatory cell influx, and enhanced type III collagen synthesis. Eighteen patients with systemic sclerosis and computed tomographic evidence of fibrosing alveolitis were compared with 16 patients with a normal scan. The albumin concentration in lavage fluid was higher in all patients than in normal volunteers. Patients with an abnormal computed tomogram as a group had increased proportions of all inflammatory cell types, whereas those with a normal scan had increased neutrophils only. Increased lavage type III procollagen peptides were found in all patients with an abnormal computed tomogram and eight of those with a normal scan. These results suggest that pulmonary vascular leakage and neutrophil influx may be early pathological features of lung disease in systemic sclerosis and frequently associated with enhanced collagen production. Thus lavage of patients with systemic sclerosis may identify lung inflammation and altered collagen metabolism early in the evolution of fibrosing alveolitis.

Effects of the heat-moisture exchangers on dynamic hyperinflation of mechanically ventilated COPD patients

In recent years the use of devices called Heat and Moisture Exchangers (HME) has become widespread as gas conditioners for ICU patients requiring mechanical ventilation. As an important variation of the resistive properties of the HME, related to flow and duration of use, has recently been pointed out during "in vitro" studies, the use of these devices in COPD patients could increase the levels of auto PEEP and dynamic hyperinflation. In this study we have compared the levels of auto PEEP and difference in functional residual capacity (delta FRC) in a group of COPD patients, requiring controlled mechanical ventilation (CMV), at basal conditions and after the insertion into the circuit of three HMEs (Dar Hygrobac, Pall Ultipor, Engstrom Edith) at random: the results obtained excluded a significant increase of auto PEEP and delta (FRC) both with "new" HMEs and after 12 h of continuous use.

Effects of an inhaled corticosteroid, budesonide, on alveolar macrophage function in smokers

Selected functions of alveolar macrophages obtained by bronchoalveolar lavage of 12 healthy smokers were examined before and after eight weeks' treatment with an inhaled glucocorticosteroid, budesonide (400 micrograms twice daily). After budesonide treatment spontaneous as well as opsonised zymosan triggered prostaglandin E2 (PGE2) secretion from harvested cells was reduced; no such reduction in opsonised zymosan triggered leukotriene B4 (LTB4) production was observed. Neither the capacity to phagocytose opsonised yeast particles nor the superoxide radical generation triggered by the calcium ionophore A23187, 4 beta-phorbol 12-myristate 13-acetate (PMA), or opsonised zymosan ex vivo were more than marginally affected by the glucocorticosteroid treatment in vivo. Lavage fluid concentrations of angiotensin converting enzyme (ACE), however, after treatment were twice those before treatment and concentrations of fibronectin were reduced to half. Albumin concentrations in lavage fluid were not affected by the glucocorticosteroid treatment. In separate experiments treatment of alveolar macrophages with 10(-7) or 10(-6) M budesonide overnight in vitro did not affect their superoxide radical or PGE2 generation but significantly blocked LTB4 release. These data indicate that inhaled gluco-corticosteroid treatment may affect synthesis or release (or both) of ACE and fibronectin by alveolar macrophages from healthy smokers whereas other functions of these cells, such as the generation of reactive oxygen derived products ex vivo, are only marginally affected.

Evaluation and management of scleroderma lung disease using bronchoalveolar lavage

PURPOSE

Bronchoalveolar lavage (BAL) was performed in 43 nonsmoking patients with scleroderma (systemic sclerosis) to determine the frequency of alveolitis, the status of BAL findings over time, and the relationship of such findings to pulmonary status initially and at follow-up.

PATIENTS AND METHODS

Forty-three nonsmoking patients with systemic sclerosis underwent extensive pulmonary evaluation including pulmonary function tests, chest radiographs, and BAL with analysis of cells, IgG, albumin, immune complexes, and fibronectin.

RESULTS

Alveolitis was detected on initial BAL evaluation in 21 patients (49%). Alveolitis was characterized by hypercellular lavage fluid, due to an absolute increase in alveolar macrophages and due to an increase in both the absolute number and percentage of granulocytes (neutrophils and eosinophils). Patients with systemic sclerosis had significantly higher levels of IgG and immune complexes in BAL fluid than did control subjects, and alveolar macrophages from patients with systemic sclerosis released higher amounts of fibronectin in vitro. In serial studies, alveolitis was found to persist. Patients with alveolitis had greater dyspnea than patients without alveolitis (p = 0.02), and they had greater reductions in lung volumes and carbon monoxide diffusing capacity (DLCO) (p = 0.004). Furthermore, patients with persistent alveolitis had significantly greater reductions in pulmonary function over time than patients without alveolitis (forced vital capacity [FVC]: -0.69 L versus -0.05 L, p less than 0.001; DLCO: -2.94 mL/minute/mm Hg versus +0.16 mL/minute/mm Hg, p = 0.03). BAL was used to select patients with alveolitis and at risk of pulmonary deterioration, and treatment was instituted with cyclophosphamide and prednisone, resulting in significant improvement in dyspnea (p less than 0.001) and the rate of change of FVC (p = 0.02) and DLCO (p less than 0.001).

CONCLUSION

We conclude that alveolitis occurs frequently in systemic sclerosis and that BAL is useful in identifying such patients who are at risk for a further decline in pulmonary status. Preliminary observations suggest that treatment of patients with active alveolitis may result in improvement in pulmonary status.

Intrinsic PEEP on static pressure-volume curves

The static pressure volume (PV) curve of the total respiratory system is a well established method to assess pulmonary mechanics during respiratory failure. We have tested the impact of auto-PEEP on the PV curve determination in 16 COPD patients. An isovolumic pressure increment (IPI) was found at the beginning of the curve and a close correlation between IPI and auto-PEEP level (r = 0.962) p less than 0.001) was observed. The regression equation was not significantly different from the identity line. We conclude that the appearance of IPI in PV curves is largely determined by auto-PEEP and it is a good estimate of the existing auto PEEP level.

Measurement of effective elastance of the total respiratory system in ventilated patients by a computed method. Comparison with the static method

We have studied 28 patients mechanically ventilated for acute respiratory failure at different levels of externally applied positive end-expiratory pressure (PEEPe). We describe and compare a computed method of measuring "effective" elastance of the total respiratory system (Ers,eff) with the static values of elastance of the total respiratory system (Ers,st), obtained with the end-inflation occlusion technique. Ers,eff was computed by an original device (Heres, R.P.A., Belgium), also the effective resistance of the total respiratory system was calculated. At zero end-expiratory pressure set by the ventilator (ZEEP). Ers,eff averaged 29.5 +/- 13.5 cm H2O x L-1 while Ers,st non-corrected for intrinsic PEEP (PEEPi) averaged 36.4 +/- 15.1 cm H2O x L-1 and Ers,st corrected for PEEPi averaged 28.2 +/- 13.4 cm H2O x L-1. The small difference between Ers,eff and Ers,st corrected for PEEPi was statistically significant and these two values were highly correlated (r = 0.98). This significant difference disappeared rapidly with PEEPe and probably reflects a frequency-dependance due to pendelluft. We also observed that PEEPi was present in 21 of 27 patients at ZEEP. Our results also indicate that low levels of PEEP may improve Ers in hyperinflated COPD patients, without inducing further hyperinflation. In conclusion, values of Ers,eff are very similar to static values corrected for PEEPi and permit an accurate and rapid approach to the management of ventilated patients.

Lung disease associated with progressive systemic sclerosis. Assessment of interlobar variation by bronchoalveolar lavage and comparison with noninvasive evaluation of disease activity

Progressive systemic sclerosis (PSS), or scleroderma, is a disease of unknown etiology that involves many organ systems, including the lungs. The interstitial lung disease of systemic sclerosis is becoming an increasing cause of morbidity and mortality. This process has been previously evaluated with single-site bronchoalveolar lavage (BAL), gallium scanning, pulmonary function testing, and, occasionally, by open lung biopsy. As BAL has been shown to correlate well with open lung biopsy in systemic sclerosis, we sought to determine if single-site BAL accurately reflects alveolitis in a second site in the lung, and if BAL results correlate with other noninvasive tests of lung inflammation: gallium uptake, chest radiography, or arterial blood gas analysis. We performed 17 studies in 13 patients with scleroderma and found no significant lobar differences in lavage results or gallium scanning. By our criteria for normal versus active alveolitis, only two of 17 patient lavages would have been classified as normal by one side and abnormal by the other side. Although percent gallium uptake was equal bilaterally and supported the concept of alveolitis uniformity, gallium uptake intensity did not correlate with activity as measured by BAL. Furthermore, chest radiograph and arterial blood gas analysis did not correlate with BAL results or gallium scanning. We believe these data support the suitability of single-site lavage in the investigation of systemic-sclerosis-associated alveolitis and diminish the importance of gallium scanning in the investigation of systemic sclerosis pulmonary disease.

Macrophages and polymorphonuclear neutrophils in lung defense and injury

Phagocytes, in particular macrophages and PMN, are now recognized as major components of inflammatory and immunologic reactions in the lung. Normally, macrophages represent the majority of phagocytes in the lower respiratory tract. These lung macrophages are morphologically and functionally heterogenous and include alveolar, interstitial, intravascular, and airway macrophages, each with characteristic morphologic and functional features. Through the presence of surface receptors for numerous ligands and through their large number of secretory products, lung macrophages can respond to environmental factors and account for most of the clearance of microparticles and microorganisms in the distal airways and the alveolar spaces. In addition, macrophages also play an important role in inflammatory processes through the release of oxygen radicals and proteolytic enzymes. Through the release of several cytokines, i.e., growth-promoting and inhibiting factors, lung macrophages may also influence both matrix damage and repair processes. Macrophages can also contribute to the alveolitis by recruitment of inflammatory and immune cells. This latter contribution is best demonstrated in migration movement of PMN. The normal distal airways generally contain a small number of PMN, but the pulmonary vascular bed represents a large reservoir of PMN. Some of them are in intimate contact with the endothelium, forming the so-called marginating pool of PMN. Because the capillary lumen is separated only from the alveolar space by a monolayer of endothelial and epithelial cells on each side of a thin interstitial matrix, it is likely that some inhibitory mechanism exists to prevent PMN from migrating towards the alveolar space. Such inhibitors of PMN migration are present both in serum and in the alveolar space, some being released by alveolar macrophages. However, alveolar macrophages can also secrete factors called chemotaxins that attract PMN to the airways, and this supports a central role for alveolar macrophages in the regulation of PMN traffic in the lungs. Thus, secretory products of alveolar macrophages are part of the regulatory mechanisms of PMN mobility and adherence that appears to be crucial in the initiation of some inflammatory reactions. The contribution of phagocytes to the defense against infection and tumor has been documented mostly in vitro. Thus, both oxygen radicals, in particular hydroxyl radicals and proteases such as lysozyme, are potent bactericidal agents. That phagocytes are also important defenders of the lungs in vivo is best supported by the observations in immunodeficient patients and animal models.(ABSTRACT TRUNCATED AT 400 WORDS)

TGF-beta enhances the production of hyaluronan in human lung but not in skin fibroblasts

Transforming growth factor-beta (TGF-beta) enhances the production of extracellular matrix components, such as type I and type III collagen, fibronectin, proteoglycans, in various cell types. The effect on hyaluronan synthesis in relation to proteoglycan synthesis has not been investigated. Human lung or skin fibroblast cultures were treated with TGF-beta in serum-free medium for various periods of time. 35SO4 or [3H]glucosamine was then added to the cultures in the absence of TGF-beta for up to 48 h. Hyaluronan and proteoglycans were isolated by ion-exchange chromatography and quantitated. TGF-beta induced a three- to fourfold increase in hyaluronan production by lung cells but had no effect on skin fibroblasts. In contrast, proteoglycan synthesis was enhanced in both cell types, although skin fibroblasts responded at lower concentrations of TGF-beta. Increased accumulation of hyaluronan was noted only in the cell medium, whereas proteoglycan accumulation was observed both in the medium and in the cell layer. The ED50 for TGF-beta on hyaluronan accumulation in lung cells was the same as that for proteoglycan accumulation, i.e., 40 pM. In skin fibroblasts the ED50 was considerably lower (4 pM). The induction time needed to attain full effect of TGF-beta was 6 h for both hyaluronan and proteoglycan synthesis. These results indicate that TGF-beta has tissue-specific effects on matrix production which may be of importance for control of cell proliferation in various disease states.

Assessment of induced bronchoconstriction in anesthetized cats by the end-inflation occlusion method

Airway occlusion during constant flow inflation allows rapid determination of frequency-dependence of pulmonary resistance by estimating its extreme values: RL,max (zero frequency) and RL,min (high frequency). RL,max represents the maximum resistance value that can be obtained with the prevailing time constant inequalities and stress relaxation, while RL,min represents the resistance that would be obtained in the absence of time constant inequalities and stress relaxation. In 5 anesthetized, tracheostomized, paralyzed, and artificially ventilated cats, RL,min, RL,max, and static pulmonary elastance (EL,st) have been measured following airway occlusion at the end of constant flow tidal inflations. Measurements were made before and during continuous infusion of increasing doses of serotonin (10-100 micrograms/kg/min IV). The development of intrinsic positive end-expiratory pressure (PEEPi) was also assessed. Cats varied greatly in their responsiveness to serotonin, but RL,min, RL,max, and EL,st increased and PEEPi developed in all cats. Increases in RL,max did not always parallel increases in RL,min but were similar to those in EL,st, suggesting that altered viscoelastic properties of the lung contributed to the increases in RL,max. We conclude that time-constant inequalities, changes in the lung periphery, and hyperinflation probably all contribute to the observed increases in RL,max and will influence conventional methods of measuring RL. Measuring RL,min potentially provides a better method for assessing the reduction in caliber of the conducting airways in isolation.

Pulmonary involvement in systemic sclerosis: the detection of early changes by thin section CT scan, bronchoalveolar lavage and 99mTc-DTPA clearance

Systemic sclerosis is frequently complicated by fibrosing alveolitis although clinical and radiological abnormalities are not usually apparent until the lung disease is well established. The aim of this study was to investigate pulmonary involvement in systemic sclerosis by thin section CT scan, bronchoalveolar lavage (BAL) and 99mTc-DTPA clearance studies, and assess the value of these tests in defining pulmonary abnormalities in patients with a normal chest radiograph. Patients were divided into those with an abnormal chest radiograph (Group I, n = 14) and those with a normal chest radiograph (Group II, n = 16). CT scans were abnormal in all patients in Group I and 7 of 16 (44%) in Group II. BAL inflammatory cell counts were raised in all 12 (100%) patients studied in Group I and 11 of 15 (73%) in Group II. There was no difference in the type of inflammatory cells observed between the two groups. 99mTc-DTPA clearance was faster than normal controls in ten of 14 patients (71%) in Group I and seven of 15 (47%) in Group II and correlated with carbon monoxide transfer factor (P less than 0.05). Lung biopsies were performed on nine patients in Group I and three in Group II all of whom had abnormal CT scans. Fibrosing alveolitis was confirmed in every case. Group II biopsies could not be distinguished from Group I biopsies; both showed fibrosis as well as inflammation suggesting that pulmonary fibrosis is an early abnormality in systemic sclerosis. Our results indicate that CT scans, BAL and 99mTc-DTPA are frequently abnormal in asymptomatic patients with systemic sclerosis who have normal chest radiographs. When the CT scan is normal abnormalities of BAL and/or 99mTc-DTPA (99mTechnetium diethylenetriamine pentacetate) clearance may indicate lung disease at a still earlier stage. This observation requires further investigation.

Pressure support ventilation (PSV) reverses hyperinflation induced isorhythmic A-V dissociation

We report a case of hyperinflation induced isorythmic atrio-ventricular dissociation with circulatory failure in a patient with chronic obstructive pulmonary disease. The arrythmia was successfully treated by applying "pressure support ventilation" (PSV: 20 cmH2O) which, by decreasing the respiratory rate and increasing the expiratory time reduced the level of auto-PEEP. In order to explain this result the Authors recorded, in the same patient, the level of auto-PEEP and delta FRC obtained with Intermittent Positive Pressure Ventilation (IPPV), Intermittent Mandatory Ventilation (IMV) and PSV at the same gas exchange values. PSV showed a dramatic reduction of both these parameters. (Auto-PEEP: IPPV 12 cmH2O, IMV 17 cmH2O, PSV 7 cmH2O).

Spontaneous production of fibronectin by alveolar macrophages in patients with scleroderma

Interstitial pulmonary fibrosis is a common manifestation of systemic sclerosis (SSc) and is a pathologic feature shared by a variety of other diseases. In these other disease processes, the glycoprotein fibronectin (FN) has been shown to be released by the alveolar macrophage, and is thus implicated in the development of fibrosis. We therefore studied the release of FN by alveolar macrophages obtained by bronchoalveolar lavage of 17 patients with SSc and 14 controls. We found that SSc alveolar macrophages released significantly more FN than did those of controls. Furthermore, the level of FN correlated positively with the level of inflammation determined by cellular analysis of lavage fluid and negatively with carbon monoxide diffusing capacity. FN may therefore play a role in the development of lung fibrosis in SSc and may be a marker of alveolitis.

Measurement of the flow-resistive properties of double-lumen bronchial tubes in vitro

This study measures the resistance to gas flow of different double-lumen bronchial tubes used for separate ventilation of each lung in critically ill patients. Different-sized Robertshaw and Carlens' tubes were studied, as well as a new device that consisted of a cuffed bronchial catheter introduced through a standard tracheal tube. The pressure-flow relationship was curvilinear in all cases. Robertshaw and Carlens' tubes were generally found to have bronchial and tracheal channels with almost similar resistance and offered total resistances similar to those of 7.0-8.0 mm internal diameter tracheal tubes. The new device had a higher resistance than others of equal external diameter. This must be taken into account when its use is recommended for prolonged respiratory support.

Isolation and antigenic identification of hamster lung interstitial macrophages

Lung interstitial macrophages (IMs) are a large, distinctive population of cells with important proliferative capacities. Characterization of their role in health and disease has been hampered by inadequate methods to separate interstitial from residual alveolar macrophages (AMs) in preparations of individual mononuclear cells from lung tissue. In this study, a specific cell-surface antigen (HAM1) present on more than 90% of hamster AMs, but not expressed by hamster IMs, was used to distinguish these populations. After collagenase digestion of lung tissue slices from exhaustively lavaged and perfused hamster lungs, mononuclear phagocytes were isolated by density gradient centrifugation. The mean yield of lung digest macrophages (3.9 +/- 1.9 (SD) x 10(6] was comparable to the yield of lavaged AMs (4.2 +/- 1.9 x 10(6]. The proliferative capacity of lavaged AMs, blood monocytes, and lung digest macrophages was compared using a soft-agar colony-forming unit (CFU) assay. Both lung digest macrophages and blood monocytes had significantly more CFUs (68.7 +/- 2.6 and 53.5 +/- 8.4 CFU/10(3) cells [mean +/- SEM], respectively) than did AMs (16.5 +/- 1.7) (p less than 0.01). To further define the composition of the lung digest macrophage population, flow cytometric analysis of fixed cells from six experiments was performed using a mouse monoclonal antibody specific for the HAM1 antigen found only on AMs. The lung digest macrophage population consisted of both antigen-negative IMs (78.2% +/- 3.7% [SEM]; n = 6) and antigen-positive, residual AMs (21.8% +/- 3.7%). Morphometric counts confirmed that substantial numbers of AMs are left behind after lavage and contribute to macrophages obtained from lung tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory compliance and resistance in mechanically ventilated patients with acute respiratory failure

The purpose of this study was noninvasive assessment of respiratory compliance and resistance in mechanically ventilated patients with acute respiratory failure (ARF). To this end, flow, change in lung volume, and airway pressure were measured at the proximal tip of the endotracheal tubes in twenty nine critically ill unselected patients. Eleven had acute exacerbation of chronic obstructive pulmonary disease (COPD), 8 had adult respiratory distress syndrome (ARDS) and 10 had ARF of various etiologies. Static compliance (Cst,rs), 'intrinsic' PEEP (PEEPi), as well as minimum and maximum resistance (Rrs,min and Rrs,max, respectively) were obtained with end-inspiratory and end-expiratory airway occlusions. We found that: (1) PEEPi was present in all patients with COPD (up to 11.4 cmH2O) and it was not uncommon in patients with ARF without history of chronic airway disease (up to 4.1 cmH2O). (2) Without correction for PEEPi average Cst,rs was not significantly different between ARDS and COPD patients, whereas the average corrected compliance was significantly lower in ARDS patients. (3) Substantial frequency-dependence of resistance was exhibited not only by COPD patients, but also by ARDS patients.

Systemic scleroderma. Clinical and pathophysiologic aspects

Systemic scleroderma is a generalized disease of connective tissue involving mainly the skin, the gastrointestinal tract, the lungs, the heart, and the kidneys. It can be present in different forms, of which acroscleroderma, with limited cutaneous and extracutaneous involvement, and diffuse scleroderma within a more rapid progression are most characteristic. Circulating antibodies against antinucleolar antigens are present in most patients with systemic scleroderma. They are helpful for establishing a classification and for determining the prognosis of the disease; their involvement in the pathogenesis, however, is still unclear. Alterations of the blood vessels and induction of fibroblasts by potent mediators are thought to play an important role in the early phase of scleroderma. Therefore early diagnosis is required, which then can initiate vasoactive therapy. In patients with systemic scleroderma, who also suffer from additional myositis, interstitial lung diseases, or arthritis, anti-inflammatory treatment with prednisolone and azathioprine is suggested. Development and progression of fibrosis cannot yet be influenced sufficiently. Only D-penicillamine affecting cross-linking of collagen has been widely used in scleroderma and has some beneficial effect.

Studies on anti-granulocyte and anti-platelet antibodies in patients with systemic sclerosis. Chemotaxis, phagocytosis and opsonized effect of PSS sera on normal granulocytes

Autoantibodies may play a part in the pathogenesis of progressive systemic sclerosis (PSS). Anti-granulocyte antibodies have already been demonstrated in the sera of patients with PSS. In our study, anti-granulocyte antibodies were investigated by ELISA (enzyme linked immunosorbent assay) and cytotoxic tests. These antibodies were found in 18.4% of 38 patients. All the positive sera showed cold- and/or warm-reacting granulocytotoxic activity. No connection with granulocytopenia was found. The effect of patients' sera on normal granulocyte functions was also studied. Chemotaxis and binding of EA cells were inhibited independently of the presence of anti-granulocyte antibodies. Yeast phagocytosis and opsonized yeast phagocytosis were definitely reduced by sera containing anti-granulocyte antibodies. Anti-platelet autoantibodies were detected in 23.9% of the patients' sera, but no thrombocytopenia was found.

Activated alveolar macrophages in subclinical pulmonary inflammation in collagen vascular diseases

A study was initiated to determine whether alveolar macrophages from patients with collagen vascular diseases but free of pulmonary symptoms were spontaneously activated and whether they released various mediators related to the pathogenesis of pulmonary fibrosis. Alveolar macrophages obtained by bronchoalveolar lavage from 32 patients with proved collagen vascular disease but no evidence of lung disease were compared with those from 10 patients with collagen vascular disease with interstitial lung disease (CVD-ILD) and from 10 healthy controls. The total number of alveolar macrophages did not differ between patients with collagen vascular disease and controls but were substantially increased in the CVD-ILD group. Alveolar macrophages from 31 of the 32 patients with collagen vascular disease and from all 10 in the CVD-ILD group had at least one criterion of activation. Neutrophil chemotactic activity was detected in supernatants from alveolar macrophage culture in 23 of the 32 patients with collagen vascular disease and from nine of the 10 in the CVD-ILD group; fibronectin secretion by alveolar macrophages was increased in 12 of the 32 patients with collagen vascular disease and in nine of the 10 in the CVD-ILD group. Furthermore, alveolar macrophages from 20 of the 32 patients with collagen vascular disease and four of the 10 CVD-ILD patients spontaneously released increased amounts of superoxide anion. Thus alveolar macrophages were spontaneously activated in a high proportion of patients with collagen vascular disease.

Subclinical lung inflammation in primary Sjögren's syndrome. Relationship between bronchoalveolar lavage cellular analysis findings and characteristics of the disease

To directly evaluate whether a subclinical alveolar inflammation is associated with primary Sjögren's syndrome (SS), we evaluated the distribution of cells obtained by bronchoalveolar lavage (BAL) from the lower respiratory tract in 29 patients who had primary SS, but who were free of clinical pulmonary symptoms and had normal findings on chest roentgenograms. There was no difference in total cell counts of specimens from patients versus those of controls. An abnormal differential cell count was noted in 16 patients (55%). Two patterns of alveolitis were observed: a pure lymphocyte alveolitis (greater than 18% lymphocytes, present in 11 patients) and a neutrophil alveolitis (greater than 4% neutrophils, present in 5 patients). There was associated lymphocytosis in 4 of the patients with neutrophil alveolitis. All patients had normal results on pulmonary function tests. Patients with abnormal BAL findings showed clinical and biologic indexes of more severe disease than did those with normal BAL results, as demonstrated by greater extraglandular extension of the disease, higher mean values of serum gamma globulins and serum beta2-microglobulin, and higher prevalence of rheumatoid factor and of antinuclear antibody. Thus, our data demonstrate that BAL permitted the detection of subclinical inflammatory alveolitis in 55% of our patients with primary SS. A long-term followup is required to determine whether these patients will develop obvious pulmonary involvement.

Measurement of respiratory mechanics using the Siemens Servo Ventilator 900C

The interrupter technique involves measuring the pressure changes at the airway opening during sudden cessation of flow and has been advocated for monitoring respiratory mechanics in artificially ventilated patients. The Siemens Servo Ventilator 900C has the ability to make airway occlusions without interrupting the patient's respiratory support. This study was performed to determine the suitability of the end-inspiratory occlusion facility of the ventilator for interrupter measurements of respiratory resistance and compliance. Measurements were made in a physical model of the respiratory system consisting of two parallel compartments, whose individual resistances and elastances were independently determined. The accuracy of the resistance measurements made using the ventilator were found to be dependent on the inspiratory flow. With an inspiratory flow of 100 ml/s, the resistance of the system could be measured to within 18% of the true value, and the static compliance could be measured to within 26% of the true value. Much of the error in these determinations was due to the finite closure time of the valve in the ventilator, and to the compliance of the gas in the tubing connecting the ventilator with the model. We conclude that the Siemens Servo Ventilator 900C can be used to conveniently obtain estimates of resistance and compliance in ventilated patients.

Severe spirometric defects in systemic lupus erythematosus. A possible role for bronchoalveolar lavage and gallium scanning

Two patients with systemic lupus erythematosus (SLE) developed progressive chronic pulmonary disease. Pulmonary bronchoalveolar lavage (BAL) and Gallium-67 scanning were performed and were consistent with alveolitis. In one patient, an open lung biopsy was performed and showed the presence of several immunoreactants as well as interstitial pneumonitis. Although mild pulmonary function abnormalities are common in SLE, some patients such as the two described in this report develop progressive and incapacitating pulmonary impairment. The need for developing standardized indices of pulmonary inflammation such as BAL and gallium scanning for the purposes of diagnosis, prognostication, and monitoring treatment responses in systemic lupus erythematosus is stressed.

Polymorphonuclear neutrophil function in systemic sclerosis

In vitro functions of polymorphonuclear (PMN) neutrophils were studied in 20 patients with progressive systemic sclerosis (PSS). An increase in the basal chemiluminescence (CL) activity of peripheral blood PMNs was found, suggesting that these cells had been preactivated in vivo. Patients with more extensive skin disease or signs of disease progression tended to have higher basal CL values. Active oxygen products during the respiratory burst may increase the extent of inflammatory and fibrotic processes and could be involved in the endothelial injury in PSS. The stimulatory capacity of CL response was normal in our study. No alterations were found in the opsonised yeast phagocytic activity of granulocytes when compared with control values. The binding of erythrocyte-antibody particles was found also to be normal. A depressed chemotactic activity of PMN cells against zymosan activated serum was also shown. The cause of the decreased chemotaxis of PMNs remains to be elucidated.

Non-invasive measurement of respiratory mechanics in ICU patients

Recent methods developed for non-invasive determination of the mechanical properties of the respiratory system have been reviewed. These methods can provide valuable on-line information in patients mechanically ventilated in the intensive care unit setting. More extensive use of such methods should help to provide a better understanding of the physiopathologic processes and adaptive mechanisms present in patients who require mechanical ventilation.

Early cellular events in pulmonary fibrosis

In this review we have surveyed recent investigations of early cellular events in pulmonary fibrosis both in animal models and in human diseases. Analysis of the interactions of the numerous cell types in the lung following injury is an almost overwhelmingly complex enterprise. In the animal models experimental design has a profound effect on results, making it difficult to compare studies when species, fibrogenic agent, dose, route of exposure, schedule of administration, time course, and analytical methods may not be equivalent. In human diseases we are rarely able to obtain data at precisely the same time point in the course of the disease even among patients in the same study, and possible confounding variables present are legion. Transcending these difficulties for the moment, can we draw any conclusions from our current knowledge of early cellular interactions in pulmonary fibrosis? What is striking is not that there are so many agents that can potentially induce pulmonary fibrosis, but that the lung has such capabilities for recovery. Although the major effector cells may all initially participate in damaging the lung and initiating fibrosis, there is evidence that they may also have the capacity to participate in subsequent repair. Macrophages may initially recruit fibroblasts and stimulate them to proliferate, only to suppress them subsequently. Macrophage production of prostaglandins can lead to suppression of macrophage, neutrophil and lymphocyte responses, thus attenuating tissue injury and the development of fibrosis. Neutrophils may initially release toxic metabolites and enzymes that damage parenchyma. However, there is evidence that they may later play a role in attenuating fibrosis, perhaps through collagenase secretion, or through as yet unknown mechanisms. Lymphocytes may initially participate in a number of damaging ways by secreting chemoattractants for other cells and participating in destructive autoimmune processes. However, there is evidence that subpopulations of T cells may dramatically shift during the course of fibrosis, leading to attenuation of the process. It may thus be useful to consider irreversible pulmonary fibrosis as the end result of a process in which the balance of normal injury/repair mechanisms is disrupted. There is clearly no single "fibrogenic event." Rather, there seem to be a number of places where disruption of balance/repair processes may begin. In diseases of unknown etiology such as sarcoidosis or IPF, loss of control may occur at the genetic level, leading to the destructive alveolitis that is the apparent precursor of fibrosis.(ABSTRACT TRUNCATED AT 400 WORDS)