Chest roentgenographic abnormalities in IL-2 recipients. Incidence and correlation with clinical parameters.

The chest roentgenograms of 54 patients receiving high dose interleukin-2 with or without lymphokine-activated killer cell therapy for advanced cancer were retrospectively reviewed. Thirty-nine patients (72 percent) developed chest roentgenographic abnormalities consisting of pleural effusions, 28 (52 percent); diffuse infiltrates (pulmonary edema), 22 (41 percent); and focal infiltrates, 12 (22 percent). These abnormalities resolved in 30 of 39 (77 percent) patients by four weeks after therapy. Simple pleural effusions were the only residual roentgenographic abnormalities seen and were present primarily in patients receiving IL-2 by bolus intravenous injection (8 of 28) (29 percent) as compared to continuous intravenous infusion (1 of 24) (4 percent) (p = 0.03). Only roentgenographic evidence of pulmonary edema appeared to correlate with the degree of clinical pulmonary toxicity (p = 0.001). The development of chest roentgenographic abnormalities correlated with the administration of IL-2 solely by bolus intravenous injection (p = 0.04), a pretreatment FEV1 of less than 3 L (p = 0.04), and treatment associated bacteremia (p = 0.09), but not with prior therapy, the presence of pulmonary metastases or the degree of systemic capillary leak as measured by percentage of weight gain during therapy. Although the roentgenographic abnormalities did not relate to the number of LAK cells received, two patients developed sudden onset of dyspnea and chest roentgenographic evidence of pulmonary edema shortly after the first LAK cell administration, implying that a direct cause-and-effect relationship exists in some patients. Possible mechanisms for these IL-2 related chest roentgenographic abnormalities and pulmonary toxicity in general are discussed.     

Tomographic study of the inflection points of the pressure-volume curve in acute lung injury

The inflection points of the pressure-volume curve have been used for setting mechanical ventilation in patients with acute lung injury. However, the lung status at these points has never been specifically addressed. In 12 patients with early lung injury we traced both limbs of the pressure-volume curve by means of a stepwise change in airway pressure, and a computed tomography (CT) scan slice was obtained for every pressure level. Although aeration (increase in normally aerated lung) and recruitment (decrease in nonaerated lung) were parallel and continuous along the pressure axis during inflation, loss of aeration and derecruitment were only significant at pressures below the point of maximum curvature on the deflation limb of the pressure-volume curve. This point was related to a higher amount of normally aerated tissue and a lower amount of nonaerated tissue when compared with the lower inflection point on both limbs of the curve. Aeration at the inflection points was similar in lung injury from pulmonary or extrapulmonary origin. There were no significant changes in hyperinflated lung tissue. These results support the use of the deflation limb of the pressure-volume curve for positive end-expiratory pressure setting in patients with acute lung injury.     

Pressure-volume curve of total respiratory system in acute respiratory failure. Computed tomographic scan study

To investigate the relationship between lung anatomy and pulmonary mechanics in acute respiratory failure (ARF), 20 patients with ARF underwent computerized tomography (CT) at 3 levels of positive end-expiratory pressure (PEEP) (5, 10, and 15 cm H2O). The static pressure-volume curve of the total respiratory system and the lung volumes (helium dilution method) were also measured. By knowing the lung volumes and analyzing the CT number frequency distribution, a quantitative estimate of normally aerated, poorly aerated, and nonaerated lung tissue was obtained at each level of PEEP. The recruitment was defined as the percent increase of normally aerated tissue from 5 to 15 cm H2O. We found that the different compliances (starting compliance, inflation compliance, and deflation compliance) were correlated only with the amount of normally aerated tissue present in the range of pressures explored by a given compliance (5 cm H2O for starting compliance and 15 cm H2O for inflation and deflation compliances). No relationship was found between the compliances and the poorly aerated and nonaerated tissue. The specific compliance was in the normal range, whereas the amount of recruitment was related to the ratio of inflation compliance to starting compliance. Our data suggest that (1) the pressure-volume curve parameters in ARF investigate only the residual healthy zones of the lung and do not directly estimate the "amount" of disease (poorly or nonaerated tissue), (2) the pressure-volume curve may allow an estimate of the anatomic recruitment, and (3) the residual normally aerated zones of the ARF lung seem to maintain a normal intrinsic elasticity.     

Computed tomography assessment of positive end-expiratory pressure-induced alveolar recruitment in patients with acute respiratory distress syndrome

Computed tomography (CT) assessment of positive end-expiratory pressure (PEEP)-induced alveolar recruitment is classically achieved by quantifying the decrease in nonaerated lung parenchyma on a single juxtadiaphragmatic section (Gattinoni's method). This approach ignores the alveolar recruitment occurring in poorly aerated lung areas and may not reflect the alveolar recruitment of the entire lung. This study describes a new CT method in which PEEP-induced alveolar recruitment is computed as the volume of gas penetrating in poorly and nonaerated lung regions following PEEP. In 16 patients with acute respiratory distress syndrome a thoracic spiral CT scan was performed in ZEEP and PEEP 15 cm H(2)O. According to the new method, PEEP induced a 119% increase in functional residual capacity (FRC). PEEP-induced alveolar recruitment was 499 +/- 279 ml whereas distension and overdistension of previously aerated lung areas were 395 +/- 382 ml and 28 +/- 6 ml, respectively. The alveolar recruitment according to Gattinoni's method was 26 +/- 24 g and no correlation was found between both methods. A significant correlation was found between PEEP-induced alveolar recruitment and increase in Pa(O(2)) only when recruitment was assessed by the new method (Rho = 0.76, p = 0.003), suggesting that it may be more accurate than Gattinoni's method.     

Imaging studies in emphysema

Definitions of types of emphysema within the framework of chronic obstructive pulmonary disease are given. The classic findings on the chest radiograph are described, and the advances in sensitivity and specificity achieved with computed tomography (CT) scanning are noted. The "density mask" and the "percentile point" measurements rely on the densitometric property of X-rays, but the scan also shows the severity and distribution of low-attenuation regions that usually represent pathologic emphysema. The alteration of absolute density with changes in lung inflation, CT slice thickness, collimation, and reconstruction algorithm make comparison between CT scans and across studies more difficult. Nevertheless, quantitative CT has superseded subjective scoring of scan appearance by readers as a sensitive way to measure emphysema.     

Effects of short-term pressure-controlled ventilation on gas exchange,airway pressures,and gas distribution in patients with acute lung injury/ARDS: comparison with volume-controlled ventilation

STUDY OBJECTIVES: The potential clinical benefits of pressure-controlled ventilation (PCV) over volume-controlled ventilation (VCV) in patients with acute lung injury (ALI) or ARDS still remain debated. We compared PCV with VCV in patients with ALI/ARDS with respect to the following physiologic end points: (1) gas exchange and airway pressures, and (2) CT scan intrapulmonary gas distribution at end-expiration. DESIGN: Prospective, observational study. SETTING: A multidisciplinary ICU in a nonuniversity, acute-care hospital. PATIENTS: Ten patients with ALI or ARDS (9 men and 1 woman; age range, 17 to 80 years). INTERVENTIONS: Sequential ventilation in PCV and VCV with a constant inspiratory/expiratory ratio, tidal volume, respiratory rate, and total positive end-expiratory pressure; measurement of gas exchange and airway pressures; and achievement of CT sections at lung base, hilum, and apex for the quantitative analysis of lung densities and of aerated vs nonaerated zones. RESULTS: PaO(2), PaCO(2), and PaO(2)/fraction of inspired oxygen ratio levels did not differ between PCV and VCV. Peak airway pressure (Ppeak) was significantly lower in PCV compared with VCV (26 +/- 2 cm H(2)O vs 31 +/- 2 cm H(2)O; p < 0.001; mean +/- SEM). The surface areas of the nonaerated zones as well as the total areas at each section level were unchanged in PCV compared with VCV, except at the apex level, where there was a significantly greater nonaerated area in VCV (11 +/- 2 cm(2) vs 9 +/- 2 cm(2); p < 0.05). The total mean CT number of each lung (20 lungs from 10 patients) was similar in the two modes, as were the density values at the basal and apical levels; the hilum mean CT number was - 442 +/- 28 Hounsfield units (HU) in VCV and - 430 +/- 26 HU in PCV (p < 0.005). CONCLUSIONS: These data show that PCV allows the generation of lower Ppeaks through the precise titration of the lung distending pressure, and might be applied to avoid regional overdistension by means of a more homogeneous gas distribution.     

Tidal hyperinflation during low tidal volume ventilation in acute respiratory distress syndrome.

RATIONALE: Tidal volume and plateau pressure limitation decreases mortality in acute respiratory distress syndrome. Computed tomography demonstrated a small, normally aerated compartment on the top of poorly aerated and nonaerated compartments that may be hyperinflated by tidal inflation. OBJECTIVES: We hypothesized that despite tidal volume and plateau pressure limitation, patients with a larger nonaerated compartment are exposed to tidal hyperinflation of the normally aerated compartment. MEASUREMENTS AND MAIN RESULTS: Pulmonary computed tomography at end-expiration and end-inspiration was obtained in 30 patients ventilated with a low tidal volume (6 ml/kg predicted body weight). Cluster analysis identified 20 patients in whom tidal inflation occurred largely in the normally aerated compartment (69.9 +/- 6.9%; "more protected"), and 10 patients in whom tidal inflation occurred largely within the hyperinflated compartments (63.0 +/- 12.7%; "less protected"). The nonaerated compartment was smaller and the normally aerated compartment was larger in the more protected patients than in the less protected patients (p = 0.01). Pulmonary cytokines were lower in the more protected patients than in the less protected patients (p < 0.05). Ventilator-free days were 7 +/- 8 and 1 +/- 2 d in the more protected and less protected patients, respectively (p = 0.01). Plateau pressure ranged between 25 and 26 cm H(2)O in the more protected patients and between 28 and 30 cm H(2)O in the less protected patients (p = 0.006). CONCLUSIONS: Limiting tidal volume to 6 ml/kg predicted body weight and plateau pressure to 30 cm H(2)O may not be sufficient in patients characterized by a larger nonaerated compartment.     

Initial roentgenographic manifestations of bacteriologically proven Mycobacterium tuberculosis. Typical or atypical?

Admission chest roentgenograms were reviewed of all patients diagnosed with pulmonary and extrapulmonary tuberculosis (TB) at the Medical College of Georgia--Eugene Talmadge Memorial Hospital (MCG-ETMH) during a five-year period from 1979 to 1983. Of 75 patients included, 51 had pulmonary TB, whereas 24 had extrapulmonary infection. Cavitary disease was common (28 of 51 patients with pulmonary TB). Forty-four of 51 patients with pulmonary TB had involvement of apical and/or posterior segments of the upper lobes with cavitation or infiltrates. Pleural effusion, parenchymal nodules, lymphadenopathy, and lower lung field disease were uncommon. Thirteen of 24 patients with extrapulmonary TB had abnormal admission chest roentgenograms, suggesting the possibility of Mycobacterium tuberculosis infection. Despite recent studies suggesting that TB presents with atypical roentgenographic features more commonly than reported in the past, the roentgenographic manifestations of TB in our series were typical of those previously described as pathognomonic for the disease.     

Mixed connective tissue disease-associated interstitial pneumonia complicated by pneumomediastinum during prednisolone therapy]

A 59-year-old woman was admitted to our hospital with exertional dyspnea. Linear and reticular opacities in the middle and lower fields of both lungs were observed on chest roentgenograms and chest computed tomograms (CT). The presence of anti RNP-antibody and Raynaud's phenomenon, sclerosis of the fingers, and leukopenia yielded a diagnosis of mixed connective tissue disease associated with interstitial pneumonia. The symptoms and lung involvement were alleviated after the administration of prednisolone (40 mg/day). However, the patient experienced the sudden onset of dyspnea during pulmonary function tests. A chest X-ray film disclosed mediastinal air around the left pulmonary artery, and a chest CT scan demonstrated some blebs in the left lower lung field. After tapering the dosage of prednisolone in 5 mg increments per week, the pneumomediastinum disappeared without treatment. The clinical features and laboratory data findings suggested the patient's interstitial pneumonia was associated with systemic lupus erythematosus rather than with progressive systemic sclerosis or dermatomyositis. The pneumomediastinum may have been due to the rupture of blebs secondary to interstitial pneumonia during pulmonary function tests or as a result of steroid therapy.     

Computed chest tomography in the evaluation of hemoptysis. Impact on diagnosis and treatment

The results of computed chest tomograms (CT) and chest roentgenograms (CR) were compared in 32 patients who presented with hemoptysis. The CT demonstrated roentgenographic abnormalities more often than CR (p less than 0.01), providing new diagnostic information in 15 patients (46.9 percent), and clarifying CR abnormalities in five (15.6 percent) others. In addition, CT correctly localized sources of bleeding in 23 (88.5 percent) of the 26 patients in whom a site was identified at bronchoscopy, while CR localization was correct in 17 (65.4 percent) (p less than 0.05). Despite this augmentation of roentgenographic yield, information derived from CT scans influenced the management of only six patients, did not obviate the need for bronchoscopy, and supplemented the combined diagnostic yield of CR and bronchoscopy in only two. Outcome was changed in one patient in whom CT had demonstrated an otherwise unrecognized malignant solitary pulmonary nodule. The chest roentgenogram and fiberoptic bronchoscopy provided all the information essential for diagnosis and therapeutic recommendations in 93.7 percent of these patients. Although the CT provided additional information in over one half of our patients, its overall impact on clinical management was small and does not support routine use of this imaging procedure in evaluation of hemoptysis. The possible role of chest CT in evaluating carefully selected patients with hemoptysis requires further study.     

Bronchiectasis: a cause of pulmonary symptoms in heroin addicts.

Extensive and severe bronchiectasis was found in 7 heroin-addicted individuals with pulmonary symptoms whose chest roentgenograms were not suggestive of severe airway disease. Abnormalities consisted of varicose and cylindrical alterations. Pulmonary function tests revealed airflow obstruction, decreased lung volumes, and diffusion capacity impairment. Arterial blood gas analysis demonstrated mild hypoxemia in all patients and chronic hypocapnia in 4. Serial pulmonary function tests in 2 patients revealed only modest improvement in the degree of airflow obstruction. The occurence of bronchiectasis appeared to be related to episodes of heroin-induced pulmonary edema and infection.     

Pulmonary functional impairment associated with pleural asbestos disease. Circumscribed and diffuse thickening

To define the pulmonary functional impairment associated with pleural asbestos signs (PAS), we compared 738 men with only circumscribed (plaques) or diffuse pleural thickening on chest roentgenograms but no irregular opacities by ILO pneumoconiosis criteria (1980) with 738 age-matched asbestos-exposed men without any roentgenographic signs and with 228 men unexposed to asbestos. All men were white. Spirometry and total thoracic gas volumes (TGV) were measured and expressed as percentage of predicted of white Michigan men who have been modeled for spirometric values thereby adjusting for height, age, and in current and ex-smokers for duration of smoking. Asbestos-exposed men who never smoked had reduced FEF75-85 (p less than 0.01) and increased TGV (p less than .0001) as compared with unexposed men. The 155 men with PAS who had never smoked had reduced flows (p less than .0001), FVC (p less than 0.0056), and TGV (p less than .0001) when compared with 155 age-matched asbestos-exposed men. The 325 asbestos-exposed current smokers with normal chest roentgenograms compared with unexposed smokers had reduced expiratory airflows (p less than 0.0001), reduced FEV1 (p less than 0.004), and increased TGV (p less than 0.0001). The 325 current smokers with PAS had additional air trapping that further reduced vital capacity. Thus, PAS were associated with significant pulmonary dysfunction in men who never smoked, and current and ex-smokers had additional dysfunction even after adjustment for duration of smoking.     

Inflammatory pulmonary edema and positive end-expiratory pressure: correlations between imaging and physiologic studies

The anatomic and physiologic response to positive end-expiratory pressure (PEEP) was investigated using computed tomography (CT) in patients with adult respiratory distress syndrome (ARDS). The lesions (densities) in ARDS are distributed inhomogeneously but tend to concentrate in the dependent regions. The estimated lung weight (by CT scan, quantitative analysis, and lung gas volume measured with helium dilution) is, on the average, 200% higher than expected. Changing the body position from supine to prone causes a change in the density distribution in response to gravitational forces. The main effect of PEEP is to clear the densities through alveolar anatomic recruitment. Anatomic recruitment changes the mechanical characteristics of the lung and parallels the improvement in gas exchange. The effects of PEEP on pulmonary arterial pressure appear to be related to anatomic recruitment.     

Can portable chest x-ray examination accurately diagnose lung consolidation after major abdominal surgery? A comparison with computed tomography scan.

PURPOSE: To prospectively quantify the degree of accuracy of portable chest x-ray film examination in the detection of postoperative lung consolidations. STUDY: Nineteen patients had a chest x-ray film and computed tomography (CT) scan the day before and 48 h following elective abdominal aortic replacement. RESULTS: The diagnosis of lung consolidations by x-ray film examination showed sensitivity of between 0.33 and 1.00, depending on the lung zone considered (lower at the lung bases). Specificity always was greater than 0.79. Radiologic lung volume decreased 16 percent postoperatively (p < 0.01) on average and noninflated parenchyma increased by a factor of 3 (p < 0.0001). Postoperatively, PaO2 correlated with the amount of condensed lung by CT scan (p < 0.002). CONCLUSION: In postoperative conditions, x-ray film examination is a method which presents good specificity but poor sensitivity in the diagnosis of lung consolidations.     

The correlation of subcarinal density visualized on plain chest roentgenograms with computed tomographic scans

A prospective evaluation of 212 paired chest roentgenograms and computed tomographic (CT) scans was performed to determine the predictive value of detecting subcarinal adenopathy by finding increased subcarinal density on routine roentgenograms. Based on CT criteria for subcarinal lymphadenopathy, 37 true-positive and 124 true-negative cases of subcarinal adenopathy were found in 161 patients. Evaluation of density in the subcarinal area on the routine posteroanterior (PA) chest roentgenograms in these patients demonstrated a sensitivity of 72 percent and specificity of 96 percent for the detection of adenopathy when compared with established CT criteria. False-positive and false-negative appraisals of central mediastinal density on routine roentgenograms appear to be due to the super-imposition of other masses, bullae, or lack of appropriate roentgenographic contrast. The accuracy of predicting the presence or absence of subcarinal adenopathy from routine chest roentgenograms suggests that this observation is clinically useful and should be routinely evaluated.     

The role of the chest roentgenogram in febrile neutropenic patients

In a retrospective review of patients with neutropenia and fever, we sought to determine how often roentgenograms detected pulmonary disease, especially pneumonia, not suggested by signs and symptoms. Further, we sought to determine how often therapy was changed as a result of roentgenographic findings. Overall, 41 (22%) of 187 chest roentgenograms obtained during initial febrile episodes, recurrent fevers, or persistent fevers were abnormal. While most patients had signs and symptoms suggesting the presence of pulmonary disease, 17% had roentgenographic abnormalities detected in the absence of such findings. During initial febrile episodes, therapy was not changed in response to findings on the chest roentgenogram. However, during episodes of persistent or recurrent fever, findings on chest roentgenograms led to changes in therapy in eight (61%) of 13 episodes of which six (40%) resulted in clinical improvement. Chest roentgenograms were therefore found to be an important diagnostic tool in evaluating recurrent or persistent fever in the neutropenic patient but of little use during initial febrile episodes.     

The Fleischner lecture: computed tomography of diffuse pulmonary disease

The current level of computed tomography (CT) scanner resolution is such that CT is possibly the best radiographic procedure available for viewing gross pulmonary anatomy and pathology. CT densitometry, in contrast, is of limited value in assessing diffuse lung disease because of partial volume errors created by the wide range of intrathoracic tissue densities. Anteroposterior density gradients and total mean lung density can be used advantageously in a select group of patients with suspected high-density disease. The morphologic patterns of diffuse high-density lung disease as viewed on conventional roentgenograms correlate closely with those depicted on CT images. Density measurements in normal and abnormal patients suggest that the medulla of the lung may be a reservoir zone that accommodates increased blood flow via distention and recruitment of vessels under appropriate conditions. Pulmonary diseases that cause oligemia can be identified and distinguished by their combined CT densitometric and morphologic characteristics. Combined high- and low-density disease may need total integration of plain radiographs, isotopic scans, and CT scans for proper interpretation.     

An increase of abdominal pressure increases pulmonary edema in oleic acid-induced lung injury

Increased abdominal pressure is common in intensive care unit patients. To investigate its impact on respiration and hemodynamics we applied intraabdominal pressure (aIAP) of 0 and 20 cm H(2)O (pneumoperitoneum) in seven pigs. The whole-lung computed tomography scan and a complete set of respiratory and hemodynamics variables were recorded both in healthy lung and after oleic acid (OA) injury. In healthy lung, aIAP 20 cm H(2)O significantly lowered the gas content, leaving the tissue content unchanged. In OA-injured lung at aIAP 0 cm H(2)O, the gas content significantly decreased compared with healthy lung. The excess tissue mass (edema) amounted to 30 +/- 24% of the original tissue weight (455 +/- 80 g). The edema was primarily distributed in the base regions and was not gravity dependent. Heart volume, central venous, pulmonary artery, wedge, and systemic arterial pressures significantly increased. At aIAP 20 cm H(2)O in OA-injured lung, the central venous and pulmonary artery pressures further increased. The gas content further decreased, and the excess tissue mass rose up to 103 +/- 37% (tissue weight 905 +/- 134 g), with homogeneous distribution along the cephalocaudal and sternovertebral axis. We conclude that in OA-injured lung, the increase of IAP increases the amount of edema.     

Radiological imaging in acute lung injury and acute respiratory distress syndrome

Computed tomography (CT) has been utilized to study acute respiratory distress syndrome (ARDS) since the middle 1980s, when it revealed the inhomogeneous pattern of the lung lesion. Its advantages rely on the strict correlation between CT density and the lung physical density, allowing a quantification of lung compartments with different degrees of aeration. By CT scans, ARDS lung appeared to be "small" rather than "stiff," leading to the "baby lung" concept. The regional analysis revealed that this appearance derives from an evenly distributed lung edema, which tends, because of gravitational forces, to lie predominantly in the most dependent regions, leading to alveolar collapse. New data suggest that such a "sponge lung" is made by a "core," consolidated, lung portion, from which, through an inflammatory reaction, lung edema will spread, determining the collapsed and recruitable lung portion. The amount of recruitable lung varies among ARDS patients. This knowledge is necessary for a rational positive end-expiratory pressure (PEEP) setting because the amount of tissue maintained aerated by PEEP is closely associated with the amount of recruitable lung. CT scans may also help to diagnose ARDS because CT provides a good estimate of the high-permeability lung edema, the characteristic lesion of this syndrome.     

The role of CT-scan studies for the diagnosis and therapy of acute respiratory distress syndrome

CT has provided new insights on the pathophysiology of acute respiratory distress syndrome (ARDS), demonstrating that ARDS does not affect the lung parenchyma homogeneously. These findings suggest that lung edema, as assessed by CT scan, should be included in the definition. Lung CT findings may provide a firm rationale for tailoring tidal volume during mechanical ventilation. Ideally, tidal volume should be proportional to the portion of the lung open to ventilation, as assessed by CT scan, rather than to the body weight. CT assessment of lung recruitability seems to be a prerequisite for a rational setting of positive end-expiratory pressure.