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PubMed1984

Restoration of pulmonary functions after reinflation in chronic atelectasis.

Recovery of the lungs after the reinflation of chronic atelectasis was studied experimentally using adult dogs. Obstructive absorption atelectasis was induced by banding the left main bronchus with a thin metallic plate. Tests were conducted 1 month after reinflation of the lungs. In the group of dogs which had suffered atelectasis for 3 months, static compliance and pulmonary blood flow were decreased by half at 1 month after reinflation; the conditions of reduced PO2, increased A-aDO2, and increased shunt flow rate in the affected lung persistently continued, and histological findings also showed collapse of the majority of alveoli and dilatation of the peripheral bronchioli, while macroscopically the lungs appeared to be aerated. It was therefore assumed that further aeration of the alveolar areas was impossible. The pulmonary function of the dogs within 1 month of atelectasis was restored to the same degree as that of the control group.

Animals↗
PubMed2004

Reducing atelectasis attenuates bacterial growth and translocation in experimental pneumonia.

Besides being one of the mechanisms responsible for ventilator-induced lung injury, atelectasis also seems to aggravate the course of experimental pneumonia. In this study, we examined the effect of reducing the degree of atelectasis by natural modified surfactant and/or open lung ventilation on bacterial growth and translocation in a piglet model of Group B streptococcal pneumonia. After creating surfactant deficiency by whole lung lavage, intratracheal instillation of bacteria induced severe pneumonia with bacterial translocation into the blood stream, resulting in a mortality rate of almost 80%. Treatment with 300 mg/kg of exogenous surfactant before instillation of streptococci attenuated both bacterial growth and translocation and prevented clinical deterioration. This goal was also achieved by reversing atelectasis in lavaged animals via open lung ventilation. Combining both exogenous surfactant and open lung ventilation prevented bacterial translocation completely, comparable to Group B streptococci instillation into healthy animals. We conclude that exogenous surfactant and open lung ventilation attenuate bacterial growth and translocation in experimental pneumonia and that this attenuation is at least in part mediated by a reduction in atelectasis. These findings suggest that minimizing alveolar collapse by exogenous surfactant and open lung ventilation may reduce the risk of pneumonia and subsequent sepsis in ventilated patients.

Animals↗
PubMed1991

Effects of halothane on hypoxic pulmonary vasoconstriction in canine atelectasis.

We studied the interactions of atelectasis and halothane on hypoxic pulmonary vasoconstriction using an isolated canine lobe. We divided pulmonary vascular resistance into arterial, venous, and middle segmental resistances by a vascular occlusion technique. We found that middle segmental resistance significantly increased (P less than 0.05) from 0.016 +/- 0.007 cm H2O.mL-1.min-1 during normoxic ventilation to 0.06 +/- 0.007 cm H2O.mL-1.min-1 during hypoxic ventilation. We then produced sublobar atelectasis by introducing 4.5-mm steel ball bearings into the lobar bronchus, which resulted in a significant increase (P less than 0.05) of middle segmental resistance to 0.046 +/- 0.014 cm H2O.mL-1.min-1 during normoxic ventilation and a further significant increase (P less than 0.05) to 0.084 +/- 0.02 cm H2O.mL-1.min-1 during hypoxic ventilation. Ventilation with 2.0% halothane but not 0.5% halothane prevented the increases in middle segmental resistance observed with either atelectasis or hypoxic ventilation. Values of arterial and venous segmental resistances were not similarly affected. We conclude that sublobar atelectasis increases pulmonary vascular resistance by stimulating hypoxic pulmonary vasoconstriction. Both halothane and hypoxia primarily act upon the middle vascular segment, but their effects are in opposite directions and, in the former instance, are concentration-dependent.

Analysis of Variance↗
PubMed1995

Lack of association between atelectasis and fever.

Postoperative fever occurs in many patients. If no infection is found, atelectasis, if present, may be blamed. This study of 100 postoperative cardiac surgery patients followed up from day of surgery through the second postoperative day with daily portable chest radiographs and continuous bladder thermometry was designed to look for an association between atelectasis and fever. The daily incidence of atelectasis increased from 43 to 69 to 79%. However, the incidence of fever, defined as temperature > or = 38.0 degrees C fell from 37 to 21 to 17%. When defined as temperature > or = 38.5 degrees C, the daily incidence of fever fell daily from 14 to 3 to 1%. Using chi 2 analysis, no association could be found between fever and amount of atelectasis. This contradicts common textbook dogma but agrees with previous human study and animal experiments.

Adult↗
PubMed2005

Analysis of atelectasis, ventilated, and hyperinflated lung during mechanical ventilation by dynamic CT.

STUDY OBJECTIVE: To study the dynamics of lung compartments by dynamic CT (dCT) imaging during uninterrupted pressure-controlled ventilation (PCV) and different positive end-expiratory pressure (PEEP) settings in healthy and damaged lungs. DESIGN: Experimental animal investigation. SETTING: Experimental animal facility of a university department. INTERVENTIONS: In seven anesthetized pigs, static inspiratory pressure volume curves were obtained to identify the individual lower inflection point (LIP) before and after saline solution lung lavage. During PCV, PEEP was adjusted 5 millibars (mbar) below the individually determined LIP (LIP - 5), at the LIP, and 5 mbar above the LIP (LIP + 5). MEASUREMENTS AND RESULTS: Measurements were repeated before and after induction of lung damage. Hemodynamics, arterial and mixed venous blood gases, and dCT imaging in one juxtadiaphragmatic slice (effective temporal resolution of 100 ms) were assessed during uninterrupted PCV in series of three successive respiratory cycles. The mean fractional area (FA) of the hyperinflated lung (FA-H), mean FA of ventilated lung, mean FA of poorly ventilated lung, and mean FA of nonventilated lung (FA-NV), and the change in FA of the whole lung area (DeltaFA) were compared at different PEEP settings. Calculated pulmonary shunt (Qs/Qt) was compared to FA-NV. LIP + 5 decreased the amount of atelectasis (FA-NV) and increased hyperinflation (FA-H) in healthy and injured lungs. Cyclic changes of atelectasis (DeltaFA-NV) and hyperinflation (DeltaFA-H) were observed in both healthy and injured lungs. In the injured but not in the healthy lungs, the amount of cyclic changes of atelectasis and hyperinflation were independent from the adjusted PEEP level. FA-NV correlated with the calculated Qs/Qt, with a slight overestimation (mean +/- SEM, 2.1 +/- 4.1%). CONCLUSIONS: dCT imaging allows the following: (1) the quantification of the extent of atelectasis, ventilated, poorly ventilated, and hyperinflated lung parenchyma during ongoing mechanical ventilation; (2) the detection and quantification of repeated recruitment and derecruitment, as well as hyperinflation; and (3) an estimation of Qs/Qt. dCT adds promising functional information for the respiratory treatment of early ARDS.

Animals↗
PubMed1984

Atelectasis and neuromuscular respiratory failure.

Atelectasis occurred in 17 of 20 patients treated with assisted ventilation for respiratory failure due to neuromuscular disease. A retrospective review of chest roentgenograms and medical records indicated that atelectasis occurs early in the course of respiratory failure and has a predilection for the lower lobes. Atelectasis was associated with infection and persisted despite therapy, often for more than four weeks. This study demonstrates that atelectasis in this condition still occurs frequently despite modern practices of mechanical ventilatory assistance. Infection, occurring soon after intubation, is identified as the principal cofactor.

Adolescent↗
PubMed1987

Nasal continuous positive airway pressure in atelectasis.

Nasal continuous positive airway pressure (CPAP) has been widely and safely used in the treatment of sleep disorders but has not been previously utilized for therapy of pulmonary atelectasis in adults. We observed three patients with significant atelectasis which was refractory to conventional chest physiotherapy. Bronchoscopy was not a viable therapeutic option in any patient. Therapy with continuous nasal CPAP was initiated at 10 to 15 cm H2O. The patients tolerated the therapy well and had prompt resolution of atelectasis. Nasal CPAP may be an effective modality for therapy of pulmonary atelectasis in spontaneously breathing patients, particularly when conventional therapies are not tolerated or are ineffectual.

Adult↗
PubMed1988

Phrenic nerve function and its relationship to atelectasis after coronary artery bypass surgery.

Atelectasis following coronary artery bypass surgery (CAB) occurs in the majority of patients. To determine the importance of operative variables in the development of postoperative atelectasis and the incidence of phrenic nerve injury caused by topical cold cardioplegic solution, we studied 57 patients (53 male, four female) undergoing CAB. Their mean age, +/- SD, was 58 +/- 13 years. Transcutaneous stimulation was used to evaluate phrenic nerve function preoperatively and postoperatively in 52 patients. An unequivocal paresis of the phrenic nerve was documented in five patients. In an additional 27 patients, the amplitude of the compound diaphragm action potential was reduced postoperatively. However, methodologic limitations did not allow the conclusion that this was secondary to a phrenic axonal degeneration. Discriminant analysis of intraoperative variables showed more severe atelectasis with a larger number of grafts, with a longer operative and bypass time, when the pleural space was entered, when a right atrial drain and a cardiac insulating pad were not used, and with a lower body temperature. It is concluded that phrenic paresis may occur after CAB and topical cold cardioplegia, but that other factors must explain the atelectasis found in the majority of patients.

Cardioplegic Solutions↗
PubMed1989

Rounded atelectasis. Clinical experience with 74 patients.

Rounded atelectasis is an atelectasis of a peripheral part of the lung due to pleural adhesions and fibrosis causing deformation of the lung and bending of some small bronchi. From 1970 to 1986, some 74 patients with rounded atelectasis have been seen at the Lung Department. Sixty-four of these patients had been exposed to asbestos. The lesion was secondary to a benign asbestos pleurisy in nine patients and resulted from a slowly increasing pleural fibrosis in 13 patients; in the remaining 39 patients with exposure to asbestos, rounded atelectasis was a sudden finding, with earlier roentgenograms showing only plaques or being normal. Three patients had bilateral lesions, and one had no fewer than three small rounded atelectases. All of the asbestos-exposed patients were men. Ten patients (four women and six men) had not been exposed to asbestos. Two of these cases occurred after trauma and four after a pleural exudate. One of the latter was the only one which disappeared spontaneously. The lingula was affected in 33 cases, the middle lobe in 16, the right lower lobe in 12, the left lower lobe in 11, the right upper lobe in six, and the left upper lobe (except the lingula) in one. Nine patients underwent surgery. Operation should be avoided; the typical roentgenologic and CT findings combined with negative results of bronchoscopy (and, in some cases, fine-needle biopsy) will suffice to exclude malignancy.

Adult↗
PubMed1998

Rounded atelectasis and mesothelioma.

OBJECTIVE: The purpose of this article is to report the coexistence of rounded atelectasis with malignant pleural mesothelioma as revealed by radiography and CT. CONCLUSION: Our five cases show the coexistence of rounded atelectasis and malignant mesothelioma. If rounded atelectasis is associated with a pleural effusion, a pleural mass with or without chest-wall invasion, or thickened pleura not adjacent to the rounded atelectasis, malignant mesothelioma should be strongly considered.

Aged↗
PubMedDate not supplied

Migrating lobar atelectasis of the right lung: radiologic findings in six patients.

OBJECTIVE: To describe the radiologic findings of migrating lobar atelectasis of the right lung. MATERIALS AND METHODS: Chest radiographs (n = 6) and CT scans (n = 5) of six patients with migrating lobar atelectasis of the right lung were analyzed retrospectively. The underlying diseases associated with lobar atelectasis were bronchogenic carcinoma (n = 4), bronchial tuberculosis (n = 1), and tracheobronchial amyloidosis (n = 1). RESULTS: Atelectasis involved the right upper lobe (RUL) (n = 3) and both the RUL and right middle lobe (RML) (n = 3). On supine anteroposterior radiographs (n = 5) and on an erect posteroanterior radiograph (n = 1), the atelectatic lobe(s) occupied the right upper lung zone, with a wedge shape abutting onto the right mediastinal border. On erect posteroanterior radiographs (n = 6), the heavy atelectatic lobe(s) migrated downward, forming a peri- or infrahilar area of increased opacity and obscuring the right cardiac margin. Erect lateral radiographs (n = 4) showed inferior shift of the anterosuperiorly located atelectatic lobe(s) to the anteroinferior portion of the hemithorax. CONCLUSION: Atelectatic lobe(s) can move within the hemithorax according to changes in a patient's position. This process involves the RUL or both the RUL and RML.

Amyloidosis↗
PubMed1999

[Clinical study of 8 patients with round atelectasis associated with asbestos exposure].

Matsubase town (where our hospital is located) has a history of environmental exposure to asbestos. We reviewed the clinical and radiological features of 8 patients with round atelectasis associated with asbestos exposure who had been examined at our hospital between 1988 and 1997. The subjects were followed up over a period ranging from 6 months to 10 years (mean: 54 months). Round tumors were detected in 6 of the patients by chest CT scans but not by chest X-ray films. Five of those patients underwent transbronchial lung biopsies, and 1 was examined by bronchography. Two patients had a history of pleural effusion. Seven of the patients exhibited round atelectasis in their lower lung fields. The clinical course of round atelectasis was unchanged in all patients. Although round atelectasis is sometimes suspected of being bronchial carcinoma, it can be diagnosed without thoracotomy, on the basis of the patient's medical history and a careful examination of radiological findings.

Aged↗
PubMed1999

[Computerized tomography imaging of round atelectasis. Study of a series of 21 patients].

AIM: To show and compare to literature CT findings in round atelectasis. MATERIAL AND METHODS: It is a retrospective review of the clinical and radiological files of 21 patients (17 men; 4 women; Mean age: 62), having asbestos exposure (6/21) or pleural history (13/21) and in whom the diagnosis of round atelectasis was performed from 1988 to 1998. This diagnosis was based on the presence of the classical radiological triad: round mass abutting to pleurae, converging bronchovascular markings and pleural thickening adjacent to the mass associated at a one year follow up or three years radiological and clinical follow up or the association with three minors radiological signs. RESULTS: The 25 round atelectasis, 4 bilateral, were localized in the lower lobes (22/25) or upper lobes (3/25) at right (17/25) or left (8/25) side. Minor signs were found as in literature as followed: air bronchograms and centrally indistinct margin (25/25, diffused pleural thickening or pleural plaques (19/25), acute angles with the pleura (18/25), fissures displacement (18/25), main stem bronchus displacement (13/25), calcifications within the plaque (10/25), calcifications within the mass (10/25). A mean of 6.7 signs was found for each lesion. CONCLUSION: More than the major signs of round atelectasis the air bronchogram, the centrally indistinct margin and the presence of one sign of retraction were very frequent. The mean number of signs was 6.7 for every lesion.

Adult↗
PubMed2001

Plate atelectasis: an implication of foreign body aspiration into the lower airways in two adults.

Pneumonic patches and atelectatic or bronchiectatic changes in the tributary lung distal to the bronchial foreign body are common radiographic abnormal findings in adults with foreign body aspiration into the lower airways. Nevertheless, plate (plate-like or discoid) atelectasis, a form of peripheral atelectasis, has not been reported to associate with this condition. In this report, we describe two men with the foreign body impacted in the right intermediate bronchus. In both cases, plate atelectasis was found in the base of the right lung and disappeared after successful removal of the foreign body via fiberoptic bronchoscopy. These two cases illustrate that plate atelectasis may be an implication of foreign body aspiration into the lower airways.

Aged↗
PubMed2002

[Atelectasis in the clinical picture of intrathoracic tuberculosis].

The authors examined 85 patients with intrathoracic tuberculosis in whom the tuberculous process had been complicated by tuberculosis of the bronchi with their developed obstruction and as a result of atelectasis. Then the atelectasis-affected area became fibrotic. It was found that with the developed atelectasis, there was a persistent cession of bacterial isolation occurred, closure of decay cavities in the lung tissue, resolution of fresh focal and infiltrative changes. The presence of scarring bronchial stenosis and fibrotic atelectasis suggests of a full clinical recovery from intrathoracic tuberculosis.

Adult↗
PubMed1992

[The magnetic resonance characteristics of rounded atelectasis].

Rounded atelectasis is a peculiar form of lung collapse which is well known by radiologists. Its appearance on conventional radiographs and CT is by now well recognized and widely reported. Even though these two techniques usually allow a diagnosis to be made, the MR appearance of rounded atelectasis is worth mentioning as well. This diagnostic imaging technique is widely employed, and our experience suggests that, in some cases, MR Imaging can give an important contribution to the study of this condition. We report our experience with 6 cases of rounded atelectasis in 5 patients (one patient had bilateral lesions). Five signs characteristic of rounded atelectasis were observed: some of them are seen on both conventional radiographs and CT scans, others are typical of the latter technique. All cases showed peripheral location of the lesions and the "comet tail" sign--i.e., vascular structures gently curving into the mass. These two signs are also observed on conventional radiographs and CT scans. Typical of MR imaging are the extant 3 signs: low signal in T1 and high signal in T2-weighted images in the whole of our cases; no signal from pleural thickening next to the mass in T2-weighted images, and, finally, the "kidney-like" pattern--i.e., hypointense lines converging toward the center of the mass. All these signs, which were always observed in our series, support the current etiopathogenetic hypothesis of pleural effusion as an early sign, which is reported to be followed by fibrous pleural involution which wraps atelectatic parenchyma up. On the basis of these typical MR features a correct diagnosis can usually be made even in those cases in which conventional radiography and CT do not allow a definite diagnosis.

Contrast Media↗
PubMedDate not supplied

Rigid ventilation bronchoscopy under general anesthesia for treatment of pediatric pulmonary atelectasis caused by pneumonia: A review of 33 cases.

Pediatric pulmonary atelectasis caused by pneumonia is a common disease. If the mucus plugs or secretions occlude the bronchial trees and cannot be cleaned by coughing, suctioning, or vigorous respiratory and physical therapy, is rigid ventilation bronchoscopy (V-B) effective and safe as a therapeutic procedure in such patients? We collected 33 cases of pediatric pulmonary atelectasis that were treated by rigid V-B under general anesthesia for removal of the mucus plugs or foreign bodies. During the rigid V-B with lung lavage performed by experienced bronchoscopists, the oxygen saturation was maintained in good condition. No disastrous complications were noted. Sixty-four percent (21/33) of those with pediatric pulmonary atelectasis had significant improvement in either oxygen saturation or chest radiography within 72 hours. We conclude that when the traditional treatment in pediatric pulmonary atelectasis was ineffective, rigid V-B might be an adequate and safe procedure to remove the mucus plugs and restore pulmonary function.

Anesthesia, General↗
PubMedDate not supplied

[Natural history of experimental pulmonary atelectasis in dogs with closed chest].

In order to establish an animal model of pulmonary vasoconstriction we followed the time course of intrapulmonary shunt (Qs/Qt) in a canine model of lobar atelectasis with closed chest. Ten mongrel dogs were studied. Bronchial occlusion of the right lower lobe (RLL) was performed by inflating the balloon of a Foley catheter placed through a rigid bronchoscopy. Analysis of variance was used for statistical analysis. (15 minutes) After occlusion Qs/Qt reached its maximum increasing from 8.2 +/- 3.6 to 29.7 +/- 11.7% (p less than 0.05) and PaO2 decreased from 357 +/- 49 to 100 +/- 43 mm Hg (p less than 0.05). Afterwards, there was a progressive decline of Qs/QT accompanied by an also progressive increase in PaO2. At the end of the experiment (3 hrs post atelectasis) Qs/Qt was 11.2 +/- 4.9 and PaO2 251 +/- 124 mm Hg (p less than 0.05). Pulmonary vascular resistance increased post atelectasis from 439 +/- 168 to 598 +/- 256 d.s.cm-5 (p less than 0.05). Complete atelectasis of the RLL was confirmed postmortem. As the changes in Qs/Qt and PaO2 did not parallel the change in cardiac output we conclude that the mechanism of decrease in Qs/Qt was hypoxic vasoconstriction.

Analysis of Variance↗