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PubMed1989

Sudden infant death from atelectasis due to amniotic fluid aspiration.

An infant girl, whose hands showed lobster-claw deformity, was found dead in her bed at 17 days of age. Macroscopic and microscopic examination of the lungs showed fatal atelectasis. The alveolar spaces were filled with fluid, epithelial cells, and squamous debris. These were the constituents of amniotic fluid aspirated before birth. The present case suggested that some sudden unexpected deaths in early infancy are delayed deaths caused by amniotic fluid aspiration.

Amniotic Fluid↗
PubMed2004

Atelectasis due to bronchial compression by the vertebral column.

The authors report the case of an 18-year-old woman with a multicore-minicore syndrome in acute respiratory distress. Initially, she was treated as having pneumonia, without a complete clinical response. Further investigation showed right lower lobe atelectasis associated with an extrinsic compression of the right mainstem bronchus secondary to thoracic lordoscoliosis. Therapeutic interventions involved respiratory therapy, noninvasive ventilation, cephalic traction, and orthopedic surgery, leading to clinical and functional improvement.

Adolescent↗
PubMed1992

Insufflated halothane increases venous admixture less than nitroprusside in canine atelectasis.

Although it generally is agreed that halothane is a pulmonary vasodilator, its effect on venous admixture and hypoxic pulmonary vasoconstriction are more controversial. The effects of 2.4% halothane on pulmonary vascular resistance and venous admixture were investigated in an isolated canine lobe made atelectatic. Halothane was administered by three different methods: insufflation, addition to the pulmonary artery blood through a bubble deoxygenator, or a combination of both techniques. Pulmonary vascular resistance was divided into arterial, venous, and middle segmental resistance by a vascular occlusion technique. Middle resistance increased with 3% O2 ventilation (0.0238 +/- 0.0092 cmH2O.ml-1.min-1) or after production of atelectasis (0.0225 +/- 0.0074 cmH2O.ml-1.min-1), compared to control ventilation in the nonatelectatic lung 0.01 +/- 0.0067 cmH2O.ml-1.min-1). Halothane by any delivery method variably decreased middle resistance, with increasing potency from addition of halothane through the bubble deoxygenator (0.0118 +/- 0.0047 cmH2O.ml-1.min-1) to halothane insufflation (0.0072 +/- 0.0058 cmH2O.ml-1.min-1), and finally to a combination of both techniques (0.0026 +/- 0.0041 cmH2O.ml-1.min-1). In contrast to vascular resistance, venous admixture in the atelectatic (8 +/- 5%) and nonatelectatic lobes (7 +/- 4%) was increased with halothane insufflation (11 +/- 4%), addition of halothane through the bubble deoxygenator (26 +/- 16%), and a combination of both techniques (22 +/- 13%). Compared to intravenous nitroprusside (26 +/- 12%), halothane insufflation was less potent in increasing venous admixture when total pulmonary vascular resistances were of similar magnitude (0.0526 +/- 0.0112 and 0.0484 +/- 0.0088 cmH2O.ml-1.min-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Computed tomography of rounded atelectasis.

High resolution CT of a fixed-inflated air-dried lung was obtained from a patient with rounded atelectasis. The dense periphery of the mass was shown to correspond to an invagination of the pleura, and the central lucency to slightly aerated atelectatic lung parenchyma.

Aged↗
PubMedDate not supplied

Evaluation of patients with round atelectasis using 2-[18F]-fluoro-2-deoxy-D-glucose PET.

PURPOSE: Our goal was to determine the spectrum of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) PET findings in patients with round atelectasis (RA). METHOD: All patients from 1992 to 1997 with radiologic features of RA and FDG-PET scans were evaluated. There were nine men ranging in age from 52 to 75 years (mean 65 years). All had chest radiographs and CT scans that were correlated with FDG-PET. FDG-PET was considered positive if lesion activity was greater than mediastinal activity and negative if lesion activity was the same as or less than mediastinal activity. RESULTS: Nine patients had 10 lesions, ranging in size from 1.2 to 5.0 cm (mean 3.1 cm). Lesion locations were right lower lobe (n = 5), left lower lobe (n = 4), and lingula (n = 1). All lesions were homogeneous and of soft tissue attenuation on CT. None contained air bronchograms or calcification. All had in-curving vessels and bronchi (comet tail sign), adjacent pleural thickening, and volume loss on CT. All lesions were negative on FDG-PET. Four lesions were percutaneously biopsied and showed chronic inflammation consistent with RA. Two lesions were unchanged on 2 and 3 year follow-up CT and were presumed to be RA as were four other lesions with characteristic CT features and negative FDG-PET. CONCLUSION: Our experience suggest that RA in not metabolically active on FDG-PET imaging. Thus, FDG-PET scans can play a role in differentiating RA from malignancy when there are few or atypical features of RA on chest radiographs and CT.

Aged↗
PubMed1997

Evaluation of the reliability of computed tomographic criteria used in the diagnosis of round atelectasis.

The purpose of this controlled study was to determine the diagnostic accuracy of computed tomography (CT) in the diagnosis of round atelectasis (RA). We reviewed two groups of chest CT scans of 22 patients (with 24 masses). Group 1 scans represent 10 patients (12 masses) known to have RA, and Group 2 scans represent 12 patients with "RA look-alike" masses. Scans in both groups were selected for review by two of the authors and later independently reviewed by the other authors, who were blind to the actual diagnosis. Scans were rated for the presence/absence of 18 features ascribed to RA in the literature and assigned a percent probability of RA by each rater. Consensus was achieved for discordant ratings, and the individual percent probabilities were averaged to create a consensus probability. ROC curve analysis of the consensus percent probability showed that diagnostic accuracy significantly exceeded chance [area under curve (AUC) = 0.95, p < 0.001]. Of all the features of RA examined, the presence of converging bronchovascular markings discriminated best between RA and "RA look-alikes" (sensitivity 83%, specificity 92%, likelihood ratio 11). Presence of adjacent pleural thickening and pleural-based location were even more sensitive features of RA (100% each), but lacked specificity (33 and 67%, respectively; likelihood ratios 3 and 1.5, respectively). We conclude that (a) although the diagnostic accuracy of CT for RA was high in this series, radiographic diagnosis is imperfect and that (b) the presence of converging bronchovascular markings was the best discriminator between the two groups, but that no single CT feature permitted perfect discrimination.

Aged↗
PubMed1985

Large opaque hemithorax due to cardiomegaly and atelectasis.

We studied the clinical and radiologic features of five infants with a large opaque left hemithorax due to the combination of cardiomegaly and atelectasis. The causes of cardiomegaly were cardiomyopathy (two patients), congestive heart failure due to fluid overload, congenital mitral insufficiency, and idiopathic hypertrophic subaortic stenosis. In all five patients, there was initial total opacity of the left hemithorax with shift of the heart and mediastinum to the right due to the combination of cardiac enlargement and total lung collapse. The correct diagnosis may be suggested from conventional chest roentgenograms. Noninvasive supplementary studies, such as high-kilovolt roentgenography, fluoroscopy, esophagography, echocardiography, and radionuclide angiography, should be done for clarification.

Aortic Stenosis, Subvalvular↗
PubMed1986

Rounded atelectasis shown by computerized tomography.

We have reported a rounded atelectasis in a 65-year-old man. On CT scan a pleural-based mass was associated with curved, ragged projections from the lower pole of the lesion. This phenomenon appears to be the counterpart of the so-called comet tail on regular tomography and, because of its clarity, may further facilitate the diagnosis of this entity.

Aged↗
PubMed1986

Rounded atelectasis: a new criterion for benignancy.

A malignancy must be considered whenever a mass lesion is encountered on a chest roentgenogram. Unless an unequivocal diagnosis of a benign lesion is made, thoracotomy is usually indicated. Rounded atelectasis, while only having been recently described, is being encountered with increasing frequency. As illustrated by our three cases, radiologic diagnosis of this entity is a major criterion for judging the benignity of a mass and obviates the need for a thoracotomy.

Aged↗
PubMed2006

An anesthesiologist's guide to hypoxic pulmonary vasoconstriction: implications for managing single-lung anesthesia and atelectasis.

PURPOSE OF THE REVIEW: Hypoxic pulmonary vasoconstriction is the pulmonary circulation's homeostatic mechanism for matching regional perfusion to ventilation and optimizing systemic PaO2. The role of hypoxic pulmonary vasoconstriction in anesthesiology is reviewed. RECENT FINDINGS: In hypoxic pulmonary vasoconstriction, airway hypoxia causes resistance pulmonary arteries to constrict, diverting blood to better-oxygenated alveoli. Hypoxic pulmonary vasoconstriction optimizes O2 uptake in atelectasis, pneumonia, asthma, and adult respiratory distress syndrome. During single-lung anesthesia, hypoxic pulmonary vasoconstriction helps maintain systemic oxygenation. When hypoxic pulmonary vasoconstriction is weak, systemic hypoxemia is exacerbated. Although not widely used, the peripheral chemoreceptor agonist almitrine enhances hypoxic pulmonary vasoconstriction and improves PaO2 during single-lung anesthesia. The mechanism of hypoxic pulmonary vasoconstriction involves a redox-based O2 sensor within pulmonary artery smooth muscle cells. Pulmonary artery smooth muscle cells mitochondria vary production of reactive O2 species in proportion to PaO2. Hypoxic withdrawal of these redox second messengers inhibits voltage-gated potassium channels, depolarizing the pulmonary artery smooth muscle cells. Depolarization activates L-type calcium channels, increasing cytosolic calcium and triggering hypoxic pulmonary vasoconstriction. SUMMARY: An understanding of hypoxic pulmonary vasoconstriction is clinically relevant for anesthesiologists. Randomized clinical trials with robust endpoints are required to assess strategies for enhancing hypoxic pulmonary vasoconstriction in thoracic surgery patients.

Anesthesia, Inhalation↗
PubMed1986

Densities in dependent lung regions during anaesthesia: atelectasis or fluid accumulation?

In previous studied with computed tomography (CT) prior to and during general anaesthesia, we found that densities developed in dependent parts of the lungs immediately after induction of anaesthesia in all examined patients. It was suggested that the densities were atelectases created by compression of lung tissue but an alternative explanation could be accumulation of extravascular fluid in the lung tissue and/or in the pleural space. In the present study the nature of the densities was analysed in further detail. Injections of contrast medium into the pleural space revealed that the densities were located in the lung tissue and not in the pleural space. By injecting contrast medium intravenously and repeating the CT scanning over a 2-min period the passage of contrast through the major vessels and the lung densities could be studied. The transit time of the contrast medium was of the same magnitude in the densities and the major lung vessels. This indicates that there were no regions with an increased amount of extravascular fluid to delay the contrast passage. These findings oppose the idea of fluid accumulation as the cause of the densities, while atelectasis remains the most plausible explanation.

Adult↗
PubMed1990

Ventilation-perfusion relationships and atelectasis formation in the supine and lateral positions during conventional mechanical and differential ventilation.

Patients without respiratory symptoms were studied awake and during general anesthesia with mechanical ventilation prior to elective surgery. Ventilation-perfusion (VA/Q) relationships, gas exchange and atelectasis formation were studied during five different conditions: 1) supine, awake; 2) supine during anesthesia with conventional mechanical ventilation (CV); 3) in the left lateral position during CV; 4) as 3) but with 10 cm of positive end-expiratory pressure (PEEP) and 5) as 3) but using differential ventilation with selective PEEP (DV + SPEEP) to the dependent lung. Atelectatic areas and increases of shunt blood flow and blood flow to regions with low VA/Q ratios appeared after induction of anesthesia and CV. With the patients in the lateral position, further VA/Q mismatch with a fall in PaO2 and increased dead space ventilation was observed. Atelectatic lung areas were still present, although the total atelectatic area was slightly decreased. Some of the effects caused by the lateral position could be counteracted by adding PEEP. Perfusion of regions with low VA/Q ratios and venous admixture were then diminished, while PaO2 was slightly increased; shunt blood flow and dead space ventilation were essentially unchanged. During CV + PEEP, there was a decrease in cardiac output, compared to CV in the lateral position. DV + SPEEP was more effective than CV + PEEP in decreasing shunt flow and increasing PaO2 in the lateral position; in addition to this, cardiac output was not affected.

Adult↗
PubMed1992

CT appearances of rounded atelectasis.

Five patients examined with CT had lesions fulfilling criteria for a diagnosis of rounded atelectasis (RA) and these were managed without biopsy. In three patients unsuspected contralateral lesions were identified as RA variants, and one of these was biopsied at thoracotomy and proved to be benign. All patients remain well at 6-22 months follow-up. We concur with recent reports that there is a spectrum of CT appearances of RA and that even atypical lesions seldom need further investigation. We also suggest that the appearances of some atypical lesions add support for the fibrosing theory of pathogenesis of RA.

Aged↗
PubMed1990

[A case of pulmonary nocardiosis associated with middle lobe atelectasis].

Pulmonary nocardiosis is a rare disease. We reported a case of pulmonary nocardiosis associated with middle lobe atelectasis. A 66-year-old female was admitted to Saga Medical School Hospital with complaints of fever, productive cough and hemosputum. Nocardia asteroides was isolated from her sputum and bronchial lavage fluid. Administration of sulfamethoxazole-trimethoprim (ST) improved her symptoms and Nocardia asteroides were rapidly eliminated from her sputum. However, she had severe side effects of ST: toxic dermatitis, granulocytopenia and liver dysfunction, whereupon administration of ST was stopped. About two weeks later, Nocardia asteroides appeared again in her sputum. Either netilmicin (NTL) or minocycline (MINO) given consecutively could not eliminate Nocardia asteroides from her sputa. Subsequently a combination therapy of OFLX administration and gentamicin inhalation was tried. This treatment improved her symptoms and eradicated Nocardia asteroides from her sputa completely. In vitro study, ST, MINO and aminoglycosides showed good susceptibility against Nocardia asteroides. In this case, it was revealed that GM inhalation therapy is also very useful for pulmonary Nocardiosis.

Aged↗
PubMed1981

Rounded atelectasis and its association with asbestos-induced pleural disease.

Rounded atelectasis (RA) is an unusual form of peripheral lobar collapse which may present as a juxtapleural mass simulating a pulmonary neoplasm. Seven cases of RA were recently encountered in patients with asbestos-induced pleural disease. Since asbestos exposure is associated with mesothelioma, bronchogenic carcinoma, and other tumors, differentiation of RA from these neoplasms is essential in avoiding unnecessary thoracotomy. The radiographic features of RA are sufficiently characteristic, so that in the presence of chronic pleural thickening due to asbestos exposure, the diagnosis can be made with assurance and further work-up avoided.

Aged↗