Diagnosis Of Respiratory Distress Syndrome Research Articles

Pulmonary function, extravascular lung water and chest radiography in a porcine model of adult respiratory distress syndrome.

To study the pathophysiology and the value of chest radiography in the diagnosis of early adult respiratory distress syndrome spontaneously air-breathing pigs under ketamine anaesthesia were investigated. Five control animals received physiological saline and showed no notable changes in physiological or radiological data. Eleven animals were infused i.v. with E. coli endotoxin over 6 h. The pulmonary dysfunction in the endotoxin animals was characterized by an early increase in venous admixture with hypoxaemia and a peak increase in pulmonary vascular resistance at 0.5 h after start of endotoxin infusion. Subsequently there was a tendency towards a restitution to baseline physiology, but from 3 h onwards a "second wave" of pulmonary dysfunction developed in addition to an increase in extravascular lung water. No significant correlation (r = 0.44) existed between the increase in extravascular lung water and venous admixture. The increase in calculated pulmonary microvascular pressure correlated significantly (r = 0.77) with the increase in extravascular lung water. Radiographic signs of pulmonary oedema were sparse. Thus, only three of 11 animals displayed increased density on chest radiography indicative of pulmonary oedema.

The diagnosis, pathogenesis, and treatment of adult respiratory distress syndrome.

ARDS is well recognized as a major medical emergency resulting in respiratory failure and refractory hypoxemia. The risk factors and attack rate of ARDS have been identified and principles of management established. The pathogenesis involves the release of toxic cell products that damage the air-blood interface, resulting in pulmonary edema, loss of functioning lung units, and reduced compliance. Today, management is supportive and results in the salvage of approximately 40% of patients suffering ARDS from all causes. Certain roentgenographic features can be identified in both acute and late phases of ARDS. The prognosis of survivors is favorable in the long term.

Pulmonary occlusion (wedge) angiography in adult respiratory distress syndrome. A survey of angiographic appearances and outcomes.

Pulmonary occlusion angiography was performed in 34 patients admitted to the intensive therapy unit with a diagnosis of adult respiratory distress syndrome. Twenty angiograms were normal. Ten patients survived. No patient with abnormal angiography survived.

Adult respiratory distress syndrome in neutropenic patients

The precise pathophysiologic mechanisms that cause the adult respiratory distress syndrome are unknown. Indirect evidence from human studies and extrapolations from animal models have suggested that phagocytic neutrophils are important in the pathogenesis of this disease. To further evaluate the role of neutrophils, the frequency of neutropenia in 18 bacteremic patients who had the adult respiratory distress syndrome was compared with that in a control group who had bacteremia alone. Three of 18 patients in the group with the adult respiratory distress syndrome were neutropenic as opposed to one of 18 in the control group (p >0.6). Histologic examination of the lungs from two patients with the adult respiratory distress syndrome and neutropenia demonstrated the absence of neutrophils. It is likely that there are many pathways that lead to the adult respiratory distress syndrome. Although neutrophils may be involved in some of these processes, this study demonstrates that neutrophils are not required for the development of the syndrome. In the appropriate clinical setting, the diagnosis of the adult respiratory distress syndrome should not be excluded solely because of neutropenia.

Survival in Adult Respiratory Distress Syndrome Caused by Blastomycosis Infection

A 32-year-old man with diabetes had rapid development of acute respiratory failure and severe hypoxemia. Radiologic and hemodynamic evaluation confirmed the clinical diagnosis of adult respiratory distress syndrome, and open-lung biopsy disclosed blastomycosis as the etiologic agent. The survival of this patient, after amphotericin therapy, to our knowledge is the first reported recovery from substantiated adult respiratory distress syndrome secondary to blastomycosis.

T-lymphocyte analysis in the early diagnosis of adult respiratory distress syndrome

Adult respiratory distress syndrome occurs concomitantly with a number of clinical conditions but has no known cause. At present, there is no generally acceptable method for establishing the early diagnosis. In the course of studying immune aberrations by means of monoclonal antibody staining and fluorescence-activated cell sorting in injured patients, we noted an apparent specific T-lymphocyte response to this syndrome in one patient. There was an increase in suppressor T-cells and a decrease in helper/suppressor T-lymphocyte ratio (normal = 1.57). When the patient recovered, the helper/suppressor ratio rose to above 3.0. T-lymphocyte analysis offers a promising means of evaluating patients considered highly susceptible to adult respiratory distress syndrome, i.e., victims of massive trauma. Further studies will be required to fully elucidate this possibility.

THE TRACHEAL ASPIRATE LUNG PROFILE

The lecithin/sphingomyelin (L/S) ratio & percent phosphatidyl glycerol (PG) in amniotic fluid are used to evaluate fetal lung maturity, but their value in tracheal aspirates to predict respiratory distress syndrome (RDS) has not been defined. Phospholipid lung profiles on tracheal aspirates within 12 hrs of birth from 551 babies were analyzed by 2-dimensional thin layer chromatography & reflectance densitometry. Infants with respiration, asphyxia, pneumonia, syndromes, chorioamionitis, IUGR, or pulmonary hypoplasia were excluded. Radiologic & clinical criteria were used to classify the remaining patients as RDS (125), retained lung fluid (RLF) (50), or no respiratory disease (60). L/S best predicted RDS (78%) when values were ≤2.6 & identified normals (85%) above 2.6. The mean L/S for RLF (4.06) & normals (4.37) were higher than for RDS (2.3). Accuracy of PG in predicting RDS was best (96%) at trace (<1%) or less, identifying 83% of normals. Seventeen percent of normals & 56% of RLF had <1% PG, while 4% of RDS cases had ≥1% PG. Lung profile values accepted for amniotic fluid seem to overestimate pulmonary maturity when applied to tracheal aspirates. Tracheal aspirate L/S & PG together are highly useful in the biochemical diagnosis of RDS.

The Value of Variables of Disseminated Intravascular Coagulation in the Diagnosis of Adult Respiratory Distress Syndrome

In an investigation on 19 patients with traumatic (n = 11) and septic (n = 8) shock, at risk of developing adult respiratory distress syndrome (ARDS), various coagulation and fibrinolysis variables and also blood gases and chest x-ray were monitored. Eight patients developed ARDS - two after traumatic shock and six following septic shock. the conventional disseminated intravascular coagulation variables (fibrinogen, platelet counts, activated partial thromboplastin time, ethanol gelation test, thrombotest, normotest and fibrin degradation products) could not discriminate between ARDS and non-ARDS patients, but showed an essentially similar reaction pattern in these two groups. Antithrombin-III and plasminogen levels were significantly lower in patients with ARDS, while factor VIII-related antigen levels were significantly higher in ARDS than in non-ARDS patients. patients with septic shock run a significantly greater risk of developing ARDS (6 of 8) than those with traumatic shock (2 of 11; P less than 0.02). Furthermore, the onset of ARDS after septic shock seems to occur in a more rapid way, while ARDS following traumatic shock develops more gradually. Early ventilator treatment with positive end expiratory pressure counteracts the classical radiographic picture of ARDS with bilateral alveolar densities.

Radionuclide evaluation of lung trauma

Nuclear medicine imaging procedures can play a significant role in evaluating the pulmonary complications that are seen in trauma patients. A quantitative method for measuring increased pulmonary capillary permeability that uses Tc-99m HSA allows early diagnosis of acute respiratory distress syndrome (ARDS) and accurately differentiates this condition from pneumonia or cardiogenic pulmonary edema. This technique may be of great value in following the response to therapy. The use of 133Xe to diagnose inhalation injury remains an important diagnostic tool, particularly at hospitals with specialized burn units. Regional decreases in ventilation-perfusion images reliably localize aspirated foreign bodies. Radionuclide techniques that are used to demonstrate gastropulmonary aspiration remain controversial and require further clinical evaluation. Pulmonary perfusion imaging, although nonspecific, may provide the earliest clue for correct diagnosis of fat embolism, air embolism, contusion, or laceration. Furthermore, the possibility of perfusion abnormality due to these uncommon conditions must be remembered whenever trauma patients are evaluated for pulmonary thromboembolism with scintigraphy. Occasionally, liver or spleen scintigraphy may be the most appropriate procedure when penetrating chest trauma also involves these subdiaphragmatic organs.

Procoagulant Activity of Tracheal and Hypopharyngeal Aspirates and the Diagnosis of Respiratory Distress Syndrome in Newborns

Procoagulant Activity of Tracheal and Hypopharyngeal Aspirates and the Diagnosis of Respiratory Distress Syndrome in Newborns

Diagnosis of adult respiratory distress syndrome associated with underlying severe emphysema

Diagnosis of adult respiratory distress syndrome associated with underlying severe emphysema

Diagnosis of Adult Respiratory Distress Syndrome Associated With Underlying Severe Emphysema

Adult respiratory distress syndrome (ARDS) notably produces bilateral homogeneous alveolar infiltrates and decreased lung compliance. We encountered a patient whose severe underlying emphysema altered these distinctive clinical features. The chest roentgenogram showed bilateral infiltrates containing multiple radiolucencies that simulated a cavitary process. Also, lung-chest wall compliances measured during mechanical ventilation were higher than usually observed in patients with ARDS. We suggest that the pathologic features of the emphysematous lung with multiple blebs and decreased elastic recoil properties impart these unique findings. When ARDS develops in a patient with severe underlying emphysema, an atypical presentation may produce a confusing clinical picture.

Adult Respiratory Distress Syndrome in the Course of Acute Myocardial Infarction

The diagnosis of adult respiratory distress syndrome (ARDS) has been made in our intensive coronary care unit in four patients during the course of acute myocardial infarction (AMI). In all four patients, the syndrome manifested itself either after resuscitation or after a transient hypotensive state. In two of the patients none of the conditions known to be possible etiologies of ARDS was present; in the third, smoke inhalation preceded; and in the fourth, aspiration followed the AMI. The clinical and x-ray pictures were indistinguishable from acute left heart failure, the PaO2 levels were about 40 mm Hg, and a low pulmonary arterial wedge pressure was measured in all cases. Positive end-expiratory pressure was used successfully, combined with other therapeutic measures, and three patients recovered from the ARDS. The association of ARDS and AMI carries a grave risk in view of the additional damage that may be caused by the severe hypoxemia to the already compromised myocardium. The AMI, if complicated by circulatory arrest, cardiogenic shock, or hypotension, seems to be an etiologic factor in the development of ARDS and it should be added to the growing list of conditions that may give rise to this new syndrome.

The hazards of anesthesia and surgery in bleomycin-treated patients.

T HE USE OF bleomycin therapy in the treatment of certain cancers before definitive surgery is gaining increasing acceptance. It is our belief at Memorial Sloan-Kettering Cancer Center that antecedent bleomycin therapy predisposes the patient to the postoperative development of the acute adult respiratory distress syndrome. Included in this report is data that confirms that the problem exists and identifies the tentative cause and solution. Initially the problem of acute postoperative respiratory failure occurred in patients receiving antecedent bleomycin therapy for dysgenetic neoplasm of the male gonads and metastatic teratocarcinoma of the testicle. The increasing use of bleomycin over the following several years had made the recognition of the problem more important, as evidenced by a report by Nygaard et al.’ in January 1978 of pulmonary complications in a group of patients with esophageal cancer treated by bleomycin before the definitive surgery. A potent and effective chemotherapeutic agent bleomycin is well known to produce acute interstitial pneumonia or chronic fibrotic changes in the lung. Five patients who received bleomycin 612 mo prior to surgery developed severe respiratory distress 3-5 days following surgery. Despite aggressive respiratory care including respirator support, positive end-expiratory pressure and, in one case, the use of a membrane oxygenator for 8 days, all 5 patients died from a rapidly progressing interstitial pneumonia. Autopsy in each case revealed increased size and weight of the lungs with abnormal amounts of interstitial fluid. On microscopic and ultramicroscopic examination of the lungs, there was interstitial fibrosis, destruction of Type I and Type II pneumocytes, alveolar wall and capillary damage, all consistent with the general diagnosis of adult respiratory distress syndrome. Cultures for bacterial and viral pathogens were negative in vivo and at autopsy. It was felt that two factors might be related to the high postoperative mortality in these bleomycin-treated patients. One was the concentration of inspired oxygen during the long surgical

Gastrointestinal Hemorrhage in Patients in a Respiratory Intensive Care Unit

Significant gastrointestinal hemorrhage occurred in 20% (20) of the patients in a respiratory intensive care unit. Risk factors significantly associated with the development of gastrointestinal hemorrhage included (1) the principal respiratory diagnosis of adult respiratory distress syndrome; (2) increasing numbers of days on a ventilator, days in the respiratory intensive care unit, and total days of hospitalization; and (3) the development of thrombocytopenia. Factors not associated with an increased risk of gastrointestinal hemorrhage were the age and sex of the patient, the respiratory diagnosis of chronic obstructive pulmonary disease, and the use of therapy with either heparin or corticosteroids. Routine prophylactic administration of antacids was associated with a decreased incidence of hemorrhage. The mortality of bleeders was significantly greater than that of nonbleeders.

Foam-Stability Test on Gastric Aspirate and the Diagnosis of Respiratory-Distress Syndrome

Gastric aspirate, collected from 79 infants within 30 minutes of birth, was subjected to the foam-stability test. The lecithin/sphingomyelin ratio was determined in 27. The results were compared with the incidence of respiratory-distress syndrome as determined independently by different investigators. Of the 59 infants with a positive foam-stability test on gastric aspirate, three had transient respiratory distress, and one the respiratory-distress syndrome; 17 of 22 had lecithin/sphingomyelin ratios greater than 2.0. Of nine infants who had intermediate test results, three were normal, four had transient respiratory distress, and two had the respiratory-distress syndrome. In all the 11 infants with negative foam-stability tests the respiratory-distress syndrome developed. The three gastric aspirates tested in this group had lecithin/sphingomyelin ratios of less than 1.5. These data indicate that the foam-stability test on gastric aspirate is a reliable index of fetal lung maturity in infants whose amniotic fluid is not available.

Pressure volume curves of lamb lungs and the lecithin-sphingomyelin ratios of lung fluid.

Pressure-volume curves were made of lungs from non-distressed, from asphyxiated and from distressed lambs. The curves of the non-distressed animals differed from the curves of the asphyxiated and of the distressed group. Eleven stability indices were calculated and the summation of these in situ surfactant characteristics was used for individual respiratory distress syndrome diagnosis. Low values (less than 2) of lecithin/sphingomyelin (L/S) ratios in lung fluid were found before the 130th day of gestation, but a steep increase of the L/S ratio was present after that period. Postnatal RDS was found in low L/S ratio cases, whereas normal lung stability was noticed in animals with L/S ratios greater than 2. It is concluded that the prenatal L/S ratio in lung fluid of lambs is of predicting value in RDS experiments and fits well with lung stability characteristics.

Prenatal diagnosis of respiratory distress syndrome and its basis.

Prenatal diagnosis of respiratory distress syndrome and its basis.

Total anomalous pulmonary venous return (TAPVR) with obstruction at the atrial septum (palliation with balloon septostomy and open atrial septectomy)

Total anomalous pulmonary venous return (TAPVR) with obstruction at the atrial septum (palliation with balloon septostomy and open atrial septectomy)

Biochemical development of surface activity in mammalian lung. IV. Pulmonary lecithin synthesis in the human fetus and newborn and etiology of the respiratory distress syndrome.

Extract: The surface-active complex lining alveoli in normal lung lowers surface tension on expiration, thus preventing alveolar collapse. Surface activity follows a developmental timetable. Infants with idiopathic respiratory distress syndrome (RDS) almost exclusively are prematurely born, and their lungs lack adequate surface activity and are deficient in the principal surface-active component, lecithin. This deficiency implies that RDS is a “disease of development,” with fetal and neonatal timetables for lecithin synthesis. The biosynthesis of lung lecithin in the living human infant was studied by examining phospholipids in lung effluent (pharyngeal aspirates, mucus), which have identical phospholipids to those in lung lavage (alveolar wash). The fatty acid esters of isolated lecithin and phosphatidyl dimethylethanolamine (PDME) were examined. The β-carbon fatty acids are indicators of the primary pathways of synthesis of lecithin: (1) a preponderance of palmitic acid signifying cytidine diphosphate choline (CDP-choline) + D-α,β-diglyceride → lecithin (choline incorporation pathway) and (2) a preponderance of myristic acid signifying phosphatidyl ethanolamine (PE) + 2 CH3 → PDME + CH3 → lecithin (methylation pathway). Fetal lung of 18 and 20 weeks showed slight incorporation by CDP-choline pathway, absence of PDME, and almost no methylation. Salivary lecithin had totally different fatty acids from lecithin in aspirates. Phosphatidyl dimethylethanolamine (PDME) (therefore methylation) was identified in aspirates as early as 22–24 week-gestation. Lecithin fatty acid esters in aspirates from premature infants after birth or those with no RDS closely resembled PDME fatty acids. With RDS, PDME disappears and β-carbon palmitic acid (therefore dipalmitoyl lecithin) increases. With recovery, PDME reappears, as does the premature infant's major lecithin, palmitoylmyristoyl. Full term infants are born with more β-carbon palmitic acid (20–40%) and by 12–18 hr have equal palmitic and myristic acids, indicating function of both lecithin synthesis pathways. Stress (hypoxia acidosis, hypothermia) cause disappearance of PDME and loss of β-carbon myristic acid. Similar changes in full term infants who do not get RDS are due to adequate lecithin synthesis by the GDP-choline pathway. The capacity to synthesize lecithin in the lung by methylation in the human fetus and newborn allows the human to be born prematurely; rabbits and sheep lack this capacity and cannot be prematures, but die from respiratory insufficiency if born too soon. Speculation: The diagnosis of RDS can be made objectively by looking for PDME in aspirates (lung effluent). Prognosis also can be established by lack or presence of PDME. The effects of various therapies also can be assessed this way. The techniques and consideration described herein can be employed to study biochemically the effects of other stresses to lung, including oxygen toxicity and anesthesia.