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Biomedical subjects

C M Roos

Publications and source records attributed to C M Roos.

At least 37 records · Page 2Linked to original sources
PubMed1993

Standardized quantitative 67Ga scintigraphy in relation to carbon monoxide diffusion capacity in pulmonary sarcoidosis.

67Ga lung uptake, obtained by a standardized computer-assisted quantitative method of 67Ga scintigraphy, was compared to carbon monoxide diffusion capacity (DLCO) in 45 patients with biopsy proven pulmonary sarcoidosis. Increased 67Ga lung uptake was found in 24 (53%) patients and DLCO was decreased in only 16 (36%) patients. An inverse relationship (r = -0.53; p < 0.001) was demonstrated between 67Ga lung uptake and DLCO. Eleven patients had an increased 67Ga lung uptake whereas the DLCO values were normal. There was no correlation between 67Ga lung uptake or DLCO and either chest radiographic stage or mode of clinical presentation. On the basis of the normal limits for 67Ga lung uptake and DLCO, 4 subgroups of patients could be identified. The use of the combined investigations may open an opportunity for an early identification of those patients who require therapy. An increased 67Ga accumulation within the lung seems to be considered as a factor indicating risk for pulmonary disability, which is supported by the follow-up of the 4 subgroups of patients.

Adult↗
PubMed1993

Inhaled nitric oxide. Selective pulmonary vasodilation in cardiac surgical patients.

BACKGROUND: Inhaled nitric oxide (NO), an endothelium-derived relaxing factor, is a selective pulmonary vasodilator. The authors investigated whether the pulmonary vasodilation resulting from 20 ppm inhaled NO is related to the degree of pulmonary hypertension or affected by cardiopulmonary bypass (CPB) or the presence of intravenous nitrates. METHODS: In patients undergoing cardiac surgery (n = 20) or in whom the circulation was supported with a ventricular assist device (VAD; n = 5), the lungs were ventilated with 80% O2 and 20% N2 followed by the same gas concentrations containing 20 ppm NO for 6 min. RESULTS: Inhaled NO decreased (P < 0.05) the pulmonary artery pressure from 36 +/- 3 to 29 +/- 2 mmHg and 32 +/- 2 to 27 +/- 1 mmHg, before and after CPB, respectively, and from 68 +/- 12 to 55 +/- 9 mmHg in patients with a VAD. Similarly, the pulmonary vascular resistance (PVR) decreased (P < 0.05) from 387 +/- 44 to 253 +/- 26 dyne.cm.s-5 and 260 +/- 27 to 182 +/- 18 dyne.cm.s-5, before and after CPB, respectively, and from 1,085 +/- 229 to 752 +/- 130 dyne.cm.s-5 in patients with a VAD. Central venous pressure, cardiac output, systemic hemodynamics, and blood gases did not change after inhalation of NO before or after CPB, whereas arterial oxygen tension, mixed venous hemoglobin saturation, and mean arterial pressure increased (P < 0.05) in patients supported with a VAD. All hemodynamic and laboratory data returned to control 6 min after discontinuation of NO. The decrease in PVR was proportional to baseline PVR (delta PVR = -0.45 PVRb + 39.9) before CPB. The pre- and post-CPB slopes were identical despite possible damage to the endothelium resulting from CPB and the post-CPB presence of intravenous nitroglycerin (17 of 20 patients). CONCLUSIONS: This study demonstrates that 20 ppm inhaled NO is a selective pulmonary vasodilator in cardiac surgical patients before and after CPB and in patients in whom the circulation is supported with a VAD. Furthermore, NO-induced pulmonary vasodilation is proportional to PVRb and does not appear to be altered by CPB, the presence of a VAD, or infusion of nitrates.

Administration, Inhalation↗
PubMed1992

Pressure and X-ray recording of reflux into the thoracic stomach.

Anastomotic leakage, pulmonary aspiration and reflux-esophagitis might be induced or aggravated by the increased duodenogastric reflux observed in the thoracic stomach. In this study, the effect of respiration on the reflux-promoting pressure gradient in the intrathoracally located stomach was assessed. In nine patients pressure recording was done in the duodenum and the abdominal and thoracic part of the stomach. Intrapleural pressure was determined by recording mouth pressure during inspiratory occlusion. In addition, the course of injected contrast was examined fluoroscopically. The mean end-expiratory pressure gradient in the thoracic part of the stomach was 0.8 cm H2O, increasing up to 6.0 cm H2O and 21.3 cm H2O during normal and forced inspiration, respectively. Fluoroscopic examination showed reflux of contrast that coincided with the downward movement of the diaphragm. From this study, we conclude that reflux into the thoracic stomach is promoted by intraluminal pressure fluctuations induced by voluntary breathing. Performing a pyloroplasty or -myotomy after intrathoracic esophagogastrostomy destroys the integrity of the pyloric sphincter as a barrier to reflux, thus promoting duodenogastric reflux.

Duodenogastric Reflux↗
PubMed1991

Respiratory membrane permeability and bronchial hyperreactivity in patients with stable asthma. Effects of therapy with inhaled steroids.

In patients with stable asthma, we assayed plasma proteins in the bronchoalveolar lavage fluid to obtain information on plasma exudation into the airways. Fourteen nonsmoking patients with asthma who were in a stable period of their disease and eight nonsmoking healthy volunteers were studied. The ratios of the concentrations of albumin, ceruloplasmin (CP), and alpha-2-macroglobulin (A2M) between blood and epithelial lining fluid were calculated (cQalb, cQCP, and cQA2M). The cQalb was increased in the patients (Mann-Whitney U test, p less than 0.05). In 10 patients the bronchial hyperreactivity was assessed with histamine provocation tests. Significant relationships between the cQalb, cQCP, and cQA2M on the one hand and PC15 on the other hand were found (Spearman's rank correlation: r = -0.62, p less than 0.05; r = -0.61, p less than 0.05; r = -0.79, p less than 0.01, respectively). Fourteen patients were treated with two inhalations of 200 micrograms glucocorticosteroids per day in a 3-month prospective study. Three of them were excluded from further study because of an intercurrent exacerbation of asthmatic symptoms during therapy. In the 11 patients with stable asthma, the cQalb and cQA2M decreased after treatment with inhaled steroids (Wilcoxon's matched pairs signed rank test, p less than 0.03). Our results show that in patients with stable asthma, there is an increased plasma exudation into the airways, most likely caused by an increased respiratory membrane permeability. The plasma exudation correlated with the bronchial hyperreactivity to histamine, and it decreased after corticosteroid therapy.

Administration, Inhalation↗
PubMed1990

Lung function 8-18 years after intermittent positive pressure ventilation for hyaline membrane disease.

Lung function and respiratory symptoms were studied in 40 children aged 8-18 years who had been ventilated for hyaline membrane disease after birth; 11 had had bronchopulmonary dysplasia. Also studied were 38 age matched children who had had hyaline membrane disease but had not required ventilation, 25 unmatched children who were born prematurely but did not develop hyaline membrane disease, and 39 randomly selected pupils of similar age. There was no difference in thoracic gas volume, total lung capacity, inspiratory vital capacity, residual volume, or transfer factor for carbon monoxide between the groups. Respiratory symptoms during the three years before the study and the frequency of clinically diagnosed asthma in patients and their family were similar in all the children with hyaline membrane disease irrespective of whether they had been ventilated or had had bronchopulmonary dysplasia. The children with bronchopulmonary dysplasia, however, had a lower forced expiratory volume in one second (FEV1) before bronchodilator (73% predicted) than the other groups (88-95% predicted). Children who had required ventilation had lower values for specific airways conductance (sGaw) and a greater increase in FEV1 (delta FEV1) after salbutamol (13%) than non-ventilated children (6%); delta FEV1 was associated with the peak pressure of intermittent positive pressure ventilation, a family history of asthma and a history of wheezing, recurrent respiratory illnesses, and a doctor's diagnosis of asthma during the three years before the study. These findings indicate that after eight years of age patients with bronchopulmonary dysplasia have more reversible airways obstruction, compatible with increased bronchial smooth muscle tone.

Adolescent↗
PubMed1988

Lung volume calculations from 81Krm SPECT for the quantification of regional ventilation.

Lung volumes, calculated from 81Krm single-photon emission computed tomography (SPECT) of the lungs, were compared with functional residual capacity (FRC), measured with the helium dilution technique in controls and in patients with various pulmonary diseases. SPECT volume was greater than FRC, which was attributed to non-gas-containing structures in the lung such as the alveolar walls, the interstitium, the blood vessels and the blood, included in the SPECT volume. A good correlation (r = 0.91) was found between the two volumes and there was no difference in this relationship between patients and controls. It was concluded that the relative volume distribution, calculated from SPECT, can be used for the quantification of ventilation from 81Krm SPECT steady-state count distributions.

Adult↗
PubMed1987

Whole-lung lavage under hyperbaric oxygen conditions for alveolar proteinosis with respiratory failure.

Whole-lung lavage under hyperbaric oxygen conditions was performed in two patients suffering from severe respiratory insufficiency in pulmonary alveolar proteinosis. Under these conditions, gas exchange was maintained and the mixed venous partial pressure of oxygen and oxygen saturation showed increases to acceptable levels. This enabled us to limit the FIO2 in order to extend the oxygen tolerance and to perform lavage procedures more effectively. Both patients showed a very significant improvement of their clinical course, and we conclude that elective use of hyperbaric oxygen in unilateral lung lavages should be considered in these severe cases.

Adult↗
PubMed1987

Distribution of ventilation-perfusion ratios in pulmonary sarcoidosis.

In 14 patients with advanced stage pulmonary sarcoidosis the distribution of regional ventilation-perfusion ratios (V/Q) was obtained by quantitative analysis of ventilation-perfusion single photon emission computed tomography (SPECT) of the lungs. In 6 patients normal V/Q distributions were found with a decreased DLCO in only one of them. In 8 patients abnormal distributions of V/Q ratios were found. Six of these patients also had a decrease in diffusing capacity for CO (DLCO). It is suggested that the decrease in DLCO in these patients is partly a result of uneven distribution of V/Q ratios.

Adult↗
PubMed1986

Pharmacokinetic-pharmacodynamic modeling of terbutaline bronchodilation in asthma.

The study of terbutaline pharmacodynamics in patients with asthma is hampered by interfering stimuli when steady-state methods are employed. With pharmacokinetic-dynamic modeling, many of these interferences can be avoided. Using this technique, we studied the effect of terbutaline on lung function in 10 asthmatic patients with greater than 15% lung function reversibility. Terbutaline plasma concentrations, forced expiratory volume in 1 second (FEV1) airway resistance (Raw), and specific airway conductance (sGaw) were measured before and during 7 hours after subcutaneous dosing with 0.75 mg terbutaline. A hyperbolic concentration-effect relation was found. Fitting the time course of the effects required an effect compartment in the integrated model. Thus the delay between plasma concentration and effect time course was characterized by the rate constant ke0. Essentially the same ke0 was found for FEv1, Raw, and sGaw, indicating that the concerning receptors are "localized" in the same pharmacokinetic compartment. Of the lung function measures, sGaw was less sensitive to terbutaline than Raw and FEV1, whereas the latter tended to be the most sensitive one.

Adolescent↗
PubMed1983

67Ga scintigraphy, serum lysozyme and angiotensin-converting enzyme in pulmonary sarcoidosis.

67Ga scintigraphy, using a 67Ga accumulation score, was compared with serum lysozyme (LZM) and angiotensin-converting enzyme (ACE) levels in 34 patients with biopsy-proven, pulmonary sarcoidosis. Serum LZM and ACE values varied between 1.0 to 21.3 mg/l (mean 4.3 +/- 3.4 mg/l) and 33 to 146 U/l (mean 69 +/- 26 U/l), respectively. Normal values were found in 26 and 35% of the patients. All patients, however, had abnormal 67Ga uptake in the pulmonary hilar lymph nodes and/or parenchyma. The follow-up of untreated and treated patients supports the suggestion that 67Ga scintigraphy is more useful for assessing the extent and activity of the intrathoracic sarcoid lesions. Serum LZM and ACE measurements are helpful, but normal LZM and ACE values do not exclude activity and progression of disease in pulmonary sarcoidosis.

Adult↗