Biomedical subjects

F S Vargas

Publications and source records attributed to F S Vargas.

At least 55 records · Page 3Linked to original sources

PubMed1994

Arrhythmogenic effects of combined orally administered theophylline and albuterol in patients with chronic obstructive pulmonary disease.

1. Studies in asthmatic subjects have reported conflicting results about the arrhythmogenic effects of beta agonist and theophylline. The purpose of the present study was to evaluate the effects of the combination of these drugs in patients with chronic obstructive pulmonary disease (COPD). 2. Twelve COPD patients (FEV1 = 1.2 +/- 0.3 L; PaO2 = 65.7 +/- 9.0 mmHg) were evaluated by 24-h Holter monitoring on three different days. The first evaluation was done after the patient had been without any treatment for at least 24 h, the second after sustained-release theophylline for one week and the third after oral beta agonist (albuterol) and theophylline for one week. 3. Mean serum level of theophylline was 1.9, 15.6 and 11.7 micrograms/ml, and mean heart rate was 78.3, 82.0 and 84.5 beats/min for the first, second and third period, respectively. Four patients showed more than 10 premature atrial contractions/h in the baseline Holter, and this rate did not increase after either treatment. Three patients had more than 10 premature ventricular contractions/h (PVC) at baseline, with no increase while receiving theophylline or the combination of theophylline and albuterol. However, one patient did have worsening of the arrhythmia while taking both drugs. There were 5 single PVCs/h at baseline and 150 single and 9 coupled PVCs/h plus 1 episode of non-sustained ventricular tachycardia during combined therapy. 4. We conclude that the combination of theophylline and a beta agonist (albuterol) may increase the premature ventricular contraction rate and the complexity of ectopic activity in COPD patients.

Administration, Oral↗

PubMed1993

Influence of atelectasis on pulmonary function after coronary artery bypass grafting.

The purpose of this study was to determine the influence of atelectasis on pulmonary function 6 days following coronary artery bypass grafting (CABG). After 6 days, 30 patients had normal chest radiographs, 38 had atelectasis, and 57 had pleural changes. In 11 patients, atelectasis only was observed in the radiograph, and in 27 it was in combination with pleural changes. The decrease in FVC and FEV1 in the patients with atelectasis was 33.4 and 33.5 percent in the SVG group and 34.8 and 34.3 percent in the IMA group, while in those patients with a normal radiograph, the decrements were 26.3 and 26.9 percent in SVG group and 26.1 and 26.9 percent in IMA group, respectively. Thus, patients with atelectasis on the 6th postoperative day have a larger decrement in pulmonary function post CABG than the patients with normal chest radiograph and this reduction reflects a higher degree of thoracic trauma.

Coronary Artery Bypass↗

PubMed1993

Effectiveness of bleomycin in comparison to tetracycline as pleural sclerosing agent in rabbits.

The two agents most commonly used for producing a pleurodesis are tetracycline and bleomycin. Tetracycline is no longer available due to more stringent requirements on the manufacturing process. The objective of this project was to determine whether bleomycin is an effective sclerosant in an experimental model in rabbits. The following medications were instilled intrapleurally in anesthetized male rabbits: tetracycline, 35 mg/kg, or bleomycin, 1.5 or 3.0 IU/kg diluted to a total volume of 1 ml with bacteriostatic saline solution. Twenty-eight days after the instillation, the animals were killed, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The intrapleural injection of bleomycin was ineffective in creating pleural fibrosis, either grossly or microscopically. The mean degree of gross pleurodesis in the six rabbits who received tetracycline was 2.7 +/- 1.5 (scale 0 to 4), while that in the rabbits who received the highest dose of bleomycin was 0.0 +/- 0.0. Based on this study, we recommend that bleomycin not be used as a pleural sclerosant in patients with nonneoplastic pleural disease, eg, those with pneumothorax, congestive heart failure or cirrhosis, and pleural effusion.

Analysis of Variance↗

PubMed1992

Theophylline metabolism in patients with hepatosplenic mansoniasis and cirrhosis.

The pharmacokinetics of theophylline were studied in 12 patients with hepatosplenic mansoniasis, 14 patients with cirrhosis and 16 normal controls. Following a single intravenous dose of aminophylline volumes of distribution, serum half-lives and body clearances were determined. Volumes of distribution of theophylline in patients with schistosomiasis (mean 0.624 l/kg) did not differ from cirrhotic patients (mean 0.616 l/kg) or normal controls (mean 0.593 l/kg). Cirrhotic patients had a prolonged half-life compared to normal subjects (mean 22.1 vs. 9.9 h), while patients with schistosomiasis did not substantially differ from normal controls (15.8 vs. 9.9 h). Body clearance in patients with schistosomiasis was similar to controls (34.02 vs. 49.20 ml/h per kg) but decreased (29.24 ml/h per kg) in patients with cirrhosis. Individual analysis of the group with schistosomiasis disclosed three patients with reduced theophylline elimination. No relationship was found between laboratory tests of liver function and the pharmacokinetics of theophylline in any group. The administration of theophylline to patients with hepatosplenic schistosomiasis, although less dangerous than in cirrhosis, must be closely followed.

Adolescent↗

PubMed1992

Postoperative pleural changes after coronary revascularization. Comparison between saphenous vein and internal mammary artery grafting.

Coronary artery bypass grafting (CABG) is commonly performed with a saphenous vein graft (SVG) and/or an internal mammary artery graft (IMA). We hypothesized that there would be a higher incidence of pleural changes after CABG in patients who underwent IMA grafting because pleurotomy is usually performed. In the present study, the pre and the 6th postoperative day chest roentgenograms of 122 patients who received CABG were reviewed. The incidence of effusion in the patients who received only SVG was 43 percent (23/54) and did not differ significantly (p greater than 0.05) from the incidence in the patients who also had IMA 41 percent (28/68). Almost all of the patients (43/51) had unilateral left-sided pleural effusions. Most of the effusions were small and did not require treatment. The incidence of effusion was not higher in patients with enlargement of their cardiac silhouette or atelectasis and was not related to the presence of chest tubes. The incidence of pleural thickening was higher in the IMA group (49 percent) than in the SVG group (31 percent) but the difference did not achieve statistical significance (p greater than 0.05). We conclude that there is a high (approximately 40 percent) incidence of small effusions and thickening after CABG. The incidence of pleural effusion and pleural thickening do not appear to be influenced by the type of surgery (IMA vs SVG). We speculate that the effusions are due to pericardial inflammation.

Coronary Artery Bypass↗

PubMed1992

Effect of inhaled furosemide on the bronchial response to lysine-aspirin inhalation in asthmatic subjects.

It has been demonstrated recently that inhaled furosemide inhibits bronchoconstriction induced by cold air, physical exercise, various antigens, and metabisulfite. The goal of the present study was to determine if the inhalation of furosemide would inhibit the bronchoconstriction resulting from the inhalation of lysine-aspirin in aspirin-sensitive asthmatics. Six female subjects with known hypersensitivity to aspirin participated in this crossover study comparing 20 mg of inhaled furosemide and placebo. The volunteers inhaled increasing concentrations of lysine-aspirin after the inhalation of furosemide or placebo. The geometric mean provocative dose causing a 20 percent decrease in the FEV1 (PD20) after the inhalation of placebo was 30.4 mg/ml and the PD20 was equal or below 90 mg/ml in all patients. In contrast, the FEV1 did not decrease by 20 percent in any of the patients pretreated with furosemide when the inhaled concentration was increased to 360 mg/ml. From this study, we conclude that the administration of furosemide blocks the bronchospasm induced by the inhalation of lysine-aspirin in aspirin-sensitive asthmatics.

Administration, Inhalation↗

PubMed1992

Relationship between pleural changes after myocardial revascularization and pulmonary mechanics.

It is known that coronary artery bypass grafting (CABG) results in impairment of postoperative pulmonary function. There is also a high incidence of pleural changes (pleural effusion or pleural thickening) after CABG. We hypothesized that those patients with pleural changes in the postoperative period would have a greater decrease in pulmonary function test (PFTs) results. The present study reports the results of 110 male patients who underwent CABG. The chest films and the PFT results obtained preoperatively and on the sixth postoperative day were reviewed. The relationship between pleural changes and PFTs was analyzed in patients who received saphenous vein graft alone (SVG group: 50 patients) or in combination with internal mammary artery grafting (IMA group: 60 patients). In the IMA group, the patients who had pleural changes had significantly greater decreases in their pulmonary function than did the patients without pleural changes. The decrease in the FVC, TLC and FEV1 in the patients with pleural effusions (37.6, 27.8 and 36.8 percent) was similar to that in patients with pleural thickening (34.6, 28.3 and 35.0 percent) and both were significantly greater (p < 0.05) than the changes in the patients with a normal radiograph (26.1, 17.6 and 26.9 percent). In the SVG group, the presence of pleural changes was not significantly related to the decrement in pulmonary function. The values of RV, FRC, Cst, and blood gases were not affected in the SVG or IMA group by the presence of pleural changes. We conclude that the presence of pleural changes on the chest radiograph is associated with a larger decrement of pulmonary function after CABG in the IMA group. This larger decrease probably reflects added thoracic trauma and is not due to the presence of pleural changes per se.

Coronary Artery Bypass↗

PubMed1992

Arterial blood gases after coronary artery bypass surgery.

Coronary artery bypass graft (CABG) surgery adversely affects arterial blood gas (ABG) determinations. The purposes of this study were to assess serial changes in ABGs following bypass surgery and identify factors that may influence these changes. Room air ABGs were obtained preoperatively and on days 1, 2, 4, 6, and 8 postoperatively on 125 patients undergoing bypass surgery. Fifty-five patients (saphenous vein grafting [SVG] group) had only SVG grafting while 70 (internal mammary artery [IMA] group) received one (60 patients) or two (10 patients) IMA grafts in addition to the SVG grafts and were subjected to pleurotomy. The mean preoperative values (+/- SD) were as follows: PaO2, 75.1 +/- 7.7 mm Hg, P(A-a)O2, 20.9 +/- 7.5 mm Hg; PaCO2, 33.6 +/- 4.1 mm Hg; pH, 7.43 +/- 0.04; hemoglobin, 14.8 +/- 1.4 g/dl; and hematocrit, 44.2 +/- 3.9 percent. There was a large decrease in the PaO2 postoperatively. The nadir for the PaO2 (55.7 +/- 6.6 mm Hg) occurred on the second postoperative day. Eight days postoperatively, there were still significant abnormalities; the PaO2 was 65.7 +/- 7.3 mm Hg, the P(A-a)O2 was 33.2 +/- 8.8 mm Hg; the hemoglobin was 10.5 +/- 1.4 g/dl; and the hematocrit was 31.7 +/- 4.0 percent. The decrease in the PaO2 was particularly noteworthy given the large decrease in the hemoglobin and hematocrit. The changes in the PaO2 were not significantly correlated with the age, number of grafts, pump time, length of anesthesia, or endotracheal intubation or smoking history. Immediately postoperatively, changes were similar in both groups (p > 0.05); on the second postoperative day, the PaO2 had decreased 26.9 percent in the SVG group and 25.5 percent in the IMA group. However, the postoperative abnormalities resolved more slowly in the IMA group (p < 0.05). These observations suggest that the additional trauma to the lungs and chest wall in the IMA group (pleurotomy, the placing of pleural drains, etc) will result in a longer recovery time in the IMA group than in SVG group.

Carbon Dioxide↗

PubMed1990

Pulmonary clearance of technetium 99m diethylene triamine penta-acetic acid aerosol in patients with amiodarone pneumonitis.

Amiodarone pneumonitis is a serious complication that may lead to fatal lung fibrosis. In an attempt to diagnose this condition as early as possible, the technetium-99m-labelled diethylene triamine penta-acetic acid (99mTc-DTPA) aerosol washout rates of 10 non-smoking normal volunteers (group 1), 10 non-smoking patients on a long-term amiodarone regimen with dilated cardiomyopathy but no congestive heart failure (group II) and 10 patients with amiodarone pneumonitis (group III) were compared. Spirometric measurements, as percentage predicted, were higher in group I than in group III (P less than 0.05). The global mean effective half-lives of 99mTc-DTPA aerosol for both lungs together in minutes were 65 +/- 14, 55 +/- 16 and 27 +/- 4 for groups I, II and III, respectively. Group III values were significantly lower than those of groups I and II (P less than 0.05). Our results demonstrated that amiodarone pneumonitis alters the alveolar-capillary membrane permeability to hydrophilic molecules. The pulmonary clearance of 99mTc-DTPA aerosol is a useful test in the differentiation of patients on a long-term amiodarone regimen without side effects from patients with amiodarone pneumonitis. The test is rapid, easy to perform and has the potential for playing an important role in deciding which patients should discontinue therapy.

Aerosols↗

PubMed1989

[Pneumonitis induced by amiodarone].

Fifteen patients, eleven males and four females, with amiodarone induced pulmonary disease were studied. Their ages ranged between 52 and 79 (mean = 64.0) years. 66% of the patients were taking a daily dose of 200 mg of amiodarone. The time elapsed between the initial dose and the diagnosis of the pneumonitis varied from 2 to 84 (mean = 23.3) months. Premature ventricular beats and recurrent episodes of paroxistic supra ventricular tachycardia were the most common indications for the use of the drug. The most frequent clinical complaints were progressive dyspnea and cough. Weight loss was observed in five patients, fever in six and chest pain in two. The most habitual thoracic physical sign was diffuse crepitation. Chest roentgenograms disclosed bilateral interstitial infiltrates in all patients, associated to pleural effusions in two. An increased diffuse uptake of 67 gallium citrate was observed in the nine patients to whom it was done. Lung function tests showed a pattern of restrictive ventilatory respiratory insufficiency and hypoxemia. Lung tissue specimens were obtained in ten patients, bronchoalveolar lavage in one and pleural fluid in one. The material was examined by light and electron microscopy. Amiodarone was discontinued in all patients and corticosteroids were introduced in thirteen. Five patients (33.3%) died, eight improved and two remained with radiographic scars.

Aged↗

PubMed1986