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Biomedical subjects

B Aguilaniu

Publications and source records attributed to B Aguilaniu.

At least 19 recordsLinked to original sources
PubMed2006

Positional hyperventilation-induced hypoxaemia in pectus excavatum.

The presented case is of a young male (aged 19 yrs) with a pectus excavatum who showed significant exercise intolerance, despite normal pulmonary function at rest, including carbon monoxide diffusing capacity. Clinical exercise testing led to a strong suspicion of a right-to-left shunt due to an abnormally wide alveolo-arterial oxygen gradient (26.4 kPa) at peak oxygen uptake, with severe arterial hypoxaemia (arterial oxygen tension 12.54 kPa). A right-to-left shunt was confirmed by transoesophageal echocardiography demonstrating a permeable foramen ovale, despite normal right heart pressures. The right-to-left venous flow was mainly dependent on the upright body position and the deep inspiration. Indeed, i.v. dobutamine infusion to selectively affect cardiac output and hyperventilation induced by tidal volume expansion at constant breathing rate in the supine position did not result in arterial oxygen desaturation or shunting. Closure of the foramen ovale through atrial umbrella placement dramatically improved clinical and physiological abnormalities. This observation demonstrates that a hyperventilatory manoeuvre in the upright position is able to detect a permeable foramen ovale favouring flow in the inferior vena cava in the direction of the abnormal pre-existing atrial channel in a patient with a pectus excavatum.

Adult↗
PubMed2005

The effect of tiotropium on hyperinflation and exercise capacity in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, which results in the progressive development of dyspnea and exercise limitation. OBJECTIVE AND METHODS: To compare the effect of tiotropium with placebo on forced vital capacity (FVC) in patients with moderate-to-severe COPD and lung hyperinflation, using exercise endurance, dyspnea and health-related quality of life (HRQoL) as secondary endpoints. One hundred patients were randomized to receive either tiotropium 18 mug once daily or placebo for 12 weeks. RESULTS: Trough (predose) FVC was significantly improved with tiotropium compared to placebo on day 42 (0.27 +/- 0.08 liters) and 84 (0.20 +/- 0.08 liters; p < 0.05 for both). Trough inspiratory capacity (IC) was also significantly improved with tiotropium compared to placebo on day 42 (0.16 +/- 0.07 liters) and 84 (0.15 +/- 0.07 liters; p < 0.05 for both). Tiotropium increased the mean distance walked during the shuttle walking test by 33 +/- 12 (day 42) and 36 +/- 14 m (day 84) compared to placebo (p < 0.05 for both). On day 84, 59% of the patients in the tiotropium group and 35% of the patients in the placebo group had significant and clinically meaningful improvements in the St. George's Respiratory Questionnaire total score (p < 0.05). Numerical decreases in the focal score in the Transition Dyspnea Index in patients receiving tiotropium versus placebo suggest that tiotropium also improved dyspnea during activities of daily living. CONCLUSION: Tiotropium 18 mug once daily reduced hyperinflation with consequent improvements in walking distance and HRQoL in patients with COPD and lung hyperinflation.

Adult↗
PubMed2004

Effects of tiotropium on lung hyperinflation, dyspnoea and exercise tolerance in COPD.

The aim of this study was to test the hypothesis that use of tiotropium, a new long-acting anticholinergic bronchodilator, would be associated with sustained reduction in lung hyperinflation and, thereby, would improve exertional dyspnoea and exercise performance in patients with chronic obstructive pulmonary disease. A randomised, double-blind, placebo-controlled, parallel-group study was conducted in 187 patients (forced expiratory volume in one second 44 +/- 13% pred): 96 patients received 18 microg tiotropium and 91 patients received placebo once daily for 42 days. Spirometry, plethysmographic lung volumes, cycle exercise endurance and exertional dyspnoea intensity at 75% of each patient's maximal work capacity were compared. On day 42, the use of tiotropium was associated with the following effects at pre-dose and post-dose measurements as compared to placebo: vital capacity and inspiratory capacity (IC) increased, with inverse decreases in residual volume and functional residual capacity. Tiotropium increased post-dose exercise endurance time by 105 +/- 40 s (21%) as compared to placebo on day 42. At a standardised time near end-exercise (isotime), IC, tidal volume and minute ventilation all increased, whilst dyspnoea decreased by 0.9 +/- 0.3 Borg scale units. In conclusion, the use of tiotropium was associated with sustained reductions of lung hyperinflation at rest and during exercise. Resultant increases in inspiratory capacity permitted greater expansion of tidal volume and contributed to improvements in both exertional dyspnoea and exercise endurance.

Aged↗
PubMed2002

Early onset of pulmonary gas exchange disturbance during progressive exercise in healthy active men.

Some recent studies of competitive athletes have shown exercise-induced hypoxemia to begin in submaximal exercise. We examined the role of ventilatory factors in the submaximal exercise gas exchange disturbance (GED) of healthy men involved in regular work-related exercise but not in competitive activities. From the 38 national mountain rescue workers evaluated (36 +/- 1 yr), 14 were classified as GED and were compared with 14 subjects matched for age, height, weight, and maximal oxygen uptake (VO2 max; 3.61 +/- 0.12 l/min) and showing a normal response (N). Mean arterial PO2 was already lower than N (P = 0.05) at 40% VO2 max and continued to fall until VO2 max (GED: 80.2 +/- 1.6 vs. N: 91.7 +/- 1.3 Torr). A parallel upward shift in the alveolar-arterial oxygen difference vs. %VO2 max relationship was observed in GED compared with N from the onset throughout the incremental protocol. At submaximal intensities, ideal alveolar PO2, tidal volume, respiratory frequency, and dead space-to-tidal volume ratio were identical between groups. As per the higher arterial PCO2 of GED at VO2 max, subjects with an exaggerated submaximal alveolar-arterial oxygen difference also showed a relative maximal hypoventilation. Results thus suggest the existence of a common denominator that contributes to the GED of submaximal exercise and affects the maximal ventilatory response.

Adult↗
PubMed2001

[Cardiac metastasis from a Merkel cell skin carcinoma. A case report].

The authors report the case of a cardiac metastasis of a Market cell skin tumour in a 72 year old woman, presenting with chest pain and infero-lateral myocardial ischaemia simulating an acute coronary syndrome. The diagnosis, suspected on echocardiography, was confirmed by thoracic CT scan. Markel cell carcinoma is a rare skin tumour classified among the malignant neuroendocrine tumours. It has a high metastatic potential, especially to the gastrointestinal tract and the lung. On the other hand, cardiac metastases are quite exceptionally rare.

Aged↗
PubMed1998

Effects of indomethacin and polyunsaturated fatty acid diet on exercise-induced hypoxaemia in master athletes.

We have previously reported a reduction in exercise-induced hypoxaemia following polyunsaturated fatty acid supplementation (PUFA). Although this might have been explained by increases in membrane fluidity, a clear explanation could not be provided due to potentially confounding influences of series-2 prosta- glandin mediated effects resulting from PUFA. In this investigation, ten master athletes [mean age 48.1 (SEM 6) years, maximal oxygen uptake (VO2max) 3.39 (SEM 0.21) l x min(-1)] completed a maximal cycling test (Ctrl) which was repeated after the administration of 150 mg of indomethacin to inhibit prostaglandin synthesis, both before and after 6 weeks of 3.66-g PUFA x day(-1). Cardiorespiratory parameters were obtained simultaneously with brachial arterial blood sampling for partial pressure of oxygen in arterial blood (PaO2), partial pressure of carbon dioxide in arterial blood (PaCO2), pH, oxygen saturation in arterial blood and lactate concentration determinations. A significant decrease in PaO2 (mmHg) from rest [93 (SEM 1.5)] was observed for exercise intensities of more than 40% VO2max in Ctrl reaching 75.9 (SEM 2.1) at VO2max. PUFA resulted in a 5.0 (SEM 0.68) mmHg upward shift (P < 0.05) in the PaO2-oxygen uptake relationship, reducing the difference in partial pressure of oxygen between alveolar air and arterial blood (P(A-a)O2) at VO2max [Ctrl 36 (SEM 1.6) vs PUFA 33 (SEM 2.2) mmHg] while PaCO2, remained unchanged. Indomethacin had no effect on either PaO2, ideal partial pressure of oxygen in alveolar gas or P(A-a)O2 in either Ctrl or after PUFA. In contrast, the fall in pH was significantly reduced after indomethacin while VCO2, PaCO2 and lactacidaemia remained unchanged. These observations confirm an effect of PUFA on exercise PaO2 behaviour which does not appear to be mediated by the influence of a series-2 prostaglandin.

Adult↗
PubMed1998

[Diagnostic use of oxygen consumption and gas exchange in exercise testing].

The interpretation of cardio-pulmonary exercise testing is usually performed on successive decisional organigrams which are based on the normality of two initial main branchpoints i.e., Vo2max and ventilatory threshold (VThr). This didactic approach leads however to a simplistic approach of exercise pathophysiology because the answer to the two original branchpoints (Vo2max and VThr) is mainly binary whereas the physiological meaning of these two parameters is multifactorial. Thus, we propose a methodic analytical approach which allows to integrate step by step the various informations concerning aerobic capacity, ventilatory and cardiocirculatory responses, and acidobasic status. After a purely descriptive analysis of data , a first synthesis describes the physiopathological behaviour during exercise and states the specificity of these informations excluding usual confounding factors. The comparison between the functional data and the clinical informations allows to propose some physiopathological hypothesis by confronting several complementary approaches: physiological, physiopathological and clinical ones. This method seems to be more adapted to the clinical diagnostic use of such a physiological investigation because it is sensitive, reproducible but not specific.

Data Interpretation, Statistical↗
PubMed1996

Cardiac output response to dynamic exercise after atrial switch repair for transposition of the great arteries.

Results from this study showed that patients who underwent successful operation for transposition of the great arteries had no appropriate increase in stroke volume in response to exercise of a nature similar to common recreational activities. The impairment, most likely due to disturbances in both venous return and ventricular systolic function, is compensated for by an increase in peripheral oxygen extraction; however, this increase may not be adequate with maturation or during prolonged exercise when cardiovascular constraints are more important.

Cardiac Output↗
PubMed1996

[Cardiac output evaluation during exercise in children treated with atrial surgery for transposition of great vessels].

The long-term physiopathological consequences of atrial surgery (Senning or Mustard procedures) for transposition of the great vessels with respect to exercise capacity are not well known. We measured the cardiac index by the technique of CO2 rebreathing at two submaximal levels of exercise corresponding to a stable oxygen consumption of 20 (E20) and 30 (E30) ml/min/kg in 7 patients successfully operated for transposition of the great vessels and in 7 control children paired for age, gender and body surface area. Despite an identical chronotropic response to exercise in the two groups, the increase in cardiac index was not as great in the children operated for transposition (from 6.86 +/- 0.51 to 7.71 +/- 0.78 l/min/m2) as in the control population (from 7.71 +/- 0.78 to 10.2 +/- 0.51 l/min/m2; p < 0.02). The stroke volume index was therefore significantly lower in the transposition group at both levels of exercise (52 +/- 3.2 vs 63 +/- 4.1 ml/m2; p < 0.04 at E20; and 46.4 +/- 4.3 vs 66 +/- 5.1 ml/m2 at E30). The main cause of this reduction of the stroke volume index is probably a lack of adaptation of right ventricular systolic function on exercise but it is not possible to exclude diastolic dysfunction due to reduce compliance secondary to the intraatrial patch. The conditions of preload are in fact instrumental in increasing stroke volume index at submaximal exercise levels.

Adaptation, Physiological↗
PubMed1995

Exercise-induced hypoxaemia in master athletes: effects of a polyunsaturated fatty acid diet.

Exercise-induced hypoxaemia (EIH) has been associated with an oxygen diffusion limitation. Because polyunsaturated fatty acids (PUFA) administration can modify cell membrane fluidity, we hypothesized that the importance of EIH could be reduced after a 6-week PUFA diet. Resting pulmonary functions and a maximal cycling test were performed before and after the diet, in eight master athletes -48 (SD 6 years)-. The partial pressure of O2 in arterial blood (PaO2), alveolar ventilation (VA) and ideal alveolar-arterial oxygen partial pressure difference (P(Ai-a) O2) were obtained at each exercise intensity. The extent of EIH at maximal exercise was significantly lower after PUFA [PaO2-17.2 (SEM 1.9) vs -12.9 (SEM 2.2)]. Before PUFA, VA accounted for 50% of the variance in the fall in P (Ai-a) for intensities below 80% maximal oxygen uptake (VO2max) and P(Ai-a)O2 for 60% between 70% and 100% VO2max. After PUFA, the reduction in EIH was highly correlated (r2 = 0.85; P < 0.001) to resulting changes in P(Ai-a)O2 and resting pulmonary diffusing capacity (DLCO)/VA but not with changes in ideal alveolar partial pressure of oxygen. The improvement in EIH following PUFA could be related to an increase in alveolar-arterial oxygen conductance following improved pulmonary diffusion.

Adult↗
PubMed1993

[Cardiorespiratory and metabolic changes during prolonged exercise at 50% of the maximal load. Application to rehabilitation of severe cardiac insufficiencies].

The object of physical training in patients with chronic cardiac failure and severe left ventricular dysfunction is to improve skeletal muscle adaptation without impairing myocardial function. It is acknowledged that aerobic exercise limits increased ventricular strain. Therefore, the authors decided to determine whether exercise at 50% maximal power load constituted aerobic training. Eight patients with chronic cardiac failure (age 57 +/- 10 years; resting radionuclide ejection fraction: 25 +/- 5%) performed a rectangular submaximal exercise for 20 minutes at 50% of maximal aerobic load (MAL) as determined by a prior triangular exercise test at 10 W/mn (MAL = 92 +/- 26 Watts-Peak VO2 = 14.8 +/- 2.4 ml/Kg/mn). Gaseous exchanges (VO2, VCO2) minute volume (MV) and serum lactates were measured at rest and every 5 minutes during exercise. MV, VO2 and VCO2 increased significantly (p < 0.005) with a change of less than 5% between the 20th and 10th minute. Respiratory quotient was unchanged until the end of exercise and serum lactate levels stabilised between the 10th (3.4 +/- 0.66 mmol/l) and the 20th minute of exercise (3.5 +/- 0.47 mmol/l). No significant relationship was observed between ventilation and serum lactate or between respiratory quotient and serum lactate. These results confirm that exercise at 50% of maximal load is aerobic training even in patients with severe left ventricular dysfunction. This parameter would appear to be more useful than using the heart rate which is often abnormal in chronic cardiac failure (abnormal chronotropic response, atrial or ventricular arrhythmias).

Aerobiosis↗
PubMed1993

Effect of double-blind crossover selenium supplementation on biological indices of selenium status in cystic fibrosis patients.

Twenty-seven cystic fibrosis patients received selenium supplementation (2.8 micrograms of sodium selenite per kilogram of body weight per day) or a placebo. This 5-month trial was conducted as a double-blind, placebo-controlled study. After an interval of 2 months, treatments of the two groups were interchanged (crossed over) for another 5-month period. A group of healthy subjects, living in the same area, was investigated simultaneously. No selenium deficiency was found either in plasma or in erythrocytes before the supplementation. This result was inconsistent with a previous study performed in 1988 in our laboratory. This change in selenium status can be explained by progress in the nutritional nursing care of children and by the addition of selenium to the diet. During the study, selenium concentrations in plasma decreased when patients received placebo treatment and increased during selenium intake. In one of the two groups a similar variation was found for glutathione peroxidase activities in plasma and erythrocytes, whereas erythrocyte selenium was normal and did not change in any group. Nowadays, in the Grenoble area, the selenium status of cystic fibrosis patients is close to normal. Nevertheless, this study indicates a fragile equilibrium, given that selenium concentrations cn be lowered by placebo or mildly increased by supplementation.

Adolescent↗