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Biomedical subjects

P Lebecque

Publications and source records attributed to P Lebecque.

51 records · Page 3Linked to original sources
PubMed1991

Measurement of respiratory system resistance by forced oscillation in normal children: a comparison with spirometric values.

In 377 children, the commercially available Siregnost FD-5 was used to measure respiratory system resistance (Rrs) by forced oscillation at 10 Hz. The children were between 3 and 18 years of age and, by a detailed questionnaire and conventional pulmonary function testing in 335, they were shown to be representative of the normal pediatric population. There was a linear relationship between Rrs and height (Rrs = 13.9-0.064 x ht (cm), r = -0.87). Children less than 6 years of age had no trouble with using the forced oscillation technique. The smoking of tobacco in the house, the presence of carpets in the child's bedroom, or an atopic family history, alone or in combination, had no influence on Rrs or on any spirometric measure. Forced oscillation is useful in children too young to be able to cooperate with conventional pulmonary function testing.

Adolescent↗
PubMed1991

Pulse oximetry versus measured arterial oxygen saturation: a comparison of the Nellcor N100 and the Biox III.

Pulse oximetry is noninvasive, fast, and simple, making it a very popular way of assessing oxygenation in pediatric patients. However, there are few studies that establish the accuracy of this technology over a wide range of oxygen saturations in children. This study, done in 47 children aged from 1 day to 16 years with congenital heart disease and undergoing cardiac catheterization, compared the direct measurement of arterial oxygen saturation to values from pulse oximetry. Oxygen saturation was measured by an IL-282 Co-oximeter, which also measured carboxyhemoglobin and methemoglobin, and was compared to values obtained from both a Biox III and Nellcor N100. Both pusle oximeters gave values that closely correlated with the actual saturation (r = 0.91 and 0.93, respectively) with standard errors of the estimate of 4.1 and 3.2%, respectively. For both devices, the error increased with decreasing saturations, being progressively larger below a saturation of 80%. The difference between the actual saturation and that measured by pulse oximetry bore no relationship to the presence of carboxyhemoglobin, methemoglobin, fetal hemoglobin, bilirubin, cardiac index, or age of the patient. In conclusion, pulse oximetry, while a very useful technology in pediatrics, must be interpreted with some caution in children with severe cyanosis.

Adolescent↗
PubMed1988

Effect of molsidomine on the lung diffusing capacity of normal men.

Molsidomine (M) is a new antianginal drug which induces a peripheral venous pooling and decreases pulmonary artery and pulmonary venous pressures. The purpose of our study is to assess whether M influences the filling of the pulmonary capillary bed as estimated by the single-breath lung diffusing capacity (DLCO). DLCO was measured before and 10, 20, 30, 40, 50 and 60 minutes after sublingual administration of 2 mg molsidomine in six healthy men examined in sitting and supine positions. The blood flow distribution was estimated by means of radioactive xenon, in sitting position only, before and 30 minutes after M intake. M. induces a significant fall in DLCO from the 20th to the 60th minute which indicates an emptying of the pulmonary capillary bed. Concomitantly, blood flow is redistributed from the apices to the lung bases. We explain the decrease in DLCO by two mutually non-exclusive mechanisms: an outflow of the blood from the thorax to the periphery and a change in the lung-perfusion distribution. From a practical point of view, two conclusions may be reached. First, in coronary patients a decrease in DLCO and DLCO/VA may be due to the intake of vasodilating agents such as molsidomine and not to emphysema or lung fibrosis. Secondly, the measurement of DLCO is a useful tool to assess the action of a drug on the pulmonary circulation.

Adult↗
PubMed1987

Diffusion capacity and oxygen desaturation effects on exercise in patients with cystic fibrosis.

Although a fall in arterial oxygen saturation (SaO2) during exercise has been reported in patients with advanced lung disease due to cystic fibrosis (CF), not every patient with advanced disease desaturates, and pulmonary function tests have not been considered predictive as to which patient will desaturate. This study evaluated oxygen desaturation by ear oximetry during a progressive exercise test in 21 patients with CF and compared it to forced expiratory volume in one second (FEV1), the forced vital capacity (FVC) and the single breath diffusing capacity for carbon monoxide (DCO), all expressed as percent predicted. During exercise, the SaO2 fell less than 0.25 percent per ml of the maximal O2 consumption per kilogram of body weight to values never less than 90 percent in 15 patients (group A), whereas it fell more than this and always to values at the end of exercise of less than 90 percent in six others (group B). The FEV1 ranged from 103 percent predicted to 37 percent for group A compared to 28 to 17 percent in group B, while the range of FEV1/FVC was 87 to 52 percent for group A and 54 to 40 percent for group B. The range of DCO for group A was 129 to 84 percent compared to 64 to 54 percent. In conclusion, this study found that both the FEV1 and the DCO could separate those that had significant desaturation from those that did not and that no patient with a DCO of 80 percent or greater had significant desaturation during exercise.

Adolescent↗
PubMed1987

Histamine challenge test in children using forced oscillation to measure total respiratory resistance.

This study analyzed the relationship between total respiratory resistance (Rrs) measured by forced oscillation technique and FEV1 during histamine provocation test in 31 children between seven and 17 years of age. Rrs was measured at frequencies between 6 (R6) and 26 Hz (R26). (R6-R26)/R26 was used as an index of frequency dependency of Rrs. A positive histamine test was defined as PC20 less than 8 mg/ml. Seventeen subjects had a positive test, and all of these had increases from baseline of R6 greater than 50 percent and (R6-R26)/R26 greater than 0.45. Of the 14 subjects whose PC20 was greater than 8 mg/ml, only two had changes in R6 and (R6-R26)/R26 of this magnitude. These two subjects had changes in FEV1 of 16 and 18 percent. There was a strong linear relationship between the changes in FEV1 and both R6 and (R6-R26)/R26 from baseline to the final value at the end of the test (r = 0.87 and 0.91 respectively). In conclusion, this study demonstrated that the evaluation of airway reactivity by histamine challenge may be done by forced oscillation technique. It is easy to administer and may allow testing of children unable to perform spirometry.

Adolescent↗
PubMed1986

Hysteresis of the alveolar capillary membrane in normal subjects.

Weibel and associates (Respir. Physiol. 18: 285-308, 1973), using morphometric techniques, demonstrated in the rat that changes in lung volume related to inflation and deflation caused a hysteretic variation in alveolar capillary membrane which is locally pleated at low pulmonary volume, unfolds during inflation but does not immediately refold during deflation, possibly enhancing the CO diffusion throughout the membrane. The present study was conducted to verify the existence of this hysteresis in human lungs in vivo. Single-breath diffusing capacity for CO (DLCO) was measured in five healthy seated subjects before and 0, 0.5, 1, 3, and 7 min after an inflation-deflation maneuver (IDM) in 6 separate days. The value of mean DLCO was 36.4 +/- 3 (SD) before and 42.1 +/- 2.9, 41.6 +/- 3.3, 40.3 +/- 3.3, 39.2 +/- 3.2, and 38.1 +/- 2.7 ml X min-1 X Torr-1 after the IDM. Two mechanisms can explain our findings: an active filling of the capillary bed, or an unfolding of the alveolar capillary membrane. The first mechanism should be accompanied by changes in pulmonary circulation. Therefore, right-heart catheterization was performed in two normal subjects and in four patients examined for a chest pain syndrome. At the end of the IDM, the values for the pulmonary artery pressure and capillary wedge pressure had returned to control levels. This suggests that the capillary bed is not directly involved in the DLCO increase observed from 0.5 to 7 min after the IDM. The unfolding of the alveolar capillary membrane appears to better explain our findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Volume↗
PubMed1985

Fatal meningitis due to multi-resistant Haemophilus influenzae type b.

We report the case of a 3-month-old boy suffering from an acute bacterial meningitis due to a multi-resistant strain of Haemophilus influenzae type b. Also presented is our current strategy of treatment and chemoprophylaxis of Haemophilus influenzae meningitis in children.

Ampicillin↗
PubMed1985

[Bronchogenic cysts of the mediastinum in children. Apropos of 14 cases].

Fourteen children, aged from 2 months to 14 years, underwent surgical excision of a bronchogenic cyst in the mediastinum. Nine of these children were asymptomatic and the finding of the tumor was purely accidental. Retrotracheal and subcarinal localizations were more often symptomatic but their visualization on standard chest roentgenograms was sometimes difficult. An oesophagogram was helpful for the diagnosis in those circumstances. No postoperative complication occurred in our series.

Adolescent↗
PubMed1985

[Subpleural lipoma in children].

Primary extrapleural intrathoracic tumors are extremely rare in the pediatric patient. The authors report one observation of intrathoracic subpleural lipoma in five-year-old asymptomatic girl. A thoracic CT-Scan was particularly helpful by demonstrating the homogeneous fatty nature of the mass, the density of-120 Hounsfield Units being specific. This allowed us to limit ourselves to a brief non-invasive diagnostic workup. Complete surgical excision is curative and provides histological certainty about the benign nature of the tumour. It remains the current recommended approach.

Child, Preschool↗
PubMed1984

Myxomatous degeneration of the mitral valve in a child with Turner syndrome and partial anomalous pulmonary venous return.

This a report of myxomatous mitral valve degeneration in a child with Turner syndrome. The diagnosis was first suspected at 7 months of age. At 5 years of age, ultrasonic and angio-cardiographic confirmation prompted a successful mitral valve replacement with a Starr prosthesis. The child also had partial anomalous pulmonary venous return and a dysplastic right kidney. The child has remained well for 4 years after surgery.

Diagnosis, Differential↗
PubMed1983

The wandering spleen.

The article presents two cases of wandering spleen in the pediatric age group. Both patients were admitted for abdominal pain. In one, the onset was sudden and, on physical examination, a mass was felt in the left hypochondrium. In the other, it was the second episode and a firm mid-abdominal mass was found. The wandering spleen is a specific clinical syndrome which should be taken into account when an abdominal tumor is found. Ultrasonography and isotopic scan are very useful diagnostic tools The wandering spleen is caused by the absence of the splenorenal ligament which allows increased mobility of the splenic hilum. Both children underwent a splenectomy and made an uneventful recovery.

Abdominal Neoplasms↗