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Biomedical subjects

M Fayon

Publications and source records attributed to M Fayon.

At least 37 records · Page 2Linked to original sources

[Acute severe asthma in children. Epidemiological, physiopathological and clinical aspects].

Therapy for asthma is being prescribed more frequently. However, asthma mortality remains high in many countries. Fatal outcome is not always related to inadequate follow-up. In this article we report that children with mild to moderate symptoms may present a fatal attack. Many factors are responsible for such an outcome: asphyxia +3 due to ventilation/perfusion mismatch and/or bronchospasm, cardiac failure, cardiac arrhythmia, intrinsic positive expiratory pressure, or metabolic disturbances (hypokalemia, for example). Such problems can occur in predisposed patients: it has been shown that the chemosensitivity to hypoxia and the perception of dyspnoea are altered in certain patients with near-fatal asthma. It is very important to identify children at risk of severe asthma and to organize care so as to optimize the management of such children.

Acute Disease↗

Bacterial flora of the lower respiratory tract in children with bronchial asthma.

The aims of this retrospective study were to (i) determine the risk of contamination of lower respiratory tract samples obtained during fiberoscopy in children; (ii) determine the incidence and profile of the bacterial flora of the lower respiratory tract in a selected group of asthmatic children at high risk for bacterial infection; and (iii) identify risk markers for such findings. In 29 asthmatic children, comparison of bacterial cultures of specimens obtained from the upper and, lower respiratory tracts showed that contamination was a possibility in only 3.4% (1/29) of cases. The results from bacterial samples obtained via flexible bronchoscopy in a further 273 consecutively investigated physician-diagnosed asthmatic children were analysed. Patients were selected for bronchoscopy if they had severe chronic asthma or in order to exclude other diseases able to provoke wheezing. Their mean (SD) and median ages were 32.2 (38.3) and 17.5 mo, respectively. The incidence of positive bacterial cultures was 12.1% (33/273 patients). Bacterial flora included H. influenzae (39.5%, 15/38), B. catarrhalis (23.7%, 9/38), Neisseria species (7.9%, 3/38), M. pneumoniae (7.9%, 3/38), P. non-aeruginosa (5.3%, 2/38) and P. aeruginosa (2.6%, 1/38). No clinical or radiological markers were significantly associated with lower respiratory tract bacterial infection. Large quantities of bacteria were present in the lower respiratory tracts of a substantial number of children (1/8) in this selected group of asthmatics. For the moment, however, the clinical implications of this finding remain unclear.

Asthma↗

Abdominal lymphatic dysplasia and 22q11 microdeletion.

We report the case of a child with 22q11 microdeletion who presented with abdominal lymphatic dysplasia resulting in exsudative enteropathy. This primitive and localized lymphatic malformation is consistent with the vascular theory in the velocardiofacial syndrome.

Chromosome Deletion↗

[Severe community-acquired pneumonia in immunocompetent children].

Severe community-acquired pneumonia (CAP) is still a serious disease with a high mortality rate, especially in developing countries. Children under 5 years are more prone to severe CAP. In this article, the authors review the definition and clinical criteria used in the initial evaluation and decision to hospitalize patients. The diagnosis approach requires only a limited number of laboratory tests before initiating the supportive measures and wide spectrum antimicrobial therapy. If the patient fails to respond favorably 48-72 hours after initiating therapy, more invasive investigations are indicated. After resolution, an immunological evaluation is warranted.

Child↗

Rhabdomyolysis in European viper bite.

The case of a child who presented with severe rhabdomyolysis associated with renal failure after a viper bite is reported. Rhabdomyolysis is a serious complication resulting from systemic envenomation and is uncommon after viper bites in Europe. It may be due to oedema, myotoxic agents and haemorrhagic factors and may be responsible for two types of potentially fatal complications, i.e. acute renal failure and hyperkalaemia. The present case highlights the need to investigate routinely for rhabdomyolysis after viper bites. Antivenom therapy is recommended as soon as signs of envenomation are present, without waiting for the onset of complications.

Animals↗

Oesophageal atresia, VACTERL association: Fanconi's anaemia related spectrum of anomalies.

Oesophageal atresia usually occurs without any genetic background. Three cases associated with Fanconi's anaemia are reported. One neonate had growth retardation and numerous malformations including oesophageal atresia and four other components of the VACTERL association. In the two others, oesophageal atresia was isolated. In patients with such malformations an early diagnosis of Fanconi's anaemia may have important genetic and therapeutic implications.

Esophageal Atresia↗

Epidemiology of sepsis and multiple organ dysfunction syndrome in children.

STUDY OBJECTIVES: To determine the cumulated incidence and the density of incidence of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, and multiple organ dysfunction syndrome (MODS) in critically ill children; to distinguish patients with primary from those with secondary MODS. DESIGN: Prospective cohort study. SETTING: Pediatric ICU of a university hospital. PATIENTS: One thousand fifty-eight consecutive hospital admissions. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: SIRS occurred in 82% (n=869) of hospital admissions, 23% (n=245) had sepsis, 4% (n=46) had severe sepsis, 2% (n=25) had septic shock; 16% (n=168) had primary MODS and 2% (n=23) had secondary MODS; 6% (n=68) of the study population died. The pediatric risk of mortality (PRISM) scores on the first day of admission to pediatric ICU were as follows: 3.9 +/- 3.6 (no SIRS), 7.0 +/- 7.0 (SIRS), 9.5 +/- 8.3 (sepsis), 8.8 +/- 7.8 (severe sepsis), 21.8 +/- 15.8 (septic shock); differences among groups (p=0.0001), all orthogonal comparisons, were significant (p<0.05), except for patients with severe sepsis. The observed mortality for the whole study population was also different according to the underlying diagnostic category (p=0.0001; p<0.05 for patients with SIRS and those with septic shock, compared with all groups). Among, patients with MODS, the difference in mortality between groups did not reach significance (p=0.057). Children with secondary MODS had a longer duration of organ dysfunction (p<0.0001), a longer stay in pediatric ICU after MODS diagnosis (p<0.0001), and a higher risk of mortality (odds ratio, 6.5 [2.7 to 15.9], p<0.0001) than patients with primary MODS. CONCLUSIONS: SIRS and sepsis occur frequently in critically ill children. The presence of SIRS, sepsis, or septic shock is associated with a distinct risk of mortality among critically ill children admitted to the pediatric ICU; more data are needed concerning children with MODS. Secondary MODS is much less common than primary MODS, but it is associated with an increased morbidity and mortality; we speculate that distinct pathophysiologic mechanisms are involved in these two conditions.

Adolescent↗

Respiratory mechanics before and after late artificial surfactant rescue.

OBJECTIVE: To assess the effect of late administration of synthetic surfactant (Exosurf) on the ventilatory function of premature infants with hyaline membrane disease (HMD). METHODOLOGY: Prospective non-randomized study in the Neonatal Intensive Care Unit (NICU) of a major referral hospital. The patients included two groups of premature infants with a birthweight between 750 and 2000 g who developed HMD. In group 1 with moderate to severe HMD, 2 x 5 mL/kg doses of Exosurf were given 12 h apart (first dose given at a mean age of 18.7 +/- 3.4 h [mean +/- s.e.m.]). In group 2 with milder HMD, no surfactant was given. RESULTS: Significant reductions (P < 0.05) in the fraction of inspired oxygen (FIO2) occurred 6 h after surfactant administration (24 h of life) and by 48 h (64 h of life) in group 2. These improvements in gas exchange preceded improvements in passive respiratory compliance which occurred 24 h after surfactant (42 h of life) and by 72 h (88 h of life) in group 2 (P < 0.01). In both groups pulmonary resistance increased and was significant (P < 0.05) by 48 h (66 h of life) in group 1. CONCLUSIONS: Synthetic surfactant given as late as a mean age 18.7 +/- 3.4 h still improves gas exchange but these early improvements cannot be completely explained by modifications of respiratory compliance.

Age Factors↗

Pulmonary mechanics in ventilated preterm infants with respiratory distress syndrome after exogenous surfactant administration: a comparison between two surfactant preparations.

The effects of two surfactant preparations on lung mechanics have been studied on 24 ventilated premature infants with respiratory distress syndrome (RDS): 13 were given artificial surfactant (Exosurf Neonatal, Burroughs-Wellcome) and 11 natural porcine surfactant (Curosurf, Laboratoire Serono France). Measurements of respiratory system compliance (Cdyn, Crs) and resistance (Rrs) were performed immediately before surfactant administration and repeated 6, 18, 24, 48, and 72 hours later. With Exosurf treatment, 6 hours after surfactant administration inhaled O2 concentration (FlO2) could be lowered from (0.72 +/- 0.20, to 0.62 +/- 0.33; P < 0.05), whereas Crs did not change (0.37 mL/cmH2O/kg, +/- 0.14 vs. 0.39 +/- 0.12, NS). After 24 hours and during the following days a significant increase in Crs occurred (24 hours post-Exosurf: 0.51 +/- 0.18, P < 0.05). With Curosurf treatment, the improvement in oxygenation was greater and FlO2 could be lowered much more after 6 hours (from FlO2, 0.78 +/- 0.23 to 0.34 +/- 0.11, P < 0.01). This was associated with an increase in Crs (from 0.39 +/- 0.09 to 0.59 +/- 0.17, P < 0.05). During the following days, Crs was significantly higher in the group treated with Curosurf. Resistance was not altered by the type of surfactant preparation used except after 72 hours, when Rrs increased in the group treated with Exosurf. In conclusion, Curosurf appears to be more effective than Exosurf with regard to immediate pulmonary changes in ventilator treated premature infants with RDS. A rapid increase in Crs after Curosurf treatment indicates that recruitment of new functional areas of the lung is likely to be associated with a stabilization of small airways and alveolar units.

Airway Resistance↗

Human airway smooth muscle responsiveness in neonatal lung specimens.

The mechanical activity of proximal airways isolated from human lung specimens obtained at autopsy from 11 neonates was studied in response to the following compounds: carbachol, histamine, potassium chloride (KCl), neurokinin A (NKA) (both in the presence and in the absence of the neutral endopeptidase inhibitor phosphoramidon) and isoproterenol. Isometric responses to the various concentrations of each of the compounds were expressed as both raw values of force normalized to smooth muscle cross-sectional area (SMCSA), i.e., muscle stress and percentages of the maximal response to acetylcholine. Maximal active muscle stress of human neonatal bronchi was induced by carbachol and averaged 95 +/- 25 mN/mm2 SMCSA (n = 8). The rank of maximal force induced by the contractile agonists was carbachol > histamine > KCl > NKA, and the rank of the concentration of drug producing one-half of the maximum effect (EC50) was NKA < carbachol < histamine < KCl. The EC50 value for isoproterenol was the lowest, although it generated the smallest mechanical response. When compared with results obtained under identical experimental conditions in the human adult lung, except for carbachol and isoproterenol, general trends were an increase in force generation with age and little changes in EC50 values. There was a decrease in carbachol-induced force with age, whereas the opposite was observed with isoproterenol. We conclude that most of the mechanisms that control airway tone in humans are already present in the neonate. Alterations in the response to agonists with the maturational process may have implications in the pharmacologic modulation of bronchial obstruction in neonates.

Carbachol↗