Chemical and nonchemical stimuli during breath holding in divers are not independent.

In the breath-hold model described by S. Godfrey and E. J. M. Campbell (Respir. Physiol. 5: 385-400, 1968), chemical and nonchemical stimuli are independent. Because these two factors are time dependent, the effect of each could not be measured by breath-holding time (BHT). The aim of this study is to dissociate chemical and nonchemical stimuli and to assess the effects of BHT and PCO2 on respiratory center output by measurement of occlusion pressure (P0.1) and mean inspiratory flow (VI). Nine well-trained divers (age 36.5 +/- 5.0 yr) took part in the study. Each subject had to hold his breath at 75% of vital capacity for 30, 50, and 70 s of BHT. Before each breath hold, the subject inspired successively two vital capacities of the same CO2-O2 gas mixture. P0.1 and VI were measured during the first reinspiration after the breath hold. For the same BHT, we observed good linear relationships between P0.1 or VI and alveolar PCO2. The slopes of these relationships increased with BHT. For alveolar PCO2 of > 50 Torr, P0.1 increased linearly with BHT. These results indicate that, during breath holding, chemical and nonchemical stimuli acted linearly on respiratory motoneuron activity, but they were not independent.

[Habitat of the allergic child: theory and practice]. / Habitat de l'enfant allergique: théorie et pratique.

Control of the asthmatic child's environment forms an integral part of therapeutic care. This requires knowing what the main allergens in the child's habitat are and how they arise: eg, acarids, animal teguments, insects and fungi. The overall measures for reducing them chiefly entail controlling humidity: regular airing, or even ventilation, and eliminating sources of humidity can be recommended. Control of acarids will require modifying furnishings (no mats or carpeting, non hangings or heavy curtains, a slatted not interior spring bed base). Acarid-repellent loose covers seem to be more effective than acaricides, which give conflicting results. Physical processes, although necessary, are seldom sufficient. Animals should be evicted. If this is impossible, certain measures have proved effective, however. Insects and moulds are controlled by specific sanitary measures. A practical approach is proposed that takes into account both theoretical demands and everyday realities.

[Risk factors: environment, tobacco smoke]. / Facteurs de risque: environnement, tabac.

Environmental factors are usually considered as risk factors for increase of asthma prevalence. They may act isolately but are frequently associated. They act either directly by inducing asthma or more likely by increasing allergenic sensitization. Geographic situation is a well known risk factor. Important differences are noted between countries. The western lifestyle is evocated, including type of alimentation, small size of siblings, increased allergen exposure in houses. Intrauterine environment may play a role, particularly tobacco smoke during pregnancy and its respiratory effects on infant. Maternal allergenic exposure during pregnancy is an important factor because of maternofetal immunologic interactions. Outdoor pollution acts by enhancing bronchial responsiveness, allergenic sensitization and worsening respiratory diseases. Its effect is probably less important in infants and small children who are living indoor most of the time. Infections seems to have a complex action. Some virus, including respiratory syncytial virus, act to induce asthma or sensitization. Other type of infections (viral ou microbial) have a protector effect. Exposure to tobacco smoke, particularly maternal smoking, is identified in all studies, as one of the most important factors to be considered in childhood asthma. Exposure to allergen increases the risk of sensitization. Its direct responsibility to induce asthma is not established. Some of recent studies are suggesting the concept of a protective effect of early exposure. As far as preventive intervention is concerned, the recognition of these factors is important to limit the prevalence of childhood asthma.

[Severe streptococcal complications in varicella]. / Complications bactériennes graves à streptocoque an cours de la varicelle.

BACKGROUND: An increase in the incidence of group A beta hemolytic streptococcal (GABHS) infections in children has been recently noted with a frequent association with varicella. CASE REPORTS: Two children, 3 and 4.5 years old, developed varicella. The first one was febrile and presented a phlyctene on his left foot. Few hours after his admission, he presented a septic shock; GABHS was isolated from blood. Despite immediate adapted antibiotherapy, he developed a right tibial osteomyelitis with abscess. The second child also developed varicella and was hospitalized because of fever, bad general condition, right cervical adenitis and edema on the left wrist. Edema rapidly extended to the hand and upper arm. One purulent lesion was noted on the upper arm from whom Staphylococcus aureus and GABHS were isolated. Blood samples were sterile. The clinical course was favorable with adapted antibiotherapy. A cutaneous desquamation was observed on the 9th day and we concluded that it was a GABHS cellulitis. CONCLUSION: These two cases confirm the recent report of increase in GABHS infections associated with varicella. Such complications must be looked for in patients with varicella remaining abnormally febrile and/or presenting unusual manifestations.

[The value of procalcitonin in neonatal infections]. / Intérêt de la procalcitonine dans les infections néonatales.

UNLABELLED: The value of procalcitonin (PCT) measurement is not presently completely assessed for the diagnosis of neonatal infections. PATIENTS AND METHODS: This parameter was assessed in a prospective study in the neonatal intensive care unit of Clermont-Ferrand Hospital (France) in comparison to C-reactive protein. All newborn infants admitted before 24 h of life (day 0) in the neonatal intensive care unit were included in the study. Newborns (102) were assigned to one of four groups: group 1: non-infected newborns (n = 41); group 2: possibly infected newborns (n = 33); group 3: probably infected newborns (n = 10); group 4: confirmed infections (n = 18 bacterial or fungal infections). C-reactive protein and PCT were determined in the sera at D0, D1, D3 and D8. We determined the optimal cutoff value of PCT using the Receiver Operating Characteristic curves (R.O.C.). RESULTS: The cutoff value is 1.5 ng/mL at D0 and 10 ng/mL at D1. PCT cutoff value is significantly higher at D1 because of a significant PCT peak on the first day of life independent of any infectious stimulus. Our study shows that at D0 and D1 infected newborn infants had significantly higher mean PCT and C-reactive protein values than non infected newborn infants. C-reactive protein has a better specificity but PCT has better sensitivity and negative predictive value. CONCLUSION: PCT seems to be an interesting marker of neonatal infections especially during the first 24 h of life even though the mechanism of PCT synthesis remains unclear.

[Management of severe acute asthma in children in pediatric urgent and intensive care units]. / Prise en charge de l'asthme aigu sévère de l'enfant en unité de soins d'urgence et de soins intensifs pédiatriques.

Mortality in cases of severe asthma attacks in children is evaluated at 1%. During initial medical care, repeated evaluation of clinical and para-clinical severity criteria constitutes the main therapeutic guide. Emergency care treatment is based mainly on oxygen therapy, bronchodilatory therapy by discontinuous inhalation, and general corticotherapy. Intravenous theophylline treatment is controversial. The response after a few hours should allow a decision to be made [1] to follow up with outpatient treatment (rapid marked improvement), [2] to continue the hospital treatment (stabilization), or [3] to transfer to intensive care (worsening, exhaustion). In the intensive care unit, the treatment is based on continuous intravenous administration of beta 2 mimetics in addition to the above therapies. The objective is to avoid resorting to assisted ventilation. When this proves necessary, it must not be detrimental; controlled alveolar hypoventilation allows dynamic hyper-inflation linked to ventilation to be reduced. Prevention of relapse is indispensable. This requires hospitalization in a specialized care unit after discharge from intensive care.

[The role of lung volume measurements by plethysmography in the follow-up of asthma in children]. / Intérêt de la mesure des volumes pulmonaires par pléthysmographie corporelle dans le suivi de l'asthme de l'enfant.

In asthmatic children, control of the disease is perfect when no symptoms occur and lung function is normal. The aim of this study is to analyse the role of plethysmography in the follow-up of asthmatic children. We present the results of a retrospective study of lung function (plethysmography and forced expiratory flow) in about 100 asthmatic children aged five to 16years. FEV1/FVC less than 80% predicted was considered as pathological (airflow obstruction). The ratio RV/TLC was considered pathological if greater than 30% and RV was considered pathological if greater than 120% (lung hyperinflation). Bronchodilator reversibility was performed in all patients. All patients were studied in a stable condition. None had developed any asthmatic exacerbations during the past month. We found a significant correlation between the residual volume/total lung capacity (RV/TLC) ratio and, on one hand: FEV1 (p<0.0001, R=-0.374), and on the other hand FEV1/FVC (p=0.07, R=-0.182) or forced expiratory flow 25-75 (p=0.03, R=-0.216). When comparing children with (n=40) and without (n=60) lung hyperinflation, we noticed more diurnal symptoms (30/40 vs 10/60, p=0.05), lower weight (33.9kg vs 41.8kg, p<0.05) and lower body mass index (16.9kg/m(2) vs 18.4kg/m(2), p<0.01). Among the children with defined airway obstruction, 49% also had lung hyperinflation. Twenty-three children had normal forced expiratory ratios but an increase of the ratio RV/TLC or of RV. When compared with children without lung hyperinflation, the age at diagnosis was significantly lower (3.9+/-1.9years vs 6.2+/-3.1years, p<0.01) and weight slightly lower (31+/-10kg vs 40+/-11kg, p=0.04). In conclusion, the use of plethysmography and thus the evaluation of pulmonary hyperinflation contributed to a better appreciation of the asthmatic phenotype in children.

[Determination of nasal transepithelial potential difference (DDPTE) in cystic fibrosis. Analysis of a simplified measurement technique]. / Détermination des différences de potentiel transépithélial (DDPTE) nasal dans la mucoviscidose. Analyse d'une méthode de mesure simplifiée.

Measurements of nasal transepithelial potential differences (TEPD) were performed in 77 patients in order to assess a routine simplified method of recording. TEPD assays were performed in 34 patients with cystic fibrosis aged 1 month to 25 years, in 22 children with another chronic respiratory illness and in 21 subjects without any bronchopulmonary impairment. In the cystic fibrosis group TEPD values (mean +/- SD) were significantly higher (-49.077 +/- 9.38 mV) than in patients with chronic respiratory illnesses (-20.590 +/- 5.011 mV) or in subjects without bronchopulmonary impairment (-19.857 +/- 5.033 mV) (p less than 0.0001). Measurements could not be performed in 10 patients due to major nasal inflammation. The excellent specificity (100%) and sensitivity (93%) of the method confirm its diagnostic value. It may be used from the neonatal period and may represent an alternative to the sweat test, especially in dubious cases.