Chronic stridor caused by laryngomalacia in children: work of breathing and effects of noninvasive ventilatory assistance

Breathing pattern, gas exchange, and respiratory effort were assessed in five awake children with chronic stridor caused by laryngomalacia during spontaneous breathing (SB) and noninvasive mechanical ventilation (NIMV). During SB, the youngest children were able to maintain normal gas exchange at the expense of an increased work of breathing as assessed by calculated diaphragmatic pressure-time product (PTPdi), whereas the opposite was observed in the older children. NIMV increased tidal volume, from 8.77 +/- 2.04 ml/kg during SB to 11.67 +/- 2.52 ml/kg during NIMV, p = 0.04, and decreased respiratory rate, from 24.4 +/- 5.6 breaths/ min during SB to 16.6 +/- 0.9 breaths/min during NIMV, p = 0.04. NIMV unloaded the respiratory muscles as reflected by the significant reduction in PTPdi, from a mean value of 541.0 +/- 196.6 cm H(2)O x s x min(-1) during SB to 214.8 +/- 116.0 cm H(2)O x s x min(-1) during NIMV, p = 0.04. Therefore, NIMV successfully relieves the additional load imposed on the respiratory muscles. Long-term home NIMV was provided to a total of 12 children with laryngomalacia (including these five) and was associated with clinical improvement in sleep and growth.

Temporal generalization in 3- to 8-year-old children

Children aged 3, 5, and 8 years were tested on temporal generalization with visual stimuli. Different groups received 4- and 8-s standards. Gradients at all ages superimposed when plotted on the same relative scale, indicating underlying scalar timing. The principal developmental changes were (i) increasing sharpness of the generalization gradient with increasing age and (ii) a change from symmetrical (3 and 5 years) to adultlike asymmetrical generalization gradients in the oldest children. Theoretical modeling attributed these changes to increasing precision of the reference memory of the standard with increasing age, as well as a decreased tendency to "misremember" the standard as being shorter than it actually was, as the children developed.

In vivo physiologic comparison of two ventilators used for domiciliary ventilation in children with cystic fibrosis

OBJECTIVE

Home noninvasive mechanical ventilation (NIMV) is used with increasing frequency for the treatment of patients with respiratory failure caused by cystic fibrosis, yet the optimal mode of ventilation in such children is unknown. We compared the physiologic short-term effects of two ventilators with different modes (one pressure support and the other assist control/volume-targeted [AC/VT]) commonly used for domiciliary ventilation.

DESIGN

Prospective, randomized, crossover comparison of two ventilators with different modes.

SETTING

Tertiary pediatric university hospital.

PATIENTS

Eight children with cystic fibrosis (age, 11-17 yrs) and chronic respiratory failure (pH 7.4 +/- 0.0; PaO2, 57.5 +/- 7.5 torr; PaCO2, 46.1 +/- 2.5 torr), naive to NIMV.

INTERVENTIONS

Two 20-min runs of pressure support and AC/VT ventilation were performed in random order, each run being preceded and followed by 20 mins of spontaneous breathing.

MEASUREMENTS

Flow and airway pressure and esophageal and gastric pressures were measured to calculate esophageal (PTPes) and diaphragmatic pressure-time product (PTPdi) and the work of breathing.

RESULTS

The two NIMV sessions significantly improved blood gas variables and increased tidal volume with no change in respiratory rate. Indexes of respiratory effort decreased significantly during the two modes of NIMV compared with spontaneous breathing, with PTPdi/min decreasing from 497.8 +/- 115.4 cm H2O x sec x min(-1) during spontaneous breathing to 127.8 +/- 98.3 cm H2O x sec x min(-1) and 184.3 +/- 79.8 cm H2O x sec x min(-1), during AC/VT and pressure support, respectively (p <.0001), and the work of breathing decreasing from 1.83 +/- 0.12 J.L-1 during spontaneous breathing to 0.48 +/- 0.32 J.L-1 and 0.75 +/- 0.30 J.L-1, during AC/VT and pressure support, respectively (p <.0001). In addition, the effect of AC/VT ventilation was significantly superior to pressure support judged by PTPes and the work of breathing, but this result was explained by three patients who adapted extremely well to the AC/VT ventilation, with the disappearance of ventilator triggering, in effect adopting a controlled mode. There was a correlation between the improvement in PTPdi/min or the work of breathing and patient's subjective impression of comfort during the AC/VT ventilation.

CONCLUSIONS

In awake, stable children with cystic fibrosis, both AC/VT and pressure support unloaded the respiratory muscles. The disappearance of ventilator triggering occurred in a subgroup of patients during AC/VT ventilation, and this explained the good tolerance and the superiority of this mode in the present study.

[Value of high frequency (20mhZ) and doppler ultrasound in the diagnosis of pigmented cutaneous tumors]

PURPOSE

Diagnosis of pigmented skin tumors is often difficult. The aim of the present study is to evaluate high frequency ultrasound and Doppler ultrasound in the localization and the characterization of these tumors.

MATERIAL AND METHODS

One hundred and seventy six pigmented skin tumors including melanocytic and non melanocytic, benign and malignant lesions have been examined before resection using high frequency ultrasound (20MHz probe) and Doppler ultrasound (13MHz probe-Doppler frequency: 7MHz). Imaging data have been correlated with histological data, available in all cases.

RESULTS

Tumors seen at ultrasound were hypoechoic lesions, some of which, particularly malignant melanocytic tumors were vascularized. Precise ultrasonographic location of the tumor was correlated to its histological location: epidermis for purely epidermal proliferations (seborrheic keratoses), superficial dermis for dermal proliferations originating from epidermis (benign dermal nevi, melanomas during vertical growth phase, basal cell carcinomas), middle and deep dermis for dermal proliferations originating from dermis (fibrous histiocytomas, angiomas).

CONCLUSION

Ultrasound may help in assessing positive and differential diagnosis of pigmented skin tumors as it precises, before histological examination, the exact location of the lesion within the different skin layers and its origin. As far as malignant melanocytic tumors are concerned, high frequency ultrasound and Doppler ultrasound appear promising in diagnosis algorithm and pronosic of these lesions.

Optimization of aerosol deposition by pressure support in children with cystic fibrosis: an experimental and clinical study

Nebulized aerosols are commonly used to deliver drugs into the lungs of patients with cystic fibrosis (CF). The aim of this study was to assess the effectiveness of pressure-support (PS) ventilation in increasing aerosol deposition within the lungs of children with CF. An in vitro study demonstrated the feasibility of coupling a breath-actuated nebulizer to a PS device. An in vivo study was done with 18 children (ages 6 to 21 yr) with clinically stable CF, each of whom underwent both a standard and a PS-driven ventilation scan (control session and PS session, respectively). In addition, a perfusion scan was used to determine lung outlines and to construct a geometric model for quantifying aerosol deposition by radioactivity counting in MBq. Homogeneity of nebulization was evaluated from the four first-order moments of aerosol distribution in the peripheral and central lung regions. The time-activity nebulization curve was linear in all patients, with higher slopes during the PS than during the control session (0.43 +/- 0.07 [mean +/- SD] MBq/min and 0.32 +/- 0.23 MBq/min, respectively; p < 0.018). Quantitatively, aerosol deposition was about 30% greater after the PS session (4.4 +/- 2.7 MBq) than after the control session (3.4 +/- 2.1 MBq; p < 0.05). Similarly, deposition efficacy (as a percentage of nebulizer output) was significantly better during the PS session than during the control session (15.3 +/- 8.3% versus 11.5 +/- 5.7%, p < 0.05). No differences in the regional deposition pattern or in homogeneity of uptake were observed. In conclusion, our data show that driving the delivery of a nebulized aerosol by noninvasive PS ventilation enhances total lung aerosol deposition without increasing particle impaction in the proximal airways.

[Peripheral stem cell collection, search for predictive factors: a multicenter study. Working Group on Transfusion and Therapeutic Techniques of the French Blood Transfusion Society ]

AIMS

A multicentric study involving 12 centers was made to investigate the results of peripheral stem cell collection carried out between 1996 and 1997 from 655 patients with hemopathic syndromes or malignant tumors, The aim of this investigation was to determine the predictive factors for transplant quality, and to thereby optimize collection procedures.

PATIENTS AND METHODS

Information sheets were completed for 1,346 cytapheretic sessions, i.e., 655 grafts. The samples were taken after induction chemotherapy and exposure to hematopoeitic colony-stimulating growth factors (except the LMCs). Each graft was defined as being of good or bad quality depending on the number of CD34+ cells that it contained. Based on the data available in the literature, a workgroup consensus was reached that a level of CD34+ cells +/- 2.10(6)/kg recipient body weight constituted a good transplant criterion. The 2 subgroups (good graft versus lower quality graft) were compared by univariate analysis followed by discriminant multivariate analysis.

RESULTS

It was established that a number of parameters were significantly linked to the criterion of collection quality; however, 3 predictive factors emerged from the multivariate analysis--the level of circulating CD34+ cells; the number of cytaphereses; the number of blood volumes treated.

CONCLUSION

It was concluded that the level of circulating CD34+ cells seems to be an essential aspect in predicting the quality of the transplant and the number of cytaphereses required to obtain a sufficiently rich collection. Moreover, it also appears that at least 2 blood volumes should be treated to optimize the results.

[Diagnosis of malnutrition in the elderly by dual energy absorptiometry]

OBJECTIVES

Denutrition is a frequent condition in elderly persons and may have major consequences. A noninvasive investigation, whole body dual energy X-ray absorptiometry, should allow, by direct measurement of body composition, early and reliable diagnosis of denutrition. This study was conducted to elaborate a diagnostic tool using this exam and to test its validity.

PATIENTS AND METHODS

A global index of denutrition was proposed combining anthropometric, biological criteria, and the Mini Nutritional Assessment scale. Two agreement analyses were made between classical diagnostic criteria of nutritional status and body fat and fat free mass assessed by anthropometry and absorptiometry. An association between nutritional status and body absorptiometric composition were studied with univariate analysis followed by a multivariate logistic regression model. This model allowed an elaboration of a nutritional absorptiometric index (NAI).

RESULTS

One hundred one elderly subjects were included. Twenty-three were considered to be in a state of denutrition. Agreement was poor between anthropometric and biological diagnostic criteria of denutrition. It was good between the different masses assess by anthropometry and absorptiometry. Subjects in a state of denutrition had significantly lower body fat and lower fat free mass. The fat free mass index (fat free mass divided by the square height) and body fat were entered into a logistic model and composed the NAI, which showed good diagnostic validity in terms of specificity and sensitivity.

DISCUSSION

Absorptiometry appears to be a simple reliable diagnostic tool for assessing denutrition in elderly persons in routine practice. Further studies are required and should lead to a confirmation of the interest of these absorptiometric indexes.

[Comparison of behavior characteristics of the spontaneously alert state and the liberated state in the term newborn]

Occupational therapists evaluate the capacities of infants at younger ages than ever before. The variability of the infants' state has an inevitable influence on the expression of their behaviours. In order to counter the effect of this instability, Grenier (1985) suggests inducing the "liberated state," which optimizes the infant's level of attention. The aim of this study was to identify the behaviours that discriminate this liberated state from the alert state (state 4) as described by Brazelton (1973). Some of the parameters that were defined in the Synactive Theory of Development Model (Als, 1982) were used in order to document the behaviours of the infants observed in the two different states. The average age of the infants, at the time of observation, was 62 hours. The duration of the observation was 5 minutes. Among the 54 newborns that were evaluated, 21 were observed in the two states under study; 33 were evaluated in one state only. The results confirm a greater stability of the "liberated state". Stress and self-regulation behaviours, and the need for external regulation are less frequent in this state; these differences are statistically significant (p < 0.05). Goal-directed movements are more frequent in the "liberated state" (p < 0.001). The authors suggest the use of the "liberated state" to further document the early capacities of infants.

Loss-of-function mutations in a human gene related to Chlamydomonas reinhardtii dynein IC78 result in primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a group of heterogeneous disorders of unknown origin, usually inherited as an autosomal recessive trait. Its phenotype is characterized by axonemal abnormalities of respiratory cilia and sperm tails leading to bronchiectasis and sinusitis, which are sometimes associated with situs inversus (Kartagener syndrome) and male sterility. The main ciliary defect in PCD is an absence of dynein arms. We have isolated the first gene involved in PCD, using a candidate-gene approach developed on the basis of documented abnormalities of immotile strains of Chlamydomonas reinhardtii, which carry axonemal ultrastructural defects reminiscent of PCD. Taking advantage of the evolutionary conservation of genes encoding axonemal proteins, we have isolated a human sequence (DNAI1) related to IC78, a C. reinhardtii gene encoding a dynein intermediate chain in which mutations are associated with the absence of outer dynein arms. DNAI1 is highly expressed in trachea and testis and is composed of 20 exons located at 9p13-p21. Two loss-of-function mutations of DNAI1 have been identified in a patient with PCD characterized by immotile respiratory cilia lacking outer dynein arms. In addition, we excluded linkage between this gene and similar PCD phenotypes in five other affected families, providing a clear demonstration of locus heterogeneity. These data reveal the critical role of DNAI1 in the development of human axonemal structures and open up new means for identification of additional genes involved in related developmental defects.

[Computed tomography imaging of abdominal wall metastases after laparoscopy]

We report a case of abdominal wall metastases which occurred after diagnostic laparoscopy in a 64-year-old man presenting with gallbladder carcinoma and peritoneal carcinomatosis. CT showed enhancing masses along the laparoscopic tracts, suggesting metastatic seeding at the time of the surgery. This unusual complication fuels the current debate regarding indications of laparoscopic surgery in patients with malignancy.

[Clinical and respiratory function follow-up of 39 infants treated with neonatal respiratory extracorporeal assistance]

The aim of this prospective study was to evaluate the consequences of neonatal treatment with a venovenous extracorporeal respiratory assistance.

POPULATION AND METHODS

Thirty nine neonates (28 boys) with acute respiratory failure were included. Extracorporeal respiratory assistance consisted of an apnoeic oxygenation with low frequency positive pressure ventilation and extracorporeal membrane CO2 removal through a venous single canula perfusion circuit. The causes of respiratory distress were: 15 meconium aspiration syndrome, 12 respiratory distress syndrome, six hyaline membrane disease, three sepsis, two diaphragmatic hernia, and one post-surgery Mendelson syndrome. The mean duration of mechanical ventilation was 18 days, including 5 days of extracorporeal respiratory assistance. The prospective follow-up included physical examination, chest radiographs, scintigraphy and pulmonary function tests. These tests studied the following parameters: functional residual capacity by helium dilution technique, lung resistance and dynamic lung compliance by the esophageal balloon technique and blood gases with arterialized blood samples.

RESULTS

The mean duration of the follow-up was 21.3 months (6 months to 5 years). Results showed in the first year 33% of children with chronic obstructive pulmonary disease and chest (X-ray abnormalities, such as bronchopulmonary dysplasia in 23% of children. Data of pulmonary function test at the end of the first year: lung resistance and functional residual capacity were within limits of predicted values for height, and dynamic lung compliance was slightly decreased; according to the analysis of the functional profile: 31% without abnormality, 41% of obstructive syndrome and 26% with restrictive pattern. Blood gases were normal in 37 children. At the end of the second year, we noticed normal functional residual capacity, an increase of lung resistance while lung compliance was normalized; functional profile was quite different: with a decrease of the number of patients without abnormality (22%) and increase of those with obstructive syndrome (56%).

CONCLUSION

The percentage of abnormalities is high but these are moderate in most cases, especially if we compare with the initial seriousness of the pulmonary pathology. We suggest a regular follow-up to study the respective incidence of pulmonary disease and/or extracorporeal respiratory assistance over these abnormalities.

Chest physiotherapy in cystic fibrosis: improved tolerance with nasal pressure support ventilation

OBJECTIVE

Chest physiotherapy (CPT) is an integral part of the treatment of patients with cystic fibrosis (CF). CPT imposes additional respiratory work that may carry a risk of respiratory muscle fatigue. Inspiratory pressure support ventilation (PSV) is a new mode of ventilatory assistance designed to maintain a constant preset positive airway pressure during spontaneous inspiration with the goal of decreasing the patient's inspiratory work. The aim of our study was 1) to evaluate respiratory muscle fatigue and oxygen desaturation during CPT and 2) to determine whether noninvasive PSV can relieve these potential adverse effects of CPT.

METHODS

Sixteen CF patients in stable condition with a mean age of 13 +/- 4 years participated to the study. For CPT, we used the forced expiratory technique (FET), which consisted of one or more slow active expirations starting near the total lung capacity (TLC) and ending near the residual volume. After each expiration, the child was asked to perform a slow, nonmaximal, diaphragmatic inspiration. After one to four forced breathing cycles, the child was asked to cough and to expectorate. A typical 20-minute CPT session consisted of 10 to 15 FET maneuvers separated by rest periods of 10 to 20 breathing cycles each. During the study, each patient received two CPT sessions in random order on two different days, at the same time of day, with the same physiotherapist. During one of these two sessions, PSV was provided throughout the session (PSV session) via a nasal mask using the pressure support generator ARM25 designed for acute patients (TAEMA, Antony, France). The control session was performed with no nasal mask or PSV. Both CPT sessions were performed without supplemental oxygen. Lung function and maximal inspiratory pressures (PImax) and expiratory pressures (PEmax) were recorded before and after each CPT session.

RESULTS

Mean lung function parameters were comparable before the PSV and the control sessions. Baseline pulse oximetry (SpO2) was significantly correlated with the baseline vital capacity (% predicted) and forced expiratory volume in 1 second (FEV1) (% predicted). PSV was associated with an increase in tidal volume (Vt) from 0.42 +/- 0.01 liters to 1.0 +/- 0.02 liters. Respiratory rate was significantly lower during PSV. SpO2 between the FET maneuvers was significantly higher during PSV as compared with the control session. SpO2 decreases after FET were significantly larger during the control session (nadir: 91.8 +/- 0. 7%) than during the PSV session (93.8 +/- 0.6%). Maximal pressures decreased during the control session (from 71.9 +/- 6.1 to 60.9 +/- 5.3 cmH2O, and from 85.3 +/- 7.9 to 77.5 +/- 4.8 cmH2O, for PImax and PEmax, respectively) and increased during the PSV session (from 71.6 +/- 8.6 to 83.9 +/- 8.7 cmH2O, and from 80.4 +/- 7.8 to 88.0 +/- 7.4 cmH2O, for PImax and PEmax, respectively). The decrease in PEmax was significantly correlated with the severity of bronchial obstruction as evaluated based on baseline FEV1 (% predicted). Forced expiratory flows did not change after either CPT session. The amount of sputum expectorated was similar for the two CPT sessions (5.3 +/- 5.3 g vs 4.6 +/- 4.8 g after the control and PSV session, respectively; NS). Fifteen patients felt less tired after the PSV session. Ten patients reported that expectoration was easier with PSV, whereas 4 did not note any difference; 2 patients did not expectorate. Nine patients expressed a marked and 5 a small preference for PSV, and 2 patients had no preference. The physiotherapists found it easier to perform CPT with PSV in 14 patients and did not perceive any difference in 2 patients.

DISCUSSION

Our study in CF children shows that respiratory muscle performance, as evaluated based on various parameters, decreased after CPT and that significant falls in oxygen saturation occurred after the FET maneuvers despite the quiet breathing periods between each FET cycle. These unwanted effects of CPT were

[Pathophysiology of acute thoracic syndrome]

Pulmonary complications are the leading cause of morbidity and mortality in sickle cell disease patients. Acute chest syndrome (ACS), in which chest pain and dyspnea, occurs in combination with a recent chest radiograph abnormality, raises both diagnostic and therapeutic challenges. The pathogenesis of ACS involves alterations in blood rheology, increased coagulability, and, above all, increased adhesion of sickle cells to the vascular endothelium and nitric oxide-mediated dysregulation of vascular reactivity. Sickle cell disease thus impacts all the cells in the vascular environment. Recently gained insights into pathophysiology offer hope that new treatments for preventing and treating acute and chronic pulmonary complications will soon become available.

Selection and characterization of two specific monoclonal antibodies directed against the two variants of human herpesvirus-6

Monoclonal antibodies (mAbs) specific for human herpesvirus-6 (HHV6) proteins were derived from the splenocytes of mice immunized with HHV6 TAN isolate-infected peripheral blood mononuclear cells. The two mAbs 8C8 and 7C7 reacted by means of immunofluorescence and immunoperoxidase assays with both variant A and variant B isolates giving two different staining patterns. In infected cells, cytoplasmic diffuse staining was observed with mAb 8C8, whereas intense nuclear staining was obtained with mAb 7C7. These different locations of viral target proteins were confirmed by confocal microscopy. The mAb 8C8 reacted with a family of six glycoproteins designated as the gp72 complex in the case of variant A strains and gp63 complex in the case of variant B strains. The endoglycosidases H and F reduced those glycoproteins to a putative precursor molecule of 58 kDa. The mAb 7C7 reacted with 116 and 109 kDa proteins with the two HHV6 variants. These two mAbs did not neutralize virion infectivity in the absence of complement. No cross-reactivity was observed when these mAbs were used in immunoperoxidase assay and immunoblotting against the proteins of human cytomegalovirus or other human herpesviruses. Thus, the two mAbs 8C8 and 7C7 may be valuable tools for the diagnosis and biological investigation of HHV6 infections.

[Mucoviscidosis: therapeutic strategies are multiplying]

Since the cloning of the defective gene in cystic fibrosis, much has been learned on the function of CFTR and on the mechanisms regulating its expression. Based on the current understanding of the processes involved in lung disease progression, a number of approaches have been developed using gene therapy and pharmacological agents. Several of these agents have been reported to restitute a function to CFTR with specific mutations. Other molecules act on channels other than CFTR, and may be effective by bypassing CFTR itself. In the present review the various therapeutical strategies currently investigated are discussed.

[Imaging of adrenal incidentalomas]

Imaging plays an important role in evaluating fortuitously discovered adrenal masses. These unanticipated masses (incidentalomas) are usually discovered at CT examinations. Although most incidentally discovered adrenal tumors are non-hyperfunctioning adenomas, they must be distinguished from primary or secondary malignant lesions. Recent studies have established that both unenhanced CT scans and chemical shift MR imaging can accurately differentiate benign adenomas from nonadenomatous masses by features that reflect the large amount of lipid found in most adenomas and absent in most nonadenomas. We review here the current imaging issues concerning adrenal incidentalomas including diagnostic approaches and management.

[Value of high-frequency (20 MHz)in the diagnosis of cutaneous tumors]

The purpose of the present study is to asses the value of high frequency ultrasonography (20 MHz), a new noninvasive imaging technique, in cutaneous tumors. Cutaneous tumors are clinically varied and their diagnosis is still based on histopathological analysis. 140 cutaneous tumors have been examined with US and imaging findings have been compared to the results of clinical and histological examinations. This study shows that high frequency ultrasonography, even though it cannot replace pathological analysis, may help the dermatologist in the positive diagnosis of some cutaneous tumors and in accessing the location and the in depth-extension of the lesions in the different layers of the skin.

Mycobacterial lung disease in cystic fibrosis: a prospective study

BACKGROUND

Patients with cystic fibrosis (CF) may be predisposed to airway infections with unusual organisms, such as mycobacteria. The aim of the study was to determine the incidence and clinical picture of mycobacterial infection in CF children.

METHODS

At least 2 acid-fast bacillus (AFB) smears and mycobacterial cultures were performed on a prospective basis on 682 sputum specimens from 106 patients during a 1-year period.

RESULTS

Thirty-three percent of the cultures were contaminated with other bacteria. Seven children had at least one sputum culture positive for one mycobacterium. Five children had only one positive AFB culture. Their clinical status and lung function remained stable during follow-up. Two teenagers with severe lung disease had several positive AFB smears and cultures for Mycobacterium chelonae and Mycobacterium abscessus. The isolation of M. chelonae and M. abscessus was associated with a clinical and functional decline. Clarithromycin treatment resulted in temporary improvement with the disappearance of the mycobacteria after 6 months of treatment. This prospective study shows an incidence of 2.3% for positive cultures. The prevalence was 6.6% for mycobacterial colonization but only 1.9% for mycobacterial lung disease in our pediatric population.

CONCLUSIONS

We recommend performing AFB smears and cultures in CF children with severe lung disease and/or during a lung exacerbation. In these patients persistence of M. chelonae or M. abscessus in sputum should lead to consideration of treatment with clarithromycin.

[Bronchopulmonary dysplasia]

Bronchopulmonary dysplasia (BPD), a respiratory disorder first described in prematurely born infants with respiratory distress syndrome (RDS) treated with mechanical ventilation and oxygen supplementation, is the most common cause of chronic lung disease in infants. It is defined as the need for increased inspired oxygen at 28 days of age, and is observed with the highest frequency following premature delivery of very low birth weight infants. Indeed, an incidence of 48% has been recently reported in a population with a mean gestational age of 27 weeks. The etiology of BPD is multifactorial including lung immaturity, respiratory distress, oxygen therapy, and mechanical ventilation. Based on the current understanding of the pathogenesis of the disease, several therapeutical strategies are used. One of them is focused on the prevention of BPD by correcting surfactant deficiency in premature infants with RDS using exogenous surfactant, and also by improving the techniques of mechanical ventilation used for the management of RDS. Another approach which is being developed is focused on the factors involved in the processes of repair of the injured immature lung. These factors include the use of inhibitors of the inflammatory cascade, antioxidants, and inhibitors of fibrosis.

[Pulmonary toxicity of drugs and thoracic irradiation in children]

The pathology of drug-induced pulmonary toxicity in children is poorly understood and probably under-estimated, in the absence of any prospective studies evaluating in a systematic fashion the side effect of medication on the respiratory apparatus. The pulmonary toxicity of thoracic irradiation has markedly receded with more restricted indications for this sort of treatment. Three clinical patterns are most commonly encountered in drug induced lung disease in children: interstitial lung disease, hypersensitivity lung disease and non-cardiogenic pulmonary oedema. The diagnosis is a diagnosis of exclusion and rests on a group of clinical arguments and also on the progress of the disease. Broncho-alveolar lavage rules out infectious disease. Respiratory function tests show non-specific anomalies. A lung biopsy may be indicated. The mechanism of the pulmonary toxicity are associated with disequilibrium of the oxidant/antioxidant and protease/antiprotease system as well as disturbance of the immune response or alteration of the pulmonary matrix by disease of the collagen system. Increased toxicity may be seen in children because of a very significant cumulative dose. The cytotoxic drugs which are most often implicated in causing this are bleomycin, methotrexate, cyclophosphamide and busulfan. Other drugs which are responsible for toxic lung disease are nitrofurantoin, sulfasalazine, D-penicillamine, betalactams, Diphenyl-hydantoin and carbamazepine. Acute post-radiation lung disease is rare. Post-radiation fibrosis is found six months after irradiation and hinders thoraco-pulmonary growth in the child. It is important to assess lung function in all children before any chemotherapy or thoracic irradiation. Cytotoxic drugs are the most common cause of toxic lung disease. This iatrogenic disease requires a multi-discipline approach to ensure the quality of care for these children.