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Biomedical subjects

C K van der Ent

Publications and source records attributed to C K van der Ent.

At least 19 recordsLinked to original sources
PubMed2004

The Wheezing Illnesses Study Leidsche Rijn (WHISTLER): rationale and design.

The Wheezing Illnesses Study Leidsche Rijn (WHISTLER) was initiated in December 2001 as a single-centre prospective birth cohort study and will include a population-based sample of at least 2000 healthy newborns. The aims of WHISTLER are to investigate determinants for wheezing illnesses (including neonatal lung function, viral infections, asthma-susceptibility genes and endotoxin exposure) and to derive a comprehensive risk score, that is appropriate for use in primary health care and allows for efficient planning of early preventive strategies. Baseline examination includes a questionnaire evaluating known risk factors for wheezing illnesses; anthropometric measurements; measurements of infant and parental lung function; and sampling of infant and parental DNA. Participants will be followed for respiratory events using data from a daily respiratory symptom questionnaire; visits to the general practitioner (primary health care visits, drugs prescriptions and hospital referral); viral sampling during wheezing episodes; and house dust sampling. Based on actual neonatal care practice and embedded in a larger epidemiological study, the Utrecht Health Project, WHISTLER will provide an unique framework to address issues in childhood respiratory disease that are currently insufficiently understood. In particular, WHISTLER will provide a well-balanced view on the prognostic power of neonatal lung function and genetic and environmental factors (including viral infections and endotoxin exposure) to predict wheezing illnesses from birth to young adulthood and beyond. In the scope of prevention, WHISTLER is expected to support the design of solid based prevention measures to reduce respiratory morbidity, mortality and associated costs, and to improve quality of life.

Dust↗
PubMed2003

[Four infants with congenital cystic malformation of the lung: different routes of diagnosis and forms of management].

In four neonates, two boys and two girls, congenital cystic malformation of the lung was diagnosed. Two cases were diagnosed during prenatal ultrasound investigation. One of the patients recovered by a wait-and-see policy, one after antibiotic treatment and two following surgical removal of the diseased lung sections. Congenital pulmonary cysts are rare; congenital cystadenomatoid malformation (CCAM) is the most prevalent form. The most common presentation of CCAM is respiratory distress immediately following birth. Some children are asymptomatic at birth, but present with recurrent respiratory infections later in childhood. With the increasing use of antenatal ultrasound, an increasing number of cystic lung lesions are diagnosed antenatally. The prognosis of these mostly asymptomatic lesions is not clear and indications for prenatal and postnatal interventions must be determined by a multidisciplinary approach. Recently, malignant pulmonary tumours were found to be associated with CCAM. This finding necessitates long-term follow-up, even of asymptomatic CCAM lesions.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed2003

Modeling of the expiratory flow pattern of spontaneously breathing cats.

A mathematical model was developed describing the entire expiratory flow pattern during spontaneous, tidal breathing in the absence of expiratory muscle activity. It provides estimates for the time constants of the respiratory system (tau RS(model)) and of the decay of continuing inspiratory muscle activity in early expiration (tau mus(model)). In ten anesthetized, tracheostomized cats flow, tracheal pressure and diaphragmatic EMG were measured during normal expirations and expirations with four different added resistances. No significant differences were found between tau RS(model) (0.21-0.49 sec) obtained by fitting the model to the flow data and tau RS obtained from the straight part of the expiratory flow-volume curve. tau mus(model) (0.050-0.052 sec) was comparable to similar time constants obtained from the integrated diaphragmatic EMG or from end-inspiratory, tracheal occlusion pressure. Fitted peak flow and time to peak tidal expiratory flow were not significantly different from those measured. In conclusion, for spontaneously breathing, anesthetized cats our model provides a close fit of the expiratory flow and parameter estimates were comparable with independently measured values.

Animals↗
PubMed2003

Applicability of interrupter resistance measurements using the MicroRint in daily practice.

This study was performed to evaluate the applicability of a simple device (MicroRint) for measuring airway resistance, to derive normal values and to compare values with maximal expiratory flow volume (MEFV) parameters in asthmatic and healthy children. Repetitive R(int) measurements were performed in 125 healthy children and 107 asthmatic children (age range 0.8-16.8 years). In 42 asthmatic patients R(int) and MEFV values were compared and in 29 asthmatic children bronchodilation testing was performed. Successful R(int) measurements were possible in 91% of the children. The mean coefficient of variation of repeated measurements was 7.1 (+/-6.1)%. R(int) values of healthy children showed a significant curvilinear correlation with age (r=-0.80, P < 0.001) and height (r=-0.81, P < 0.001). In asthmatic and healthy children R(int) values were comparable. A significant inverse correlation was found between R(int) and MEFV values (for FEV1 and R(int) r=-0.80, P < 0.001). After bronchodilation there was a significant increase in FEV1 and decrease in R(int), but changes between the two parameters did not correlate. In conclusion, the interrupter technique is feasible and repeatable in children and has a significant correlation with other parameters of airway caliber. Baseline values do not discriminate healthy from asthmatic children.

Airway Resistance↗
PubMed2003

Spirometry in young children: should computer-animation programs be used during testing?

Currently, computer-animation programs are frequently used to instruct and stimulate young children in performing maximal expiratory flow/volume (MEFV) curves. The reproducibility and maximal performance of MEFV manoeuvres with and without the use of two computer-animation programs (the "candles" and the "balloon" programs) were evaluated. Eighty-eight children, aged 4-8 yrs, were randomly assigned to one of the two animation programs. All children performed two series of at least three technically acceptable curves, one series with the incentive and one without, in random order. With the use of computer-animation programs, a lower proportion of children were able to fulfil international criteria for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) reproducibility. The use of incentives improved reproducibility and performance of peak expiratory flow (PEF). Performance of FVC decreased significantly in 6-8-yr-old children using the animation programs. Training with a program for a short period of time before the formal lung-function test may be valuable. According to the results, however, the use of these programs during tests under the guidance of an experienced lung-function technician cannot be routinely recommended because of possible deteriorating effects on reproducibility and performance of forced expiratory manoeuvres.

Child↗
PubMed2002

Lung function abnormalities in children with type I diabetes.

Recent developments in intrabronchial administration of insulin raise lung function in patients with type I diabetes as important issue. Several studies in adults report abnormalities of lung function of these patients. The aim of this study was to investigate lung function in children with type I diabetes. Twenty-seven children with type I diabetes performed measurement of airway obstruction (forced flow-volume curves), lung volumes and airway resistance (bodyplethysmography) and of pulmonary carbon monoxide diffusion capacity Mean age (+/- SD) of the children was 12.8 +/- 5 years. Mean time between the detection of type I diabetes and the lung function tests was 5.5 years with a variation from I to 17 years. The total airway resistance (Raw) was significantly higher compared to the reference values (P < 0.001). The other lung function parameters were not significantly different from reference values (P > 0.05). In this relatively small study no relationship between lung function abnormalities and age, the duration of disease or level of HbA1c was observed. Our data show that increase of airway resistance do occur in children withtype I diabetes. Progressive abnormalities in lung function might interfere with the promising results of treatment with intrabronchial administration of insulin.

Adolescent↗
PubMed2002

Treatment of children with cystic fibrosis: central, local or both?

UNLABELLED: Owing to a lack of longitudinal studies, the effect of centralization of care on pulmonary function and survival remains unclear. Three different levels of involvement of centralized care in the treatment of paediatric cystic fibrosis patients were compared with regard to longitudinal pulmonary function and nutritional and microbiological status in a 3-y period, and the literature was reviewed on the possible advantages and disadvantages of centralized care. The study included 105 paediatric patients attending the Cystic Fibrosis Centre between January 1997 and January 2001. Twenty-three patients were treated by local paediatricians according to the protocol of the Centre and were seen only once a year at the Centre, for an annual check-up (local care). Forty-one patients were treated at the Centre only (centralized care). The remaining 41 patients were treated in close cooperation between the Centre and local hospitals, with patients visiting the doctors alternately (shared care). The mean annual changes in pulmonary function and body mass index from all patients, as well as a microbiological survey, were reviewed. No significant differences were found between the three groups for annual changes in FEV1, FVC and body mass index, nor did the review of microbial colonization show any significant differences between the groups. Because the groups in this study were relatively small, the results might have been influenced by lack of power. CONCLUSION: In this relatively small group, no differences in pulmonary function, nutritional status or microbiological colonization between the three levels of involvement of centralized care could be found. This could signify that local paediatricians have a special role in the care for patients with cystic fibrosis, in close cooperation with the specialists at the Centre.

Analysis of Variance↗
PubMed2002

Children with mild asthma: do they benefit from inhaled corticosteroids?

In children with mild asthma, who show hardly any abnormalities in pulmonary function, objective measurement of the effect of inhaled corticosteroids is difficult. The short term effect of fluticasone propionate (FP) in these children was evaluated, using both subjective and objective parameters. A total of 68 children (5-10 yrs old) were randomly assigned to either FP 250 microg or placebo twice daily as metered-dose inhaler via spacer during 12 weeks. Symptom scores, use of rescue medication, wheezing, parent global evaluation and pulmonary function tests including forced expiratory volume in one second (FEV1), peak expiratory flow (PEF) and bronchial responsiveness (provocation dose of methacholine causing a 20% fall in FEV1 (PD20)) were evaluated. FP-treated versus placebo-treated children showed significant changes in percentage symptom-free days, use of beta2-mimetics, morning and evening PEF, FEV1 % pred and wheezing. No significant improvements were found in parent global evaluation, absolute values of FEV1 nor PD20. These findings show that inhaled corticosteroids are effective in children with mild asthma. This effect can be assessed by both objective and subjective parameters. Early start of inhaled corticosteroids should be considered even when pulmonary function is normal.

Administration, Inhalation↗
PubMed2002

Measurements of interrupter resistance: reference values for children 3-13 yrs of age.

The interrupter technique is a convenient and sensitive technique for studying airway function in subjects who cannot actively participate in (forced) ventilatory function tests. Reference values for preschool children exist but are lacking for children >7 yrs. Reference values were obtained for expiratory interrupter resistance (R(int,e)) in 208 healthy Dutch Caucasian children 3-13 yrs of age. A curvilinear relationship between R(int,e) and height was observed, similar to published airways resistance data measured by plethysmography. No significant differences in cross-sectional trend or level of R(int,e) were observed according to sex. It was found that Z-scores could be used to express individual R(int,e) values and to describe intra- and interindividual differences based on the reference equation: 10logR(int,e)=0.645-0.00668x standing height (cm) kPa x L(-1) x s(-1) and residual SD (0.093 kPa x L(-1) x s(-1)). Expiratory interrupter resistance provides a tool for clinical and epidemiological assessment of airway function in a large age range.

Adolescent↗
PubMed2001

Forced expiratory manoeuvres in children: do they meet ATS and ERS criteria for spirometry?

The aim of this study was to evaluate the applicability of American Thoracic Society and European Respiratory Society criteria for spirometry in children. Maximal expiratory flow/volume (MEFV) measurements from 446 school-age children, experienced in performing MEFV manoeuvres, were studied and acceptability (start-of-test (backward extrapolated volume as a percentage of forced vital capacity (FVC) ([Vbc%FVC) or as an absolute value (Vbe), end-of-test (forced expiratory time (FET)) and reproducibility criteria (absolute and percentage difference between best and second-best FVC and forced expiratory volume in one second (FEV1) (deltaFVC, deltaFVC %, deltaFEV1 and deltaFEV1 %)) were applied to these manoeuvres. The Vbe%FVC criterion was met by 91.5%, the Vbe <0.15 L criterion by 94.8% and the Vbe <0.10 L by 60.1% of children. Vbe <0.15 L appeared to be a more useful parameter than Vbe%FVC. The FET criterion was met by only 15.3% of children. deltaFVC <0.2 L and deltaFEV1 <0.2 L were met by 97.1% and 98.4%, and deltaFVC <0.1 L and deltaFEV1 <0.1 L by 79.8% and 84.3% of the children, respectively. These criteria appeared to be less useful compared to percentage criteria (deltaFVC % and deltaFEV1 %). Even experienced children did not meet all international criteria for spirometry. However, most of their MEFV curves are useful for interpretation. Based on the performance of these children, a re-evaluation of criteria for maximal expiratory flow/volume measurements in children is proposed.

Adolescent↗
PubMed2000

Flow/volume measurements from childhood to adulthood.

Flow/volume curves are the most frequently used pulmonary function test during childhood. Even preschool children are sometimes able to perform the maximal effort breathing techniques required for this pulmonary function test. The most important conditions for reliable measurement of flow/volume curves at all ages are reported here. In particular, testing atmosphere and equipment, pulmonary function technician requirements, testing procedure, reliability criteria, report making and interpretation are discussed.

Adult↗
PubMed1999

[Immunology in medical practice. XVIII [correction of XVII]. Children with recurrent airway problems: asthma is not always the cause.

Three children, two boys aged 16 and 11 years and a girl aged 16 years, with symptoms resembling asthma had been treated for years with inhaled corticosteroids and beta 2-sympathicomimetics without satisfactory results. It was found that the antibody production after vaccination with 23-valent pneumococcal vaccine was impaired. The symptoms diminished during maintenance treatment with antibiotics in two children and with intravenous immunoglobulins in one. In patients with recurrent respiratory problems, but no specific history of asthma, immunological investigation is warranted, especially in patients whose 'asthma' is accompanied by respiratory infections. When treated for their immunodeficiency these patients show remarkable improvement and the need for steroids often disappears.

Adolescent↗
PubMed1999

Lung function abnormalities and respiratory muscle weakness in children with juvenile chronic arthritis.

In contrast to adult rheumatoid arthritis (RA) little is known about the prevalence, nature and cause of lung function abnormalities in children with juvenile chronic arthritis (JCA). The aim of this study was to determine whether children with polyarticular and systemic onset JCA have lung function abnormalities and if so, whether they are related to pulmonary disease, thoracic and/or muscular involvement. We determined lung function and disability in 31 children with polyarticular and systemic JCA. Respiratory muscle function, thorax expansion and spine mobility were determined in the same patients, as well as in 32 matched healthy children. Peak expiratory flow (PEF) and forced vital capacity (FVC) were significantly reduced in JCA patients, when compared to reference values. Thorax expansion and spine mobility were normal, compared to paired controls. Maximum inspiratory (PI,max) and expiratory (PE,max) pressures were significantly reduced in patients compared to paired control subjects. A positive correlation was found between PE,max and FVC and PEF, an inverse correlation between expiratory pressure and disability. In conclusion, children with polyarticular and systemic juvenile chronic arthritis show a pronounced impairment in respiratory muscle strength, severe enough to cause mild lung function abnormalities and an increase in disability-scores.

Adolescent↗