[Persistent tachypnea in infants: possibly due to interstitial pneumonitis]. / Aanhoudende tachypneu bij een zuigeling: mogelijk interstitiële pneumonitis.

In three male infants aged 3, 4.5 and 11 months with tachypnea and feeding problems, the initial supplementary examination revealed no possible cause. The tissue obtained by open lung biopsy showed interstitial pneumonia/pneumonitis. The two youngest patients were treated with hydrochloroquine and prednisone; the youngest died at the age of 18 months. Both the infant who was maintained on hydrochloroquine and the one who did not receive treatment showed a normal respiratory frequency and growth during the following years. Tachypnea is less easily recognised in infants than in older patients. It may be the only early symptom of interstitial pneumonitis. A normal chest X-ray cannot exclude an incipient interstitial pneumonitis as the cause of the tachypnea. A high-resolution CT-scan of the lung parenchyma is necessary in order to detect the disease at an early stage. Histological examination of an open lung biopsy specimen is essential for the specific diagnosis, therapy and prognosis.

Functional residual capacity and static compliance during the first year in preterm infants treated with surfactant.

Individual lung development during the first year of life was studied in surfactant treated preterm infants with respiratory distress syndrome (RDS) and healthy controls, as well as in a group who subsequently developed chronic lung disease of the newborn (CLDN). Lung development was assessed from functional residual capacity (FRC) and compliance of the respiratory system (Crs). Twenty-one infants with RDS after preterm birth received surfactant treatment. Six of them developed CLDN. Eighteen preterm infants without RDS served as a control group. Lung function measurements were performed at term age and 4, 8, and 12 months afterwards. FRC was obtained by means of the closed-system helium dilution technique whereas static Crs was obtained by means of the weighted spirometer technique. At term age, FRC was lower in the CLDN group compared with uncomplicated RDS and controls (p < 0.05). No significant differences between groups were found in the development of FRC during the first year of life (p = 0.4). No differences were found in Crs during the first year of life in surfactant treated infants who recovered from uncomplicated RDS and the control group. However, lower values were found in the CLDN group (p < 0.05). We conclude that surfactant treated infants without CLDN have similar lung development during the first year of life as control preterm infants.

Pulmonary function in infants with neonatal chronic lung disease with or without hyaline membrane disease at birth.

We studied whether neonatal chronic lung disease (NCLD), hyaline membrane disease (HMD) and differences in ventilatory support affected pulmonary function during the first year of life, in 65 infants born prematurely. The relationship between body weight and oxygen consumption (V'O2) was also analysed. The study comprised 14 infants without cardiorespiratory disease, 19 infants with HMD but without NCLD, 9 infants with NCLD without prior HMD, and 23 infants with NCLD following HMD. At 6 and 12 months corrected postnatal age, static respiratory system compliance (Crs) was measured by weighted spirometry and the functional residual capacity by closed circuit helium dilution (FRCHe) combined with assessment of ventilation distribution from the mixing index (MI). Ventilatory support during the first 5 days of therapy was quantified from peak inspiratory pressure (PIP), mean airway pressure (MAP) and fractional inspiratory concentration of oxygen (FI,O2). Infants with NCLD had a shorter duration of gestation and lower birth weight than those without NCLD (Wilcoxon, p=0.002 and p=0.001, respectively). Pulmonary function at 6 and 12 months corrected age was not different between NCLD infants with or without HMD at birth. Infants with NCLD had lower Crs and MI than those without NCLD (analysis of variance (ANOVA), p<0.011), but their FRCHe was not different. V'O2 adjusted for body weight was comparable in the four groups. PIP and FI,O2 were higher (Wilcoxon, p<0.01) in the NCLD infants than in those with HMD alone, but MAP was not different. Except for FI,O2, these indices were not different among the infants with NCLD. We conclude that birth weight is the major determinant of the development of neonatal chronic lung disease. At 6 and 12 months corrected age, the abnormal pulmonary function is not associated with prior hyaline membrane disease.

Pulmonary function during the first year of life following acute viral bronchiolitis.

It has been suggested that acute viral bronchiolitis in infants may result in functional changes that predispose toward chronic pulmonary disease later in life. We assessed pulmonary function (PF) during the acute phase of viral bronchiolitis in infants and up to 12 mo later from static respiratory system compliance (Crs), using weighted spirometry, the distribution of ventilation by the mixing index (MI), and the functional residual capacity (FRC) measured by closed-circuit helium dilution (FRCHe). The study was performed in 24 infants (13 males and 11 females; median [25 to 75% range] age: 11 [9.6 to 13.3] wk; weight: 4.8 [4.3 to 5.0] kg; crown-to-heel length: 57.7 [55.5 to 59.0] cm) at admission and at 2 wk. In 17 infants, measurements were repeated 3 mo and 12 mo later. Predicted values and individual 95% prediction intervals for Crs, MI, and FRCHe were derived from 69 healthy infants (33 boys and 36 girls; median age [25 to 75% range]: 4.7 [2.0 to 21.4] wk; weight: 3.6 [3.0 to 6.9] kg; crown-to-heel length: 51.5 [48 to 61] cm). Data at admission and after discharge were compared by analysis of variance (ANOVA) with those in the healthy controls matched for crown-to-heel length. At admission all three variables gave lower average results than predicted means. Values for each index had attained a normal level 2 wk after admission; normal levels were maintained at 3 and 12 mo. The prevalence of recurrent wheezing (five of the 17 infants) was comparable with that reported in population studies. These findings suggest that in this population acute viral bronchiolitis did not lead to permanent changes in PF.

Strength of the Breuer-Hering inflation reflex in term and preterm infants.

The effect of the presence of the respiratory distress syndrome (RDS) or related factors (static compliance of the respiratory system and transcutaneous blood gases) and gestational age on the strength of the Breuer-Hering inflation reflex (BHIR) was studied in three groups of infants. Twenty-six ventilated preterm infants with and without RDS were studied 6 h after birth (group 1). In 24 preterm infants, we followed the development of reflex strength during the first year of life (group 2). Twenty-one healthy nonintubated term infants were studied within the first week of life (group 3). The BHIR was initiated by end-inspiratory occlusions, and the strength was characterized by the ratio of expiratory time after and without preceding airway occlusion. The static compliance of the respiratory system in ventilated infants was assessed by the multiple-occlusion technique. In group 1, reflex strength declined with increasing gestational age; in the presence of RDS or low respiratory compliance, the decline was less. Transcutaneous blood gases did not affect reflex strength. At term age, reflex strength was similar in spontaneously breathing preterm (group 2) and term infants (group 3). The BHIR decreased in strength during the first year after preterm birth. We conclude that 1) the strength of the BHIR decreases with increasing gestational and postnatal ages and 2) RDS, due to changes in respiratory system mechanics, causes an increase in reflex strength.

Respiratory illness in families of preterm infants with chronic lung disease.

AIMS--To examine the relation, based on two types of questionnaires, between (1) chronic lung disease of the newborn (CLDN) and lower respiratory illness (LRI) in siblings, and between (2) CLDN and asthma, chronic obstruction pulmonary disease (COPD), or allergy in parents and grandparents. METHODS--Data from 209 children born before 32 weeks of gestation were randomly taken from the records of three neonatal units. Taking into account age and gender, the excess of LRI was calculated for each family compared with the average of all families. Subsequently whether CLDN was associated with an excess of LRI in the family was tested. RESULTS--Thirty one (14.8%) children were diagnosed as having CLDN. The family probability index for LRI did not differ between children with or without CLDN. The prevalence of COPD, asthma, and allergy in parents of children with CLDN was similar to that of children without CLDN. The prevalence of LRI was 18.1% in study children, 29.6% in children with CLDN, and 16.9% in children without CLDN (P < 0.01). These prevalences were higher compared with that of a group of term siblings (9.3%) (P = 0.05). CONCLUSIONS--These findings suggest that CLDN in preterm children is not related to a genetic or familial predisposition towards asthma, COPD, or allergy.

Biochemical lung maturity, static respiratory compliance, and pulmonary gas transfer in intubated preterm infants with and without respiratory distress syndrome.

We investigated the relationship between tests of biochemical lung maturity [lecithin/sphingomyelin ratio (L/S ratio)], static compliance of the respiratory system (Crs), and estimates of pulmonary gas transfer [venous admixture and arterial/alveolar (a/A) ratio] in a group of intubated preterm infants with and without respiratory distress syndrome (RDS). Thirty infants were studied once (n = 26) or twice (n = 4). The L/S ratio was obtained by means of high-performance thin-layer chromatography and determination of the phosphorus content. Crs was obtained by the multiple occlusion technique. Transcutaneous blood gases and the percentage of oxygen in the inspired gas were recorded and estimates of pulmonary gas transfer were calculated using algorithms. L/S ratio and Crs correlated well (r = 0.73), indicating a higher compliance in biochemically more mature lungs. Both the a/A ratio and venous admixture correlated significantly with the L/S ratio and Crs (P < 0.001). Crs, L/S ratio, and a/A ratio decreased with increasing severity of radiological RDS, and the percentage venous admixture increased (P < 0.001). Sequential measurements in four infants during the acute phase and after RDS resolved indicated that clinical improvement coincided with improvements in biochemical lung maturity, Crs, and estimates of pulmonary gas transfer.

Pulmonary function during the first year of life in healthy infants born prematurely.

Premature birth is associated with increased respiratory morbidity. We investigated cross-sectionally, in 69 healthy infants who had never had cardiorespiratory problems, whether premature birth is associated with diminished pulmonary function. The study comprised 26 healthy infants born prematurely (PT), median gestational age 32 (26-36) weeks, and 43 healthy controls born full-term (FT), median gestational age 40 (37-42) weeks. Static respiratory system compliance (Crs) was assessed by weighted spirometry, combined with the measurement of the functional residual capacity by closed circuit helium dilution (FRCHe) and with assessment of ventilation distribution from the mixing index (MI). Repeatability of these indices was also assessed. Premature and full-term infants had the same length-corrected FRCHe; their Crs was different, but the difference disappeared when gestational age was taken into account. Mixing index was unrelated to body size and was not different between full-term and premature infants. Crown-heel length and lung volume were not different for any postconceptional age. However, infants born prematurely were smaller and had smaller lung volume at any postnatal age compared to those born at term. Repeatability of the indices was fair. These findings suggest that gestational age < 37 weeks is associated with normal respiratory system mechanics for body size, and normal distribution of ventilation in healthy infants who never had cardiorespiratory problems.

Changes of respiratory system mechanics in ventilated lungs of preterm infants with two different schedules of surfactant treatment.

We investigated the time course of changes in the static respiratory system compliance and resistance in relationship to surfactant administration by means of single-breath and multiple-occlusion techniques. The study comprised 12 infants receiving a high-dose schedule (200 mg/kg, maximum 600 mg/kg) and 13 infants receiving a low-dose schedule (100 mg/kg, maximum 300 mg/kg) of porcine surfactant. Eight healthy preterm infants served as a comparison group. Respiratory mechanics were studied before and at 1.5, 8, and 72 h after surfactant administration. Results were related to changes in gas transfer, including an estimate of venous admixture. Static compliance improved after surfactant instillation, and changes were similar in the two treatment groups during the first eight h (0.8 In.(hour + 1) mL.kPa-1). The compliance values remained below the values of the healthy comparison group during the whole study period, but resistance remained at the same level. There was a considerable delay in changes of respiratory mechanics in relationship to the rapid fall of the venous admixture, from 27 to 19%, and the rapid increase of the transcutaneous oxygen pressure/fraction of inspired oxygen ratio from 13 to 27 kPa within the hour. There were no clues that short-term changes in compliance were masked by breathing at a higher and flatter portion of the pressure-volume curve. Both treatment schedules resulted in a similar improvement of compliance within 72 h and the two groups benefited similarly in terms of venous admixture.

Water-sealed spirometer for measurements in newborns and infants.

Details are given of two spirometers for use in neonates and infants < 12 mo old. The minimum volumes are 520 and 670 ml, respectively. The maximum volume changes that can be recorded are 250 and 450 ml, respectively. The minimal detectable volume changes are 0.4 and 0.6 ml, respectively. Rebreathing of dead space gas is prevented by a fan producing a flow of 6.2 and 10.2 l/min, respectively; 100% gas mixing after injecting a gas bolus in the two spirometers is achieved in 5.7 and 6.6 s, respectively. Resistance to airflow is 0.2 kPa.l-1.s (2 cmH2O.l-1.s) at 150 ml/s in both spirometers. The frequency response of both instruments is flat to 6 cycles/s. The instruments can be easily cleaned and are suitable for bedside measurements.

[The dyspneic infant. Interpretation of symptoms of lower airway disorders in the first year of life]. / De benauwde zuigeling. Interpretatie van symptomen van lagere luchtwegaandoeningen in de loop van het eerste levensjaar.

A number of age-related anatomical and physiological factors place the respiratory system of the neonate and young infant in a potentially vulnerable position during disease states. Maintenance of a lung volume necessary for effective gas exchange is compromised by the floppy chest wall, the relatively stiff lungs and the horizontal position of the body. Respiratory muscles are prone to fatigue in case of increased respiratory loads and fail to move the rib cage efficiently. Many signs of lower airway disease, observed during the physical examination of the young infant, can be related to these factors. Awareness of them helps in the interpretation of these symptoms in order to make the correct diagnosis and to initiate treatment.

Respiratory system compliance assessed by the multiple occlusion and weighted spirometer method in non-intubated healthy newborns.

In 28 healthy newborn infants (median age 3.5 days), we compared the weighted spirometer (WS) with the multiple occlusion (MO) method for measuring respiratory system compliance (Crs). The MO method was unsuccessful in 8 infants. On average the two methods gave comparable results for compliance (Crs,ws = 40.4 +/- 13.8 and Crs,MO = 45.2 +/- 10.4 mL.kPa-1) in the remaining 20 infants; however, within-individual differences were often considerable, so that the methods did not give interchangeable results. Individual pressure-volume curves almost always intercepted the volume axis below the functional residual capacity with the MO technique, compatible with dynamic elevation of end-expiratory lung volume (EEL) due to inspiratory muscle activity during expiration. A (small) negative volume intercept occurred in less than 50% of curves with the WS method; in these cases it probably reflects alinearity of the compliance curve, an alteration in laryngeal braking or in respiratory muscle control of EEL, or all of these. Both methods provide valuable means for the non-invasive determination of respiratory system compliance in newborn infants, the differences in Crs being small and of minimal physiological significance; however, for individual follow-up they should not be used interchangeably.

[A case of Munchausen syndrome by proxy]. / Een geval van het syndroom van Münchhausen bij proxy.

In this paper the case is described of a one-year-old girl who was diagnosed as to have the Münchhausen syndrome by proxy. There had been a single-sided, chronic parotitis, followed by a single-sided orbita-cellulitis. In the pathological-anatomical matter derived from the parotid a substance was found that does not belong to the human body (most likely to be alum), and which contained aluminium, silica, and iron. Based on pediatric, psychological, and child psychiatric diagnoses, the conclusion was that in all probability the matter was injected by the patient's grandmother, who acted as foster-mother. The grand-mother herself appeared to be a patient with the Münchhausen syndrome. After the girl was separated from her grand-parents, she soon recovered. Following after a total stay of 18 months in three different hospitals, the girl could be placed in a therapeutic foster home.