Effect of sleep stages on measurements of passive respiratory mechanics in infants with bronchiolitis.

The measurement of passive respiratory mechanics by the single-breath occlusion technique is one of the more frequently used tests of infant lung function. Measurements are routinely done under chloral hydrate sedation, and a possible influence of sleep stages on these measurements has not been evaluated so far. We combined the assessment of passive respiratory mechanics with sleep stage monitoring in 44 infants and toddlers with mild to moderately severe bronchiolitis. In 31 infants, only nonrapid eye movement (NREM) sleep was recorded. In 13 patients who showed both NREM and rapid eye movement (REM) sleep, compliance of the respiratory system was significantly lower during REM than NREM sleep (73.2 +/- 19.7 vs. 81.2 +/- 21.3 mL/kPa, P = 0.0007), while resistance remained essentially unchanged. This finding was explained by an unchanged airway opening pressure in combination with a significantly decreased extrapolated volume. As tidal volume did not change from NREM to REM, this indicates reduced dynamic elevation of lung volume during REM sleep and thus supports previous observations of decreased lung volume in this sleep stage. From a practical perspective, these findings argue for the monitoring of sleep stage during measurements of passive respiratory mechanics, thereby increasing the complexity of these measurements significantly.

Atopy, lung function and bronchial responsiveness in symptom-free paediatric asthma patients.

In adolescence, some paediatric asthma patients will become symptom-free and require no further treatment. There is little information on the atopic status, lung function and bronchial responsiveness of these patients. Symptom-free asthma patients (n=118) aged 7.7-19.2 yrs, were evaluated 1 year after termination of therapy. Bronchial asthma had previously been diagnosed on the basis of recurrent wheezing episodes. Atopic status was assessed by skin-prick testing. Baseline lung function was measured by spirometry, flow-volume curve and plethysmography. Bronchial responsiveness was assessed nonpharmacologically by cold dry air challenge. Eighty one patients had at least one positive skin test result, and the remaining 37 were defined as nonatopic. In atopic subjects, the prevalence of bronchial hyperresponsiveness was significantly higher than in nonatopic patients (41 out of 81 versus 7 out of 37; p=0.001). Atopic subjects showed a significantly lower maximal expiratory flow at 25% remaining vital capacity (p<0.05) and a higher residual volume (p<0.05) than nonatopic subjects. Nonatopic subjects were significantly younger than atopic patients (p<0.01). These symptom- and medication-free paediatric and adolescent asthma patients could, thus, be divided into two groups: 1) atopic subjects with a tendency towards bronchial hyperresponsiveness; and 2) nonatopic subjects with better lung function and normal bronchial responsiveness In view of the increased understanding of the epidemiology of early childhood wheezing, these findings support the concept of different pathogenic mechanisms underlying wheezing episodes in early childhood.

Extralobar sequestration with unusual arterial supply and venous drainage.

We present a case of extralobar pulmonary sequestration between the left lower lobe and diaphragm with an unusual arterial blood supply and venous drainage. Angiography revealed a large systemic artery arising from the left subclavian artery. The venous return paralleled this anomalous artery and drained into the left subclavian vein. This case illustrates the wide anatomic variability of such complex bronchovascular anomalies. Careful preoperative evaluation of both the arterial supply and venous drainage is important to avoid intraoperative complications. Angiography provides clear definition of these abnormal vascular structures, which is essential for appropriate therapeutic management.

Comparing methods for assessing bronchial responsiveness in children: single step cold air challenge, multiple step cold air challenge, and histamine provocation.

Cold air challenge (CACh) can be applied by either a single step (SSCACh) or a multiple step (MSCACh) protocol. The interrelationship of the responses of the different protocols has not yet been studied. Furthermore, there is contradictory information on the correlation of cold air challenge responses to the outcome of pharmacological provocations. A single and a multiple step cold air challenge and a histamine provocation were performed in random order on three consecutive days on 28 children and adolescents with bronchial asthma, who were currently symptom- and medication-free. Single step cold air challenge consisted of a 4 min isocapnic hyperventilation of dry, -10 degrees C air; the subjects's response was quantified by the induced change in forced expiratory volume in one second (FEV1). Multiple step cold air challenge consisted of a series of 3 min, cold dry air hyperventilation steps from 20 to 80% of maximal voluntary ventilation (MVV); response was expressed as the provocative dose causing a 10% fall in FEV1 (PD10). Histamine provocation consisted of a series of 2 min inhalations of stepwise increasing histamine concentrations from 0.03 to 8.0 mg.mL-1; response was expressed as the provocative concentration of histamine causing a 20% fall in FEV1 (PC20). Change in FEV1 (delta FEV1) (SSCACh) correlated closely with PD10 (MSCACh); scatter around the regression line was minimal. With one exception, both types of CACh identified the same subjects as hyper- and normoresponsive. delta FEV1 (SSCACh) correlated significantly to PC20 (histamine), but scatter around the regression line was substantial. The correlation of PD10 (MSCACh) to PC20 (histamine) failed to reach statistical significance. These results indicate that the stimulus applied and the bronchoconstrictor mechanism activated, and not the challenge protocol, determine the outcome of a cold air challenge. In clinical practice, a brief single step cold air challenge can substitute for a more time-consuming multiple step cold air challenge. As nonpharmacological challenges seem to measure a different type of bronchial responsiveness, neither a single step nor a multiple step cold air challenge can substitute for a pharmacological provocation.

A comparison of a single-step cold-dry air challenge and a routine histamine provocation for the assessment of bronchial responsiveness in children and adolescents.

BACKGROUND: It has remained unclear whether bronchial responsiveness as measured by a single-step cold-dry air challenge (CACh) correlates closely to the responsiveness that is assessed by a routine pharmacologic challenge. METHODS: On 2 consecutive days, we performed a CACh and a histamine challenge in 128 symptom- and medication-free pediatric and adolescent asthma patients. The CACh consisted of 4 min of isocapnic hyperventilation of -10 degrees C, absolutely dry air; responsiveness was expressed by the induced change in FEV1 (delta FEV1). The histamine challenge consisted of sequential inhalations of incremental increases in concentrations of histamine; responsiveness was expressed by the concentration which caused a 20% fall of FEV1 (PC20). RESULTS: Five children did not bronchoconstrict sufficiently in the histamine challenge for measuring a PC20 and were excluded from analysis. In the remaining 123, delta FEV1 (CACh) ranged from +5 to -73%, PC20 (histamine) from 0.05 to 7.2 mg/mL. There was a statistically significant correlation between delta FEV1 and PC20 (r = 0.54, p < 0.001), but also a considerable scatter of individual data points around the regression line. Fifty-two subjects were hyperresponsive by CACh and 114 by histamine criteria. CONCLUSIONS: There is a relatively weak correlation between the results of these two challenges; thus, one cannot be substituted one for the other. Histamine appears as more sensitive in detecting airway hyperresponsiveness than CACh. The poor correlation between the responses to these two challenges can be explained by differences between the challenge protocols, or, alternatively, by differences between applied stimuli and activated mechanisms.

Lung volume measurements in wheezy infants: comparison of plethysmography and gas dilution.

The accuracy both of plethysmographic measurements of thoracic gas volume (TGV) and determinations of functional residual capacity (FRC) by gas dilution techniques in infants with obstructive lung disease is subject to continued dispute. We studied 25 wheezy infants and compared TGV derived from end-expiratory airway occlusions (TGVEE), corrected TGV after end-inspiratory airway occlusions (TGVEI), and FRC determined by nitrogen wash-out (FRCN2). Group mean TGVEE and TGVEI differed significantly (25.8 +/- 8.4 versus 24.6 +/- 7.1 ml.kg-1). TGVEE and FRCN2 did not differ significantly. TGVEE and TGVEI, as well as TGVEE and FRCN2, and TGVEI and FRCN2 data, respectively, showed lack of agreement. Based on 95% confidence intervals, calculated from TGVEE data, 14 of the 25 infants showed a significantly higher TGVEI than TGVEE; only one patient had a significantly lower TGVEI. Compared to FRCN1 data, TGVEE and TGVEI measurements yielded lower values in at least one third of our patients. The present study illustrates, that there is no gold standard for the measurement of lung volume in infants with airway obstruction.

[Measuring lung volume in the infant--problems with the nitrogen washout method]. / Die Messung des Lungenvolumens beim Säugling--Probleme mit der Stickstoffauswaschmethode.

The open-circuit nitrogen washout technique, as developed by Gerhardt et al., seems to be ideally suited for assessing functional residual capacity (FRC) in infants. By performing this measurement in over 250 infants throughout the last three years, we gathered considerable practical experience of our own, but also encountered several methodological problems, which, so far, have received only little attention by the relevant literature, or have remained unresolved altogether. Our data illustrate the importance of reproducing the infant's own breathing rate and tidal volume when calibrating the system. The choice of the O2-background-flow should be based on the individual peak tidal inspiratory flow, as derived from the tidal flow-volume loop. The importance of maintaining this O2-background-flow unchanged between calibration and measurement is also demonstrated. The question, at which N2-concentration the measurement should be terminated, has remained unresolved. Diffusion of N2 from blood and tissue into the alveolar space is responsible for considerable noise. Our own measurements resulted in widely differing FRC-values for different N2-target-concentrations; these differences seem to increase with more severe bronchial obstruction. Finally, there remains the question, how long the minimal interval between two subsequent measurements should be. In conclusion, these unresolved questions have to be answered in relevant prospective studies, before recommending this technique for routine clinical application.

The influence of occlusion time on measuring respiratory resistance and compliance in infants with bronchiolitis.

The passive, single-breath, flow-volume technique is a simple method for measuring the resistance (Rrs) and the compliance (Crs) of the respiratory system in infants. So far, the potential influence of end inspiratory occlusion time on these measurements has not been investigated. We measured Rrs and Crs in 36 infants and toddlers with bronchiolitis; in each child, a spectrum of nine fixed occlusion times, ranging from 90 to 600 ms, was applied in random sequence. Increasing the duration of occlusions from 90 to 275 ms resulted in marked stepwise changes of measured Rrs and Crs; occlusions longer than 275 ms, however, produced highly reproducible measurements, as expressed 1) by minimal absolute differences between measured values at subsequent occlusion times and 2) by minimal percentage changes of measured values from one occlusion time to the next. There was no influence of age on the results; reproducible measurements were made in children as old as 1.5 y. This suggests that, in infants with bronchiolitis, 1) occlusions between 300 and 450 ms might be ideal for obtaining reliable measurements, and 2) the age range for applying this method can be extended into the 2nd y of life.

[Modification of pediatric lung function measurement by antibacterial filters]. / Die Beeinflussung der pädiatrischen Lungenfunktionsmessung durch antibakterielle Filter.

The risk of cross-infection by contaminated lung function equipment can be reduced by the use of antibacterial filters. These filters, however, should have no significant influence on flow measurements. We investigated the effect of a new filter (Pall PF 30) on lung function measurements in 92 children and adolescents with bronchial asthma and cystic fibrosis. In randomized sequence, flow-volume curves and spirometry were registered in the whole body plethysmograph. Values measured with filter correlated closely to those registered without; individual values remained close to the line of identity. With high flow rates, however, there was a minimal tendency towards lower measurements with filter; this damping effect was flow-dependent and remained of a clinically insignificant dimension.

[Modification of pediatric lung function measurement by antibacterial filters]. / Die Beeinflussung der pädiatrischen Lungenfunktionsmessung durch antibakterielle Filter.

The risk of cross-infection by contaminated lung function equipment can be reduced by the use of antibacterial filters. These filters, however, should have no significant influence on flow measurements. We investigated the effect of a new filter (Pall PF 30) on lung function measurements in 92 children and adolescents with bronchial asthma and cystic fibrosis. In randomized sequence, flow-volume curves and spirometry were registered in the whole body plethysmograph. Values measured with filter correlated closely to those registered without; individual values remained close to the line of identity. With high flow rates, however, there was a minimal tendency towards lower measurements with filter; this damping effect was flow-dependent and remained of a clinically insignificant dimension.

[The effect of occlusion time in the measurement of compliance and resistance of the respiratory system using passive expiration in infants]. / Einfluss der Verschlusszeit bei Messung der Compliance und Resistance des respiratorischen Systems mittels passiver Exspiration bei Säuglingen.

In a pilot study we examined the influence of occlusion time on compliance and resistance of the respiratory system in 17 infants. The values were calculated from a passive expiratory flow-volume-curve. Findings suggest that the ideal occlusion time is 300 to 400 msec.

[Bronchial reactivity in clinically symptom-free adolescent patients with asthma]. / Bronchiale Reaktivität bei klinisch beschwerdefreien jugendlichen Asthmapatienten.

More than half of the pediatric asthma population will become symptomfree during adolescence. We evaluated non-specific airway reactivity by cold air challenge in 42 symptomfree asthma patients, age 8 to 18 years, one year after termination of their anti-asthmatic medication. Twenty-one patients showed a normalized bronchial reactivity, 16 were found to be hyperreactive, and 5 presented with a borderline response. When compared to the normoreactive group, the hyperreactive subjects showed the following statistically significant differences: 1) more allergy by RAST and history (16/16 vs 14/21, p less than 0.05); 2) a significant reduction of mid- and endexpiratory flowrates in baseline lung-function measurements (% pred); maximum expiratory flow at 50% vital capacity: 75% vs 96%, p less than 0.01; maximum expiratory flow at 25% of vital capacity: 71% vs 102%, p less than 0.005). In conclusion, more than one third of our clinically symptom-free patients showed persisting bronchial hyperreactivity; 50% presented with a normalised bronchial response.

Influence of the "squeeze jacket" on lung function in young infants.

The possible influence of the "squeeze jacket" on measurements of lung function in young infants was examined in 29 infants. In 19 infants, a comparison was made between jacket off and jacket on with the arms held inside the jacket. With the jacket on (arms inside), we found a significant reduction in thoracic gas volume (TGV). Passive compliance of the respiratory system (Crs) was also significantly decreased, while the resistance of the respiratory system (Rrs) was significantly increased. An additional 10 infants were studied comparing jacket off with jacket on (arms outside) and jacket on (arms inside). TGV was significantly less with the jacket on (arms inside) compared to jacket off and jacket on (arms outside), while Rrs and mouth pressure at end-inspiratory occlusion (Pm) were significantly increased. There was no difference between jacket off and jacket on (arms outside). These observations suggest that the squeeze jacket with the arms held at the infant's side inside the jacket exerts a restricting effect on chest and abdominal wall movement and leads to errors in the measurements. To avoid these potential errors, measurements should be made without the jacket on or with the arms held outside the jacket.

[C-reactive protein and blood picture parameters in the early diagnosis of infection in children with surgical diseases]. / C-reaktives Protein und Blutbildparameter für Infektionsfrühdiagnostik chirurgisch-kranker Kinder.

Since its detection fifty years ago, CRP is known as prototype of the acute-phase-proteines. It is a more sensitive, then specific indicator for bacterial infections. We found that CRP in accordance with clinical symptoms and the neutrophil-cell-index (I. S-ratio) makes a good prediction for early diagnosis of infections. Caution has to be payed in immediate post-operative phase, because the surgical trauma by itself can increase CRP-values.

["Essential hypernatremia" as a result of on increased osmoreceptor threshold in a boy with Pierre-Robin disease and corpus callosum agenesis]. / "Essentielle Hypernatriämie" infolge erhöhter Osmorezeptorenschwelle bei einem Knaben mit Mb. Pierre-Robin und Balkenagenesie.

Hypernatremia was found as a cause of recurrent fever episodes in a 18 month old boy with Mb, Pierre-Robin and agenesia of the corpus callosum. We found values of serum-sodium until 160 mVal/l. Examinations of the osmotic regulation showed a so called "essential hypernatremia" without polyuria and polydipsi. Therefore must be responsible a defect of the osmotic center and thirst center in the hypothalamic area. As therapy a diet of 1000 ml = 1000 kcal = 100 mg Sodium/d. was successful.

[The chronically altered appendix in children. Cooperative work of the Austrian Society for Pediatric Surgery]. / Die "chronisch veränderte" appendix beim kind. Gemeinschaftsarbeit der Osterreichischen Gesellschaft für Kinderchirurgie.

In this multicentric study the anamnestic data and parents questionaires of 2-29 children were evaluated, whose appendix vermiformis at the time of operation showed no signs of inflammation. 31,1% macroscopically showed cicatrisation or fasciation, in 13,7% other enteral or gynaecological (1%) findings were present. In 1194 of the cases of patho-histological examination of the appendix had been made of which 36.4% were negative, 37.7% showed cicatrisation, 15,0% oxyuriasis and 10,4% coproliths. In the discussion of the significance of the chronically altered non-inflamed appendix we compared patients with and without macroscopical or microscopical alterations. We came to the conclusion that the probability-index as to sex, duration of symptoms, complexity of symptoms, incidence of postoperative well-being, proved the chronically altered appendix not to be an illness per se, but the result of spontaneously arrested inflammation. Since the rate of children admitted with a perforated appendix is high (15-20%) in comparison with the rate of complications after removal of non-inflamed appendices (2,9%), we believe that according to the diagnostical problems the principle can be maintained: in dubio pro operatione.