Should we use criteria or eyeballing to reject post-interruption tracings?

During the analysis of interrupter resistance (R(int))-measurements, most authors reject post-interruption tracings based on the shape of the pressure-time and flow-time curves. However, objective criteria for rejection are lacking. We aimed to formulate explicit rejection criteria that correspond to eyeballing the curve pattern (daily practice), in order to simplify the analysis. Inter-observer agreement within and between both methods was studied. Results obtained with the developed rejection criteria were compared to those of current practice (eyeballing) using 54 measurements (807 interruptions) of children with severe neurological impairment. Inter-observer agreement on rejection was similar using the criteria or eyeballing (85.6% vs. 82.8%). Using the criteria, more individual interruptions were rejected (43.4% vs. 29.8% using eyeballing), while discarding total measurements (<5 remaining interruptions) was similar (9.2% vs. 7.4% using eyeballing). Results using only the criteria for pressure-time curves were comparable to eyeballing. Outcome values were comparable between any of the used rejection methods and not rejecting at all. In this first detailed study on rejection of post-interruption tracings, explicit rejection criteria were developed. None of the rejection methods influenced the outcome value relevantly. However, rejection criteria can contribute to the standardization of the R(int) technique and simplify decision-making in daily practice.

House dust mite allergen reduction and allergy at 4 yr: follow up of the PIAMA-study.

Exposure to high allergen levels in early life is a risk factor for the development of allergy. We previously reported limited effects of mite allergen impermeable mattress covers in the prevention and incidence of asthma and mite allergy (PIAMA) cohort at the age of 1 and 2 yr. We now present the results of follow-up at 4 yr objectives. To examine the effects of early reduction of house dust mite (HDM) allergen exposure by means of mattress covers on the incidence of allergy and asthma symptoms in the PIAMA birth cohort at the age of 4 yr. High-risk children (allergic mother) were prenatally recruited and randomly allocated to three groups; receiving mite allergen impermeable mattress covers (n = 416), placebo covers (n = 394) or no intervention (n = 472). At 4 yr of age, atopy was assessed by questionnaire; specific Immunoglobulin E (IgE) to inhalant and food allergens was measured in serum. Dust samples collected from the children's mattresses were analysed for mite allergens. Dermatophagoides farinae1 allergen (Der f 1) levels in dust were reduced in the active group. However, Dermatophagoides pteronissinus 1 (Der p 1) levels, sensitization and atopic symptoms were similar in all groups. We found no effect of mite allergen impermeable mattress covers on sensitization and atopy at 4 yr. Moreover, the allergen reducing effects of the covers had disappeared for one of the two mite allergens that were measured.

Allergen exposure in infancy and the development of sensitization, wheeze, and asthma at 4 years.

BACKGROUND: The relationship between mite and pet allergen exposure in infancy and the subsequent development of sensitization and asthma is complex. OBJECTIVE: We prospectively investigated the effect of allergen exposure at 3 months of age on the development of sensitization, wheeze, and physician-diagnosed asthma in the first 4 years of life in a birth cohort of children with and without an atopic mother. METHODS: Children participated in the Prevention and Incidence of Asthma and Mite Allergy study. Allergen exposure at 3 months of age was determined from mattress dust samples. Specific IgE to inhalant allergens was measured at 4 years of age, and information about wheeze and physician-diagnosed asthma was collected with yearly questionnaires. RESULTS: Mite and cat allergen exposure in infancy were associated with an increased risk of specific sensitization to house dust mite and cat, respectively, at 4 years of age. There were borderline significant associations between cat allergen exposure and persistent wheeze in the total study population and between dog allergen exposure and persistent wheeze in children with a nonatopic mother. In children with an atopic mother, there was some indication of a positive association between mite allergen exposure and physician-diagnosed asthma. CONCLUSION: Early house dust mite and cat allergen exposure might lead to sensitization and, in case of cat allergen exposure, to persistent wheeze. Early mite and dog allergen exposure might lead to asthma and persistent wheeze, respectively, but only in subgroups defined by maternal atopy.

Interrupter resistance and wheezing phenotypes at 4 years of age.

It is difficult to distinguish young children with respiratory symptoms who will develop asthma from those with transient symptoms only. Measurement of interrupter resistance may help to identify children at high risk of asthma. The aim of this study is to compare interrupter resistance in 4-year-old children with different wheezing phenotypes. All children participated in the Prevention and Incidence of Asthma and Mite Allergy cohort, a prospective birth cohort of more than 4,000 children. At 4 years of age, data on interrupter resistance plus wheezing phenotype were available for 838 children. Mean interrupter resistance values (95% confidence interval) were 0.95 (0.93, 0.97), 0.95 (0.92, 0.98), 0.96 (0.87, 1.05), and 1.08 (1.02, 1.14) kPa.L(-1).second for never (n = 482), early transient (n = 236), late-onset (n = 22), and persistent (n = 98) wheezing phenotypes, respectively. Additional analyses were performed for children with atopic and nonatopic mothers separately. Both in children with atopic and nonatopic mothers, children with persistent wheeze had significantly higher interrupter resistance values than children with never and early wheeze. In conclusion, mean interrupter resistance values were higher in children with persistent wheeze as compared with children with never and early transient wheezing phenotypes.

Prospective evaluation of ileoanal pouch characteristics measured by barostat.

PURPOSE: The aim of this study was to evaluate pouch sensory and motor characteristics prospectively during the first postoperative year and to compare those with rectal characteristics. METHODS: Twelve patients with an ileoanal J-pouch were studied at 3 and 12 months postoperatively. The results were compared with those obtained in 12 healthy controls. Visceral compliance was assessed using an electronic barostat by a pressure distention procedure, during which sensitivity was also scored by visual analog scales. The response to a meal was assessed during set pressure. RESULTS: During the first postoperative year, pouch compliance increased significantly from 7.2 +/- 0.6 to 10.7 +/- 0.9 ml/mmHg (rectal compliance 10.6 +/- 1.1 ml/mmHg). The increase in pouch compliance significantly influences the 24-hour stool frequency (P = 0.42). Visceroperception scores remained unchanged. Postprandial decrease in intrabag volume was more pronounced in patients (45 +/- 13 percent at 3 months, 32 +/- 15 percent at 12 months) than in controls (9 +/- 6 percent, < 0.05), and residual postprandial bag volumes were significantly lower in patients at 3 months compared with patients at 12 months. CONCLUSIONS: Ileoanal pouch compliance increases significantly during the first postoperative year to values in the range of rectal compliance. The increase in pouch compliance is related to a decrease in 24-hour stool frequency. Postprandial bag volumes increase during the first postoperative year but remain significantly smaller than in the rectum. Pouch sensitivity does not change.