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BACKGROUND: The guidelines to conduct and interpret conventional pulmonary function (PFT) tests are frequently reviewed and updated. However, the quality assurance and quality control (QA/QC) guidelines for respiratory oscillometry testing remain limited. QA/QC guidelines are essential for oscillometry to be used as a diagnostic pulmonary function test (PFT) in a clinical setting. METHODS: We developed a QA/QC protocol shortly after oscillometry was introduced in our laboratory as part of a clinical study. The first clinical study began after the research personnel completed 3 h of combined didactic and hands-on training and establishment of a standard operating protocol (SOP) for oscillometry testing. All oscillometry tests were conducted using the initial SOP protocol from October 17, 2017, to April 6, 2018. At this time, the first QA/QC audit took place, followed by revisions to the SOP, the addition of a QA/QC checklist, and the development of a 12-h training program. A second audit of oscillometry tests was conducted from April 9, 2018, to June 30, 2019. Both audits were completed by a registered cardiopulmonary technologist from the Toronto General Pulmonary Function Lab. RESULTS: The first audit evaluated 197 paired oscillometry-PFT tests and found 10 tests (5.08%) to be invalid, with a coefficient of variation > 15%. The second audit examined 1,930 paired oscillometry-PFT tests; only 3 tests (0.16%) were unacceptable, with a coefficient of variation > 15%. Improvement in QA/QC was significantly better compared to the first audit (P < .001). CONCLUSIONS: Although oscillometry requires minimal subject cooperation, application of the principles that govern the conduct and application of a PFT are important for ensuring that oscillometry testing is performed according to acceptability and reproducibility. Specifically, the inclusion of a SOP, a proper training program, a QA/QC checklist, and regular audits with feedback are vital to ensure that oscillometry is conducted accurately and precisely.

ObjectiveTo investigate the relationship between breastfeeding and the development of pediatric asthma.MethodsA systematic review and meta-analysis was conducted with MEDLINE, EMBASE, CINAHL and ProQuest Nursing and Allied Health source databases. Retrospective/prospective cohorts in children <18 years old with breastfeeding exposure reported were included. The primary outcome was a diagnosis of asthma by a physician or using a guideline-based criterion. A secondary outcome was asthma severity.ResultsForty-two studies met inclusion criteria. Thirty-seven studies reported the primary outcome of physician/guideline-diagnosed asthma, and five studies reported effects on asthma severity. Children with longer duration/more breastfeeding compared to less have a lower risk of asthma (OR=0.84; 95% CI: 0.75–0.93, I2=62.4%). Similarly, a lower risk of asthma was found in children who had more exclusive breastfeeding versus less exclusive breastfeeding (0.81; 0.72–0.91, I2=44%). Further stratified analysis of different age groups demonstrated a lower risk of asthma in the 0–2 age group (0.73; 0.63–0.83) and the 3–6 age group (0.69; 0.55–0.87), there was no statistically significant effect on the 7+ age group.ConclusionThe finding suggests that the duration and exclusivity of breastfeeding are associated with a lower risk of asthma in children less than seven years of age.

BackgroundMarkers of idiopathic pulmonary fibrosis (IPF) severity are based on measurements of forced vital capacity (FVC), diffusing capacity (DLCO) and CT. The pulmonary vessel volume (PVV) is a novel quantitative and independent prognostic structural indicator derived from automated CT analysis. The current prospective cross-sectional study investigated whether respiratory oscillometry provides complementary data to pulmonary function tests (PFTs) and is correlated with PVV.MethodsFrom September 2019 to March 2020, we enrolled 89 patients with IPF diagnosed according to international guidelines. We performed standard spectral (5–37 Hz) and novel intrabreath tracking (10 Hz) oscillometry followed by PFTs. Patients were characterised with the gender-age-physiology (GAP) score. CT images within 6 months of oscillometry were analysed in a subgroup (26 patients) using automated lung texture analysis. Correlations between PFTs, oscillometry and imaging variables were investigated using different regression models.FindingsThe cohort (29F/60M; age=71.7±7.8 years) had mild IPF (%FVC=70±17, %DLCO=62±17). Spectral oscillometry revealed normal respiratory resistance, low reactance, especially during inspiration at 5 Hz (X5in), elevated reactance area and resonance frequency. Intrabreath oscillometry identified markedly low reactance at end-inspiration (XeI). XeI and X5in strongly correlated with FVC (r2=0.499 and 0.435) while XeI was highly (p=0.004) and uniquely correlated with the GAP score. XeI and PVV exhibited the strongest structural-functional relationship (r2=0.690), which remained significant after adjusting for %FVC, %DLCO and GAP score.InterpretationXeI is an independent marker of IPF severity that offers additional information to standard PFTs. The data provide a cogent rationale for adding oscillometry in IPF assessment.

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