Alternative Treatments for Severe Status Asthmaticus

Shamblin, Clayton; Divietro, Matthew; Strange, Charlie; Huggins, John T.

doi:10.1378/chest.1389315

Cited by 1 publication

(2 citation statements)

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“…Crim et al found a poor relationship (Pearson’s r ≤0.16) between emphysema extent and Rrs and Xrs measured by IOS in a large study but they did not analyze within-breath changes [20]. Timmins et al also reported that there was no correlation between emphysema extent and ΔX6 measured by their in-house monofrequency FOT device [21]. Consistent with these reports, there was no correlation in univariate analysis in the present study, but multivariate analysis revealed that severe emphysema related to the high EFL index, indicating the need to control for confounding factors.…”

Section: Discussionmentioning

confidence: 99%

“…As airway obstruction increases in COPD, Rrs rises and becomes more frequency dependent, especially at lower frequencies [22], implying that R5 is supposed to be a measure of airway caliber. Timmins et al also found a strong correlation between R6 and EFL index [21], while Dellacà et al confirmed that ΔR5, in contrast to ΔX5, was not associated with EFL [1]. …”

Section: Discussionmentioning

confidence: 99%

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Predictors of expiratory flow limitation measured by forced oscillation technique in COPD

et al. 2014

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BackgroundExpiratory flow limitation (EFL) during tidal breathing is common in patients with severe COPD, and a major determinant of dynamic hyperinflation and exercise limitation. EFL can be measured by the forced oscillation technique (FOT); however, the relevance to clinical parameters is not fully understood. We hypothesized that emphysema extent and pulmonary function would contribute independently to the degree of EFL.MethodsBroadband frequency FOT and pulmonary function tests were performed in 74 patients with COPD to derive respiratory system resistance (Rrs) and reactance (Xrs), and the EFL index as expressed by the differences between inspiratory and expiratory phases of Xrs at 5 Hz (ΔX5). Emphysema extent was measured by high-resolution computed tomography and scored.ResultsOn the basis of the median value of ΔX5 (0.55 cmH2O/L/s), patients were classified into a high or low EFL index group. In multivariate regression analyses, a high EFL index was independently predicted by emphysema score, peripheral airway obstruction (forced expiratory flow between 25% and 75% of forced vital capacity), hyperinflation (functional residual capacity), and airway caliber (whole-breath Rrs at 5 Hz).ConclusionsEFL measured by FOT is a global measure of COPD that has separable etiologies and is useful for evaluating the disease condition.

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Section: Discussionmentioning

confidence: 99%