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We describe a method to determine the phase III slope for the purpose of calculating indexes of ventilation heterogeneity, S(acin) and S(cond), from the multiple breath nitrogen washout test (MBNW). Our automated method applies a recursive, segmented linear regression technique to each breath of the MBNW test and determines the best point of transition, or(More)
The paper reports on a comparative evaluation of 10 rapid malaria tests available in South Africa in 1998: AccuCheck (AC, developmental), Cape Biotech (CB), ICT Malaria Pf (ICT1) and Pf/Pv (ICT2), Kat Medical (KAT), MakroMal (MM), OptiMAL (OP), ParaSight-F (PS), Quorum (Q), Determine-Malaria (DM). In a laboratory study, designed to test absolute detection(More)
Rapid arterial O(2) desaturation during apnea in the preterm infant has obvious clinical implications but to date no adequate explanation for why it exists. Understanding the factors influencing the rate of arterial O(2) desaturation during apnea (Sa(O)₂) is complicated by the non-linear O(2) dissociation curve, falling pulmonary O(2) uptake, and by the(More)
In order to understand the pathophysiology of diseases such as asthma and chronic obstructive pulmonary disease, it is essential to measure the mechanical properties of the airways. Currently, there are no methods to measure and quantify in vivo airway compliance in humans. In order to develop a method, we generated a curve-fitting algorithm that combines(More)
Airway distensibility appears to be unaffected by airway smooth muscle (ASM) tone, despite the influence of ASM tone on the airway diameter-pressure relationship. This discrepancy may be because the greatest effect of ASM tone on airway diameter-pressure behavior occurs at low transpulmonary pressures, i.e., low lung volumes, which has not been(More)
BACKGROUND Exacerbations of asthma are thought to be caused by airflow obstruction resulting from airway inflammation, bronchospasm, and mucus plugging. Histologic evidence suggests the small airways, including acinar air spaces, are involved; however, this has not been corroborated in vivo by measurements of peripheral small-airway function. OBJECTIVE We(More)
A new technique has been developed to determine in vivo airway compliance in humans that is specific to airway size and transpulmonary pressure, and can be represented as a three-dimensional surface. As yet, the ability of this technique to detect changes in specific airway compliance with disease status has not been demonstrated. The aim of this study was(More)
RATIONALE Brief recurrent apneas in preterm infants and adults can precipitate rapid and severe arterial O(2) desaturation for reasons that remain unclear. OBJECTIVES We tested a mathematically derived hypothesis that when breathing terminates apnea, mixed-venous hypoxemia continues into the subsequent apnea; as a result, there is a surge in pulmonary(More)
Preterm infants have a reduced pulmonary diffusing capacity that has been invoked to explain rapid arterial O(2)-desaturation during apnea, despite little evidence to support this view. We explored the role of diffusion limitation on O(2)-desaturation during apnea by developing a mathematical model of gas exchange in which O(2) dynamically loads the blood(More)