An Algebraic Solution to Dead Space Determination According to Fowler's Graphical Method

Effects of pulmonary inhalation on hyperpolarized krypton-83 magnetic resonanceT1relaxation

“…Furthermore, the presence of many surface-to-volume ratios at different generations of branching of the airways can not be quantified. Even in the simplified model, the largest contribution to the hp 83 Kr signal will originate from the alveolar region of the lung due to the small total overall volume of the conducting airways, which typically contribute 5% or less to the overall lung volume (Fowler, 1948; Heller et al, 1999). Nevertheless, scheme 2 should direct hp 83 Kr more towards the proximal airways than scheme 1 and scheme 2 is therefore expected to provide the slowest longitudinal relaxation.…”

Fractionated Exhaled Breath Condensate Collection Shows High Hydrogen Peroxide Release in the Airways

“…Since there is no gas exchange in the airways, no CO 2 is exhaled from this region; therefore this region is determined the dead space of the lung. The exhaled CO 2 profile was analyzed according to the protocol of Fowler (21,22) and three different threshold volumes were derived, as indicated in Figure 1. The phase-1 dead space (DS Ph1 ) is specific to the conducting airway volume, which does not contain mixing air (CO 2 ) from the lung periphery.…”

Effects of ventilation on the collection of exhaled breath in humans

“…However, breath holding can only be used for the analysis of a single breath and may increase nasal contributions for certain molecules (1,19). Modeling carbon dioxide concentrations in the alveoli and airways suggests that monitoring the concentrations of mixed expired carbon dioxide may provide a close estimation of the anatomic dead space (13,17,45). Schubert et al (35) have reported the use of a carbon dioxide-sensitive switch to allow the capture of the end-tidal fraction when collecting breath from mechanically ventilated patients.…”