title: Sequential gas delivery provides precise control of alveolar gas exchange.
abstract: Of the factors determining blood gases, only alveolar ventilation (VA) is amenable to manipulation. However, current physiology text books neither describe how breath-by-breath VA can be measured, nor how it can be precisely controlled in spontaneously breathing subjects. And such control must be effected independent of minute ventilation (VE) and the pattern of breathing. Control of VA requires the deliberate partition of inhaled gas between the alveoli and the anatomical deadspace. This distribution is accomplished by sequential gas delivery (SGD): each breath consists of a chosen volume of 'fresh' gas followed by previously exhaled gas. Control of VA through SGD is a simple, inexpensive, yet powerful tool with many applications. Here we describe how to implement SGD, how it precisely controls VA, and consequently how it controls arterial blood gases.
authors: Department of Anesthesiology University Health Network, and Department of Physiology, University of Toronto, Toronto, Canada. Electronic address: joe.fisher@utoronto.ca.
authors: Joseph A
authors: JA
authors: Fisher
authors: Department of Biomedical and Molecular Sciences, Queens University, Kingston, Canada.
authors: Steve
authors: S
authors: Iscoe
authors: Department of Anesthesiology University Health Network, and Department of Physiology, University of Toronto, Toronto, Canada.
authors: James
authors: J
authors: Duffin
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism; D006801:Humans; D008955:Models, Cardiovascular; D011650:Pulmonary Alveoli / Q000378:metabolism*; D011659:Pulmonary Gas Exchange / Q000502:physiology*
chemical_list: D002248:Carbon Monoxide
keywords: Alveolar ventilation; Anesthetic clearance; Carbon monoxide poisoning; Cardiac output; Isocapnia; Rebreathing; Sequential gas delivery; isoxia