Method and apparatus to attain and maintain target arterial blood gas concentrations using ramp sequences

Abstract

An apparatus and method for controlling the end tidal partial pressure of a gas X in a subject's lung, and to the use of such an apparatus and method for research, diagnostic and therapeutic purposes, wherein the method consists of: obtaining input of a series of logistically attainable PetX values for a series of respective breaths: determining an amount of gas X required to be inspired by the subject in an inspired gas to target the PetX for each of said respective breaths: and controlling a gas delivery device to deliver the amount of gas in a volume of gas delivered to the subject in each of said respective breaths to target the respective PetX for that breath.

Description

FIELD OF THE INVENTION[0001]The present invention relates to an apparatus and method for controlling end tidal gas partial pressures in spontaneously breathing or ventilated subjects and to the use of such an apparatus and method for research, diagnostic and therapeutic purposes.BACKGROUND OF THE INVENTION[0002]Techniques for controlling end-tidal partial pressures of carbon dioxide, oxygen and other gases are gaining increasing importance for a variety of research, diagnostic and medicinal purposes. Methods for controlling end tidal pressures of gases have gained particular importance as a means for manipulating arterial levels of carbon dioxide (and also oxygen), for example to provide a controlled vasoactive stimulus to enable the measurement of cerebrovascular reactivity (CVR) e.g. by MRI.[0003]Conventional methods of manipulating arterial carbon dioxide levels such as breath holding, hyperventilation and inhalation of fixed concentration of carbon dioxide balanced with medical ...

AI Technical Summary

Benefits of technology

[0131]The time course of predicted mixed-venous gases is used to compute the series of inspired gas mixtures required to realize the target end-tidal partial pressures of gases. In this way, assuming that the end-tidal partial pressures of gases adhere to the targets allows prediction of the mixed-venous gases, and prediction of the mixed-venous gases

Problems solved by technology

Conventional methods of manipulating arterial carbon dioxide levels such as breath holding, hyperventilation and inhalation of fixed concentration of carbon dioxide balanced with medical air or oxygen are deficient in their ability to rapidly and accurately attain targeted arterial carbon dioxide partial pressures for the purposes of routinely measuring vascular reactivity in a rapid and reliable manner.

Previous attempts at controlling the end-tidal partial pressures of gases have failed to account for these com

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