RESEARCH ARTICLE


Mechanical Ventilator for Delivery of 17O2 in Brief Pulses



J.E Baumgardner*, a, b, E.A Mellonc, D.R Tailorc, K Mallikarjunaraoc, A Borthakurc, R Reddyc
a Oscillogy® LLC, Folsom, PA 19033, USA
b Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA 19104-4283, USA
c Metabolic Magnetic Resonance Research and Computing Center, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA


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Creative Commons License
© Baumgardner et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA 19104-4283, USA; E-mail: jbaumgardner@oscillogy.com


Abstract

The 17O nucleus has been used recently by several groups for magnetic resonance (MR) imaging of cerebral metabolism. Inhalational delivery of 17O2 in very brief pulses could, in theory, have significant advantages for determination of the cerebral metabolic rate for oxygen (CMRO2) with MR imaging. Mechanical ventilators, however, are not typically capable of creating step changes in gas concentration at the airway. We designed a ventilator for large animal and human studies that provides mechanical ventilation to a subject inside an MR scanner through 25 feet of small-bore connecting tubing, and tested its capabilities using helium as a surrogate for 17O2. After switching the source gas from oxygen to helium, the 0-90% response time for helium concentration changes at the airway was 2.4 seconds. The capability for creating rapid step changes in gas concentration at the airway in large animal and human studies should facilitate the experimental testing of the delivery 17O2 in brief pulses, and its potential use in imaging CMRO2.