• Resp Care · Mar 2005

    Comparative Study

    A laboratory evaluation of 2 mechanical ventilators in the presence of helium-oxygen mixtures.

    • Melissa K Brown and David C Willms.
    • Respiratory Therapy Program, Department of Health Sciences, Grossmont Community College, El Cajon, California, USA. mbrown20@cox.net
    • Resp Care. 2005 Mar 1;50(3):354-60.

    BackgroundHelium-oxygen (heliox) mixtures are being used more frequently with mechanical ventilators. Newer ventilators continue to be developed that have not yet been evaluated for safety and efficacy of heliox delivery. We studied the performance of 2 previously untested ventilators (Servo-i and Inspiration) during heliox administration.MethodsWe measured tidal volume (V(T)) delivery, gas blending, gas analyzing, and pressure stability in the presence of heliox. A heliox (80% helium/20% oxygen) tank was attached to the 50-psi air inlet. We compared the set V(T) (ie, set on the ventilator) and the exhaled V(T) (measured by the ventilator) to the delivered V(T) (measured with a lung model). Pressure measurements were also evaluated. We also compared the ventilator-setting fraction of inspired oxygen (F(IO(2))) to the F(IO(2)) measured by the ventilator and the F(IO(2)) measured with a supplemental oxygen analyzer.ResultsHeliox significantly affected both the exhaled V(T) measurement and the actual delivered V(T) (p < 0.001) with both the Servo-i and the Inspiration. Neither peak inspiratory pressure (in the pressure-controlled ventilation mode) nor positive end-expiratory pressure were adversely affected by heliox with either ventilator. Introducing heliox into the gas-blending systems caused only a small error in F(IO2) delivery and monitoring.ConclusionsBoth Ventilators cycled consistently with heliox mixtures. In most cases, actual delivered V(T) can be reliably calculated if the F(IO2) and the set V(T) or the measured exhaled V(T) is known. With the Servo-i, at high helium concentrations the exhaled V(T) measurement was unreliable and caused a high-priority alarm condition that couldn't be disabled. A supplemental oxygen analyzer is not necessary with either device for heliox applications.

      Pubmed     Free full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…