Variability in uptake efficiency for pulsed versus constant concentration delivery of inhaled nitric oxide

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• 作者：Andrew R Martin (1) (4)
  Chris Jackson (1) (5)
  Ira M Katz (2) (3)
  Georges Caillibotte (2)
  
• 关键词：Lung model ; Trumpet model ; Medical gas ; Nitric oxide ; Gas transport ; Conducting airways ; Mixing ; Dispersion ; Bolus ; Pulse
• 刊名：Medical Gas Research
• 出版年：2014
• 出版时间：December 2014
• 年：2014
• 卷：4
• 期：1
• 全文大小：701 KB
• 作者单位：Andrew R Martin (1) (4)
  Chris Jackson (1) (5)
  Ira M Katz (2) (3)
  Georges Caillibotte (2)
  
  1. Delaware Research and Technology Center, American Air Liquide, Newark, DE, USA
  4. Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
  5. 99 Fieldsend, Beaconsfield, QC, H9W 5J2, Canada
  2. Medical Gases Group, Air Liquide Santé International, 1 chemin de la Porte des Loges, Les Loges-en-Josas, 78354, France
  3. Department of Mechanical Engineering, Lafayette College, Easton, PA, USA
  
• ISSN：2045-9912

文摘

Background Nitric oxide (NO) is currently administered using devices that maintain constant inspired NO concentrations. Alternatively, devices that deliver a pulse of NO during the early phase of inspiration may have use in optimizing NO dosing efficiency and in extending application of NO to long-term use by ambulatory, spontaneously breathing patients. The extent to which the amount of NO delivered for a given pulse sequence determines alveolar concentrations and uptake, and the extent to which this relationship varies with breathing pattern, physiological, and pathophysiological parameters, warrants investigation. Methods A mathematical model was used to analyze inhaled nitric oxide (NO) transport through the conducting airways, and to predict uptake from the alveolar region of the lung. Pulsed delivery was compared with delivery of a constant concentration of NO in the inhaled gas. Results Pulsed delivery was predicted to offer significant improvement in uptake efficiency compared with constant concentration delivery. Uptake from the alveolar region depended on pulse timing, tidal volume, respiratory rate, lung and dead space volume, and the diffusing capacity of the lung for NO (DLNO). It was predicted that variation in uptake efficiency with breathing pattern can be limited using a pulse time of less than 100?ms, with a delay of less than 50?ms between the onset of inhalation and pulse delivery. Nonlinear variation in uptake efficiency with DLNO was predicted, with uptake efficiency falling off sharply as DLNO decreased below ~50-60?ml/min/mm Hg. Gas mixing in the conducting airways played an important role in determining uptake, such that consideration of bulk convection alone would lead to errors in assessing efficiency of pulsed delivery systems. Conclusions Pulsed NO delivery improves uptake efficiency compared with constant concentration delivery. Optimization of pulse timing is critical in limiting intra- and inter-subject variability in dosing.