ISSN:
1573-2614
Keywords:
nitric oxide
;
high frequency oscillatory ventilation
;
chemiluminescence assay
;
electrochemical assay
;
mechanical ventilation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Computer Science
,
Medicine
Notes:
Abstract Objective. The objective of this study is to determine the accuracy andprecision of chemiluminescence and electrochemical nitric oxide (NO)measurements and accuracy of NO dosage with electronic mass flow controllers(MFC) versus rotameters during NO inhalational therapy. Methods. NO flow wasdelivered to a high frequency oscillator and mixed with ventilator flow. NOand NO2 concentrations were measured simultaneously with astandard chemiluminescence analyzer and a modified electrochemical analyzer.Dosage accuracy was assessed with gas flows adjusted with either MFC’sor rotameters. Accuracy of both analyzers was validated with both NO andventilator flow regulated with a MFC. Results. In dry air, without pulsatilepressure, MFC controlled NO and ventilator flow resulted in an accuracyexpressed as the ratio of calculated concentration to measured concentration(RCM) of 0.995 (CI: 0.983–0.988) when measured with chemiluminescence.When the ventilator rotameter was used instead of a MFC, RCM was 0.856 (CI:0.835–0.877). With a rotameter for both NO and ventilator flow, RCMincreased to 1.175 (CI: 0.793–1.740) with an increase of confidenceinterval limits. Chemiluminescence was sensitive to humidification of theventilatory gases (p 〈 0.05), slightly sensitive to the addition ofoxygen and to pulsatile pressure (not significant). RCM obtained with themodified electrochemical analyzer was in close agreement withchemiluminescence RCM, although 95% CI were wider withelectrochemical analysis. Conclusions. During high frequency oscillatoryventilation (HFOV), standard rotameter flow control of both NO andventilator flow results in unpredictable NO concentrations that would beclinically unacceptable. When one MFC was used for NO flow control, withventilator flow controlled with a rotameter, this resulted in moderatedosage accuracy. To achieve a still higher accuracy, MFC flow control forboth NO and ventilator flow is indicated. During HFOV, standardchemiluminescence analyzers cannot be considered to be the gold standard fordetermination of the NO concentration delivered. Measurement of NOconcentration may not be mandatory for determination of inhaled NO doseduring HFOV, but may be used to monitor for unsafe or unwanted events.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007476223906
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