A.364 Mixing conditions during nitric oxide administration evaluated with fast response chemi-luminescence and capnography

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“…This fluctuation, which can be detected only by fast-response chemiluminescence apparatus results from the passage of the bolus past the sampling site for the inspired gas. As recently suggested, even fast-response chemiluminescence may underestimate rapid changes in NO concentrations [11]. If the NO bolus is small and moves with a high velocity, chemiluminescence apparatus with a response time between 0.5 and 1.5 s may be unable to provide accurate measurements of the true peak NO concentration.…”

“…If the NO bolus is small and moves with a high velocity, chemiluminescence apparatus with a response time between 0.5 and 1.5 s may be unable to provide accurate measurements of the true peak NO concentration. By using CO 2 as a tracer gas and infrared capnography with a response time of 350 ms, Stenqvist et al demonstrated that fast-response chemiluminescence (response time of 1.5 s) underestimates true peak NO concentrations when sampling at the Y piece during the inspiratory phase [11]. If this fluctuation is measured at different sites in the inspiratory limb, the peak concentration and its phase in relation to the respiratory cycle vary significantly.…”

Distribution of inhaled nitric oxide during sequential and continuous administration into the inspiratory limb of the ventilator

“…Because identical ventilatory and NO equipment was used in the lung model and in the patients, it can be assumed that the observed differences in tracheal NO concentrations were related to the differences in the volume of distribution and pulmonary uptake of NO. Recently it has been suggested that even fast-response chemiluminescence may underestimate rapid changes in NO concentrations [17]. If the NO bolus is small and moves with a high velocity, a chemiluminescence apparatus with a response time ranging between 0.5 and 1.5 s may be unable to provide accurate measurements of the true peak NO concentration.…”

“…If the NO bolus is small and moves with a high velocity, a chemiluminescence apparatus with a response time ranging between 0.5 and 1.5 s may be unable to provide accurate measurements of the true peak NO concentration. By using CO 2 as a tracer gas and infrared capnography characterized by a time-response of 350 ms, Stenqvist et al demonstrated that fast-response chemiluminescence (time-response of 1.5 sec) underestimates true peak NO concentrations when sampling at the Y-piece during the inspiratory phase [17].…”