| 摘要 |
<p>Disclosed is a system for detecting the presence of a right-to-left pulmonary shunt in a patient. The system includes an indicator delivery system having an outlet located in a vein of the patient in blood flow communication with the right side of the heart and actuable to deliver a fluorescing biocompatible indicator into the vein such that the indicator will arrive at the right side of the heart within an anticipated transit time. The system also includes at least one optical sensor comprising a plurality of photodiode emitter energisable to generate light at the excitation radiation wavelength of the fluorescing indicator and a like number of photodetectors located in the housing of the sensor to detect light emitted from the fluorescing indicator at a second wavelength. The photodetectors are positioned on the opposite side of a tissue-receiving space from the photodiode emitters. The system also includes a monitor/controller for cueing actuation of the indicator delivery system, commence timing of the anticipated indicator transit time, display indicator dilation curves and, when a shunt is detected, to calculate and shunt conductance ratio from indicator dilution curves.</p> |
