The following is a brief graphic tour of the BIS-T1 trial system, which may be downloaded at no charge and distributed freely.
These are "screen dumps" of the Biofeedback Incentive Systemtm "Virtual Instrument" developed in the National Instruments LabVIEW environment.
The first is the setup screen. The various parameters noted are input to create an inspiration / expiration waveform. The "Start" button takes you to the patient interactive screen.
This screen below shows the programmed inspiration / expiration analog. In addition to Tidal Volume and Respiratory Rate, note there are four waveform components:
Note this is a Volume versus Time display. The programmable Inspiration / Expiration visual analog is indicated. The commercial version of BIStm provides curvilinear waveform options for more definitive waveform shaping. Note the patient performance line is inactive.
The following picture demonstrates deficient patient performance. Note that on inspiration the inspiratory flow is delayed and slower than the program line, and that inspiration stops before an adequate Tidal Volume has been achieved. Also, the expiratory flow is faster than programmed.
The following picture demonstrates correct inspiratory flow, and the patient achieving the programmed Tidal Volume. However, the expiratory phase is too slow, and proper exhalation has not been achieved.
Note that on inspiration the real time patient flow / volume is correct, and the patient achieves the desired Tidal Volume. Not shown, because the respiratory cycle is completed, is a blinking cursor on the program line. This provides a real time target for the patient to follow and to correct performance, i.e. the is a visual biofeedback prompting system.
Note however this prompting analog may be dynamically altered by the controls along the bottom of the screen:
The "Refresh [Esc]" button resets the system to zero, and is used to coordinate the program with the patient's breathing.
The "Pause [F1]" button halts the display, to permit discussion with the patient, and from there the "Print [F2]" button activates the printer.
The following picture demonstrates the optional "Phantom Line" error limit detection system. Plus and Minus error limits may be defined, as a percentage of the Tidal Volume. Note the +/- Error Limits around the programmed prompting analog. This permits definable limits of acceptable patient performance, i.e. a performance quality control method. For precise research needs these error limits may be set to a limited error tolerance.
The following picture shows performance error detection in early inspiration, and later in mid expiration.
The following picture shows patient performance to be within the defined error specifications. Note that inspiration is almost perfect, and that expiration is less perfefect but still within the defined +/- 20% limits. Note that expiration would not have been satisfactory if the error limits were +/- 10%.
Further examples of the BIS-T1 Virtual Instrument may be found in the "New and What's News" section under "Projects." Examples of the BIStm system with more definitive curvilinear waveforms my be seen in the Biofeedback Incentive Systemtm section.