InfoPFT: An algorithm for automatic interpretation of

InfoPFT: An algorithm for automatic interpretation of Pulmonary Function Tests by Pablo V Romero MD, PhD InfoPFT is a program that obtains relevant information from pulmonary function tests data, therefore helping doctors in charge of PFT laboratories in the elaboration of reports. It is important to keep in mind that InfoPFT works essentially with numerical data, and these data must have a minimum of reliability. The quality of functional tests has to be guaranteed by laboratory technicians and doctors in charge of the validation process. Daily calibrations, quality controls, and assessment of reproducibility are crucial for safety of information. Technicians must be trained and know the basic requirements for acceptable tests and data validity. Basically, InfoPFT operates in the following way: it imports the data exported by the measurement device computer, then shows the most relevant parameters in the screen, as well as MFV curve, and, once the doctor agrees, elaborates the report, which can be exported in several formats. This process can be performed on the same computer containing exploration software or, more usually, on a central computer connected to one or more exploration computer devices. In the first case, InfoPFT directly captures and processes the data exported in the exploration computer. In the second case, a small technician modulus (InfoPFtec) is usually installed in the exploration computer, for converting the exported data to a common *.PFT format, which is then read by InfoPFT program, either on a network server or simply brought to the doctor’s computer in a portable device (a pen drive for instance). Now we will see in detail the operation of InfoPFT program 1.

Installing InfoPFT

The first time InfoPFT program is opened Installation Setup must be configured. Several items appear when Setup menu is clicked (Figure 1): -

Installation: This part of the menu is accessible when the program opens for you to configure the basic setup:  Driver: Indicates the disk or device where the program has been installed. The default setting is “C:\” (Because the program is installed in C:\ProgramFiles).  Data Source: A check box appears listing the devices supported by the program, plus INFOPFT. As reports are usually produced on a computer other than an exploration device computer, the default format is INFOPFT, which uses data previously converted by the technician’s program (InfoPFtec, see below). If, on the contrary, the data received by the doctor’s computer is the raw data exported by the equipment computer the specific equipment must be selected on the list. Click on the appropriate item to save the selection.  Input/Output: Here you set the paths for the addresses of files to be read, figures (MEFV curves) and output for reporting. They must be complete (“C:\data” ; “C:\2014_06_15\curves” or “D:\reports\15.06.2014”, for instance)  Header: You can set the general header for your reports; there are three rows corresponding to a) Hospital or Center; b) Department and c) Name of the PFR lab.  Language: A check box appears showing the different languages available. When checked all labels are automatically translated to the selected language. A greater selection will be available if more languages are requested (at this time English, French, Catalan and Spanish are the available languages). Reports are written in the selected language.  Units: This program accepts different units for Weight (Kg or pounds), Height (m, cm or inches) and Functional Parameters (Classical: L, mmHg, cmH2O; or SI units: L, kPa, mMol). All parameters must respect the Units System selected.

Setup menu has some more options: Predicted: allows a choice of three options:  Default Predicted (ERS): Uses the set of European Respiratory Society equations (Standardized Lung Function Testing. Eur. Respir. J. 1993, 6, Supplement 16)  Default Predicted (GLI): Uses Global Lung Initiative predictive equations for spirometry parameters, ERS equations for other parameters  User choice: Uses the prediction values selected by the user in the exploration software. Signature: Name of the Doctor that validates and signs the report. When installation is complete you can open the first data file. At this time the “Install” option on the Setup menu will be deactivated. To change Install options you can exit the program and open it again. However, it is possible to modify Input/Output addresses without exiting the program: Option “Inbox” allows you to set the inputs for data and curves; option “Picture address” and “Report address” allows you to set the address for curves (input) and reports (output) respectively. Figure 1: Setup Pop-Up Menu

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Opening a patient file By clicking on the “Open File” Option in the File Pop-up menu all the files of a selected type contained in the Input Folder appear (if INFOPFT has been selected, text files with the

extension *.pft will be shown; otherwise *.txt, *.rtf, *.pdf, etc.., depending on the export format of the equipment). When the desired file is opened demographics①, parameters ② and MEFV curve ③ will appear, as well as the technicians’ messages④

Figure 2: Read data

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Modifying data At this time you can modify or add any data, (except the date of exploration) by using the menu function File > Modify. The screen changes to show a table with a list of parameters that you can modify or add. In this list, only parameters that are directly measured are shown, the rest of parameters will then be recalculated. You can also modify demographics data as well as patient’s conditions or cooperation, but not the technician’s notes, (you can also write on the Text Box, but we advise against it at this time, see below). Box cases that cannot be modified are in grey. At this time the screen appears as follows (Figure 3)

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DLCO is usually imported uncorrected. If Hemoglobin concentration has been measured, its value (in g/dl) has to be introduced as a modification; DLCO will be modified according to J. Cotes equation. Blood gases are not usually measured by respiratory function devices. Therefore, PaO2, PaCO2 and pH values must be introduced as modifications. Alveolar-arterial gradient is calculated according to barometric pressure. If Pbar is not available, a standard Pbar is assumed (750.06 mmHg or 100 kPa, according to the Standard Pressure definition recommended by IUPAC,

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1982). Note that units for partial pressures and barometric pressure must be in the units system selected (mmHg or kPa).

Figure 3: Modifying data

When the changes have been completed, push the button [Accept] and verify the changes have been transferred to the Text Box. Some changes are mandatory

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Producing the automatic report By clicking on the menu function Report > General an automatic report is produced and appears at the end of the numeric form. If the report is longer than the text box a lateral scroll bar appears showing the complete report and the figure simultaneously. The screen now appears as in Figure 4.

You can modify the text of the report directly on the screen, by changing, suppressing or adding anything you want. To assist in the more usual corrections (commonly related to clinical data, not accounted for by the program), you can elaborate a text of typical sentences that are saved in the “Setup” folder (see “installation instructions”). By clicking in the Menu Item “Report > Sentences>Select Sentence”, a box with sentences is opened and then you can click on the desired sentence and paste it at the appropriate place in the report (Ctrl+V). The “Sentences” menu also allows you to edit sentences with “Notebook” (some default sentences are given as examples).

Figure 4: Automatic Report

Three buttons on the right of the text box allow the report to be saved in three different formats: rich text format (RTF), portable document format (PDF), or MSWord document format (DOC) (see below).

5. Selecting typical Maximal Flow Volume Curve shapes With extreme exceptions, the shape of the MFVC cannot be detected from numerical parameters. InfoPFT offers the possibility of identifying some of the more typical shapes and relating them to the pathophysiological disorders they express. By clicking on the MFVC picture, several images appear at the top (MEFV branches) and bottom (MIFV branches) representing characteristic expiratory or expiratory shapes (see Figure 5). By clicking on the shape a black square appears around it indicating that this shape has been selected and a message box appears with the pathophysiological interpretation of the MFVC selected shape. If we do not agree with this interpretation, the shape can be de-selected by clicking on it again. Then the square box disappears, and the report will not take this shape into account. This operation can be done either before or after the automatic report is produced. If the selection is done before the automatic report, it must precede any modification of parameters (afterwards the picture is off, see Figure 3). If you select it after the report, it is advisable either to erase the report manually or to click on the menu File > Modify and then [Accept] in order to erase the report and do it again (otherwise a new, probably modified report will appear following the old one). One possible strategy, however, would be to keep the old report and select the one that gives the better diagnosis (and manually erase the other).

Figure 5: Typical morphologies of MEFV and MIFV loops of MFV curve (arrow represents the selected shape)

With few exceptions, only one inspiratory and one expiratory shape can be selected. To avoid reiterations, selection of a curve shape does not necessarily modify the report if the report has already identified the trouble. Furthermore, for the same reason the sentence can be different from the one shown in the message box.

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Saving reports

On the right of the text box, below the figure, three buttons indicate three ways of saving the report: -

Save RTF or Rich Text Mode saves the report to WordPad in text mode: This method does not require MSOffice, and allows changes to be made after the report has been saved (useful when reports are done by trainee doctors or for educational purposes and therefore must be validated afterwards). In order to simultaneously export the figure, place the cursor one or two lines below the signature and paste the figure by pressing Ctrl+V. The figure will appear at the end of the report. Size can be adjusted as usual. Then click on [Save RTF] button to export it. WordPad opens showing the report. You can center the figure with the “justify” button. Furthermore, this report can be fully post-edited with Open Office Writer freeware.

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Save PDF or Portable Document Format saves the file in Acrobat PDF mode: the MEFV figure is automatically adjusted to the blank space that is considered most suitable by the placement algorithm (Figure 6(b)). This form can include the Institution’s Logo in the left upper corner of the report. It cannot be post-edited, and for this reason it is the preferred form for digital reports. Save Doc requires MSOffice enabled for Macros: The figure is automatically placed in the top right-hand corner of the form inside a box that can be transferred and resized at the most convenient place chosen by the user (Figure 6(c)). After post-edition, the form can be print as PDF. Please be sure you have enabled word to accept macros* * Enable Word to accept macro-embedded documents 1. In Word click the Microsoft Office Button, then click Word Options. 2. Click Trust Center > Trust Center Settings > Macro Settings. 3. Click the radio button Enable all macros. 4. Click OK, twice.

Figure 6: Screen captures of reports obtained with RTF (a), PDF (b) and DOC (c) formats (without postediting)

(a) WordPad

(b) PDF pre-print WordPad

(b) MS Word WordPad

In addition to these three forms, you can save only the text report (to be included in a form developed by another program, clinical files, etc.). To save only the text, open the Menu Item “Report > Export” and a Message Box will appear in the middle of the screen with the Text of the Report (Figure 7). Reports are saved differently depending on the chosen form (to avoid overwriting), with the same name but different extension. The name is composed of: “IDnumber”_”Date”, For instance: 306724_20160226 (identification can be numerical or alphanumerical), date is composed as yyyymmdd. RTF rapports will have the extension *.rtf , in our example 306724_20160226.rtf PDF rapports will have the extension *.pdf , in our example 306724_20160226.pdf

DOC rapports will have the extension *.doc , in our example 306724_20160226.doc Export Text will have the extension *.txt , in our example 306724_20160226.txt Figure 7: Exporting report text

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Multilingual functions

Although all doctors are familiar with English, reports are usually written in the language of social communication. Presently, this program produces reports in English, Catalan, Spanish and French. Translation to other languages is foreseen in the near future (Portuguese, German) according to demand. The Setup (see point nr 1) allows selection of the main language every time the program is opened. The main language determines labels and texts for report presentation (numerical report, and text report) as well as the usual names of parameters. Text language of the automatic report can be changed at the time of execution through Menu “Report > Change Report Language” (to erase the present report, click Menu “File > Modify “, then [Accept], and do the report again “Report > General Report”): the numerical report will not be modified and the report appears in the selected language. You can also develop the report in two or more languages (Multilanguage report) simply by using Menu “Report > Change Report Language” and “Report > General Report”. The report in the new language will appear below, without erasing the previous one.

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Manual entry

Although seldom employed, manual entry of data is possible through the function “File > Manual entry”. Data can be entered manually and the automated interpretation and report form obtained. Predicted values are default values (ERS). A minimum amount of data is required:        

For demographics (mandatory): ID, Gender, Age, Height and Weight For Spirometry (optional): FVC and FEV1 For MFVC (optional): PEF, MEF50%FVC and MEF at the lower quarter of FVC (MEF25% or MEF75% depending on the local notation) For Volumes (optional): FRC, SVC and ERV (note: if SVC is omitted FVC is used instead to determine TLC!!) For Diffusion (optional): DLCO and VA For Arterial Blood Gases (optional): PaO2, PaCO2 and pH For Maximal Pressures (optional): PIM For Airway Resistance (optional): Raw and sGaw

Default data is current day data. When you click the [Continue] button, the Report will appear. You can save or print it as previously described. A figure can be added to the report, but does not appear on the screen. Consequently, figure shape function cannot be used. Manual entry is useful in case you have data obtained with a non connected device (useful for simple spirometry), for teaching purposes, to explore the program, etc.