ONKOCET Ltd. has exhibited the devices from its portfolio on the MEDTEC UK exhibition in Birmingham, April 2011 through our partner Medical & Partners.
In accordance with in force standard on the spirometry, the developed together American thoracic society and the European respiratory society (ATS/ERS 2005), the results of spirometric study will be diagnostically meant with satisfaction of the following basic conditions:
Fig. 1. Protocol of a study with the first attempt.
Fig. 2. Protocol of a study with the second attempt.
Fig. 3. Protocol of a study with the fourth attempt.
Fig. 4. Protocol of a study with the fifth attempt.
Based on the example of conducting the study of FER, executed with the patient N, we will illustrate the importance of satisfaction of the conditions mentioned above.
The first protocol of the study, carried out on the spirometer MAS-1, is represented in figure 1.
Let us note that the spirometer MAS-1 in accordance with ATS/ERS 2005 it measures and calculates besides the parameters of FER the following parameters of the technical acceptability of the tests:
and also the parameters of reproducibility of the tests:
Furthermore, instrument informs about a quantity of attempts, executed in the maneuvers VC (Nspiro) and FVC (Npneumo).
Thus, the purpose of conducting a spirometric study is reaching the diagnostically significant and reproducible studies of FER, about than the instrument informs by sign “+” in the appropriate criterion of the quality of tests. As is evident in figure 1, the first protocol of the study FER informs about a reliable study in the spirometry Nspiro “+” (3 attempts), dVC “+” and about the fulfillment of one (Npneumo = 1, “-”) technically acceptable attempt in the maneuver FVC (Vextr = 0,04 l, “+”, VfinPn = 0,08 l, “+”). The conclusion of instrument “moderate disturbances according to the mixed type” - are reduced both the volumetric (VC, FVC) and high-speed (FEV1, MEF 50, MEF 75, FEF 25-75) indices of pulmonary ventilation. Let us note that the patient carried out spirometry for the first time.
With conducting of the second attempt (Fig. 2) we see the already more adequate performance of maneuver FVC: FEV1 grew from 1,97 l to 2,38 l - patient, being trained, made more energetic expiration. Problematic are early curtailment of expiration (duration of expiration ~ 1,2 s, VfinPn = 1,07 l, “-”), and also insufficient reproducibility FEV1 (0,41 l, “-”). Therefore should be carried out still one attempt in the test FVC.
Let us note that the more energetic accomplishment of maneuver FVC led to the normalization of high-speed indices FER (corresponding columns in the diagram they were shaded), and conclusion fixes only the “initial manifestation of disturbances according to the restrictive type”. Finally, in the 4th (Fig. 3) to technically acceptable attempt (Vextr = 0,02 l, “+”, VfinPn = 0,09 l, “+”) we obtain required reproducibility FEV1 (dFEV1 = 0,07 l, “+”), and FVC grows from 2,40 l to 2,66 l and composes 87% with respect to the proper it, i.e., corresponds to standard.
In the 5th attempt (Fig. 4) is reached reproducibility FVC (dFVC = 0,08 l, “+”), that can be treated as the correct completion of test FVC. Conclusion of the spirometer: “the ventilation function of lungs is not disrupted”.
Thus:
Thus, if we carried out only one attempt in the pneumo-tachometry, and often then it occurs in the practice of functional diagnostics, then in the patient would be “moderate disturbances according to the mixed type”. The following (2nd) attempt with the more energetic expiration leads to the removal of obstruction, and in the patient of altogether only the “initial manifestation of disturbances according to the restrictive type”.
Finally, the 4th attempt with the technically acceptable (more complete) completion of expiration (VfinPn = 0,09 l, “+”) makes it possible to remove initial restriction, giving the conclusion: “the ventilation function of lungs is not disrupted”.
It should be noted that in patients, who regularly carry out spirometry, such spreads of respiratory maneuvers they are encountered more rarely; however, in this case the expert system of spirometer MAS-1, which calculates the criteria of technical acceptability and reproducibility of tests, it makes it possible completely to clearly divide the objective spirometry (maximum quantity “+” in the criteria of the quality of tests), which gives the diagnostically significant results, from the spirometry, executed not in accordance with the standards (significant quantity “-” in the criteria of the quality of tests). Last situation can appear with conducting of studies by insufficiently experienced personnel, and also with the examination of the ability to work/of the disablement, when it is necessary to objectively prove the cases of possible simulation that also makes it possible to make protocol of the study FER of the spirometer MAS-1 on the basis of the criteria values of quality tests.
When the protocol of a study does not contain information about quality and completeness of the carried out tests, to doctor, who interprets spirogram, to there remains only hope for honesty and competence of the medical staff (its clinic or any other, from where it was directed patient), which conducted the study of FER.