ABSTRACT
Objective:To evaluate the clinical effectiveness and safety of a respiratory training device (patent No.201320672057.6), which was developed and produced in China.Methods:Sixty patients with chronic respiratory diseases admitted in China-Japan Friendship Hospital from May 2019 to July 2019 were enrolled in the study. Patients were randomly divided into trial group ( n=30) and control group ( n=30), in the trial group, respiratory training device was used on the basis of conventional treatment, while in the control group, patients received conventional treatment only. Baseline data were collected at the time of enrollment, patients were followed up every 4 weeks, and the final data were collected at the 16th week. The primary outcomes were mMRC score, LCQ score and expectoration. The secondary outcomes were pulmonary function, respiratory muscle strength, SpO 2, FeNO, SGRQ score, times of acute exacerbation and adverse events. Results:There was no significant difference in proportion of decreased mMRC score between trial group and control group [36.0% (9/25) vs. 23.1% (6/26), Z=-1.044, P=0.301). On expectoration, the decrease rate of no-sputum patients in the trial group was significantly higher than that in the control group [28.0%(7/25) vs. 7.7%(2/26), Z=2.050, P=0.041]. In addition, 56%(14/25) patients in the trial group had a decrease in sputum volume compared to 19.2%(5/26)in the control group ( Z=-2.574, P=0.010). There was no statistical difference between the two groups before and after the follow-up in LCQ score( F=0.668, P=0.418). The PEF of pulmonary function in the trial group was significantly improved compared to the baseline( F=4.532, P=0.039); and R 35 was also significantly improved in the trial group( F=4.125, P=0.048). In terms of quality of life, the study found no statistical differences in SGRQ scores between baseline and follow-up. However, the SGRQ symptom score decreased significantly in trial group( F=7.481, P=0.009). There was no statistical difference in acute exacerbation between the two groups ( Z=0.297, P=0.766). No adverse events occurred during the follow-up period. Conclusions:This study evaluated the clinical effectiveness and safety of a respiratory training device developed in China. In terms of the clinical effectiveness, the device can reduce sputum, increase PEF, reduce R 35, indicating that there is a certain therapeutic effect. It is not clear that the device can reduce the severity of dyspnea and pulmonary function, improve quality of life, reduce the times of acute exacerbation. In terms of safety, the device did not show adverse effects during follow-up in this study.
ABSTRACT
A novel linear polarization converter operating in C- and X-bands with high polarization conversion ratio is described and demonstrated based on frequency selective surface. The building element is a planar-dipole pair, which is orthogonally printed on a double-layer substrate and vertically connected by a pair of through-via holes functioning as a quasi-two-wire transmission line coupler. A perforated metal shielding layer is sandwiched between the double-layer structure to only support a transverse electric and magnetic (TEM) mode coupling between the top and bottom dipolar components. The front dipole responds to the incident transverse electric (TE) wave, and sends the induced current into the two-wire transmission line to feed the bottom dipole. The bottom dipole is orthogonal or oriented at an arbitrary angle with respect to the top one, and a resultant outgoing transverse magnetic (TM) wave or arbitrary orientation polarized wave can be achieved. In addition, a bidirectional orthogonal polarization converter is realized by using double orthogonally arranged planar-dipole pairs, which are also printed on the same double-layer substrate.
