A study of the use of Forced oscillation technique in the evaluation of COPD patients: Analysis of different parameters and utility compared with spirometry

Dr. Anita Agrawal; Dr. Chetan Rajput; Dr. D. N. Shenvi

Volume : VII, Issue : XII, December - 2017

A study of the use of Forced oscillation technique in the evaluation of COPD patients: Analysis of different parameters and utility compared with spirometry

Dr. Anita Agrawal, Dr. Chetan Rajput, Dr. D. N. Shenvi

Abstract :

The ability to objectively measure lung function in COPD patients is critical in the assessment and treatment of COPD. We thus determined the effectiveness of Forced Oscillation Technique (FOT) as a non–invasive technique to assess lung function in COPD patients and in comparison to spirometry for sensitivity and specificity, testing variability, and the order effect of sequential testing of FOT and spirometry.

Methods

Forty COPD patients (mild, moderate, severe) from PFT Lab of Chest Medicine Department of KEM Hospital, Mumbai and 40 normal healthy individuals (volunteered controls) from various departments of Seth G. S. Medical College, Parel, Mumbai were evaluated in a clinic and under medical care for disease, were asked to perform FOT and spirometry. The utility of FOT and spirometry in differentiating patients that had COPD versus those adults who did not was then analyzed.

Results

The mean age of COPD and control group was 54.1 ± 14.54 years and 53.38 ± 13.25 years respectively. Each group was comprised of 40 patients. Average age of both groups was comparable. (p=0.8163)

Mean FEV1 (%) of COPD and Control group was 55.29 ± 19.42 and 92.11 ± 11.17 respectively. There was significant difference of mean FEV1 values between both the study groups. (p=<0.0001)

Mean FEV1/FVC of COPD and Control group was 58.00 ± 9.86 and 81.81 ± 4.20 respectively. Average FEV1/FVC was significantly higher in control group than COPD. (p=<0.0001

Mean FOT of COPD and Control group was 199.93 ± 75.01and 70.75 ± 44.41respectively. Average FOT was significantly higher in COPD than control group. (p=<0.0001)

Since the AUC value is 0.97, the test has an excellent diagnostic use. The p value is 0.000 (<0.05), so the result is significant. The diagnostic method is intended for use as a diagnostic tool and not as a screening technique. Therefore higher specificity was desired as compared to sensitivity. By analyzing all the values of coordinates, the cut off value of FOT of 126.5 gives sensitivity of 90.0 % and specificity of 97.5%.

Conclusion

In the diagnosis and management of adults with COPD, FOT is a non–invasive approach that easily and objectively measures lung impedance and should be considered as both an adjunct, and in some situations, an alternative to standard spirometry.