Single breath counting : a simple alternative to pulmonary function assessment /
Madelynn B. Cantor-Quimson
OBJECTIVE: To assess Single Breath Counting (SBC) as an alternative to spirometry (Pulmonary Function Testing, PFT) and establish values to detect the normal from those with lung disease and find out if it can classify the degree of pulmonary obstruction among the patients
STUDY DESIGN: Prospective comparison of PFT and SBC using within subjects strategy
SETTING: Outpatient Chest Clinic of Veterans Memorial Hospital, Quezon City
SUBJECTS: Forty-two evaluable patients who consulted the clinic from July 9 to October 9, 1997 were randomly chosen and have satisfied the inclusion criteria
MAIN OUTCOME MEASURES: Single Breath Counting was compared to Pulmonary Function Testing using the Spirosense Spirometer and the FEV1, FVC, FEV1/FVC ratio and FEF and PEF predicted values computed and the results analyzed using the Pearsonr Correlation and Regression Analysis; and the sensitivity and specificity of SC evaluated; and a One-way ANOVA computed to analyze correlation of SBC values to degree of pulmonary obstruction
RESULTS: An SBC value of more than 23 seconds distinguished the normal cases from those with pulmonary impairment. SBC has a specificity of 85.71% superior to that of PFT with 76.47% but lesser sensitivity in identifying patients with obstructive pulmonary disease (SBC, 71.43% against PFT, 78.26%). SBC values in different degrees of obstruction yielded: mild = -19-23 seconds, moderate = 14-18 seconds and severe - 14 seconds when compared to FEV1 percent predicted values and when compared to FEV1/FVC ratio percent predicted values, the SBC for mild
CONCLUSIONS: Single Breath Counting may be a guide for further pulmonary testing or may even be a simple alternative to standard Pulmonary Function Test yielding comparable results in detecting patients who are normal and those with pulmonary obstruction with good specificity and sensitivity.
The Filipino Family Physician, 1998 36 (2) pages 39-44