PT  - JOURNAL ARTICLE
AU  - Surussawadi Bennett
AU  - Michael Bennett
AU  - Tom Havelock
AU  - Anna Barney
AU  - Peter Howarth
AU  - Anne Bruton
TI  - LATE-BREAKING ABSTRACT: The relationship between crackle characteristics and regional ventilation/perfusion ratio measured by SPECT/CT
AID  - 10.1183/13993003.congress-2015.PA3738
DP  - 2015 Sep 01
TA  - European Respiratory Journal
PG  - PA3738
VI  - 46
IP  - suppl 59
4099  - http://erj.ersjournals.com/content/46/suppl_59/PA3738.short
4100  - http://erj.ersjournals.com/content/46/suppl_59/PA3738.full
SO  - Eur Respir J2015 Sep 01; 46
AB  - Crackle lung sounds are believed to be generated by the reopening of abnormally closed airways which are found in many cardiopulmonary diseases. The mismatch of ventilation (V) and perfusion (Q) in the lung, as measured by the V/Q ratio, can represent the impairment of gas exchange under the condition of abnormal airway closure. The objective of this study was to explore any relationship between the characteristics of crackles measured by Computer Aided Lung Sound Analysis (CALSA) and regional V/Q ratio measured by Single Photon Emission Computed Tomography (SPECT), and hence the possibility of using crackles to indicate impaired gas exchange in the lungs. Twenty-four participants (7 COPD, 8 healthy smokers and 9 healthy non-smokers) were examined with simultaneous SPECT/CT ventilation and perfusion scans (GE Systems, Milwaukee, WI, USA). Lung sounds were recorded using a digital stethoscope (ThinkLabs ds32a, USA) connected to a laptop computer. The results showed that, after a Bonferroni correction, there was a significant correlation between crackle 2CD and V/Q ratio for both left lower lobe (LLL) (r=0.63, p=0.001) and right lower lobe (RLL) (r=0.68, p=0.0002).Additionally, the crackle 2CD at LLL and RLL were found to significantly predict the V/Q ratio at the LLL and RLL (adjusted R2=0.39 and 0.44, R2=0.37 and 0.47 respectively, p=0.001). These initial results indicate that crackle 2CD might be able to predict the mismatch of V/Q caused by many pulmonary diseases, though a larger sample is needed to confirm it. This suggests that crackles could be used as an indicator of impairment of gas exchange.