PURPOSE: Differences in lung sound amplitude according to lung condition have been reported in patients with different chest radiographic densities (CXR)1. The objective of this study was to validate these findings in mechanically ventilated cancer patients.
METHODS: Lung sound measurements were obtained from seventeen mechanically ventilated cancer patients (eleven males, six females, age 59±14) using the Vibration Response Imaging (VRI) monitoring system. Two arrays of 17 piezoelectric sensors positioned posteriorly were used to assess mean sound amplitude at peak inspiration. Lung sound assessments were correlated with findings in CXR. P-values (Mann Whitney U Test) are reported.
RESULTS: Patients were classified in two groups according to their primary CXR finding, namely consolidations (n=11) and pleural effusion or atelectasis (n=6). Significantly increased mean sound amplitude was registered in patients with consolidation when compared to patients with pleural effusion or atelectasis (p=0.01). When using the suggested threshold for differentiation between consolidation/congestion and other CXR findings (~20.106 Arb. Units), the positive predictive value (PPV) was 91% (10/11). The false positive observation was derived from a patient with pigtail catheter in place at the time of the measurement.
CONCLUSION: Sound amplitude can be useful in the differentiation between consolidations and other radiographic densities in mechanically ventilated cancer patients. Interference of chest drainage therapy during sound amplitude measurement should be taken into consideration.
CLINICAL IMPLICATIONS: VRI could be a useful non-invasive diagnostic tool for clinicians trying to differentiate lung infiltrates and a potential early detector for new lung pathologies. Reference:1. Lev S, Glickman YA, Kagan I, Shapiro M, Moreh-Rahav O, Dahan D, Cohen J, Grinev M, Singer P: Computerized Lung Acoustic Monitoring Can Help to Differentiate between Various Chest Radiographic Densities in Critically Ill Patients. Respiration 2010; Epub Jan 7.
DISCLOSURE: Joseph Nates, No Financial Disclosure Information; Product/procedure/technique that is considered research and is NOT yet approved for any purpose. I do not have any finacial relationship with the company that produces the tool/monitoring device I will discuss in the meeting