Evaluate the Utility of Lung Ultrasound as a Diagnostic Tool in Patients With Acute Respiratory Failure.

Abstract

OBJECTIVES To evaluate the utility of the lung ultrasound using the BLUE protocol as a diagnostic tool and analyze all clinical,investigational data of patients and compare the provisional diagnosis made using the lung ultrasound with the final diagnosis.METHODS An observational study to evaluate the utility of lung ultrasound using the BLUE protocol as a diagnostic tool in patients with acute respiratory failure admitted to our Respiratory Intensive Care Unit during a period of August 2014 to December 2015 where 100 patients were included in the study.Three items were assessed:lung sliding, artifacts (horizontal A lines or vertical B lines indicating interstitial syndrome), alveolar consolidation, and / or pleural effusion.Venous scan to screen for deep venous thrombosis was done wherever required.Ultrasound equipment used was GE-LOGIQe.It has both the convex and the ECHO probes.The diagnosis obtained by the thoracic ultrasonography with limited echocardiography was compared with clinical diagnosis arrived by the ICU team at the end of the hospital stay.RESULTSThe mean age of the patients was 65.1±15.08 years.While the mean age in our study was almost similar to that seen in the BLUE protocol (68 years),the difference seen in gender distribution was owed mainly to the large sample size of the previous studies.In our study, Pneumonia was observed in 34% patients with A profile plus PLAPS being the most common finding followed by B' profile and A/B profile.Exacerbations due to COPD/Asthma/ILD accounted for 32% of the total patients in our study with A profile without PLAPS being the commonest pattern on lung ultrasound in patients of COPD/Asthma followed by B profile in patients of ILD. Lung ultrasound does not diagnose COPD/Asthma exacerbations, but rather by ruling out other causes of acute respiratory failure it arrives at the possible diagnosis of COPD/Asthma exacerbations. Pulmonary odema was observed in 23% of patients with B profile without PLAPS being the commonest finding.9% patients had pneumothorax and A' profile with a posterolateral lung point was present in all the cases.Absence of sliding is not specific as it can be present in other conditions also.The presence of lung point is a very specific finding for the diagnosis of pneumothorax. Both the patients of Pulmonary embolism had A profile with deep vein thrombosis on venous scan.Regardless of the initial profile (A or B),the lower limb Doppler ultrasonography should be done. CONCLUSION Majority of our patients presenting with acute respiratory failure in the RICU were males,mostly elderly,in the age group of 60 years and above with significant comorbidities.Our study has demonstrated the excellent diagnostic yield of lung ultrasound using the BLUE protocol as a diagnostic tool for the evaluation of patients with acute respiratory failure.The results obtained in our study were similar and comparable with the studies done in developed countries and this modality can be used with ease and confidence in the evaluation of acute respiratory failure in the Indian settings by non radiologists ICU physicians