Objective: To investigate the differences of the locations and signs of the phrenic points between the Modified Bedside Lung Ultrasound Examination (M-BLUE) and Bedside Lung Ultrasound Examination (BLUE).
Methods: A total of 61 consecutive patients who were treated in the Department of Critical Care Medicine at Peking Union Medical College Hospital in January and February of 2015 were enrolled in this study. BLUE and M-BLUE were both performed on each patient. The differences of examination results were compared.
Results: (1) There were 47.5% (58/122) different locations of the phrenic points and 18.0% (22/122) different echo-signs between the BLUE protocol and the M-BLUE protocol. (2) Compared with BLUE protocol, changes of locations [67.9% (19/28) vs 33.3% (11/33)] and signs [42.9% (12/28) vs 12.1% (4/33)] of the phrenic points in the M-BLUE protocol in patients with respiratory failure were significantly higher than those without pulmonary diseases. Among 5 patients with acute respiratory distress syndrome and 6 patients with chronic obstructive pulmonary disease, all presented changes in locations of the phrenic point in the M-BLUE protocol, while 3 and 4 showed changes in signs respectively. (3) Signs of the phrenic point in the M-BLUE protocol were more consistent with the result of the chest CT than those in the BLUE protocol.
Conclusion: Compared with BLUE protocol, M-BLUE protocol seems more accurate in locating the phrenic point and more specific for the diagnosis of pulmonary disease. Compared with BLUE protocol, M-BLUE is more valuable for critical patients.