Pleural effusions are common and ultrasound can find them. Point of care ultrasound may assist in diagnosing pleural effusion as the cause of a patient’s symptoms. The “extension of the thoracic spine” sign is an ultrasound sign that can identify pleural effusions not otherwise evident on ultrasound.
How sensitive and specific is the “spine sign”?
Inclusion: >18 yo + getting CT of abdomen or chest as part of work up (symptoms or chief complaint did not matter)
Exclusion: if consent could not be obtained, could not tolerate 45 degrees back, known pleural effusions, lung surgery, pleurodesis
3 emergency physicians - all had extensive experience with point-of-care sonography (2 had completed fellowship) who were not caring for the patient
Attended a lecture regarding how to diagnose pleural effusions with ultrasound
Single urban, academic, tertiary care center
Prospective convenience sample of ED patients, only enrolled when sonologist present
Calculated sensitivity and specificity
All patient enrolled received ultrasound and their CT.
Patient supine, head elevated 45 degrees. Left and right lung bases in mid axillary line, looked for anechoic fluid collection and/or “spine sign”.
Spine sign = extension of the normally seen vertebral bodies superior to the diaphragm
N = 41 patients = 82 hemithoraces
7 excluded (no images obtained)
Median time to complete scan: 3 minutes (max 13 minutes)
25% of population had pleural effusion on CT: 2 large, 12 small, 5 trace
Primary end point: Sensitivity 73.7%, Specificity 92.9%
If using spine sign + anechoic fluid: Sensitivity 78.9%, Specificity 87.5%
If exclude trace effusions: Sensitivity 92.9%, Specificity 92.9%
Broad inclusion criteria
Excluded patients in which we would like to know its accuracy (hx of pleural effusion, thoracic surgery, etc)
Small sample size, single center
Performed by skilled operators
1. Thoracic spine sign alone is about 74% sensitive and 93% specific.
2. With regard to non-trace pleural effusions, thoracic spine sign is 93% sensitive and specific.