Transthoracic ultrasound for pleural effusion: traps and tricks

Abstract

SummaryPleural effusion is excess fluid that accumulates between the two pleural layers. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation. Pleural effusion is still usually diagnosed on the basis of medical history and physical examination, and confirmed by chest x-ray. It is observed in many pulmonary and extra-pulmonary disease; its cause can be relatively benign or definitely malign (cancer), and may require drainage for treatment or for achieving a diagnosis which is available at the bedside by physical examination and Thoracic Ultrasound (TUS). Pleural effusion is detected by TUS even when its volume is very little: it is possible to perform and repeat at bedside, by sufficiently trained physicians. Diagnostic intervention procedures are safer if performed using US probes specifically designed for this use, i.e. with a central hole which allows the co-axial passage of the disposable tools for drainage or Fine Needle Aspiration Biopsy (FNAB). Over-trusting in US criteria not evidence-based and, more important, which are demonstrated to be unreliable when critically re-appraised must be discouraged; reversal of such scarcely validated but recommended practices, which could be harmful for patients, is actively in progress also in this field of medicine. No special trick is needed and no actual trap is present when the assessment of pleural effusion is performed by a sufficiently skilled MD and with a reliable and well set echo machine. Echo-assisted thoracentesis is an excellent procedure when appropriately performed in all its phases, which are: choice of the site of insertion, visualization in real-time during the drainage and serial control during lung re-expansion (so as to avoid pneumothorax). KEY WORDS: ultrasound, pleural effusion. Transthoracic ultrasound: overviewThe ultrasound examination in the study of pleuro-pulmonary disease, i.e. Thoracic Ultra-Sound (TUS), is limited by the presence of air in the lungs and by the rib cage (1). As a consequence TUS is not an all purpose tool, drawbacks and appropriate indications must be the cynosure of the pneumologist which relies on TUS for diagnosis and management of patients (2). The presence of the bony structures of the rib cage restricts the success of ultrasound imaging of the pleural surface to about 70% of the total (3). These issues, relating to limitations on the use of ultrasound in the thoracic area, have been known since the ʼ60s, a time when pioneering works were published using A-mode for exploring pleuro-pulmonary structures and, namely, pleural effusion (4), even in comparison with radiological imaging and with a greater sensitivity and specificity (5). Thereafter these advantages were established in the few subsequent years, with minimal further refinements despite the technology of ultrasound equipment has evolved considerably (6, 7): the value of ultrasound examination of the pleura and lungs remains highly underestimated to this day, and overstatements (8) and over- Mini-review...

A Transthoracic Ultrasound-Guided Needle Biopsy Provided the Diagnosis for a Synovial Sarcoma of the Pleura

“…4 The US appearance may also suggest the probable nature of the effusion, guiding in advance the choice of the needle’s caliber to be used for thoracentesis: For example, a transudate (i.e., generally an anechoic effusion) will require a 20-gauge needle, whereas a corpusculate effusion (i.e., a septated or homogeneously echogenic effusion) will require the use of a larger 18-gauge needle. 13 Considering that US does not imply exposure to ionizing radiation and is easily performed at patient’s bedside, it should be the preferred approach in the presence of adequate skills.…”

Role of pleural transthoracic ultrasound guidance

“…We have performed 3870 drainages in the last 10 year with TUS guidance. [ 2 ] A diagnosis of malignant effusion was done in 630 patients (18%) with cytology on fluid samples. The rate of major complications was low: only four patients (0.1%) had iatrogenic pneumothorax (three showed partial pneumothorax and one subtotal pneumothorax; with full lung reexpansion in each case), and two patients had reexpansion lung edema.…”

“…The rate of major complications was low: only four patients (0.1%) had iatrogenic pneumothorax (three showed partial pneumothorax and one subtotal pneumothorax; with full lung reexpansion in each case), and two patients had reexpansion lung edema. [ 2 ]…”