Use of Endobronchial Ultrasound Scope (EBUS) Transducer to Identify Pneumothorax-A Feasibility Study

The use of ultrasound in diagnosis and treatment of patients has been well-established for
many decades. The use of thoracic ultrasonography is a fairly new and rapidly evolving field.
The interface between the ultrasound probe and chest wall can produce artifacts that can be
useful in diagnosing a pneumothorax. In one prospective study the utility of ultrasound was
compared to chest X-ray and CT-scan by trauma surgeon (1). Their results demonstrate that
ultrasound was more sensitive than chest X-ray to identify early pneumothorax. The study also
demonstrated that 63% of pneumothoraxes diagnosed were occult and would have been later
diagnosed on CT chest. In these critical situations where is subtle pneumothorax can be
missed, a bedside ultrasound has been proven to accelerate the diagnosis and thus treatment.
Similarly another prospective study noted that up to 76% of all traumatic pneumothoraxes were
missed by standard AP chest X-ray, when interpreted by trauma team (2). This number was
significantly higher than a retrospective study in which 55% of pneumothoraxes were missed on
AP chest films reviewed by radiologist (3). The sensitivity of ultrasound in detecting
pneumothorax has been demonstrated in multiple studies to be similar to CT-scan, which is
considered to be gold standard for the detection of pneumothorax (4, 5).

Visualization of normal pleural lung sliding is itself sufficient to exclude pneumothorax ,
if lung sliding is not present the finding of B lines( vertical lines), which usually
originate from the lung parenchyma will also exclude the possibility of pneumothorax at the
interspace in question, since the lung parenchyma cannot be visualized if there is air
interposed between the pleura and the lung.

Endobronchial ultrasound (EBUS) is considered an integral component of diagnosis of
indeterminate mediastinal lymph nodes, masses and peripheral pulmonary nodules. EBUS is
minimally invasive, safe and highly accurate (6). According to current estimates that
incidence if complications associated with EBUS is between 1-1.5% (6, 7). Major complications
are associated with needle aspirations. The incidence of pneumothorax was found to be 3.3% in
one retrospective analysis (8), with 31% of patients requiring chest tube eventually for
treatment of pneumothorax. Post-procedure chest-X-rays are commonly performed to rule out
pneumothorax. Based on current data chest-X-rays are considered suboptimal for diagnosis of
pneumothorax and can also expose patients to undue radiation.

The EBUS probe contains a small ultrasound through which ultrasound images of various
structure i.e. lymph nodes, ventricles, pulmonary vasculature can be visualized. Ruling out
pneumothorax via lung ultrasound using EBUS probe has never been described. If this is
possible, it avoids the need of obtaining post-procedure Chest-X-rays thus decreasing the
dose of radiation exposure and prevent time delays for the arrival of chest-x-rays.

In this study we will demonstrate the feasibility of using the transducer of the EBUS
Bronchoscope to perform bedside lung ultrasound to rule out pneumothorax.

Inclusion Criteria:

1. All patients presenting for bronchoscopy (These patient are expected to have normal
pleural sliding sign identified by ultrasound)

2. Patients with pneumothorax requiring chest tube(This group of patient is expected to
have residual pneumothorax for identification of absence of lung sliding, B lines and
lung point)

3. Patients with respiratory failure on mechanical ventilation(This group of patient is
expected to have alveolo-interstitial findings such as B lines)

Exclusion Criteria:

-Absence of informed consent