Pilot Study to Evaluate the Role of EBUS in the Diagnosis of Acute PE in Critically Ill Patients
Pilot Study to Evaluate the Role of EBUS in the Diagnosis of Acute PE in Critically Ill Patients
Acute pulmonary embolism (PE) in critically ill patients is common and often life
 threatening. The diagnosis of acute PE is often entertained in intensive care unit patients
 who develop unexplained hypotension or hypoxemia. Obtaining diagnostic confirmation of acute
 PE with a contrast-enhanced computed tomography of the chest (CT angiogram) may be difficult
 as patients are often too unstable for transport to the CT scanner or have renal
 insufficiency limiting the ability to receive intravenous contrast agents. Making or
 excluding the diagnosis of acute PE in these patients is critically important, as hemodynamic
 instability or right heart dysfunction, if due to PE, puts patients in the massive or
 submassive category and increased mortality risk. More aggressive therapies such as
 thrombolysis, extracorporeal membrane oxygenation or surgical embolectomy are often
 entertained. The investigators have previously described a case where endobronchial
 ultrasound (EBUS) was employed in the diagnostic algorithm of suspected acute PE and
 significantly affected treatment recommendations. The investigators believe that, in these
 patients, use of EBUS to assess for thrombotic occlusion of the central pulmonary vasculature
 can fill a critical gap in the decision tree for management of these patients.

 EBUS has become part of the diagnostic approach in a number of clinical situations, including
 the workup and staging of suspected malignancy, unexplained lymphadenopathy, and diagnosis of
 mediastinal and parabronchial masses. There is strong evidence that EBUS is equivalent to
 mediastinoscopy in the mediastinal staging of lung cancer. The number of physicians skilled
 and experienced in performance of EBUS has increased dramatically, and training in the
 procedure is frequently obtained in a pulmonary fellowship.

 To our knowledge, there have been no prospective studies that investigate the use of EBUS as
 a tool for the diagnosis of acute central pulmonary embolism in critically ill patients where
 obtaining diagnostic confirmation of this diagnosis with a contrast-enhanced computed
 tomography of the chest is not safe or feasible.
This is a single center, pilot study to evaluate critically ill patients diagnosed with acute
 pulmonary embolism using endobronchial ultrasound (EBUS). The investigators anticipate to
 enroll 20 subjects at Ronald Reagan UCLA Medical Center and UCLA Medical Center, Santa
 Monica. The enrolled subjects will be imaged using the flexible bronchoscopy with EBUS.

 After informed consent is obtained, the following procedure will be performed:

 An Olympus EBUS bronchoscope will be used for all endobronchial ultrasound examinations. This
 scope has a 6.9 mm outer diameter, a 2.7 mm working channel and 30-degree oblique
 forward-viewing optics. A 12 MHz linear ultrasound transducer with a maximum penetration of
 50 mm will be linked to a processor (Olympus EU-ME2) that allows an integrated power Doppler
 mode to visualize the vascular blood flow.

 Bronchoscopy will be introduced through the adaptor connected to the endotracheal tube, in
 patients who are already under general anesthesia and on mechanical ventilation. The
 bronchoscope will be advanced into the airways and endobronchial ultrasound of the main
 pulmonary artery (PA) and lobar branches will be performed in a standardized fashion as
 follow:

 Advance the bronchoscopy into the right main bronchus distally to the level of the right
 lower lobe, between 12 and 3 o'clock position where the interlobar artery of the PA is seen.
 Then the scope will be pulled back slowly, turning counterclockwise, following the course of
 the PA on the medial wall of the right bronchial tree until the level of the carina, where
 the right main PA and the PA trunk are seen. The scope is then turned to the right again,
 towards 3 o'clock following the right upper lobe bronchus to examine the upper lobar artery.
 The scope is then advanced into the left main bronchus, towards 9 o'clock to examine the
 upper lobar artery, then advanced distally to the left lower lobe bronchus to examine the
 interlobar artery. At the completion of the imaging the EBUS bronchoscope will be withdrawn.

 Ultrasound images and video will be stored to the machine and visualized thrombi will be
 marked.

 For patients who have had a chest CT for suspected PE, the investigators will assess
 sensitivity and specificity of EBUS to visualize or exclude PE. For patients who are unable
 to have a CT, the investigators will not be able to determine true efficacy, but will report
 the number of positive and negative studies and follow these patients for outcome and
 subsequent definitive diagnosis of venous thromboembolism.

 As this is a pilot study looking at the feasibility of EBUS for diagnosing acute pulmonary
 embolism, study personnel performing the EBUS will not be blinded to the clinical diagnosis
 and the management of the subject. A brief report of the procedure results will be uploaded
 in the patient's medical record. Any clinically relevant findings from the EBUS will be
 communicated to the subject's treating team. Regardless of the findings, a note stating that
 the EBUS technique is not yet established for evaluating acute pulmonary embolism in
 critically ill patients will be emphasized in order to prevent any bias in the patient's
 clinical care.

 Pulmonary Vascular Mapping Substudy:

 Of the 60 total subjects enrolled in the study, approximately 20 subjects under the criteria
 below will be enrolled at Ronald Reagan UCLA Medical Center and UCLA Medical Center, Santa
 Monica undergoing clinical bronchoscopy as a part of their standard of care. The enrolled
 subjects will be imaged using the flexible bronchoscopy with EBUS.

 Retrospective Chart Review:

 Of the 60 total subjects enrolled in the study, media including images and videos that are
 previously recorded for 20 patients who underwent a clinical bronchoscopy with EBUS as a part
 of their standard of care will also be available to our research team without consent from
 the patient to help supplement the data we obtain from the 20 subjects that are enrolled in
 the pulmonary vascular mapping substudy.
Inclusion Criteria:

 -  Patient ≥ 18 years of age.

 -  The patient or patient's surrogate must understand and sign informed consent form
 (ICF).

 -  Intubated patients in the intensive care unit (ICU) where there is a clinical concern
 for acute pulmonary embolism or a confirmed diagnosis for acute pulmonary embolism.

 Exclusion Criteria:

 -  Patient does not meet the requirements to undergo clinical bronchoscopy, as determined
 by the treating physician.

 -  Endotracheal tube size less than 8.0 mm.

 -  Contraindications to lidocaine.

 Pulmonary Vascular Mapping Substudy:

 Enrollment for the pulmonary vascular mapping substudy will be based on the following
 inclusion and exclusion criteria:

 Inclusion criteria:

 -  Patient ≥ 18 years of age.

 -  The patient or patient's surrogate must understand and sign informed consent form
 (ICF).

 -  Intubated patients undergoing clinical bronchoscopy, as determined by the treating
 physician.

 Exclusion criteria:

 -  Patient does not meet the requirements to undergo clinical bronchoscopy, as determined
 by the treating physician.

 -  Endotracheal tube size less than 8.0 mm.

 -  Contraindications to lidocaine.

 Retrospective Chart Review:

 Of the 60 total subjects enrolled in the study, media including images and videos that are
 previously recorded for 20 patients who underwent a clinical bronchoscopy with EBUS as a
 part of their standard of care will also be available to our research team without consent
 from the patient to help supplement the data we obtain from the 20 subjects that are
 enrolled in the pulmonary vascular mapping substudy.