Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01535248 |
| Other study ID # |
0238-11-FB |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
March 7, 2012 |
| Est. completion date |
December 30, 2015 |
Study information
| Verified date |
August 2023 |
| Source |
University of Nebraska |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopy technique to visualize
and evaluate the pancreatic and biliary systems. It has been reported that rare instances of
air embolus have been found associated with the performance of an ERCP and many of these
events are fatal. It is our proposal to use transthoracic echocardiography to continuously
evaluate for the presence of intra-cardiac air secondary to ERCP venous air embolism and
attempt to quantify the incidence of this complication and any potential patient factors that
might increase the risk of this complication.
Description:
Endoscopic Retrograde Cholangiopancreatography (ERCP) is commonly used in the diagnosis and
treatment of biliary and pancreatic disease. There are case reports presented in the
literature demonstrating adverse and often fatal events following air embolization associated
with the performance of ERCP. The frequency of air embolus is extremely rare with the exact
incidence unknown. In recent years the utilization of echocardiography to evaluate
individuals with hemodynamic instability has led to the discovery of intracardiac air embolus
seen in those individuals that demonstrated changes in either hemodynamic parameters or
capnography values. There exists proposed mechanisms for the translocation of air from the
foregut to the systemic venous circulation but not one of these mechanisms has yet been
validated. Some proposed mechanisms include either through intrahepatic mechanisms where air
crosses from the biliary tract to hepatic venules or potentially from the foregut into the
portal vein and through shunt vessels into systemic venous circulation.
The exact frequency of air embolus is likely higher than the incidence of fatal or near-fatal
complications reported in the literature. Individuals that had the best outcomes were usually
intubated and had capnography to demonstrate a change suggestive of air embolus prior to
significant hemodynamic changes.1 As this phenomenon has not previously been well described,
it is possible that other patients suffer significant air embolus with myocardial or cerebral
ischemic sequelae that were not recognized because echocardiography was not used as an early
tool for evaluation of hemodynamically unstable patients. It is also possible that there are
a number of patients that may suffer a venous air embolus from ERCP that is sub-clinical and
therefore not causing enough change in cardiac function to alter either hemodynamic
parameters or capnography values. The literature suggests that if a patient does not awake
following ERCP, that imaging modalities, such as echocardiography be employed for
evaluation.1 Understanding the frequency of this problem or which subgroups are at risk can
further aid in the diagnosis and treatment of this complication.
Transthoracic echocardiography is a highly sensitive imaging modality and if adequate imaging
windows can be obtained will demonstrate the presence of intracardiac air. The risk of
performing the study on the patient is zero to very low. The potential risk of inaccurate
interpretation should be avoided by the use of trained individuals in the acquisition and
interpretation of transthoracic echocardiographic images.
The purpose of this study is to 1) identify individuals scheduled to undergo elective ERCP as
part of their plan-of-care and perform transthoracic echocardiography for surveillance of
intracardiac air embolus 2) record aspects of their past medical history that may potentially
contribute to increased risk of systemic venous air embolus. This evaluation has not been
presented in the literature and the primary end-point of this study would be to determine the
frequency at which venous air embolus associated with ERCP occurs.
All individuals that meet inclusion criteria will be approached and consented in the
pre-operative area prior to the planned procedure (ERCP). Their past medical history will be
reviewed with the patient and special attention placed on particular co-morbid conditions
that might be related to this phenomenon including but not limited to: portal hypertension,
cirrhosis, portal vein thrombosis, and recent liver biopsy. The patient will then proceed to
the procedure room as planned and while the patient is placed in the left lateral decubitus
position and induced under anesthesia. An echocardiography-trained anesthesiologist will
perform a transthoracic echocardiogram (TTE) concurrently while the gastroenterologist is
performing the ERCP. We plan on conducting serial images at least every ten to fifteen
minutes throughout the ERCP and more often as needed. At the conclusion of the procedure
(ERCP) if there are no significant findings on TTE the patient will be returned to the supine
position and taken to the recovery room. The written record of the TTE will then be entered
into the study database within a separate research chart. In the event that the TTE shows the
presence of intracardiac air embolus during the procedure the member of the study group
performing the TTE will notify the endoscopist and anesthesia provider of the findings if the
findings are significant enough to require a change in the patient's medical care. Reference
to the algorithm will be made in each case and be available online if needed. Unless a
moderate to severe embolic event occurs, the findings will not be communicated to the
gastroenterologist so that he is blinded to the result maintained in the research chart. The
purpose of this is to keep clinically insignificant emboli from being reported in the
patient's medical record.
One of the key components of this evaluation is determining whether the presence of an air
embolus has occurred and if so, has it had a negative effect on the function of the subject's
cardiovascular system. Our proposed evaluation of the myocardium using transthoracic
echocardiography includes evaluation of the left ventricle, right ventricle and pulmonary
artery pressures. In the event there is hemodynamic instability as a result of impaired
function of the right or left ventricle, an evaluation including measurements of the
following parameters will assist in determination of the problem:
1. Right ventricular function, specifically tricuspid annular plane systolic excursion
(TAPSE and the presence of hemodynamic changes.
2. Left ventricular function, specifically diastolic function, systolic function and
myocardial performance index.
3. Pulmonary artery systolic pressure, via evaluation of the tricuspid regurgitant jet
maximum velocity using the modified Bernoulli equation.
4. Presence of a new right-to-left intracardiac shunt or bowing of the intraatrial septum
from right-to-left indicating a new increase in the right atrial pressure.
5. Significant changes in hemodynamic status that would indicate that the subject does not
have effective filling and ejection of the left ventricle to support a perfusing blood
pressure. This may manifest as hypotension and/or tachyarrhythmias on standard
intraoperative monitoring.
As this protocol evaluates the frequency and degree of air embolization into the systemic
venous system during the performance of endoscopic retrograde cholangiopancreatography
(ERCP), the following four subgroups have been identified to help define the identification
and treatment of subjects enrolled into IRB 238-11. Each category has a) criteria for the
visual quantification of the air seen and b) the cardiac function and hemodynamic changes
seen and finally c) the planned intervention if needed:
1. No air embolism:
1. No visualized air emboli during the procedure.
2. Subjects have no hemodynamic or myocardial changes attributable to the occurrence
of venous air embolus.
3. No changes would be made to the standard care of this research subject as a result
of the absence of findings. Findings will be entered into the research chart.
2. Small air embolism:
1. A small, but identifiable quantity of air visualized that does not form a large
collection and does not obscure visualization of the far-field.
2. Subjects have no changes in myocardial function and maintenance of hemodynamics.
3. The subject would then undergo follow-up evaluation by a member of the study group
at the conclusion of their normal post-op recovery period. No additional time would
be required for evaluation and documentation of hemodynamic stability and follow-up
echocardiography findings would be recorded in the research chart.
3. Moderate air embolism :
1. Identifiable intracardiac air within the heart that obscures the far-field due to
its size but does not cause a sharp demarcation at the blood/gas interface.
2. Subjects have documented impairment of myocardial function and/or hemodynamics
compared to baseline but do not require emergency resuscitation to correct.
3. The subject would remain in the left lateral decubitus ("safe position" for
individuals with suspected or confirmed venous air embolism) for four hours.
Laboratory tests including cardiac enzymes may be obtained and a member of the
study team will re-evaluate with transthoracic echocardiography. If baseline
function and hemodynamics return, the subject concludes their recovery period as
per normal circumstance for ERCP. In the event the subject has persistent
intracardiac air, impaired myocardial function or hemodynamic instability, it would
be recommended that the subject stay for observation with telemetry monitoring and
further evaluation as needed.
4. Large air embolism:
1. Identifiable intracardiac air which collects into a large enough bubble to cause
sharp demarcation at the blood/gas interface and obscures the far-field.
2. Left and/or right ventricular failure with hemodynamic collapse.
3. The subject would require emergency resuscitation and ACLS protocol in addition to
placement of invasive monitors for evaluation. Attempts to extract intracardiac air
using central venous catheter will be made and as needed intubation with transfer
to the ICU for further monitoring. Consultation for hyperbaric oxygen therapy would
be pursued and all measures would be taken to recover hemodynamic function.
