An Evaluation of the Utility of the ExSpiron Respiratory Variation Monitor During Upper GI Endoscopy



Status:Recruiting
Conditions:Cancer, Cancer, Gastrointestinal, Gastrointestinal
Therapuetic Areas:Gastroenterology, Oncology
Healthy:No
Age Range:21 - Any
Updated:10/14/2017
Start Date:September 2014
End Date:December 2016
Contact:Alexander Friend, M.S.
Email:alexander.friend@vtmednet.org
Phone:802-847-4259

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Purpose: To assess the utility of a new medical device that monitors a patient's breathing
during medical procedures in which a patient is sedated, but not mechanically ventilated. In
minor procedures, such as endoscopy (where the doctor examines a patient's digestive tract by
a TV camera inserted through the mouth), patients do not require general anesthesia, in which
a machine would take over their breathing while they are unconscious for surgery. However,
during endoscopic procedures it is sometimes difficult for the anesthesiologist to monitor
the patient's breathing—specifically, to monitor changes in breathing patterns and the
adequacy of breathing. In endoscopy procedures, the room is darkened, and the patient's mouth
is generally occupied by the endoscope. While the anesthesiologist can listen to the
patient's breathing sounds with a stethoscope, this type of monitoring can only be done
periodically, and there is limited ability to gauge the adequacy of ventilation. This study
will use the ExSpiron Respiratory Volume Monitor (RVM), which measures non-invasive minute
ventilation (MV), tidal volume (TV) and respiratory rate (RR), in patients undergoing an
endoscopic procedure to provide additional information regarding the effects of clinical
interventions such as drug administrations or airway maneuvers on the patient's respiratory
status.

For patients who give informed consent, study participation means that they will have a
PadSet consisting of 3 electrodes applied to the chest. Another component, a nasal cannula (a
thin clear plastic tube that goes under the nose) will give patients supplemental oxygen, and
is standard of care for endoscopy at UVM Medical Center. Patients will then be asked to
breathe in and out of a portable spirometer (breath meter) for 30 seconds up to five times.
This data will be compared to data recorded by the monitor to confirm that the monitor is
recording accurately. The procedure will then go forward in the normal fashion. Patients will
be randomly placed into one of two groups. In the first group during the procedure, the
anesthesiologist will not be able to see the numbers (MV, TV, and RR) displayed screen of the
monitor, so the data will not be used to guide the patient's clinical care. In the second
group, the anesthesiologist will be able to see the RVM measurements of MV, TV, and RR to
evaluate the effect of the interventions. Monitoring for both groups will continue in the
recovery room, until discharge.

The purpose of this study is to assess the utility of the ExSpiron Respiratory Variation
Monitor in patients undergoing an interventional procedure with anesthesia. The primary
outcome measure will be the average minute ventilation of the patient during the procedure.
This study will also examine the correlation between clinical interventions such as drug
administrations or airway maneuvers with data from the monitor. Additionally the study may
provide information about the ability of this new monitoring system to prevent hypoxemia
during these procedures and to consider its utility, compared with capnography, to detect
hypopnea.

Background Assessing the adequacy of ventilation during Monitored Anesthesia Care (MAC) and
sedation is difficult. Agents used to provide procedural sedation can depress ventilatory
drive and can interfere with airway patency, making it much more likely that the patient will
hypoventilate and experience partial or complete obstruction to ventilation. [It is actually
clinically easier to administer general anesthesia and insert an airway management device
such as an endotracheal tube or a laryngeal mask airway , however given the superior recovery
profile following sedation vs. general anesthesia, it is usually preferable to administer
sedation, if the procedure can be performed with its use.] The American Society of
Anesthesiologists maintains a database of closed malpractice claims which allows analysis of
patterns of injury. A study considering claims from MAC/sedation cases found that 40% of the
MAC claims resulted in death or brain damage, that 25% of the claims that were associated
with oversedation/hypoventilation occurred in the endoscopy suite, and that 44% of the
oversedation cases could have been prevented by better monitoring.1 A study comparing claims
from remote locations (such as endoscopy) with operating rooms, found that 50% of remote
location claims involving monitored anesthesia care, the proportion of claims for death was
increased in remote location claims [54 vs. 29% (operating room claims)], respiratory
damaging events were more common in remote location claims (44 vs. 20%), with inadequate
oxygenation/ventilation the most common specific event (21 vs. 3% in operating room claims),
and that remote location claims were more often judged as being preventable by better
monitoring (32 vs. 8% for operating room claims).2

Upper endoscopy procedures, such as upper GI endoscopy and endoscopic retrograde
cholangiopancreatography (ERCP), are particularly challenging where the anesthesiologist has
limited access to the patient's head and is working in darkened rooms. Indeed investigators
have found it very difficult to find a combination of propofol and short acting opioid that
allows instrumentation of the esophagus without "intolerable ventilatory depression".3 Trying
to assess ventilation by observing chest excursion or listening to ventilation with a
stethoscope under these conditions can be difficult and can be done only periodically.
Side-stream nasal cannula end-tidal capnography offers a possible solution, but the cannula
can become dislodged and the proceduralist's endoscope often interferes with its function.
End-tidal capnography in the non-intubated patient is very insensitive to changes in minute
ventilation. At best, this technology can usually assess only the presence or absence of
ventilation: there is limited ability to judge the adequacy of ventilation or to quantify
it.4

The Study Device The ExSpiron Respiratory Volume Monitor (Respiratory Motion, Inc., Waltham
MA) has FDA 501(k) clearance to be used for patient care. It consists of a proprietary PadSet
that is placed on the chest in the mid-axillary line and connected to a free standing
monitor. This monitor measures and analyzes the changes in thoracic electrical impedance that
occur during the respiratory duty cycle. It is able to quantify respiratory rate and also
determine tidal volume and minute ventilation as well as graphically display changes in lung
volumes. It has been shown to accurately measure the effect of interventions (medications,
airway maneuvers) in endoscopy patients.5 Preliminary work has determined optimal lead
placement demonstrated excellent correlation to spirometry with an R value of 0.94-0.98 and
excellent accuracy and precision.6

Preliminary work cited below has shown that the monitor provides information about the effect
of medications and airway maneuvers on breathing patterns that is not available with routine
monitoring. This study seeks to extend that knowledge by investigating whether using this
information in real-time results in different respiratory measurements compared to patients
with routine monitoring.

Inclusion Criteria:

- Subjects undergoing upper gastrointestinal endoscopy

Exclusion Criteria:

- Patients with a history of thoracotomy with resection of lung tissue

- Patients with a history of severe chronic obstructive pulmonary disease (defined as an
inability to climb a flight of stairs or FEV1/VC of less than 30% of predicted)

- BMI greater than 43.
We found this trial at
1
site
Burlington, Vermont 05405
Principal Investigator: Donald M Mathews, M.D.
Phone: 802-847-4259
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mi
from
Burlington, VT
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