Incidence and Nature of Respiratory Impairment in Consecutive Patients Undergoing Bronchoscopy Under Conscious Sedation: A Pilot Study

Background and Rationale:

Diagnostic bronchoscopic procedures are commonly performed in patients with various forms of
pulmonary disorders associated with abnormal chest imaging. During these procedures, the
vocal cords are intubated using a flexible scope. Patients need sedation and analgesia, and
conscious sedation is typically administered. Hypoxemia is a potential complication during
bronchoscopy. Contributing factors in addition to the underlying lung pathology, include
depression of the respiratory center and decreased upper airway muscle tone that occur during
conscious sedation [3]. Upper airway obstruction including obstructive apnea is often
unrecognized during these procedures till hypoxemia is apparent [4]. Propofol, a common drug
used for conscious sedation, is known to cause respiratory depression, and potentially
central and/or obstructive apneas with a direct dose-response pattern [5]. Others, including
benzodiazepines and opiates, can also cause respiratory depression leading to central or
obstructive events. Respiratory depression is potentiated when any of the above medications
are combined [6].

Objectives:

The objective of the study is to identify the incidence of airflow limitation during
bronchoscopy under conscious sedation, and further characterize it as obstructive or central.
The primary endpoint is the incidence of obstructive and central apneic events during
bronchoscopic procedures. The secondary outcomes include incidence of oxygen desaturation and
need for escalation of care.

Study Design:

After informed consent is obtained, the NOX-T3 monitoring system, a commonly used portable
sleep device that detects obstructive and central apneas, is placed prior to starting the
procedure, and remains in place up to 30 minutes following the procedure. The NOX-T3
monitoring system includes a nasal cannula that sits over the nares, an elastic band that
goes around the chest, and another one that goes around the abdomen, and a finger probe that
is placed on the index finger. All subjects undergo bronchoscopy with standard of care
including the monitoring of blood pressure, respiratory rate and oxygen saturation. All
subjects have the NOX-T3 applied in addition to standard of care monitoring. Data is assessed
following the completion of the procedure. Subjects' participation in this study ends at the
completion of their standard of care visit. All the NOX-T3 studies are scored and interpreted
by study investigators.

Data Management:

This is an observational and descriptive study with an estimated sample size of 30. Data
collected will be reviewed with a statistician and we will report on patients' demographics.
We will also present the incidence of apneic respiratory events and characterize them as
obstructive or centrals. We will further differentiate obstructive respiratory events to
either apneas or hypopnea. Data on oxygen desaturations unrelated to apneic events will also
be recorded.

Inclusion Criteria:

1. Patients with respiratory pathology that require bronchoscopy for further diagnostic
evaluation, as part of standard of care

2. Age of 18 years or older.

3. Our study does not include the recruitment of vulnerable populations such as
cognitively impaired adults, pregnant women, pregnant minors, minors, wards of the
state, non-viable neonates, neonates of uncertain viability and prisoners.

Exclusion Criteria:

1. Oxygen requirement of more than 4 Liter prior to procedure.

2. Intubation or any airway support.

3. Presence of severe cardiopulmonary or neurologic disease as determined by the
investigator.

4. Nasal congestion/obstruction preventing proper placement and monitoring of air flow

5. Inability to provide informed consent.

6. All vulnerable population mentioned above.