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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03886454
Recruitment Status : Completed
First Posted : March 22, 2019
Last Update Posted : August 28, 2019
Natalie V. Zucker Research Grant
Information provided by (Responsible Party):
Tufts Medical Center

Brief Summary:
This study aims to characterize airflow patterns during bronchoscopy under conscious sedation, and determine the incidence of obstructive and central respiratory events. The investigators also plan to monitor the degree and frequency of oxygen desaturation throughout the procedure. To achieve this, investigators use a physiologic monitoring device (NOX T3, K082113) that has been FDA approved for the screening and diagnosis of sleep disordered breathing [1]. The results from this pilot study will be used to assess the feasibility of a prospective study utilizing continuous external negative pressure (Pneuway). This negative pressure is applied through a neck mask to alleviate upper airway collapsibility and can potentially decrease the number of apneas during bronchoscopy under conscious sedation [2].

Condition or disease
Conscious Sedation Bronchoscopy

Detailed Description:

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].


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 investigators will report on patients' demographics. The study investigators will also present the incidence of apneic respiratory events and characterize them as obstructive or centrals. Investigators will further differentiate obstructive respiratory events to either apneas or hypopnea. Data on oxygen desaturations unrelated to apneic events will also be recorded.

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Study Type : Observational
Actual Enrollment : 33 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Incidence and Nature of Respiratory Impairment in Consecutive Patients Undergoing Bronchoscopy Under Conscious Sedation: A Pilot Study
Actual Study Start Date : June 19, 2017
Actual Primary Completion Date : June 1, 2019
Actual Study Completion Date : July 1, 2019

Resource links provided by the National Library of Medicine

Primary Outcome Measures :
  1. The incidence of obstructive and central apneic events. [ Time Frame: Throughout the bronchoscopic procedure. ]
    Obstructive apnea are defined as more than 90% cessation of air-flow that lasts for at least 10 seconds, despite the presence of respiratory and abdominal muscle effort. Obstructive hypopnea is when more than 30% cessation of air-flow occurs that lasts for at least 10 seconds, and is associated with oxygen desaturation of at least 3% from baseline. Central apnea is when cessation of air-flow occurs secondary to absent respiratory and abdominal muscle effort, that lasts for at least 10 seconds.

Secondary Outcome Measures :
  1. Oxygen desaturation [ Time Frame: Throughout the bronchoscopic procedure. ]
    Oxygen desaturation of more than 3% from baseline which are unrelated to apneic events.

  2. Need for escalation of care [ Time Frame: Throughout the bronchoscopic procedure. ]
    Need for escalation of care, including but not limited to, increasing supplemental oxygen, jaw thrust, patient stimulation or interrupting the administration of conscious sedation drug.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
All patients who have been referred to the pulmonary division at Tufts Medical Center for bronchoscopy

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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03886454

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United States, Massachusetts
Tufts Medical Center
Boston, Massachusetts, United States, 02111
Sponsors and Collaborators
Tufts Medical Center
Natalie V. Zucker Research Grant
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Principal Investigator: Khalid Ismail, MD Tufts Medical Center
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Responsible Party: Tufts Medical Center Identifier: NCT03886454    
Other Study ID Numbers: IRB # 12489
First Posted: March 22, 2019    Key Record Dates
Last Update Posted: August 28, 2019
Last Verified: August 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: Plan is to make IPD available to sommetrics Inc. to review once the study is complete. Data would include all the information obtained on the NOX-T3 device during conscious sedation which includes, but is not limited to, heart rate, respiratory rate, air flow through nasal cannula, oxygen saturation and chest and abdominal wall movements.
Supporting Materials: Study Protocol
Statistical Analysis Plan (SAP)
Clinical Study Report (CSR)
Time Frame: IPD will become available after completion of the study and will be available to review for 1 year thereafter.
Access Criteria: IPD that is acquired by the NOX-T3 device is transferred to NOX-T3 software. Plan is to share IPD with sommetrics Inc. via that software.

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Studies a U.S. FDA-regulated Drug Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by Tufts Medical Center:
Central apnea
Obstructive apnea
Oxygen desaturation
Escalation of Care
conscious sedation
Respiratory impairment
Additional relevant MeSH terms:
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Respiratory Insufficiency
Respiration Disorders
Respiratory Tract Diseases