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Trial record 60 of 570 for:    CARBON DIOXIDE AND anesthesia

Airvo/Optiflow High Flow Nasal Oxygenation During Microlaryngeal Surgery

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: NCT02780518
Recruitment Status : Withdrawn (Airvo 2 not suitable for CO2 clearance, awaiting Optiflow THRIVE machine)
First Posted : May 23, 2016
Last Update Posted : May 1, 2017
Information provided by (Responsible Party):
Singapore General Hospital

Brief Summary:
Optiflow high flow nasal cannula (HFNC) oxygenation is a technique to provide oxygen to patients when they are paralysed under general anaesthesia. Their lungs are not moving, but the high flow allows oxygen to travel into their lungs. This is called 'apnoeic ventilation'. The investigators will be using this for patients undergoing surgery for their throat.

Condition or disease Intervention/treatment Phase
Throat Disorders Device: Airvo Not Applicable

Detailed Description:


Optiflow high flow nasal cannula (HFNC) oxygenation is a suitable technique for oxygenation and ventilation (apnoeic ventilation) for patients undergoing microlaryngeal surgery.


  1. Measure continuous pulse oximetry (oxygenation) and intermittent subglottic catheter sampling of end tidal carbon dioxide levels (ventilation) in the distal trachea during HFNC oxygenation
  2. Measure intra-tracheal airway pressure during HFNC oxygenation


As a pilot study, the investigators will recruit up to 20 patients within a 12 month period scheduled for elective microlaryngeal surgery and high frequency jet ventilation. Standard monitoring and standard conduct of anaesthesia will be carried out: induction of general anaesthesia, insertion of a narrow catheter into the trachea and insertion of laryngeal mask airway. In addition, the study device (HFNC) will be placed into the entrance of the patient's nostrils. After removal of the laryngeal mask, HFNC oxygenation will commence. A surgical suspension laryngoscope will be inserted for microlaryngeal surgery (standard technique). The investigators will measure the adequacy of gas exchange, during of HFNC oxygenation and complications (cardiovascular, airway and respiratory). Data will be stored on a secure REDCap (Research Electronic Data Capture) system.


HFNC oxygenation is a novel technique that depends on apnoeic oxygenation. Even though the patient is paralysed and not breathing, oxygenation and carbon dioxide clearance still occurs. This is due to the difference between the alveolar rates of oxygen removal and carbon dioxide excretion which generates a negative pressure gradient. Oxygenation of the patient is therefore due to the high inspiratory fraction of oxygen, apnoeic ventilation and the small continuous positive airway pressure caused by the high flow of gas. This pressure increases lung volume and recruits collapsed alveoli. Carbon dioxide clearance is due to gas mixing and flushing of the airway dead space. The additional humidification of the high flow oxygen prevents mucociliary damage of the airway.

HFNC has been shown beneficial in pre-oxygenation, oxygenation after extubation, and in the treatment of respiratory failure and heart failure. New uses in difficult airway management are now emerging. However, the main case series of HFNC use in difficult airways did not measure intra-operative airway pressures end tidal oxygen and carbon dioxide; these gases were only measured at the end of surgery and when a definitive airway was inserted. As far as the investigators are aware, there are no data on intra-operative, intra-tracheal airway pressures or oxygen or carbon dioxide during HFNC oxygenation. Our study aim is to fill this knowledge gap.

Potential benefits and risks:

The use of HFNC removes obstacles form the surgical field and this may make surgery easier and quicker to perform. Risks include: failed gas exchange, but this is minimized by abandoning HFNC oxygenation and instituting tracheal catheter jet ventilation via the in situ jet catheter (standard practice).

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 0 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Airvo/Optiflow High Flow Nasal Oxygenation During Microlaryngeal Surgery - Assessing Effectiveness of Oxygenation and Carbon Dioxide Clearance
Study Start Date : June 2016
Estimated Primary Completion Date : June 2017
Estimated Study Completion Date : June 2017

Arm Intervention/treatment
Experimental: Airvo
All patients scheduled for elective microlaryngeal surgery under general anaesthesia and subglottic high frequency jet ventilation
Device: Airvo
Applying high flow nasal oxygen

Primary Outcome Measures :
  1. Number of patients with inadequate oxygenation as measured by pulse oximetry (SpO2<94%). [ Time Frame: 30 minutes ]
    Continuous pulse oximetry will be monitored for participants during the study.

Secondary Outcome Measures :
  1. Number of patients with inadequate carbon dioxide clearance (end tidal CO2>55 mmHg) [ Time Frame: 30 minutes ]
    End tidal carbon dioxide will be measured by the sublgottic catheter already in situ in the trachea by continuous passive sampling and by intermittent low frequency jet ventilation

  2. Number of participants with treatment-related adverse events as assessed by CTCAE v4.03 [ Time Frame: 30 minutes ]
    The investigator will report the number of participants wtih adverse events that are related to treatment

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 99 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

1. Patients undergoing elective microlaryngeal surgery requiring general anaesthesia and jet ventilation. They must have a physical status of the American Society of Anesthesiologists (ASA) grade I/II and age 21 years or older.

Exclusion Criteria:

  1. Patients with history of previous difficult endotracheal intubation
  2. Patients with two or more predictors of difficult mask ventilation or difficult intubation or the combination of both
  3. Patients with ASA grading of III and above are excluded from the study
  4. Patients needing a rapid sequence induction for rapid securement of the airway
  5. Pregnant women
  6. Patients below the age of 21 years old
  7. Patients unfit to give consent
  8. Patients with nasal or sinus disease or problems
  9. Patients with infective laryngeal disease e.g. papillomatosis

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): NCT02780518

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Singapore General Hospital
Singapore, Singapore, 169608
Sponsors and Collaborators
Singapore General Hospital
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Principal Investigator: Patrick Wong, MBBS FRCA Singapore General Hospital

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Responsible Party: Singapore General Hospital Identifier: NCT02780518     History of Changes
Other Study ID Numbers: 1605 Airvo Optiflow
First Posted: May 23, 2016    Key Record Dates
Last Update Posted: May 1, 2017
Last Verified: April 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Keywords provided by Singapore General Hospital:
carbon dioxide