Nasal High Flow Therapy in Surgical Patients With Unrecognized Obstructive Sleep Apnea (POSAII)
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ClinicalTrials.gov Identifier: NCT03964376 |
Recruitment Status :
Suspended
(due to COVID-19)
First Posted : May 28, 2019
Last Update Posted : December 29, 2020
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Condition or disease | Intervention/treatment | Phase |
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Obstructive Sleep Apnea Sleep Disordered Breathing | Other: Nasal High Flow Other: Usual Care | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 190 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Prevention |
Official Title: | Nasal High Flow Therapy Versus Postoperative Usual Care in Surgical Patients With Unrecognized Obstructive Sleep Apnea: A Randomized Controlled Trial (A PHASE 2 STUDY) |
Actual Study Start Date : | October 1, 2019 |
Estimated Primary Completion Date : | June 15, 2021 |
Estimated Study Completion Date : | December 15, 2021 |

Arm | Intervention/treatment |
---|---|
Experimental: Nasal High Flow Group
Nasal High-Flow oxygen delivery will be applied starting at airflow of minimum 20 Litre/minute. It will be titrated in 15Litre/minute increments to 35 Litre/minute and a maximum 50 Litre/minute as determined by patient comfort. O2 supplementation will be managed by the anesthesia and surgical health care team to maintain the oxygen saturation level in the blood between 92-95%. In the Nasal High-Flow group, when SPO2 is in the range of 92-95%, air will be given instead of oxygen for the 1st 3 nights and during the day, if required, till discharge, whichever is earlier.
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Other: Nasal High Flow
Delivery of oxygen via OptiflowTM system (AirvoTM, Fisher & Paykel Inc.) with airflow of 20 to 50 Litre/minute |
Usual Care Group
In the usual care, patients will receive oxygen at 2-4 Litre/minute via nasal cannula or 6 Litre/minute via facemask titrated to keep SpO2 level in the range of 92-95%. When SpO2 level reaches in the range of 92-95%, oxygen delivery will be discontinued.
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Other: Usual Care
Delivery of oxygen at 2-4 Litre/minute via nasal cannula or 6 Litre/minute via face mask |
- Oxygen Desaturation Index (ODI) [ Time Frame: 72 hours ]The investigators will measure Oxygen Desaturation Index(the number of desaturation events per hour) by using Pulsox 300i for maximum of three nights post-operatively at the hospital preventing the severe desaturation in surgical patients with untreated moderate-to-severe OSA undergoing major non cardiac surgery. Higher values of ODI are considered worst. If successful, it will provide feasibility data for the performance of a large randomized clinical trial focusing on clinical outcomes and the cost effectiveness of the therapy to the health care system.
- Time (minutes) spent below 90% and 80% SpO2 (T90, T80) [ Time Frame: 72 hours ]The investigators will measure the time spent in minutes with SpO2 between 0% to %79 (T80) and the time spent in minutes with SpO2 between 0% to 89% (T90). ODI, T90 and T80 will serve as surrogate outcomes of adverse events in the pilot study. In POSA study, an increase in time spent with SpO2 <80% after surgery was associated with a higher risk of postoperative vascular events under usual care.
- Compliance to Nasal High-Flow [ Time Frame: 72 hours ]To determine the tolerability and adherence of patients with OSA to Nasal High-Flow in the wards using a 10-point numeric rating scale to grade general discomfort, in which points 0 to 3 means not comfortable, 4 to 6 means comfortable and 7 to 10 means the most comfortable.
- Titration protocol of nasal high-flow [ Time Frame: 72 hours ]The appropriate titration protocol of nasal high-flow will be measured; FiO2: flow rates.
- The rate of postoperative adverse events [ Time Frame: 30 days ]The rate of postoperative cardiovascular events will be collected during hospitalization and following discharge from hospital, emergency department (if visited) and physician records, and patient by phone at day 30. Adjudicators who are blinded to the results of the ECG, Troponin, sleep study and oximetry will evaluate outcome events.

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Ages Eligible for Study: | 45 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Adult, age ≥45 years, undergoing major elective non cardiac surgery under general and/or regional anesthesia with anticipated overnight stay or longer in hospital
- Patients with untreated moderate-to-severe Obstructive Sleep Apnea.
- STOP-Bang score 5 or higher
Exclusion Criteria:
- Predetermined need for postoperative CPAP therapy or ventilation,
- Cheyne-Stokes respiration or Central Apnea,
- Oxygen dependent due to moderate to severe chronic obstructive lung disease available Forced Expiratory Volume at 1 second of < 50% predicted) or advanced interstitial lung disease,
- Pre-existing chronic hypercapnia or obesity hypoventilation syndrome, Intracranial and otolaryngological procedures, and
- Unable to use nasal high-flow (nasal/oral malformations, pre-existing tracheostomy, planned postoperative nasal packing).

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 ClinicalTrials.gov identifier (NCT number): NCT03964376
Canada, Ontario | |
St. Michael's Hospital | |
Toronto, Ontario, Canada, M5B 1W8 | |
Toronto General Hospital | |
Toronto, Ontario, Canada, M5G 2C4 | |
Toronto Western Hopsital, Dept. of Anesthesia | |
Toronto, Ontario, Canada, M5T2S8 | |
Hong Kong | |
Prince of Wales Hospital | |
Hong Kong, Hong Kong | |
Malaysia | |
Hospital Kuala Lumpur | |
Kuala Lumpur, Malaysia | |
University Malaya Medical Centre | |
Kuala Lumpur, Malaysia | |
Singapore | |
Khoo Teck Puat Hospital | |
Singapore, Singapore | |
Singapore General Hospital | |
Singapore, Singapore |
Principal Investigator: | Frances Chung, MBBS FRCPC | University of Toronto/ University Health Network |
Responsible Party: | Dr. Frances Chung, Principal Investigator, University Health Network, Toronto |
ClinicalTrials.gov Identifier: | NCT03964376 |
Other Study ID Numbers: |
November 27,2018 |
First Posted: | May 28, 2019 Key Record Dates |
Last Update Posted: | December 29, 2020 |
Last Verified: | December 2020 |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Sleep Apnea |
Apnea Sleep Apnea Syndromes Sleep Apnea, Obstructive Respiration Disorders Respiratory Tract Diseases |
Signs and Symptoms, Respiratory Sleep Disorders, Intrinsic Dyssomnias Sleep Wake Disorders Nervous System Diseases |