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NCT Number: NCT06521489

Asymmetrical HFNCO vs Standard HFNCO Post Cardiac Surgery Patients

High-flow oxygen therapy has been applied after extubation in cardiac surgery patients with a well-known successful efficacy. The current authors plan to conduct a prospective, randomized, controlled study of the Asymmetrical device Nasal Cannula High Flow Oxygenation (HFNCO) application on high flow (60L/min) with 60% fiO2 administration versus Conventional device Nasal Cannula High Flow Oxygenation (HFNCO) application on high flow (60L/min) with 60% fiO2 administration and versus Conventional oxygen treatment (Venturi mask) after extubation of patients undergoing elective or non-elective cardiac surgery.

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Key information

Conditions

Hypoxemic Respiratory Failure Respiration Disorders Respiratory Insufficiency Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Evangelismos General Hospital of Athens

Athens, Attica, 10676, Greece

About this study

Over the last decade, High Flow Nasal Cannula Oxygenation,(HFNCO) has proven successfully its capability in the management of hypoxemic respiratory failure patients post cardiac surgery. Efficient oxygenation has been recorded in meta-analyses on study population research with BMI > 30 . Moreover, in a recent meta-analysis, it has been documented that the use of HFNCO required less need for upgrade of respiratory support . Similar findings were documented in a study of two different variations of HFNCO treatment as compared with Conventional oxygen therapy (Venturi mask) .

A modified version (Asymmetrical) of HFNCO came on the surface recently whereas the (L) nasal prong has a larger diameter compared with the (R) prong of the nasal cannula.

Research results on hypoxemic patients and laboratory models also revealed interesting measurements on specific respiratory parameters such as minute volume ventilation, respiratory rate, and work of breathing as compared with conventional HFNCO. In addition, there were documented higher resistance flow rates which achieved higher PEEP rates in favor of lung alveoli.

On the other hand, there exists documentation with positive aspects that support the use of a non-rebreathing mask / Venturi mask or surgical mask fixed on top of nasal prongs of HFNCO to augment the fiO2 which finally ends up on the patient.

Aim of the study. The primary goal of the study is the efficacy of the Asymmetrical HFNCO on cardiac surgical patients post-extubation as compared with Conventional HFNCO The secondary goal of the study is the comparison of initial Asymmetrical HFNCO parameters versus a) the avoidance of upgrading Asymmetrical HFNCO supported by a non-rebreathing mask fixed on top of that, versus b) the avoidance of upgrading Asymmetrical HFNCO to Non-Invasive Ventilation (NIV).

The tertiary goal of the study is the comparison of all three patient groups; a) Asymmetrical HFNCO, 60L/min, FiO2 60%, b) Conventional HFNCO 60l/min, FiO2 60%, c) Conventional oxygen therapy Venturi mask 12l/min, FiO2 60% regarding the use of treatment on patients with ΒΜΙ > 30 and regarding respiratory parameters (respiratory rate, pO2/ FiO2, spO2, use of accessory muscles, dyspnoea, comfort and tolerance by using the visual analog scale).

Additional goals of the study are to compare all three patient groups regarding ICU Length of Stay, Hospital Length of Stay, rates of ICU re-admission and re-intubation, and any other respiratory / non-respiratory complications and adverse events ( respiratory-chest infection, pneumothorax, delirium, grand mal, acute renal failure, major bleeding - tamponade, cardiac arrest) . Moreover, the rate of failure of the initial treatment will be recorded (as a major measure of treatment efficacy).

Method This is a prospective, non-blinded, randomized study in post-extubated cardiac surgery patients. The study population will consist of three patient groups;

  • Asymmetrical HFNCO, 60l/min, FiO2 60%,
  • Conventional HFNCO 60l/min, FiO2 60%,
  • Conventional oxygen therapy Venturi mask 12l/min, FiO2 60%

Treatment "failure" will be defined as any crossover from one treatment to another due to the patient's respiratory distress and discomfort. To be more specific, switch from Asymmetrical HFNCO to Conventional HFNCO, or switch from Asymmetrical HFNCO to Conventional oxygen therapy supported by a non-rebreathing mask fixed on top of a nasal cannula, or need for more advanced respiratory support such as non-invasive ventilation or invasive mechanical ventilation

Any implemented treatment would also be defined as "failure" when any irreversible (for at least 48 hours) FiO2/gas-mixture flow escalation might be needed, either it is being recorded in study groups 1 & 2 or control group.

"Failure" would also defined as any irreversible (> 48 hours) crossover from either the HFNCO group to standard practice (Venturi mask) or the need for more advanced respiratory support such as non-invasive ventilation or invasive mechanical ventilation.

An initial power analysis was based on a predicted, average failure rate of 15% in the HFNCO groups and a failure rate of 51% in the control group; this analysis yielded the need for enrollment of a total of 41 HFNCO patients and 21 controls for alpha = 0.05 and power=0.80. To ensure equal numbers of patients in each one of the 2 HFNCO groups, the authors decided to enroll 42 HFNCO patients (n=21 for each NHF group) and 21 controls, resulting in a total enrollment of 63 patients

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Cardiac ICU adult patients
  • >18 years
  • After elective or urgent cardiac surgery
  • Successful Spontaneous Breathing Trial (SBT) with T-piece and FiO2=60%.
  • pO2/ FiO2 <150
  • Hemodynamically stable (160>SAP>90mmHg)

Exclusion criteria

  • Obstructive Sleep Apnea Syndrome supported by CPAP mask on ventilator
  • COPD, officially diagnosed, respiratory failure - on exacerbation with serum blood pH <7,35.
  • Patients with tracheostomy,
  • DNR status,
  • Glasgow Coma Scale score < 13,
  • Insufficient knowledge of the Greek Language
  • Visual or hearing impairment.

Treatment and study plan

Asymmetrical High Flow Nasal Cannula Oxygenation

Device

Asymmetrical High Flow Nasal Cannula Oxygenation will be implemented in this study group. (1st study group, 60l/min airflow, 60% fiO2)

Conventional High Flow Nasal Cannula Oxygenation

Device

Conventional High Flow Nasal Cannula Oxygenation will be implemented in this study group. (2nd study group, 60l/min airflow, 60% fiO2)

Primary outcomes

  1. Successful weaning (i.e. absence of treatment failure) from Asymmetrical Nasal Cannula High Flow Oxygenation post-extubation from cardiac surgery within at least 48 hours

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful weaning (i.e. absence of treatment failure as further described in methods) would be defined as = 0 when there would be avoided successfully any alternation with Conventional Nasal Cannula High Flow Oxygenation, Non Invasive Ventilation, or re-intubation

    For all groups: Unsuccessful weaning (i.e. actual treatment failure as further described in methods) would be defined as =1 when there would not be avoided any alternation with Conventional Nasal Cannula High Flow Oxygenation, Non Invasive Ventilation or re-intubation.

Secondary outcomes

  1. Successful maintenance of Respiration rate within the normal range (12-20/min) on initial airflow at 60 L/min, 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of Respiratory rate within normal range would be defined as = 0. Unsuccessful (=1) if exceeds normal range (12-20/min).

    Continuous monitoring and recording of implementation of airflow at 60L/min, 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

  2. Successful maintenance of Respiration rate within the normal range (12-20/min) on the initial airflow of 60 L/min, 60% fiO2 with Conventional Nasal Cannula High-Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of Respiratory rate within normal range would be defined as = 0. Unsuccessful (=1) if exceeds normal range (12-20/min).

    Continuous monitoring and recording of implementation of airflow at 60L/min, 60% fiO2 on Conventional Nasal Cannula High Flow Oxygenation

  3. Successful maintenance of Respiration rate within normal range (12-20/min) with Venturi mask , FiO2: 60%, 15L/min

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of Respiratory rate within normal range would be defined as = 0. Unsuccessful (=1) if exceeds normal range (12-20/min).

    Continuous monitoring and recording of implementation of Venturi mask, FiO2: 60%, 15L/min

  4. Recording of pO2/FiO2 ratio with initial air flow at 60 L/min & 60% fiO2 with Asymmetrical Nasal Cannula High Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Continuous monitoring and recording of implementation of Asymmetrical Nasal Cannula High Flow Oxygenation with airflow at 60 L/min & 60% fiO2

  5. Recording of pO2/FiO2 ratio with initial airflow at 60 L/min & 60% fiO2 with Conventional Nasal Cannula High Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Continuous monitoring and recording of implementation of Conventional Nasal Cannula High Flow Oxygenation with airflow at 60 L/min & 60% fiO2

  6. Recording of pO2/FiO2 ratio with Venturi mask, 60% fiO2, 12l/min

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Continuous monitoring and recording of implementation of Venturi mask, 60% fiO2, 12l/min

  7. Successful maintenance of saturation O2 in Hemoglobulin within normal range with initial airflow at 60 L/min & 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of saturation O2 in Hemoglobulin > 92% would be defined as = 0.

    If saturation O2 < 92 %, it would be defined as Unsuccessful = 1. Continuous monitoring and recording of implementation of initial airflow at 60 L/min & 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

  8. Successful maintenance of saturation O2 in Hemoglobulin within normal range with initial airflow at 60 L/min & 60% fiO2 on Conventional Nasal Cannula High Flow Oxygenation

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of saturation O2 in Hemoglobulin > 92% would be defined as = 0.

    If saturation O2 < 92 %, it would be defined as Unsuccessful = 1. Continuous monitoring and recording of implementation of initial airflow at 60 L/min & 60% fiO2 on Conventional Nasal Cannula High Flow Oxygenation

  9. Successful maintenance of saturation O2 in Hemoglobulin within normal range with Venturi mask, 60% fiO2, 12l/min

    Time frame: Up to at least 48 hours post extubation or until ICU discharge (predicted cardiothoracic ICU stay could occasionally extend up to 7 days)]

    Successful maintenance of saturation O2 in Hemoglobulin > 92% would be defined as = 0.

    If saturation O2 < 92 %, it would be defined as Unsuccessful = 1. Continuous monitoring and recording of implementation of Venturi mask, 60% fiO2, 12l/min

  10. Mobilization of accessory respiratory muscles with initial airflow at 60 L/min & 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    Success would be defined as = 0 when there would be no mobilization of accessory respiratory muscles. Failure would be defined as = 1 when there would be recorded any mobilization and use of accessory respiratory muscles.

    Continuous monitoring and recording of implementation of initial airflow at 60 L/min & 60% fiO2 on Asymmetrical Nasal Cannula High Flow Oxygenation

  11. Mobilization of accessory respiratory muscles with initial airflow at 60 L/min & 60% fiO2 on Conventional Nasal Cannula High Flow Oxygenation.

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    Success would be defined as = 0 when there would be no mobilization of accessory respiratory muscles. Failure would be defined as = 1 when there would be recorded any mobilization and use of accessory respiratory muscles.

    Continuous monitoring and recording of implementation of initial airflow at 60 L/min & 60% fiO2 on Conventional Nasal Cannula High Flow Oxygenation.

  12. Mobilization of accessory respiratory muscles with Venturi mask, 60% fiO2, 12l/min

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    Success would be defined as = 0 when there would be no mobilization of accessory respiratory muscles. Failure would be defined as = 1 when there would be recorded any mobilization and use of accessory respiratory muscles.

    Continuous monitoring and recording of implementation of Venturi mask, 60% fiO2, 12l/min

  13. Comfort and tolerance of treatment with Visual Analogue Scale on Asymmetrical Nasal Cannula High Flow Oxygenation with initial airflow at 60 L/min & 60% fiO2

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    To monitor and record a patient's comfort with the Visual Analogue Scale diagnostic tool on a scale of 1 to 10. The patients would give the number 10 should they feel comfortable with their respiratory function and have no difficulty breathing. Number 10 on the Scale would mean the best outcome and number 1 would mean the worst outcome respectively

  14. Comfort and tolerance of treatment with Visual Analogue Scale on Conventional Nasal Cannula High Flow Oxygenation with initial airflow at 60 L/min & 60% fiO2

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    To monitor and record a patient's comfort with the Visual Analog Scale diagnostic tool on a scale of 1 to 10. The patients would give the number 10 should they feel comfortable with their respiratory function and have no difficulty breathing. Number 10 on the Scale would mean the best outcome and number 1 would mean the worst outcome respectively

  15. Comfort and tolerance of treatment with Visual Analogue Scale with Venturi mask, 60% fiO2, 12l/min

    Time frame: Post extubation period up to 48 hours or ICU discharge (if cardiothoracic ICU stay was <48 hours)

    To monitor and record a patient's comfort with the Visual Analog Scale diagnostic tool on a scale of 1 to 10. The patients would give the number 10 should they feel comfortable with their respiratory function and have no difficulty breathing. Number 10 on the Scale would mean the best outcome and number 1 would mean the worst outcome respectively

  16. Length of Stay in the ICU

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the total length of stay in the ICU since admission post surgery

  17. Length of Stay in the Hospital

    Time frame: Post cardiothorasic ICU admission period up to actual hospital discharge

    There will be recorded the total length of stay in the hospital since ICU admission

  18. Number of participants with death in the cardiothoracic ICU post extubation

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants that will pass away post extubation in the ICU

  19. Number of participants with Atrial Fibrillation in the ICU post extubation

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants that will present Atrial Fibrillation post extubation in the ICU

  20. Number of participants with any Adverse Events in the ICU (respiratory-chest infection, pneumothorax, delirium, grand mal, acute renal failure, major bleeding - tamponade )

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants that will present any Adverse Events (respiratory-chest infection, pneumothorax, delirium, grand mal, acute renal failure, tamponade ) post extubation in the ICU

  21. Number of participants with any Adverse Events in the Hospital (respiratory-chest infection, pneumothorax, delirium, grand mal, acute renal failure, major bleeding - tamponade, cardiac arrest )

    Time frame: Post cardiothorasic ICU admission period up to 3 months or until actual Hospital discharge

    There will be recorded the number of participants that will present any Adverse Events (respiratory-chest infection, pneumothorax, delirium, grand mal, acute renal failure, tamponade, cardiac arrest) in the Hospital

  22. Percentage of participants presenting unsuccessful (failed) implementation of Asymmetrical Nasal Cannula High Flow Oxygenation treatment

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants who will fail to comply with the treatment due to failing to maintain their respiratory parameters within normal range, or due to presenting intolerance and discomfort to the implementation of Asymmetrical Nasal Cannula High Flow Oxygenation treatment

  23. Percentage of participants presenting unsuccessful (failed) implementation of Conventional Nasal Cannula High Flow Oxygenation treatment

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants who will fail to comply with the treatment due to failing to maintain their respiratory parameters within normal range, or due to presenting intolerance and discomfort to the implementation of Conventional Nasal Cannula High Flow Oxygenation treatment

  24. Percentage of participants presenting unsuccessful (failed) implementation of Venturi mask oxygen therapy

    Time frame: Post cardiothoracic ICU admission period up to 48 hours or untiI actual cardiothoracic ICU discharge]

    There will be recorded the number of participants who will fail to comply with the treatment due to failing to maintain their respiratory parameters within normal range, or due to presenting intolerance and discomfort to the implementation of Venturi mask oxygen therapy

  25. Number of participants with re-intubation in the ICU

    Time frame: Post cardiothorasic ICU admission period up to 3 months or until actual Hospital discharge

    There will be recorded the number of participants that will be re-intubated due to deterioration of their respiratory parameters.

Sponsors and collaborators

Lead sponsor

National and Kapodistrian University of Athens

Other

Registry information

Official study title

Study of Asymmetrical High Flow Nasal Cannula Oxygenation (HFNCO) vs Standard HFNCO on Cardiac Surgical Patients Postoperatively

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Jul 26, 2024
Registry last updated
Mar 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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