The Effect of High-flow Nasal Oxygen Flow Rate on Gas Exchange During Apnoea
- Conditions
- ApneaRespiration; ArrestAnesthesia
- Interventions
- Procedure: Apnoeic oxygenation
- Registration Number
- NCT05124093
- Lead Sponsor
- University College Hospital Galway
- Brief Summary
Apnoeic oxygenation refers to oxygenation that occurs through the insufflation of oxygen into the lungs in the absence spontaneous respiration or positive pressure ventilation. It is used to extend the time to desaturation at induction of anaesthesia and as a primary oxygenation technique during airway surgery. The impact of high-flow nasal oxygen flow rate selection on gas exchange is poorly understood. Participants in this study will be randomised to receive a certain nasal oxygen flow rate during apnoea and its effect on gas exchange will be measured by blood gas analysis.
- Detailed Description
Apnoeic oxygenation with high-flow nasal oxygen has been proposed to result in carbon dioxide clearance. However, this has been poorly quantified.
This study will compare use of nasal oxygen at different flow rates during apnoea with that of a control that does not receive nasal oxygen. Participants are anaesthetised after standardised pre-oxygenation with high-flow nasal oxygen, after which they will receive one of three nasal oxygen flow rates (0, 70, 120 L/min).
The rate of carbon dioxide elevation will be measured by arterial blood gas analysis after the onset of apnoea and compared between the three groups to discern the relative rates of carbon dioxide clearance after the first minute of apnoea. The effect of nasal oxygen flow rate on oxygenation will also be measured.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 114
- 18 years of age or older
- ASA 1 or 2
- Receiving a general anaesthetic for non-emergent surgery
- ASA score ≥3
- BMI ≥ 30 kg/m2
- Nasal obstruction
- Baseline SpO2 ≤95% on room air
- Anticipated difficult airway management
- Requirement for awake intubation
- Pregnancy
- Positive PCR test for coronavirus in preceding 14 days.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Apnoeic oxygenation with high-flow nasal oxygen at 70 L/min (HFNO) Apnoeic oxygenation 100% oxygen is administered via high-flow nasal cannulae at 70L/min from the onset of apnoea until four minutes of apnoea has completed. Apnoea without apnoeic oxygenation Apnoeic oxygenation High-flow nasal oxygen administration ceases at the onset of apnoea. Apnoeic oxygenation with high-flow nasal oxygen at 120 L/min (uHFNO) Apnoeic oxygenation 100% oxygen is administered via high-flow nasal cannulae at 120L/min from the onset of apnoea until four minutes of apnoea has completed.
- Primary Outcome Measures
Name Time Method Rise in arterial partial pressure of carbon dioxide Between 1 and 4 minutes of apnoea The rate of rise of the partial pressure of carbon dioxide between 60 seconds and 240 seconds of apnoea as measured by arterial blood gas analysis.
- Secondary Outcome Measures
Name Time Method Time to oxygen desaturation Immediately after the intervention The time period from the onset of apnoea (determined by visual inspection) until an oxygen saturation of 92% is measured by pulse oximetry.
Partial pressure of oxygen during apnoea Following high-flow nasal oxygen administration As measured by blood gas analysis
Change in carbon dioxide elevation before and after HFNO administration Between 3 and 5 minutes of apnoea As measured by blood gas analysis
Carbon dioxide elevation during the first minute of apnoea Between 0 and 1 minute of apnoea As measured by blood gas analysis
Change in acid-base status during apnoea At 1 minute intervals during apnoea As measured by blood gas analysis
Trial Locations
- Locations (1)
University Hospital Galway
🇮🇪Galway, Ireland