Clinical trial NCT05124093: The Effect of High-flow Nasal Oxygen Flow Rate on Gas Exchange During Apnoea
Official title: A Randomised Controlled Trial of Apnoeic Oxygenation With No-flow vs High-flow vs Ultra High-flow Nasal Oxygen
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Apnea
Respiration; Arrest
Anesthesia
Lead sponsor: University College Hospital Galway
Sponsor class: OTHER
First posted: 2021-11-17
Enrollment: 114
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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.

Eligibility criteria: Inclusion Criteria:

* 18 years of age or older
* ASA 1 or 2
* Receiving a general anaesthetic for non-emergent surgery

Exclusion Criteria:

* 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.

Primary outcomes:
measure: Rise in arterial partial pressure of carbon dioxide
timeFrame: Between 1 and 4 minutes of apnoea
Secondary outcomes:
measure: Partial pressure of oxygen during apnoea
timeFrame: Following high-flow nasal oxygen administration
measure: Time to oxygen desaturation
timeFrame: Immediately after the intervention
measure: Change in carbon dioxide elevation before and after HFNO administration
timeFrame: Between 3 and 5 minutes of apnoea
measure: Carbon dioxide elevation during the first minute of apnoea
timeFrame: Between 0 and 1 minute of apnoea
measure: Change in acid-base status during apnoea
timeFrame: At 1 minute intervals during apnoea
Other outcomes:
Locations:
city: Galway
country: Ireland
facility: University Hospital Galway
Study officials:
affiliation: Consultant Anaesthesiologist
name: Michael Callaghan, MB BCh BAO
role: PRINCIPAL_INVESTIGATOR
References: