The Effect of High-flow Nasal Oxygen Flow Rate on Gas Exchange During Apnoea

Anesthesia Clinical Trial

— Apox-HFNO  

Official title:

A Randomised Controlled Trial of Apnoeic Oxygenation With No-flow vs High-flow vs Ultra High-flow Nasal Oxygen

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT05124093
• Other study ID #: CA2361
• Status: Completed
• Phase: N/A
• Start date: November 22, 2021
• Est. completion date: May 25, 2022

Study information

• Verified date: July 2022
• Source: University College Hospital Galway
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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 information / eligibility

• Status: Completed
• Enrollment: 114
• Est. completion date: May 25, 2022
• Est. primary completion date: May 25, 2022
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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.

Related Conditions & MeSH terms

• Anesthesia
• Apnea
• Respiration; Arrest

Intervention

Procedure:
• Apnoeic oxygenation
After 2mins 45 seconds of pre-oxygenation with high-flow nasal oxygen at Fio2 1.0 at 50L/min, anaesthesia is induced with 1-1.5mcg/kg remifentanil plus 2-3mg/kg propofol. Propofol (10mg/kg/hr) and remifentanil (0.15mcg/kg/min) infusions administered until study conclusion. At the onset of apnoea, 1mg/kg rocuronium administered. Jaw thrust performed. High-flow nasal oxygen adjusted to the randomised flow rate. Videolaryngoscopy after 1 minute of apnoea. Airway patency maintained. Tracheal intubation after 4 minutes of apnoea. Positive pressure ventilation commenced at Spo2 92%. Failure to obtain view of glottis with videolaryngoscope results in withdrawal from the study. Blood samples obtained from an arterial catheter immediately prior to commencing pre-oxygenation, after 90 and 180 seconds of pre-oxygenation, after each minute of apnoea until six minutes of apnoea, and every two minutes of apnoea thereafter, until Spo2 92%.

Locations

Country	Name	City	State
Ireland	University Hospital Galway	Galway

Sponsors (1)

Lead Sponsor	Collaborator
University College Hospital Galway

Country where clinical trial is conducted

Ireland, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Rise in arterial partial pressure of carbon dioxide	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.	Between 1 and 4 minutes of apnoea
Secondary	Partial pressure of oxygen during apnoea	As measured by blood gas analysis	Following high-flow nasal oxygen administration
Secondary	Time to oxygen desaturation	The time period from the onset of apnoea (determined by visual inspection) until an oxygen saturation of 92% is measured by pulse oximetry.	Immediately after the intervention
Secondary	Change in carbon dioxide elevation before and after HFNO administration	As measured by blood gas analysis	Between 3 and 5 minutes of apnoea
Secondary	Carbon dioxide elevation during the first minute of apnoea	As measured by blood gas analysis	Between 0 and 1 minute of apnoea
Secondary	Change in acid-base status during apnoea	As measured by blood gas analysis	At 1 minute intervals during apnoea