Preoxygenation
Conditions
Brief summary
A trial comparing outcomes of two pre-oxygenation techniques in obstetric patients.
Detailed description
Pre-oxygenation is performed prior to general anesthesia to prevent hypoxia during airway management. It is typically performed using a standard tight-fitting face mask; however, recent advances in oxygenation have occurred through the use of trans-nasal oxygen delivery devices, such as OptiFlow. There is limited evidence of the use of OptiFlow in the pregnant patient, and as such, this study aims to show that OptiFlow is as effective at pre-oxygenation as a standard tight-fitting face-mask technique in the pregnant population.
Interventions
DEVICEFace Mask preoxygenation
Standard face mask preoxygenation.
DEVICEOptiFlow preoxygenation
Preoxygenation using transnasal humidified rapid insufflation ventilatory exchange (THRIVE).
Sponsors
University of British Columbia
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
19 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Healthy (American Society of Anesthesiologists class 1 or 2), pregnant patients ≥36 weeks gestation scheduled for elective Cesarean delivery under neuraxial anesthesia.
Exclusion criteria
* Comorbidities likely to alter outcome of respiration and gas exchange. * Patients only able to breathe through their mouth. * Patients who are in active labour. * Patients unable to tolerate a face mask being held over their mouth and nose. * Patients with a Body Mass Index ≥40kg/m2. * Patients who are unable to give informed consent.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| End Tidal Oxygen Concentration (ETO2) Following Tidal Volume Breathing Using Either Face Mask or OptiFlow | From baseline ETO2 concentration to the end of 3 minutes of tidal volume breathing | Concentration of oxygen at the end of a breath following 3 minutes of tidal volume breathing using either face mask or OptiFlow |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| End Tidal Oxygen Concentration (ETO2) Following Vital Capacity Breaths Using Either Face Mask or OptiFlow | From baseline ETO2 concentration to the end of 8 vital capacity breaths (approximately 3 minutes) | Concentration of oxygen at the end of a breath following 8 deep breaths using either face mask or OptiFlow |
Countries
Canada
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Standard Face Mask Preoxygenation Tidal volume breathing for via a face mask set at 100% oxygen and a rate of 15L/min.
Face Mask preoxygenation: Standard face mask preoxygenation. | 20 |
| Optiflow Preoxygenation Tidal volume breathing with the OptiFlow system applied at 100% oxygen and a flow rate of 30-70L/min.
OptiFlow preoxygenation: Preoxygenation using transnasal humidified rapid insufflation ventilatory exchange (THRIVE). | 17 |
| Total | 37 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Protocol Violation | 0 | 2 |
| Overall Study | Withdrawal by Subject | 0 | 1 |
Baseline characteristics
| Characteristic | Standard Face Mask Preoxygenation | Optiflow Preoxygenation | Total |
|---|---|---|---|
| Age, Continuous | 34.8 years STANDARD_DEVIATION 4.3 | 34.6 years STANDARD_DEVIATION 5.3 | 34.7 years STANDARD_DEVIATION 4.8 |
| Baseline end-tidal oxygen concentration (EtO2) | 15.9 Percentage units STANDARD_DEVIATION 1.2 | 15.9 Percentage units STANDARD_DEVIATION 1.5 | 15.9 Percentage units STANDARD_DEVIATION 1.35 |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Region of Enrollment Canada | 20 participants | 17 participants | 37 participants |
| Sex: Female, Male Female | 20 Participants | 17 Participants | 37 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 20 | 0 / 20 |
| other Total, other adverse events | 0 / 20 | 0 / 20 |
| serious Total, serious adverse events | 0 / 20 | 0 / 20 |
Outcome results
Primary
End Tidal Oxygen Concentration (ETO2) Following Tidal Volume Breathing Using Either Face Mask or OptiFlow
Concentration of oxygen at the end of a breath following 3 minutes of tidal volume breathing using either face mask or OptiFlow
Time frame: From baseline ETO2 concentration to the end of 3 minutes of tidal volume breathing
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Standard Face Mask Preoxygenation | End Tidal Oxygen Concentration (ETO2) Following Tidal Volume Breathing Using Either Face Mask or OptiFlow | 91.0 Percentage units of end-tidal oxygen |
| Optiflow Preoxygenation | End Tidal Oxygen Concentration (ETO2) Following Tidal Volume Breathing Using Either Face Mask or OptiFlow | 87.4 Percentage units of end-tidal oxygen |
Secondary
End Tidal Oxygen Concentration (ETO2) Following Vital Capacity Breaths Using Either Face Mask or OptiFlow
Concentration of oxygen at the end of a breath following 8 deep breaths using either face mask or OptiFlow
Time frame: From baseline ETO2 concentration to the end of 8 vital capacity breaths (approximately 3 minutes)
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Standard Face Mask Preoxygenation | End Tidal Oxygen Concentration (ETO2) Following Vital Capacity Breaths Using Either Face Mask or OptiFlow | 91.8 Percentage units |
| Optiflow Preoxygenation | End Tidal Oxygen Concentration (ETO2) Following Vital Capacity Breaths Using Either Face Mask or OptiFlow | 85.9 Percentage units |