Hypoxia
Conditions
Keywords
Apneic oxygenation, Apneic diffusion oxygenation
Brief summary
The purpose of the study is to evaluate the effectiveness of continuous oxygen provided by nasal prongs in preventing or delaying hypoxemia during the apneic period that occurs after induction of general anesthesia. This will be evaluated by measuring the arterial oxygen tension (PaO2). The study will also evaluate whether there is any difference in PaO2 when using nasal prongs with flow rates of 5 L/minute versus 10 L/minute of oxygen.
Detailed description
Certain patient populations are at risk for rapid desaturation and the rapid development of hypoxemia (eg. morbidly obese and pregnant patients). Using pulse oximetry, it has already been shown that oxygen provided with a catheter inserted into the nasopharynx is effective in delaying the desaturation that occurs with apnea before the trachea is intubated. It has also been shown that apneic oxygenation with nasal prongs at 5 L/min during fibreoptic intubation can delay the onset of hypoxemia. The study will evaluate whether there is any significant difference in the PaO2 (arterial oxygen tension, as measured by an arterial blood gas) when nasal prongs are used to provide apneic oxygenation in paralyzed patients at flows of 5 L/min compared to 10 L/min. The study aims to demonstrate that apneic oxygenation using nasal prongs is effective in preventing or delaying hypoxemia (by measuring PaO2), and that this technique may be used to prevent morbidity and mortality in all clinical areas (not only in the Operating Room environment) where airway management is undertaken.
Interventions
OTHERNasal oxygen therapy
Arm 1: Nasal cannulae with no oxygen flow. Arm 2: Nasal cannulae with oxygen flow at 5 L/min Arm 3: Nasal cannulae with oxygen flow at 10 L/min
Sponsors
University of Manitoba
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Caregiver)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
1. Healthy males and females 2. ASA Class 1-3 3. Ages of 18 to 65 4. Elective surgery under general anesthesia 5. No evidence of significant cardiac, respiratory or gastrointestinal disease 6. No contraindications to the insertion of a radial arterial catheter
Exclusion criteria
1. Evidence of a difficult airway (expected difficult intubation identified from patient history or clinical examination) 2. Features suggestive of difficult bag mask ventilation 3. Significant GERD requiring medical therapy 4. Significant respiratory disease (including severe asthma or COPD, oxygen dependency, pulmonary hypertension) 5. Significant cardiac disease (ischemic heart disease, severe aortic and mitral stenosis and/or regurgitation, EF \< 50% if known) 6. Inability to lie flat (skeletal deformities, orthopnea, congestive cardiac failure) 7. PaO2 \< 200 mmHg on ABG after adequate preoxygenation to an ETO2 \> 85% 8. Hemoglobin \< 100 g/L 9. BMI \> 40 kg/ m2 10. Pregnancy 11. Patient unwillingness or refusal to participate 12. Inability to consent (dementia) or cooperate (mentally challenged) 13. Inability to communicate well or to understand English (language barrier, dysphasia) 14. Neuromuscular disorders 15. Known or presumed cervical spine instability (cervical spine fractures, rheumatoid arthritis) 16. Patients undergoing neurosurgical procedures 17. Any clinical or radiological evidence of increase in intracranial pressure 18. Any requirement for rapid sequence intubation 19. Inability to tolerate the apneic period 20. Allergy to any of the agents used for induction of general anesthesia in the study 21. Arterial insufficiency with poor collateral circulation to the hand (tested with Doppler ultrasound or clinically by palpation with the Allen test) 22. Inability to cannulate an artery for monitoring and sampling purposes 23. Uncorrected coagulopathy 24. Baseline hypercarbia (PaCO2 \> 50 mmHg) 25. Known or suspected obstructive sleep apnea 26. Significant nasal obstruction
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| PaO2 in mmHg (arterial oxygen tension as measured by an arterial blood gas) | Arterial blood gases taken at one minute intervals post induction in the apneic period, for a total of 4 measurements |
Countries
Canada
Outcome results
None listed