Comparison of high flow nasal oxygen vs conventional bag mask ventilation for preoxygenation and apnoeic oxygenation in adults with difficult mask ventilation under general anaesthesia: an open labelled randomised controlled trial
Trial Snapshot
- Phase
- Not Applicable
- Status
- Not yet recruiting
- Sponsor
- Enrollment
- 72
- Locations
- 1
- Primary Endpoint
- The primary objective is to assess the difference in partial pressure of oxygen, after 3 min of preoxygenation in patients preoxygenated with HFNO vs patients preoxygenated with bag mask ventilation
Study Overview
Brief Summary
When anaesthesia is induced, hypoxemia can quickly develop as a result of hypoventilation or apnoea in combination with decreased FRC. Preoxygenation is the process of replacing nitrogen in the lungs with oxygen which will provide an increase in time before hemoglobin desaturation occurs. Preoxygenation is conventionally performed by 3 min of tidal volume breathing of 100% oxygen via bag-mask attached to an anaesthesia machine or a Mapleson circuit. The flow rate of oxygen is kept high enough to prevent rebreathing (10-12L/min). To ensure adequate preoxygenation, no leaks around the mask must be present. After preoxgenation an induction agent, and subsequently a muscle relaxant is administered. During the apnoea period after induction and muscle relaxant administration, the oxygenation is maintained using the continued bag and mask ventilation. Safe apnoea time is typically defined as the time from spontaneous cessation of breathing until the peripheral arterial oxygen concentration (SpO2) falls below 90%. With maximal preoxygenation, the time to oxyhaemoglobin desaturation below 90% can be up to 8 minutes in adults with normal airway and around 3 minutes or less in children and obese adult patients.
Preoxygenation, apnoeic oxygenation by bag-mask ventilation, and consequently intubation without the unwanted event of hypoxemia in adults with difficult bag-mask ventilation can be a challenging task for an anaesthesiologist. Hence, it is the need of the hour to come up with an alternative technique of oxygenation in such subset of patients.
Recent studies have provided evidence of using the High Flow Nasal Oxygen to prolong apnoea time and tool to achieve preoxygenation effectively. High flow nasal oxygen (HFNO) via high flow nasal canula (HFNC) can deliver oxygen at flow rate up to 60L/min with more predictable FIO2 than with other devices and may generate PEEP and increase end-expiratory lung volume (EELV)
Hence this study is conducted to compare High Flow Nasal Oxygen vs conventional bag-mask ventilation for preoxygenation and apnoeic oxygenation in adults with difficult bag-mask ventilation under general anaesthesia. No study has been conducted till now on the adult patient population with difficult bag mask ventilation.
We hypothesize that high flow nasal oxygenation is as effective as the conventional bag-mask ventilation in delivering adequate preoxygenation and apnoeic oxygenation in adults with difficult bag-mask ventilation under general anaesthesia
Study Design
- Study Type
- Interventional
- Allocation
- Computer generated randomization
- Masking
- Open Label
Eligibility Criteria
- Ages
- 18.00 Year(s) to 65.00 Year(s) (—)
- Sex
- All
Inclusion Criteria
- •All ASA I &II aged 18-65 Years posted for general anaesthesia who are anticipated difficult airway comprising of the following a) Patients with BMI >25 b) Absence of teeth c) History of snoring d) Bearded patient e) Mallampati grade III and IV f) Severely limited mandibular protrusion g) Face and neck deformities due to prior surgery, prior trauma, congenital abnormalities h) Previous and current cervical spine injuries i) Patients with rheumatoid arthritis, scleroderma j) Patients with oropharyngeal cancers
- •Consent for participation.
Exclusion Criteria
- •Pregnant females
- •Patients having cardiorespiratory pathologies
- •Patients who are planned for rapid sequence induction.
Outcomes
Primary Outcomes
The primary objective is to assess the difference in partial pressure of oxygen, after 3 min of preoxygenation in patients preoxygenated with HFNO vs patients preoxygenated with bag mask ventilation
Time Frame: The difference in partial pressure of oxygen will be noted by taking arterial blood sample after three minutes of pre oxygenation
Secondary Outcomes
- 7. Reoxygenation time defined as the time taken for SpO2 to return to 100% after mechanical ventilation.(After initiation of Mechanical ventilation)
- 2. Difference in end tidal O2(After intubation)
- 6. Any complications until following intubation like arrhythmias(After intubation)
- 3. Incidence of hypoxemic events(SpO2 92%)(Number of Events until intubation)
- 4. Tolerability of high flow nasal canula by patients, i.e., if patients request to reduce flow or feeling of dryness, itching etc.(Till induction)
- 5.Time taken to successful intubation(After Intubation)
- 1. Difference in partial pressure of oxygen.(After intubation)