None listed
Conditions
Brief summary
This is a feasibility study for a larger definitive trial, the ‘THRIVER’ study. The specific objective of the THRIVER study is to answer the following research question: is the routine use of THRIVE for preoxygenation more reliable than current conventional approaches in real world clinical practice? The purpose of routine pre-oxygenation is to maximize the amount of oxygen stored in the lungs is to provide an increased margin of safety if a ‘can’t intubate can’t oxygenate’ (CICO) situation arises. The conventional approach is to pre-oxygenate the patient to maximize the amount of oxygen stored in the lungs by having them breathe 100% oxygen from the anesthetic circuit using a sealing oro-nasal mask. THRIVE pre-oxygenates the patient and also provides ongoing oxygenation during laryngoscopy up to the time an airway is secured with an endotracheal tube or a laryngeal mask. Therefore, the operational definition of the term ‘preoxygenation’ in this protocol includes all oxygen given until either the airway is secured or a patent airway is lost. In a CICO situation, the airway is typically lost, so the key issue determining the time to desaturation is the quantity of stored oxygen in the lungs at the moment this happens. CICO situations are potentially lethal, but rare, so showing a reduction in mortality associated with this problem is not feasible in a prospective two-group trial. We therefore plan to address this question in the definitive trial through two indirect indicators of the adequacy of oxygenation during the peri-induction period: 1) The incidence of episodes of desaturation which occur in the peri-induction period*. Adequate oxygen stores in the lung should prevent desaturation from occurring provided adequate cardiac output is maintained, so any episode of desaturation reflects a failure to maintain adequate stores of oxygen at that moment in time (with the same caveat). 2) End tidal oxygen fraction (FETO2) immediately after an airway has been secured with an endotracheal tube or supraglottic airway. During conventional preoxygenation, a FETO2 > 87% is used as an endpoint, but this may drop during laryngoscopy. With THRIVE, FETO2 cannot readily be measured while preoxygenation is occurring. If 100% oxygen is used for the first few minutes after an airway has been secured, FETO2 should provide a good indication of the success or otherwise of preoxygenation up to that point in time – which is what matters clinically.
Interventions
Fisher & Paykel’s Optiflow Trademark uses modified nasal catheters to deliver humidified warm oxygen to patients at high flow (e.g. 70 l per minute). Humidity makes the treatment tolerable. This device has been used in millions of patients in many countries in various clinical settings, including intensive care units and in pediatrics. The value of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) in supporting oxygenation in the context of certain types of respiratory failu
Fisher & Paykel’s Optiflow Trademark uses modified nasal catheters to deliver humidified warm oxygen to patients at high flow (e.g. 70 l per minute). Humidity makes the treatment tolerable. This device has been used in millions of patients in many countries in various clinical settings, including intensive care units and in pediatrics. The value of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) in supporting oxygenation in the context of certain types of respiratory failure has been demonstrated. It is generally comfortable to use and few risks over conventional methods of non-invasive oxygenation have been described. Anesthetists or anesthesia technicians will fit the Optiflow Trademark nasal prongs to the patient upon arrival in the operating room (OR) after the acquisition of an initial arterial oxygen saturation (SpO2) reading (or soon thereafter), with flows set to 40 l/min (or as appropriate, 100% oxygen). After induction the flow will be increased to 70 l/min (or as appropriate). THRIVE will be used up until a secure airway has been established to the satisfaction of the anesthetist, after which it will be switched off. If the airway needs to be replaced within 15 minutes, THRIVE will be switched on again for this purpose. We will ask anesthetists to administer 100% oxygen for at least five minutes following intubation (to standardize this across patients for the detection of the fraction end tidal oxygen (FETO2) readings immediately following intubation). At all times anesthetists will be asked to make the safe care of their patients their primary concern, and to modify the use of THRIVE as they see fit to that end. They will be asked to document deviations from the protocol and reasons for the deviation, in the anesthetic record.
Sponsors
The University of Auckland
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
10 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. aged 10 years or older 2. having elective surgery under general anesthesia with intravenous induction in the study ORs with a participating anesthetist 3. planned use of an endotracheal tube or a supraglottic airway device. 4. scheduled start of anesthesia during working hours 5. willing to provide informed consent
Exclusion criteria
1. Known contraindication to Optiflow Trademark device 2. Undergoing an operation on the acute list for which they have not been appropriately fasted 3. More than 50% (as judged by the anesthetist) of the nares occluded by the nasal prongs 4. Bleeding in nose or oropharynx 5. Situations in which continuous positive airway pressure (CPAP) is contraindicated 6. Pre-existing nasal obstruction 7. Pre-existing hypoxemia
Outcome results
None listed