None listed
Conditions
Brief summary
NHF therapy has been used in the hospital for patients requiring respiratory support, for over a decade. It can deliver 100% oxygen at flow rates up to 70 l.min-1 through an unsealed, wide-bore nasal interface (“prongs”). These high flows are tolerable due to the gas being humidified. Recently, this technique has been introduced in general anaesthesia to ventilate the patient. A potential limitation of the technique is that it cannot be used simultaneously with bag mask ventilation (BMV), which is the standard care in anaesthetic practice. This is because the anaesthetic mask is unable to be sealed over the nasal cannula and flow from the nasal interface can interfere with both monitoring and BMV. The objective of this study is to evaluate whether a newly designed nasal interface that allows NHF and BMV to be administered interchangeably provides an improvement in the ease-of-use relative to the existing NHF interface and does so at appropriate pressures.
Interventions
This is a prospective, randomised, interventional, crossover pilot study. Participants in this study will receive the conventional treatment once and the interventional treatment once, in a randomised order immediately after anaesthetic induction but prior to the procedure (delivered by the anaesthetist):
o Conventional treatment – Bag mask ventilation (BMV) alone (75 seconds).
o Interventional treatment – BMV with the Switching Interface in place (75 seconds).
The convent
This is a prospective, randomised, interventional, crossover pilot study. Participants in this study will receive the conventional treatment once and the interventional treatment once, in a randomised order immediately after anaesthetic induction but prior to the procedure (delivered by the anaesthetist): o Conventional treatment – Bag mask ventilation (BMV) alone (75 seconds). o Interventional treatment – BMV with the Switching Interface in place (75 seconds). The conventional and interventional treatments are both forms of non-invasive techniques that deliver oxygen. BMV uses a facemask that forms a tight seal over the mouth and nose, whereas, the Switching Interface is an open system that uses prongs to deliver oxygen through the nose. The treatments will be delivered sequentially without a washout period. This study will use an intention to treat analysis, however, any deviations from the protocol will be noted in case report forms by the research coordinator.
Sponsors
Fisher & Paykel Healthcare
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used) (Investigator)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1) Provide written informed consent. 2) Having elective surgery under general anaesthesia with intravenous induction in an operating room with a participating anaesthetist.. 3) BMI must be less than 35 kgm-2.
Exclusion criteria
1) Patients in whom CPAP is contraindicated (e.g. pneumothorax, bullous lung disease, craniofacial trauma, airway, foreign body, unstable haemodynamics) 2) Pre-existing nasal obstruction. 3) Pre-existing hypoxaemia (Oxygen Saturation less than or equal to 89%). 4) Known cyanotic congenital heart disease. 5) Patients undergoing induction with volatile anaesthetics. 6) Patients undergoing caesarean section. 7) Bleeding in the nose or oropharynx. 8) Patients requiring preoperative oxygen therapy secondary to chronic lung disease. 9) Uncontrolled cardiac arrhythmias. 10) Uncontrolled heart failure. 11) Patients with known allergies to anaesthetic agents. 12) Severe hypertension (diastolic blood pressure greater than 120 mmHg). 13) Patients with unstable angina or a recent ( 6 or fewer months) myocardial infarction. 14) Current pulmonary embolism. 15) Symptomatic severe aortic stenosis. 16) Patients in whom a high FiO2 is contradicted (e.g. patients treated with Bleomycin). 17) Patients undergoing procedures with electrocautery or lasers. 18) Patients at risk of aspiration including those who are not fasted or those undergoing rapid sequence induction. 19) Patients where bag mask ventilation is not possible. 20) Patients with oesophageal reflux disease
Outcome results
None listed