New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

Abstract

Introduction: Tracheal intubation in the intensive care unit (ICU) is associated with severe life-threatening complications including severe hypoxaemia. Preoxygenation before intubation has been recommended in order to decrease such complications. Non-invasive ventilation (NIV)-assisted preoxygenation allows increased oxygen saturation during the intubation procedure, by applying a positive end-expiratory pressure (PEEP) to prevent alveolar derecruitment. However, the NIV mask has to be taken off after preoxygenation to allow the passage of the tube through the mouth. The patient with hypoxaemia does not receive oxygen during this period, at risk of major hypoxaemia. High-flow nasal cannula oxygen therapy (HFNC) has a potential for apnoeic oxygenation during the apnoea period following the preoxygenation with NIV. Whether application of HFNC combined with NIV is more effective at reducing oxygen desaturation during the intubation procedure compared with NIV alone for preoxygenation in patients with hypoxaemia in the ICU with acute respiratory failure remains to be established.

Methods and analysis: The HFNC combined to NIV for decreasing oxygen desaturation during the intubation procedure in patients with hypoxaemia in the ICU (OPTINIV) trial is an investigator-initiated monocentre randomised controlled two-arm trial with assessor-blinded outcome assessment. The OPTINIV trial randomises 50 patients with hypoxaemia requiring orotracheal intubation for acute respiratory failure to receive NIV (pressure support=10, PEEP=5, fractional inspired oxygen (FiO2)=100%) combined with HFNC (flow=60 L/min, FiO2=100%, interventional group) or NIV alone (reference group) for preoxygenation. The primary outcome is lowest oxygen saturation during the intubation procedure. Secondary outcomes are intubation-related complications, quality of preoxygenation and ICU mortality.

Ethics and dissemination: The study project has been approved by the appropriate ethics committee (CPP Sud-Méditerranée). Informed consent is required. If combined application of HFNC and NIV for preoxygenation of patients with hypoxaemia in the ICU proves superior to NIV preoxygenation, its use will become standard practice, thereby decreasing hypoxaemia during the intubation procedure and potential complications related to intubation.

Trial registration number: NCT02530957.

Figure 1

Consort diagram of the OPTINIV trial. ABG, arterial blood gas; FiO₂, fractional inspired oxygen; HFNC, high-flow nasal cannula oxygen therapy; NIV, non-invasive ventilation; PEEP, positive end-expiratory pressure; PS, pressure support.

Figure 2

Study design of the OPTINIV trial. FiO₂, fractional inspired oxygen; HFNC, high-flow nasal cannula oxygen therapy; ICU, intensive care unit; NIV, non-invasive ventilation; PEEP, positive end-expiratory pressure; PS, pressure support.

Figure 3

Blinding sequence of the OPTINIV trial. To allow blinding, a nasal cannula will be positioned in each group. The operator performing the intubation will blind the group by placing a large sheet over the oxygen flow metre. Both groups will receive non-invasive ventilation (NIV). (A) Interventional group: In the interventional group (real high-flow nasal cannula oxygen therapy (HFNC)+NIV), the nasal cannula will be connected to the oxygen flow metre via a tube and oxygen set at 60 L/min and 100% of fractional inspired oxygen (FiO₂) which will be delivered to the patient. In the interventional group, preoxygenation at 30° of head-up inclination with NIV (pressure support (PS) of 10 cm H₂O, positive end-expiratory pressure (PEEP) of 5 cm H₂O, FiO₂=100%) and oxygen HFNC set at 60 L/min and 100% of FiO₂ was applied. (B) Reference group: In the reference group (fake HFNC+NIV), no oxygen flow will be administered by the nasal cannula to the patient. The tube connected to the nasal cannula positioned on the patient will be hidden under the sheet, without connection to the oxygen flow metre. To mimic the noise of HFNC in the reference group, another nasal cannula will be hidden under the sheet and connected to the oxygen flow metre, with a flow also set at 60 L/min. In the reference group, preoxygenation at 30° of head-up inclination with NIV only (PS of 10 cm H₂O, PEEP of 5 cm H₂O, FiO₂=100%) without oxygen HFNC (nasal cannula positioned without any flow) was applied.