Preoxygenating with noninvasive ventilation (NIV)

Noninvasive ventilation (NIV) has an excellent track record when used for chronic obstructive pulmonary disease (COPD) and pulmonary edema; yet it has limited success with other diseases, such as pneumonia, acute respiratory distress syndrome (ARDS), and asthma. But, as you may guess, every patient responds differently to treatment with NIV. And patients that do not improve on NIV, may need endotracheal intubation and invasive mechanical ventilation.

When NIV should not be used

Noninvasive ventilation should not be used for preoxygenation before routine intubations. In situations like elective surgeries or procedures, a nonrebreather mask (NRB) or a bag-valve-mask (BVM) is typically used.

When NIV should be used

When patients who require endotracheal intubation have hypoxia despite the use of greater than 6 L / min of oxygen, delivered via nasal cannula, consider the use of NIV as a tool for preoxygenation. These patients have a much higher risk of developing low oxygen levels during the process of intubation, compared with patients who are not on oxygen. In these cases, NIV is the preferable preoxygenation choice.

Using NIV for preoxygenation will allow for longer periods of normal oxygen levels during apnea—once the patient is sedated, the NIV mask will need to be removed to perform laryngoscopy and insertion of the endotracheal tube.

NIV versus NRB

Using NIV in patients prior to intubation can optimize their oxygen saturation and blood oxygen content. NIV can deliver a set pressure and fraction of inspired oxygen (F_IO₂) to patients through the mask interface, neither of which is possible with an NRB. The NIV mask is placed so that it is tight-fitting and minimizes leakage. Compared to the NRB mask, this delivery of positive pressure can improve preoxygenation by allowing a higher F_IO₂ to be delivered to the patient.

NIV versus BVM

Noninvasive ventilation also improves preoxygenation when compared with a BVM. Rather than using manual application of the BVM to the face, the NIV mask interface can be optimally positioned to deliver oxygenated gas with minimal leakage around the mask. The NIV ventilator can deliver inspiratory and expiratory pressures at a set F_IO₂.

Typical settings for preoxygenation using NIV are pressure support (PS) of 10 cmH₂O, positive end-expiratory pressure (PEEP) of 5 cmH₂O, and the fraction of inspired oxygen (F_IO₂) at 100%.

The goal is to get the patient’s oxygen saturation as high as possible. If they continue to have oxygen saturation < 95%, consider increasing your positive end-expiratory pressure, or PEEP, to 8 or 10 cmH₂O, as tolerated by the patient.

Time is precious during attempts at intubation! You don’t want to have a situation where the patient’s oxygen levels are dropping before the endotracheal tube is inserted. Preoxygenation with NIV gives you more time to successfully complete the intubation procedure, avoiding the possibility of deadly complications.

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