Tricks to titrating noninvasive ventilation (NIV)

Previously, you learned tips on initiating noninvasive ventilation (NIV): avoid the use of sedative medications if possible, start with a single low pressure on the ventilator (i.e., continuous positive airway pressure, or CPAP, mode), and allow patients to hold the mask up to their face before tightly attaching the straps.

The real benefit of NIV is achieved when you choose the right mode of ventilation and adjust to the appropriate settings.

In order to get a handle on how to titrate NIV, let’s take a look at how to use NIV in two different patients.

First, let’s take a look at Meryl, a 72-year-old woman with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Choose the right mode

For Meryl, with her AECOPD, we will want to choose bilevel positive airway pressure (BPAP) as our mode of NIV. Delivering two pressures, one during inspiration and one during expiration, will assist with ventilation, offload her respiratory muscles, and improve her airflow obstruction.

Meet the pressure goals

For Meryl to acclimate, we started with a continuous pressure of 2–3 cmH₂O and then titrated up to a pressure of 5 cmH₂O. To provide her with an inspiratory and expiratory pressure, we’ll want to add pressure support (PS) until we see a reduction in respiratory rate. To do this, we’ll increase by 2 cmH₂O every five minutes to end up with a level between 7–10 cmH₂O.

Monitor oxygen saturation

The fraction of inspired oxygen (F_IO₂) can be set anywhere between 21% and 100% to meet the saturation goals of the patient. For Meryl, we’ll want her oxygen saturation to be greater than 88%, and we’ll titrate the F_IO₂ to that goal.

Now, let's consider Tom, a 67-year-old male with acute respiratory failure, perhaps from acute pulmonary edema.

Choosing the right mode

For Tom, continuous positive airway pressure (CPAP) is the preferred treatment option. Start with a low level of CPAP and increase the pressure by 2 cmH₂O every few minutes. Just like with BPAP, the F_IO₂ can be titrated between 21% and 100% according to the patient’s saturation goals.

Meet the pressure goals

Studies of NIV on patients with pulmonary edema found a positive end-expiratory pressure (PEEP) level of 8–12 cmH₂O provided clinical benefit for most patients.

As you titrate upwards, be mindful of the effects of increased inspiratory pressures.

With high pressures it is easier for the interface to leak, undoing any benefit from the increased pressure. Additionally, there is the risk of gastric insufflation as the pressure of air overcomes the pressure of the lower esophageal sphincter. When inspiratory pressure settings approach 25 cmH₂O, one must consider intubation and invasive mechanical ventilation.

But don’t forget about tidal volume (V_T). Since we are setting pressure and not volume, the V_T will depend on the compliance of the patient’s lungs. High V_T can cause volutrauma to the lungs that may lead to worse outcomes. To reduce this risk, adjust the inspiratory pressure and monitor the measured V_T on the ventilator to achieve between 6 and 8 mL / kg of predicted body weight.

That’s it for now. If you want to improve your understanding of key concepts in medicine and improve your clinical skills, make sure to register for a free trial account, which will give you access to free videos and downloads. We’ll help you make the right decisions for yourself and your patients.