Titration of Continuous Positive Airway Pressure and Bilevel Positive Airway Pressure

Cheryl Thomas-Yvanauskas

Harry Whitmore

Richard S. Rosenberg

No procedure is more challenging for the sleep technologist than positive airway pressure (PAP) titration. Although challenging, PAP titration is also the most potentially rewarding procedure that the technologist will perform in the sleep center. An adequate PAP titration can dramatically improve the health and quality of life for the patient. The technologist must use social skills to prepare the patient for titration and reduce his or her fears. The technologist interacts with the patient to ensure that a proper mask is chosen and is appropriately fit for comfort. Once the titration begins, the technologist must recognize sleep stages, arousals, and sleep-related breathing events “on the fly” to determine when to increase the pressure to normalize respiration. As changes to the pressure level are made, the technologist must evaluate patient response. All of this must occur within the patient’s sleep period, which may be shortened by patient anxiety, resulting in prolonged sleep-onset latency or awakenings.

Most sleep centers have a “split-night” protocol in which the first half of the night is used to make or confirm a diagnosis of obstructive sleep apnea (OSA), and the second half of the night is available for PAP titration. This requires the sleep technologist to closely monitor the patient’s sleep and respiratory patterns as well as body position and accomplish the goals of PAP titration in a limited time. Split-night studies are not recommended for pediatric patients less than 12 years of age.

The American Academy of Sleep Medicine (AASM) has provided guidelines for the titration process (1). These guidelines were developed through literature review and consensus. One important conclusion of this review was that appropriate pressure cannot be determined using mathematical models that use height, weight, neck size, airway size, or other measures. The only approved way to determine the pressure needed to normalize breathing is to monitor respiration during a titration study. The primary goal of PAP titration is to eliminate obstructive respiratory events including apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring. A secondary goal of PAP titration is to improve the patient’s sleep architecture. There is a window of acceptable pressures for most patients, rather than one absolutely correct pressure. Pressure that is too low will not treat the patient’s respiratory events, and pressure that is too high may cause arousals and central respiratory events. These challenges require the sleep technologist to find an optimal pressure level that normalizes breathing without disrupting sleep.

From the moment the patient enters the sleep center, the technologist begins building a rapport with the patient to ensure a positive experience during PAP titration. A positive initial experience with PAP therapy has been
shown to predict future adherence to the treatment (2). Even the best treatment is useless if the patient doesn’t use it. The initial impression of the patient to PAP therapy is an essential factor in treatment adherence. The technologist should work to find the best PAP platform for each patient (within the bounds of the sleep center’s policies and procedures) and the most comfortable mask and headgear, and if necessary provide heated humidification. Ideally, the titration study provides all the information needed to guide the physician in prescribing the most appropriate treatment for each patient.

Regular meetings between the technologist, the interpreting physician, and the sleep center team provide an opportunity to discuss cases and challenges in determining when to perform a split-night study and address issues that do occur during PAP titrations. The decision to perform a split-night procedure is usually outlined in the sleep center policy manual.

To determine a final pressure for the patient, detailed technologist notes are of utmost importance during PAP titration studies. The technologist is expected to explain why PAP was started, which is typically based on an estimate of the patient’s apnea-hypopnea index (AHI). The technologist should always document changes in PAP and the reasons that changes were made. In addition, it is sometimes helpful to note why changes were not made. The technologist may be giving the patient a few minutes to adjust to a change in pressure or waiting to see if sleep-onset central apneas will resolve. A brief note will let the interpreting physician know that the technologist is aware of all aspects of the situations that occur during the titration study and provide insight into the decisions that were made.

PREPARING THE PATIENT FOR PAP TITRATION

Let’s take a look at a split-night study scenario. Put yourself in the patient’s shoes (or slippers) for a moment. It is 1 a.m. and you have been sleeping soundly in the sleep center. The lights go on suddenly and Bob, the sleep technologist, is at the bedside. He mumbles something about starting treatment. You have no idea what he means. He looks at your face, says “Medium Wide,” and begins rummaging in a closet. He pulls out a plastic bag with a contraption inside, connects it to a vacuum cleaner hose, connects the hose to a machine on the bedside table, and tells you to sit up. Looming over you, he presses a plastic mask onto your nose and starts wrapping straps around your head. Can you expect a successful titration? I think not.

Most patients undergoing full-night titrations will have reviewed their diagnostic study with the sleep physician and had a discussion about PAP therapy. Receiving a diagnosis of OSA can cause anxiety, and patients may not remember what they were told in the office. There should be a copy of the diagnostic report in the patient’s chart, which the technologist can review with the patient and answer questions the patient might have. The discussion should include an explanation of why PAP is important, device options, and a review of the masks that are available in your sleep center.

When a split-night study has been ordered, the technologist should review the patient’s chart thoroughly before their hookup. The AASM recommends that all potential PAP titration candidates receive adequate PAP education, hands-on demonstration, careful mask fitting, and acclimation before titration (1). Surprises may be OK for birthday parties, but they should be avoided whenever possible in the sleep center. The technologist should inform the patient that if the protocol for a split-night study is met, the technologist will come in during the night to initiate PAP.

ANTICIPATING PATIENT CONCERNS

It is best to introduce a patient to PAP therapy before the night of titration in the sleep center. An education session should include a discussion of the rationale for the use of PAP therapy, side effects, mask fitting, and a hands-on demonstration with acclimatization; this is of particular importance for pediatric patients. However, because of time and reimbursement issues, this is not always possible. The technologist may be providing the first introduction the patient has about the PAP device; if this is the case, the technologist should be as complete as possible and allow plenty of time for questions. It may not be clear what a patient is feeling, and for the titration to be successful, you must maintain a positive, “can do” attitude. Explain that the device uses room air and contains a fan that speeds up to produce increased air pressure when the airway is obstructed. Let the patient know that you will be controlling the pressure from another room. Describe the mask options that are available. Reassure the patient that the mask is clean or new and that procedures are in place to reduce infection. One approach to patient education is:

If possible, allow the patient to watch a video that follows a patient through diagnosis and treatment.
Show the patient the equipment and describe how it works.
Let the patient handle the equipment and the mask. Have the patient hold the PAP mask in place (at the lowest pressure of 4 cm H₂O) without strapping the mask on. Allow the patient to practice breathing through the mask until he or she feels comfortable (a minimum of 2 to 3 minutes). Next, have the patient try PAP with the straps holding
the mask in place. Demonstrate how to release the headgear in the event the patient panics and needs to remove the mask quickly. Allow the patient to remove the mask.
Explain that he or she will be exhaling against the PAP. Explain that a nasal mask works best with the mouth closed, and that when the patient opens his or her mouth, the air will rush out, making it difficult to talk. Slowly raise the pressure to between 8 and 10 cm H₂O in order to demonstrate a higher level of pressure to the patient.

The most common question encountered before PAP titration is “How will I sleep with that on my face?” Telling the patient “almost everyone sleeps” is often not enough. It is more helpful to address the patient’s concerns directly. Ask if the patient is concerned about the mask, the pressure, or the newness of the situation. Patients often ask about going to the bathroom during the night, waking with the mask off, feelings of suffocation, and noise. Some technologists provide answers to these questions even before they are asked. It is also helpful to explain that you will be adjusting the pressure throughout the night with the goal of eliminating the patient’s respiratory events. Explain that upon awakening the pressure may feel different from when they fell asleep. Similarly, it is important to be open about the fact that the patient may still have breathing problems during the titration night, as the technologist needs to see respiratory events before increasing PAP. Reviewing this information with the patient before lights out can be beneficial and reduce the patient’s apprehension. It is not uncommon for patients to have difficulty falling asleep with PAP in place for the first time.

If it is clear that a patient is tense or anxious, it may be necessary to let the patient take a break from PAP for a brief time and sit up for a while, instead of having him or her continue to try to sleep. By having the patient sit quietly, he or she is likely to calm down and relax, thus increasing the chance that the patient will be able to continue with the PAP titration and be able to sleep. While the patient is sitting up, the technologist can work with the patient to practice using PAP again. The technologist should reduce the pressure before reapplying the mask.

For patients who awaken during the night and have difficulty tolerating PAP while awake, reduce the PAP until the patient returns to sleep. Most PAP devices that the patient will have at home will have a ramp feature to allow him or her to lower the pressure and return to sleep after awakening during the night. Once the patient is asleep, gradually increase to the pressure titrated before the awakening and continue the titration.

With experience, technologists develop techniques and skills to respond to patient concerns and reassure patients in order to get an optimal titration.

Adjustment of PAP

During a full-night titration, adjustment of pressure begins at lights out. For split-night titrations, the sleep center policy and procedures manual should define the criteria that must be met before beginning titration. The AASM practice parameters (3, 4) recommend titration guidelines, but do not set a standard for when to begin the titration portion of a split-night study. The basic recommendation is that PAP titration should be started if an AHI higher than 40 is documented during 2 hours of a diagnostic study. Titration may be considered for an AHI between 20 and 40 on the basis of the clinical judgment of the ordering physician. Because this is a recommendation and not a standard, some centers use different thresholds for initiation of a split-night titration. Some sleep centers set thresholds for the AHI that will cover PAP device reimbursement by Medicare. At the time of this writing, the Medicare requirement is an AHI of 15 or an AHI of 5 or more with associated clinical symptoms such as high blood pressure and daytime sleepiness. Sleep centers should have a policy that delineates the cutoff time for starting a split-night titration. In AASM-accredited centers, the medical director is required to provide clear and detailed instructions for all procedures, including PAP titration, in a Policy and Procedures manual.

Recognizing Inadequate Titration

The core concept of PAP titration is simple: increase the pressure until the goals of titration are met (Fig. 48-1). The primary goal of PAP titration is the elimination of obstructive respiratory events, including apneas, hypopneas, RERAs, and snoring. A secondary goal of PAP titration is to improve the patient’s sleep architecture.

Inadequate pressure is defined by the AASM guidelines (1) as two or more obstructive apneas, three or more hypopneas, five or more RERAs, or 3 or more minutes of loud snoring in adults. Scoring of these respiratory events during titration is somewhat different than
during the diagnostic portion of the study because the oronasal thermal sensor and the nasal pressure transducer are typically replaced by a flow measure output from the PAP machine. Scoring of both apneas and hypopneas is therefore based on the PAP device flow signal. According to the AASM scoring manual (5), score a respiratory event as an apnea when there is a drop in the peak signal excursion by 90% or more of the preevent baseline and the duration of the 90% or more drop in flow signal is 10 seconds or more. Two rules for scoring of hypopnea are provided:

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