Chapter 15 1. All potential PAP titration candidates should receive adequate PAP education, hands-on demonstration, careful mask fitting, and acclimatization before titration. 2. CPAP (IPAP and EPAP for patients on BPAP) should be increased until the following obstructive respiratory events are eliminated (no specific order) or the recommended maximum CPAP (IPAP for patients on BPAP) is reached: apneas, hypopneas, respiratory effort–related arousals (RERAs), oxygen desaturations, and snoring. 3. The recommended minimum starting CPAP should be 4 cm H2O for pediatric and adult patients, and the recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively, for pediatric and adult patients on BPAP. 4. The recommended maximum CPAP should be 15 cm H2O (or recommended maximum IPAP of 20 cm H2O if on BPAP) for patients younger than 12 years, and maximum CPAP of 20 cm H2O (or recommended maximum IPAP of 30 cm H2O if on BPAP) for patients 12 years or older. 5. The recommended minimum IPAP-EPAP differential is 4 cm H2O, and the recommended maximum IPAP-EPAP differential is 10 cm H2O. 6. CPAP (IPAP or EPAP for patients on BPAP depending on the type of event) should be increased by at least 1 cm H2O with an interval no shorter than 5 minutes, with the goal of eliminating obstructive respiratory events. 7. CPAP (IPAP and EPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least one obstructive apnea is observed for patients younger than 12 years, or if at least two obstructive apneas are observed for patients 12 years or older. 8. CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least one hypopnea is observed for patients younger than 12 years, or if at least three hypopneas are observed for patients 12 years or older. 9. CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least three RERAs are observed for patients younger than 12 years, or if at least five RERAs are observed for patients 12 years or older. 10. CPAP (IPAP for patients on BPAP) may be increased from any CPAP (or IPAP) level, if at least 1 minute of loud or unambiguous snoring is observed for patients younger than 12 years, or if at least 3 minutes of loud or unambiguous snoring is observed for patients 12 years or older. 11. The titration algorithm for split-night CPAP or BPAP titration studies should be identical to that of full-night CPAP or BPAP titration studies, respectively. 12. If the patient is uncomfortable or intolerant of high pressures on CPAP, the patient may be tried on BPAP. If there are continued obstructive respiratory events at 15 cm H2O of CPAP during the titration study, the patient may be switched to BPAP. 13. The pressure of CPAP or BPAP selected for patient use following the titration study should reflect control of the patient’s obstructive respiration by a low (preferably <5/hr) respiratory disturbance index (RDI) at the selected pressure, a minimum sea level oxygen saturation measured by pulse oximetry (SpO2) above 90% at the pressure, and with a leak within acceptable parameters at the pressure. 14. An optimal titration reduces RDI to less than 5 for at least a 15- minute duration and should include supine rapid eye movement (REM) sleep at the selected pressure that is not continually interrupted by spontaneous arousals or awakenings. 15. A good titration reduces RDI to 10 or less or by 50% if the baseline RDI is less than 15 and should include supine REM sleep that is not continually interrupted by spontaneous arousals or awakenings at the selected pressure. 16. An adequate titration does not reduce the RDI to 10 or less but reduces the RDI by 75% from baseline (especially in severe OSA patients), or is one in which the titration grading criteria for optimal or good are met with the exception that supine REM sleep did not occur at the selected pressure. 17. An unacceptable titration is one that does not meet any one of the above grades. 18. A repeat PAP titration study should be considered if the initial titration does not achieve a grade of optimal or good and, if it is a split-night PSG study, it fails to meet AASM criteria (i.e., titration duration should be longer than 3 hours). 1. The indications, goals of treatment, and side effects of NPPV treatment should be discussed in detail with the patient before the NPPV titration study. 2. Careful mask fitting and a period of acclimatization to low pressure before the titration should be included as part of the NPPV protocol. 3. NPPV titration with PSG is the recommended method to determine an effective level of nocturnal ventilatory support in patients with CAH. In circumstances in which NPPV treatment is initiated and adjusted empirically in the outpatient setting based on clinical judgment, a PSG should be used if possible to confirm that the final NPPV settings are effective or to make adjustments as necessary. 4. NPPV treatment goals should be individualized but typically include prevention of worsening of hypoventilation during sleep, improvement in sleep quality, relief of nocturnal dyspnea, and providing respiratory muscle rest. 5. When OSA coexists with CAH, pressure settings for treatment of OSA may be determined during attended NPPV titration PSG following AASM Clinical Guidelines for the Manual Titration of Positive Airway Pressure in Patients with Obstructive Sleep Apnea. 6. Attended NPPV titration with PSG is the recommended method to identify optimal treatment pressure settings for patients with the obesity hypoventilation syndrome, CAH caused by restrictive chest wall disease, and acquired or central CAH syndromes in whom NPPV treatment is indicated. 7. Attended NPPV titration with PSG allows definitive identification of an adequate level of ventilatory support for patients with neuromuscular disease in whom NPPV treatment is planned. 1. The NPPV device used for titration should have the capability of operating in the spontaneous, ST, and timed mode. 2. The airflow, tidal volume, leak, and delivered pressure signals from the NPPV device should be monitored and recorded if possible. The airflow signal should be used to detect apnea and hypopnea, whereas the tidal volume signal and respiratory rate are used to assess ventilation. 3. Transcutaneous or end-tidal partial pressure of carbon dioxide (PCO2) may be used to adjust NPPV settings if adequately calibrated and ideally validated with arterial blood gas testing. 4. An adequate assortment of masks (nasal, oral, and oronasal) in both adult and pediatric sizes (if children are being titrated), a source of supplemental oxygen, and heated humidification should be available. 1. The recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively. 2. The recommended maximum IPAP should be 30 cm H2O for patients 12 years or older and 20 cm H2O for patients younger than 12 years. 3. The recommended minimum and maximum levels of PS are 4 cm H2O and 20 cm H2O, respectively. 4. The minimum and maximum incremental changes in PS should be 1 and 2 cm H2O, respectively. 1. IPAP and EPAP should be increased as described in the AASM “Clinical Guidelines for the Manual Titration of Positive Airway Pressure in Patients With Obstructive Sleep Apnea” until the following obstructive respiratory events are eliminated (no specific order): apneas, hypopneas, RERAs, oxygen (O2) desaturation, and snoring. 2. The PS should be increased every 5 minutes if the tidal volume is low (<6 to 8 mL/kg) 3. The PS should be increased if the arterial PCO2 remains 10 mm Hg or more above the PCO2 goal at the current settings for 10 minutes or more. An acceptable goal for PCO is a value less than or equal to the awake PCO2. 4. The PS may be increased if respiratory muscle rest has not been achieved by NPPV treatment at the current settings for 10 minutes or more. 5. The PS may be increased if the SpO2 remains below 90% for 5 minutes or more and tidal volume is low (<6 to 8 mL/kg). 1. A backup rate (i.e., ST mode) should be used in all patients with central hypoventilation, those with a significant number of central apneas or an inappropriately low respiratory rate, and those who unreliably trigger IPAP/EPAP cycles because of muscle weakness. 2. The ST mode may be used if adequate ventilation or adequate respiratory muscle rest is not achieved with the maximum (or maximum tolerated) PS in the spontaneous mode. 3. The starting backup rate should be equal to or slightly less than the spontaneous sleeping respiratory rate (minimum of 10 breaths/min). 4. The backup rate should be increased in increments of 1 to 2 breaths/min every 10 minutes if the desired goal of the backup rate has not been attained. 5. The IPAP time (inspiratory time) should be set based on the respiratory rate to provide an IPAP time between 30% and 40% of the cycle time (60/respiratory rate in breaths per minute). 6. If the ST mode is not successful at meeting titration goals, then the timed mode can be tried. 1. Supplemental oxygen may be added in patients with an awake SpO2 that is less than 88% or when the PS and respiratory rate have been optimized but the SpO2 remains less than 90% for 5 minutes or more. 2. The minimum starting supplemental oxygen rate should be 1 L/min and increased in increments of 1 L/min about every 5 minutes until an adequate SpO2 is attained (>90%). 1. If the patient awakens and complains that the IPAP, EPAP or both is too high, pressure should be lowered to a level comfortable enough to allow return to sleep. 2. NPPV device parameters (when available) such as pressure relief, rise time, and maximum and minimum IPAP durations should be adjusted for patient comfort and to optimize synchrony between the patient and the NPPV device. 3. During the NPPV titration, mask refit or adjustment or change in mask type should be performed whenever any significant unintentional leak is observed or the patient complains of mask discomfort. If mouth leak is present and is causing significant symptoms (e.g., arousals), use of an oronasal mask or chin strap may be tried. Chin straps are frequently ineffective. One caution with the use of an oronasal mask is that if it is too tight, the jaw can be pushed back and thus worsen obstruction. Heated humidification should be added if the patient complains of dryness or significant nasal congestion or can be used as the default approach; current positive pressure devices offer advanced humidity control and heated tubing to reduce condensation. An important clinical challenge is the recognition of strong effects of the respiratory chemoreflex on sleep breathing outside central apneas and classic periodic breathing/Cheyne-Stokes pattern. Table 15.1 offers practical tips. Often the dynamic pattern rather than individual events need to be assessed. In its simplest form, non-REM (NREM)-dominant obstructive sleep apnea with short-cycle (≤30 seconds) event cycle length associated with oximetry banding suggests strong chemoreflex influences. The REM versus NREM differences may be the most important differentiator. Table 15.1 Recognition of Strong Chemoreflex Modulation of Sleep Breathing 1. Late recognition of the lack or inadequate efficacy of CPAP. 2. Inadequate EPAP—this is a “fatal error” (100% failure is expected). Besides the fact that apneas cannot be eliminated by increase in IPAP alone, expiratory airway instability in general is a more recently recognized and clinically important phenomenon. 3. Inadequate (typically <3 to 4 cm) IPAP-EPAP difference, especially if hypoventilation is the main indication (the closer, the more like CPAP it is). 4. Trying to use a fixed “formula” for titration. 5. Simultaneously increasing IPAP and EPAP, especially if this is done repeatedly across the whole night. 6. Not recognizing significant degrees of mouth leak. 7. Inadequate humidification with resultant increase in nasal resistance. 8. Worsening of inspiratory airflow caused by possible glottic narrowing while using the timed mode; hypocapnia is usually associated. 9. Too high a starting pressure (always taking off from the “end” of CPAP) 1. It is best to increase pressure in increments of 1 cm H2O. With experience, it will be possible to judge when greater increases are required at the individual steps (e.g., IPAP increases for hypoventilation). 2. It is typical to raise either the IPAP or the EPAP and not both (beyond that required to maintain an IPAP-EPAP difference 3 to 4 cm H2O). For example, moving from 10/6 to 11/7 is reasonable, not 10/6 to 13/7. 3. It can be more difficult to recognize hypopneas and flow limitation while on BPAP (compared to CPAP), but use all data you have (arousals, snoring, pressure, effort channels). 4. Do not increase IPAP more than 20 cm H2O (even if available on some of the newer machines) without consulting the physician or technical backup, unless requested in the order. Inadequate control at high pressures is rarely fixed by just more pressure. 5. The final IPAP will usually be at least close to (or even higher than) the CPAP required (if known) to eliminate most, if not all, hypopneas and flow limitation. The ideal end point of titration is to normalize sleep, prevent desaturations and overt airflow obstructions (apneas, hypopneas), and eliminate flow limitation. 6. There is increasing experimental and clinical (human) evidence that expiratory airway narrowing is an important component of upper airway pathophysiology in patients with obstructive sleep-disordered breathing. Real-time video recording of the upper airway and pressure profile measurements have often shown narrowing of the airway to be maximal (or very close to that) in end-expiration. This can vary from patient to patient. What this means in a practical sense is that if EPAP is inadequate, it may be manifested as inspiratory flow limitation or otherwise unstable breathing and arousals. If reasonable IPAP increases (IPAP-EPAP difference of 4 to 5) do not seem to be improving the polysomnographic patterns, increase the EPAP. 7. It is a common error not to choose an adequate EPAP when switching to BPAP from CPAP. Technicians may fall into a pattern of using a “standard” starting BPAP levels, such as 8/5. This can be completely inappropriate if the pressure requirements are higher, and this is best judged based on response to previous CPAP. Use guidelines and examples given later. 8. It is advantageous to simultaneously monitor pneumotachograph (independent inline or PAP machine) flow and the pressure-time profile (mask pressure). The information obtained is complementary, and the implications of the patterns of the pressure profile are well described in the mechanical ventilation literature (e.g., inadequate triggering, overlap of neural expiration and machine inspiration). 9. In is advisable to accurately identify the inspiratory signal early, such as during biocalibrations (this may not be as easy as it may seem once the study is running). A good intercostal electromyogram is useful in this discrimination but may not be available, especially in overweight individuals. The inspiratory part of the curve is usually of lesser duration. Have this part of the flow profile above the baseline, because it is easier, from a visuospatial basis, to appreciate flow limitation (like a “slice cut from the top of a mountain”). With a good pressure trace, flattening and “wobbling” during inspiratory flow limitation, somewhat similar to that seen during CPAP, should be visible. 10. The upper airway may be more unstable on BPAP than on CPAP in individual patients. This phenomenon is characterized by the requirement of an EPAP of very close to or greater than CPAP required to normalize flow, repetitive obstructive apneas in spite of increasing EPAP, and generally increased arousals or patient’s perceived discomfort. 11. The newer bilevel ventilators have settings that can be manipulated to increase patient comfort, especially in those with obstructive and restrictive lung disease. The process does have a trial-and-error component. For example, “wide cycle sensitivity” is the breath detection sensitivity in Philips Respironics BiPAP devices to cycle down to EPAP; there are five cycle sensitivities, at 50%, 35%, 25%, 15%, and 8% of peak flows. The “wide trigger sensitivity” is the breath detection sensitivity to initiate IPAP; there are five trigger sensitivities, at 2.4, 4, 6, 10, and 15 L/min. ResMed has an “easy breathe” shark fin–like profile of inspiratory flow that is more comfortable while awake and perhaps during sleep.
Positive Pressure Titration
Overview
Major Recommendations for Positive Airway Pressure Titration
General Recommendations for Noninvasive Positive Pressure Ventilation Titration
Recommendations for Noninvasive Positive Pressure Ventilation Titration Equipment
Recommendations for Limits of Inspiratory Positive Airway Pressure, Expiratory Positive Airway Pressure, and Pressure Support Settings
Recommendations for Adjustment of Inspiratory Positive Airway Pressure, Expiratory Positive Airway Pressure, and Pressure Support
Recommendations for Use and Adjustment of the Backup Rate/Respiratory Rate
Recommendations Concerning Supplemental Oxygen
Recommendations to Improve Patient Comfort and Synchrony Between the Patient and the Noninvasive Positive Pressure Ventilation Device
Recognition of Strong Chemoreflex Influences on Sleep Respiration
Polysomnographic Characteristic
Relatively Pure Obstructive Sleep Apnea
Chemoreflex-Modulated Sleep Apnea
Obstructive apneas
Dominant.
Less common.
Central apneas
Rare.
Dominant form.
Progressive flow limitation
Typical; long variable-length segments of limited breaths are typical.
Unusual in purest form (e.g., in classic Cheyne-Stokes respiration), but quite common otherwise.
Periodic breathing/Cheyne-Stokes pattern
Rare; may be seen at sleep onset or around sleep-wake transitions.
Typical.
Relative severity in unstable-NREM versus REM sleep
Greater severity in REM sleep.
Minimal severity in REM sleep; this may be best evident during CPAP titrations.
Break point during titration (induction of complex apnea before elimination of flow limitation)
Rare.
Typical.
Respiratory event cycle durations
Variable.
Short cycle (25-35 seconds) is highly suggestive, but long cycle forms also occur.
Respiratory event symmetry in unstable/CAP-NREM sleep including a mirror-imaging pattern of events
Minimal symmetry.
Very symmetrical, and mirror imaging is typical (one half of an event is the mirror image of the other).
Effort signal morphology
Maintained during obstructed breath.
Complete or partial loss between recovery breaths clusters. This contributes to the “concordant waxing and waning of flow and effort” feature that is at the core of recognizing central hypopneas/periodic breathing pattern.
Flow-effort relationships
Discordant: flow is reduced disproportionately to reduction in effort signals.
Concordant: flow and effort follow each other in amplitude.
Arousal timing
Early part of event termination, often first recovery breath related.
“Crests” event, often in the center of a sequence of recovery breaths that progressively increase and decrease in amplitude.
Oxygen desaturation profile
Irregular, progressive drops, sharp contour.
Smooth, symmetrical, progressive drops rare. Rarely < 80%.
Nonadaptive bilevel PAP–induced instability
Less common, usually with clearly excessive pressure support only.
Typical.
Common Errors During Bilevel Titration
Bilevel Ventilation Practice Points
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Motor Disorders During Sleep
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