Positive Airway Pressure for Obstructive Sleep Apnea (OSA)

1. Positive Airway Pressure For OSAS BYAHMAD YOUNESPROFESSOR OF THORACIC MEDICINE Mansoura Faculty Of Medicine

2. International classification of sleep disorders, criteria for OSA: Diagnosis = A + B + D or C + D A. At least one of the following applies: i. Complaints of unintentional sleep episodes during wakefulness, daytime sleepiness, un-refreshing sleep , fatigue, or insomnia. ii. Awakenings with breath-holding, gasping, or choking. iii. Bed partner reports loud snoring and/or breathing interruptions during the patient’s sleep. B. Polysomnography shows the following: i. Scoreable respiratory events (apneas + hypopneas + RERAs)/hr of sleep ≥ 5/hr. ii. Evidence of respiratory effort during all or a portion of each respiratory event.

3. International classification of sleep disorders, criteria for OSA: Diagnosis = A + B + D or C + D C. Polysomnography shows the following: i. Scoreable respiratory events (apneas + hypopneas + RERAs)/hr of sleep ≥ 15/hr. ii. Evidence of respiratory effort during all or a portion of each respiratory event. D. The disorder is not better explained by: another current sleep disorder, medical or neurologic disorder, medication use, or substance use disorder.

4. Positive Airway Pressure Therapy • Administration of positive airway pressure therapy is the treatment of choice for most patients with OSA. • CPAP treatment is generally recommended for all patients with an AHI greater than or equal to 15/hour and for symptomatic patients (eg, excessive daytime sleepiness, insomnia, impaired cognition, mood disorder, hypertension, ischemic heart disease, or stroke) with an AHI between 5–15/hour.

5. Treatment modalities for Positive Airway Pressure Therapy • Continuous positive airway pressure Provides a constant pressure throughout the respiratory cycle • Bi-level positive airway pressure Provides two pressure levels during the respiratory cycle: a higher level during inspiration and a lower pressure during expiration • Autotitrating positive airway pressure Provides variable pressures using device-specific diagnostic and therapeutic algorithms • Nocturnal noninvasive positive pressure ventilation Provides two pressure levels at a set rate to assist ventilation

6. Determining Optimal Continuous Positive Airway Pressure 1. In-laboratory attended polysomnographically guided CPAP titration • Full-night studies. • Split-night studies (consists of an initial diagnostic portion and a subsequent CPAP titration on the same night) 2. Unattended laboratory or home titration 3. Use of autotitrating devices 4. Formula-derived pressures from clinical, PSG, and/or anthropometric variables

7. The current standard of practice • The current standard of practice involves an attended pressure titration during a laboratory PSG, during which sleep stages and respiratory variables are monitored. • The goal is to determine a single fixed pressure that eliminates apneas, hypopneas, snoring, and respiratory effort–related arousals (RERAs); maintains adequate oxygen saturation; and improves sleep architecture and quality in all sleep positions and in all sleep stages. • It is generally accepted that higher pressures are required to reverse airway occlusion during REM sleep and during sleep in a supine position. • Spit-night studies can potentially underestimate the severity of OSA

11. Criteria for split-night (CPAP) titration • At least 2 hours of recorded sleep time during the initial diagnostic portion of the study • Apnea-hypopnea indices during the diagnostic portion of the study: AHI 40 OR • AHI 20–40 (accompanied by significant oxygen desaturation) • At least 3 hours are available for CPAP titration with the presence of REM sleep during a supine sleep position

13. AASM recommendations for CPAP and BPAP therapy for adult patients with sleep related breathing disorders • The presence of OSA based on an acceptable diagnostic method should be established prior to CPAP therapy (standard). Indications for CPAP therapy include: a. Moderate to severe OSA (standard) b. Mild OSA (option) c. Improvement of subjective sleepiness in patients with OSA (standard) d. Improvement of quality of life in patients with OSA (option) e. As an adjunctive therapy to lower blood pressure in patients with OSA (option)

14. AASM recommendations for CPAP and BPAP therapy for adult patients with sleep related breathing disorders 3. The preferred CPAP titration method to determine optimal positive airway pressure is an in-laboratory, full-night, attended polysomnography, but split-night studies are usually adequate (guideline). 4. Objective monitoring of CPAP use is recommended to ensure optimal utilization (standard). 5. Close monitoring of CPAP utilization and any problems that might develop, especially during the first few weeks of use, is important, as is the correction of problems if needed (standard). 6. Addition of heated humidification and a systematic educational program enhance adherence to CPAP use (standard).

15. AASM recommendations for CPAP and BPAP therapy for adult patients with sleep related breathing disorders 7. Patients with OSA treated with CPAP therapy should be followed up yearly or more frequently as needed to correct problems related to its use (option). 8. CPAP and bilevel positive airway pressure (BPAP) therapy are generally safe with minor adverse effects (standard). 9. BPAP can be considered as an optional therapy to CPAP in selected patients who require high pressures, who report difficulty exhaling against a fixed CPAP pressure, or who have coexisting central hypoventilation (guideline). 10. BPAP may also be beneficial in patients with some forms of restrictive lung disease or hypoventilation syndromes with daytime hypercapnia (option).

16. AASM recommendations for CPAP and BPAP therapy for adult patients with sleep related breathing disorders • The extent to which asymptomatic patients with mild OSA and no associated medical or psychiatric disorders benefit from CPAP is less certain. • Intermittent use of CPAP should be avoided, because virtually all of the gains in sleep quality and daytime alertness derived from sleeping with CPAP are rapidly reversed with CPAP discontinuation.

18. Beneficial effects of positive airway pressure therapy in OSA • Sleep quality Improvement in sleep quality • Upper airway anatomy and function • Reduction or elimination of snoring • Decrease in apneahypopnea index (AHI) • Increase in arterial oxygen saturation (SaO2) • Sleepiness and other daytime symptoms • Decrease in sleepiness (subjective and objective) • Improvement in quality of life • Enhancement of mood and neurocognitive function

19. Beneficial effects of positive airway pressure therapy in OSA • Hypertension Improvement in blood pressure and heart rate profiles in patients with hypertension • Congestive heart failure Improvement in cardiac function in patients with OSA • Health care utilization Reduction in physician claims and hospital stay • Mortality Reversal of the increase in mortality associated with sleep apnea

20. Adverse consequences of positive airway pressure therapy • Aerophagia and gastric distention • Arousals , Sleep disruption due to noise from the device • Barotrauma (eg, pneumothorax, pneumomediastinum, pneumocephalus) • Chest discomfort and tightness • Claustrophobia, sensation of suffocation or difficulty with exhalation • Eye irritation (conjunctivitis) • Facial skin irritation, rash or abrasion • Mask and mouth leaks • Nasal congestion, dryness, epistaxis or rhinorrhea • Sinus discomfort or pain

21. Adherence to Positive Airway Pressure Therapy • Therapeutic adherence in the different studies has varied from 46% to 80% of patients who use CPAP for 4 or more hours nightly on at least 70% of monitored nights. • Self-reports often over estimate actual CPAP use. • Approximately 50% of patients are consistent CPAP users, and the rest are intermittent users with a wide range of nightly use. • Average nightly use is between 4 to 5 hours each night among CPAP users. The percent of days in which CPAP was not used correlated with decreased duration of nightly use.

22. Factors influencing long-term use • Factors influencing long-term use include snoring history, severity of illness (AHI), perceived benefit from therapy, and self-reported sleepiness (Epworth Sleepiness Scale [ESS]. • Patients with mild OSA have a particularly high rate of CPAP discontinuation. • Long-term use of CPAP does not appear to be related to the prescribed pressure. Finally, CPAP usage tends to be greater among patients who underwent full-night CPAP titration studies compared to those who had split-night CPAP titration.

23. Factors influencing long-term use • Patterns of nightly use are often discernible by the first few days or weeks of initiating treatment. • Adherence to CPAP therapy may be improved with education (eg, additional home visits , participation in group clinics, periodic phone calls to uncover any problems and to encourage use, and even simple written information on the importance of regular CPAP use), airway humidification, proper selection of the CPAP interface, desensitization procedures for CPAP, early follow-up , prompt and aggressive management of adverse effects related to CPAP use, and regular assessment of CPAP adherence.

24. Reasons for non-adherence to positive airway pressure therapy 1-Perception of lack of benefit: Patient education 2-Discomfort with its use (including mask): Mask refitting (nasal masks, nasal pillows, full-face masks, ororal masks) 3-Noise from the device Placing device in another room adjacent to bedroom ,Use of ear plugs or noise-attenuating devices 4-Air leaks from the mask or mouth: Mask refitting for mask leaks , Use of chin strap or full face mask for mouth leaks 5-Airway humidification , Treatment of nasal congestion 6-Difficulty with exhaling against high expiratory pressures Trial of CPAP with C-flex technology or bilevel positive airway pressure (BPAP) 7-Excessively high pressures: Trial of automated positive airway pressure or Adjunctive therapy with sleep position treatment or oral devices

25. Reasons for non-adherence to positive airway pressure therapy 8-Frequent nocturnal awakenings: Brief trial of hypnotic agents during the acclimatization phase of initial CPAP use (eszopiclone) 9-Claustrophobia:Mask refitting (eg, nasal pillows or oral masks),Formal program of CPAP desensitization 10-Nasal problems: • Dryness:-Airway humidification (preferably heated) Use of nasal lubricants • Sneezing ,Congestion , Rhinorrhea :-, decongestants, anticholinergic agents, or corticosteroids , oral decongestants, Immunotherapy, or antihistamine agents • Epistaxis:- Nasal surgery (in patients with nasal anatomic abnormalities) 11-Gastric distention due to aerophagia BPAP therapy

26. Automatic CPAP For OSAS

27. Auto-positive airway pressure • Auto-positive airway pressure (APAP) devices provide a useful alternative for providing positive airway pressure (PAP) treatment for patients with obstructive sleep apnea (OSA) . • One can separate the uses of these devices into two large categories These include: • Auto-titration PAP to determine an effective fixed level of continuous positive airway pressure (CPAP) • Auto-adjusting PAP for chronic treatment.

28. Auto-positive airway pressure devices • When used in the auto-titration mode, the devices are used by the patient for a period of time (one night to several weeks). Information stored in the device is transferred to a computer and can be used to select an optimal fixed level of CPAP for chronic treatment. • When APAP devices are used for chronic treatment they have the potential advantage of delivering the lowest effective pressure in any circumstance (body position, sleep stage). The mean pressure for the night may be lower than a single pressure that would be effective in all circumstances (the prescription pressure). For example, higher CPAP is usually needed in the supine posture and during rapid eye movement (REM) sleep.

29. Auto-titrating mode • Attended auto-titration in CPAP naïve patient (technologist extender) • Unattended auto-titration in CPAP naïve patient • Check prescription pressure after weight gain/loss • Salvage a failed manual CPAP titration Auto-adjusting mode • Initial chronic treatment of OSA (no titration needed) • Chronic treatment in patients not tolerating CPAP • Chronic treatment in patients with difficult mask/mouth leak

30. DEVICE CHARACTERISTICS • The devices differ in the respiratory variables that are monitored and in the algorithms used to adjust the delivered pressure. • The devices typically monitor one or more of the following:airflow (or motor speed), airflow profile (flattening), snoring (airway vibration), or airway impedance (forced oscillation technique). • The algorithms used to adjust pressure are proprietary but determine if the delivered pressure should be increased or decreased. • Depending on the type of respiratory event that is detected the delivered pressure is increased by a certain amount.

31. Open unrestricted airway

32. Silent partial airway obstruction

33. Noisy partial airway obstruction

34. Complete airway obstruction

35. Open unrestricted airway

36. DEVICE CHARACTERISTICS • The S9 Series detects both obstructive and central sleep apneas (CSA). CSA detection uses the Forced Oscillation Technique (FOT) to determine the state of the patient’s airway during an apnea. • When an apnea has been detected, small oscillations in pressure (1 cm H2O peak-to-peak at 4 Hz) are added to the current device pressure. The CSA algorithm uses the resulting flow and pressure (determined at the mask) to measure the airway patency.

37. An APAP device using this technology does not increase pressure for “clear airway” apneas.

38. DEVICE CHARACTERISTICS • Typically, pressure changes occur slowly over several minutes to prevent pressure-induced arousals. • If no respiratory events are detected within a certain time window the delivered pressure is slowly decreased. Thus, the lowest effective pressure is delivered. • In some of the devices machine adjustment is available for various mask types and for the type of humidifier that is being used. • Studies comparing different APAP devices provide evidence that devices from different manufacturers will not deliver the same pressure for a given clinical circumstance .

40. DEVICE CHARACTERISTICS • The responses of several devices differs markedly in response to apnea. Some of the devices increased the delivered pressure in response to apnea while others did not . • Comparing the 95th percentile pressure of one APAP device based on airflow to another based on the forced oscillation technique found poor agreement between the optimal pressure identified by the two devices. • The adherence and clinical outcomes were similar although the median applied pressure was slightly higher with the device that responded to airflow limitation .Thus, differences in the devices do not always translate into differences in outcomes.

41. Problems of APAP algorithms • The problems of mask/mouth leak and central apnea have provided a challenge for the designers of APAP algorithms. • Mask/mouth leaks tend to raise the baseline flow delivered by blower units and diminish the variations in flow during inspiration and expiration. The resulting airflow signal may be interpreted as an apnea or hypopnea and prompt an increase in pressure that may further increase leak. • To handle the leak problem many APAP units have algorithms that limit pressure increases when leak exceeds certain values or when increases in blower speed no longer result in increases in mask pressure. Other units have leak alarms that can prompt the patient to adjust the mask.

42. Problems of APAP algorithms • Mouth leaks can be approached by using a chin strap or full-face mask. • Algorithms often include limits on upward titration of pressure for apnea to avoid the delivery of high pressure for central apneas. For example, pressure is not increased above 10 cm H2O unless apnea is associated with snoring or airflow profile flattening.

43. Expiratory pressure relief • Expiratory pressure relief (C-Flex, Respironics) is now available for one brand of APAP devices. • This mode allows a reduction in pressure during early expiration with a return to the current set pressure at end expiration. • This feature could improve patient tolerance to pressure.

46. Automatic adjustment of bi-level PAP • APAP machines providing automatic adjustment of bilevel PAP (BPAP) are available. These devices vary inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP) according to a proprietary algorithm. • The physician sets the minimum EPAP, maximum IPAP, and maximum IPAP–EPAP difference. • The option of using inspiratory and expiratory pressure relief (Bi-Flex R, Respironics) is currently available for one device brand. • Inspiratory pressure relief allows a drop in pressure at end inhalation (IPAP) while expiratory pressure relief allows a pressure drop at the start of exhalation (EPAP).

47. A single night profile showing changes in IPAP and EPAP over the night with auto-bilevel positive airway pressure.

48. Manual PAP titration is labor intensive and usually a single technologist can titrate only two patients at a time. • Patients in some geographical areas may have limited or delayed access to a sleep laboratory offering polysomnography. • In addition, the gold standard PAP titration method may result in suboptimal titrations due to a number of problems including poor sleep, lack of supine REM sleep, high mask leak, or uncorrected mouth leak. Patient characteristics such as weight gain may also render previously selected pressures inadequate. • Auto-titrating PAP devices can be used to address some of these problems.

49. AUTO-TITRATION • One important use of APAP devices is selection of a fixed CPAP pressure as an alternative to traditional manual (attended) PAP titration . • Information stored in the device memory can be analyzed and a pressure can be chosen for fixed CPAP treatment. • A common method is to choose the 90th or 95th percentile pressure (pressure exceeded only 10% or 5% of the time, respectively) as the prescription pressure. This assumes periods of high leak have been eliminated from the analysis.

50. Efficacy of Auto-Titration • Unattended APAP was successful at identifying an effective CPAP level. • Treatment with fixed CPAP using a pressure identified by unattended APAP titration reduced the AHI to < 10/hour in 38/40 subjects. • In 15 of 20 patients the difference between the APAP pressure (taken as P95) and the CPAP chosen by manual titration was equal to or less than 1 cm H2O.