The Ups and Downs of Bi-level Pressure Therapy in Sleep
Transcription
The Ups and Downs of Bi-level Pressure Therapy in Sleep
The Ups and Downs of Bi-level Pressure Therapy in Sleep disordered breathing Shahid M. Ahsan, M.D. Pulmonary Medicine Critical Care Medicine Sleep Disorder Medicine Sigma Medical Group Sleep Apnea Sleep Apnea refers to the temporary absence or cessation of breathing (airflow) during sleep. Traditionally defined as 10 seconds for adults and eight seconds (or more than two times the normal respiratory cycle time) in infants. Obstructive apnea: ventilatory effort but no airflow Central apnea: no effort to breathing Mixed apnea: no ventilatory effort, but an obstructive apnea pattern is evident when effort resumes Complex Sleep Apnea have a mixture of both OSA and CSA Apnea Patterns Obstructive Airflow Respiratory effort Mixed Central Sleep Apnea Hypopnea: arbitrary decrease in airflow signal in conjunction with arbitrary reduction in oxygenation saturation measured by pulse oximetry Apnea-Hypopnea index (also called respiratory disturbance index or disordered breathing event index), which is number of apneas plus hypopnea per hour of sleep Upper Airway resistance Syndrome: A mild variant of obstructive sleep disordered breathing Patients present with complaints of excessive daytime sleepiness, polysomnography reveals loud snoring associated with respiratory effort related arousals Guilleminault C, Sleep 1994;17:242-7 Medicare CPAP rules • A single level continuous positive airway pressure (CPAP) device is covered if the patient has a diagnosis of obstructive sleep apnea (OSA) documented by an attended, facility-based polysomnogram and meets either of the following criteria (1 or 2): 1) The AHI is greater than or equal to 15 events per hour (Moderate OSA) ; or • 2) The AHI is from 5 to 14 events per hour (Mild OSA) with documented symptoms of: a) Excessive daytime sleepiness, impaired cognition, mood disorders, or insomnia; or, b) Hypertension, ischemic heart disease, or history of stroke. OSA vs. Central vs. Complex OSA starts with airway collapse CSR : Pulmonary congestion/chemoreceptors/ circulation Obstructive Sleep Apnea Symptoms ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾ Snoring Excessive daytime sleepiness or Insomnia Fatigue Morning headaches History of witnessed apneas Complaints of impotence History of High Blood Pressure History of Depression Pathophysiology of Apnea Exam: Oropharynx Exam: Tonsillar Hypertrophy Shepard JW Jr et al. Mayo Clin Proc 1990;65. Obstructive Sleep apnea Mechanisms Negative Negative oropharyngeal oropharyngeal Pressure Pressure Primary events Sleep Apnea Decreased DecreasedUpper UpperAirway Airway Muscle Activity Muscle Activity Small SmallPharyngeal PharyngealCavity Cavity High Pharyngeal Compliance High Pharyngeal Compliance High HighUpstream UpstreamResistance Resistance Apnea Baseline arterial PO2 Degree of Diffuse Airways Obstruction Lung Volume O2, CO2 pH Chemoreceptor Sensitivity CNS Arousability Arousal From Sleep Resumption of Airflow Return to Sleep Sleep Apnea Apnea ↓O2, ↑CO2, ↓ pH Arousal from Sleep Resumption of Airflow Decreased Pleural Pressure Increased Cardiac Afterload Left Heart Failure Vagal Bradycardia Ectopic Cardiac Beats Unexplained Nocturnal Death, Stroke Pulmonary Vasoconstriction Pulmonary Hypertension Right heart failure Systemic Vasoconstriction Systemic Hypertension Acute CO2 Retention Chronic Hypoventilation Cerebral Dysfunction Loss Of Deep Sleep Sleep Fragmentation Return to Sleep Excessive Motor Activity Excessive Daytime Sleepiness Intellectual Deterioration Personality Changes Behavioral Disorders Restless Sleep OSA and splinting of airway by CPAP Obstructed Airway Patent Airway CPAP Masks Positive Airway Pressure: Problems Positive Airway Pressure Mask: Complications Mean percentage days CPAP used CPAP Compliance Time CPAP used Kribbs NB et al. Am Rev Respir Dis 1993;147. CPAP Compliance • Patient report: 75% • Objectively measured use > 4 hrs for > 5 nights / week: 46% • Asthma-medicine compliance: 30% Mask fit is critical • • • • Patients won’t use it unless it’s comfortable Most manufacturers have a fitting guide – make a point of using it Many patients will need a chin strap to prevent air leakage from the mouth Poor fit can result in: 1. Air leaks, leading to increased flow rates as the CPAP machine tries to compensate 2. Damage to skin because straps are too tight Positive Airway Pressure Machines Positive Airway Pressure Devices • Continuous positive airway pressure (CPAP) 1.Positive end expiratory pressure (PEEP) or Continuous end expiratory pressure (CPAP), acts as a pneumatic splint to prevent collapse of the pharyngeal airway 2. Maintains a constant level of pressure throughout the patient’s respiratory cycle during spontaneous breathing 3. Pressure range 4 to 25 cm water 4. Effective both in obstructive apneas and mixed apnea 5. Some central apneas are associated upper airway resistance, so may help Continuous Positive Airway Pressure (CPAP) 6. Simple apnea prevention is not the endpoint of CPAP titration 7. Residual upper airway obstruction may present as arousal only, so objective should be try eliminate arousals 8. When correct CPAP pressure is reached the sleep should no longer be fragmented by repetitive arousals and in fact rebound slow wave sleep and rapid eye movements REM sleep 9. Continued snoring is another sign of inadequate CPAP pressure, so objective should be to eliminate snoring during CPAP titration Bilevel Positive Airway Pressure (BiPAP) 1. Provides air at suitable pressures and flow rates for patient ventilation assistance 2. Assistance is provided by administration of two levels of positive pressure 3. During exhalation, pressure is variably positive or near ambient, Expiratory Positive Airway pressure (EPAP), range 4-25 cm water 4. Inspiratory level is variably positive and is always higher than expiratory level, Inspiratory Positive Airway pressure (IPAP), range 4-30 cm of water Bilevel Positive Airway Pressure (BiPAP) 5. Responds precisely to changes in patient flow rates which indicates movement to inhalation and exhalation 6. Reliably sense the patient’s breathing efforts to trigger the change inspiratory effort 7. BiPAP spontaneous/timed (S/T) senses air flow in patients circuit by using flow transducer, If the patient fails to initiate an inspiration, the unit will cycle to Inspiratory PAP (IPAP) preset interval determined by synchronized rate breaths per minute (BPM) Bilevel Positive Airway Pressure (BiPAP) Respironics® BiPAP® M Series with Bi-Flex® Sleep Systems ¾BiPAP Auto combines auto adjusting bi-level pressure delivery with the breath-by-breath pressure relief of Bi-Flex ¾Bi-Flex technology “softens” the airflow in inhalation and exhalation to provide increased pressure relief, making breathing more comfortable for the patient. Digital Auto-Trak™ Sensitivity works with Bi-Flex and the auto algorithm to track each breath so that the device can cycle between inspiratory and expiratory pressure based on the patient’s breathing. The result is more natural and comfortable therapy. Auto-titrating Continuous positive airway pressure (Auto CPAP) ¾ Auto-PAP is the machine that has a system with diagnostic capability of recognizing obstructive respiratory events ¾ Parameters monitored by various systems include those derived from airflow, pressure or snoring and other airway sounds (e.g: airway vibration) ¾ Data suggest that severe OSAS can be accurately identified by this machine Auto-titrating Continuous positive airway pressure (Auto CPAP) It has not been established that unattended automatic CPAP titration is safe without previous diagnostic polysomnogram to establish the diagnosis of OSA Other nocturnal breathing disorders like central sleep apnea, chronic hypoventilation due to emphysema or other diseases cannot be recognized with automatic CPAP Patients are at risk for mask leak which may lead to increased variability of CPAP pressures and associated arousals The amount of pressure required for effective CPAP therapy varies according to sleep stage, sleep position, and other factors. Insufficient pressure results in ineffective therapy while too much pressure can lead to discomfort, non-compliance, and pressure-related side effects. ResMed’s AutoSet SpiritTM is an automatic titration system for the treatment of obstructive sleep apnea (OSA). AutoSet devices adjust pressure on a breath-by-breath basis to suit patient needs as they vary throughout the night. As a result, the patient receives the minimum pressure required for effective therapy. The lower pressures may improve patient comfort, reduce pressure-related side effects, and lead to increased patient compliance. The AutoSet algorithm responds to three key respiratory parameters: Inspiratory flow limitation Snore Apnea REMstar|pro 2 by Respironics ¾The REMstar|pro 2 with C-Flex is an advanced, patient friendly CPAP system. It is Encore Smart Card stores all the data for exceptionally quiet and easy for patients to use. It is packed with features that help accommodate the needs of all types of patients. The downloading by your physician. Now you don't have to take your machine with you. ¾The REMstar|pro 2 delivers a wide pressure range to fill the need of most patients. It is also tolerant for most mask leaks. It provides an effective, comfortable form of therapy. REM Star C-flex CPAP machine by Respironics C-Flex positive airway pressure • A complaint by those using conventional CPAP is that it is difficult to breath out against the pressure • C-Flex is designed to provide pressure relief during exhalation • C-Flex technology reduces expiratory pressure in response to airflow, the relief pressure varies on a breath to breath basis - depending on the actual patient flow • 90% of a study participants believed that C-Flex was a very comfortable ¾VPAP™ Adapt SV is an adaptive-servo ventilator designed specifically to treat central sleep apnea (CSA) in all its forms, including complex and mixed sleep apnea. ¾Unlike conventional SDB therapies such as CPAP, adaptiveservo ventilation: ¾Treats complex sleep apnea syndrome and central sleep apnea ¾Normalizes breathing, completely suppressing CSA and/or Cheyne-Stokes respiration (CSR) ¾Improves sleep architecture (the amount of time the patient spends in slow-wave and REM sleep increases). ResMed S8 Escape ¾Small, lightweight 2.9 pounds, robust, and travelfriendly. ¾* 12VDC and 24VDC power input via ResMed's 12 VDC converter and automatic international power switching. ¾* Flexibile user management capabilities incluing the ResScan Data Card that interacts with ResMed's PCbased user management system. The adaptive-servo ventilation algorithm: Adapts to the patient’s ventilatory needs on a breath-by-breath basis automatically calculates a target ventilation (90% of the patient's recent average ventilation) adjusts the pressure support to achieve it. Maximizing patient comfort and compliance VPAP Adapt SV: Ensures pressure support is synchronized to the patient's own recent breathing rate and flow pattern provides a constant, low level of pressure support. Strategies to Improve Compliance • Machine-patient interfaces – Masks – Nasal pillows – Chin straps • • • • Humidifiers Ramp Desensitization Bi-level pressure Comfort Series Nasal Mask by Respironics RESPIRONICS Comfort Lite 2 ComfortLite 2 uses its new "Halo" headgear and forehead mechanism for stability. This allows the cushion to provide a comfortable, reliable seal with no pressure points -- and that's why we put special focus on the cushion The ComfortLite 2 reaches an all new level of personalized comfort with three cushion styles available: Pillows Cushion, Simple Cushion and Direct Seal Cushion Nasal Aire II nasal CPAP prong The Mirage Swift nasal pillows system provides Mirage comfort and quality in a nasal pillows system. It's ideal for people who want a light, flexible system that provides a clear field of vision. ComforGel mask by Respironics ResMed Mirage Activa Mirage Activa -- the first nasal mask with ActiveCell Technology Active Seal---dynamic seal and leak control during active sleep, all night long. Auto-stabilizing --- air-filled suspension keeps the cushion in place, even when various forces pull or push the mask frame in different directions. ResMed Mirage Activa Improved comfort --- due to reduced headgear strap tension. Easier fitting --- due to less dependence on headgear trap tension. ActiveCell Technology maintains an active seal and a dynamic defense against leaks. Fisher and Paykel Flexifit 405 mask ¾The Hybrid is a unique fusion of technologies, designed to be a universal interface for patients, clinicians, providers and users. This one product serves as a nasal interface, an oral interface, and a combination of the two. ¾The Hybrid is a dual airway interface for use with positive pressure ventilation devices for the treatment of respiratory insufficiencies and obstructive sleep apnea. The unique design of the Hybrid promotes patient comfort by eliminating pressure points on the forehead and across the bridge of the nose. The Mirage Kidsta™ Nasal Mask by ResMed Fisher and Paykel The FlexiFit 431 Full Face Mask with Under Chin Design builds on the foundation of the unique features common to the FlexiFit Series of nasal masks. The FlexiFit Technology has been incorporated into the contoured Silicone Seal to allow a large range of nasal bridge movement and simple one step auto adjustment fitting. The unique Glider Strap provides freedom of movement while maintaining a seal. Complex Sleep Apnea Characteristics Characteristics of Complex Sleep Apnea Complex Sleep Apnea is a mixture of OSA which converts over to central apnea upon CPAP application and opening of the airway 1 Minimal data available 1 Typically emerges during titration not during diagnostic PSG Emerges with the implementation of CPAP to alleviate OSA events1 Occurs at ~ 30 second intervals vs. 60-90 second intervals with CSR Estimated prevalence 1/7 or ~15% of the SDB population Morganthaler, et. al. Sleep 2006; 29 (9):1203-1209 CompSAS: OSAHS and CSA Complex Sleep Apnea Syndrome: The 3 main forms of Central Sleep Apnea are: Idiopathic Central Sleep Apnea, Complex Sleep Apnea or CheyneStokes Respiration, or Periodic Breathing. Patients considered to have complex sleep apnea syndrome if CPAP titration eliminated events defining obstructive sleep apnea-hypopnea syndrome, but residual central sleep apnea index was more than 5 or more per hour or Cheyne-Stokes respiratory pattern became prominent and disruptive Morgenthaler TI, et al, Sleep 2006; 29: 1099-1248 RAD policy requirements for Central or Complex Sleep Apnea Defines when a BiPAP® S/T (E0471) can be prescribed for a specific patient population Definition of Complex Sleep Apnea (form of central sleep apnea) Persistence or emergence of central events upon exposure to CPAP/BiPAP S when obstructive events have disappeared Complex patients have predominately obstructive or mixed apneas during the diagnostic sleep study occurring at > 5 events / hour With the application of CPAP / BiPAP S, patterns of apnea and hypopnea that meet the definition of CSA What is Complex Sleep Apnea? It is central apnea that emerges after the application of CPAP for OSA Idiopathic Central Sleep Apnea – Under PSG •No output from respiratory center of the brain causing lack of movement of the thorax. •No movement of thorax & abdomen causes apnea Treatment Recommendations for Idiopathic Central Apnea Oxygen Therapy ** Oxygen Therapy and CPAP Therapy Must have desaturation below 88% for 5 minutes or longer to qualify for oxygen therapy (CMS guidelines) OR 89% for 5 minutes with history of either CHF, Pulm. HTN, Cor Pulmonale or Increased RBC count Must have desaturation + AHI >5 with EDS or AHI>15 without EDS (CMS guidelines) Medications: Theophylline 1, 3 Acetazolamide 2, 3 Gradual reduction of opioid medications may improve narcotic-induced CSA3 1 Orth, et al. Resp. Med. 2005;99:471-476 2 Javahari, S. AJRCCM: 2006:173(2) 234-237 3 Eckert, et al. Chest. 2007; 131:595-607 Remember: <2% of SDB Diagnosis of Central Sleep Apnea Defines when a BiPAP® S/T (E0471) can be prescribed for a specific patient population CANNOT BE STRAIGHT OSA, MUST HAVE FORM OF CSA Central Sleep Apnea Apnea index > 5 Central apneas / hypopneas >50% of the total apneas / hypopneas Central apneas or hypopneas > 5 times per hour Recommendations for Implementation of S/T Titration Titration done in the sleep lab setting or home environment for COPD, neuromuscular abnormality, or restrictive disease. Recommended starting points: Start on S/T Mode EPAP 4 cmH20 IPAP 8 cmH20 Rate of 8-10 bpm or 2 less than patients’ set RR I-Time: 1.2 seconds Rise time: 2-3 Careful monitoring of sleep parameters and blood gas parameters should occur (including CO2 if available) Titration should occur based on events Monitoring of ventilation should continuously occur to maintain the patients original ventilation levels: Tidal volume (IPAP – EPAP) Patient respiratory rate vs. device rate Assess & titrate ventilation based on Vt, Rate, SaO2 and CO2 compared to baseline Assess Vt: Adequate? Too Small Maintain EPAP ↑ IPAP by 2 Return Yes Titration Protocol for S/T Evaluate for Apnea – OSA Yes ↑ EPAP & IPAP by 1 Maintain ∆ Return No Assess Rate and SaO2 Titration Protocol for S/T Assess and titrate ventilation based on Vt, Rate, SaO2 and CO2 compared to baseline Evaluate back up rate: Is it adequate? No Yes With sleep-related events: raise EPAP and IPAP by 1 SaO2 <90%? With pulmonaryrelated issues: add supplemental O2 1Lpm Raise rate by 2 BPM as needed Assess I-Time for comfort Return Return Titration Protocol for NIV – Prescription Zone Prescription for BiPAP® S/T Mode Breath Per Minute (if in S/T): 0 to 30 breaths/min IPAP setting: 4 to 30 cm of water EPAP setting: 4 to 25 cm of water I-Time : 0.5 to 3.0 seconds Ramp Time: 0 to 45 minutes Humidification : Heated Implementation of autoSV® Titration: Complex Breathing BiPAP® AutoSV® designed for patients who have mixed apneas, complex apnea, periodic breathing or central apnea Recommended starting points: Switch mode to BiPAP® autoSV® EPAP: last pressure that relieved obstructive apnea IPAPmin: same as EPAP IPAPmax: 25-30 cm H20 Rate: 8-10 BPM or 2 below spontaneous RR Rise time: 2-3 I-Time: 1.2 sec Treatment Recommendations NO to CPAP for patients with Central Sleep Apnea and Heart Failure due to CANPAP Results Medical management of heart failure is KEY in treatment for resolving CSR 1 This includes alterations in medications used to treat heart failure If the patient has predominately OSA (<50% CSA) CPAP can help with improvement of EDS or Sleep Apnea If the patient has predominately Central Apnea (>50%) Oxygen therapy 1 Bi-Level therapy with back up rate 2 Adaptive Servo Ventilation3 1 Javaheri, et. al. Curr Treatment Option in CV Med: 2005:7:295-306 2 Kasi, et. al. Circ. J.; 200569:913-921 3 Teschler et al, AJRCCM, 164:614-419, 2001 Implementation of autoSV® Titration: Periodic Breathing BiPAP® autoSV® is designed for patients who have mixed apneas, complex apnea, periodic breathing or central apnea Recommended starting points: Switch mode to BiPAP® autoSV® EPAP: 4 cm H20 IPAPmin: same as EPAP IPAPmax: 10 cm H20 above IPAPmin Rate: Auto Rise time: 2 or 3 Titration Protocol autoSV®: Periodic Breathing Assess Patient Observe for obstructive apneas Yes Raise EPAP, IPAPmin and IPAPmax by 1 Return No Observe for partial airway obstruction Yes If no leaks and obstructive, raise EPAP by 1 Return No Observe for continued periodic breathing and central apneas not corrected by auto-rate Titration Protocol autoSV®: Periodic Breathing Assess Patient Central apneas not corrected by auto-rate Yes Set fixed rate to minimum of 10 BPM or 2 below starting RR; set I-Time for 1 – 2 sec Return No Observe for periodic breathing Yes Raise IPAPmax by 2 cm H20 Return No Summary of Treatment Strategies for SDB Patients ~5% have CSA or CSR Treatment includes: Medication mgmt. Oxygen therapy Bi-Level therapy ASV therapy OSA CSA ~85% - 90% of patients have OSA Treatment includes: CPAP or BiPAP S Complex ~10% have Complex SDB Treatment includes: CPAP therapy CPAP + Oxygen Bi-Level Therapy ASV o f h e a t e d h u m i d i f i c a t i o n b e i n g p r o v i d e d ¾The HC604 comprises ThermoSmart Technology, a unique Fisher & Paykel Healthcare technology that allows for optimum levels of humidity independent of room temperature. ¾The levels of heated humidification being provided are up to 50% higher than conventinal humidifiers are able to deliver (up to 30 mg/l. Furthurmore, the technology prevents condensation from forming and thus ensures optimal pressure being delivered at the mask. a r e u p t o 5 0 % h i g h e r t h a n c o n v e n t i Humidifiers Heated humidifiers are intended to resolve the symptoms caused by the effects of dry air, cool air temperatures, and pressure, created by CPAP, on the tissue in the nasal passage and upper airway. Those symptoms are usually one or more, but not always, of the following: Nasal congestion, sinus congestion, nasal tissue bleeding, dry throat, dry mouth, excessive dried mucus, and the numerous arousals caused by the foregoing symptoms. Humidifiers Heated humidifiers are effective in resolving the symptoms listed. However, environmental conditions within the sleeping area can severely effect the entire system. Conditions such as placement of the CPAP flow generator, room temperature, the breathing circuit (tubing, mask or nasal pillows/seal) and the length of the air tubing are key factors. Humidifiers Temperature at the ceiling is higher than at the floor. For every foot of height there is about 1 degree temperature increase. If your CPAP is on the floor it will be drawing intake air that is about 3 degrees cooler than the air at your nose level and about 5 degrees cooler than the temperature at the thermostat level. If you sleep in a 65 degree (at thermostat level) bedroom, the temperature on the floor is closer to 60 degrees; nose level about 63 degrees. Remember, air entering your lungs is 98.6 degrees and 100% relative humidity. It is the job of the nasal tissue and the tissue in your upper airway to warm and humidify the ambient air to body conditions. If the air flow is to dry and/or to cool it can cause the symptoms listed previously. Humidifiers We've learned that warm air can hold more water vapor than cool air. We also learned that a lower atmospheric pressure allows more water vapor to form than higher pressure. CPAP and heated humidifiers Applying these two principles to CPAP and heated humidifiers we can reason that the lower the pressure and warmer the water in the heated humidifier chamber, the higher the relative humidity in the air flow. Increasing the pressure increases the air flow rate and has a squeezing effect on water vapor, lowering the relative humidity. In simple terms, if you are on high CPAP pressures you need to run higher temperatures in your heated humidifier. This can lead to rain-out and gurgling in the air tubbing. To increase the relative humidity the temperature of the water in the humidifier must be increased so there is more water vapor available for absorption into the air stream. Humidifiers Secondly, your breathing circuit dissipates heat rapidly. Every part of the mask or nasal pillows, and tubing is made as light weight as possible. When a sufficient amount collects, the air flowing through the tubing, reacting on the collected water, causes a gurgling sound that will wake you. Fisher & Paykel vinyl sleeve Fisher & Paykel vinyl sleeve In order to eliminate condensation in the tubing and to deliver a warm humid air flow to alleviate the symptoms caused by CPAP, the simple solution is to insulate the tubing. Fisher & Paykel offers a vinyl sleeve that goes over the outside of the tubing and is held in place by wide, heavy rubber bands. It forms a dead air space around the tube. Ramp Time Pressure Ramp allows initiation of CPAP at a very low positive pressure (2-4 cm H2O) to higher preset pressure Pressure can build on the preset time period that range from 5 to 45 minutes, allowing the patient to fall asleep before reaching higher levels o prescribed pressure Chin Restraint/Chin Strap: Separate strap to help hold mouth closed during CPAP treatment and reduce air leaking from mouth.