Sleep Study(Polysomnography) By Hatem EzzeldinHassen MD Consultant of Phoniatrics KFHJ
DIAGNOSIS History: Snoring Obstructive episodes Arousals /nocturnal choking Excessive daytime sleepiness Abnormal motor movements Morning headaches Nasal obstruction Weight gain Drugs: alcohol intake Cardiovascular symptoms Respiratory symptoms Thyroid symptoms Social history
Examination General appearance Weight Height Blood pressure Craniofacial morphology Nasal airway Tongue size, Soft palate/uvula/tonsils Nasopharynx - adenoids / polyps / cyst / tumor Hypopharynx-lingual tonsils/vallecula, epiglottic or supra-glottic cysts / tumour Larynx-vocal folds mobility
Investigations: • To assess thepatient's general condition • To differentiate between simple snoring andsleep apnea and determine the presence, type and severity of any apneas or hypopneas and, • To assess the site of airway obstruction obstruction
Investigations • Polysomnography • Lateral cephalometry • Naso-optic fibroscopy(Muller’s maneuver) • Sleep nasendoscopy • Computed tomography (CT) • Magnetic resonance imaging (MRI) • Acoustic reflection technique • Pharyngeal manometry • Acoustic analysis of snoring sounds
*is the gold standard investigation in the diagnosis of OSAS and other forms of sleep related disorders.*multiple simultaneous recording of physiologic measures during sleep. Polysomnography
PHYSIOLOGY OF SLEEP Normal sleep entails a cyclical progression from non rapid eye movement sleep (N-REM) to rapid eye movement sleep (REM) with a periodicity of 90-120 minutes. During N-REM sleep, subjects pass through 4 stages which represent progressively deeper sleep states. During REM sleep, increased movements and EEG activity occurs with characteristic eye movements. Dreaming & Obstructive episodes are likely to occur during REM sleep A normal young adult would spend 5 % of the night in stage 1, 45 % in stage 2, 15 % in stage 3, 10 % in stage 4, and 25 % in REM sleep (Baker, 1986).
Polysomnography • Electroencephalogram (EEG). • Submental electromyogram (EMG). • Electro – oculogram (EOG) : These three measurement are needed for sleep staging and allow differentiation between sleep and wakefulness. • Oxygen saturation (PO2): by Modern pulse oximeters • Electrocardiogram (ECG) : To monitor apnea associated arrhythmias. • Nasal and oral airflow: airflow is usually detected using heat sensitive thermoisters. These are not able to quantify airflow but simply detect its presence or absence. Absence of airflow for greater than 10 sec. Will be counted as an apnea. • Chest and abdominal movement: patients wear an elasticized belt around the chest and abdomen into witch are incorporated strain gauges that measure changes in circumference. This information allows differentiation between central and obstructive apnea. • Anterior tibialis EMG: Allows the diagnosis of “periodic movements during sleep” • Sleeping position detector :
Polysomnography A B A: Central apnea B: Obstructive apnea
Sleep Related Breathing Disorders - Definitions • Snoring:is a noise generated from the upper airway due to partial airway obstruction • An apnea:is the cessation of airflow at the nostrils and mouth for at least 10 seconds. • The apnea index (AI):is the number of apneas per hour of sleep. • Hypopnea: a decrease in airflow associated with oxygen desaturation • The apnea Hypopnea index (AHI): apneas + Hpopneas per hour of sleep • The respiratory disturbance index (RDI): the total number of obstructive apneas, hypopneas, and central apneas per hour. • The sleep apnea syndrome (SAS):30 or more apneic episodes during a 7-hour period of sleep or an apnea index equals to or greater than 5. • The American sleep association grades sleep apnea as follows: Mild: (AHI 5-15) Moderate: (AHI 5-30) Severe: (AHI >30) .
Sleep Related Breathing Disorders - Definitions • Obstructive sleep apnea:The cessation of airflow in the presence of continued respiratory effort . Due to Upper airway obst. • Central sleep apnea:No flow of air at the nose or mouth associated with a cessation of all respiratory effort. These patients may or may not snore. Heart failure, frontal lobe damage or brain- stem lesions. Oftenno apparent cause, and it is thought to be related to instability of the respiratory control mechanisms. • Mixed apnea:this usually begins as a central apnea with no airflow or respiratory effort followed by increasingly forceful respiratory efforts again with no airflow until airway clears. Obstructive apnea is more common than central apnea though any individual may demonstrate one or more of the above forms of apneas during a night's sleep.
Upper Airway Resistance Syndrome • Episodes of marked partial upper airway obstruction but, no complete obst. of the airway. They are able to maintain their oxygen saturation but need so much respiratory effort to overcome the partial obstruction that they induce frequent micro arousals • They usually have symptoms similar to those with OSA. • Treatment of UARS is similar to that of OSA; the use of CPAP usually is effective. • Main difference between UARS and OSA is the there is no hypoxia related to UARS.
Polysomnogram After complete sleep study the following information is scored: • Lights out • Sleep Latency – from lights out to onset of sleep • Sleep Stages • Non-REM – N1, N2, N3 • REM • Sleep Efficiency – percentage of time asleep • Respiratory Events • Leg Movements • Arousals • Heart Rhythms • Snoring intensity • Lights on • Quality of patient’s sleep compared to baseline
Scoring Respiratory Events Apnea – when all of the following criteria are met • There is a drop in the peak thermal sensor excursion by >90% of baseline • The duration of the event lasts at least 10 seconds • At least 90% of the event’s duration meets the amplitude criteria for apnea • Classified as: obstructive, central, or mixed based on respiratory effort Hypopnea – when all of the following are met 1) The nasal pressure signal excursion drops by 30% of baseline • The duration of this drop occurs for a period of at least 10 seconds • There is a 4% desaturation from pre-event baseline • At least 90% of the event’s duration meets the amplitude criteria The AASM Manual for the Scoring of Sleep and Associated Events, 2007
Hypercapnic CSA • Impaired Central Drive ("Won’t Breathe"):1-Tumors or trauma-induced lesions to brainstem 2-congenital central hypoventilation syndrome (Ondine curse) 3-opioid-induced CSA 4- OHS Impaired Respiratory Motor Control ("Can’t Breathe") 1-myasthenia gravis 2-amyotrophic lateral sclerosis 3-post-polio syndrome 4-myopathies 5-Chest wall syndromes such as kyphoscoliosis
PSG Indications: Nonrespiratory Disorders A PSG preceding an MSLT is indicated for evaluation of suspected narcolepsy or to help differentiate narcolepsy from idiopathic hypersomnia. PSG is indicated for evaluation of suspected periodic limb movement disorder but NOT the restless legs syndrome (RLS; a clinical diagnosis). A PSG is indicated to evaluate (1) nocturnal behavior possibly due to seizures, (2)atypical parasomnia behavior (frequent episodes each night ,stereotypic behavior, or behavior unusual for age), (3) nocturnal behavior/parasomniathat has resulted in injury to the patient or others
Portable Monitoring for OSA in Adults Types of Monitoring Devices Type 1 – in sleep center, attended, overnight polysomnogram Type 2 – record same variables as type 1, unattended (at home) Type 3 – evaluate four physiologic parameters – not sleep respiratory movement and airflow heart rate arterial oxygen saturations (snoring), (position) Type 4 – evaluate one or two parameters (saturation and airflow)
Approach to Reading the PSG Before the PSG is read, a review of the clinical history with special attention to symptoms of sleep apnea, narcolepsy, RLS, and medications is very useful. The presence of underlying lung disease may help explain a low awake arterial oxygen saturation (SaO2) or low baseline sleeping SaO2. A clinical history of pacemaker insertion or known atrial fibrillation is also very helpful in providing a useful interpretation of ECG findings. All digital PSG systems have a view that shows graphical summary information of the entire night. It is often useful to look at the big picture before going through the data in smaller time windows.
Tips for the clinician: • The clinician should recognize that many patients with significant OSA do not complain of daytime sleepiness. • A history of snoring and gasping would suggest a PSG is indicated. • It should also be noted that some patients with OSA complain of insomnia. • A PSG for PAP titration is the standard procedure to select a level of pressure for treatment. • The titration can be performed on a separate night after a diagnostic PSG or during the second part of the night during a split (partial night) study.
POLYSOMNOGRAPHY Indications of Split Study: (1) AHI > 40 /hr with at least 2 hours of monitoring, (2) AHI of 20 to 40 with special clinical circumstances such as severe desaturation or arrhythmia thought due to OSA (3) at least 3 hours remain for the PSG titration. Indications of PSG Repeat: • Time for CPAP titration is < 3 hours • If the patient is being treated on CPAP and is NOT doing well, a repeat PSG study on CPAP is indicated. • PSG is also indicated if a patient on CPAP gains > 10% of body weight to determine whether the pressure is adequate.
DD of OSAS Dyspnea due to pulmonary edema Idiopathic hypersomnia Nocturnal panic attacks Obesity-hypoventilation syndrome (pickwickiansyndrome Simple snoring Asthma Chronic Obstructive Pulmonary Disease Depression GastroesophagealReflux Disease Hypothyroidism Narcolepsy Periodic Limb Movement Disorder
Narcolepsy Classic tetrad of 1- excessive daytime sleepiness (EDS), 2- cataplexy, 3- hypnagogic hallucinations, 4- sleep paralysis. Narcolepsy is thought to result from genetic predisposition, abnormal neurotransmitter functioning and sensitivity, and abnormal immune modulation. Diagnosis The combination of an overnight polysomnogram (PSG) & a multiple sleep latency test (MSLT) showing sleep latency 8 minutes or less and 2 or more sleep-onset random eye movement (REM) periods strong suggests narcolepsy An alternative criterion is a cerebrospinal fluid hypocretin level of 110 pg/mL or less.
Restless Legs Syndrome Periodic leg movements of sleep [PLMS]).PLMS are characterized by involuntary, forceful dorsiflexion of the foot lasting 0.5-5 seconds and occurring every 20-40 seconds throughout sleep. excessive daytime somnolence sleep disturbances, daytime fatigue, and involuntary, repetitive, periodic, jerking limb movements (either while the patient is asleep or while he or she is awake and at rest). A positive family history also aids in the diagnosis of RLS, especially in children.
Polysomnography Measurements • Pulse ox, EEG, EOG, ECG, EMG, oral/nasal airflow, respiratory effort, limb/body movements Definitions • Apnea – lack of ventilation for ≥10 sec with signs of arousal • Hypopnea – decrease in respiratory movement with a drop in O2 sat or with signs of arousal • AHI or RDI =(Apneas + Hypopneas)/hours of sleep Important parameters • RDI • Lowest O2 saturation • Number of desaturations below 90% • Length of time below 90%
Medical Management CPAP • Pressure must be individually titrated • Compliance is as low as 50% • Air leakage, eustachian tube dysfunction, noise, mask discomfort, claustrophobia
PORTABLE MONITORING (HOME SLEEP TESTING, OUT OF CENTER SLEEP TESTING) The tests are not always performed in the home ;hence, the terms HST or PM are not ideal but are used in much of the literature on this subject. In the past, PM has been used to diagnose OSA in settings in which access to PSG is limited or delayed. The original classification used “level I, II, III, and IV” to refer to different classes of monitoring but currently the terminology is “type 1, 2, 3, and 4.” The Centers for Medicare and Medicaid Services (CMS) has a different classification for monitoring The CMS terminology defines the respiratory disturbance index (RDI) as the total number of apneas and hypopneas per hour of monitoring time. Therefore, the index determined by PM (no EEG) would be an RDI using the CMS definition. CMS also refers to PM as HST.
Medical Management • BiPAP • Useful when > 6 cm H2O difference in inspiratory and expiratory pressures • No objective evidence demonstrates improved compliance over CPAP
Portable Monitoring for OSA in Adults Limitations of Type 3 devices • Apnea Hypopnea Index – abnormal breathing events by recording time as sleep can not be recorded • Unless the patient was sleeping the entire recording time, the AHI calculated by a portable monitor will likely be lower than an attended polysomnogram • Can not distinguish sleep stages
Friedman algorithm for treatment • Mild (AHI 5-15) • Symptomless: behavior modification • Symptoms: behavior, device, consider surgery • Moderate (AHI 15-30) • Symptomless: behavior, device • Symptoms: device, consider surgery for device failures • Severe (AHI >30) • Device, consider surgery as adjunct, refer for bariatric surgery BMI>40, consider tracheostomy
Sleep disordered breathing (SDB) is characterized by repetitive episodes of diminished and cessation of breathing during nocturnal sleep (Block et al, 1980). The spectrum of SDB ranges from chronic snoring and upper airway resistance syndrome to obstructive sleep apnea (Guilleminault et al., 1991).
Grades of Sleep Apnea Severity The severity of OSA was determined by the (AHI) Mild: AHI 5-15 Moderate: AHI 15-30 Severe: AHI greater than 30
Obstructive Sleep Apnea Respiratory Disturbance Index (RDI) – no longer used • apneas, hypopneas, respiratory related arousals Apnea-Hypopnea Index (AHI) • total number of respiratory events / hours of sleep Severity of OSA defined by the AHI: < 5 – not sleep apnea 5 – 15 – MILD 15 – 30 – MODERATE > 30 – SEVERE
Diagnosis of the site of upper airway obstruction: • Muller’s Maneuver • Sleep endoscopy • Fluoroscopy • Manometry • Cephalometrics • Dynamic CT scanning and MRI scanning • Mallampati Airway Classification • Friedman Classification
The report can include a measure of the sleep onset time (latency) and the proportion of sleep time spent in each of the sleep stages. Obstructive sleep apnea is characterized by absence of airflow at the nose and mouth despite the presence of respiratory effort (thoracic and abdominal). is caused by a structural narrowing of the upper airway that becomes manifest when muscular tone diminishes during sleep central sleep apnea, the patient’s airway is normal, but airflow is absent because of an absence of respiratory effort. Central apnea is caused by a neurological defect in the control of respiration, such as with bulbar poliomyelitis, degenerative neurological diseases, intracranial neoplasm, brain stem infarction, narcotic or sedative overdose, bilateral cervical cordotomy, Mixed apneais diagnosed when elements of central control and obstruction are both found to be contributing to the apnea. It is generally classified with the predominating element. However, in many cases of advanced obstructive sleep apnea, a central element is notable
Sleep Disordered Breathing • Primary snoring • RDI < 5 • No daytime sleepiness • Upper airway resistance syndrome (UARS) • RDI < 5 • Arousal Index > 5 • Obstructive sleep apnea syndrome (OSAS) • RDI > 5 • O2 desaturation < 90% • Obesity hypoventilation syndrome (Pickwickian) • BMI >30 kg/m2 • Daytime hypercapnia w/ PaCO2≥ 45mmHg • Sleep disordered breathing