Physiologic parameters and Polysomnography

Polysomnogram (PSG) Record of many different sleep parameters Minimum of three channels of EEG data are required to differentiate sleep from waking and the substages of sleep

Monitoring Vital Signs Electrocardiogram (ECG) Pulse oximeter Snore sensor Respiratory belts Thermal airflow sensor Nasal pressure transducer

Performance of Polysomnography Initiation and completion of overnight and daytime PSGs Required tasks: Ensuring instrumentation is properly functioning Equipment and patient calibrations at the beginning and end of the sleep study Continuous polysomnographic monitoring Correct equipment malfunction Recognize and correct artifacts Document sleep stages and note events continued

Performance of Polysomnography (Cont.) Required tasks: Ensure patient wakefulness and accurately indicate sleep stages during MSLT and MWT Maximize patient comfort and safety Recognize document and respond appropriately to epileptiform activity Respond appropriately to medical emergencies

Special Considerations Physicians may order additional equipment or sensors for patients with: Suspected seizure disorder Possible parasomnias Chronic obstructive pulmonary disease

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Scope of Practice Sleep technologists are allied health professionals who work under the supervision of a licensed physician to assist in the education, evaluation, treatment, and follow-up of patients with sleep disorders Six categories of duties: Instrumentation Performance of polysomnography Professional education Patient care and education Communication Additional tasks Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Instrumentation Must be proficient in the use of all specialized instrumentation Electrode placement Safety, care, and placement of sensors

Ancillary Equipment

Ancillary Equipment Monitoring devices used in PSG to capture data in addition to that needed to detect sleep Most are transducers – devices that convert one form of energy into another Pressure transducers and thermocouples for airflow Respiratory-induced plethysmography and strain gauges to measure respiratory effort

Snore microphones and sensors for the presence of snoring An oximeter for monitoring oxygenation End tidal carbon dioxide monitor to measure ventilation

Airflow Measures Thermal sensors and pressure transducers Current technology used in PSG Airflow is the patient’s inspiratory and expiratory pattern Qualitative representation of air movement Not measured as a volume

Thermal Sensors Thermal Sensors generate a voltage as temperature changes Cool air passes over sensor during inhalation Warm air passes over sensor during exhalation Thermistor requires power source Thermocouple makes use of thermoelectric effect A voltage develops at the junction of two dissimilar metals proportional to temperature change

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Pressure Sensors Pressure transducer detects pressure or vacuum at nares produced by airflow Several technologies exist Piezo-resistive effect is sometimes used Power source is required Constant current through a metal film As film stretches the metal becomes resistive to current Change in resistance results in inverse change in current Greater resistance results in decreased current Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Pulse Oximetry The indirect monitoring of oxygenation Sensors detect light wave absorption Infrared light absorbed better by oxygenated blood Red light absorbed better by deoxygenated blood Approximation of blood oxygen level The two variations of light are detected on photoreceptors The conversion of energy results in warming of the skin Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Pap Machines Continuous positive airway pressure (CPAP) Bilevel positive airway pressure (Bipap or Vpap) Auto adjusting Pap

Actigraph Is used as a sleep diary Patient exposure to light Patients movement

Light Therapy Light used to help circadian rhythem

HST Home testing unit for the diagnose of sleep disorder beathing

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Snore Microphones Standard diaphragm microphones Condenser and dynamic Respond to any pressure wave capable of moving diaphragm Sense background noise Piezoelectric sensors Touch the skin for stronger patient signal Less background noise Mechanical energy is converted to voltage Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Position Sensors Various methods exist for monitoring position Often visually assessed by technologist Prone to error for various reasons A liquid mercury switch can be used to explain the concept of a position sensor Older technology using toxic metal Digital sensors are safer and more precise An accelerometer measures a change in speed or direction Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

SLEEP DEFINITION OF TERMS

Polysomnogram Is a recording of various physiologic parameters relating to sleep, which is also known as a sleep study

Sleep Times Sleep onset- Time in minutes after lights out (when the patient starts trying to fall asleep) when the first epoch of any stage of sleep is observed Total Recording Time (TRT): Time in bed is from lights out until end of the recording. Total Sleep Time (TST): Time in minutes from sleep onset until the final awakening less wake after sleep

Sleep Efficiency (SE): Ratio of the total sleep time/total recording time (TST/TRT), a measure of the percentage of the TRT spent sleeping Sleep Maintenance (SM): Ratio of the total sleep time/sleep period time (TST/SPT), a measure of the percentage of the SPT spent sleeping REM Sleep Latency: Elapsed time in minutes from sleep onset to but not including the first scoreable epoch of REM sleep

Infant Sleep Wake Active sleep Quiet sleep Transient

Breathing Events During Sleep Apnea: A drop in the peak thermal sensor excursion by 90% or greater of baseline, a duration of at least 10 seconds, and at least 90% of the event’s duration meets the amplitude reduction criteria. Classifications: 1. Obstructive apnea: Meets apnea criteria and is associated with a continued or increased inspiratory effort throughout the entire period of absent airflow. 2. Central apnea: Meets apnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow and . 3. Mixed apnea: Meets apnea criteria and is associated with absent inspiratory effort in the initial portion of the event, followed by resumption of inspiratory effort in the second portion of the event AASM Manual for Scoring Sleep, 2007, p.45.

AASM Hypopnea: A 30 % or greater fall (but less than 90%) in the nasal pressure signal excursion for at least 90% of the event duration from pre-event baseline, the duration of which lasts at least 10 seconds, and is associated with a 3% or greater desaturation or EEG arousal. 1. Obstructive hypopnea: Meets hypopnea criteria and is associated with a continued or increased inspiratory effort throughout the entire period of absent airflow. 2. Central Hypopnea: Meets Hypopnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow CMS Obstructive Hypopnea: A 30 % or greater fall (but less than 90%) in the nasal pressure signal excursion for at least 90% of the event duration from pre-event baseline, the duration of which lasts at least 10 seconds, and is associated with a 4% or greater desaturation. CMS Central Hypopnea: Meets Hypopnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow and a 4% desaturation.

Respiratory Effort Related Arousals (RERA): A sequence of breaths lasting at least 10 seconds characterized by increasing respiratory effort or flattening of the nasal pressure waveform leading to an arousal from sleep when the sequence of breaths does not meet the criteria for hypopnea or apnea. With respect to scoring a RERA the preferred methods for assessing change in respiratory effort ares nasal pressure and inductance plethysmography

Apnea Hypopnea Index (AHI): AASM AHI: The mean number of apneas, hypopneas per hour of sleep

Respiratory Disturbance Index (RDI): The mean number of apneas, hypopneas and RERA’s per hour of sleep

Arousal We score an arousal during sleep if there is an abrupt shift of the EEG frequency including alpha, theta and /or frequency greater than 16 hz (but not spindles) that lasts at least 3 seconds, with at least 10 sec of stable sleep preceding the change. Scoring of arousals during REM sleep requires a concurrent increase in chin EMG lasting at least 1 second.

Awakening When more than 50% of a 30-second epoch is scorable as wakefulness and was preceded by at least 10 seconds of sleep.

Periodic Limb Movement: We score leg movements as periodic if they occur in a series of 4 or more repetitive leg movements each lasting 0.5 to 10 sec. with 5 to 90 sec. from onset to onset of consecutive movements. To score a particular limb movement it must a minimum EMG voltage of 8 uv above the resting baseline before the event. onset of the leg movement is the point when the leg EMG voltage increases 8 or more uv above the resting baseline EMG voltage. The end of the leg movement is when amplitude fails to less than 2 uv above the resting baseline EMG voltage. Do not score a LM if it occurs 0.5 sec. before or after an apnea or hypopnea.

Sleep Phases and Stages

Sleep Phases and Stages REM NREM and REM occur in a pattern of 3-5 rhythmic cycles throughout the sleep period Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

NREM 75% of total nights sleep Divided into three stages: Stage N1, Stage N2, Stage N3

REM 20%-25% of total night’s sleep Also known as Stage R Occurs every 90-110 minutes Length increases throughout the night with the longest stretch in the last 1/3 of the night

NREM and REM occur in a pattern of 3-5 rhythmic cycles throughout the sleep period

Sleep Phases and Stages Histogram A graphical display of the sleep stages and sleep-related events along a time axis Hypnogram A graphical display of the sleep stages, only along a time axis depicting a sleep session

Phases and Stages of Sleep Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Sleep Stages or Sleep Cycle Adults and Peds Wake NREM stage1 NREM stage 2 NREM stage 3 REM

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. Stages N1-N2 Sleep Most adults enter sleep through stage N1 N1 continues until a K complex K complexes or Sleep Spindles indicate a sleeper has entered stage N2 sleep Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Stage N3 Sleep Slow-wave activity occupies at least 20% of an epoch Waves have frequency of 0.5-2 Hz and peak-to-peak amplitude of 75 V as measured over the frontal regions Vital signs and muscle tone are stable

Wave Frequencies and Characteristics Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.

Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. REM Sleep Characterized by a tonic pattern of low-voltage, mixed-frequency brain wave activity similar to wakefulness Appearance of rapid eye movements and a significant reduction in skeletal muscle tone Sawtooth waves Skeletal muscles are paralyzed except for the diaphragm Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc.