1. Physiologic parameters and Polysomnography

2. 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

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

4. 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

5. 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

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

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

9. Ancillary Equipment

10. 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

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

12. 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

13. 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

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

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

18. Light Therapy
Light used to help circadian rhythem

19. HST
Home testing unit for the diagnose of sleep disorder beathing

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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
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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
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22. SLEEP DEFINITION OF TERMS

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

24. 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

25. 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

26. Infant Sleep
Wake
Active sleep
Quiet sleep
Transient

27. 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.

28. 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.

29. 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

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

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

32. 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.

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

34. 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.

35. Sleep Phases and Stages

36. Sleep Phases and Stages
REM
NREM and REM occur in a pattern of 3-5 rhythmic cycles throughout the sleep period
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37. NREM 75% of total nights sleep
Divided into three stages: Stage N1, Stage N2, Stage N3

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

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

40. 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

41. Phases and Stages of Sleep
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42. Sleep Stages or Sleep Cycle
Adults and Peds
Wake
NREM stage1
NREM stage 2
NREM stage 3
REM

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

45. Wave Frequencies and Characteristics
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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
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