Polysomnogram Interpretation

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Polysomnogram Interpretation

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Medications

• The list of medications is important in the fact
  that certain medication can suppress stage 3 and
  stage 4 sleep, and some medications may suppress
  REM sleep. Each medication may have a different
  affect on the patients sleep stages and
  fragmentation.

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Signs and Symptoms

• The signs and symptoms portion is completed by
  the patient and helps in determining the
  patients overall need for the polysomnogram as
  well as their chief complaint.

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Recording Protocol

• This is the devices and recording instrumentation
  used on the patient during there nocturnal
  polysomnogram.

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Sleep Architecture

• The NREM/REM stage and cycle infrastructure of
  sleep understood from the vantage point of the
  quantitative relationship of these components to
  each other.

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Time in bed

• Time in bed is the total number of minutes that a
  patient spends in bed. This amount varies for
  different age groups and can also vary on an
  individual patient basis. This is important
  because it gives a basic idea as to whether or
  not the patient is spending enough time
  attempting to sleep.

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Total Sleep Time

• Total sleep time is the actual amount of sleep
  time in a sleep period equal to total sleep
  period less movement and awake time. Total sleep
  time is the total of all REMS and NREMS in a
  sleep period. This is important because it gives
  a basic idea as to whether or not the patient is
  achieving enough sleep for the time they are in
  bed.

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Sleep Efficiency

• Sleep efficiency is the proportion of sleep in
  the period potentially filled by sleep, that is,
  the ratio of total sleep time to time in bed.
  This is important because it displays the
  patients overall quality of sleep as it pertains
  to any sleep disorder they exhibit.

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Sleep Latency

• Sleep latency is the period of time measured from
  lights out, or bedtime, to the commencement of
  sleep. This is important because it can show the
  level of sleepiness by how fast the patient gets
  to sleep or their sleep latency. It can also help
  to determine insomnia in patients that displays
  signs of excessive daytime sleepiness but do not
  achieve sleep in a timely manner.

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Wake Percentage

• Wake percentage is the percentage of wake scored
  from lights out to the final wake-up. This is
  important because it will help determine how much
  any sleep disorder is affecting the patients
  sleep architecture.

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Stage 1

• Stage 1 is a stage of NREM sleep that ensues
  directly from the awake state. Its criteria
  consists of a low-voltage EEG with slowing to
  theta frequencies, alpha activity less than
  50,EEG vertex spikes, and slow rolling eye
  movements. Stage 1 percentage is the total time
  spent in stage1 sleep from lights out to the
  final wake-up. Stage 1 generally constitutes
  about 2-5 of sleep.

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Stage 2

• Stage 2 is a stage of NREM sleep characterized by
  the advent of sleep spindles and K complexes
  against a relatively low-voltage, mixed-frequency
  EEG background, high-voltage delta waves may
  compromise up to 20 of stage 2 epochs. Stage 2
  percentage is the total time spent in stage 2
  from lights out to the final wake-up. Stage 2
  generally constitutes 45-55 of sleep.

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Stage 3

• Stage 3 is a stage of NREM sleep defined by at
  least 20 but not more than 50 of the period
  consisting of EEG waves less than 2 Hz and more
  than 75 uV, it constitutes deep NREM sleep. Stage
  3 percentage is the total time spent in stage 3
  from lights out to final wake-up. Stage 3 sleep
  is usually combined with stage 4 sleep and
  usually constitutes 12-18 of sleep.

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Stage 4

• Stage 4 is a NREM sleep that consists of the same
  characteristics a s stage 3 over more than 50 of
  the epoch. Stage 4 percentage is the total time
  spent in stage 4 from lights out to final wake-up.

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REM Sleep

• REM sleep consists of low-voltage, fast frequency
  EEG which may be accompanied by both saw-tooth
  waves and rapid eye movements. REM percentage is
  the total time spent in REM sleep from lights out
  to the final wake-up. REM sleep usually
  constitutes 20-25 of sleep in 4 to 6 episodes.

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REM latency

• REM latency is the period of time from sleep
  onset to the first appearance of REM sleep. This
  is important in showing a short onset of REM
  sleep, which is a sign of Narcolepsy.

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Respiratory Events

• Respiratory events is the breakdown of the
  respiratory changes recorded during the entire
  polysomnogram.

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Obstructive Apneas

• Obstructive apneas are respiratory episodes where
  there is a complete cessation of airflow lasting
  greater than 10 seconds and is accompanied by a
  4 desaturation or an arousal.

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Hypopneas

• Hypopneas are a respiratory episode where there
  is partial obstruction of the airway lasting
  greater than 10 seconds and accompanied by a 4
  desaturation or an arousal.

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Central Apneas

• Central Apneas are respiratory episodes where
  there is no airflow and no effort to breathe
  lasting greater than 10 seconds.

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Mixed Apneas

• Mixed Apneas are respiratory episodes where there
  are features of both obstructive and central
  apneas in the same event.

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Total events

• Total events is the total number of Obstructive
  apneas, Hypopneas, Central apneas, and mixed
  apneas from lights out to the final wake-up.

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RDI

• RDI is an abbreviation for Respiratory
  Disturbance Index. This number is the average
  number of respiratory events per hour of sleep.
  Any RDI lower than 5/hr is considered to be
  within normal limits.

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REM RDI

• REM RDI is the total number of respiratory
  episodes per hour of REM sleep.

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Supine RDI

• Supine RDI is the number of respiratory episodes
  per hour of supine sleep. This is important
  because the patient may have only positional
  apnea and therefore can be treated with
  positional therapy.

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Oxygen (SaO2)

• Baseline the baseline oxygen level for the
  entire polysomnogram.
• Low the lowest oxygen level recorded during the
  polysomnogram.

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Miscellaneous

• The miscellaneous category is for other important
  information regarding the patients
  polysomnogram.

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Blood pressure

• Blood pressures are taken both before and after
  the polysomnogram. The blood pressure before the
  study is to determine a baseline for this
  patient. The blood pressure after the
  polysomnogram is to help determine any
  hypertensive response to sleep apnea or any other
  sleep disorder that may be present during the
  polysomnogram.

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Periodic Limb Movements

• of PLMS the total number of periodic limb
  movements during the polysomnogram.
• PLMS Index the average number of PLMS per hour
  of sleep.

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Arousals

• of arousals the total number of arousals
  recorded during the polysomnogram.
• Arousal index the average number of arousals
  per hour of sleep.

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Technical impression

• The technical impression is the overall breakdown
  and comments for the entire polysomnogram.

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Diagnosis

• The diagnosis portion is where the diagnosis for
  this polysomnogram are listed. The diagnosis of
  Obstructive sleep apnea is based upon the RDI. A
  mild RDI would range from 5/hr. to 15/hr. A
  moderate RDI would range from 15/hr. to 30/hr. A
  severe RDI would be higher than 30/hr. The
  severity can also be determined by other factors
  such as oxygen saturation or position. A person
  with a RDI of 28.2 / hr. with accompanying
  desaturations below 80 may be considered to have
  severe OSA. This is also the portion of the study
  where any Hypoxemia, Periodic Limb Movement
  Syndrome, Restless Legs Syndrome, Insomnia,
  Hypertensive response to apnea, etc.. would be
  noted.

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Recommendations

• This is where any recommendations for treatment
  would be listed. This can include positional
  therapy, nasal CPAP, dental appliance, and
  surgery for treatment of OSAS. This can also
  include medications for treatment of Periodic
  Limb Movement Syndrome, as well as Insomnia or
  any other sleep disorder.