How To Order and Interpret Sleep Lab Tests by tlv10296


									How T O d and I
H                        Sleep
    To Order d Interpret Sl
          Lab Tests

           Adam J. Sorscher, MD
Department of Community and Family Medicine
    Dartmouth-Hitchcock Medical Center

               April 16, 2009
        Learning Objectives
• Understand the protocol of the MSLT and
  its usefulness/limitations in evaluating
• Describe how the "AHI" is determined and
  discuss why it is an imperfect means of
  grading sleep apnea.
  Explain how actigraphy t ti can b
• E l i h          ti    h testing      be
  used to characterize insomnias.
  Sleep Disorders and Sleep Deprivation:
       An Unmet Public Health Problem

50-70 million Americans suffer from chronic disorders of
sleep and wakefulness

The annual direct cost of sleep-related problems is over
$ 200 billion
             Case: Ms O
• 30 yo. Woman with EDS since high school
• In bed at 11 pm, SL: 10 minutes, MONA 5-
          brief            7:30-8
  10 but brief, wake up at 7:30 8 am*
• 7-8 c. coffee per day to stay awake
• Occasionally soft snoring; no leg pain noc
• Weak knees when she laughs hard
• PE: wnl. BMI = 26
            Sleepy? So what?
• Cognitive Function: attention span,
  concentration, memory, language fluency,
  problem solving, response time, judgment
• Mood: irritability / poor emotional control and
  low frustration tolerance affects relationships at
  home, school, and work
  Danger!: “Micro-sleeps” b hi d the wheel
• D       ! “Mi        l    ” behind h     h l
   – Public Health matter, as well as personal issue
       p                      y
   Sleepiness and Public Safety

• 270 000 motor vehicle accidents (20% of
  total) annually are sleep-related ~ 1,500

• Disasters such as Chernobyl, Three Mile
  Island, Challenger, Bh
  I l d Ch ll              l    d Exxon
                      Bhopal, and E
  Valdez were officially attributed to errors in
  judgement induced by sleepiness or fatigue.
Rob Raneri
June 26 2002
US Army Major driving to
his last day of work before
he was to be married.

Killed when a 19 year old
who had been up all night
playing video games fell
asleep at the wheel and
crashed in to him

Major Raneri’s fiance, Amy
Huther learned one week
later that she was carrying
his baby

Fine: Misdemeanor $200
   Assessment of Sleepiness

• Behavioral: yawning, ptosis
• Subjective: Epworth Sleepiness Scale
• Objective:
            y         p
Excessive Daytime Sleepiness

  The I  ffi i t Sl     S d
• Th Insufficient Sleep Syndrome
  Obstructive l
• Ob t ti sleep apnea
•N    l
  Idiopathic h
• Idi                i
        thi hypersomnia
Total Sleep Requirement:
Sleep Logs
    g p y              p
Actigraphy: A Good Sleeper
All individuals with bothersome
            y         p
excessive daytime sleepiness
(EDS) should be referred to a
(   )
sleep center
Obstructive Sleep Apnea
•   EEG x4
•   Eyes x2
•   Chin x1
•   Legs x2
•   EKG x 1
•   Airflow x 2
•   Oximetry x 1
•   Strain gauges
What is an apnea? A hypopnea?
 Does Everyone Have Sleep
          A    ?
   Does Everyone Need

(Does Ms. O. have Sleep Apnea?)
             p p           g
         Sleep Apnea Scoring
Normal               <4

Borderline           5-14
                     5 14

Mild                 5 30

Moderate            31-50

Severe               >50
           Sleep Apnea:
      Night-by-Night Variability
      Ni h b Ni h V i bili
Bodily Position

Sleep Architecture


    The MSLT: an objective
             t f l     i
   measurement of sleepiness

Five 20-minute nap opportunities are given at two-
 hour intervals

 Parameters measured are:
     - average latency to sleep onset
     - appearance of REM sleep
    Interpreting MSLT Results
Mean Sleep
Latency:              Interpretation
>10 min.             ( y             g )
              Normal (maybe it’s fatigue)

5-10 min.           Moderately Sleepy
                         (OSA? IH?)

<5 min.              Severely Sleepy
                 (and SOREMs 2/5 = narcolepsy)
    p       yp
Idiopathic Hypersomnolence

 Daytime Sl
 D ti          i
         Sleepiness d      it d     t
                      despite adequate
       quantity of sleep at night

    No sleep-disordered breathing

 MSLT 5-10 min. and 0-1 SOREMS (ie
   does not quite meet narcolepsy
            q                 p y
            Ms. O’s
            Ms O s MSLT Report
    Nap #      Time      Sleep Latency   REM latency
      1        8 06 am
               8:06         3.5 i
                            3 5 min.       5.5 i
                                           5 5 min
      2      10:02 am       6.0 min.         ----
      3      11:58 am       1.5 min.      11.5 min.
      4       2:01 pm       7.0 min.         ----
      5       4:04 pm       8.5 min.         ----

•   Preceeding Night’s TST: 440 min.
•   AHI = 7.8
•   Mean Sleep Latency: 5.3 min.
•   SOREMs: 2/5
            y         p
Excessive Daytime Sleepiness

  Sleep d i ti
• Sl    deprivation
  Obstructive l
• Ob t ti sleep apnea
•N    l
  Idiopathic h
• Idi                i
        thi hypersomnia
    Sleep Lab Tests: Concluding
             R      k
• Mild Sleep Apnea: offer a trial of CPAP,
  but don’t push it (consider weight loss or
  positional therapy)
  p               py)

• MSLT: may fail to identify pathological

• Actigraphy: a useful test; no
   EDS: Concluding Remarks
• EDS places a great burden on public
  health and individual well-being

• Disorders of genuine hypersomnolence
  are readily diagnosable and treatable

• A thorough evaluation of EDS might
  require more than just testing for sleep-
  disordered breathing

To top