Analysis of Oxygen Desaturation Index (ODI) vs Apnoea Hypopnoea

Document Sample
Analysis of Oxygen Desaturation Index (ODI) vs Apnoea Hypopnoea Powered By Docstoc
					Analysis of Oxygen Desaturation
Index (ODI) vs Apnoea Hypopnoea
Index (AHI) of Limited Sleep Study

           Emma O’Rourke
         Respiratory Scientist
  Midland Regional Hospital, Mullingar
Sleep Apnoea
   Definition: (As per ISS Guidelines)
    ‘Obstructive Sleep Apnoea Syndrome (OSAS) is a
    complex disorder characterised by brief
    interruptions of breathing during sleep. Airflow
    into and out of the lungs is reduced or
    diminished due to closure of the upper airway,
    despite continued respiratory effort.’
Screening Programme
   Oct 2007 – Sleep Apnoea Screening
    Programme introduced to Sleep Lab to
    ensure that those with Severe Sleep
    Apnoea Syndrome (SAS) were
    prioritised and did not have to wait
    more than 4 months for a limited sleep
    study to be preformed.
Screening Programme
Involves
   Overnight Pulse Oximetry
   Obtaining an Epworth Sleepiness Scale
    Score
   Life-style & Sleep pattern Questionnaire
   Noting BMI, Age, Gender, Occupation.
Screening Programme
   ALL patients go onto to have a home
    limited sleep study
   But those with an ODI of ≥30 are
    prioritised to have a sleep study within
    4 months of referral.
   Those with an ODI of <30 go onto
    routine waiting list for sleep study
    (approx 9-12 months).
Study
   In this study – 50 patients were
    randomly identified & results analysed.

Aim
 To see if the ODI from the screening
  process has accurately predicted
  severity of SAS? and
 Is screening patients worthwhile?
   Definitions
ODI
 Desaturation of ≥ 4% for a min of 10 secs

  per hour of sleep

AHI
 Apnoea hypopnea index per hour of sleep
Gender

   Male   46 patients

   Female 4 patients
Epworth Sleepiness Score

   Score   0-5   5

   Score   6-9   18

   Score   10+   27
BMI

   Normal        5 patients
   Overweight   17 patients
   Obese        28 patients
Age

   20-39 yrs    4 patients
   40-59 yrs   26 patients
   60-79 yrs   19 patients
   80+ yrs      1 patient
ODI Results

   Normal (<5)          7 patients
   Mild (5 – 15)        15 patients
   Moderate (16 – 29)   11 patients
   Severe (30+)         17 patients
Analysis
7 Normal ODI (< 5/hr)
AHI showed
 Normal (<5)      2 patients (29%)
 Mild (5 – 15)        4 patients
 Moderate (16 – 29)   0 patients
 Severe (30+)         1 patient
Graph
        1




            2




                Normal
                Mild
                Severe




        4
Analysis
15 Mild ODI ( 5 – 15 /hr)
AHI showed
 Normal (<5)          0 patients
 Mild (5 – 15)     11 patients (73%)
 Moderate (16 – 29)  4 patients
 Severe (30+)         0 patient
Graph

   4




             Mild
             Moderate




        11
  Analysis
11 Moderate ODI ( 16 – 29 /hr)
AHI showed
 Normal (<5)        1 patients
 Mild (5 – 15)      2 patients
 Moderate (16–29) 6 patients (55%)

 Severe (30+)      2 patients
Graph
            1

    2




                2




                    Normal
                    Mild
                    Moderate
                    Severe




        6
  Analysis
17 Severe ODI ( 30+ /hr)
AHI showed
 Normal (<5)          0 patients
 Mild (5 – 15)        0 patients
 Moderate (16–29)     0 patients
 Severe (30+)     17 patients(100%)
Graph
        Severe




        100%
Conclusion 1

    The Screening Programme is an
    efficient way of accurately predicting
    those with Severe SAS (100%)
Conclusion 2
Beneficial for patients with increased risk
  factors:
 RTA due to sleepiness

 Commercial drivers

 Type 11 diabetes

 Unexplained cardiovascular disease

 Heart Failure
Conclusion 3
   Finally, in an environment of prolonged
    waiting lists (especially over 1 year) and
    limited resources – consideration of this
    method to screen all referrals, with
    appropriate prioritization given for sleep
    study, is advisable.
Positive Outcomes
   Contact with the patient at an early
    stage – sleep referral process explained
   Reduced DNAs
   Allows severe patients quicker access to
    consultants (major choke point)
Thank You!

       Any questions?