Sleep Disordered Breathing (OSA) CTS 2011 Guideline

Symptoms:

1. Recurrent nocturnal awakening
2. Unrefreshing sleep
3. Daytime sleepiness
4. Bed partner c/o
   • loud snoring,
   • nocturnal apnea
   • choking episodes

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4 types of Sleep apnea

1. Obstructive Sleep Apnea (OSA)
   • More common in overweight pt
   • More likely to have car crashes due to xs sleepiness & falling asleep while driving.
   • Increased risk to develop cardiovascular and cerebrovascular dz
2. Central Sleep Apnea
   • Cheyne-Stokes variety
   • Common in pt with heart failure and cerebrovascular dz
3. Complex sleep apnea
4. Sleep hypoventilation

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Management

1. Must distinguish between the different types of sleep apnea – different Tx
2. Provincial legislation for reporting drivers with untreated sleep apnea
3. Pt education http://www.lung.ca/sleepapnea
   • inform pt that EtOH and sedatives worsen OSA & sleep hypoventilation

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Dx

• All pt w/ suspected OSA should complete an assessment of daytime sleepiness
  • eg. Epworth Sleepiness Scale
• All pt should be assessed within 6 months of the referral by the dx sleep facility
• Pt with the following should be investigated within 4 weeks of the referral:
  1. suspected severe OSAS
  2. Working in safety-critical occupations
     • Working with machinery or employed in hazardous occupations
     • Commercial drivers, railway engiineers
     • airline pilots, air traffic controllers, aircraft mechanics
     • Ship captains & pilots
  3. High risk of a car crash
     • drivers who admit to having fallen asleep while driving within the last 2 yr
  4. Co-morbid condition
     • Unstable ischemic heart dz
     • recent cerebrovascular dz
     • CHF
     • refractory systemic HTN
     • Obstructive/restrictive lung dz
     • pulmonary hypertension
     • hypercapnic respiratory failure
     • pregnancy

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Dx modalities:

Level 1: portable monitoring studies is the test of choice when readily available

• complete laboratory technologist-attended PSG (polysomnnography)

For OSA dx in pt with a moderate to high pretest probability:

• Level 2: full ambulatory PSG
• Level 3: multi-channel cardio-respiratory recording devices
• Level -4 oximetry

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Tx

All pt with daytime symptoms and OSA should be be Tx

1. Wt loss in all overweight pt with OSA, but attempts to lose wt shouldn’t delay additional Tx
2. All pt in a safety critical occupation or at high risk of a car crash should be told to cease their occupation or personal driving until their medical assessment has been complete and Tx established
3. Review Tx if persistent low CPAP use (<4hr / night)
4. Tx adherence assessed within 2-4 weeks of initiations and f/u within 3 mo to assess symptomatic response
5. Oral appliances
   • first line for pt with mild or moderate OSA with min daytime symptoms
   • Should be fitted by trained dental practitioners
   • pt should undergo f/u sleep monitoring with the oral appliance to ensure effective Tx
6. Upper airway Sx
   • OSA pt with large tonsils – ref to ENT for tonsillectomy evaluation
   • OSA should be excluded before upper airway surgery for snoring
   • Palatal Sx for snoring – potential difficulty of using CPAP later if they have OSA
   • Laser-assisted uvulopalatoplasty – not recommended for Tx of
7. OSA during Anaesthesia & post-op period may increase OSA
   • OSA pt should be tx prior to Sx and continued on during the post-op period

Asymptomatic Adult OSA

• Tx if pt has
  • co-morbid conditions: sig cardiovascular dz (including HTN) etc
  • work in a safety critical occupation
  • AHI (Apnea/hypopnea Index) >19/h
• 1o Tx: CPAP at a fixed Pressure
• Alt: APAP only in the absence of comorbid dz
• Bariatric (wt loss) Sx should be considered in Rx of OSAS in morbidly obese pt (BMI >=40) and BMI>=35 + serious comorbid dz
  • after failure to lose wt or to maintain wt loss with dietary and lifestyle approaches
  • A dx sleep study in asymptomatic pt after achievement of max wt loss (usually 1yr post-bariatric sx) to re-evaluate OSAS severity, before abandoning CPAP or other OSAS Tx

CSAS (Central sleep apnea syndrome) in HF pt

• Optimization of medical HF Tx should be the first step
• If CSAS persist after optimal medical HF Tx, consider 3 months trial of CPA
  1. AHI <15 – repeat sleep study, CPAP can be continued
  2. AHI >=15, d/c CPAP

CompSA

• A form of central apnea with persistence or emeregence of central apneas or hypopneas (with a CAI >5) on exposure to CPAP or spontaneous-mode BPAP when obstructive events have disappeared (CPAP titrated to eliminate OSAS)
• recognized as a distinct clinical entity

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Optimal PAP technologies

1. Variable expiratory pressure – no clear advantages over fixed CPAP
   • consider in CPAP-intolerant pt
2. BiPAP – reserved for pt with ventilatory failure
3. ASV (automatic servoventilation) – for pt with CSR syndrome or CompSA
   • unknown long-term benefits over CPAP or BPAP