Pulmonology Book

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Continuous Positive Airways PressureAka: CPAP

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  1. Indications
    1. Sleep Apnea
    2. Loud continuous snoring
    3. Prevent Intubation in severe respiratory illness
      1. Adult Respiratory Distress Syndrome (ARDS)
      2. Refractory Hypoxemia
  2. Contraindications
    1. Central Sleep Apnea
  3. Physiology
    1. Pressure above atmospheric maintained at airway opening
      1. Maintained throughout respiratory cycle
      2. Acts as airway splint to prevent collapse
      3. Used during spontaneous breathing
    2. Same end-expiratory pressure as with PEEP
    3. Lower Inspiratory pressure excursion than with PEEP
      1. CPAP requires less pressure to open
      2. PEEP requires a greater work of breathing
  4. Dosing
    1. Usual dose: 6 to 12 cm H2O (Range: 3 to 20 cm H2O)
    2. Higher pressure (within range above) indications
      1. Heavier weight
      2. Short-thick necks
      3. More severe Sleep Apnea
  5. Equipment: Sleep Apnea Management
    1. Nasal pillows or full face mask
    2. Small quiet air compressor
  6. Technique
    1. Requires specially-designed, tightly fitting masks
    2. Mask should have pressure-limiting valves
  7. Adverse Effects: Relates to decreased mask tolerance
    1. Nasal dryness or congestion
    2. Mask air leakage
    3. Claustrophobia
    4. Skin irritation or abrasions
    5. Conjunctivitis
  8. Adverse Effects: Methods to improve compliance in Sleep Apnea
    1. Optimize mask fit for size and shape of face
    2. Utilize mask option patient finds most comfortable
      1. Full face mask
        1. Appears similar to Simple Oxygen Mask
      2. Nasal pillows
        1. Soft adapters fit within both nares
      3. Consider alternating methods
    3. Patient should follow-up to make CPAP adjustments
    4. Treat underlying nasal symptoms (e.g. nasal steroid)
    5. Humidify or cool inspired air
    6. Consider otolaryngology consult if CPAP not tolerated
  9. Efficacy: Sleep Apnea
    1. First line, very effective Therapy
    2. Reduces coronary ischemia in those predisposed
      1. Peled (1999) J Am Coll Cardiol 34:1744
    3. Reduces Blood Pressure in hypertensives
      1. Becker (2003) Circulation 107:68
      2. Pepperell (2002) Lancet 359:204
  10. Precautions
    1. CPAP will worsen Central Sleep Apnea
      1. Do not use CPAP empirically without Sleep Study
      2. Decreases respiratory drive
  11. Management: Follow-up of CPAP monitoring in Sleep Apnea
    1. Snoring despite CPAP?
      1. Is CPAP pressure is too low?
      2. Is there a leak at the interface?
      3. Is the patient sleeping with mouth open?
      4. Does the patient use excessive Alcohol?
    2. Weight change since CPAP was started?
      1. Reassess CPAP if weight gain exceeds 10%
      2. Consider overnight oximetry
        1. Calculate desaturation index = (4% desats)/hours
        2. Desaturation index <5 is normal
    3. When was CPAP last checked?
      1. Mask should be changed every 6 months
      2. Check blower every 12 months
    4. Is the patient still symptomatic?
      1. Is patient compliant with CPAP?
      2. Is the patient allowing enough time for sleep?
      3. Are there problems with Sleep Hygiene?
      4. Are other conditions keeping patient awake?
        1. See Insomnia
        2. Consider restless legs
      5. Other conditions making them sleepy (e.g. Narcolepsy)
    5. Problems with CPAP?
      1. Intollerant of air pressure
        1. Activate CPAP ramp up or increase ramp time
        2. Add a CPAP humidifier
        3. Consider a full CPAP face mask
        4. Consider specific devices (Auto-adjust, C-flex)
        5. Consider lowering CPAP pressure by 1-2 cm H2O
        6. Sleep center to calibrate device pressure
      2. Vasomotor Rhinitis or congestion
        1. CPAP heated humidifier
        2. Consider nasal steroid for congestion
        3. Consider intranasal Ipratropium for Rhinitis
      3. Mask or pillow leaks
        1. Adjust the straps, pads
        2. Check that the device is not upside down
        3. Wash face at bedtime and wash device daily
        4. Sleep center to switch mask types
      4. Claustrophobia
        1. Wear mask when reading or watching television
        2. Sleep center to resize mask
      5. Patient pulls off headgear while asleep
        1. Add chin strap or adjust for better fit
        2. Use a disconnect alarm
      6. Difficulty initiating sleep
        1. See Sleep Hygiene
        2. Wear mask when reading or watching television
        3. Assess for other causes (e.g. restless legs)
  12. References
    1. Marino (1991) ICU Book, Lea & Febiger, p. 379-80
    2. Bower (2000) Otolaryngol Clin North Am 33(1):49
    3. Flemons (2002) N Engl J Med 347:498
    4. Gozal (1998) Pediatrics 102:616
    5. Owens (1998) Pediatrics 102:1178
    6. Piccinillo (2000) JAMA 284:1492
    7. Sliverberg (2002) Am Fam Physician 65(2):229
    8. Victor (1999) Am Fam Physician 60(8):2279
    9. Victor (2004) Am Fam Physician :

Continuous Positive Airway Pressure (C0199451)

Definition (MSH)A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. (On-Line Medical Dictionary [Internet]. Newcastle upon Tyne(UK): The University Dept. of Medical Oncology: The CancerWEB Project; c1997-2003 [cited 2003 Apr 17]. Available from: http://cancerweb.ncl.ac.uk/omd/)
ConceptsTherapeutic or Preventive Procedure (T061)
ICD993.90, 93.90
MSHD045422
EnglishCONT POS AIRWAY PRESSURE, Continuous CPAP, Continuous Positive Airway Pressure, Continuous positive airway pressure ventilation treatment, Continuous positive airways pressure, Continuous positive airways pressure therapy, CPAP, CPAP - Continuous positive airways pressure, CPAP - Continuous positive airways pressure therapy, CPAP treatment, CPAP Ventilation, Pressure.continuous positive airway
SpanishCPAP, presion positiva continua de la via aerea, tratamiento de CPAP, tratamiento de ventilacion con presion positiva continua en la via aerea, ventilacion mecanica controlada
Parent ConceptsRespiratory Therapy (C0035239), Positive End-Expiratory Pressure (C0032740), Continuous Positive Airway Pressure (C0199451), Mechanically assisted spontaneous ventilation (C0419003), Positive pressure therapy (C0454517), Duplicate concept (C1274013)
SourcesCSP, ICD9CM, LNC, MSH, MTH, MTHICD9, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)



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