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Introduction ⬇

Following the diagnosis of OSA, a continuous positive airway pressure (CPAP) titration study is performed to calibrate CPAP therapy. The CPAP machine supplies air under pressure, acting as a pneumatic splint that keeps the upper airway open during sleep. The pressure required depends on the severity of the OSA and can vary; therefore, the patient is typically required to return to the sleep laboratory on a second night to repeat the sleep study (PSG) while wearing an CPAP mask. Positive airway pressures are titrated until the apneas "break." Under some circumstances (e.g., severe sleep apnea), titration can be done on the same night as the PSG. In that case, it is termed a split-night study. The CPAP machine provides continuous positive pressure during both inspiration and expiration. Conversely, bilevel positive airway pressure (BiPAP) uses two separate pressures: one during inspiration and a lower pressure during expiration. In cases in which CPAP is not well tolerated, BiPAP may be a better alternative. A CPAP unit may be used in the home and is preset to the test pressures that ameliorated the apneas.

Procedure ⬆ ⬇

  1. On the day of the titration, instruct the patient to avoid caffeinated beverages, alcohol, and sedatives and to keep a sleep log.

  2. Allow sufficient time before testing to attach the patient to the monitoring devices and other equipment, including the CPAP machine. A brief orientation to CPAP should take place before the actual day of titration to relieve the patient's anxiety.

  3. The sleep technologist takes a brief patient history. The sleep log is reviewed, and a bedtime questionnaire is completed. The patient then prepares for sleep.

  4. Have the technologist apply the electrodes, monitors, sensors, microphone, and interface with the polygraph.

  5. Fit the patient with a CPAP mask and ensure that it can be easily removed in case of discomfort, shortness of breath, or claustrophobia.

  6. Provide a bedside commode because the leads are relatively short.

  7. Adjust CPAP pressures throughout the sleep period, beginning with 3-5 cm H2O and increasing in 2.5-cm H2O increments until the apneas "break." Time increments can vary from 15 minutes-2 hours per pressure setting. Decisions are based on protocols being used, severity of sleep apnea, and patient tolerance for testing. If BiPAP is being performed, inspiratory and expiratory pressures are adjusted separately, keeping the inspiratory pressure at least 2-4 cm H2O above the expiratory pressure.

  8. After the test, remove the equipment and have the patient complete another questionnaire, which the sleep technologist evaluates and scores.

  9. Follow guidelines in Chapter 1 for safe, effective, informed intratest care.

Clinical Implications ⬆ ⬇

  1. An AHI >5 indicates OSA, which is characterized by the absence of airflow for >10 seconds in the presence of continued respiratory effort. CPAP used in treating OSA has been shown to be clinically beneficial.

  2. Following even short-term CPAP use, there is documented evidence of rapid symptomatic improvement, with restoration of nocturnal sleep and subsequent lessening of daytime sleepiness and improved quality of life.

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain test purpose and CPAP titration procedure.

  2. Reassure patients that the mask can easily be removed if anxiety or claustrophobia develops.

  3. Record the patient's age, height, weight, and gender. A brief history is taken, and before- and after-bedtime questionnaires are filled out.

  4. Have the patient prepare for sleep at the normal time in the usual manner.

  5. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Explain test outcome and possible need for follow-up testing and treatment. Depending on the test outcome, a CPAP unit may be ordered for home use. Modify the nursing care plan as needed.

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Interfering Factors ⬆ ⬇

  1. Caffeinated beverages and alcohol can delay sleep onset or exacerbate OSA, which may interfere with determining optimal pressure settings.

  2. Changes in the patient's daily routine on the day of titration can alter results.

  3. Patients with a deviated nasal septum or chronic sinusitis may have problems tolerating the CPAP. The use of CPAP is contraindicated in persons with severe bullous emphysema or chronic perforated tympanic membrane.

  4. Skin irritations from tight-fitting masks (especially on the bridge of the nose), nasal congestion, and headaches are occasional complaints with the use of CPAP.

  5. The benefit of CPAP to patients with CSA has not been well documented.

Reference Values ⬆

Normal