Alternative Noninvasive Measures of Respiratory Effort

The use of esophageal pressure sensors has disadvantages preventing its widespread use in polysomnographic diagnostic sleep studies. This is in part due to the

Priueniotachograph (Ua)

Priueniotachograph (Ua)

patient's fear of discomfort and the technician's hesitancy to apply the sensor. From our own experience in Dortmund, it is not uncommon that patients remove the esophageal balloon some time after successful application.

Several noninvasive measures have shown to correlate well with respiratory effort. Pulse transit time (PTT) has shown to detect inspiratory effort (38). This method is based on the time differential of the pulse wave between two points (39) within the arterial tree. PTT has also shown to detect arousals during sleep (40). More recently, noninvasive measurement of diaphragmatic electromyogram (EMGdi) with surface electrodes (41) has shown to correlate with esophageal pressure in OSA (42) and partial upper airway obstruction as well (43). When snoring is present in patients with partial upper airway obstruction, sound pressure levels allow estimation of relative changes in esophageal pressure (44). Of course, this method will not work for complete upper airway obstruction where complete flow limitation will put an end to snoring. The forced oscillation technique (45) is based on the application of a high-frequency oscillation applied with a nasal mask to the upper airway (5-20 Hz). It continuously measures the relationship between pressure and flow. This technique has also shown to be useful in determining effective CPAP pressure (46). For further reference on the methods described above, a detailed review was published by Farre et al. (47) in 2004.

A summary of the diagnostic criteria for UARS versus OSA is given in Table 1.

Sleeping Solace

Sleeping Solace

How To Better Your Sleep For A Better Life. Understanding the importance of good sleeping habits is very beneficial to the overall health of an individual in both mental and physical levels. Learn all the tricks here.

Get My Free Ebook


Post a comment