New technologies to detect static and dynamic upper airway obstruction during sleep

Area of Science:

• Respiratory Physiology
• Sleep Medicine
• Medical Instrumentation

Background:

• Obstructive breathing disorders during sleep are characterized by increased upper airway resistance.
• Upper airway events are classified as static (apneas) or dynamic (hypopneas, flow limitation, snoring).
• Accurate detection of dynamic obstruction requires sensors with good frequency response, which thermistors lack.

Purpose of the Study:

• To evaluate non-invasive tools for investigating dynamic upper airflow obstruction during sleep.
• To compare the utility of nasal prongs (NP) and forced oscillation technique (FOT) in assessing upper airway events.

Main Methods:

• Utilized nasal prongs (NP) connected to a pressure transducer to assess airflow.
• Employed the forced oscillation technique (FOT) to measure impedance and airway obstruction magnitude.
• Compared the diagnostic capabilities of NP and FOT for static and dynamic upper airway events.

Main Results:

• Nasal prongs (NP) are simple and effective for routine assessment of respiratory events during sleep.
• Forced oscillation technique (FOT) provides a direct index of upper airway obstruction and patency, even during apneas.
• Thermistors are inadequate for detecting dynamic obstruction due to poor frequency response.

Conclusions:

• Nasal prongs (NP) are suitable for routine clinical use due to their simplicity and ease of use.
• Forced oscillation technique (FOT) offers valuable insights in specific applications, including central apneas and REM sleep breathing irregularities.
• Both NP and FOT are useful non-invasive tools for investigating upper airway obstruction during sleep, each with distinct advantages.