Autonomic nervous system function in patients with primary obstructive sleep apnoea syndrome

Area of Science:

• Cardiology
• Neurology
• Sleep Medicine

Background:

• Obstructive sleep apnoea syndrome (OSAS) is a common disorder.
• Autonomic nervous system (ANS) dysfunction may play a role in OSAS.
• The impact of surgical outcomes on ANS function in OSAS is not fully understood.

Purpose of the Study:

• To investigate autonomic nervous system function in patients with OSAS.
• To compare ANS function between patients who were surgically cured and those considered surgical failures.
• To determine if ANS dysfunction contributes to surgical failure in OSAS.

Main Methods:

• Cardiovascular reflex tests including Valsalva manoeuvre, respiratory sinus arrhythmia, isometric handgrip, and head-up tilt were employed.
• Ten patients cured by uvulopalatopharyngoplasty were compared to nine surgical failures.
• Patients' autonomic nervous system function was assessed using these tests.

Main Results:

• No definite autonomic nervous dysfunction was diagnosed in any patient.
• Two patients showed signs of moderate vagal dysfunction.
• Overall sympathetic overactivity was noted, correlated with oxygen desaturation indices, and persisted post-treatment. No significant differences were found between the cured and failed surgical groups in any test.
• Four patients lacked bradycardia during sleep apnoea, with two exhibiting decreased respiratory sinus arrhythmia when awake.

Conclusions:

• Autonomic nervous dysfunction does not appear to contribute to surgical failure in OSAS.
• The incidence of autonomic nervous dysfunction is not increased in primary OSAS patients.
• Vagal responsiveness may differ between awake and sleeping states, or other factors influence bradycardia during apnoea.