Wavelet transform analysis of skin perfusion during thermal stimulation

Area of Science:

• Physiology
• Biomedical Engineering
• Vascular Medicine

Background:

• Skin microcirculation is crucial for thermoregulation and tissue health.
• Vasculopathic patients exhibit impaired microcirculatory function.
• Understanding these responses is vital for managing vascular conditions.

Purpose of the Study:

• To investigate the mechanisms of skin microcirculation response to local heating in vasculopathic patients.
• To analyze the contributions of cardiac, myogenic, and neurogenic activities to microcirculatory response.
• To evaluate the utility of wavelet analysis of Laser Doppler signals.

Main Methods:

• Simultaneous acquisition of Laser Doppler and transcutaneous oxygen pressure (tcpO2) measurements.
• Classification of patients into three groups based on tcpO2 levels (<30, 30-50, >50 mmHg).
• Wavelet analysis of signal oscillations to identify six frequency intervals linked to cardiovascular activities.

Main Results:

• Local heating at 44°C significantly increased relative amplitude and power of cardiac, myogenic, and neurogenic activities across all patient groups.
• The magnitude of increase in amplitude and power was generally higher in patients with more severe vasculopathy (lower tcpO2).
• Spectral analysis revealed distinct contributions of different cardiovascular activities to the microcirculatory response.

Conclusions:

• Wavelet spectral analysis of Laser Doppler signals offers a more comprehensive understanding of skin microcirculation dynamics than traditional perfusion monitoring.
• Thermal stimulation elicits a complex microcirculatory response involving cardiac, myogenic, and neurogenic components, which is modulated by the degree of vasculopathy.
• This advanced signal processing technique can provide valuable insights into vascular function and disease.