A Respiratory Marker Derived From Left Vagus Nerve Signals Recorded With Implantable Cuff Electrodes

Area of Science:

• Biomedical Engineering
• Neuroscience
• Cardiovascular Research

Background:

• Resistant hypertension (RH) management can benefit from closed-loop left vagus nerve stimulation (CL-LVNS).
• CL-LVNS systems require a variable to avoid stimulation during normal hypertension, such as during exercise.
• The left vagus nerve (LVN) transmits respiratory signals, suggesting its potential for monitoring respiration.

Purpose of the Study:

• To investigate the feasibility of recording respiratory signals from the LVN using implantable methods.
• To determine if a reliable respiratory marker can be derived from these LVN recordings.

Main Methods:

• Experiments were conducted on 14 anesthetized pigs with controlled changes in respiratory frequency and volume.
• Left vagus nerve electroneurograms (VENG) were recorded using cuff electrodes.
• VENG data were processed to derive respiration-related neural profiles (RnPs) and correlated with respiratory cycles (RCs).

Main Results:

• Respiration-related neural profiles (RnPs) showed morphological similarity to respiratory cycles (RCs).
• RnPs accurately mirrored RCs in timing and magnitude, with linear amplitude increase corresponding to lung inflation (R² 0.85–0.99).
• Respiratory frequency changes similarly affected both RnPs and RCs.

Conclusions:

• Respiration-related neural profiles (RnPs) contain accurate timing and magnitude information of respiratory parameters.
• LVN-derived RnPs can be obtained using implantable techniques.
• RnPs show potential as respiratory markers for implantable closed-loop systems.