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Updated: Jul 17, 2026
07:09
Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise
Published on: February 20, 2017
Respiratory control during volume-cycled ventilation in normal humans
Summary
Neuromechanical inhibition is weak, offering minimal feedback to control breathing during high-volume mechanical ventilation. This study found no apnea or significant rate changes with increased tidal volumes (VT).
Area of Science:
- Physiology
- Respiratory Medicine
- Mechanical Ventilation
Background:
- Mechanical ventilation can influence respiratory drive.
- Understanding neuromechanical inhibition is crucial for optimizing ventilator settings.
- High tidal volumes may suppress spontaneous breathing efforts.
Purpose of the Study:
- To assess the inhibitory effect of high ventilation volumes on respiratory rhythm.
- To quantify neuromechanical inhibition during volume-cycled mechanical ventilation.
- To determine the negative feedback capacity of this inhibition on respiratory control.
Main Methods:
- Two protocols were used in healthy awake subjects.
- Protocol 1: Increasing tidal volume (VT) in assist/control mode and observing for apnea or rate reduction.
- Protocol 2: Discontinuing controlled mechanical ventilation (CMV) during apnea and measuring time to next spontaneous effort.
Main Results:
- Increasing VT in assist mode did not cause apnea and only modestly reduced respiratory rate (f).
- End-tidal PCO2 (PETCO2) significantly decreased with higher VT.
- No apnea was observed after CMV discontinuation; breath timing remained consistent.
Conclusions:
- Neuromechanical inhibition is weak and provides minimal negative feedback.
- It offers little help in controlling PCO2 during high VT demands.
- Current mechanical ventilation strategies may not be significantly limited by this inhibitory mechanism.
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