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Pulmonary denervation in humans. Effects on dyspnea and ventilatory pattern during exercise
R J Kimoff1, T H Cheong, M G Cosio
1Department of Medicine, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada.
The American Review of Respiratory Disease
|November 1, 1990
Summary
Pulmonary autonomic nerves influence ventilation levels but not breathing patterns during exercise. These nerves do not significantly contribute to the sensation of breathlessness in humans.
Area of Science:
- Cardiopulmonary physiology
- Neuroscience
- Respiratory medicine
Background:
- The role of pulmonary autonomic nerves in respiratory sensation, particularly dyspnea, remains incompletely understood.
- Pulmonary neurogenic mechanisms may influence ventilation patterns and contribute to breathlessness.
Purpose of the Study:
- To investigate the role of pulmonary autonomic nerves in ventilatory control and respiratory sensation.
- To examine the impact of pulmonary denervation on exercise responses using heart-lung transplant recipients.
Main Methods:
- Studied ventilatory response, respiratory drive (P0.1), and breathlessness (modified Borg scale) during maximal incremental exercise.
- Compared four female heart-lung transplant recipients with ten age-matched control subjects.
Main Results:
- Transplant recipients showed a higher ventilatory response to CO2 output, achieving similar peak ventilation despite lower peak CO2 output.
- Ventilatory timing, tidal volume to inspiratory capacity ratio, and respiratory rate patterns were similar between groups at peak exercise.
- Dyspnea ratings at similar ventilation levels and as a function of respiratory drive were comparable between transplant recipients and controls.
Conclusions:
- Pulmonary neurogenic mechanisms are involved in regulating the overall level of ventilation during exercise, but not its pattern.
- These neural pathways do not appear to be significant contributors to the perception of breathlessness in healthy individuals.