In patients >20 years post-carotid body resection, hypoxia augmented heart rate and slightly depressed stroke volume and total peripheral resistance without appreciable changes in blood pressure.
Observational
How does carotid body resection affect long-term respiratory and circulatory responses to hypoxia in humans?
Long-term follow-up of carotid body-resected patients reveals that the carotid body reflex predominantly controls vascular activities, while the pulmonary inflation reflex dominates cardiac activities in humans.
The respiratory and circulatory activities of patients who underwent carotid body resection (CBR) more than two decades ago were reviewed. No significant ventilatory response to continuous hypoxia was observed. However, in response to stimulation of peripheral chemoreceptors, transient hyperventilation occurred before hypoxemic blood arrived at the central nervous system (single-breath test), which indicated the presence of weak peripheral chemosensitivity. Because of this slight residual peripheral chemosensitivity, which was found shortly after the operation and apparently remained more or less unchanged for greater than 20 years, peripheral chemoreceptor activity, which has been reported in other animal species, does not seem to have returned. Delayed hypoxic hyperventilation reported in dogs and cats with CBR was not observed. Hypoxia significantly depressed the ventilatory response to CO2, but the delayed ventilatory depression with time that has been demonstrated in normal subjects did not occur. In our circulatory studies, hypoxia augmented the heart rate and slightly depressed the stroke volume and total peripheral resistance in the systemic circulation but induced no appreciable changes in arterial blood pressure or cardiac output. We used these results to partition the relative contributions to the overall circulatory response of carotid body stimulation, pulmonary inflation, and other modifying influences. From these calculations, it was inferred that the carotid body reflex plays a dominant role in vascular activities whereas the pulmonary inflation reflex dominates in cardiac activities in humans.
Yasuhiro Honda (Wed,) conducted a observational in Carotid body resection. Carotid body resection vs. Normal subjects was evaluated on Respiratory and circulatory activities (ventilatory response to hypoxia/CO2, heart rate, stroke volume, total peripheral resistance). In patients >20 years post-carotid body resection, hypoxia augmented heart rate and slightly depressed stroke volume and total peripheral resistance without appreciable changes in blood pressure.
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