Effects of stellate ganglion blockade on pulmonary artery pressure and sympathetic baroreflex function at high altitude: a case study in treated hypertension.
Ojikutu Q, McCrone J, et al. • Journal of applied physiology (Bethesda, Md. : 1985) • 2026
In a single 44-year-old man with treated hypertension at 3,800 m, right-sided stellate ganglion blockade reduced pulmonary artery systolic pressure and was associated with lower blood pressure variability and altered sympathetic baroreflex and carotid mechanical behavior, suggesting regional sympathetic inhibition may differentially influence pulmonary pressure and baroreflex regulation during sustained high-altitude exposure.
Key Findings
Results
High-altitude exposure increased pulmonary artery systolic pressure, muscle sympathetic nerve activity, blood pressure, and blood pressure variability relative to sea level in this individual with treated hypertension.
Participant was a 44-yr-old man with treated hypertension (single-participant case study).
Measurements were taken at sea level (220 m) and after 5-8 days at high altitude (3,800 m).
Outcomes included PASP, MSNA, beat-by-beat BP, carotid artery diameter, and spontaneous sympathetic baroreflex function.
Results
Right-sided ultrasound-guided stellate ganglion blockade reduced pulmonary artery systolic pressure at high altitude, whereas no meaningful change occurred during the time-control visit.
SGB was performed during high-altitude exposure and measures were compared with subsequent time-control visits.
The abstract reports that PASP fell after SGB while the control visit showed no meaningful change.
The authors describe this as preliminary evidence that regional sympathetic activity may influence pulmonary vascular responses to sustained hypoxia.
Results
Blood pressure variability was lower following SGB than during the time-control visit at high altitude.
Comparison was between the post-SGB assessment and the subsequent time-control visit.
Blood pressure variability had been increased by high-altitude exposure relative to sea level.
Results
The integrative sympathetic arterial baroreflex relationship appeared steeper following SGB.
Spontaneous sympathetic baroreflex function was assessed using the integrative component (relationship between BP and MSNA).
The change was described as 'appeared' steeper, reflecting the descriptive case-study nature of the observation.
Results
The mechanical component of the sympathetic baroreflex showed a greater slope after SGB than during the time-control visit, consistent with altered mechanical baroreceptor transduction.
The mechanical component relates to carotid pressure-diameter behavior.
Carotid artery diameter was measured alongside BP.
Authors interpret this as altered carotid mechanical behavior following unilateral SGB.
Conclusions
The authors conclude that regional sympathetic inhibition may exert distinct influences on pulmonary artery pressure and sympathetic baroreflex regulation during sustained high-altitude exposure in treated hypertension.
The findings are from one participant and are described as preliminary.
The study used a unilateral (right-sided) SGB and a time-control comparison rather than a sham or randomized design.
What This Means
This case study followed one 44-year-old man with treated high blood pressure who spent 5-8 days at 3,800 m. Researchers measured pressure in the lung's artery, nerve activity that controls blood vessels, blood pressure, and how the body's blood pressure reflex worked, first at sea level and then at altitude. Altitude raised lung artery pressure, sympathetic nerve activity, blood pressure and blood pressure variability.
The researchers then temporarily blocked a cluster of nerves on the right side of the neck (the stellate ganglion) with an ultrasound-guided injection. After the block, lung artery pressure fell, whereas it did not change meaningfully at a later comparison visit without the block. Blood pressure variability was also lower, and measures of the blood pressure reflex and carotid artery stiffness-related behavior changed in ways suggesting altered pressure sensing.
Because this involved just one person and no randomization or sham procedure, the results are preliminary and cannot be generalized. This research suggests that sympathetic nerve activity in specific regions may influence lung blood vessel pressure and blood pressure regulation at high altitude, providing ideas for larger studies.
Ojikutu Q, McCrone J, Osei-Boateng C, Wideman C, Roy M, Miners N, et al.. (2026). Effects of stellate ganglion blockade on pulmonary artery pressure and sympathetic baroreflex function at high altitude: a case study in treated hypertension.. Journal of applied physiology (Bethesda, Md. : 1985). https://doi.org/10.1152/japplphysiol.00687.2026