Carbon dioxide for neurogenic orthostatic hypotension in adults: a novel therapy, 2024, Jacquie R Baker et al

Introduction
Neurogenic orthostatic hypotension (nOH) is a hallmark feature of autonomic nervous system failure.1 On standing, people with nOH experience large reductions in blood pressure (≥20/10 mmHg) and debilitating symptoms (e.g. light-headedness, blurred vision, and syncope).1 Current blood pressure therapies have limited efficacy and potentially serious side effects, including supine hypertension,2 creating a strong clinical need for new therapeutic approaches.

Previous studies examining the effects of hypocapnia [i.e. low arterial carbon dioxide (CO2)] on blood pressure have shown that hyperventilation-induced hypocapnia decreases supine blood pressure in nOH patients and can be readily prevented with exogenous CO2.3,4 Whether exogenous CO2 can prevent OH in these patients is unknown. In this proof-of-concept study, we tested the hypothesis that increased inspired CO2 increases standing blood pressure in patients with nOH.

Conclusions
Increased inspired CO2 elevates standing blood pressure in patients with nOH and reduces the duration of OH. These findings support further exploration of CO2 delivery interventions as an acute blood pressure therapy in nOH, potentially improving orthostatic tolerance and preventing syncope, traumatic falls, and, in turn, OH-related hospitalizations.
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