The aim of a study published in The Journal of Pediatrics was to evaluate whether equal volumes of oral rehydration solution (ORS) or intravenous (IV) saline render similar improvements in cardiovascular status during controlled orthostatic challenge, when administered to subjects with postural tachycardia syndrome (POTS) with orthostatic intolerance.

Here, the neurovascular response to fluid loading during orthostatic stress was assessed using lower body negative pressure (LBNP)—in 10 subjects with POTS with orthostatic intolerance and 15 controls—and on subsequent days before and 1 hour after IV saline infusion or ingestion of ORS.

The results revealed that individuals with POTS exhibited reduced tolerance to LBNP than controls. In POTS, following ORS, cerebral blood flow velocity (CBFv) was significantly higher than that with no treatment, at -45 mm Hg. However, fluid loading did not show any advantage in controls. Nonetheless, subjects with POTS experienced a significant improvement in orthostatic tolerance after both, saline infusion and ORS.

It was concluded that the maintenance of CBFv may have resulted in improved short-term orthostatic tolerance exhibited by subjects with POTS following ORS administration. Thus, ORS is a convenient, safe and effective therapy for short-term relief of orthostatic intolerance.

Source: The Journal of Pediatrics. 2019 Nov;214:96-102.