Work

The acute effect of high-dose supplemental oxygen on haemodynamics assessed by echocardiography in patients with pulmonary vascular disease living in Quito at 2850 m: a randomized, single-blind, placebo-controlled crossover trial

Year: 2024

Type: article

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Aims More than 220 Mio people live at altitudes above 2000 m, many of whom have pre-existing chronic diseases, including pulmonary vascular diseases (PVDs) such as pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH). We investigated the acute effects of high-dose supplemental oxygen on pulmonary haemodynamics assessed by echocardiography in patients with PVD permanently living at 2850 m. Methods and results In a randomized, single-blind, placebo-controlled crossover trial, patients with PVD diagnosed with PAH or CTEPH were allocated to receive 10 L/min supplemental oxygen (FiO2 ≈ 95%) and placebo air administered via a facial mask with reservoir near their living altitude in Quito at 2850 m (FiO20.21, PiO2 ≈ 60% of sea level) in random order with a washout period of >2 h. After >15 min of breathing the respective FiO2, systolic pulmonary artery pressure (sPAP), cardiac output (CO), and other parameters were assessed by echocardiography. Furthermore, radial arterial blood gases were analysed. Twenty-eight patients with PVD (24 females, 26 PAH, age 45 ± 12 years) treated with phosphodiesterase-5 inhibitors (n = 28) and endothelin receptor antagonists (n = 9) were included. With oxygen vs. placebo air, sPAP was 57 ± 23 vs. 68 ± 24 mmHg, mean difference −11 mmHg (−15 to −6 mmHg, P < 0.001), CO was 3.2 ± 0.9 vs. 3.9 ± 1.1 L/min; −0.7 L/min (−0.9 to −0.4 L/min, P < 0.001), while sPAP/CO was unchanged, and the right ventriculo-arterial coupling was increased. PaO2 was 22.5 ± 9.7 vs. 7.6 ± 1.5 kPa; 14.9 kPa (11.4–18.4 kPa, P < 0.001). Conclusion High-dose oxygen therapy in prevalent patients with PVD living near 2850 m significantly lowered sPAP but also CO by a reduced heart rate, resulting in an unchanged pulmonary resistance. Whether longer-term oxygen therapy would improve pulmonary vascular resistance requires further investigation. Registration NCT06084559 URL: https://clinicaltrials.gov/study/NCT06084559.

Source: European Heart Journal Open

DOI: 10.1093/ehjopen/oeae097