Minimally invasive surgery is becoming more common and transfemoral transcatheter aortic valve replacement is offered to older patients with multiple comorbidities. Sternotomy is not required but patients must lie flat and still for up to 2 – 3 hours. This procedure is increasingly being performed under conscious sedation with supplementary oxygen, but hypoxia and agitation are commonly observed.
In this randomised controlled trial, we hypothesised that high-flow nasal oxygen would provide superior oxygenation as compared with our standard practice, 2 l.min-1 oxygen by dry nasal specs. The primary endpoint was the change in arterial partial pressure of oxygen (PaO2) during the procedure. Secondary outcomes included the incidence of oxygen desaturation and patient movements.
A total of 72 patients were recruited. There was no difference in change in PaO2 from baseline using high-flow compared with standard oxygen therapy: median [IQR] increase from 12.1 (10.0- 15.3 [7.2- 29.8]) to 13.7 (10.8- 18.7 [8.5- 32.3]) kPa vs. decrease from 15.5 (12.4- 19.4 [9.2- 22.8]) to 14.2 (11.9- 19.3 [9.7- 22.8]) kPa, respectively (p= 0.087). There was a lower incidence of oxygen desaturation in the high-flow group (p= 0.037). Patients in the high-flow group moved less frequently (p= 0.006) and assigned a significantly higher comfort score to their treatment (p= < 0.001).
This study has demonstrated that high-flow, compared with standard oxygen therapy, does not improve arterial oxygenation over the course of the procedure. There are suggestions that it may improve the secondary outcomes studied.
International Standard Randomised Controlled Trial Number (ISRCTN) 13804861. Registered 15/4/2019. https://doi.org/10.1186/ISRCTN13804861