Augmented Biphasic Breathing Using Sniff and an Oral Positive Expiratory Pressure Device (Sniff-PEP) in Fontan Patients

The use of an oral positive expiratory pressure device (oPEP) with sniff breathing (Sniff-PEP) mimics biphasic ventilation. Biphasic ventilation increases pulmonary blood flow and cardiac output in Fontan patients. The aim of this study was to assess the effect of Sniff-PEP on Fontan flow velocities. A single-center, pilot, prospective study was carried out in 15 subjects with Fontan circulation enrolled to use the oPEP device for 1 month. Subjects were instructed on Sniff-PEP and to use the device for 10–15 min 3–4 times a day. Measurements of flow velocity and cardiac output were measured via echocardiogram and quality of life assessments were performed at baseline and 4–6 weeks later. The mean age at enrollment was 19.9 ± 8.7 years (age range of 10–37 years). 7 patients (47%) had dominant left ventricle and 8 (53%) had an open fenestration. There was a statistically significant increase in flow velocities in the hepatic vein from 27.5 ± 7.6 to 35.1 ± 11.3 cm/s (p = 0.003), left pulmonary artery from 51.6 ± 16.6 to 57.6 ± 21.1 cm/s (p = 0.01), and right pulmonary artery from 43.1 ± 14.2 to 45.8 ± 17.2 cm/s (p = 0.04). With chronic use, the mean fenestration gradient slightly decreased from 4.5 ± 1.6 to 4.1 ± 1.9 mmHg but the difference was not statistically significant (p = 0.14). oPEP device therapy increased flow velocity in several areas in the Fontan circulation with acute use. Further studies are needed to assess the effects long term.

Clinical Trial Registration: URL: https://clinicaltrials.gov. Unique identifier: NCT03251742.