Controlled Contrast Transcranial Doppler and Arterial Blood Gas Analysis to Quantify Shunt Through Patent Foramen Ovale

Abstract

The increase of VM expiratory pressure magnifies the number of microbubbles irrespective of the strain duration. Because the right-to-left shunt classification in PFO is based on the number of microbubbles, a controlled VM pressure is advised for a reproducible shunt assessment. The ABG measurement is not sensitive enough for shunt assessment in stroke patients with PFO.