title: Does depth of the frontal sinus affect near-infrared spectroscopy measurement?
abstract: Near-infrared spectroscopy (NIRS) is a non-invasive method that reflects real-time cerebral oxygenation (rSO2) by the use of two adhesive optodes placed on the forehead of the patient. Frontal sinuses vary anatomically and a large frontal sinus might compromise the NIRS signal since the NIRS optodes are placed at the skin surface superficial to the underlying frontal sinus. The aim of this case-series was to elucidate whether there is a difference in the obligate changes in rSO2during cardiac surgery between patients with a small as opposed to a large anterior-posterior distance of the frontal sinus based on magnetic resonance imaging. Two matched groups with small (n = 5) vs. large (n = 5) frontal sinus (3.2 vs. 18.1 millimeters) in this case-series showed no difference in obligate changes of rSO2(p = 0.54).
authors.affiliation: 1 Department of Cardiothoracic Anesthesiology, Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Frederik
authors.initials: F
authors.lastname: Holmgaard
authors.affiliation: 1 Department of Cardiothoracic Anesthesiology, Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anne G
authors.initials: AG
authors.lastname: Vedel
authors.affiliation: 2 Department of Radiology, Diagnostic Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Annika
authors.initials: A
authors.lastname: Langkilde
authors.affiliation: 1 Department of Cardiothoracic Anesthesiology, Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jens C
authors.initials: JC
authors.lastname: Nilsson
authors.affiliation: 1 Department of Cardiothoracic Anesthesiology, Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Hanne Berg
authors.initials: HB
authors.lastname: Ravn
keywords: cardiac surgery; cerebral oximetry; frontal sinus; magnetic resonance imaging; near-infrared spectroscopy; signal interference; sinus frontalis