title: A fibre optic oxygen sensor that detects rapid PO2 changes under simulated conditions of cyclical atelectasis in vitro.
abstract: Two challenges in the management of Acute Respiratory Distress Syndrome are the difficulty in diagnosing cyclical atelectasis, and in individualising mechanical ventilation therapy in real-time. Commercial optical oxygen sensors can detect [Formula: see text] oscillations associated with cyclical atelectasis, but are not accurate at saturation levels below 90%, and contain a toxic fluorophore. We present a computer-controlled test rig, together with an in-house constructed ultra-rapid sensor to test the limitations of these sensors when exposed to rapidly changing [Formula: see text] in blood in vitro. We tested the sensors' responses to simulated respiratory rates between 10 and 60 breaths per minute. Our sensor was able to detect the whole amplitude of the imposed [Formula: see text] oscillations, even at the highest respiratory rate. We also examined our sensor's resistance to clot formation by continuous in vivo deployment in non-heparinised flowing animal blood for 24h, after which no adsorption of organic material on the sensor's surface was detectable by scanning electron microscopy.
authors.affiliation: Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK. Electronic address: federico.formenti@ndcn.ox.ac.uk.
authors.forename: Federico
authors.initials: F
authors.lastname: Formenti
authors.affiliation: Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Rongsheng
authors.initials: R
authors.lastname: Chen
authors.affiliation: Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Hanne
authors.initials: H
authors.lastname: McPeak
authors.affiliation: Biomedical Centre, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic; First Medical Department, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Matejovic
authors.affiliation: Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Farmery
authors.affiliation: Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK. Electronic address: clive.hahn@nda.ox.ac.uk.
authors.forename: Clive E W
authors.initials: CE
authors.lastname: Hahn
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001683:Biological Clocks; D001777:Blood Coagulation / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D003198:Computer Simulation; D005336:Fiber Optic Technology; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D010100:Oxygen / Q000097:blood*; D010313:Partial Pressure; D001261:Pulmonary Atelectasis / Q000097:blood*
chemical_list: D010100:Oxygen
keywords: Cross-over computer control system; Cyclical atelectasis simulation; Optical  sensor