title: Real-time continuous estimation of gas exchange by dual oximetry.
abstract: We designed a ventilation-perfusion index (VQI) to estimate venous admixture (Qsp/Qt) in a real-time fashion by simultaneous pulse and pulmonary artery oximetry in 17 patients with acute respiratory failure. Changes in Qsp/Qt were produced by altering the level of continuous positive airway pressure. VQI correlated well with Qsp/Qt (r = 0.78). This contrasts with the poor correlation found between Qsp/Qt and the commonly used oxygen tension based indices such as PaO2/FIO2 (r = -0.51), PaO2/PAO2 (r = 0.47), and PAO2-PaO2 (r = 0.23). The use of dual oximetry to derive a VQI appears to be a reliable and accurate method for real-time assessment of pulmonary gas exchange in patients with acute respiratory failure.
authors.affiliation: Department of Anesthesiology, Ohio State University, Columbus.
authors.forename: J
authors.initials: J
authors.lastname: Räsänen
authors.forename: J B
authors.initials: JB
authors.lastname: Downs
authors.forename: D J
authors.initials: DJ
authors.lastname: Malec
authors.forename: B
authors.initials: B
authors.lastname: DeHaven
authors.forename: W L
authors.initials: WL
authors.lastname: Garner
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002404:Catheterization; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010092:Oximetry / Q000379:methods*; D011175:Positive-Pressure Respiration; D011651:Pulmonary Artery; D012131:Respiratory Insufficiency / Q000097:blood / Q000503:physiopathology; D014692:Ventilation-Perfusion Ratio