title: Evaluation of the Microstat™ sublingual PCO2 monitor in ambulatory patients.
abstract: Physicians often need to measure arterial PCO2 in clinical practice. Arterial blood gas sampling is typically available only in hospitals and may be unpleasant for patients. Minimally invasive techniques for measuring PCO2 offer the potential for overcoming these limitations. The MicroStat monitor non-invasively measures PCO2 in the sublingual tissues, which should track arterial PCO2 in hemodynamically stable patients. This was a prospective observational study. Patients undergoing routine cardiac catheterization were recruited. Following arterial cannulation, two sequential sublingual PCO2 measurements were taken and a contemporaneous arterial sample was sent for blood gas analysis. For each subject we calculated the mean sublingual-arterial CO2 gradient and the test-retest sublingual PCO2 difference. Twenty-five patients were studied. Mean sublingual-arterial PCO2 gradient was +6.8 mmHg (95 % limits of agreement -3.0 to 16.6 mmHg). Test-retest difference was 3.4 mmHg (95 % limits of agreement -1.1 to 7.9 mmHg), p = 0.11 (Wilcoxon test), repeatability was 11 mmHg. The MicroStat sublingual PCO2 monitor over-estimates arterial PCO2 with wide limits of agreement. Test-retest repeatability was poor. Use of sublingual PCO2 monitoring with the MicroStat monitor cannot currently replace blood gas sampling.
authors.affiliation: Center for Pulmonary Vascular Disease, Divisions of Cardiology, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Room E-222, 3755 Cote Ste Catherine, Montreal, QC, H3T 1E2, Canada. benfox@post.tau.ac.il.|Pulmonary Institute, Rabin Medical Center, Petach Tikva, Israel. benfox@post.tau.ac.il.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Fox
authors.affiliation: Center for Pulmonary Vascular Disease, Divisions of Cardiology, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Room E-222, 3755 Cote Ste Catherine, Montreal, QC, H3T 1E2, Canada. dominique.joyal@mcgill.ca.
authors.forename: Dominique
authors.initials: D
authors.lastname: Joyal
authors.affiliation: Center for Pulmonary Vascular Disease, Divisions of Cardiology, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Room E-222, 3755 Cote Ste Catherine, Montreal, QC, H3T 1E2, Canada. robert.schlesinger@mcgill.ca.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Schlesinger
authors.affiliation: Center for Pulmonary Vascular Disease, Divisions of Cardiology, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Room E-222, 3755 Cote Ste Catherine, Montreal, QC, H3T 1E2, Canada. mark.eisenberg@mcgill.ca.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Eisenberg
authors.affiliation: Center for Pulmonary Vascular Disease, Divisions of Cardiology, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Room E-222, 3755 Cote Ste Catherine, Montreal, QC, H3T 1E2, Canada. david.langeleben@mcgill.ca.
authors.forename: David
authors.initials: D
authors.lastname: Langleben
mesh_terms: D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation* / Q000379:methods*; D002245:Carbon Dioxide / Q000097:blood*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013361:Sublingual Gland / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide
keywords: Blood gas analysis; Carbon dioxide; Comparative study; Patient monitoring; Sublingual region