title: Experiences with continuous intra-arterial blood gas monitoring: precision and drift of a pure optode-system.
abstract: OBJECTIVE
  The utility of continuous intra-arterial blood gas analysis (CBGA) with combined electrochemical and optode sensors has been demonstrated. More recently, a pure optode sensor with a changed sensing element architecture has become available. The aim was to determine the measurement accuracy and long-term stability of the new sensor.
  
  
  METHODS
  A prospective explorative study was performed. Simultaneous measurements of intermittent blood gas analyses (IBGA) (ABL 610, Radiometer, Copenhagen) and CBGA (Diametrics Medical, High Wycombe, Bucks., UK) were compared using Bland-Altman analysis.
  
  
  METHODS
  Twenty-five patients admitted to the ICU and requiring mechanical ventilation for an expected minimum of about 96 h were included.
  
  
  RESULTS
  Mean monitoring time was 106.1 (range 15-231) hours. Bias and precision for PO(2 )were -0.2 kPa (1%)+/-1.8 kPa (9.5%); PCO(2): 0.03 kPa (0.6%)+/-0.44 kPa (9.3%); pH: -0.001 (0.01%)+/-0.04 (0.45%). The sensor showed no change of measurement characteristics during 4 days of measurement. However, in 69 cases continuous monitoring was interrupted (reversible sudden drops of PO(2) measurement) possibly caused by thrombotic deposition and/or sensor bending and accidental sensor retraction.
  
  
  CONCLUSIONS
  The precision and bias of the PCO(2)- and pH-sensing elements were in line with the findings of the older sensor technology. The possibility that the PO(2) optode could offer greater accuracy than the older technology is suggested by comparisons with results reported in previous studies. No sensor drift occurred during long-term measurement over more than 4 days.
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany. matthias.menzel@medizin.uni-halle.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Menzel
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Soukup
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Henze
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Engelbrecht
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Senderreck
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Scharf
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rieger
authors.affiliation: Dept. of Anesthesiology and Intensive Care Medicine, Martin-Luther-University, Magdeburger Strasse 16, 06097, Halle, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Grond
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies