Arterial Blood Gas Electrodes pH Electrode PCO2 Electrode PO2 (Clark) Listen Visualize Observe Authored by William A. French. Medically reviewed by Dr. Barbara Erickson, PhD, RN, CCRN. LessonsOverviewCore ValuesIndicationsArterial PunctureRadial ArteryBrachial ArteryFemoral ArteryAllen TestProcedure 1Procedure 2Blood Gas AnalysisBlood Gas Analyzer✓ElectrodesErrorsQuality ControlConclusion Medically reviewed: William A. French