title: Bedside exclusion of clinically significant recirculation volume during venovenous ECMO using conventional blood gas analyses.
abstract: OBJECTIVE
  To investigate prospectively whether blood gas samples drawn from extracorporeal membrane oxygenation (ECMO) cannulae help to exclude at least clinically significant recirculation volumes in patients with acute respiratory failure.
  
  
  METHODS
  Feasibility study.
  
  
  METHODS
  Intensive care unit at a university-affiliated hospital.
  
  
  METHODS
  Ten consecutive adult patients suffering from severe respiratory failure and undergoing ECMO.
  
  
  METHODS
  The drawing (venous) ECMO cannula was placed into the inferior vena cava via a femoral vein, and the oxygenated blood was returned via the right subclavian vein by supraclavicular access directly into the right atrium. Blood gas samples were obtained from both cannulae.
  
  
  RESULTS
  The median arterial oxygen tension (PaO(2)) obtained from the arterial cannula was 537 mmHg (range, 366 to 625 mmHg), the median mixed venous oxygen tension (PvO(2)) drawn from the venous cannula was 42 mmHg (range, 25 to 54 mmHg), which was less than 10% of that observed in the arterial cannula, and also within the physiologic range of PvO(2). The ECMO flow necessary to maintain patients' oxygen saturation above 90% (4.1 L/min; range, 1.95 to 5.8 L/min) was significantly lower than the patients' cardiac output (CO; 6.2 L/min; range, 4.1 to 7.9 L/min; p < 0.001). CONSLUSIONS; We recommend obtaining blood gas samples-immediately after initiation of ECMO-from both cannulae. A PvO(2) within physiologic range and below 10% of PaO(2) rules out any clinically relevant recirculation volume.
authors.affiliation: Department of Internal Medicine I, Intensive Care Unit, University Hospital of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. gottfried.locker@akh-wien.ac.at
authors.forename: Gottfried J
authors.initials: GJ
authors.lastname: Locker
authors.forename: Heidrun
authors.initials: H
authors.lastname: Losert
authors.forename: Peter
authors.initials: P
authors.lastname: Schellongowski
authors.forename: Florian
authors.initials: F
authors.lastname: Thalhammer
authors.forename: Sylvia
authors.initials: S
authors.lastname: Knapp
authors.forename: Klaus F
authors.initials: KF
authors.lastname: Laczika
authors.forename: Heinz
authors.initials: H
authors.lastname: Burgmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Staudinger
authors.forename: Michael
authors.initials: M
authors.lastname: Frass
authors.forename: Manfred
authors.initials: M
authors.lastname: Muhm
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001784:Blood Gas Analysis / Q000379:methods*; D002245:Carbon Dioxide / Q000097:blood; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood; D019095:Point-of-Care Systems; D012131:Respiratory Insufficiency / Q000097:blood / Q000628:therapy*; D013350:Subclavian Vein; D014682:Vena Cava, Inferior
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen