Agreement of an inert gas rebreathing device with thermodilution and the direct oxygen Fick method in measurement of pulmonary blood flow.
OBJECTIVE
Inert gas rebreathing is a well established method for the non-invasive measurement of pulmonary blood flow. We tested the agreement in measurement of pulmonary blood flow (Qt rb) by a new inert soluble gas rebreathing device, the Innocor (Innovision, Copenhagen), with bolus thermodilution (Qt td) and the direct oxygen Fick (Qt Fick) method.


METHODS
9 patients pre- and post-cardiac surgery were recruited resulting in 20 sets of measurements overall. Arterial and mixed venous blood samples were collected simultaneously with a thermodilution measurement and rebreathing manoeuvre to measure both V*O2 and effective pulmonary capillary blood flow.


RESULTS
Mean bias (95% confidence limits) was: Qt rb - Qt td 0.01 (+/- 0.42) L/min; Qt rb - Qt Fick + 0.34 (+/-0.59) L/min. The standard deviation of the difference between paired measurements was: Qt td - Qt rb +/- 0.89 L/min; Qt Fick - Qt rb +/- 1.26 L/min.


CONCLUSIONS
Acceptable overall agreement between the Innocor and these reference standards was demonstrated.
Peyton
Philip J
PJ
Department of Anaesthesia, Austin Hospital, Melbourne, Australia. phil.peyton@austin.org.au
Thompson
Bruce
B
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D002302:Cardiac Output; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D005741:Noble Gases / Q000008:administration & dosage; D010100:Oxygen / Q000493:pharmacokinetics; D011182:Postoperative Care; D012039:Regional Blood Flow; D012995:Solubility; D013815:Thermodilution
D005741:Noble Gases; D010100:Oxygen