Transcutaneous pO2 imaging during tourniquet-induced forearm ischemia using planar optical oxygen sensors.
BACKGROUND
Oxygen-dependent quenching of luminescence using transparent planar sensor foils was shown to overcome the limitations of the polarographic electrode technique in an animal model. This method was then transferred to a clinical setting to measure the transcutaneous pO(2) (p(tc)O(2)).


METHODS
In six healthy subjects, a cuff on the upper arm was occluded up to 20 mmHg above systolic pressure and released after 8 min. P(tc)O(2) was measured at the lower arm every 30 s before, during, and up to 20 min after cuff occlusion (40 degrees C applied skin temperature) using luminescence lifetime imaging (LLI) of platinum(II)-octaethyl-porphyrin immobilized in a polystyrene matrix. For validation, the polarographic Clark electrode technique was applied in close proximity, and measurements were conducted simultaneously.


RESULTS
P(tc)O(2) measurements before (70.8+/-19.1 vs. 66.2+/-7.7 mmHg) and at the end of ischemic (2.7+/-1.2 vs. 3.6+/-1.7 mmHg) and reperfusion phases (72.2+/-3.6 vs. 68.4+/-8.9 mmHg) did not differ significantly using the Clark electrode vs. LLI. At both the initial ischemic and the reperfusion phases, the Clark electrode measured a faster decrease or increase, respectively, in p(tc)O(2) because of the oxygen consumption occurring in this method.


CONCLUSIONS
The presented method provides accurate and reproducible p(tc)O(2) values under changing microcirculatory conditions. The lack of oxygen consumption during measurement allows both a more realistic estimation of p(tc)O(2) than compared with the gold standard and permanent use in regions with critical oxygen supply.
Babilas
Philipp
P
Department of Dermatology, Regensburg University Medical Center, Regensburg, Germany. philipp.babilas@klinik.uni-regensburg.de
Lamby
Philipp
P
Prantl
Lukas
L
Schreml
Stephan
S
Jung
Ernst Michael
EM
Liebsch
Gregor
G
Wolfbeis
Otto S
OS
Landthaler
Michael
M
Szeimies
Rolf-Markus
RM
Abels
Christoph
C
D000293:Adolescent; D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007511:Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D055096:Optical Devices; D010100:Oxygen / Q000032:analysis*; D011048:Polarography / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014111:Tourniquets; D014159:Transducers; D055815:Young Adult
D010100:Oxygen