Preamputation evaluation of limb perfusion with laser Doppler imaging and transcutaneous gases.
We studied 31 subjects with severe leg ischemia and 29 age-matched nonischemic control subjects to compare preamputation assessments of leg ischemia using laser Doppler imaging (LDI), transcutaneous partial pressure of oxygen (TcPO(2)), and transcutaneous partial pressure of carbon dioxide (TcPCO(2)). TcPO(2) and TcPCO(2) were evaluated with Novametrix Medical Systems, Inc, monitors (Wallingford, Connecticut) and perfusion (flux) of skin topically heated to 44 degrees C, and adjacent nonheated areas were evaluated with a Moor Laser Doppler Imager (Moor Instruments, Ltd; Devon, England). LDI flux of heated areas, its ratio to nonheated areas, and TcPO(2) (not TcPCO(2)) were lower in ischemic subjects than in control subjects. LDI flux ratio performed better than TcPO(2) in identifying ischemia, with fewer false positive and false negative results. Moreover, LDI flux of heated skin detected a proximal to a distal gradient of perfusion in ischemic subjects, while TcPO(2) did not. LDI was superior to TcPO(2) in discriminating correctly between ischemic and nonischemic skin. The results suggest that an LDI ratio below 5 indicates nonviable skin.
Figoni
Stephen F
SF
Department of Physical Medicine and Rehabilitation, Veterans Affairs Greater Los Angeles Healthcare System (VAGLAHS), Los Angeles, CA, USA.
Scremin
Oscar U
OU
Kunkel
Charles F
CF
Opava-Rutter
Dorene
D
Johnson
Jessica
J
Schmitter
Eric D
ED
Scremin
A M Erika
AM
D000671:Amputation, Surgical / Q000379:methods; D000704:Analysis of Variance; D001785:Blood Gas Monitoring, Transcutaneous; D016022:Case-Control Studies; D006801:Humans; D007511:Ischemia / Q000175:diagnosis* / Q000601:surgery; D017078:Laser-Doppler Flowmetry; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity; D012867:Skin / Q000098:blood supply; D013977:Tibia / Q000098:blood supply* / Q000601:surgery