Can transcutaneous oxygen tension measurement determine re-amputation levels?

Abstract

To review the preoperative transcutaneous oxygen tension (TcPO2) measurements in patients having major lower leg amputation, and also consider the re-amputation rate, wound infection and the definitive level of amputation. A case-control study was performed in a consecutive cohort of 170 patients (1999-2003). Fifty-two patients underwent preoperative TcPO2 measurements (cases) and 118 patients did not (control). Multiple logistic regression analysis was performed to analyse independent risk factors associated with re-amputations. Primary and definitive (in case of a re-amputation) amputation levels were lower in the TcPO2 group, although this did not reach statistical significance. The number of re-amputations in the TcPO2 group was significantly higher: 15 versus 18 patients (p=0.039). Selection of an amputation level with aTcPO2 of 30mmHg resulted in a positive predictive value of re-amputation of 41% and a negative predictive value of 90%. A cut off value of 20mmHg resulted in 41% and 77% respectively. The use of TcPO2 measurements for major amputation level selection resulted in an increased rate of re-amputation. However, there was a trend in gaining a more distal definitive amputation level. Selection of an amputation level solely based on a TcPO2 value is unreliable.