Noninvasive Arterial Studies Including Transcutaneous Oxygen Pressure Measurements with the Limbs Elevated or Dependent to Predict Healing After Partial Foot Amputation

Abstract

Objective 

Noninvasive arterial studies have been used to determine level of amputation. The objective of this study was to examine each component of the noninvasive arterial studies to determine optimal cut points to predict healing and to evaluate whether physiologic maneuvers could improve the utility of transcutaneous oxygen pressure (TcPO₂) values to predict healing of partial foot amputation.

Design 

The authors conducted a retrospective, observational study of 307 patients who underwent partial foot amputation and had noninvasive arterial studies in the perioperative period.

Results 

The TcPO₂ values were significantly predictive of healing. Specifically, a cut point TcPO₂ value of 38 mm Hg had a sensitivity and a specificity of 71% for predicting healing or failure. The optimal cut point was mostly unaffected by patient characteristics. The addition of noninvasive arterial studies recorded in a position with the limb elevated improved prediction in the subgroup with supine TcPO₂ values of 38 mm Hg or lower.

Conclusions 

The findings of this study validate previous reports and confirm that TcPO₂ measurements are valuable to more accurately determine the correct amputation level and, in turn, obtain better outcomes. TcPO₂ measurements may provide better prognostic value than do ankle-brachial indices for healing after partial foot amputation. TcPO₂ measurements are useful but should not be used in isolation to make treatment decisions regarding amputation level.