OBJECTIVE: Evaluation of ideal time for baseline PtcO2 readings in air, elevation test, and oxygen challenge during evaluation of hypoxic wound patients. DESIGN: Retrospective analysis. IRB APPROVAL: Western IRB deemed this study exempt from requiring IRB approval. PATIENTS: 202 patients with lower extremity wounds. METHOD: Patients had PtcO2 measurements using 6 electrodes positioned in 3 paired locations along the limb (above the knee: AK; below the knee: BK; and foot). Measurements were made from each electrode at 7 different time-event occasions: position of limb (supine or elevated), type of breathing gas (sea level air or oxygen), and time of measurement. A total of 8,484 measurements were analyzed by first examining each electrode's data, and then pooling the data for each location pair. MAIN RESULTS: PtcO2 readings for air (10 minutes) were less than air at 20 minutes. Maximal readings were close to the 20-minute mark for AK and BK measurements, and closer to 30 minutes for the foot. Elevation test at 3 versus 5 minutes showed a continuing decline in PtcO2 values. Oxygen challenge readings at 5 and 10 minutes were significantly different: the latter always larger than the former. CONCLUSION: Ideal times for baseline readings, leg elevation test, and oxygen challenge test are at least 20, 5, and 10 minutes, respectively.
OBJECTIVE: Evaluation of ideal time for baseline PtcO2 readings in air, elevation test, and oxygen challenge during evaluation of hypoxic wound patients. DESIGN: Retrospective analysis. IRB APPROVAL: Western IRB deemed this study exempt from requiring IRB approval. PATIENTS: 202 patients with lower extremity wounds. METHOD:Patients had PtcO2 measurements using 6 electrodes positioned in 3 paired locations along the limb (above the knee: AK; below the knee: BK; and foot). Measurements were made from each electrode at 7 different time-event occasions: position of limb (supine or elevated), type of breathing gas (sea level air or oxygen), and time of measurement. A total of 8,484 measurements were analyzed by first examining each electrode's data, and then pooling the data for each location pair. MAIN RESULTS: PtcO2 readings for air (10 minutes) were less than air at 20 minutes. Maximal readings were close to the 20-minute mark for AK and BK measurements, and closer to 30 minutes for the foot. Elevation test at 3 versus 5 minutes showed a continuing decline in PtcO2 values. Oxygen challenge readings at 5 and 10 minutes were significantly different: the latter always larger than the former. CONCLUSION: Ideal times for baseline readings, leg elevation test, and oxygen challenge test are at least 20, 5, and 10 minutes, respectively.