The purpose of this research study is to measure rate of decline and pattern of tissue oxygenation using the device, ViOptix T.Ox.

ViOptix probes will be secured to the arm and hand. The recording process on the ViOptix machine will begin and obtain baseline StO2 levels for 5 minutes. After 5 minutes, a blood pressure cuff will be inflated on one arm. This blood pressure cuff will be left inflated for 10-20 minutes. Every 2 minutes a pulse check or doppler exam will be performed at your wrist. Last, the cuff will be deflated and the you will be free to leave the study room.

The rate of decline and pattern seen in tissue oxygenation as quantified by a NIRS device (ViOptiox T.Ox) can be quantified and described by a mathematical model which will allow earlier detection and identification of venous congestion in tissue. The vascular occlusion test has been established as a safe and accurate model to induce various states of vascular insufficiency and occlusion. Specifically the vascular occlusion test has been demonstrated to be an accurate model for inducing venous insufficiency on awake and aware patients. This study will aim to analyze the StO2 data output of the ViOptix in order to establish the earliest signs of tissue failure in various states of vascular compromise.

The purpose of this research study is to measure rate of decline and pattern of tissue oxygenation using the device, ViOptix T.Ox. The data collected will be used to formulate a mathematical model which will allow earlier detection and identification of venous congestion in tissue. Identifying these specific patterns will help to establish an evidence-based approach in recognizing specific problems and patterns associated with tissue compromise that can guide physicians to consider earlier flap salvage measures.

Inclusion Criteria:

• Age 18 - 65 volunteers

Exclusion Criteria:

• Subjects with a history of major cardiac disease, peripheral vascular disease including (vascular insufficiency), Raynaud syndrome, blood dyscrasias, pain syndromes, neurologic conditions, major upper extremity soft tissue trauma or previous vascular injury

Each participant was in the study and monitored for adverse events for approximately one hour on the day the study activities occurred.