Study: NCT01319630

Intervention type: DEVICE
Intervention: Sidestream Dark Field (SDF)
Description: SDF will be applied to the sublingual microvascular network with a 5X objective providing a 167X magnification.~After the removal of saliva and other secretions using gauze, the device will be gently applied (without any pressure) on the lateral side of the tongue, in an area approximately 1.5-4 cm from the tip of the tongue. Five sequences of 20 secs each from different adjacent areas will be recorded using a computer and a video card and stored under a random number for later analysis. This will be done at baseline and then 1 hour after Fluid bolus.

Intervention type: DEVICE
Intervention: Sidestream Dark Field (SDF)
Description: SDF will be applied to the sublingual microvascular network with a 5X objective providing a 167X magnification.~After the removal of saliva and other secretions using gauze, the device will be gently applied (without any pressure) on the lateral side of the tongue, in an area approximately 1.5-4 cm from the tip of the tongue. Five sequences of 20 secs each from different adjacent areas will be recorded using a computer and a video card and stored under a random number for later analysis. This will be done at baseline and then 1 hour after Fluid bolus.

Intervention type: DEVICE
Intervention: Sidestream Dark Field (SDF)
Description: SDF will be applied to the sublingual microvascular network with a 5X objective providing a 167X magnification.~After the removal of saliva and other secretions using gauze, the device will be gently applied (without any pressure) on the lateral side of the tongue, in an area approximately 1.5-4 cm from the tip of the tongue. Five sequences of 20 secs each from different adjacent areas will be recorded using a computer and a video card and stored under a random number for later analysis. This will be done at baseline and then 1 hour after Fluid bolus.

Intervention type: DEVICE
Intervention: Near Infrared Spectroscopy (NIRS)
Description: Tissue oxygen saturation (StO2) will be measured by a tissue spectrometer, a noninvasive tool, which uses reflectance mode probes to measure scattering light reflected at some distance from where the light is transmitted into the tissue. The NIRS probe will be placed on the skin of the thenar eminence and a sphygmomanometer cuff will be wrapped around the arm over the brachial artery. After a 3-min period to stabilize the NIRS signal, arterial inflow will be stopped (VOT) by inflating the cuff to 50 mmHg above the systolic arterial pressure. After 3 min of ischemia, cuff pressure will be released, and StO2 recorded continuously for another 3 min period (reperfusion period=Reactive Hyperemia).This will be done at baseline and then 1 hour after fluid bolus.

Intervention type: DEVICE
Intervention: Near Infrared Spectroscopy (NIRS)
Description: Tissue oxygen saturation (StO2) will be measured by a tissue spectrometer, a noninvasive tool, which uses reflectance mode probes to measure scattering light reflected at some distance from where the light is transmitted into the tissue. The NIRS probe will be placed on the skin of the thenar eminence and a sphygmomanometer cuff will be wrapped around the arm over the brachial artery. After a 3-min period to stabilize the NIRS signal, arterial inflow will be stopped (VOT) by inflating the cuff to 50 mmHg above the systolic arterial pressure. After 3 min of ischemia, cuff pressure will be released, and StO2 recorded continuously for another 3 min period (reperfusion period=Reactive Hyperemia).This will be done at baseline and then 1 hour after fluid bolus.

Intervention type: DEVICE
Intervention: Near Infrared Spectroscopy (NIRS)
Description: Tissue oxygen saturation (StO2) will be measured by a tissue spectrometer, a noninvasive tool, which uses reflectance mode probes to measure scattering light reflected at some distance from where the light is transmitted into the tissue. The NIRS probe will be placed on the skin of the thenar eminence and a sphygmomanometer cuff will be wrapped around the arm over the brachial artery. After a 3-min period to stabilize the NIRS signal, arterial inflow will be stopped (VOT) by inflating the cuff to 50 mmHg above the systolic arterial pressure. After 3 min of ischemia, cuff pressure will be released, and StO2 recorded continuously for another 3 min period (reperfusion period=Reactive Hyperemia).This will be done at baseline and then 1 hour after fluid bolus.