The time interval from the removal of one HemaShock® and the application of another depends on the duration of the ischemia prior to the interval.
Studies in experimental animals show that after one hour of ischemia, 20 minutes are sufficient for recovery of standard bicarbonate, potassium and hydrogen ion levels in the tissues. (Klenerman L. et al.) Systemic and local effects of the application of a tourniquet. (Journal of Bone and Joint Surgery 1980; 62B: 385-388. [Also on page 31 of the Tourniquet Manual by Klenerman]). If the tourniquet is kept on the limb for 2 hours, the data in this study shows that 40 minutes are needed to fully recover HCO3-, K+, and H+ levels. By extrapolation, one may deduce that 30 minutes of recovery is required after 1.5 hours of blood flow occlusion. Combining these data render the Tang method reasonable, although prospective validation is indicated.