Gavriely N, July 2012.
HemaClear® (HC) is a new device used to prepare a bloodless surgical field in limb surgery. It replaces the Esmach bandage, the pneumatic tourniquet with its accessories and the stockinet. It is an elastic, sterile single-patient use product that has sizes that cover from pediatrics to obese for both lower and upperextremities. Its superiority over the old pneumatic tourniquet method, from the procedure and surgeon’s standpoint is accompanied by important advantages from the overall patient’s safety and wellbeing as seen from the anesthesiologist’s perspective. These include tissue mechanics, circulatory, hematology and logistical aspects which are reviewed below. In particular, the narrow footprint of the HC ring minimizes the amount of tissue under compression, reduces the stress and strain on the nerves and facilitates proximal placement for extended view bleeding-free procedures in mid-shaft femur and humerus/elbow cases. The sterile HC can also be placed close to the surgical incision thereby minimizing the amount of tissue under ischemic conditions. The near-perfect exsanguination prevents blood from being left behind to clot and accumulate cardio-depressive ischemic by-products (CO2, lactic acid, K+) as is manifested by post-tourniquet release shower of emboli and drop in blood pressure seen with the tranditional method. The use of the HC has been shown to reduce the need for post-op blood transfusion in bilateral TKA. Its use can reduce tourniquet time and OR time and the logistics of procurement and pre-op setting up is markedly streamlined.
The usual contraindications of the bloodless field preparation apply to the HemaClear® including the presence of DVT, infection and malignancy in the operated limb. Skin lesions are relative contraindications and peripheral vascular diseases should be viewed with caution and certainly with attempt to cut ischemia time to a minimum. The anesthesiologist should be aware of the fact that the device is designed and factory calibrated to withstand an upper limit of systolic blood pressure (130, 160, 190 mmHg, depending on model). If the patient’s BP rises above the rated level (e.g. due to pain), blood will penetrate the limb causing bleeding and disrupting the surgical procedure. The tourniquet time (in patients with normal circulation) is limited to 120 minutes. A second device can be applied in long procedures after a period of re-perfusion. Correct size and site selection is a shared responsibility with the surgeon. The overall rate of side effects is very small with no reported cases of long-standing tourniquet paralysis. Two cases of possible fat necrosis were reported in obese elderly patients with no consequences.
The HemaClear® is a cardiovascular product that is serving in orthopedic surgeon. As such, full understanding of its mechanics, physiology and clinical implications by the anesthesia team is essential. The material below is a brief review of these aspects.