Safety of HemaShock® – Effect on Limbs
Stopping arterial blood supply to a limb does not cause sustained injury due to limb ischemia if limited to 120 minutes (Klenermann L. The Tourniquet Manual)
This practice is used daily in orthopedics (about 16,000 cases/day) by using an Esmarch bandage, pneumatic tourniquet or the HemaClear®.
The effects of ischemia on a tissue vary depending on the oxygen and high energy compounds stores, the level of activity o, tissue, which determine the oxygen and metabolites consumption and the threshold for functionality cessation. In addition, the tissue capacity to generate ATP from anaerobic metabolism is important.
There is a large variability in all parameters between tissues. For example, the cardiac muscle has nearly no reserves of energy/oxygen stores. It extracts more oxygen from the blood flowing through the coronary circulation than any other tissue and is in constant high demand for oxygen and metabolites. The brain also lacks storage and is working hard even when seems idle. The brain has a very low tolerance for low oxygen supply and functionality will decrease or stop very soon after blood supply stops or becomes critically low. Nerves (axons), on the other hand, have little oxygen consumption, particularly when not activated.
Muscles, skin, fat and bone tissues, on the other hand, are much more resistive to blocking of the blood flow into them. Muscles are used to consuming more energy than is supplied to them. Energy is stored in the form of Creatine Phosphate which can easily transfer a phosphate to an ADP molecule and generate an ATP. In addition, oxygen is stored in the muscle as bound to a Heme component of the Myoglobin which can dissociate and become available when the tissue PO2 falls below 10 or so mm Hg. Also, there are some ATP stores available. Once the muscle PO2 falls sufficiently, glycogen stores are converted to glucose and anaerobic metabolism becomes active.
It should be noted that all the enzyme systems that are needed for these metabolic pathways are readily expressed in muscles. They provide energy when the muscles are active, and are available to prevent ischemic injury for quite some time.
It is generally accepted that blocking the arterial blood flow into a limb is safe for at least two hours. Abstracts shown below are a few of many publications that studied this issue in animal and human experiments.
General Information About the Regulatory Status of HemaShock®
HemaShock® is intended for use in patients whose systolic blood pressure is pathologically low (i.e. less than 80 mm Hg in adults) due to Hemodynamic Shock or Circulatory (Cardiac) Arrest. HemaShock® shares technology with the Surgical Exsanguination Tourniquet manufactured by OHK as HemaClear® (www.HemaClear.com) which has been cleared for use in many countries around the world. The following is information on the regulatory status of the device in various countries. Should you have any questions, please contact us.
The device is classified as Class I, based on Annex IX, Rule 4 of the Medical Directive 93/42/EEC.
The Surgical Exsanguination Tourniquet was cleared by the FDA in 2002. The HemaShock® FDA clearance needs a further submission.
Ann Surg. 2009 Jan;249(1):1-7. KraghJF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE, Salinas J, Holcomb JB. Source: US Army Institute of Surgical Research,
J Trauma. 2008 Feb; 64(2 Suppl):S28-37; discussion S37. BeekleyAC, SebestaJA, BlackbourneLH, Herbert GS, KauvarDS, Baer DG,Walters TJ, MullenixPS, Holcomb JB; 31st Combat Support Hospital Research Group.
Ann Chir Gynaecol. 1978;67(6):210-3. SantavirtaS, KausteA, RindellK The duration of tourniquet ischaemia was recorded in 1000 consecutive operations on extremities under a bloodless field, the average
J Trauma. 2008 Feb;64(2 Suppl):S38-49; discussion S49-50. KraghJF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE, Salinas J, Holcomb JB. Source: US Army Institute
J Bone Joint Surg Br. 1980 Aug; 62(3):385-8. KlenermanL, BiswasM, HulandsGH, Rhodes AM. The effect of the application of a tourniquet to a limb and the
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