Hypothermia Therapy Protects the Brain During Surgery

An endovascular temperature-control system uses therapeutic hypothermia in patients with cerebrovascular problems to minimize the high risk of stroke and ischemic brain damage during and after surgery.

The InnerCool endovascular Celsius control system is intended for use in inducing, maintaining, and reversing mild hypothermia in neurosurgical patients, both in surgery and in recovery or intensive care unit (ICU). The system can also be used in cardiac patients in order to achieve or maintain normal body temperatures during surgery and during recovery and intensive care, and as an adjunctive treatment for fever control in patients with cerebral infarction and intracerebral hemorrhage.

The system consists of a disposable endovascular heat-transfer catheter, administration cassette, and a console. The distal portion of the catheter (10.7F and 14F) has a flexible, metallic temperature control element (TCE) that is cooled or warmed by sterile saline circulated within it from the Celsius control console. The administration cassette connects the catheter to the console, maintaining the sterility of the saline conduit. The TCE does not expand inside the body so that the outer diameter of the TCE will remain consistent throughout the entire cooling/warming procedure, unlike balloon based cooling systems that expand to outer diameters of 24F-47F during use. The TCE has a proprietary surface of alternating helices that induces mixing and significantly enhances heat transfer directly with the blood flowing in the inferior vena cava. In addition, the use of a flexible metal heat exchanger optimizes heat transfer due to the high thermal conductivity of metal. The flexibility of the TCE is achieved through uniquely designed segmented bellows joints. The catheter can also be placed in an operating room or ICU setting without the need for continuous fluoroscopy. The TCE and catheter are coated with a heparin coating that is covalently bonded to the surface of the catheters through a proprietary process; this covalent bonding ensures a more durable, active heparin coating compared to the short-lived nature of ionically bound heparin coatings.

The proprietary Accutrol catheter contains an integrated temperature sensor, which can accurately determine the patient's core body temperature within 0.1 degree Celsius of pulmonary artery temperature. This eliminates the need to place bladder or rectal probes, which can be slow to react to actual decreases in core body temperature. Temperature control at target temperature is very tight and the algorithm allows for gradual rewarming times, which can be programmed from 3-24 hours. The flexible metallic temperature control element and a built-in temperature feedback sensor are housed inside the catheter to provide fast and precise patient temperature control. The Celsius Control System is a product of Cardium Therapeutics (San Diego, CA, USA), and has been approved by the U.S. Food and Drug Administration (FDA).

"InnerCool's endovascular systems are well designed to meet the high performance needs of the operating room,” said Christopher J. Reinhard, Chairman and CEO of Cardium Therapeutics and InnerCool Therapies. "We believe our low-profile, high-performance endovascular cooling system has the capacity to rapidly achieve and maintain cooling of patients undergoing these critical brain surgeries.”

"Although the precise mechanism of mild cooling's protective effect on the brain is unclear, it appears to blunt the detrimental cascade of events at the cellular level that occurs during the minutes, hours, and sometimes even days after an adverse neurologic event,” commented Gary Steinberg, M.D., chairman of the department of neurosurgery at Stanford University School of Medicine (Palo Alto, CA, USA).


Related Links:
Cardium Therapeutics
Stanford University School of Medicine