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EAST WINDSOR, NJ, United States

Merrill T.,Rowan University | Merrill T.,Focalcool, Llc
Mechanical Engineering | Year: 2010

Medivance Inc. offers the Arctic Sun system, which has two major components, a cooling console and a series of cooling pads called ArcticGel pads. The console ensures that coolant circulates at the correct temperature for the correct amount of time. An ArcticGel pad consists of three flexible layers so it can conform to the body. The outer layer, not in contact with the patient, insulates the pad so ambient thermal energy does not warm the coolant. The middle layer provides a leak-tight internal coolant flow pathway. Its design involves subtle enhancements or flow obstructions to promote coolant mixing and thin boundary layers - those regions where temperature gradients are greatest inside the coolant flow. The inner layer, in contact with the patient, is made of material that is thin, conductive, and gel-like. Heat transfer conduction rates are directly proportional to conductivity, area, and temperature differences, and inversely proportional to material thickness. Source


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 168.97K | Year: 2005

DESCRIPTION (provided by applicant): Stroke is the leading cause of serious disability in the U.S. While the neuroprotective power of hypothermia has been known decades, our ability to fully harness its protective power has not come easily. The objective of this project is to develop a cooling catheter that can rapidly cool the brain. Existing cooling catheters cool systemically. As a result, 2 factors reduce the effectiveness of hypothermia: 1) the thermal inertia of the whole body delays the time to target temperatures, and 2) the target temperatures are warmer than optimal temperatures because of cardiovascular and infection concerns. Our innovative technology explores another heat transfer augmentation technique that has not been explored: active mixing. Using dynamic heat exchange surfaces instead of static or motionless ones, we intend to create a catheter that meets the necessary cooling requirements while still maintaining adequate blood perfusion. Assuming 20% of U.S. stroke victims are open to hypothermia treatment, the anticipated market for these prototypes is $120-180 million dollars. The specific aims of our Phase I feasibility project are the following: 1) design and build 2 cooling catheter prototypes for in vitro and in vivo testing, 2) test and evaluate the in vitro performance of the prototypes, and 3) test and evaluate the in vivo performance and safety, in terms of vessel damage & hemocompatability. Using a first order heat transfer model and an existing carotid artery hemodynamic model, designs will be transformed into 3D solids and manufactured. In vitro testing will follow on a bench with demonstrated energy balance accuracy. Promising in vitro prototypes will then be used in a pilot animal study to demonstrate feasibility in terms of safety and performance in a large animal. Device performance will be gauged by 3 factors: its ability to cool, its ability to not obstruct blood flow, and its ability to operate safely.


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 207.20K | Year: 2011

DESCRIPTION (provided by applicant): Stroke is the 3rd leading cause of death and number one cause of adult disability in the United States. The primary goal of ischemic stroke treatment is quickly restoring blood perfusion. However, studies have shown that this return of blood flow, while necessary to bettering patient outcome, can cause damage to local tissue. Hypothermia has been shown to decrease this reperfusion injury . The overall goal of this proposed research is to use therapeutic hypothermia to augment the tissue salvage capabilities of existing mechanical clot removal devices that restore perfusion by reducing reperfusion injury. Our proposed device is a cooling guide catheter which will function identically to conventional guide catheters but with blood cooling capabilities to save ischemic tissue at risk of reperfusion injury. Specific Aims: 1.) Design a cooling guide catheter that can be used with existing mechanical clot removal devices and that can quickly reduce target tissue temperatures, 2.) characterize device thermal-fluid performance in an in vitro brain model, and 3.) demonstrate that the cooling catheter can safely and effectively decrease target tissue temperature in a small animal pilot study. To achieve these aims the following willbe performed: thermal-fluid modeling, design input requirements and feasibility points, development of prototype designs, coolant pressure-flow behavior characterization, in vitro thermal-fluid performance testing for each prototype in system that mimicsintracranial blood flow, and in vivo testing demonstrating that rapid localized tissue cooling is feasible and that the catheter is hemocompatibile with no significant damage to vessels or tissue. Relevance: The technological innovation of combining stroketreatment therapies - mechanical clot removal and reperfusion hypothermia - may yield synergistic benefits, resulting in reduced infarct size and improved neurological outcomes compared to outcomes using either technology separately. If fast and safe cooling is shown feasible in Phase I, Phase II would investigate efficacy using an animal stroke model. PUBLIC HEALTH RELEVANCE: Stroke is the 3rd leading cause of death and number one cause of adult disability in the United States. For stroke treatment, quickly restoring blood flow has been shown to improve outcome, although some experts have found reperfusion injury mitigates these benefits. FocalCool, LLC seeks to combine two technologies, thrombectomy and therapeutic hypothermia using a novel coolingguide catheter potentially maximizing the benefit of blood flow restoration while minimizing damaging effects of reperfusion injury.


Merrill T.L.,Rowan University | Merrill T.L.,Focalcool, Llc | Mitchell J.E.,Focalcool, Llc | Merrill D.R.,Focalcool, Llc
Medical Engineering and Physics | Year: 2016

Recent revascularization success for ischemic stroke patients using stentrievers has created a new opportunity for therapeutic hypothermia. By using short term localized tissue cooling interventional catheters can be used to reduce reperfusion injury and improve neurological outcomes. Using experimental testing and a well-established heat exchanger design approach, the ɛ-NTU method, this paper examines the cooling performance of commercially available catheters as function of four practical parameters: (1) infusion flow rate, (2) catheter location in the body, (3) catheter configuration and design, and (4) cooling approach. While saline batch cooling outperformed closed-loop autologous blood cooling at all equivalent flow rates in terms of lower delivered temperatures and cooling capacity, hemodilution, systemic and local, remains a concern. For clinicians and engineers this paper provides insights for the selection, design, and operation of commercially available catheters used for localized tissue cooling. © 2016 IPEM Source


Merrill T.L.,Rowan University | Merrill T.L.,Focalcool, Llc | Merrill D.R.,Focalcool, Llc | Akers J.E.,Focalcool, Llc
Journal of Medical Devices, Transactions of the ASME | Year: 2012

Mild hypothermia has been shown to reduce heart tissue damage resulting from acute myocardial infarction (AMI). In previous work we developed a trilumen cooling catheter to deliver cooled blood rapidly to the heart during emergency angioplasty. This paper describes two alternative designs that seek to maintain tissue cooling capability and improve "ease of use." The first design was an autoperfusion design that uses the natural pressure difference between the aorta and the coronary arteries to move blood through the trilumen catheter. The second design used an external cooling system, where blood was cooled externally before being pumped to the heart through a commercially available guide catheter. Heat transfer and pressure drop analyses were performed on each design. Both designs were fabricated and tested in both in vitro and in vivo settings. The autoperfusion design did not meet a cooling capacity target of 20 W. Animal tests, using swine with healthy hearts, showed that the available pressure difference to move blood through the trilumen catheter was approximately 5-10 mmHg. This differential pressure was too low to motivate sufficient blood flow rates and achieve the required cooling capacity. The external cooling system, however, had sufficient cooling capacity and reasonable scalability. Cooling capacity values varied from 14 to 56 W over a flow range of 30-90 ml/min. 20 W and 30 W were achieved at 38 ml/min and 50 ml/min, respectively. Animal testing showed that a cooling capacity of 30 W delivered to the left anterior descending (LAD) and left circumflex arteries (LCX) of a healthy 70 kg swine can reduce heart tissue temperatures rapidly, approximately 3 °C in 5 min in some locations. Core temperatures dropped by less than 0.5 °C during this cooling period. An autoperfusion design was unable to meet the target cooling capacity of 20 W. An external cooling design met the target cooling capacity, providing rapid (1 °C/min) localized heart tissue cooling in a large swine model. Future animal testing work, involving a heart attack model, will investigate if this external cooling design can save heart tissue. © 2012 American Society of Mechanical Engineers. Source

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