IsoComforterTM: Cold Therapy Technology
In 1991 I had a medical procedure where the surgeon asked me to apply ice to the sutured incision. I quickly experienced the additional pain of the cold ice, the skin surface ice burn, and the mess of the melting ice! In 1992 I invented a cold therapy technology that alleviates all of these ice problems. The innovation centered around the utilization of the extended heat transfer surface area of a black corrugated tube within which ice cold water flows at high rates. This patented design (US Patents 5,336,249; 5,486,207; 5,591,220) delivered a cooling tube surface to a sutured wound at around 44° F, rather than the typical 34°F of direct ice contact. This significantly reduced skin-ice contact pain and eliminated skin burns. The high flow rate of the cold water within the tube increased the heat transfer together with the extended black surface area in accordance to the operating equations of both radiative and convective heat transfer. A typical correlation for forced convection heat transfer is shown below:
Where Nu is the Nusselt number, Re is the Reynolds number (Duρ/µ), and Pr is the Prandtl number (Cp ρ/K). This forced convection governing correlation indicates that the heat transfer coefficient, h, of the water flowing inside the corrugated tube is proportional to the fluid flow velocity to the 0.8 power. Therefore high water flows result in high heat transfer from the higher sutured skin temperature to the ice cold water flow within.
Figure 1 shows the portable water recirculating system. Water is mixed with ice and the water flow is circulated through the corrugated black tube using a submerged high-flow, battery-operated marine pump. The ice cold water flows rapidly through the corrugated tube pad shown in Figure 2. When this pad is firmly placed onto the sutured skin, heat is removed rapidly and efficiently at a skin surface temperature around 44°F.
This technology was developed over a two year period with extensive filed testing in various hospitals. It also achieved FDA approval for use in sterilized, post operation surgeries. It was proven to be very effective in reducing pain killing medication immediately post operation and rapidly achieving significant vaso-constriction which reduces swelling. Large production volumes were realized and is still in current orthopedics applications.