CONVECTION BLOOD WARMING SYSTEM WITH DISPOSABLE FLATTENED TUBE ENVELOPE INCORPORATING PAPERBOARD NEEDLE FOR INSERTING ENVELOPE BETWEEN HEATING PLATES AND EMPLOYING ACTIVE AND PASSIVE INSULATION OF OUTLET FLOW PATH TO PROVIDE NORMOTHERMIC FLUID AT ZERO TO 600 MILLILITERS PER MINUTE

摘要

A thin, flat paperboard inserter or needle which is longer than the blood warmer heating plates is attached to the edge of the flattened tube envelope to enter the very narrow gap between the heating plates. The inserter is fed between the heating plates and advanced to emerge from the other end of the blood warmer where it is grasped and used to pull the envelope into operational position. A high air flow hydrophobic vent with check valve to prevent reverse flow is incorporated into the drip chamber to allow automatic priming and venting of air bubbles. A conductively heated and externally insulated drip chamber holder and a patient intravenous line that is passively insulated by a small annular air space extruded as part of the tube preserve heat in the warmed fluid, improving low flow rate performance. A reusable external heater may optionally be applied to the distal portion of the patient line to provide normothermic fluid to the patient down to essentially zero flow rate.