Abstract: A solution is described that can be used to maintain the patency of an I.V. catheter or other vascular access device having a lumen. The density and osmolarity of the solution are adjusted so that the density and osmolarity of the solution are approximately equal to the density and osmolarity of whole blood in a patient. The solution can be injected into the lumen of the vascular access device to prevent blood from the patient from entering the lumen.

Abstract: A circuit breaker having an arc stack assembly that provides a longer arcing path resulting in decreased restriking characteristics during an interrupt cycle. The arc stack assembly has approximately parallel metal arc plates mounted in insulating sides. At the top of the arc stack assembly is an upper runner with a tail curving downwards to end near the uppermost arc plate. The arc horn has a prong that moves through the arc stack assembly and also through a groove in the upper runner. The tolerance between the arc and the upper runner is very close to facilitate transfer of the arc to the upper runner.