Plaintiff CareFusion 303, based in San Diego, which claims a 50-percent share of the IV infusion pump market in the United States alleged that Sigma International, an exclusive supplier of pumps to Baxter, another large supplier of IV infusion pumps in the U.S., infringed CareFusion’s U.S. Patent Number 6,347,553. CareFusion sued Sigma for patent infringement. The ‘553 patent is for a unique force sensor that measures pressure in an IV tube. When a patient rolls over and kinks the tube, the force sensor measures the increased pressure and sounds an alarm so that a doctor or nurse can correct the problem. The force sensor assembly in the ‘553 patent purports to improve sensitivity of the pressure due to a plunger pivotable about an axis and flexible supports beneath the plunger. CareFusion alleged that the force sensor assembly in Sigma’s Spectrum IV infusion pump contained both of these features. Sigma claimed that the ‘553 patent was narrow, limited only to force sensor assemblies where no part of the IV tube was over the centerline of the force sensor. The inventor of the Spectrum IV infusion pump, Matthew Morris, and CareFusion’s expert in infringement, Sigma testified that the ‘553 patent was, in fact, narrow, and did not cover force sensor assemblies where the IV tube was always over the centerline of the force sensor, as is the case in Sigma’s Spectrum IV pump. Additionally, they testified that Sigma’s plunger in the Spectrum IV pump did not pivot about an axis, but rather rested upon a rigid shelf., CareFusion claimed $172 million in lost profit and price erosion damages, as well as sought a permanent injunction that would prevent Sigma from selling Spectrum IV infusion pumps in the future. Defense counsel contended that CareFusion’s damages were speculative and unrealistic. Counsel also contended that the real purpose of the suit was to shut down Baxter’s supplier of IV infusion pumps so that CareFusion could capture market share.