Smith & Nephew in a Vacuum - Court of Appeal construes patent claim with literal interpretation
This article was included in the spring 2011 issue of Innovate - the patents newsletter.
The Court of Appeal has overturned parts of a High Court ruling on the validity and infringement of patents relating to apparatus to assist wound healing (KCI Licensing Inc & others v Smith & Nephew plc & others  EWCA Civ 1260). In doing so, the Court of Appeal has applied its recent ruling on contributory infringement made in Grimme v Scott.
Two patents were in issue, European Patent Nos. 0 777 504 ("'504") and 0 853 950 ("'950"). Both covered apparatus for negative wound therapy whereby pumps are used to create a vacuum over open wounds. This increases the blood flow to the wound, subsequently speeding up the healing process. S&N were appealing a High Court decision that their 'GO' system infringed '504 and that '504 and '950 were valid. KCI cross appealed that there was contributory infringement of '950 under s60(2) Patents Act 1977.
Infringement of '504
Patent '504 relates to a disposable canister connected to the vacuum pump that collects any discharge from the wound. This prevents any contamination of the vacuum pump. An element of the claim in dispute of '504 stated that the apparatus would comprise of a "means for detecting when the canister is substantially filled with liquid and generating a signal which causes the pump to be deactivated". The High Court held that the 'deactivation' requirement of this element was satisfied if the pump merely ceased pumping fluid. In S&N's GO device, once the canister was full, the device detected an increase in the vacuum level of the headspace. The device's motor was then slowed down to maintain a pre-set pressure level and prevent overfilling of the canister. As this meant that the pump was no longer pumping fluid, the High Court had held that the GO device infringed '504.
However, the Court of Appeal disagreed with this interpretation. The device described in '504 incorporated an actual detector. This detector simply switched the vacuum's motor off when fluid in the canister reached a certain level in order to prevent overfilling. The GO device had no such detector; it did not overfill because there was no more room in the canister and the motor was slowed, not because the pump has been deactivated. The Court of Appeal therefore held that the GO device did not infringe this element of '504.
Infringement '950 under s.60(2) Patents Act
Patent '950 relates to the disposable canisters that fit within the apparatus. An element of '950's Claim 1 required a clamp on the inlet tube to prevent the escape of liquid when changing the canister. It was common ground between the parties that the GO device did not include any such clamp. However, KCI alleged contributory infringement under s.60(2) Patents Act 1977, arguing that it was obvious to a reasonable person that the GO device was intended to put the invention into effect by medical staff subsequently adding a clamp. The High Court drew a distinction between the hospitals purchasing the GO devices and the medical practitioners using the devices. At the time of purchase, there was no intention by the hospital to put the invention into effect, and therefore S&N had not infringed under s60(2). This intention only occurred when a medical practitioner decided to add a clamp.
Before the appeal in this case was heard, but after the High Court decision, the Court of Appeal had given further guidance on the scope and interpretation of s60(2) in Grimme v Scott. It was held that the intention to put an invention into effect may be formed at a time later than when the ultimate user first takes possession. This is assuming that the supplier knows, or it is obvious, that some end users will form this intention. The Court of Appeal held that it was probable that at some point a medical practitioner would have clamped the inlet tube when changing a canister, and that this would be known to S&N. Therefore S&N had infringed under s60(2).
Invalidity of '504 and '950
S&N were partially successful in their appeal on the validity of '504 and '950, but only in relation to claim 7 of the '950 patent which was insufficient to save the day for S&N.