Thursday, 18 August 2011

T 1680/08 – Iron Lung

The “White Book”, in its paragraph I.B.4.4 makes the following statement:
In G 1/07 the Enlarged Board emphasised the difficulty of providing a definition of the term “treatment by surgery.” The boards of appeal would be better suited to define the boundaries of a more narrowly construed concept of “treatment by surgery” in situations other than the one underlying the referral. The boards of appeal may choose a similar case-by-case approach with regard to the concept of treatment by therapy.” (my emphasis)
The present decision is such a post-G 1/07 decision. It deals with a method for determining pressure levels of a lung ventilated by an artificial ventilator.

To be more precise, claim 1 of the main request before the Board read :
1. Method for determining airway pressure levels at which certain lung conditions of a lung ventilated by an artificial ventilator occur, comprising the steps of:

a) obtaining data samples of the CO2 concentration of the expired gas over a single breath,

b) selecting a plurality of data samples from said obtained data samples,

c) calculating a mean tracing value being sensitive to changes of alveolar dead space on the basis of said selected data samples,

d) repeating steps a), b) and c) for obtaining a plurality of mean tracing values, and

e) changing the airway pressure of the artificial ventilator, wherein from the observation of the resulting course of the plurality of calculated mean tracing values the airway pressure level at which alveolar opening or lung overdistension or lung open condition or alveolar closing occurs is detected.
The patentability assessment raises interesting questions. Traditionally, it was held that therapy relates to the treatment of a disease in general or to a curative treatment in the narrow sense as well as the alleviation of the symptoms of pain and suffering (see e.g. T 144/83 [3]). Subsequent decisions have somewhat extended this definition. See, for instance, T 24/91 [2.7], which dealt with a treatment for myopia:
The meaning of the term “therapy” is not restricted to curing a disease and removing its causes. Rather, this term covers any treatment which is designed to cure, alleviate, remove or lessen the symptoms of, or prevent or reduce the possibility of contracting any disorder or malfunction of the human or animal body.
But what about keeping a person alive? Does this qualify as therapy? Is death an illness or a disorder of the human body? Or is the above definition still too narrow?

[2] Pursuant to the transitional provisions relating to the Act revising the EPC of 29 November 2000 as decided by the Administrative Council on 28 June 2001, A 53 applies to European patent applications pending at the time of its entry into force, and thus to the application under dispute in the present case.

[2.1] Claim 1 refers to a method for determining airway pressure levels at which certain lung conditions of a lung ventilated by an artificial ventilator occur. The aim of the method is to determine the pressure levels at which alveolar opening or lung over distension or lung open condition or alveolar closing (hereinafter called relevant pressure levels) occur. The knowledge of these relevant pressure levels for an ailing lung is important to be able to determine the ventilator settings for the optimal, most efficient, ventilation of the patient and most efficient recruitment manoeuvre.

In essence the method consists of connecting the patient to the artificial ventilator, changing (increasing or decreasing) the airway pressure of the artificial ventilator step by step and for each of them calculating a plurality of mean tracing values being sensitive to changes in the dead space on the basis of a plurality of data samples of the CO2 concentration of the expired gas over single breaths, from which the relevant pressure levels can be determined. This method is explained in details in the description of the patent application.

It is however immediately apparent that the above method requires the patient to be connected to the artificial ventilator in order to apply pressure to its lungs and to measure the concentration of CO2 in the expired gas. It is also apparent that each pressure level applied to the lungs of the patient by the artificial ventilator when the airway pressure is changed according to the claimed method is not in any way superimposed on a “normal” ventilation pressure, but is the only pressure actually applied to the patient’s lungs. In other words, the method is not applied on top of any normal artificial ventilation of the patient but during the ventilation phase in which the method is carried out it is the only artificial ventilation effectively applied to the patient. Therefore this, so to say, testing phase is just as vital for the survival of the patient than any other normal artificial ventilation.

It follows that the ventilation phase during which the method is executed cannot be distinguished from the normal artificial ventilation applied to the patient.

Further, the step of changing (increasing or decreasing) the airway pressure of the artificial ventilator in order to determine the relevant pressure levels cannot be distinguished from what a medical doctor would do in order to adapt an artificial ventilation to a given patient. As a matter of fact, the same parameter, namely the airway pressure, which is used to adapt or adjust a normal artificial ventilation to a given patient, is changed when the claimed method is carried out.

It is further to be noted that the claimed method cannot be considered as a momentarily short change of the ventilation parameters without any influence on the ongoing therapy. As a matter of fact, the claim defines neither any restrictive period of time for the measurements nor any specific intensity of the airway pressure changes. And according to the description of the specific embodiment (falling under the scope of the claim), in particular in relation to Figures 2 and 8, the detection phase extends over several tens of breaths, so that this period of time is clearly not insignificant but part of the ongoing therapy time.

Thus there is a functional and indissociable link between the claimed method and any artificial ventilation practised on a connected patient. It is indisputable that artificial ventilation is a therapeutic method because it aims at keeping the patient alive.

Whilst it is admitted that the primary intention of the appellant was not to protect a method for treatment but a method for determining the relevant pressure levels, the Board is of the opinion that this is of little importance since the Enlarged Board has confirmed in G 1/07 that the presence of a single therapeutic or surgical step is sufficient to exclude the method from patentability:
“... in the EPC revision the European legislator deliberately maintained the exclusions under A 52(4) EPC 1973 in the now A 53 c). Thereby the principle has been confirmed that medical and veterinary practitioners’ freedom to use the best available treatments to the benefit of their patients uninhibited by any worry that some treatment might be covered by a patent is protected by excluding these activities from patentability. Excluding from patentability also multi-step methods which comprise or encompass a therapeutic or a surgical step serves to give full effect to that legislative purpose. Therefore, the principle developed in the jurisprudence that the presence of one therapeutic or surgical step in a multi-step method excludes that method from patentability is not only formally justified by the fact that the exclusion under A 53 c) does not contain any limitation as to the defined methods being excluded only when claimed as such. More importantly, it is also justified as to substance, i.e. it serves to enable achieving the legislative purpose served by the exclusion.”(emphasis added).
For the above reasons the Board considers that the claimed method falls under the exclusion of A 53(c).

[2.2] The appellant submitted that the present method did not cure any particular disease, and therefore did not qualify as therapy. The Board does not share this opinion because, as already mentioned above, the present method cannot be distinguished from normal artificial ventilation, the very first aim of which is to keep an anesthetised patient alive, which clearly must be considered as a therapeutic treatment since it avoids the death of the patient by artificially maintaining respiration.

The appellant further submitted that step e) introduced a malfunction in order to determine certain lung conditions. According to the wording of this feature, it requires changing the airway pressure of the ventilator and, as already mentioned above, such airway pressure changes belong to the normal activities of a doctor when adapting the ventilation conditions to the patient. Hence, any step by step increase or decrease of airway pressure when applying the method will necessarily merge with values used for the ventilation therapy itself. Therefore it is irrelevant whether the doctor uses the limit pressures levels for the ongoing therapy or not.

The appellant further submitted that case T 1102/02 should apply by analogy, the claimed method also being a test phase. The aim of the invention in that case was to determine the influence of the delivery tubing on the gas flow pattern delivered to the patient in order to correct the operating parameters of the artificial ventilator and to make sure that the gas flow pattern effectively delivered to the patient corresponded to the desired flow pattern, i.e. the aim was to optimise the flow of gas delivered by the delivery device. The present invention differs because it aims at detecting relevant lung conditions of a particular patient for him to benefit most from the ongoing artificial ventilation. As previously mentioned, in the present invention the testing phase runs over tens of breathing cycles, as shown for example in Figures 2 or 8, so that the said phase cannot be distinguished from the normal artificial ventilation.

The appellant further submitted that a medical doctor would never be hampered by the claimed method as it was executed by a computer. The EPC excludes from patentability any methods of treatment by therapy in general. This has been confirmed by the Enlarged Board in G 1/07 []
“… There is, however, no term in A 53 c) which would allow concluding that hampering of the practitioner’s freedom is a prerequisite for the exclusion to apply in the individual case considered. The only condition defined in A 53 c) for a claim to be excluded from patentability is that it contains subject-matter being a method for treatment of the human or animal body by surgery or therapy or a diagnostic method. If so, it is excluded from patentability and it is then irrelevant whether in the individual situation under consideration a medical practitioner would or could infringe the claim.”
Finally the appellant submitted that the present case is comparable to that in T 245/87 and should therefore be allowed.

In case T 245/87 the method is for measuring the flow of liquid passing through a tubular element which can, among other things, belong to an implantable device for controlled drug administration. In order to measure the flow rate, the electrical resistance of the flowing liquid is measured between two points. It is thus clear that the measuring method has no influence whatsoever on the flow rate per se with which the liquid is administered to the patient. The present method is quite different, since the airway pressure “administered” to the patient under artificial ventilation has to be changed in order to determine the relevant pressure levels. In the present method, again, an obvious functional link exists between the claimed method and the therapy applied to the patient.

The main request was rejected. The case was finally remitted to the Examining Division, based on auxiliary request 2, which only comprised apparatus claims.

I find it helpful to compare the above findings to post-G 1/07 decision T 992/03, where Board 3.4.02 found that the claimed method for MR imaging the pulmonary and/or cardiac vasculature of a subject, using dissolved-phase polarized Xenon gas was patentable because 
“the method claims are not left to encompass the step of delivering polarised 129Xe gas to a subject, which step may have a surgical character at least if it is carried out by an injection.”
In the MR imaging case, it is possible to distinguish the imaging method from the (surgical) injection step and to consider it separately. In the present case, if my understanding is correct, this distinction is not possible because the claimed method is inextricably linked to the (apparently therapeutical) ventilation method.

BTW, the Board found it self-evident that maintaining life is a therapeutic activity, and this sounds reasonable indeed. However, this understanding would call for a new definition of therapy because the definitions provided so far (see above) appear to be too narrow.

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