T 0592/98 05-10-2001

I. The applicant filed an appeal on 12 March 1998 against the decision of the Examining Division to reject the application posted on 14 January 1998. The appeal fee was paid on 13 March 1998 and the grounds for appeal were filed on 22 May 1998.

II. The Examining Division held that claim 1 of the main request did not meet the requirements of Article 52(4) EPC (medical treatment) and that claim 1 of the auxiliary request was not novel over:

D1: A microprocessor-based servo respirator, by Kuo-An Huang, Fargo, North Dakota, 1985.

Parts of this document (the front page and pages 55 and 56) were first submitted by a third party which filed observations with letter of 21 December 1995.

With communication dated 9 February 1996 the Examining Division introduced the document into the procedure and stated that the independent apparatus claim was not inventive having regard to the above cited document (point IV) and that due to document D1 the claims had obviously to be radically reformulated (point VI).

With letter of 26 December 1996, pages 6 to 8, the appellant replied to these objections and stated that pages 55 and 56 were taken out of context as regards the whole document: "The overall document demonstrates that, indeed, it is possible to deliver volume assist and flow assist and that these gains can be made to change automatically in response to the partial pressure of CO2 in an effort to control the partial pressure of CO2. However, nowhere does this reference describe a method of use of volume assist and flow assist...". The letter goes to cite page 39, paragraph 2 of document D1; page 28, paragraph 2; page 129, bottom; Table 6.1, page 130; page 15, line 9; page 28, item 2; page 38, last sentence; page 39, item 1; page 80, lines 8 and 9; page 81, last sentence; page 82, last sentence, page 94, last sentence; page 128, last sentence; page 129, last sentence and Table 6.1, page 130 (see pages 6 and 7 of the letter of responses). Furthermore the applicant stated in the above cited letter that there was already in the specification of the patent in suit, page 5, an acknowledgment of an article by Poon et al which was in essence the same disclosure as was contained in document D1 (page 8 of the response).

With communication of 7 August 1997 the Examining Division pointed out that in its opinion the Poon article did not disclose the same respiratory assisting method as document D1 (page 4 of the communication). The Examining Division further suggested that - in order to facilitate the consideration of its arguments - the applicant should file the missing pages of document D1, because the file still contained only pages 1 (front page), 55 and 56 filed by a third party. In any case pages 55 and 56 were considered by the Examining Division sufficient for destroying the inventive step of the patent in suit (pages 5 to 8 of the communication).

With letter of 20 November 1997 the appellant filed a complete copy of document D1.

On 26 November 1997 oral proceedings were held before the Examining Division. In the minutes of the oral proceedings, page 2, point 6, it is stated that document D1 was accepted by the appellant as being representative of the closest state of the art. The discussion regarding novelty was based only on document D1 and "the representative of the applicant had to acknowledge...that this [i.e. the difference between the claimed invention and the teaching of document D1] was not any constructional difference, but just a different use of the same apparatus, i.e. that the claimed apparatus was not novel over the prior art within the meaning of Article 54 EPC" (page 3 of the minutes). The following written decision to refuse the application was based on lack of novelty having regard to document D1.

In the statement of grounds of appeal filed with letter of 22 May 1998 the appellant brought forward arguments to support the novelty and the inventive step of the patent in suit in relation with document D1 (points 3 and 4). With letter of 6 February 2001 the appellant presented new arguments against the relevance of document D1 (pages 6 to 8). Upon request of the appellant, the Board held oral proceedings on 23. February 2001. In these oral proceedings the appellant for the first time challenged the publication date of document D1. The oral proceedings terminated with the declaration that the Board would further investigate whether or not document D1 had been made publicly available before the priority date of the application in suit. With respect to all other issues the debate was closed.

On 26 February 2001 an enquiry was sent by telefax on behalf of the Board to North Dakota State University requesting information about the exact date on which document D1 was first made available to the public. On 2. March 2001 a reply was received by e-mail containing a declaration that document D1 was published and placed on the shelves of North Dakota State University Library in May 1985. In reply to the communication by the Board of the Board's above cited enquiry, and of the declaration received as reply, the appellant expressed doubts as to whether document D1 formed part of the state of the art. Furthermore, for the first time the appellant stated that the inventor of the application in suit first learned of the thesis (document D1) from Dr Poon, Major Advisor and a signatory to sheet ii of the thesis, in 1991, but that at that time Dr Poon refused his request for a copy. Finally, the appellant expressed his wish to file sworn evidence in support of his assertion that document D1 was not published before the claimed priority.

III. The final requests of the appellant as formulated on 23. February 2001 at the end of the oral proceedings were as follows:

As main request he requested that the decision under appeal be set aside and that a patent be granted on the basis of the main request indicated in point 5 of the Facts and Submissions of the decision under appeal. As first auxiliary request he requested that a patent be granted on the basis of the auxiliary request indicated in said point 5. As second auxiliary request he requested that a patent be granted on the basis of the auxiliary request submitted by telecopy on 22 May 1998. As third auxiliary request he requested that the patent be granted on the basis of the auxiliary request filed on 6 February 2001.

IV. Claim 1 of the main request filed on 26 November 1997 reads as follows:

"A method for controlling gas flow of an apparatus for delivering pressure assist ventilation to a patient, which feeds assist gas in response to respiratory effort of the patient, characterized by the steps of:

a) providing a free flow of gas from a gas delivering system into a pipe;

b) determining the rate and volume of flow of said gas through said pipe;

c) independently amplifying signals corresponding to said determined rate and volume flow;

d) determining assist pressure from said signals by the equation:

Pvent = K1V + K2V',

where Pvent is the magnitude of the pressure assist, K1 is a gain factor applicable to a continuous varying volume signal V which is a fraction of the elastance of the respiratory system, and K2 is a gain factor applicable to a continuously variable flow rate signal V' which is smaller than the resistance at the respiratory system; and

e) sending a command signal to the gas delivery system to generate said assist pressure."

V. Claim 1 of the first auxiliary request filed on 26. November 1997 reads as follows:

"Apparatus for delivering proportional assist ventilation to a patient, comprising

a) means (202) for delivering a free flow of gas to a patient in response to patient inhalatory effort;

b) means (205) operatively connected to said gas delivery means (202) for generating pressure in said free flow of gas in response to an electrical command signal (207);

c) detection means (209) for detecting the instantaneous volume and flow of gas to the patient and for generating a separate electrical signal corresponding in magnitude to each of said detected values (V and V' respectively);

d) externally actionable gain control means (212, 215) for selectively applying amplification to each of said electrical signals; and

e) means (218) for generating said electrical command signal (207) to said pressure generating means (205) in proportion to the sum of said amplified electrical signals corresponding in magnitude to said instantaneous flow and volume in accordance with the equation:

Pvent = K1V + K2V',

where Pvent is the magnitude of the variable assist, K1 is a gain factor applied to said electrical signal by gain control means (215) corresponding to volume V and is a fraction of the respiratory elastance of the patient and K2 is a gain factor applied to said electrical signal by gain control means (212) corresponding to flow V' and is a fraction of the respiratory resistance of the patient."

VI. Claim 1 of the second auxiliary request filed on 22 May 1998 reads as follows:

"Use of apparatus for delivering proportional assist ventilation to a patient, the apparatus comprising

a) means (202) for delivering a free flow of gas to a patient in response to patient inhalatory effort;

b) means (205) operatively connected to said gas delivery means (202) for generating pressure in said free flow of gas in response to an electrical command signal (207);

c) detection means (209) for detecting the instantaneous volume and flow of gas to the patient and for generating a separate electrical signal corresponding in magnitude to each of said detected values (V and V' respectively);

d) externally actionable gain control means (212, 215) for selectively applying amplification to each of said electrical signals; and

e) means (218) for generating said electrical command signal (207) to said pressure generating means (205), wherein said signal is generated in proportion to the sum of said amplified electrical signals corresponding in magnitude to said instantaneous flow and volume in accordance with the equation:

Pvent = K1V + K2V',

where Pvent is the magnitude of the variable assist, K1 is a gain factor applied to said electrical signal by gain control means (215) corresponding to volume V and is a fraction of the respiratory elastance of the patient and K2 is a gain factor applied to said electrical signal by gain control means (212) corresponding to flow V' and is a fraction of the respiratory resistance of the patient, characterized in that the apparatus further comprises:

a) means for inputting data representative of the elastance of the patient;

b) means for inputting data representative of the resistance of the patient; and

c) means for inputting a value corresponding to the fraction of total pressure required to be supplied by the apparatus, whereby K1 is the product of input a) and input c), and K2 is the product of input b) and input c)."

VII. Claim 1 of the third auxiliary request filed on 6. February 2001 reads as follows:

"Ventilator apparatus for delivering pressure assists to a patient in proportion to the instantaneous inhalatory effort Pmus of the patient, the apparatus comprising:

a) means (202) for delivering a free flow of gas to a patient in response to patient inhalatory effort delivering pressure Pmus;

b) means (205) operatively connected to said gas delivery means (202) for generating a pressure Pvent in said free flow of gas in response to an electrical pressure command signal (207);

c) detection means (209) for detecting the instantaneous volume (V) and flow (v) of gas to the patient and for generating respective separate electrical signals corresponding in magnitude to the detected values V and v respectively;

d) command signal generating means (212, 215, 218) comprising;

(i) adjustable gain control means (212, 215) for applying respective amplification to each of said electrical signals according to selected gain factors; and

(ii) final command signal generating means (218) disposed to receive said amplified electrical signals, to generate a final electrical command signal and to apply said final electrical command signal as said electrical pressure command signal (207) to said pressure generating means (205);

Characterized in that:

(A) the apparatus includes governing means configured to provide that, in use of the apparatus , said final command signal is a signal, representative of a value of Pvent, determined by said gain factors and generated in accordance with the equation:

Pvent = (A/(1+A))ErsV + (A/(1+A))Rrsv,

wherein:

A is the proportionality constant between Pvent and Pmus in the equation: Pvent = PmusA, A/(1+A))Ers and A/(1+A)Rrs are the values of the gain factors, Ers is the elastance of the patient and Rrs is the respiratory resistance of the patient,

(B) the apparatus includes means for storing data representative of the elastance of the patient;

(C) that the apparatus includes means for storing data representative of the resistance of the patient.

VIII. The appellant argued as follows.

(a) Regarding the question whether document D1 belongs to the state of the art the appellant essentially submitted the following:

The communication of North Dakota state University was unsatisfactory. The statement that the document was placed on the library shelves on May 1985 appeared to be a slavish repetition of what the front page of the document said. No reference was made to any internal catalogue or any other reference. Usually library records were as demonstrated by those which featured in decision T 381/87 (precise date of publication supported by library record extract). One would expect a specific date to be mentioned and not simply the month concerned. Furthermore it was not sure whether the date on the front page of D1 was the completion date of the thesis, its release date, or the starting date of the research or other work. The typed date could have been a misprint or even a falsehood. A typed date had none of the hallmarks of authenticity of a printed document and it should have been corroborated by external evidence. According to decision T 750/94 the evidence concerning alleged prior publications must be critically and strictly examined and a European patent should not be refused or revoked unless the grounds for refusal were fully and properly proved. The statement of North Dakota State University added nothing to the document which was under suspicion. The inventor, after the filing of Article 115 EPC observations, was unable to obtain a copy of document D1 other than by way of personal visit. In 1991 he was refused his request to Dr Poon for a copy. Guidelines C-IV 5.2 (60) state that "if the applicant shows sound reasons for doubting whether the document forms part of the "state of the art" in relation to his application and any further investigation does not produce evidence sufficient to remove that doubt the examiner should not pursue the matter further".

(b) Regarding Article 52(4) EPC, the invention did not claim a method of ventilation as such.

(c) Regarding novelty and inventive step in relation with document D1, said document did not disclose the proportionality factors K1 and K2. Pressure, flow and volume in document D1 were all controlled (see page 128 and Table 6.1). This was possible only in paralysed and apneic patients. When the patient was making an effort, one could either control flow and volume or pressure, but not both. See also page 15, line 9; page 28, item 2; page 38, last sentence; page 39, item 1; page 80, lines 8, 9; page 81, last sentence; page 82, last sentence; page 94, first sentence; page 128, last sentence; page 129, last sentence; page 130, Table 6.1.

Referring in particular to the third auxiliary request, the special notation: A/(1+A) which for every A gives a result less than one, made it explicit that the gain factor K was always a fraction of the elastance/resistance in order to prevent runaway. The coefficient A was input manually by the operator. Document D1 did not disclose such restriction.