Patents - Tehrani v Hamilton Bonaduz AG and others
Intellectual Property Enterprise Court (HH Judge Hacon) Tehrani v Hamilton Bonaduz AG and others  EWHC 3457 (IPEC) (22 Dec 2021)
This was an action for patent infringement and a counterclaim for revocation. The patent in suit was GB2423721B and not GB2424721 as stated in the transcript. The invention for which the patent was granted was a “Method and apparatus for controlling a ventilator”. The patentee, Professor Tehrani, complained that the marketing of Hamilton Medical's Invellivent-ASV system infringed her patent. The suppliers of that system, Hamilton Bondauz AG and others, challenged the validity of the patent on grounds of anticipation, obviousness and insufficiency. The action and counterclaim came on for trial before Judge Hacon on 6 and 7 July 2021. By para  of his judgment in Tehrani v Hamilton Bonaduz AG and others  EWHC 3457 which was delivered on 22 Dec 2021, the judge held that the patent was invalid for want of novelty and an inventive step but had it been valid claim 1 but not claim 45 would have been infringed.
The abstract is as follows:
"Method and apparatus for controlling a ventilator are described. The invention can be used to control mechanical ventilators (56) as well as respiratory assist devices such as CPAP machines. The apparatus receives input data indicative of patient's oxygen level. A controller (10) determines PEEP, or CPAP, and FIO2, on the basis of data indicative of the patient's oxygen level. In an alternative embodiment, the apparatus further receives input data indicative of patient's carbon dioxide levels, respiratory elastance and airway resistance, and barometric pressure. The controller further utilizes the said input data to determine the optimal values of tidal volume and breathing frequency for a next breath of the patient, and uses the respiratory elastance and airway resistance data to determine any necessary adjustments in the I:E ratio. The controller also applies safety rules, detects and corrects artifacts, and generates warning signals when needed."
The judge set out the technical background to the invention between para  and para  of his judgment. He summarized the teaching between  and .
Two claims were in dispute, namely claim 1 and claim 45. His Honour broke them down into integers at paras  and :
“1A An apparatus for automatically controlling a ventilator comprising:
1B first means for processing data indicative of at least a measured oxygen level of a patient, and for providing output data indicative of:
1C required concentration of oxygen in inspiratory gas of the patient (FiO2) and positive end-expiratory pressure (PEEP) for a next breath of the patient;
1D wherein FiO2 is determined to reduce the difference between the measured oxygen level of the patient and a desired value;
1E wherein PEEP is determined to keep a ratio of PEEP/FiO2 within a prescribed range and, while keeping the ratio within the prescribed range, to keep the measured oxygen level of the patient above a predefined value; and
1F second means, operatively coupled to the first means, for providing control signals, based on the output data provided by the first means, to the ventilator;
1G wherein the control signals provided to the ventilator automatically control PEEP, and FiO2, for a next breath of the patient.”
At para , Judge Hacon said:
'45A An apparatus for automatically controlling a ventilator comprising:
45B (a) means for providing data indicative of the measured oxygen level of the patient;
45C (b) means for providing data indicative of the measured carbon dioxide level of the patient;
45D (c) means for providing data indicative of respiratory elastance, and respiratory airway resistance of the patient;
45E (d) a programmable controller storing executable instructions that when executed perform the steps of:
45F (I) determining, from the data indicative of the measured oxygen level of the patient provided by (a), a required concentration of oxygen in an inspiratory gas of the patient, FiO2, to reduce a difference between the measured oxygen level of the patient and a desired value, and providing a data signal indicative of the required FiO2;
45G (II) determining a required positive end-expiratory pressure, PEEP, and providing a data signal indicative of the required PEEP, wherein the required PEEP maintains a ratio of PEEP/ FiO2 within a prescribed range, and while the ratio is maintained within the prescribed range, to keep the measured oxygen level of the patient above a predefined value;
45H (III) determining, based upon the data provided by (a), (b), and (c), an optimal breathing frequency, a required ventilation, and a required adjustment in inspiration to expiration time ratio, I:E, for a next breath of the patient, and providing data signals indicative of the same; and,
45I (e) means for providing to the ventilator, based upon the data signals provided by (I), (II) and (III), final data signals for automatically controlling: (i) the required FiO2, the required PEEP, (iii) the optimal breathing frequency, (iv) the required ventilation, (v) the required adjustment in I:E ratio, for a next breath of the patient.'”
(1) Anderson J.R. and East T.D, A closed-loop controller for mechanical ventilation of patients with ARDS, Biomedical Sciences Instrumentation 2002, vol. 38m 289-294 (“Anderson”);
(2) Waisel et al., PEFIOS: An Expert Closed-Loop Oxygenation Algorithm, Medinfo ’95: Proceedings of the Eighth World Congress on Medical Informatics, Vancouver Trade & Convention Centre, Vancouver, British Columbia, 23-27 July 1995 (“Waisel”);
(3) US Patent No. 4 986 268 (“US 268”); and
(4) Tehrani F, Dual Control System for Ventilatory Treatment of Premature Infants, Proceedings of the 5th International Conference on Information Systems, Analytics and Synthesis, Vol. 8, Concepts and Applications of Systemics, Cybernetics and Informatics, 31 July - 4 August 1999 (“the Tehrani Paper”).
The arguments on insufficiency were run on squeezes and did not arise.