DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election without traverse of Group I (claims 1-16) in the reply filed on July 30, 2026, is acknowledged. Therefore, claim 17 is withdrawn.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-16 are rejected under 35 U.S.C. 101 because the claimed invention lacks patentable utility.
Claim 1 and claim 16 each recites a method for determination of net fluid removal from a patient during continuous kidney replacement therapy (CKRT), and includes these steps: calculating a predicted body weight, selecting a strategy, based on those two factors, determining a net fluid removal rate, calculating a total rate of IV fluids added, adding that total rate to the new fluid removal rate to determine the final net fluid removal rate. These steps are more akin to data entry and intended use rather than a method of operating the device with the determined final rate. Combining the rate of added IV fluid to the rate of fluid removed for determining the final net fluid removed is ineligible subject matter because it is a mathematical concept. See MPEP 2106.04(a).
The Court’s rationale for identifying these "mathematical concepts" as judicial exceptions is that a ‘‘mathematical formula as such is not accorded the protection of our patent laws,’’ Diehr, 450 U.S. at 191, 209 USPQ at 15 (citing Benson, 409 U.S. 63, 175 USPQ 673), and thus ‘‘the discovery of [a mathematical formula] cannot support a patent unless there is some other inventive concept in its application.’’ Flook, 437 U.S. at 594, 198 USPQ at 199. The last limitation of claim 1 or claim 16 recites setting the determined final net fluid removal rate on a CKRT machine. It is insufficient as the inventive concept that can support a patent, because this step is simply inputting the result of the abstract process onto the machine, akin to jotting down the answer after doing a series of calculations. Subsequently, the step of setting the determined final net fluid removal rate on a CKRT machine is considered to be an insignificant extra-solution activity that fails to integrate the mathematical calculations into a practical application.
Claims 2-13 further define a variable used in the calculation but do not add a step that changes the operation of the CKRT machine or dialysis process.
Claims 14-15 further clarify the calculation of the net fluid removal rate but are not performing actual steps of operating the CKRT or carrying out dialysis.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 4-13 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 4 recites the limitation "a restrictive strategy." It is unclear if that refers to the restrictive strategy in claim 1 or a new restrictive strategy. Claims 5-7 are also rejected as being indefinite due to their dependency on claim 4.
Claim 9 recites the limitation "a liberal strategy." It is unclear if that refers to the liberal strategy in claim 1 or a new liberal strategy. Claims 10-13 are also rejected as being indefinite due to their dependency on claim 9.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Golarits et al. (US 20160121037 A1) discloses a renal replacement therapy that controls a target net fluid removal rate. The substitution fluid, dialysis fluid, and the citrate flow rates are monitored with the effluent rate to keep the net fluid removal rate within a limited range to not cause a large weight loss rate for the patient. Golarits considers the weight of the patient and maintains a safe net removal rate but does not expressly calculate the net rate by adding a rate of infused IV fluids to a net fluid removal rate (based on the predicted weight and a restrictive or liberal strategy) to determine a final net fluid removal rate.
Burbank et al. (US 20170296727 A1) discloses a fluid balancing system wherein the rates of ingoing and outgoing pumps are regulated to maintain safe net inflow and outflow rates. Although Burbank teaches the importance of fluid balancing in an extracorporeal circuit, Burbank separately controls various pumps to maintain the net rates separately and is not determining one final net rate to set on the controller. Furthermore, it is unclear how Burbank is determining its initial rate of fluid removal but it is not explicitly based on a predicted weight of the patient nor a liberal or restrictive strategy.
Lemer et al. (US 20240181146 A1) discloses a continuous renal replacement therapy system wherein the ultrafiltration rate to adjusted to maintain a safe net fluid removal rate. Lemer is directed more towards a retroactive adjustment of the ultrafiltration rate after the device has begun filtration rather than determining what a target net fluid removal rate should be and then setting that rate with the controller to maintain.
Golarits, Burbank, and Lemer all similarly disclose the importance of maintaining a safe net fluid removal and how that rate varies based on each patient’s specific needs, but none of these references cite the calculation of a final net fluid removal rate by adding the total rate of infused fluids to the rate of removal.
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/ERIN A KIM/Examiner, Art Unit 3781
/SUSAN S SU/Primary Examiner, Art Unit 3781 1 October 2026
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