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'The modified filter strategy removes two (2) to three (3) percent more potassium than in standard dialysis. Further tests are needed to determine whether this small increment justifies the added cost.'

- Mukherjee JJ, International J Dialysis (2011)

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HOST: Today on Science Saturday we are pleased to have an internationally known expert on kidney dialysis, Dr JJ Mukherjee of the X Institute of Renal Failure. The good doctor works right here at the university hospital, just blocks from our studio.

Dr Mukherjee will describe a groundbreaking discovery that has profound implications for the unfortunate victims of kidney disease whose lives depend on dialysis, that critical therapy of last resort. When the kidney is no longer up to snuff, the dialysis machine steps up in to restore the precarious balance of sodium, potassium and water that makes life, as we know it, possible.

Welcome to our show, Dr Mukherjee.

Dr JJM: Thank you for the unexpected invitation. I've never been on the radio before.

HOST: We will do our best, then, to draw you out. Reshaping your expertise into nuggets that are readily digested by the general public: that’s my job.

Dr JJM: Sounds good.

HOST: How about we spend this hour unlocking the mysteries of potassium for our listeners.

Dr JJM: Okay.

HOST: Describe for us, doctor, the chemical imbalance that results from kidney failure. There is a chemical imbalance, isn't there, when the beans don't work?

Dr JJM: You can say that, yes. The kidney is responsible for filtering out impurities, such as creatinine and urea, that otherwise build up as by-products of digestion. The kidney also eliminates excess potassium, most of which we get from the food we consume, such as bananas and oranges.

HOST: So the very things that sustain us, the fruits of our labor --- well, not our labor exactly but that of the farmer --- these fruits that fuel our great efforts even if those efforts are focused on who is going to win the next Dancing with the Stars, these very same fruits can be the downfall of the kidney patient? Is this what you're saying, Doctor Mukherjee? I mean, kidney patients have to eat too, after all.

Dr JJM: Of course they do. But we make sure that the patient avoids those foods that are high in potassium.

HOST: As if it weren't bad enough that the plumbing's busted, the water treatment plant is kaput, you might say. But then we have to worry about someone pouring banana smoothies down the proverbial drain.

Dr JJM: It's not that difficult to avoid potassium in the diet.

HOST: You can't win for losing sometimes, isn't that right, doctor? A guy likes his bananas and orange juice, and just like that he's stuck on dialysis.

Dr JJM: Um, only if his ...

HOST: Is there anything else besides dialysis for this guy? I mean, one day the poor sucker is out playing ball, maybe football or baseball or whatever-ball, and the next day he's dragging a ball-and-chain.

Dr JJM: The patient must go to the machine. He can't take it with him. That's not an option.

HOST: Seems like a mighty stiff sentence for sneaking some orange juice. Can't we find another way to combat the scourge of high potassium?

Dr JJM: If the patient has some remaining kidney function, we use diuretic medications to modify the urine.

HOST: So you're saying that you fight hyper-potassium on three or more fronts, with dialysis being your big gun, your cannon at the Battle of Water-in-the-loo. But let's back up for a minute. Could you describe for our listeners the effects of out-of-control potassium? What exactly does potassium sabotage when it is allowed to run amok?

Dr JJM: Well, potassium is an integral component of cell-to-cell communication. Sodium, potassium and calcium are charged ions with conductivity properties requisite for sino-atrial and A-V nodal function.

HOST: I'm afraid you've gone over my head there, doctor.

Dr JJM: Too much potassium can result in abnormal electrical conduction, especially in the heart.

HOST: OOOoooooh. Let me rephrase that for our audience, if I may, doctor: kidney failure can lead to high potassium levels that overwhelm the vital electrical circuitry of the body. Picture this nightmarish scenario: the potassium ions rise up as powerful cardiac electrons, no, protons. Protons, actually. Protons galloping at full speed through the so-called conducting system without any regulation whatsoever, without a resistor in sight --- there’s nothing in their way --- wreaking havoc where there once was the calm lub-dub, lub-dub of the steadily beating heart!

Dr JJM: There is just a small risk of conduction abnormalities. Most patients experience no arrhythmias at all.

HOST: An abnormal rhythm could upset the whole applecart, hey doctor? We wouldn’t want that to happen.

Dr JJM: The risk is tiny, really.

HOST: It’s as if the circuits are overloaded and the fuse is ready to blow. Just what is the fuse in this system? It’s the kidney, isn’t it! No, the kidney would be a sink, a sump. The kidney is a diversion. Help me here, doctor. What would be the proper analogy for our listeners?

Dr JJM: I’m not sure.

HOST: It's a circuit breaker, yes?

Dr JJM: Um ...

HOST: It’s a pop-off valve! That’s it. The kidney is a pop-off valve. A critical mass of potassium boils to the surface, threatening the electrical security of the entire cardiac rhythm system, then Bam! The ever-vigilant kidney siphons off the potassium-rich slurry just in the nick of time. Wow. Threat minimized. The kidney is an amazing organ, wouldn’t you say, doctor?

Dr JJM: It performs some impor ...

HOST: What does it feel like, all this extra potassium cascading through the veins? I imagine it flows even faster through the arteries. Is it like the meager power of two double-A batteries? A fat D-cell perhaps? Or is it like one of those 6-volt gargantuan block batteries that you put in camping flashlights? Maybe, doctor, it's like if you stuck your tongue on a 9-volt! I mean, we've all done that.

Dr JJM: I don't think the patient actually feels anything, most of the time. Unless of course if their feet are swollen. I suppose that might be uncomfortable.

HOST: So it is bad enough the kidneys aren't working. Now hanging over the head of the dialysis patient, like a sword of Damocles, is the constant threat of potentially fatal cardiac rhythms. So into the story comes your breathtaking discovery: how to remove the specter of abnormal heart rhythms, the bane of any kidney patient's existence, along with swollen limbs and ... and ...

Dr JJM: ... the blood pressure?

HOST: The blood pressure! It must be high. Or maybe it's low? I understand that kidney patients are often anemic.

Dr JJM: It's high. The blood pressure is too high. It's never low.

HOST: So it's as if the anemic bloodstream has fewer deliverymen trying to carry vitally needed oxygen to its final destination, and these valiant warriors have to fight upstream against inexorably high blood pressure. Is that it, doctor?

Dr JJM: It's high resistance that's the problem, blood pressure is an indirect measure of . . .

HOST: But tell us now how, in order to wrestle the potassium under control, you modified the dialysis filter.

Dr JJM: We didn't actually modify the filter. All we did was, we ran the dialysis fluids two to three percent faster than is the usual practice.

HOST: So you sped up the machine?

Dr JJM: A little bit.

HOST: If I may, for our listeners: in dialing up the flows by a critical amount, these researchers have opened the proverbial floodgates. A slurry rich in potassium now whizzes through the pipes at breathtaking speed, heading for the exit. You have turbo-charged the system, as it were. The result is less potassium in the bloodstream, less cardiac abnormal rhythms.

Dr JJM: Fewer. Fewer abnormal cardiac rhythms. Maybe. We didn't actually monitor that.

HOST: And this extraordinary breakthrough must mean that your patients once again experience the joys of an unrestricted diet.

Dr JJM: It is too early to say. There were just three patients . . .

HOST: No more limits for the now-fortunate dialysis recipient, I suppose?

Dr JJM: I wouldn't say that.

HOST: . . . more orange juice perhaps? More bananas?

Dr JJM: Half a banana. At most.

HOST: It sure seems to me that you have cracked the code on this one. With its publication in an internationally renowned journal of dialysis, the Mukherjee Method should be well on its way to becoming the new standard of care.

Dr JJM: I was just relieved to have this case report published. When I finish my residency I might devote more time to this problem. I might even go into nephrology.