DaVita® Medical Insights

Dialysis Patient FAQs

Although the physician writes the dialysis orders, the patient care technicians (PCTs) and nurses have the most interaction with the patient. As the relationship between the patient and the care team develops and as the patient experience with dialysis increases, many questions arise regarding dialysis care. Some commonly asked questions and my responses to them follow. Note: Below are general responses not to be used verbatim, as they may not be appropriate answers for all patients; please adjust your communication to the individual patient.

1. Can I shorten my time?

Patients spend, on average, three half days per week at the dialysis facility and they value their time. To answer this question and clear up some misconceptions, it is important to discuss the three functions of a dialysis treatment. First, dialysis removes metabolic waste from the blood. Second, it removes fluid from the circulating blood volume. Third, it corrects the body chemistry. Typically, the dialysis adequacy (Kt/V) values measure quite well the removal of waste after a single treatment, and the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend a minimum Kt/V of 1.2, with a DaVita goal of 1.4. If the Kt/V is below the goal range, the most common remedy is to increase time on dialysis, although additional factors may need to be considered (such as dialyzer size).

The second important consideration is the amount of fluid that must be removed during a treatment. The patient weigh-in allows an assessment of the fluid gain in the body since the last dialysis treatment. The rate at which fluid is removed from the body is a patient safety issue, as rapid fluid removal may result in a precipitous fall in blood pressure and cardiovascular instability. Patients who present with significant edema first undergo removal of fluid from the circulation, with subsequent shifting of fluid from the tissues into the blood. Rapid depletion of intravascular volume may lead to cardiac “stunning” and possible related complications. Thus, the amount of fluid removal per minute must be limited, and patients may need to extend their time on dialysis in order to remove excess volume safely.

Finally, the dialysis treatment corrects body chemistry, most importantly, metabolic acid and potassium. As the dialysis machine removes potassium and acid from the blood, a significant shift occurs out of cells—which have nearly a 35 times higher potassium concentration than the plasma. The correction of total body potassium may be a lengthy process. The treatment must be long enough to provide adequate clearance of acid and potassium, among other chemicals.

2. Why can’t I keep my catheter?

The obvious advantage of a catheter is the ability to avoid needles. However, patients with long-standing catheters routinely have injury to the central veins with subsequent stenosis, leading to catheter dysfunction, extremity swelling and pain. Catheters are also associated with a higher incidence of infection, which may spread to other parts of the body, and the mortality of patients who dialyze with a catheter is substantially higher than for those who have a permanent access. Catheters may result in worse anemia due to decreased response to hematopoietic drugs. In summary, catheters may be best avoided, because they carry markedly increased risk compared with other forms of dialysis access, such as fistulas.

3. If I drink fluid while on dialysis, can’t you just remove it?

Many patients will arrive with a large beverage that they plan to drink while on dialysis, because “you can just take the fluid off.” Often, these patients will have a large fluid gain since their last treatment, and the additional fluid from the drink will likely prevent them from meeting their goal weight. Also, the demand for increased fluid removal will increase the likelihood of low blood pressure and increased risk of a complication during treatment.

4. Why are you recommending an extra treatment?

Again, this relates to the ability to remove excess fluid safely. Current recommendations are to limit fluid removal to no more than 13 mL per kg per hour. In other words, for a 60-kg (132-pound) person, no more than 780 mL of fluid should be removed per hour. If the treatment length is four hours, the maximum recommended fluid removal is 3.1 L. If a patient arrives at dialysis 4 kg over base weight, and this happens repeatedly, arriving at the goal weight will likely be very difficult to achieve without extra treatments.

5. I have noticed that I hardly produce any urine any more. Isn’t that bad?

For most patients, dialysis begins while there is still some residual kidney function. The process that caused the kidneys to fail will continue to progress, and most patients will stop making urine altogether after some time on dialysis. As the urine output eventually falls to zero, the patient will need to be even more careful about fluid intake to avoid volume overload.

6. I never miss dialysis, I stay for the full treatment every time, yet my phosphorous stays high. What am I doing wrong?

Control of phosphorous is complex and one of the most difficult aspects of having renal failure. The balance of phosphorous in the body is related to the ability of the kidneys to excrete excess phosphorous, to dietary intake, to the overall acid-base balance and to the state of metabolism of the bones, which is altered dramatically in kidney failure. Dialysis is relatively ineffective at normalizing the body’s phosphorous level, since most phosphorous is not contained in the plasma but is instead in cells and bone. Controlling the phosphorous level takes active effort on the part of the patient and care team to include limiting the ingestion of phosphorous-rich foods, taking binders to reduce absorption of dietary phosphorous and controlling the body’s metabolism of bone.

7. Why do I feel so weak after dialysis?

Most of the time, the degree to which patients feel symptomatically weak after dialysis is related to the volume of fluid that was removed. Patients who are cautious about fluid intake and arrive at dialysis with minimal fluid gains often tolerate dialysis much better than those who need large volumes of fluid removed. The greatest body compartment for fluid is the circulation, and once a large amount of fluid is removed from the bloodstream, fluid will shift from other areas, such as muscle and other soft tissues. The degree and rate to which this occurs usually dictate the severity of symptoms.

8. Why is it so important to avoid salt?

By limiting salt intake, you will reduce thirst and control the desire to ingest excessive fluid. The brain controls the concentration of sodium in the blood and keeps it within a very narrow range. When you ingest salt, it raises the blood sodium level, and the brain’s response is to stimulate thirst.

9. Should I take my blood pressure medication before treatment or hold it?

The individual patient’s blood pressure during treatment should be considered to answer this question. For patients who tend to experience a significant fall in blood pressure during treatment, holding antihypertensives prior to treatment may help to avoid episodes of hypotension. Patients who experience persistent high blood pressure despite fluid removal during dialysis should continue to take their medication per their usual schedule. Patients should always be instructed to ask their physician about any medication concerns.

10. How do I get on the transplant list?

The process of “getting on the list” usually involves evaluation by a transplant center, where the associated testing is performed and the patient’s eligibility for transplantation is determined. Most referrals to the transplant center are made by the patient’s nephrologist, although patients will often contact the transplant center themselves and “self-refer”. The dialysis facility social worker may also provide the patient with information about transplantation resources.

David L. Mahoney, MD

David L. Mahoney, MD

David L. Mahoney, MD, is chief medical officer of Lifeline Vascular Care. Before joining Lifeline he was in private practice for more than 20 years in the Washington, DC, area, where he was also the medical director of a DaVita Kidney Care chronic dialysis facility, a hospital acute dialysis service and his practice's vascular access center. From 2013 to 2017 he served as a group medical director for DaVita Kidney Care. Dr. Mahoney received his undergraduate degree in biochemical sciences from Harvard College and his medical degree from Boston University School of Medicine. He completed residency and fellowship training at Walter Reed Army Medical Center in Washington, DC. He served for 10 years on active duty as an Army physician before entering private practice in 1995. Dr. Mahoney and his wife live in Washington, DC and have three adult children.