acute hemodialysis prescription
Post on 16-Oct-2015
Embed Size (px)
25/1/2014 Acute hemodialysis prescription
Official reprint from UpToDate www.uptodate.com 2014 UpToDate
AuthorsPhillip Ramos, MD, MSCIMark R Marshall, MDThomas A Golper, MD
Section EditorsJeffrey S Berns, MDPaul M Palevsky, MDRichard H Sterns, MD
Deputy EditorAlice M Sheridan, MD
Acute hemodialysis prescription
All topics are updated as new evidence becomes available and our peer review process is complete.Literature review current through: Dec 2013. | This topic last updated: ene 9, 2013.
INTRODUCTION Acute renal failure (ARF) is a major cause of morbidity and mortality, particularly in the
hospital setting. Despite improvements in renal replacement therapy (RRT) techniques during the last several
decades, the mortality rate associated with ARF in critically ill patients remains above 50 percent. (See "Renal
and patient outcomes after acute tubular necrosis".)
RRT is ideally initiated in the acute setting prior to the dangerous accumulation of extravascular volume and/or
uremic toxins that can result in further multi-organ damage and failure. Once the decision to initiate RRT has
been made, the specific modality of dialytic support must be chosen. This consists of peritoneal dialysis,
intermittent hemodialysis (IHD) and its variations (eg, hemofiltration), and continuous RRT (CRRT). Once the
selection is made, the acute dialysis prescription can be determined.
An acute hemodialysis treatment is defined as a hemodialysis session specifically performed for ARF (also
known as acute kidney injury [AKI]) or in the setting of a hospitalized end-stage renal disease (ESRD) patient.
The choice of specific dialysis modality, particularly the choice between continuous or intermittent dialysis, is
discussed separately. (See "Continuous renal replacement therapy in acute kidney injury (acute renal failure)".)
The various components of the acute hemodialysis prescription will be described here. The use of peritoneal
dialysis in ARF is discussed separately (see "Use of peritoneal dialysis for the treatment of acute kidney injury
(acute renal failure)").
INDICATIONS The urgent indications for renal replacement therapy (RRT) in patients with acute renal failure
(ARF) generally include volume overload refractory to diuretics, hyperkalemia, metabolic acidosis, uremia, and
toxic overdose of a dialyzable drug. In an attempt to minimize morbidity, dialysis should be started prior to the
onset of overt complications of renal failure, whenever possible. This is discussed in detail separately. (See
"Renal replacement therapy (dialysis) in acute kidney injury (acute renal failure) in adults: Indications, timing,
and dialysis dose", section on 'Indications for and timing of initiation of dialysis'.)
MODALITY Once the decision to initiate renal replacement therapy (RRT) has been made, the specific
modality of dialytic support must be chosen. The possibilities include peritoneal dialysis, intermittent
hemodialysis (IHD) and its variations (eg, hemofiltration), and continuous RRT (CRRT). Once this selection is
made, the acute dialysis prescription can be determined. The determining factors of which modality is chosen
include the catabolic state, hemodynamic stability, and whether the primary goal is solute removal (eg, uremia,
hyperkalemia), fluid removal, or both. This is reviewed elsewhere. (See "Renal replacement therapy (dialysis) in
acute kidney injury (acute renal failure) in adults: Indications, timing, and dialysis dose".)
VASCULAR ACCESS When acute hemodialysis is chosen as the dialytic support modality, vascular access
must be established prior to initiating treatment. Placement of the venous dialysis catheter must be considered
carefully, especially in the critically ill patient.
The location depends upon factors such as body habitus, whether the patient is ambulatory or bedridden,
presence of vascular disease or atypical anatomy, and the avoidance of specific complications in an at-risk
25/1/2014 Acute hemodialysis prescription
patient (eg, risk of pneumothorax while placing a subclavian venous dialysis catheter in a patient with severe
chronic obstructive pulmonary disease or history of deep vein thrombosis or other venous disease).
For hospitalized end-stage renal disease (ESRD) patients, daily reassessment of the existing angioaccess (eg,
arteriovenous graft or fistula) is appropriate. Many events during the hospitalization can jeopardize the existing
access (eg, hypotension). (See "Overview of central catheters for acute and chronic hemodialysis access".)
HEMODIALYZER MEMBRANES In the setting of acute renal failure (ARF), the choice of artificial membranes
utilized may have a bearing on clinical outcome. Previously, it was postulated that non-complement-activating
membranes may incur less inflammatory risk, with resultant decrease in infectious complications and possibly
an increased probability of improved restoration of renal function. However, there are inconsistent findings
concerning the effect of membrane biocompatibility on outcomes among patients with ARF, with several meta-
analyses reporting disparate results. (See "Renal replacement therapy (dialysis) in acute kidney injury (acute
renal failure): Recovery of renal function and effect of hemodialysis membrane", section on 'Complement
activation, membrane biocompatibility, renal recovery, and survival'.)
Membranes can also be of low or high flux. High-flux membranes contain large pores that allow for enhanced
permeability of larger molecules . Although this property can enhance removal of putative toxins and improve
outcome, it could also allow the back transport (from dialysate to blood) of potentially harmful water-borne
molecules. This property is a factor that confounds some of the conclusions from previously performed studies.
Certainly, having the purest dialysate water possible should be a goal when using these more porous
membranes to utilize their positive attributes and to minimize their potential risks.
Overall, there are theoretical advantages to high-flux biocompatible membranes that have not been consistently
corroborated by often underpowered or flawed clinical studies. However, the effect of membrane biocompatibility
on outcomes (when present) is consistently beneficial. In addition, since such membranes can now be obtained
cheaply, cost has been eliminated as a deciding factor.
We therefore suggest the following approach:
(See "Renal replacement therapy (dialysis) in acute kidney injury (acute renal failure): Recovery of renal function
and effect of hemodialysis membrane", section on 'Complement activation, membrane biocompatibility, renal
recovery, and survival' and "Renal replacement therapy (dialysis) in acute kidney injury (acute renal failure):
Recovery of renal function and effect of hemodialysis membrane", section on 'Membranes' and "Maintaining
water quality for hemodialysis".)
DIALYSATE COMPOSITION The dialysate solution composition consists of potassium, sodium, bicarbonate
buffer, calcium, magnesium, chloride, and glucose. Unlike chronic hemodialysis, the dialysate composition in
acute hemodialysis is routinely altered each treatment to correct the metabolic abnormalities that can rapidly
develop during acute renal failure (ARF). This is particularly true in the treatment of potassium and/or acid/base
derangements. Thus, the dialysate potassium, sodium, bicarbonate, and calcium are routinely changed in this
Issues surrounding magnesium, chloride, and glucose include the following:
If the water system used is high quality, high-flux biocompatible dialysis membranes should be used in the
If the water system is not of high quality, low-flux biocompatible dialysis membranes should be used.
Another option is the use of in-line membrane filtration devices on dialysis machines to generate ultrapure
The usual dialysate magnesium concentration is 0.5 to 1.0 mEq/L and is not usually different from that in
the chronic setting.
The amount of dialysate chloride is dependent upon the dialysate sodium and bicarbonate concentrations.
The standard dialysate glucose concentration is 200 mg/dL, but may be decreased to more efficiently
lower the serum potassium during hemodialysis.
25/1/2014 Acute hemodialysis prescription
Dialysate potassium concentration There is no standard dialysate potassium concentration in the acute
hemodialysis prescription because of wide variability in serum potassium prior to initiating the hemodialysis
session. It is crucial to know the predialysis serum potassium level at the start of the hemodialysis session to
tailor the dialysate potassium so that normokalemia will be attained with avoidance of hypokalemia.
The goal of an acute hemodialysis treatment is not necessarily to lower the total body potassium burden for
general nutritional purposes. Instead, the goals are often more short term, such as normalizing the s