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What is sodium modeling in hemodialysis patients?
What is sodium modeling in hemodialysis patients?
Causes of Intradialytic hypotension(IDH)
Intradialytic Hypotension
Reduced ECVImpaired Vaso-
constriction
Heart problems
Myocardial Infarction
Structural heart dis.
Arrythmias
Pericardial tamponadeDialyzer Rxn Air embolism
Hemolysis
Hemorrhage
Reduced plasma refill-
ing rate
Excessive fluid removal
Ultrafiltration rate > 0.35 ml/min/kg
Decrease in plasma vol. > 20%
Patient-related factors
Autonomic neuropathy (e.g. DM, Uremia)Antihypertensive medications
Sympathetic failure ( 적절한 plasma NE↑ 가 無 )RAS and arginine-vasopressin syst. sensitivity↓
Food ingestion(splanchnic vasodilation)Tissue ischemia(adenosine mediated)
Bacterial sepsisIntradialytic venous pooling
Core body temp↑.Anemia.
Dialysis-related factors
Acetate dalysate (adenosine-mediated)Low dialysate Na &/or ionized Ca conc.
Complemant activation (C3a and C5a-mediated)Cytokine generation(IL-1 and NO-mediated)
Water movement during standard hemodialysis
Water movement
Intracellular fluid Extracellular fluid Dialyzer
Osmolality320 mosm/kg
Osmolality320 mosm/kg
Loss of urea and water
step1
step2
step3
280
Osmolality320 mosm/kg
Falling to 290mosm/kg
as diffusion occurs
Compensatory refilling
Fluid removal
Plasma refilling
Low Na 130-135 meq/l
Na
Fluid removal Fluid removal
Na
Increased risk of hypotension
Historically the dialysate Na was maintained at hyponatremic level, 130-135:
Historically the dialysate Na wasmaintained at hyponatremic level, 130-135:
To prevent: Intradialytic hypertension Thirsty Interdialytic weight gain
To prevent: Intradialytic hypertension Thirsty Interdialytic weight gain
Disadvantages of dialysates with low sodium concentration:
Disadvantages of dialysates with lowsodium concentration:
Increased risk of hypotension Increased risk of intradialytic cramps Increased risk of dialysis disequilibrium
syndrome
Increased risk of hypotension Increased risk of intradialytic cramps Increased risk of dialysis disequilibrium
syndrome
urea removed by dialyzer
Effluent Dialysate
Inffluent Dialysate
urea sequestration in tissue
Increased intracellular osmolarity
fluid
Na
fluid
High dialysate sodium:High dialysate sodium:
Advantages:
Decreased risk of hypotension
Decreased risk of intradialytic cramps
Decreased risk of dialysis disequilibrium syndrome
Advantages:
Decreased risk of hypotension
Decreased risk of intradialytic cramps
Decreased risk of dialysis disequilibrium syndrome
Disadvantages:
Increased rate of hypertension
Interdialytic weight gain
Polydipsia
Disadvantages:
Increased rate of hypertension
Interdialytic weight gain
Polydipsia
Low Na >145 meq/l
Na
Fluid removal Plasma refilling
Na
Different patterns of sodium modeling Different patterns of sodium modeling
Na concentration
Hours after dialysis initiation
145-155 meq/lit
135-140 meq/lit
Dialysate Na should be regulated based on serum Na:
Dialysate Na should be regulated based onserum Na:
hyponatremia:
If Na > 130: Dialysate Na: 140-(140-predialysis Na)
If Na<130: Dialysate Na: Predialysis Na + 15-20
Hypernatremia:
Dialysate Na: Predialysis Na-2 mmol
hyponatremia:
If Na > 130: Dialysate Na: 140-(140-predialysis Na)
If Na<130: Dialysate Na: Predialysis Na + 15-20
Hypernatremia:
Dialysate Na: Predialysis Na-2 mmol
Goals of UF Profiling Provide adequate ultrafiltration (UF)
Minimize symptoms related to hypovolemia
Enhance plasma refill
Allow the patient to reach estimated dry weight (EDW)
Hypovolemia: Decreased blood volume leads to decreased cardiac output which can cause hypotension
Plasma refill: Refilling of the blood compartment, or vascular space from the surrounding tissue spaces
20
Fluid Spaces in the Body
BONE, MUSCLE, FAT
VASCULAR SPACE4 LITERS WATER, 5%
INTERSTITIAL SPACE11 LITERS WATER, 15%
INTRACELLULARSPACE
27 LITERS WATER
40%
60% of Total Body Weight
is 42 liters
ofwater
70 kg or 154 lbs.
Extr
acellu
lar
Average weight Male
21
The loss of circulating volume in the vascular space The loss of osmolarity as the urea is removed during
dialysis
Only fluid in the vascular space is available during dialysis for ultrafiltration. This amounts to less than 4L in the average patient
Two Basic Reasons That Patients End up With Dialysis Symptoms During Treatment
22
Symptom EtiologyWith Constant Ultrafiltration
Ultrafiltration (UF) removes water volume from the blood into the dialysate, causing hypovolemia
Symptoms of Volume loss:• Hypotension
• Cramping
• Dizziness
• Nausea
• Vomiting
• Shock
23
Profiling Ultrafiltration: Allows the patient to reach their estimated dry weight (EDW)
Helps prevent symptoms
Allows refilling of vascular fluid volume from the interstitial space (plasma refill)
Allows higher volume fluid removal at times when fluid is more readily available
Prevents hypotension
24
How to Do UF Profiling
Identify patients with dialysis related symptoms
Analyze patient’s treatment records
Decide if the patient will benefit from a profile
Choose a profile that matches your analysis
25
Things to Consider for Ultrafiltration Profiling
Does the patient have difficulty with fluid removal?
Have the MD answer these questions:◦ What UF rates can the patient tolerate?◦ Will the patient require periods of minimum UF? ◦ How will patient co-morbidities affect fluid removal?◦ What type of profile would be best suited for the
patient?
26
Individualize the Prescription Based Upon the Patient’s Treatment History
Determine when the patient typically demonstrates symptoms. Beginning – mid – end of treatment?
Does the patient need minimum UF to complete the treatment?
Evaluate the pre treatment systolic blood pressure (SBP)
Evaluate the patient’s weight gains between treatments
27
Choosing the Right UF Profiles
A profile that begins with the highest UF that can be tolerated by the patient which then decreases to a minimum will work for patients:
With large weight gains between treatments Who become hypotensive late in treatment Who cramp late or at the end of treatment With large weight gains between treatments and present with an elevated BP
Linear Progressive
Step Step
28
Choosing the Right UF Profiles Consider a profile with varying steps for patients who:
Need a gradual increase in UF at the beginning of the treatment to support low BP or cardiac output
Need short intervals of minimum UF to allow for plasma refill
Have difficulty shifting fluid into the vascular space (elderly, diabetic or unstable)
Cramp or are hypotensive randomly during treatment
29
Case Studies
How to select a UF profile for a patient
30
A patient weight gains typically of 3-4 kg and
experiences moderate to severe leg cramps during
the last 30 minutes of treatment
31
220
200
180
160
140
120
100
80
60
40 30
60 90 120 150 180 210 240
Patient tolerates fluid removal (higher UF) at the beginning of
treatment
Symptoms are relieved at the
end of treatment with a lower UF
UF Profile
Systolic B
P
Time in Minutes
32 S
ystolic BP
220
200
180
160
140
120
100
80
60
40 30 60 90 120 150 180 210 240
1.8 Kg/h
1.0 0.7
0.3
Step profiles allow for dramatic decreases in UF.
Lower UF at the middle and end of treatment will reduce
the patient’s symptoms
Fluid overloaded patients benefit from
aggressive UF at the beginning of the
treatment
UF Profile
Time in Minutes
33
Second patient arrives with a systolic blood pressure of 85 and a weight gain of 3 Kg. If her SBP
falls below 75 she becomes symptomatic
34
220
200
180
160
140
120
100
80
60
40 30 60 90 120 150 180 210 240
Time in Minutes
Systolic B
P
Less UF should be used at the beginning of
treatment while the SBP is low. Increase the UF during periods when the
SBP is higher Decrease the UF toward the end of treatment as the
patient approaches her
dry weight to prevent symptoms
35
220
200
180
160
140
120
100
80
60
40 30 60 90 120
150 180 210 240
Time in Minutes
Systolic B
P
Using a Step Profile, you can create multiple minimum UF
periods which will allow plasma refill to occur.
Decrease the UF toward the end of treatment as the patient approaches her dry weight to
prevent symptoms
36
A woman patient is hypertensive and diabetic. She has large fluid gains of 4-6 Kg between treatments and has symptoms of hypotension about 45 minutes into the treatment as well as mid and late treatment
37
Assessment and Plan Assessment:
◦ Large fluid gains◦ Severe hypotensive episodes◦ Poor plasma refill
Plan◦ Support plasma refill, especially during the first part
of the treatment ◦ Prevent hypovolemia ◦ Consider conductivity profiling in addition to UF
profiling
38
220
200
180
160
140
120
100
80
60
40 30 60 90 120 150 180 210 240
Time in Minutes
Sys
tolic
BP
Arrows indicate
plasma refill times
Utilize a Conductivity
profile to support solute removal
39
220
200
180
160
140
120
100
80
60
40 30 60 90 120 150 180 210 240
Sys
tolic
BP
Time in Minutes
UF and Conductivity Profiling can be used simultaneously
with similar step curves
40
220
200
180
160
140
120
100
80
60
40 30 60 90 120 150 180 210 240
UF and Conductivity Profiling can be used simultaneously
with similar progressive curves
Time in Minutes
Systolic B
P
41
Summary of UF Profiling Allows unlimited variation of ultrafiltration rates so that fluid can be removed from the vascular space while preventing symptoms
Allows periods of automatic plasma refilling to allow adequate fluid removal
Decreases the patient’s symptoms May be used simultaneously with conductivity profiling
42
References
Heinrich, W.L. & Victor, R.G., “Autonomic Neuropathy and Hemodynamic Stability in End-Stage Renal Disease Patients”, Principles and Practice in Dialysis, Williams and Wilkins, Baltimore, 1994.
Wilson, S., Alvarez, D., A Primer on Ultrafiltration Profiling and Sodium Modeling for Dialysis Patients, Contemporary Dialysis and Nephrology, April 2000, pp 34-36.
Bonomini, V., Coli, L., Scolari, M.P., Profiling Dialysis: A New Approach to Dialysis Intolerance, Nephron 1997; 75:1-6
Leunissen, K.M.L., Kooman, J.P., van der Sande, F.M., van Kuijk, W.H.M., Hypotension and Ultrafiltration Physiology in Dialysis, Blood Purif 2000; 18:251-254
Oliver, M.J., Edwards, L.J., Churchill, Impact of Sodium and Ultrafiltration Profiling on Hemodialysis Related Symptoms, J Am Soc Nephrol 12: 151-156 2000
Jensen, B.M., Dobbe, S. A., Squillace, D.P., McCarthy, J.T., (April 1994) Clinical Benefits of High and Variable Sodium Concentration Dialysate in Hemodialysis Patients, ANNA Journal, Vol. 21, No. 2.
43
References
Gambro Basics 1 Gambro Education 1994
Petitclerc, T. and Jacobs, C. Dialysis sodium concentration: what is optimal and can it be individualized? , Nephrol Dial Transplant Editorial Comments1995, 596-599.
Coli, L., Ursino, M., Dalmastri, V., Volpe, F., LaManna, G., Avanzolini, G., Stefoni, S., Bonomini, V., A simple mathematical model applied to selection of the sodium profile during profiled haemdialysis, Nephrol Dial Transplant (1998) 13:404-416
Donauer,J., Kolblin, D., Bek, M., Krause, A., Bohler, J., Ultrafiltration Profiling and Measurement of Reletive Blood Volume as Strategies to Reduce Hemodialysis-Related Side Effects, AJKD, Vol 36, No 1 (July), 2000:pp115-123
Stiller, S., Bonnie-Schorn, E., Grassmann, A., Uhlenbusch-Korwer, Mann, A Critical Review of Sodium Profiling for Hemodialysis, Seminars in Dialysis, Vol 14, No 5 (September-October) 2001 pp. 337-347
Locatelli, F., DiFilippo, S., Manzoni, C., Corti, M., Andrulli, S., Pontoriero, G., Monitoring sodium removal and delivered dialysis by conductivity, The International Journal of Artificial Organs/Vol. 18/no. 11, 1995/pp716-721