What is sodium modeling in hemodialysis patients?

Causes of Intradialytic hypotension(IDH) 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 sepsis Intradialytic venous pooling Core body temp.↑ Anemia. Reduced plasma refilling rate Reduced ECV Impaired Vasoconstriction Hemorrhage Intradialytic Hypotension n 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) Heart problems Myocardial Infarction Structural heart dis. Arrythmias Pericardial tamponade Hemolysis Dialyzer Rxn Air embolism

Water movement during standard hemodialysis Intracellular fluid Extracellular fluid Dialyzer step3 Water movement step1 280 Loss of urea and water Osmolality 320 mosm/kg Falling to 290mosm/kg as diffusion occurs Osmolality 320 mosm/kg n step2 Compensatory refilling

Fluid removal Plasma refilling

Increased risk of hypotension Fluid removal Fluid removal Low Na 130-135 meq/l Na

Historically the dialysate Na was maintained at hyponatremic level, 130-135: To prevent: Intradialytic hypertension Thirsty Interdialytic weight gain

Disadvantages of dialysates with low sodium concentration: Increased risk of hypotension Increased risk of intradialytic cramps Increased risk of dialysis disequilibrium syndrome

Increased intracellular urea removed by dialyzer urea sequestration in tissue fluid Effluent Dialysate Increased intracellular osmolarity Inffluent Dialysate fluid Na

High dialysate sodium: 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

Fluid removal Plasma refilling Na Low Na >145 meq/l Na

Different patterns of sodium modeling 145-155 meq/lit Na concentration 135-140 meq/lit Hours after dialysis initiation

Dialysate Na should be regulated based on serum 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

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

Fluid Spaces in the Body Average weight Male 70 kg or 154 lbs. BONE, MUSCLE, FAT 60% of Total Body Weight is 42 liters of water VASCULAR SPACE 4 LITERS WATER, 5% Extracellular INTERSTITIAL SPACE 11 LITERS WATER, 15% INTRACELLULAR SPACE 27 LITERS WATER 40%

Two Basic Reasons That Patients End up With Dialysis Symptoms During Treatment 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  

Symptom Etiology With Constant Ultrafiltration Symptoms of Volume loss: Hypotension Cramping Dizziness Nausea Vomiting Shock Ultrafiltration (UF) removes water volume from the blood into the dialysate, causing hypovolemia

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

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

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? Read the slide

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

Choosing the Right UF Profiles Linear Progressive 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 Step Step I would need an explanation or a for instance for the 1.5 times hourly UF rate I don’t understand what you mean.

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

How to select a UF profile for a patient Case Studies How to select a UF profile for a patient

A patient weight gains typically of 3-4 kg and experiences moderate to severe leg cramps during the last 30 minutes of treatment Read the slide.

Symptoms are relieved at the end of treatment with a lower UF Patient tolerates fluid removal (higher UF) at the beginning of treatment 220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 Symptoms are relieved at the end of treatment with a lower UF Systolic BP UF Profile Time in Minutes

220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 Fluid overloaded patients benefit from aggressive UF at the beginning of the treatment 1.8 Kg/h 1.0 0.7 0.3 Systolic BP Step profiles allow for dramatic decreases in UF. Lower UF at the middle and end of treatment will reduce the patient’s symptoms UF Profile Time in Minutes

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

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 220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 Decrease the UF toward the end of treatment as the patient approaches her dry weight to prevent symptoms Systolic BP Time in Minutes

220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 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 Systolic BP Time in Minutes

A woman patient is hypertensive and diabetic 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

Assessment and Plan Assessment: Plan 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

220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 Utilize a Conductivity profile to support solute removal Systolic BP Arrows indicate plasma refill times Time in Minutes

220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 UF and Conductivity Profiling can be used simultaneously with similar step curves Systolic BP Time in Minutes

220 200 180 160 140 120 100 80 60 40 30 90 150 210 240 Systolic BP UF and Conductivity Profiling can be used simultaneously with similar progressive curves Time in Minutes

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 Read the slide.

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.

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