How I manage volume in

hemodialysis patients :

Pro-BVM (no fixed dry weight)

Dr. Luc Radermacher

Fluid balance in HD

Mo Tu We Th Fr Sa Su Mo

Weight

DW

Hypervolaemia

Euvolaemia

Hypovolaemia

HD HD HD

DW – Definition

• « The reduction of BP to hypotensive levels during UF, representedthe achievement of a dry weight status. » Thomson GE et al. Arch Intern Med. 1967; 120:153–167

• « DW is defined as the lowest tolerated postdialysis weight achieved

via gradual change in postdialysis weight at which there are minimal signs or symptoms of hypovolemia or hypervolemia »Agarwal R, Weir MR. Semin Dial. 2017 Nov;30(6):481-488.

→ DW is an estimated value (not an accuratecalculated value) based on clinical judgment.

DW variations:

• Weekly / Monthly weight and DW variation :– Changes into caloric diet

– Changes into physical activity

– Other hypercatabolic / anabolic conditions

– « Third sector »

• Daily weight and DW variations:– 24h physiological weight variations : food time, physical activity, bladder content,

constipation, …

– Extracorporal weight variation factors : clothes & shoes, prostheses, diaper and urine bag, scales, weighing errors, …

DW is highly variable

Optimal fluid balance in the real

world HD

Mo Tu We Th Fr Sa Su Mo

Real

weight

« Moving » DW

Hypervolaemia

Euvolaemia

Hypovolaemia

HD HD HD

Fluid balance with a fixed DW

Mo Tu We Th Fr Sa Su Mo

Real

weight

Fixed DW

Hypervolaemia

Euvolaemia

Hypovolaemia

HD HD HD

Hypotension

Syncope

Cramps

APE

HD discomfort principal cause :

Excessive volume contraction

Since blood volume is inversely proportional to hematocrit, changes in

hematocrit directly reflect changes in blood volume

=> Blood volume can be tracked online by an

hematocrit monitoring : BVM

BVM profiles

UF biofeedback guided by

BVM : the controlled UF

Objective: optimize the UF to the vascular "refilling" in real time

– Control volume contraction and reduce discomfort associated with an excessive UF

– Improve control of H2O / Na overload regardless of blood pressure

UF control specific settings 1:

Max UF flow rate

UF control specific settings 2:

DW deviation

UF control specific settings 3 :

Critical RBV

• « An individual RBV limit exists for nearly all patients. In most IME-prone patients, these RBV values were stable with only narrow variability, thus making it a useful indicator to mark the individual window of haemodynamic instabilities. »

UF control specific settings 3 :

Critical RBV

• Initial : 90% (> 75y) – 88% (< 80y)

• Reduce at each session by 1-2% until the first symptoms (symptomatic hypotension, cramps, ...). Then go up 1-2%.

• Technical limitations : 75 – 95%

Critical RBV variability

•

70

75

80

85

90

95

100

0 10 20 30 40 50 60 70 80 90 100

VS

R C

rit.

(%)

Age (années)

VSR critique selon l'âgeCHR de la Citadelle - Liège

Octobre 2015

Hommes

Femmes

Tendance Hommes

Tendance Femmes

Critical RBV variability

• Acute phenomena (sepsis, ischemia,…) and any unusual state of stress (surgery preop-postop, aggression, etc.): ↑ crit. RBV

• External temperature ("seasonal effect") and internal temperature (dialysate) changes

• Treatment changes (antihypertensives, nitrates, anti-arrhythmics, etc.).

• …etc…

UF controlContribution in fluid balance

management

• Optimizes the DW out of any clinical sign and prevents acute episodes of overload (Pulmonary edema, ...)

• DW reduction is made possible despite of hypotension especially in cardio-renal syndromes

• Differential diagnosis of volo and non-volo-dependent HT

• Differential diagnosis of dyspnoea

• Reduced need for paraclinical procedures → Cost reduction

• “It's the machine that decides whether to draw. It depends on what you can give”. → Stop in time consuming discussions around the DW → Improvement in UF compliance

UF control : A better control of HD discomforts

• Anticipation of hypotensive episodes

• Disappearance of rebellious symptomatic hypotension

• Reduction of cramps, nausea, and headaches

• Disappearance of rebel cramps and uncontrollable vomiting

→ Improvement of hemodynamic stability and preservation of Residual Kidney Function (RKF)

→ Improvement in session comfort, session compliance and psychological acceptance

→ Improvement of overall efficacy

UF control : Clinical and technical limits

• Not applicable in case of transfusion or active bleeding

• Important artifacts in case of blood flow problems

• Reserved for bipuncture

• Crit RBV 75 - 95%Max UF deviation ± 1000 ml, and/or 50% of the total programmed UFMax UF flow rate 2800 ml/h

Conclusions

• For an optimal fluid balance control in HD :– Minimize oral sodium and fluid intake

– Optimize sodium dialysate

– Preserving RKF and diuresis

– Optimize UF to the moving DW

• BVM guided UF best follows the high variability of DW Improvement of hemodynamic stability, of fluid balance control and of QoL Cost effective.

BVM in the future ?

• Expand technical limits :

– Max UF rate possibilities (3000 – 3500 L/h ?)

– DW deviation possibilities (± 2000 ml ?)

– Expand critical RBV possibilities (95 – 65 % ?)

– Expand to unipuncture.

• Towards a complete “moving DW” hemodialysis, with the sole objective of an ideal BVM curve. No need to weigh our patients anymore ?