Intradialytic Hypotension

Fadel A. AlRowaie , MD ,FACP ,FNKFAssistant Professor of Medicine (KSAU-HS)

Consultant Nephrologist Head of Nephrology (KFMC)

Outline

• Introduction– Definition– Epidemiology – Clinical consequences

• Pathogenesis– Water movement and vascular refilling– Cardiovascular response to UF

• Interventions to reduce intra-dialytic hypotension

Schreiber MJ Jr. Am J Kidney Dis. 2001 Oct;38(4 Suppl 4):S37-47

Clinical scenarioUF stoppedQb reducedIVF 250 cc 0.9NS

Introduction

Hypotension that require nursing intervention or medical treatment occurs in 10-30% of hemodialysis treatment (HEMO study :18.3% vs. 16.8% )

McCausland FR, et al .Am J Nephrol. 2013;38(5):388-96

Intra-dialytic Hypotension

(IDH) is defined as a decrease in systolic blood pressure by ≥20 mm Hg or a decrease in MAP by 10 mm Hg associated with symptoms & need for nursing intervention

K/DOQI Workgroup. K/DOQI clinical practice guidelines for cardiovascular disease in dialysis patients. Am J Kidney Dis. 2005 Apr;45(4 Suppl 3):S1-153

Kooman J, Basci A et al. EBPG guideline on haemodynamic instability. Nephrol Dial Transplant. 2007 May;22 Suppl 2:ii22-44.

Clinical significance

• Increased mortality• Access thrombosis• Under-dialysis and volume overload• Organs ischemia ( MI , CVA and ischemic

bowel)• Increase nursing intervention

Always consider and exclude the following serious conditions:• Arrhythmia• Pericardial tamponade• Valvular disorders • Myocardial infarction• Hemolysis & hemorrhage• Septicemia• Air embolism

Shoji T. et al . Kidney Int. 2004 Sep;66(3):1212-20

Vascular access thrombosis is more frequent with grafts than with fistulas.

Chang T I et al. JASN 2011;22:1526-1533

©2011 by American Society of Nephrology

Subjects with more frequent episodes of intradialytic hypotension are more likely to experience vascular access thrombosis.

Chang T I et al. JASN 2011;22:1526-1533

©2011 by American Society of Nephrology

Pathogenesis of IDH

DialyzerECFICF

Water movement Step 1

Step 2

Step 3

Loss of urea/H2O

280

Osmolality 320 mosmol/kg

Osmolality 320 mosmol/kg failing to 290 mosmol/kg as diffusion occurs

Water movement during hemodialysis

Stroke volume X Heart rate

Cardiovascular responses to plasma volume depletion.

Reilly R F CJASN doi:10.2215/CJN.09930913

©2014 by American Society of Nephrology

Patients at risk of IDH• 65 years or older age• DM• Patients with CVD:

– LVH and diastolic dysfunction with or without CHF– LV systolic dysfunction and CHF– Valvular heart disease– Pericardial disease (constrictive pericarditis or pericardial effusion)

• Poor nutritional status and hypoalbuminemia• Hyperphosphatemia• Uremic neuropathy or autonomic dysfunction due to other causes• Severe anemia• Patients requiring high volume ultrafiltration; more than expected

interdialytic weight gain• Patients with predialysis SBP of <100 mm Hg

Acute Management of IDH

• Reduce the rate or stop the ultrafiltration • Place patient in Trendelenburg position• Reduce blood flow • IVF 250 ml of 0.9 % NS bolus (can be repeated) / albumin &

manitol are alternatives• Exclude serious condition

Knoll GA . J Am Soc Nephrol. 2004 Feb;15(2):487-92

Albumin Vs. Saline for treatment of IDH

Interventions to reduce intra-dialytic hypotension

• Patient related intervention – Accurate setting of the "dry weight“– Minimize inter- dialytic weight gain– Reduction of salt intake to 2g/ 90 mmol Na per day (6 g/d NaCl)– Avoidance of food during dialysis– Avoid antihypertensive medicines on dialysis day

• Dialysis related intervention– High dialysate Na / Na profiling– Sequential ultrafiltration and isovolemic dialysis – Blood volume monitoring & biofeed back dialysis– Low dialysate temperature – Bicarbonate buffer– High dialysate Ca++– Hemofiltration and hemodiafiltration– Prolonged & frequent dialysis

• Pharmacological intervention– Midodrine– Carnitine

DialyzerECFICF

Water movement Step 1

Step 2

Step 3 Iso-osmotic loss of solutes/H2O

Osmolality 320 mosmol/kg

Osmolality 320 mosmol/kg with raising plasma oncotic pressure

Water movement during isolated ultrafiltration

Change in Na & weight post dialysis

Reddan DN et al .J Am Soc Nephrol. 2005 Jul;16(7):2162-9

Nesrallah GE et al.Nephrol Dial Transplant. 2013 Jan;28(1):182-91

Biofeedback dialysis for hypotension and hypervolemia: a systematic review and meta-analysis

• Guideline 3.1.2a Individualized, automatic BV control should be considered as a second-line option in patients with refractory IDH (Evidence level II).

• Guideline 3.1.2b Manual adjustment of ultrafiltration according to a fixed protocol based on changes in blood volume should not be performed (Evidence level II).

Kooman J, Basci A et al. Nephrol Dial Transplant. 2007 May;22 Suppl 2:ii22-44.

Low dialysate temperature

There are two different ways of reducing dialysate fluid temperature:• Empiric fixed reductions of dialysate

temperature• Isothermic dialysis, a technique in which body

temperature remains constant via the use of a biofeedback temperature-controlled device

Jost CM et al.Kidney Int. 1993 Sep;44(3):606-12.

Selby NM et al .Nephrol Dial Transplant. 2006 Jul;21(7):1883-98

Bicarbonate dialysate vs. Acetate

44%

56%

The frequency of IDH during HD using acetate dialysate

Non IDH IDH

98%

2%

The frequency of IDH during HD us-ing bicarbonate dialysate

Non IDH IDH

Thaha M. et al.Acta Med Indones. 2005 Jul-Sep;37(3):145-8

High calcium dialysate & Ca profiling

Kyriazis J et al. Kidney Int. 2002 Jan;61(1):276-87

Alappan R et al. Am J Kidney Dis. 2001 Feb;37(2):294-9.

The addition of High Dialysate Ca to midodrine and/or cool dialysate further improves blood pressure in patients with IDH. However, this therapy did not reduce symptoms or interventions required for IDH. In addition, hypercalcemia complicated this therapy in 22% of the patients.

Midodrine

• Midodrine is an oral prodrug with selective α-1 adrenergic agonist activity.

• The drug was released into clinical practice in 1996 as a new treatment for patients

with symptomatic orthostatic hypotension.

• is rapidly absorbed in the GIT and converted to the active metabolite,

desglymidodrine, in the systemic circulation

• The prodrug achieves peak levels in 60 minutes. The absolute bioavailability of

desglymidodrine is 93% for oral tablets, and it reaches peak levels in approximately

60 to 90 minutes.

• Excretion of the drug is primarily renal , the half-life of desglymidodrine, is 3.5 hours

on HD & 9 hours on nondialysis days

• The major adverse events were piloerection (13%) and pruritis (10%)

Perazella MA.Am J Kidney Dis. 2001 Oct;38(4 Suppl 4):S26-36

Prakash S. Nephrol Dial Transplant. 2004 Oct;19(10):2553-8

Comparison between various interventions to prevent IDH

Dheenan S. Kidney Int. 2001 Mar;59(3):1175-81

Dheenan S. Kidney Int. 2001 Mar;59(3):1175-81

o First-line approach o Dietary counselling (sodium

restriction).o Refraining from food intake during

dialysis.o Clinical reassessment of dry

weight.o Use of bicarbonate as dialysis

buffer.o Use of a dialysate temperature of

36.5°C.o Check dosing and timing of

antihypertensive agents

Second-line approach o Try objective methods to assess dry

weight.o Perform cardiac evaluation.o Gradual reduction of dialysate

temperature from 36.5°C downward (lowest 35°C) or isothermic treatment (possible alternative: convective treatments).

o Consider individualized blood volume controlled feedback.

o Prolong dialysis time and/or increase dialysis frequency.

o Prescribe a dialysate calcium concentration of 1.50 mmol/l.

Third-line approach (only if other treatment options have

failed)

o Consider midodrine.o Consider l-carnitine supplementation.o Consider peritoneal dialysis.

EBPG guideline on haemodynamic instability

Kooman J, Basci A et al. Nephrol Dial Transplant. 2007 May;22 Suppl 2:ii22-44.

Dialysate sodium

Guideline 3.2.1 :Although sodium profiling with supraphysiological dialysate sodium concentrations and high sodium dialysate (≥144 mmol/l) are effective in reducing IDH, they should not be used routinely because of an enhanced risk of thirst, hypertension and increased inter-dialytic weight gain (Evidence level II).

falrowaie@kfmc.med.sa @fadelrowaie