Ultrafiltration. Complications of hemodialysis

(intradialytic events)

Prof. Ryszard Grenda MD, PhD

Deparment of Nephrology, Kidney Transplantation & Hypertension

The Children’s Memorial Health Institute, Warsaw, Poland

CKD vs HD

HD improves some of them

HD worsens some of them

CKD- related symptoms

and comorbidities

Intradialytic complications

Intradialytic hypotension is the most common event occuring predominantly > 2 hours of HD session

What & when ? – staff’s perspective

What, when, for how long? – patients’ perspective

Intradialytic hypotension

Up

Down

Up

4% - magic treshold

still not dry weight dry weight

beyond HD

intra-HD

before HD

Osmotic agent vs controlled water removal vs α1-(adrenergic) receptor agonist

5% albumin To flush or not to flush?

Mechanistic, device-provided techniques

to prevent hypotension

Brain & HD

Cytotoxic brain oedema

↑water transport vs ↓urea transport

High BUN

Intervention:

- 0.5- 1,0 g/kg 20% mannitol

- Slow HD clearance

High glucose dialysate

(717 mg/dL)

Prevention:

- elective low HD clearance (max kt/V : 0,6 or

↓ of BUN ≤ 40% from baseline)

-short HD

- 0.5- 1,0 g/kg 20% mannitol

(from the beginning of HD)

↑↓ blood pressure ↑↓ urea concentration ↑↓ magnesium concentration

Acute intradialytic hemolysis

Key summary points

1. The most commmon intradialytic adverse events, recognized by dialysis staff are: hypotension, cramps, dizziness, nausea, headache and vomiting. They appear mainly in the second time-part of HD session, however disappear in a couple hours after HD session.

2. The most common hemodialysis-related event recognized by the patients is fatigue. This one lasts for a long time, sometimes until the next day.

3. Reduced cardiac output and reduced peripheral resistance are combined underlying mechanism of intradialytic hypotension, which may be prevented by variable medical or technical interventions.

4. Dialysis disequilibrium syndrome, with severe headache, confusion and convulsions should be rapidly differentiated with cerebrovascular event and malignant hypertension

5. Intradialytic hemolysis is life-threating event, requiring immediate step-wise management, aimed to stop the return of hemolyzed blood to the patient, decrease the hyperkaliemia and supplement the blood loss by transfusion

6. There are several specific maneuvers in dialysis technique, related to hemodialysis clearance and UF, as well as dialyzate content and temperature, which have potential to minimize the risk of intradialytic events.

Intradialytic complications - cases

Case 1. 4-years-old girl, myelomeningocoele, end-stage renal failure, ventriculo-peritoneal shunt, attempt to create AV-fistula failed currently HD, 3 x week, permanent catheter

Current event:

HD after week-end (two - days interval from last HD)

Participating in family party during week-end

Two hours after HD initiation: severe headache, vomiting; patient disoriented

Question 1

What is the most probable cause of this event:

a. Sudden hypertensive crisis

b. Disequilibrium syndrome

c. Hyponatremia

d. Cerebral event due to the failure of ventriculo-peritoneal shunt

Question 2

What would you do first?

a. Stop HD, go for urgent EEG

b. Stop HD, go for urgent brain MRI

c. Give diazepam iv.

d. Slow blood pump, give iv. 20% mannitol 0.5 g/kg

Comment

All distract possibilities listed in question 1 were probable, however:

- Event was related to HD

- Patient has probably high pre-dialysis BUN (family party, diet non-compliance, two days between HD sesions)

- The radiologic examinations might be done, if mannitol would not be effective

Case 2. 15-years-old boy, hemodialyzed for 2 years, stable follow-up

Current event

Routine HD session; after 3 hours :

- sudden nausea,

- vomiting,

- abdominal pain,

- patient says: „I feel thrills of my heart”

Question 1

What do you think, it might be?

a. The begining of acute dyspepsia

b. Sudden hypertensive crisis

c. Acute hemolysis

d. Symptoms of peptic ulcer

Blood pressure was normal, no history of wrong food, nor peptic ulcer

Question 2.

What would you do first?

a. Slow blood pump, give resin (Resonium) orally

b. Just change the dialyzer

c. Give bicarbonates iv.

d. Clamp tubes (to prevent blood return to the patient); immediately check serum K+, free Hb concentration or LDH, Hct.

Comment

Symptoms suggested and basic tests confirmed the intra-dialytic hemolysis.

This is life-threating event, therefore:

- Immediate preventing blood return is crucial

- Immediate high - potassium fighting is crucial, including new HD with low-potassium –containing dialysate

- Blood tranfusion [sometimes „universal” blood (0/AB/Rh-) with no cross-match test] will be necessary (depending on blood loss)

- Apart from that, the further investigation of the causes of hemolysis (mechanical vs chemical) is mandatory

Case 3.

4-years-old girl, ESRD due to congenital nephrotic syndrome, completely anuric, hypertensive; non-compliant in terms of fluid intake

Current event.

Routine HD on Monday (two-days interval after last HD); weight gain about 8% of body weight; hypertensive

After 3 hours of regular HD, she collapsed; blood pressure 80/60; sweating; disoriented

Question 1 What would you do first ? a. give 30 ml of 10% saline b. give 100 ml of 5% albumin c. give dopamine 6 µg/kg/min d. give 100 ml of 0.9% saline

Question 2. What should be done for further diagnosis? a. brain CT scan b. ECHO 2D cardiography c. USG-Doppler of native kidneys d. serum troponine

Question 3. What would be preventive measures for intradialytic hypotension? a.improvement of fluid compliance b. better targeting of dry weight c. intradialytic sodium/UF profilling d. all above

Comment - intradialytic hypotension is the most common adverse event of HD - anuric, non-compliant patients are at risk - LV hypertrophy is common in these patients - concentrated (10%) saline or 5% albumine are not better than normal (0.9%) saline for direct intervention - UF and sodium profilling are helpful in most patients - if not, every-day HD with carefully planned UF should be introduced

1982 (34 years ago) Who is he?