Intra dialytic hypotension

1. Intradialytic Hypotension
By
Alaa Sabry, MD, FACP
Professor Of Nephrology, Mansoura University

2. Clin J Am Soc Nephrol. 2014 Apr 7; 9(4): 798–803.
• A 65-year-old man was on hemodialysis since 2006 type II
diabetes mellitus.
• Hypertension, coronary artery disease, moderate concentric left
ventricular hypertrophy (LVH).
• Medications metoprolol, lisinopril, gabapentin, cinacalcet, calcium
acetate, lanthanum carbonate , and omeprazole.
• Laboratory (sodium=139 mEq/L, potassium=4.6 mEq/L, calcium
8.9=mg/dl, phosphorus=6.5 mg/dl, parathyroid hormone=558
pg/ml, albumin=3.4 g/dl, and hemoglobin=11.5 g/dl ).
• Dialysis : 4 hours.
• Dialysate (2.0 mEq/L potassium and 2.5 mEq/L calcium with
Bicarbonate acid concentrate.
• Kt/V was 1.49.
• His average interdialytic weight gain was 4 kg per treatment.
• Dry weight was 98.5 kg.

3. • He developed intradialytic hypotension (IDH) episode .
• His predialysis temperature was 36.2°C., he felt poorly and
was diaphoretic.
• In response, saline was administered, ultrafiltration was
stopped, and the patient was placed in a reclining position
with resolution of the hypotension.
• He had a previous history of IDH and as a result, was already
being dialyzed with cool dialysate (temperature=35.5°C) and
ultrafiltration modeling. Given the apparent absence of signs
of volume, his dry weight was increased to 99.5 kg.
• Despite this increase, 9 days later, he developed another
episode of IDH .
• On this day, his predialysis temperature was 35.8°C. Once
again, his dry weight was increased (to 100.5 kg.)
Clin J Am Soc Nephrol. 2014 Apr 7; 9(4): 798–803.

4. complications
IDHo- IDHr
Cramps
Arrhythmia
Chest&
back pain
Itching
Seizures
Dialyzer
reaction
Hemolysis
Air
embolism
Disequilibrium
syndrome- N&V-
Headache

5. Definition
IDH remains one of the most vexing management
challenges for nephrologists.
It has three essential components:
1)A drop in BP generally defined as ≥20 mmHg
systolic BP or ≥10 mmHg in mean arterial pressure.
2) The presence of symptoms of end organ
ischemia.
3) An intervention carried out by the dialysis staff .
Agarwal R. Curr Opin Nephrol Hypertens 21: 593–599, 2012
IDH complicates approximately 15%–30% of all
hemodialysis treatments

6. Intradialytic Hypotension (IDH)
mechanism?
Patient factors
 Cardiac disease
- Systolic dysfunction
- Diastolic dysfunction
 Arrhythmias
 Pericardial disease
 Autonomic neuropathy
 Interdialytic weight gain
 Food ingestion in dialysis
 Antihypertensive agents
 Anemia (< Hb 7.0g/dL)
Dialysis procedure factors
 Ultrafiltration, solute removal
(Slower refilling of plasma volume
)
 Dialysate Temp
Dialysate composition
 Low sodium (<138mEq/L)
 Low calcium
 High magnesium
 Acetate

7. • It is important to rule out acute conditions that
can lower BP.
• 1- Infections (especially involving the access if
the patient has a permcath or a graft),
pneumonia, cellulitis, and osteomyelitis.
• 2- Blood loss.
• 3- New onset of cardiac arrhythmias (new onset
of cardiac arrhythmias).
• 4- Pericardial effusion.

8. • Annoying complains (cramping and postdialysis fatigue)
• Early termination of dialysis : inadequate fluid removal
and reduced efficacy of the dialysis therapy.
• Suboptimal ultrafiltration over the long term may lead to
volume overload and interdialytic hypertension.
perpetuate left-ventricular hypertrophy and reduce
arterial compliance, which may provoke more IDH.
• Vascular access thrombosis
• Ischemia of cerebral, mesenteric, and coronary
circulations.
• IDH may affect health-related quality of life .
• Increased medical and nursing care.
Chang TI, et al.J Am Soc Nephrol 2011; 22:1526–1533.
Flythe JE., et al Kidney Int 2011; 79:250–257.

9. Pathogenesis

10. Pathogenesis
Plasma volume depletion

12. What happens in a normal individual that is
subjected to PV depletion
Large degree of fluid removal
Effective plasma volume depletion
Stimulation of low pressure baroreceptors
Stimulate efferent sympathetic pathway
Increase in SVR
Increase in venous return
Increase in stroke volume
Increase in CO

13. PATHOPHYSIOLOGY OF INTRADIALYTIC
HYPOTENSION
 High ultrafiltration rates.
Impaired cardiovascular defenses

14. High ultrafiltration rates.
• During a dialysis procedure, several liters of fluid
are ultrafiltered.
• This volume of ultrafiltrate often exceeds the
entire plasma volume pool.
• Plasma volume is partially restored by refilling the
intravascular pool from the interstitial fluid
compartment.
• When dry-weight is probed, the interstitial fluid
space is reduced. As a result IDH frequency is
increased.

17. Why do some ESRD patients not compensate
appropriately to ultrafiltration?
It can result from autonomic or baroreceptor
failure or disturbed cardiac function.
Diabetes, aging, and uremia can cause
autonomic and baroreceptor dysfunction,
leading to excessive venous pooling and
aberrant vasodilation.
Cardiac diseases, such as LVH, ischemic heart
disease, myocardial stunning, contribute to
cardiac dysfunction with IDH .
Selby NM, McIntyre CW.: The acute cardiac effects of dialysis. Semin Dial 20: 220–228, 2007

18. Impaired Baroreflex

19. There were gradated increases in endotoxemia with
increasing CKD stage
predialysis endotoxin correlated with dialysis-induced
hemodynamic stress relative hypotension

20. 400 BC, when Hippocrates stated, “death sits in the bowels.”

21. TMAO = Trimethylamine-N-oxide (TMAO)
PCS = p-cresyl sulfate
IS= indoxyl sulfate

22. How to assess volume status in
hemodialysis patients ?

23. 1- Dry Body Weight

24. 1- Dry Body Weight
• 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” .
• Sinha AD,. Semin Dial 22: 480–482, 2009
• Probing to achieve dry weight should be done with caution given the
potential adverse consequences of hypotension in an ESRD population
with multiple comorbidities that predispose to end organ ischemia.
• Achievement of even a relatively small reduction in dry weight (1 kg) in
hypertensive hemodialysis patients reduced systolic and diastolic BPs by
6.6 and 3.3 mmHg, respectively, in the Dry Weight Reduction in
Hypertensive Hemodialysis Patients trial .
Agarwal Ret al 53: 500–507, 2009 .

25. 2- Peripheral edema

26. • The presence or absence of pitting pedal edema
is perhaps the simplest physical sign to elicit.
• Fallacies :
• 1- Edema may be due to excess vascular
permeability .
• 2-Stasis .
• 3-Vasodilator drugs including dihydropyridines.
• The utility of this simple physical sign as a
marker of hypervolemia in HD patients is
unknown.
2- Peripheral edema

28. 3-Hypertension

29. • Recently shown to be a poor predictor of the presence of
volume overload.
• 500 hemodialysis patients from eight centers and
measured predialysis BP and deviation of hydration status
from normal using multiple frequency bioimpedance.
• 13% of patients had hypertension but were not
hypervolemic.
• 10% of patients were hypervolemic but did not have
hypertension.
• This finding shows that hypertension does not always
equal hypervolemia and vice versa in hemodialysis
patients.
3-Hypertension

30. Clinical Methods
• Notwithstanding their widespread use, these
clinical methods fail to evaluate ECV status
accurately even when applied by a well-
educated and dedicated staff.

31. Assessment of Extracellular Fluid
Volume

32. 4- Measurement of body Fluid Volumes
A)-Tracers
• Deuterium and tritium dilution are preferred
means to measure TBW.
• Bromide, inulin, ferrocyanide, chloride, and
sucrose dilution yield data on ECV
• Volume B = tracer mass given⁄ tracer concentration in B.
• B= The compartment of interest.
• Dilution methods are considered as gold
standards for evaluating fluid status.

33. B-Whole-body bioimpedance
• The most promising of the techniques.
• Single frequency devices can only measure total body
water .
• Multifrequency devices measure both total body water
and extracellular water.
• Whole-body bioimpedance is based on the assumption
that the body is a cylinder with uniform conductivity,
which is not true given that the limbs provide 90% of total
body resistance but only 30% of total body water.
Segmental devices that measure bioimpedance in the calf
do not suffer from this problem .
• Patients with pacemakers, stents, artificial joints, or
amputation(s) and patients who are pregnant are
prohibited to undergo bioimpedance analysis for safety
and/or performance issues.
Dou Y, et al . Semin Dial 25: 377–387, 2012

34. B- Bioimpedance
• (DW) is reached when two
criteria are satisfied:
• (i) Flattening of the curve
of calf extracellular
resistance (R0 ⁄Rt) over 20
minutes
• (ii) calf normalized
resistivity( qN ) is equal to
or greater than the lower
threshold of the normal
range seen in healthy
subjects (males, 0.183 Xm3
⁄ kg; females,0.20 Xm3
⁄kg). 1-flattening of R0 ⁄Rt curve over 20 minutes
2- ( qN ) in the normal range (males, 0.183 Xm3 ⁄ kg; females, 0.20 Xm3 ⁄ kg).

35. C- Relative Blood Volume (RBV)
Change
• The relative change of blood volume (DRBV) can be
calculated from Equations ( assuming that red blood cell
volume (RBCV) is constant during HD ).
• Online BV monitoring was suggested to evaluate the
fluid status of HD patients.
• Disadvantage:
• RBV was influenced by ultrafitration volume (UFV) and
UF rate (UFR).
• Dasselaar JJ,. ASAIO J 53(4:)479–484,2007
• RBV even increased by 2.4 ± 1.4% and 2.5 ± 0.8% during
the 1st and 2nd hour dialysis session even without
ultrafiltration
• Nette RW, Blood Purif 19(1:)33–38,2001
• A multicenter prospective study found that there were
no critical RBV reduction level for the appearance of
symptomatic hypotension in 123 HD patients
• Andrulli S, Am J Kidney Dis 40(6:)1244–1254,2002

36. D- Biofeedback technology
• Most biofeedback devices continuously monitor
blood pressure (BP) or infer plasma refilling from the
relative blood volume.
• Calibrated software can then automatically adjust
dialysate conductivity and/or ultrafiltration rates to
optimize the balance between fluid removal and
preservation of intravascular volume .
• Integrated mathematical modeling software can also
be used to achieve neutral or negative sodium
balance.

37. • Eight Trials .
• 716 Patients .
• All trials were open-label and at least four were
industry-sponsored.
• No study evaluated hospitalization and the
evidence for effect on mortality was of very low
quality.

38. • The frequency of IDH was lower among patient receiving biofeedback dialysis in all six
studies that reported this outcome

41. Crit-Line Intradialytic Monitoring
Benefit (CLIMB) Study

42. • A total of 227 patients were
randomized to Crit-Line
monitoring and 216 were
randomized to conventional
monitoring for 6 mo.
• Patients dialyzed with blood
volume monitoring over a 6-
month period versus controls
had higher mortality (8.7%
versus 3.3% (P 0.021) .
• Hospitalization rates were
also higher in the intervention
group.
Crit-Line Intradialytic Monitoring
Benefit (CLIMB) Study

43. E)-The Inferior Vena Cava Diameter
• The maximal IVCD during
quiet expiration and
inspiration (IVCDe; IVCDi)
and the collapsibility
index (CI) are calculated.
• Inferior vena cava (IVC)
diameter was measured
at the level just below
the diaphragm in the
hepatic segment .
• Inferior vena cava (IVC) is normally 1.5 to 2.5 cm in diameter
(measured 3 cm from right atrium).
• Inferior vena cava (IVC) normally collapses more than 50%
with inspiration.
• Collapse <50% suggests volume overload

44. D)-The Inferior Vena Cava Diameter
• A limitation of ultrasound measurement
• 1- Is user-dependent (significant degree of
intra- and interobserver variability ).
• 2-Affected by patient compliance and conditions
(e.g., intestinal gases may reduce visibility).
• Perhaps this indicates that it is not practically
feasible for routine hemodialysis use.
• 3-it is difficult to interpret in patients with heart
failure and tricuspid regurgitation.

45. D)- Lung Ultrasound
• Lung ultrasound can
evaluate extravascular lung
water by identifying B-
lines.
• Vertical artifacts arising
from the pleural line and
extending to the edge of
the screen that move
synchronously with
respiratory acts .
• its use has been validated
for the evaluation of acute
respiratory failure acute
and chronic heart failure .

46. • 71 consecutive patients undergoing HD.
• Ultrasound, bioimpedance and clinical
measurements were performed immediately
before and after (within 15 min) dialysis
sessions.
• A significant reduction in B-lines numbers
during the HD session, and the reduction in
B-lines correlated with weight loss due to HD.

47. E-Biomarker
Brain Natriuretic Peptide
• The precursor protein pro brain natriuretic peptide
(proBNP) is produced in cardiac myocytes.
• BNP is closely related to left ventricular (LV) mass
and LV dysfunction.
• BNP has been proposed as a biomarker of fluid
status.
• In HD patients, these biomarkers do not reliably
reflect ECV status, because cardiac stretch is not
well correlated with ECV.

48. Methods to assess ECV volume
vv

49. Management

50. Corrective steps to treat hypotensive episode
• Reduce the blood flow rate ???????
• Reduce the ultrafiltration rate
• Put the patient in Trendlenberg position ????
• Restoration of plasma volume
• Nasal oxygen
• Pressor agents
• Discontinue dialysis

51. Albumin Versus Saline ?

52. • Seventy-two patients .
• 37 to treatment sequence 1 (5%albumin to treat the first episode of IDH,
the second and third dialysis sessions with IDH were treated with normal
saline ).
• 35 to treatment sequence 2 (normal saline to treat the first dialysis
session with IDH, the second and third dialysis sessions with IDH were
treated with 5% albumin ).
• Effects of interventions:
• 5% albumin is not superior to normal saline for the treatment of
symptomatic hypotension in maintenance haemodialysis patients with a
previous history of IDH.
• There were no significant differences in the nursing time required to
treat IDH and the time required to restore BP.

53. INTERVENTIONS TO REDUCE THE
INCIDENCE OF IDH

54. Salt Restriction
NKF KDOQI guidelines recommend an upper limit of daily salt intake of 5 g(∼85
mmol of sodium) .

55. 1- Limiting interdialytic weight gain
• A common misconception that exists is that reduction in
interdialytic weight gain is achieved by restricting fluid, which
ignores the most basic principles of salt and water homeostasis.
• The main determinant of extracellular fluid volume is sodium.
• This process involves making informed and healthy food
choices, because only 15% of salt ingested in the United States
is added during the cooking process or at the table .
• Through dietary sodium restriction would provoke less
ultrafiltration and therefore lower hemodynamic stress during
dialysis.
• Limiting dietary sodium intake is therefore recommended
especially for patients who gain excess (>2 kg) weight in the
interdialytic period.

56. • Increasing dry-weight reduces the need to
ultrafilter, but it also risks volume overload
and hypertension.
• Thus, the decision to increase dry-weight has
to be weighed against its potential risks.
2- Increasing dry-weight

57. 3- Fasting during dialysis
• Sherman RA, Torres F, Cody RP. Postprandial blood pressure changes during hemodialysis. Am J Kidney Dis
1988; 12:37–39.

58. 3- Food ingestion
• After a meal:
• 1-Peripheral vascular resistance decreases (20%).
• 2- Blood flow to the splanchnic circulation (35%) and liver
(69 %)increase.
• 3-Baroreceptor responses are impaired after glucose
ingestion.
• Patients with autonomic dysfunction are particularly prone
to hypotension after meals (diabetic patients).
• A prospective controlled trial of 125 hemodialysis
treatments in nine nondiabetic patients.
• Mean BP fell by 14.4 mmHg/h 45 minutes after a meal
consumed between 1.5 and 2 hours after the start of dialysis
versus 2.2 mmHg/h in the control period.
Sherman RA, Torres F, Cody RP.: Am J Kidney Dis 12: 37–39, 1988

59. The mean URR and spKt/V values of
the patients were higher in the
sessions without food ingestion.
The session with food intake showed a faster
decrease in the MAP value after hour 1

60. 4&5)-Sodium and UF profiling

61. • The dialysate sodium concenteartion at the beginning
of the of treatment is hypertonic and during the final
hours of dialysis is progresively reduced , reaching
almost normal levels before the end of dialysis.
• Sodium profiling prevents IDH By:
• 1- An increased ECF sodium level at the time of peak UF
rate improves water shift from ICF to the ECF
compartment with improved venous refill and
prevention of Bezold- jarisch reflex.
• 2- Hypertonic dialysate accelerates urea equiliberation
between ICF and ECF while urea removal is at its peak
during the first hour of dialysis.

62. Ultrafiltration modeling
• Provide higher
ultrafiltration rates early
in the hemodialysis
procedure when the
interstitial space is larger
and plasma refilling is
higher.
• As the treatment
proceeds, the interstitial
space decreases in size,
refilling rates decline,
and ultrafiltration rate is
reduced.

63. 4&5)-Sodium and UF profiling
Disadvantages
• The time-averaged sodium concentration can
result in positive sodium balance .
• Stimulates thirst.
• Larger interdialytic weight gains .
• Increases BP.
• If a higher than mean dialysate sodium
concentration is used early, it must then be
balanced by a lower than mean sodium
dialysate concentration later in the
treatment, which may result in an increase in
IDH during this period.

64. • 24 studies
• 76. 635 patients.
• Effects of different sodium dialysate prescriptions minimum
concentration of 133 mmol/L- a maximum of 145 mmol/L
• Higher DNa+ was significantly associated with greater mortality
only in patients with higher serum sodium concentration.
• There was a trend toward lower mortality for those with lower
predialysis serum sodium concentration when dialysing against
higher DNa+.
• This hypothesis is in agreement with a recent post hoc analysis of
1549 participants of the HEMO study, showing that each 4 mmol/L
increment in baseline pre-dialysis serum sodium concentration
was associated with an HR for all-cause mortality of 0.84.
The current range of 138– 140 mmol/L should be maintained until well-designed
trials will offer new insights.

65. vv

66. 6- Cool temperature dialysis

67. • First described by Maggiore et al. in the 1980s .
Maggiore Q, Proc Eur Dial Transplant Assoc 1981; 18: 597–602
• Body temperature rises during standard dialysis .:
• 1- Heat transfer to the patient from warm
dialysate (especially as many dialysis patients
have low baseline core temperatures),
• 2- Reduced heat loss from the skin due to
vasoconstriction
• 3- Increased thermogenesis from an
inflammatory response to a blood-membrane
reaction.

68. • Sixteen studies (235 patients) examined dialysis
.
• In the control arm of the study, standard
dialysate temperature varied between studies
(38.5C, 37.5C, 37.0C and 36.5C ).
• Cool-dialysis temperature also varied ( 35.5C,
35.0C 34.5C and 34.0C ).
• No studies reported mortality as an outcome
measure.
• universally adequate, most studies did not use
blinding.

69. Outcome measures
Intradialytic hypotension Dialysis adequacy
The rate of IDH with standard dialysis was
7.1 times greater than with cool dialysis
None of these individual studies
reported a difference in adequacy
Kt/V or URR

70. Other outcome measures
• Ventricular contractility:
• A significantly greater increase in the velocity of
circumferential fibre shortening (ventricular contractility
)with cool dialysis.
• Plasma Noradrenaline:
• A significantly greater plasma noradrenaline level with
cool-temperature dialysis .
• Nitric oxide Products:
• A greater fall with cool temperature dialysis.
• Thermal Symptoms:
• Three studies reported increased frequency of thermal
symptoms during the intervention arm.
• 13–19% of patients felt cool in the intervention arm with
a dialysate temperature of 35.0C.

71. 7- Change Dialysate Composition

72. Dialysate composition
Calcium
• Increasing dialysate calcium concentration
improves myocardial contractility (stroke
volume, systolic BP, and postdialysis calcium
concentration )and reduces IDH.
• Limited Data have shown only marginal
benefit on the freqency of IDH episodes with
the use of dialysate Ca > 3.mEq/L.
Gabutti L, Nephrol Dial Transplant 24: 973–981, 2009
Draw BacK:
• Hypercalcemia and decrease Bone Turnover.

73. 8- Convective renal replacement
therapies

74. Convective renal replacement therapies
• A randomized trial that assigned 70 patients to
hemodialysis, 36 to hemofiltration, and 40 to
hemodiafiltration .
• The primary endpoint of this trial was the frequency
of symptomatic IDH compared to the baseline period.
• Among hemodialysis patients, the frequency
increased from 7.1 to 7.9%.
• Hemofiltration, it fell from 9.8 to 8%.
• Hemodiafiltration group it fell from 10.6 to 5.2%.
• The OR for risk reduction in symptomatic IDH for
hemofiltration was 0.69 and for hemodiafiltration it
was 0.6.
• Bolasco P,Ghezzi PM, Serra A, et al. Effects of acetate-free haemodiafiltration (HDF) with endogenous reinfusion
(HFR) on cardiac troponin levels. Nephrol Dial Transplant 2011; 26:258–263.

76. 9-Increased frequency and
duration of dialysis
Short daily hemodialysis

79. 10- Adjusting antihypertensive
medications
• Hold antihypertensive drugs before
hemodialysis based on the rationale that
poorer BP control in the short term is
preferable to IDH, which is especially true for
direct venous (nitrates) and arterial
(hydralazine) dilators.
• One can also administer once daily
antihypertensive medications at bedtime.

80. Pharmacologic measures

81. 8- Midodrine
• Midodrine a prodrug that is rapidly absorbed and
transformed into the active metabolite
desglymidodrine, which is a selective α-1 adrenergic
agonist.
• Administers 2.5–10 mg 15–30 minutes before
dialysis. A second smaller dose can be given halfway
through the treatment.
• It has high bioavailability, with peak levels occurring
at 60 minutes, and it is removed by hemodialysis
(half-life is 3.0 hours on hemodialysis); therefore,
the drug effect does not persist long in the
postdialytic period.
Prakash S, et al.: Midodrine appears to be safe and effective for dialysis-induced hypotension: A
systematic review. Nephrol Dial Transplant 19: 2553–2558, 2004.

82. • Nine studies
• 117 patients.
• There was also a decrease in
symptoms of IDH with midodrine
and very few adverse side effects.
• Limitation is the quality of the
studies.
• two of the studies were crossover in
design but the remainder were pre-
and post-intervention.
• There were no published
randomized controlled parallel
group trials .
• The number of patients in each
study was small.

83. Used Cautiously
• CHF
• Negative intropes (beta Blockers)
• Alpha adrenergic agents (ephrdrine,
…Aggrevate supine hypertension)
• Antagonize action of alpha adrenergic blockers
(terazocin, Prazocin..)….. Urinary retention

84. Sertaline
• SSRI
• Neurocardiogenic syncope,
Idiopathic orthostatic hyotension,
IDH
• SE; Inomnia, Dizzness, fatigue,
Somnolence and Headache.

86. • Laughter can provide (spontaneous or simulated).
• 1- Improving mood
• 2- Reducing depression
• 3- Improving life satisfaction nd quality of life
• Laughter Yoga (LY), developed in India in 1995 (clapping, arm and leg movement, deep breathing
exercises, gentle neck and shoulder stretches as well as facilitated laugh and smile exercises ) .
• Takes only 30 to 45 min, and is appropriate for group settings Methods.
• Design : 12 weeks
• The number of IDH episodes in the four weeks prior to the LY intervention (pre), four weeks of the
LY (during), and four weeks after the (post) was compiled retrospectively.
• Intradialytic hypotensive (IDH) episodes
• There were 19 IDH episodes recorded in the month preceding the LY, 19 IDH episodes recorded
during, and four recorded post LY intervention. Based on these data, the odds of IDH decreased by
80 % (OR = 0.20, CI = 0.07 – .61) which was statistically significant (χ21 = 9.76, p = .002).
• The reasons for this difference are unclear but it is unlikely that a change of this magnitude would
be related to the intervention alone.

87. How to increase BP?

88. TEMS & PCMs during dialysis show
significant results in raising BP

89. • Dietary counseling on limiting salt intake,
which resulted in a reduction of his
interdialytic weight gain from 4 to 2.5 kg.
Over the subsequent 2 months, there
were no additional episodes of IDH. His
predialysis BP has been stable around
130/60 mmHg.
Clin J Am Soc Nephrol. 2014 Apr 7; 9(4): 798–803.

91. Conclusion
• IDH is and will continue to remain a management
challenge for nephrologists given the cyclical nature of
expansion and contraction of the extracellular fluid
volume with three times a week hemodialysis and
difficulties in restricting sodium intake.
• Manipulations of the hemodialysis prescription and
pharmacologic agents can help reduce the frequency of
IDH.
• Salt restriction in an attempt to limit interdialytic
weight gain, frequently use cool dialysate, administer
midodrine in those patients who cannot tolerate cool
dialysate when appropriate, prohibit food ingestion
during the dialysis procedure, and use ultrafiltration
modeling.

93. • Within the brain, MRI have shown pathological findings
including the presence of leukoariaiosis, “a nonspecific
change in the brain white matter caused by loss of axons and
myelin because of ischemic injury” (McIntyre, 2010) which is
thought to increase vascular ageing.
• “This form of subcortical injury occurs precisely ... where
episodic intradialytic reduced perfusion would be expected
to have its maximal effect” (McIntyre, 2010).

95. Bradycardiac type
(Bezold-jarisch reflex)

96. Tachycardiac
hypotension

100. Dysbiosis
• An imbalanced intestinal microbial community
with quantitative and qualitative alterations in
the composition and metabolic activities of the
gut microbiota.
• The main contributing factors :
1- Slow intestinal transit time .
 2-Impaired protein assimilation .
3- Decreased consumption of dietary fiber.
 4-Iron therapy .
5- Frequent use of antibiotics.

101. Schematic representation of the association between uremia, dysbiotic gut microbiome, gut-derived uremic toxins, and
clinical manifestations of these uremic toxins.

102. Measurement of Body Fluid Volumes
• A variety of methods are used to
determine body fluid volumes.
• Methods differ with respect to
underlying principles and the
fluid compartment of interest .
• Tracer dilution and
bioimpedance techniques can
estimate ECV, ICV, and total body
water (TBW, TBW = ECV+ ICV),
• Monitoring of relative blood
volume changes during HD,
inferior vena cava diameter
(IVCD) measurements and
biochemical markers (such as
atrial natriuretic peptide, brain
natriuretic peptide [BNP])
provide information about the
intravascular filling state.
IF, interstitial fluid;
ECV, extracellular fluid;
PV, plasma volume;
RBCV, red blood cell volume;
ICV, intracellular fluid;
BIA, single or multifrequency
bioimpedance analysis
; IF pressure, interstitial fluid
pressure;
RBV, relative blood volume;
IVCD, inferior vena cava
diameter..

106. Conclusion
• Biochemical markers and the IVCD method do not directly
reflect ECV, which limits their clinical use.
• Relative blood volume monitoring may be useful to define
individual tolerance levels for fluid removal, but it cannot
provide information about ECV status.
• Currently, methods of multifrequency bioimpedance
spectroscopy appear to be the preferred method to
determine the ECV status in HD patients within a clinical
setting.
• Combining BIS and RBV monitoring may help deliver HDwith
both adequate fluid removal using a dry weight goal defined
by BIS, and safe margins of ultrafiltration rate to prevent
intradialytic hypotensive episodes.

107. • IDH is an important cause of morbidity among
dialysis patients.
• Recently, the generation of endotoxins from an
ischemic gut is proposed as a novel pathway that
may cause IDH.
• Automatic biofeedback-controlled dialysis may
improve IDH in part by improvement in myocardial
stunning and preservation of cardiac function.
• However, the effects of automatic biofeedback
dialysis are inconsistent between studies and
sample sizes are small.

108. • Cool temperature dialysate causes
vasoconstriction, activates the sympathetic
nervous system, preserves central blood
volume, and mitigates IDH.
• Increasing the treatment time to at least 4h
three times a week and limiting dialysate and
dietary sodium intake are effective ways to
reduce IDH.
• Ultrafiltration profiling needs further work, but
it appears that removing more fluid during the
first hour of dialysis and reducing the rate later
on may also reduce IDH.

109. Conclusion
• Reducing dialysate temperatureis an effective
intervention to reduce the rate of IDH.
• Overall, there was a trend to an increased
frequency of cold symptoms with cool dialysis
• Reducing the temperature of the dialysate is an
effective intervention to reduce the frequency of
IDH.
• Cool dialysis does not adversely affect dialysis
adequacy

114. • We found that pedal edema in HD patients was
associated with common cardiovascular risk
factors such as older age, overweight or obesity,
and left ventricular hypertrophy.
• Edema was not correlated to NT-proBNP, IVC
diameter, collapse index, ejection fraction, right
atrial pressure, left atrial diameter, or changes in
RBV.
• This suggests that edema may not be a marker
of intravascular volume in stable long-term HD
patients.