The Approach to Complications During Hemodialysis

THE APPROACH TO COMPLICATIONS DURING

HEMODIALYSISHazel Daphne Niñalga

Philippine Society of Nephrology

National Kidney and Transplant InstituteJuly 15 , 2011

1

Acute complications during Acute complications during hemodialysishemodialysis

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Acute complications during hemodialysisAcute complications during hemodialysis

Common complications INTRODUCTION — Acute complications commonly occur during

routine hemodialysis treatments. They include the following:• Hypotension — 25 to 55 percent of treatments• Cramps — 5 to 20 percent• Nausea and vomiting — 5 to 15 percent• Headache — 5 percent• Chest pain — 2 to 5 percent• Back pain — 2 to 5 percent• Itching — 5 percent• Fever and chills — Less than 1 percent

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HYPOTENSION• The incidence of a symptomatic hypotension during (or

immediately following) dialysis ranges from 15 to 50 percent of dialysis sessions

• There are two clinical patterns of dialysis-associated hypotension:

1.1. Episodic hypotensionEpisodic hypotension, which occurs during the latter stages of dialysis and associated with vomiting, muscle cramps, and other vagal symptoms (such as yawning).

2.2. Chronic persistent hypotensionChronic persistent hypotension, , which may occur in long-term patients in whom predialysis systolic blood pressures of less than 100 mmHg ,are frequently observed.

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ETIOLOGYETIOLOGY Common causesCommon causesA. Volume related ( (excessive or rapid decreases in blood

volume)1. A rapid reduction in plasma osmolality, which causes

extracellular water to move into the cells.2. Large weight gain3. Rapid fluid removal in an attempt to attain "dry weight“

(Short dialysis )4. Inaccurate determination of true "dry weight" .5. Use of a lower sodium concentration in the dialysate.

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Water movement during standard hemodialysis ۲۰۲۳/۰۴/۰۸ ۰۰:۳۱6


B. Inadequate vasoconstriction:

1. High dialysis solution temprature (> 36°c)2. Autonomic neuropathy (50 percent of patients on HD)a. Defect in the baroreceptor/afferent side b. Downregulation of alpha-adrenergic receptors 3. Use of acetate rather than bicarbonate as a dialysate buffer.4. Intake of antihypertensive medications that can impair

cardiovascular stability. 5. Sudden release of adenosine during organ ischemia. [eg. Anemia

(HCT< 20 - 25%)].6. Ingestion of a meal immediately before or during dialysis

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Therapeutic implicationsa. Lower dialysis solution temperatureb. Avoid intradialytic food ingestion in

hypotension-prone patientsc. Minimize tissue ischemia during dialysisd. Midodrine in refractory cases:• A dose of 10 mg orally one-half to 2 hours

before a dialysis session is typical• Active cardiac ischemia is a contraindication

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e. Consider a trial of sertraline • 50- 100mg/day• 4 to 6 weeks of therapy with the selective

serotonin reuptake inhibitor sertraline reduces the frequency of intradialytic hypotension.

• The drug improves autonomic function

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C.Cardiac factors:1. Diastolic dysfunction (stiff concentric hypertrophy heart)• the effects of hypertension• coronary artery disease• uremia itself2. Impairment of cardiac compensatory mechanisms (Heart

rate and contractility)• Arrhythmia (atrial fibrilation), which are volume-

unresponsive causes of hypotension.• Ischemia

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• Therapeutic implications:1.A dialysis solution calcium concentration of 1.75

mM (3.5 mEq/l)2.Dialysis solution magnesium levels (a higher or a

lower level should be used is controversial ).

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Uncommon causes:Uncommon causes:I. Pericardial tamponade , that is volume-unresponsive

cause of hypotension.II. Myocardial infarctionIII.Valvular disordersIV.Occult hemorrhageV.HemolysisVI.SepticemiaVII.Dialyzer reaction, which may cause wheezing and

dyspnea as well as hypotension VIII.Air embolism

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DIAGNOSISDIAGNOSIS• Most Patients with hypotension complaint of feeling dizzy, light-

headedness, nausea, vomiting, and dyspnea.• Some patients suffer muscle crampsmuscle cramps, , lack of alertnesslack of alertness, , darkening darkening

of vision.of vision.• In some patients, there are no symptoms until the BP falls to very

low and dangerous level.• For this reason, BP must be monitored on a regular basis

throughout HD session.TREATMENTTREATMENT • The acute management acute management of low blood pressure associated with

hemodialysis:• Ultrafiltration should either be stopped or the rate decreased.• The patient should be placed in the Trendelenburg position.

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Trendelenburg position

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III. The blood flow rate should be reduced, if hypotension is severe or the patient is not responding to other treatment measures.

IV. Intravascular volume may be replaced with mannitol or saline [currently used an intravenous bolus of saline (100 ml or more) as first-line therapy for hypotension].

• The prompt recognition of life-threatening causes of low blood pressure is essential.

• Particular concerns should include occult sepsis, previously unrecognized cardiac and/or pericardial disease, and gastrointestinal bleeding.

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• Patients with chronic, debilitating hemodialysis hypotension due to the inability to adequately respond to rapid changes in blood volume may be more likely to tolerate the gradual volume changes associated with peritoneal dialysis.

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PREVENTIONPREVENTION• Accurate setting of the "dry weight“:Accurate setting of the "dry weight“: At present, the determination of dry weight is largely determined empirically by trial and error.

The dry weight is set at the weight below which unacceptable symptoms, such as cramping, nausea, and vomiting, or hypotension occur.

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Other modalities to more objectively estimate dry weight :

I. Plasma atrial natriuretic peptide (ANP)levelsII. A noninvasive assessment of conductivity is an

accurate estimate of the extracellular volume and can detect underhydration after dialysis (bioimpedance measurements).

III. Ultrasound assessment of the inferior vena cavaIV.IV.Steady, constant ultrafiltrationSteady, constant ultrafiltration V. Newer dialysis machines remove volume steadily

and evenly over the course of the dialysis session

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• Avoid large interdialytic weight gain Avoid large interdialytic weight gain (IDWG) or short treatment(IDWG) or short treatment

To avoid for rapid UF rate1. patients should be limit IDWG to <1 kg per limit IDWG to <1 kg per

dayday,( by limiting of salt intake).2.An increase in treatment time increase in treatment time is also an effective way of decreasing UF rate and frequency IDH.

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• Increased dialysate sodium concentration Increased dialysate sodium concentration and sodium modelingand sodium modeling

The following three sodium dialysate concentration strategies:

I. A constant sodium concentration of 140 meq/LII.Sodium modeling: a) LinearLinear sodium ramping (155 to 140 meq/L) b) StepwiseStepwise sodium ramping (155 meq/L for three

hours and 140 meq/L for one hour)

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The use of a higher dialysate sodium concentration (140 meq/L) has been among the most efficacious and best tolerated therapies for episodic hypotension

limitations of dialysate sodium modeling:I. The lack of correlation between blood volume

degree and onset of hypotensionII. Significant individual and interdialysis

variations in sodium levelsIII. Thirst and weight gain with postdialysis

hypertension ۲۰۲۳/۰۴/۰۸ ۰۰:۳۱21


• Combination sodium modeling and Combination sodium modeling and ultrafiltrationultrafiltration

Ultrafiltration profiling Ultrafiltration profiling is characterized by the ultrafiltration rate being intermittently stopped or decreased gradually, thereby resulting in plasma refilling.

The combination of ultrafiltration and sodium The combination of ultrafiltration and sodium profiling profiling can further enhance plasma refilling; in turn, this can result in greater stability during hemodialysis.

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• Sequential ultrafiltration and Sequential ultrafiltration and isovolemic dialysisisovolemic dialysis

A similar goal of maintenance of the plasma osmolality can be attained by initial initial ultrafiltration aloneultrafiltration alone (without dialysis) followed by isovolemic dialysisisovolemic dialysis in which little or no further fluid removal occurs due to reduced transmembrane pressures.

A large volume of fluid to be removed without inducing hemodynamic instability.

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Water movement during isolated ultrafiltrationWater movement during isolated ultrafiltration۲۰۲۳/۰۴/۰۸ ۰۰:۳۱24


• Bicarbonate dialysate bufferBicarbonate dialysate buffer Bicarbonate is now widely available and adaptable to all new dialysis machines.

The blood pressure is generally better maintained with bicarbonate.

Acetate accumulation in the blood has vasodilator activity that can promote the development of hypotension.

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• Temperature controlTemperature controlThe use of low dialysate temperature can improve hemodynamic stability by improving cardiovascular contractility and increasing venous tone.

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• Improvement in cardiovascular Improvement in cardiovascular performanceperformance

The frequency of dialysis-associated hemodynamic instability is greatly increased in patients with a prior history of congestive heart failure, cardiomegaly, or ischemic heart disease.

Cardiovascular performance can be enhanced in many dialysis patients in the following ways:

I. Increasing the dialysate dialysate calcium concentration concentration.II. Using cool temperature hemodialysis, which can also

increase vascular resistance.III. Correction of anemia with erythropoietin.

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• MidodrineMidodrine Among patients with autonomic

neuropathy and perhaps others with severe hemodialysis hypotension not responsive to the above measures, the selective alpha-1 adrenergic agonist selective alpha-1 adrenergic agonist midodrinemidodrine may be effective and well tolerated

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• CarnitineCarnitine Carnitine supplementation has reduced the incidence of hypotensive episodes and muscle cramps.• Avoidance of foodAvoidance of foodFood ingestion during dialysis leads to a significant decline in systemic vascular resistance that can contribute to a fall in blood pressure.

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• Adenosine releaseAdenosine release Adenosine is an endogenous vasodilator that has been related to hypotensive episodes in a subset of patients on hemodialysis.

This response can be blunted in some patients by the administration of caffeine, which may act as an adenosine receptor antagonist in this setting.

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• Vasopressin infusionVasopressin infusionIt has been observed that vasopressin release is not increased in hemodialysis patients undergoing volume removal.

Constant infusion Constant infusion of a non-pressor dose of vasopressin has been significantly associated with a decreased incidence of symptomatic hypotensive episodes and increased fluid removal.

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• Comparative efficacyComparative efficacyIn general, the best tolerated and most

effective strategy is sodium modeling.High sodium and cool temperature dialysis were also effective.

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Muscle cramps• Etiology:Etiology: The pathogenesispathogenesis of muscle cramps during dialysis is unknownunknown.• Changes in plasma osmolality and/or extracellular fluid

volume have been implicated The four most important predisposing factors are :• Hypotension • Hypovolemia (patient below dry weight)• High UF rate (large weight gain)• Use of low-sodium dialysis solution (Hyponatremia)

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Muscle cramps most commonly occur in association with hypotension.

Cramping is also more common during the first month of dialysis than in subsequent periods.

• PathophysiologyThese factors all tend to favor vasoconstriction resulting in muscle hypoperfusion leading to secondary impairment of muscle relaxation.

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Hypomagnesemia and hypocalcemia may cause treatment-resistant muscle treatment-resistant muscle cramping cramping during dialysis.

Predialysis hypokalemia will be exacerbated by the usual level of dialysis solution potassium (2mM) and may precipitate cramping as well.

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Other factors that related with hemodialysis-associated cramps:

Carnitine deficiency Elevated serum leptin levels Low PTH values and high serum creatine

phosphokinase concentrations

The origin of a cramp is neural, not muscular.

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http://www.uptodate.com/contents/l-carnitine-drug-information?source=see_link

• CLINICAL FEATURESMost commonly involve the muscles of the

lower extremityCramps occur more often in older,

nondiabetic, anxious patients.

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• ManagementManagement Concomitantly Hypotension & muscle cramps⇒ 1. Treatment with 0.9% saline2. Ultrafiltration be stopped or the rate decreased3. Trendelenburg position4. Blood flow rate should be reduced5. Hypertonic solutions ( saline, glucose 50%, mannitol 12.5 to

37.5 g/dialysis).6. Forced stretching of the muscle involved (eg. Ankle flexion

for calf cramping).7. Nifedipine(10 mg)8. Massage 9. moist heat

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• PreventionPreventionI. Prevention of hypotensive episodesII. Raisening of dialysate-sodium levels to just below the

threshold for induction of postdialysis thirst.III.Avoiding low predialysis levels of mg2+, Ca2+, K+.IV.Quinine sulfate . Quinine sulfate before dialysis 250-325 mg

(Not FDA approved).V. Carnitine supplementation in dialysis patients.VI.Vitamin E(400 IU) VII.Oxazepam ( 5-10 mg, given 2 hrs prior to dialysis).VIII.Prazosin.IX.Stretching exercises of affected muscle groups.X. Nifedipine, phenytoin, creatine monohydrate,

carbamazepine, amitriptyline, and gabapentin. ۲۰۲۳/۰۴/۰۸ ۰۰:۳۱40

http://www.uptodate.com/contents/nifedipine-drug-information?source=see_link

http://www.uptodate.com/contents/phenytoin-drug-information?source=see_link

http://www.uptodate.com/contents/carbamazepine-drug-information?source=see_link

http://www.uptodate.com/contents/amitriptyline-drug-information?source=see_link

http://www.uptodate.com/contents/gabapentin-drug-information?source=see_link


HEADACHE, NAUSEA, AND VOMITINGHEADACHE, NAUSEA, AND VOMITING• Longer treatment times • combined with large degree of urea removal

and/or ultrafiltration significantly enhance the enhance the incidence incidence of headache, nausea, and vomiting during dialysis.

• A variant A variant of the dialysis disequilibrium syndrome may underlie these symptoms in many patients.

• Dialysis disequilibrium is thought to be due to water movement into the brain as a result of a reverse osmotic shift induced by urea removal.

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HEADACHE:HEADACHE:1. Etiology• largely unknown.• A subtle manifestation of the disequilibrium syndrome• Caffeine withdrawal (coffee drinkers)• Metabolic disturbances (eg, hypoglycemia,

hypernatremia, hyponatremia), uremia, subdural hematoma, and medication-induced headaches should be considered in patients with recurrent dialysis-associated headaches.

• Magnesium deficiency • psychological factors

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2. Prevention:1.In this setting, initially altering the dialysis prescription in favor of less intensive and more frequent treatments may avoid these complications.2.Decreasing dialysis solution sodium 3.A cup of strong coffee 4.A cautious trial of magnesium supplementation

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3. Management•Acetaminophen•A cup of strong coffee

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• Nausea or vomiting occurs in up to 10% of routine dialysis treatment.

• The causes of nausea and vomiting:1. Hypotension(most episodes)2. Dialysis Disequilibrium Syndrome(DDS)3. type A and type B varieties of dialyzer reactions4. Exacerbated Gastroparesis5. Contaminated or incorrectly formulated dialysis

solution(high sodium, calcium).6. Upper respiratory infection7. Narcotic usage8. Hypercalcemia

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• Management:1. To treat hypotension2. Persistent nausea and vomiting unrelated to

hemodynamics may benefit from metoclopramide.

• Prevention: 1. Avoidance of hypotension during dialysis. 2.single predialysis metoclopramide(5-10mg).

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CHEST PAIN CHEST PAIN • Often associated with some back pain, occurs in 1%-4%

of dialysis treatments• Chest pain that occurs while a patient is being dialyzed may be

associated with:I. HypotensionII. Dialysis disequilibrium syndromeIII. AnginaIV. HemolysisV. PericarditisVI. Air embolism (rarely) VII.pulmonary embolism (extremely uncommon )

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I.I. AnginaAngina Angina should always be considered as the

underlying cause of chest discomfort in the patient undergoing dialysis.

If clinically indicated, ECG and cardiac enzyme evaluation should therefore be performed.

If dialysis is continued, the administration of oxygen and aspirin , reduction of the desired ultrafiltration, and/or blood pump speed and administration of nitrates or morphine should be considered on an individual basis.

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http://www.uptodate.com/contents/aspirin-drug-information?source=see_link


II.II. HemolysisHemolysis

Hemolysis may present as chest pain, chest tightness, or back pain.

If hemolysis is not recognized early, severe hyperkalemia may ensue and lead to death.

These findings highly suggestive of substantial hemolysis include:

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These findings highly suggestive of substantial hemolysis include:

A.A port wine appearance of the blood in the venous line.B. Complaints of chest pain, shortness of breath, and/ or

back painC. A falling hematocrit

D.A pink color of the plasma in centrifuged specimens.

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The etiology of hemolysis in hemodialysis patients includs:

A.Problems with the dialysis solution:B.OverheatingC.HypotonicityD.Contamination with formaldehyde,

bleach(Sodium hypochlorite) , chloramine, or nitrates from the water supplywater supply, and copper from copper tubing or piping.copper tubing or piping.

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B. Red blood cell trauma due to:I. Improperly functioning roller clamps

on dialysis machinesII. Kinking of the blood linesIII. Poorly constructed blood tubing

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Treatment:I. To stop dialysis immediatelyII.Clamp the blood lines (do not return the

blood to avoid increasing the risk of hyperkalemia)

III.Prepare to treat hyperkalemia and the potentially severe anemia

IV.Hospitalization for observation ( for life-threatening hyperkalemia

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III.III. Air embolismAir embolism It can lead to death unless quickly

detected and treated Air embolism is rare in hemodialysis

patients, in part because of the presence of air detectors in hemodialysis machines.

Diagnosis: Foam in the venous blood line should make one suspect that air is entering the dialysis system.

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Disconnection of connecting caps and/or blood lines can also lead to air embolism in patients being dialyzed with central venous catheters.

In the seated patient, air tends to migrate into the cerebral venous system without entering the heart, as a result, this patient may lose consciousness and seizure.

The recumbent patient may initially develop dyspnea, cough, and perhaps chest tightness.

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Treatment:I. Clamping the venous lineII. Stopping the blood pumpIII. The patient should be positioned

on the left side in a supine position with the chest and head tilted downward.

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ItchingItching• Itching appearing only during the

treatment, especially if accompanied by other minor allergic symptoms, may be a manifestation of low-grade hypersensitivity to dialyzer or blood circuit component.

• Standard symptomatic treatment using antihistamines is useful.

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Fever and chillsFever and chills• The causes of fever and chills during HD including:I. Bacteremia: Bacteremia related to the access site infection access site infection (venous

access, AV fistulas and grafts). Bacteremia may result from contamination of hemodilysis contamination of hemodilysis

machines machines ( inadequate disinfection of water treatment , distribution systems or reprocessed dialyzers).

II. Pyrogen reaction: Low-grade fever during hemodialysis may be related to

pyrogens present in the dialysis solution rather to actual infection.

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Charecteristics of fever:Charecteristics of fever:a) Patients are afebrile prior to dialysis but become

febrile during dialysis.b) Fever resolves spontaneously after cessation of

dialysis.c) There is one exception to the rule : fever and

chills that occur shortly after catheter manipulation (eg, commencement or cessation of dialysis) suggests catheter associated bacteremia.

Blood cultures shoulds always be obtained in any febrile HD patients.

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Less common but serious complications

• These include:I. Disequilibrium syndromeII. Hypersensitivity reactionsIII. ArrhythmiaIV. Cardiac tamponadeV. Intracranial bleedingVI. SeizuresVII. HemolysisVIII. Air embolism

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Dialysis disequilibrium syndrome

A.A. INTRODUCTIONINTRODUCTION • The dialysis disequilibrium syndrome (DDS)

is a central nervous system disorder described in dialysis patients.

• It is characterized by neurologic symptoms of varying severity that are thought to be due primarily to cerebral edema.

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• New patients just being started on hemodialysis are at greatest risk, particularly if the BUN is markedly elevated (above 175 mg/dL or 60 mmol/L).

B. PATHOGENESISB. PATHOGENESIS• The cause of the disequilibrium syndrome is controversial• The symptoms of DDS are caused by water movement into

the brain, leading to cerebral edema.• Two theories Two theories have been proposed to explain why this occurs:1. A reverse osmotic shift induced by rapidly urea removal (the

plasma becomes hypotonic with respect to the brain cells). 2. Acute changes in the PH of the cerebrospinal fluid and a fall

in cerebral intracellular pH.

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I. Reverse osmotic shift The reduction in BUN lowers the plasma osmolality,

thereby creating a transient osmotic gradient that promotes water movement into the cells.

In the brain, this water shift produces cerebral edema and a variable degree of acute neurologic dysfunction.

Urea is generally considered an "ineffective" osmole, but there is insufficient time for urea equilibration when hemodialysis rapidly reduces the BUN; as a result, urea transiently acts as an effective osmole, promoting water movement into the brain.

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II. Intracerebral acidosis and idiogenic osmoles Some investigators have proposed that a

decrease in cerebral intracellular pH, occurring via an uncertain mechanism, is of primary importance .

Both displacement of bound sodium and potassium by the excess hydrogen ions and enhanced production of organic acids can increase intracellular osmolality and promote water movement into the brain

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C. CLINICAL MANIFESTATIONS• The classic DDS refers to acute symptoms

developing during or immediately after hemodialysis.

• Mild disequilibrium:Mild disequilibrium:C. Early findings include headache, nausea,

disorientation, restlessness, blurred vision, and asterixis.

• Severe disequilibrium:Severe disequilibrium: More severely affected patients progress to

confusion, seizures, coma, and even death.۲۰۲۳/۰۴/۰۸ ۰۰:۳۱65


• It is now recognized, however, that many milder signs and symptoms associated with dialysis — such as muscle cramps, anorexia, and dizziness developing near the end of a dialysis treatment — are also part of this syndrome

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D. DIAGNOSIS AND DIFFERENTIAL DIAGNOSIS• The development of the above symptoms during dialysis

is strongly suggestive of DDS.• Differential diagnosis of DDS include:1. uremia itself2. subdural hematoma3. cerebral infarction4. intracerebral hemorrhage5. Meningitis6. metabolic disturbances (hyponatremia, hypoglycemia)7. drug-induced encephalopathy

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E. PREVENTION• The initial dialyses should be

gentle, but repeated frequently.• The aim is a gradual reduction in

BUN, which will be protective but may not prevent mild symptoms such as headache and malaise.

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• Slow urea removal methodsSlow urea removal methodsI Initial heamodialysis prescription, arranged

with:1. Cession time of two hours.2. Relatively low blood flow rate (150 to 250

mL/min)3. A small surface area dialyzer (0.9 to 1.2 m2)4. Concurrent rather than countercurrent blood

and dialysate flow.۲۰۲۳/۰۴/۰۸ ۰۰:۳۱69


1. This regimen is repeated daily for three or four days.

2. If the patient shows no signs of DDS, then:a) The blood flow rate can be increased by 50

mL/min per treatment (up to 300 to 400 mL/min)

b) The duration of dialysis can be increased in 30 minute increments (up to four or more hours, as necessary for adequate solute removal). ۲۰۲۳/۰۴/۰۸ ۰۰:۳۱70


II. Patients who also have marked fluid overload can be treated with ultrafiltration (which removes less urea per unit time) followed by a short period of hemodialysis.

III. The patient can be started on peritoneal dialysis in which the low rate of peritoneal blood flow results in a urea clearance per unit time that is much lower than that with hemodialysis.

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IV. Some physicians recommend:1. Prophylactic phenytoinphenytoin (1000 mg loading dose

followed by 300 mg/day until uremia is controlled)

2. The administration of 12.5 g of hypertonic hypertonic mannitolmannitol intravenously every hour of dialysis in high-risk patients with marked azotemia (BUN above 150 to 200 mg/dL [54 to 71 mmol/L]) or an underlying alteration in mental status.

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Acute Acute complications during during hemodialysishemodialysis

F. Management1.1. Mild disequilibrium Mild disequilibrium The management of mild nonspecific

disequilibrium symptoms, such as nausea, vomiting, restlessness, and/or headache, is symptomatic

In the acutely uremic patient with such symptoms who is undergoing dialysis, the blood flow rate should be slowed and consideration should be given to stopping the dialysis session earlier than planned.

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2.2. Severe disequilibriumSevere disequilibrium Dialysis is stopped in the patient with

seizures, coma, and/or obtundation. Patency of the airway should also be

ensured The differential diagnosis of severe DDS

should be considered. Severe DDS with seizures can be reversed

more rapidly by raising the plasma osmolality with either 5 mL of 23 percent saline or 12.5 g of hypertonic mannitol.

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Management is supportive in the patient with severe DDS and coma, that including:

a) The airway should be controlled.b) The patient ventilated if necessary.c) Intravenous mannitol may be of benefit. In this setting, improvement should occur

within 24 hours .

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ARRHYTHMIASARRHYTHMIAS• Ventricular arrhythmias are common during

dialysis and between treatments.• Supraventricular arrhythmias are also common.• Risk factors for arrhythmias and sudden death

in dialysis patients include:I. coronary artery diseaseII. advanced ageIII. myocardial dysfunctionIV. left ventricular hypertrophy ۲۰۲۳/۰۴/۰۸ ۰۰:۳۱76


• During hemodialysis, the incidence of arrhythmias may be enhanced because of:

I. Rapid fluctuations in hemodynamics and electrolyte concentrations

II. The induction of hypoxemia in patients with a high incidence of myocardial disease

• The treatment of arrhythmias, is similar to their treatment in the nondialysis patient.

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THE END

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Documents

The Approach to Complications During Hemodialysis