complications of hemodialysis and their management
They can be broadly divided into two categories:
a) Complications during a hemodialysis session.
b) Complications of long-term hemodialysis.
This section will deal only with problems occurring during a dialysis session. They can be classified into common problems and uncommon but serious complications.
Complications that occur during a hemodialysis session.
– Muscle cramps
– Nausea and vomiting
– Chest and back pain
– Febrile reactions
– First-use syndromes
– Cardiopulmonary arrest during dialysis
Uncommon but serious complications
– Disequilibrium syndrome
– Dialyzer reactions
– Cardiac tamporade
– Intracranial bleeding
– Air embolism
– Dialysis-associated neuropenia & complement activation
Common clinical problems during a HD session
The common complications that occur during a hemodialysis sessions are:
1) Hypotension (20-30% of dialysis),
2) Muscle cramps (5-20%),
3) Nausea and vomiting (5-15%),
4) Headache (5%),
5) Chest pain (2-5%), and back pain (2-5%),
6) Febrile reactions
7) Itching (5%),
Fever and chills (<1%),
9) Cardiopulmonary arrest.
The cause of hypotension, which can be classified into common and uncommon.
1.Related to excessive decreases in blood volume
a. Fluctuations in the ultra filtration rate
b. High ultra filtration rate (to treat a large interdialysis weight gain)
c.Target dry weight set too low
d. dialysis solution sodium level too low
2. Related to lack of vasoconstriction
a. Acetate-containing dialysis solution
b. Food ingestion (splanchnic vasodilatation)
c. Tissue ischemia (adenosine-mediated, aggravated by low hematocrit)
d. Autonomic neuropathy (e.g., diabetic)
e. Dialysis solution that is relatively too warm
f. Antihypertensive medications
3. Related to cardiac factors
a. Cardiac output unusually dependant on cardiac filling: Diastolic dysfunction due to left ventricular hypertrophy, schemic heart disease, or other conditions
b. Failure to increase cardiac rate
(I) Ingestion of beta-blockers
(ii) Uremic autonomic neuropathy
c. Inability to increase cardiac output for other reasons:
Poor myocardial contractility due to age, hypertension, atherosclerosis, myocardial calcification, valve disease, amyloidosis, etc.
Detection of Hypotension:
Most patients will complain of feeling dizzy, light-headed, or nauseated when hypotension occurs. Some experience muscle cramps. Other may experience no symptoms whatsoever until the blood pressure falls to extremely low (and dangerous) levels. Thus, blood pressure must be monitored on a regular basis in all patients throughout the hemodialysis session.
Management of hypotension
a) Fluid administration:
Management of the acute hypotensive episode is straightforward. The patient should be placed in the trendelenburg position (if respiratory status allows this). A bolus of 0.9% saline (100 ml or more, as necessary) should be rapidly administered through the venous blood line. The ultra filtration rate should be reduced to as near zero as possible. Ultra filtration can be resumed (at a slower rate, initially) once vital signs have stabilized. As an alternative to 0.9% saline, hypertonic saline, glucose, mannitol, or albumin solutions can be used to treat the hypotensive episode. Unless cramps are also present, use of hypertonic solutions appears to offer no benefit over 0.9% saline. Nasal oxygen administration may also be of benefit by virtue of helping to improve or maintain myocardial performance.
b) Slowing the blood flow rate:
In the past, part of initial therapy for dialysis hypotension was to slow the blood flow rate, a practice developed at a time when plate dialyzers and acetate dialysis solution were being used. There are four potential reasons to lower the blood flow rate to treat hypotension:
I) when plate dialyzers are used, reduction of the blood flow rate reduces pressure in the blood compartment of the dialyzer. The plates come closer together, reducing the total volume of the extracorporeal circuit.
ii) When acetate dialysis solution is used, reduction of blood flow rate reduces transfer of acetate to the patient.
iii) When an ultra filtration controller is not used, slowing the blood flow rate makes it easier to limit the amount of ultra filtration.
iv) At very rapid blood flow rates and at a low cardiac output, there may be a “steal” effect by the extracorporeal circuit, with diversion of blood from systemic tissue beds.
Prevention of hypotension:
A useful strategy to help prevent hypotension during dialysis is:
1-Use a dialysis machine with an ultra filtration controller whenever possible.
2-Counsel patient to limit weight gain to < 1 kg/day.
3-Do not ultra filter a patient to below his or her dry weight.
4-Keep dialysis solution sodium level at or above the plasma level.
5-Give daily dose of antihypertensive medications after, not before, dialysis.
6-Use bicarbonate-containing dialysis solution when high blood flow rate or high-efficiency dialyzers are used.
7-In selected patients, try lowering the dialysis solution temperature to 34-36°C.
8-Ensure that hematocrit is > 25-30% pre-dialysis.
9-Do not give food or glucose orally during dialysis to hypotensive-prone patients.
The pathogenesis of muscle cramps during dialysis is unknown. The three most important predisposing factors are hypotension, the patient being below dry weight, and/or use of sodium-poor dialysis solution.
When hypotension and muscle cramps occur concomitantly, the hypotension may respond to treatment with 0.9% saline, but the muscle cramps may persist. Muscle-bed blood vessels can be dilated by hypertonic solutions. Perhaps for this reasons, administration of hypertonic saline or glucose is very effective in the acute management of muscle cramps.
Prevention of cramps:
Prevention of hypotensive episodes will eliminate the majority of episodes of cramping. Increasing the dialysis solution sodium level to 145 mmol/liter or higher may also be of benefit. Strategies of decreasing sodium dialysis sometimes can be useful to treat patients with refectory intradialytic cramps. Start out with a sodium level of 150-155 and program in a linear fashion, decrees to 135-140 mmol/liter by the end of treatment. Carnitine supplementation of dialysis patients might result in fewer muscle cramps during dialysis. Other strategies are to administer orally quinine sulfate 260 mg, or oxazepam 5-10 mg, 2 hours prior to dialysis. A program of stretching exercises targeted at the affected muscle groups may also be useful.
Nausea and vomiting
Nausea or vomiting occurs in up to 10% of routine dialysis treatments. The etiology is multifactorial. Most episodes in stable patients are probably related to hypotension. Nausea or vomiting can also be early manifestation of the so-called disequilibrium syndrome.
The first step is to treat any associated hypotension. If nausea persists, an antiemtic can be administered.
Avoidance of hypotension during dialysis is of prime importance. In some patients, reduction of the blood flow rate by 30% during the initial hour of dialysis may be of benefit. A change to bicarbonate dialysis can be helpful.
Headache is a common symptom during dialysis, the cause of which is largely unknown. It may be a subtle manifestation of the disequilibrium syndrome or may be related to use of acetate-containing dialysis solution. In patients who are coffee drinkers, headache may be a manifestation of caffeine withdrawal as the blood caffeine concentration is acutely reduced during the dialysis treatment.
Acetaminophen can be given during dialysis.
As for nausea and vomiting, a reduction in the blood flow rate during the early part of the dialysis treatment can be tried. A change to bicarbonate-containing dialysis solution is sometimes beneficial.
Chest and back pain
Chest pain (often associated with back pain) occurs in 1-4% of dialysis treatment. The cause is unknown but may be related to complement activation. There is no specific management or prevention strategy other than switching to a synthetic or substituted cellulose membrane. The occurrence of angina during dialysis is common, and this as well as the numerous other potential cause of chest pain (e.g., hemolysis) must be considered in the differential diagnosis.
The treatment of symptoms is supportive, with nasal oxygen and antihistamines. Usually the symptoms are not severe and abate within an hour, and the dialysis treatment can be completed.
This syndrome may be prevented by using a more biocompatible membrane or enrolling the patient in a reuse program using preprocessed new dialyzers.
In general, febrile episodes should be aggressively evaluated with appropriate wound and blood cultures. The suspicion of infection should be particularly high in patients with right atrial dialysis catheters. Fistula or graft infections may be subtle, and empirical treatment with antibiotics may become necessary in many cases.
Febrile reactions during the course of treatment may be related to exposure to endotoxins originating from the dialyzer or dialysate. Such events may be associated with chills, nausea, and more rarely, hypotension. Febrile reactions occurring shortly after treatment are characteristic of systemic infections.
Treatment of endotoxin related fever is generally supportive with antipyretics. In most cases the dialysis treatment can be completed. Infection-related fever is treated with antibiotics administrated at the end of the treatment.
Prevention of endotoxin-related fevers requires effective cleaning and disinfection of dialysis equipment with particular attention to the water-treatment system. In general, the source of such endotoxins will be from contaminated water used for dialyzer reprocessing or for preparing dialysate. However, endotoxin exposure may occur from new dialyzers as well. Clusters of pyrogenic reactions should prompt a thorough review of the procedures for water disinfection and monitoring. Water used in the dialysis unit should have a bacterial content of less than 200 CFU/ml and be free of endotoxin as judged by the limulus amebocyte lysate test. Bicarbonate dialysate should be prepared fresh daily, and if it is prepared in quantity, the holding tank should be relatively small with constant recirculation.
The term first-use syndrome refers to two clinical conditions: an immediate hypersensitivity reaction and a symptom complex of nonspecific chest and back pain. The immediate hypersensitivity reaction is particularly noted with cuprophane membranes.
In many cases an immediate hypersensitivity response may related to IgE-mediated reaction to ethylene oxide used in the sterilization of new dialyzers. Recently, similar reactions have been observed in patients taking angiotensin-converting enzyme (ACE) inhibitors. The symptoms include anxiety, dyspnea, uricaria, and pruitus that may manifest in a wide spectrum of severities, ranging from mild discomfort to true anaphylaxis.
Immediate treatment involves stopping dialysis, clamping the dialysis lines, and discarding the blood and dialyzer. Symptoms are treated supportively with oxygen, antihistamines, bronchodilators, epinephrine, and steroids as required. Dialysis may be resumed with a new dialyzer, preferably of different membrane composition.
Prevention involves adequate dialyzer rinsing before commencing dialysis and, rarely, the use of dialyzers sterilized by other means.
The pathophysiologic basis for uremic pruitus remains to be elucidated. Many dialysis patients have bothersome itching, some of whom experience an exacerbation during or soon after dialysis. Among the many reported etiologic factors is dryness of the skin, secondary hyperparathyroidism, abnormal skin levels of calcium, magnesium, and phosphorus, abnormalities in plasma histamine concentration, or mast cell proliferation.
Treatment has remained largely empirical and includes general measures such as skin lotions and tepid baths as well as antihistamines, oral charcoal, ultraviolet phototherapy or cholestyramine.
Efforts should be made optimize serum calcium and phosphorous concentrations, maintain parathyroid hormone levels within normal limits, and ensure adequate quantities of dialysis.
Cardiopulmonary arrest during dialysis
Catastrophic cardiorespiratory collapse may occur rarely during a dialysis treatment. Decisions must be made quickly as to whether the collapse is due to an intrinsic disease alone or whether technical errors have occurred. Major technical problems include air embolism, unsafe dialysate composition, over-heated dialysate or line disconnection. Air in the dialysate lines, grossly translucent hemolyzed blood, and hemorrhage due to a line disconnection may be immediately apparent.
If the arrest occurs immediately upon initiation of treatment and the cause is unknown, blood should not be returned to the patient. An anaphylactic reaction to the dialyzer membrane or infusion of formaldehyde from an inadequately rinsed reused dialyzer could present as a cardiorespiratory arrest during this initial period. The dialyzer should be checked as to its use number and composition. Formaldehyde infusion is associated with complaints of burning at the access site and, unless the patient had been unable to communicate, should be apparent.
If the event occurs intra-dialytically and there is no reason to suspect problems with dialysate composition, blood should be returned to the patient promptly. A sample of the dialysate should be sent for immediate electrolyte analysis along with the first patient blood samples. The dialyzer and blood lines should be saved for later analysis.
The above assessment is performed simultaneously with removal of the patient from the dialysis chair and placement of the floor, where procedures for cardiopulmonary resuscitation are immediately implemental. Access lines should remain in place to provide a route for administration of saline and medications. After any cardiopulmonary arrest, the dialysis machine should be replaced until all its safety features have been thoroughly evaluated for possible malfunction.