Textbook Of Dialysis Therapy Pdf Download
Imogene Gilley
Objectives:
- Review the history and present status of hemodialysis as a form of renal replacement therapy worldwide.Describe the process, equipment, and trained staff, as well as other specifics of the hemodialysis process.Summarize the associated complications arising out of hemodialysis and their management.Explain the need to ensure teamwork and improved care coordination among the interprofessional team members involved in designing a care plan for renal replacement therapy, creating vascular access, and maintaining it, along with catering to the psychosocial needs of the patients and their families.
The term dialysis is derived from the Greek words dia, meaning "through," and lysis, meaning "loosening or splitting." It is a form of renal replacement therapy, where the kidney's role of filtration of the blood is supplemented by artificial equipment, which removes excess water, solutes, and toxins. Dialysis ensures the maintenance of homeostasis (a stable internal environment) in people experiencing a rapid loss of kidney function, i.e., acute kidney injury (AKI) or a prolonged, gradual loss that is chronic kidney disease (CKD). It is a measure to tide over acute kidney injury, buy time until a kidney transplant can be carried out, or sustain those ineligible for it.
The incidence of renal replacement therapy (RRT) depends on the incidence and prevalence of conditions causing end-stage renal disease (ESRD), early diagnosis of chronic kidney disease (CKD), and measures to slow the progression to end-stage renal disease (ESRD). Systematic identification of patients with a declining estimated glomerular filtration rate (eGFR), heavy proteinuria, and history of acute kidney injury episodes facilitates planned RRT commencement, thus slowing the rising trend in emergency RRT incidence. All patients likely to end up with ESRD and their caregivers must be adequately prepared physically and psychologically and provided with accessible education about future treatment options. Advanced preparation helps avoid dialysis-associated complications such as a malfunctioning catheter or poorly functioning fistula, causing temporary vascular access insertion culminating in sepsis, thrombosis, bleeding, and accelerated mortality. Patients with educational programs are more likely to choose home-based dialysis therapy with societal benefits, less expenditure, and improved quality of life. These programs should commence no later than stage 4 CKD for the patient to have sufficient time and cognition to make informed choices and implement preparatory measures for RRT.
In 2010, approximately 2.5 million people worldwide received chronic RRT, with high absolute rates in North America and maximum prevalence in Taiwan and Japan. Maintenance of regional and national dialysis registries with details on rates, outcomes, and national dialysis practice patterns helps keep track of the population dependent on RRT. They also include hospital-specific information, safety, and quality reporting and provide resources for clinical research. Opting for dialysis is affected by sociocultural and socioeconomic factors. ESRD is disproportionately higher in African Americans and CKD among the White population. ESRD burden is attributed to diabetes mellitus (45%) and hypertension (30%), besides rarer causes like polycystic kidney disease, obstructive nephropathy, and glomerulonephritis. Women are at higher risk for CKD, while men have a higher risk of ESRD. Race disparities can limit access to health care due to their impact on income or the availability of health insurance. Indigenous people in Australia, New Zealand, the United States, and Canada have high rates of kidney disease, less access to transplantation, and poorer outcomes. There are three broad types of dialysis:
The dynamics of this particular form of renal replacement therapy vary across countries with longer dialysis sessions and slower blood flow rates in Japan. PD is highly prevalent in Hong Kong and the Jalisco region of Mexico, while Home HD is widely adopted in New Zealand and Australia.
The timing for initiation of dialysis is decided after considering the complications of early initiation (unnecessary exposure to IV lines and invasive procedure with risks of infection) against late initiation, causing avoidable volume, metabolic, and electrolyte complications of AKI. Assigning arbitrary urea nitrogen or creatinine level for dialysis initiation is not advisable due to individual variability in uremia symptom severity and renal function. Despite optimal CKD management, patients progress to needing RRT, especially when their eGFR drops below 20 ml/ min/1.73 m2 or they rapidly deteriorate to ESRD within 12 months. The eGFR at dialysis initiation has steadily increased in recent times. In 1996, in the United States, 13% of incident ESRD patients started RRT at an eGFR of 10 ml/min/1.73 m2 or higher. This increased to 43% in 2010 and dropped to 39% in 2015. Waiting for uremic symptoms to set in before commencing RRT had added risks of the patient being malnourished with increased mortality risk. Asking patients to compare their current eating habits and physical activity levels with those 6 to 12 months back helps avoid the lack of awareness. The concept of a 'healthy start,' with dialysis commencing before the onset of severe uremia symptoms, is associated with prolonged survival. An early start will prepone the need for a change of modality or further procedures without any improvement in the quality of life while adding to healthcare costs. The Renal Physicians Association's (RPA) criteria for identifying dialysis patients with a poor prognosis beyond 75 years of age includes:
Mortality rates among dialysis patients are markedly higher among younger age groups, primarily attributed to cardiovascular (40%) and infectious causes (10%). High cardiovascular mortality in dialysis patients could be related to shared risk factors such as chronic inflammation, significant changes in extracellular volume, dystrophic vascular calcification, and altered cardiovascular dynamics during dialysis. The study of heart and renal protection (SHARP) having dialysis and non-dialysis requiring CKD patients showed a 17% reduction in cardiovascular death and major cardiovascular events with simvastatin-ezetimibe treatment. Cardioprotective strategies such as beta-blockers, aspirin, and renin-angiotensin-aldosterone system inhibitors are recommended in dialysis patients based on their cardiovascular risk profile. Hypertension has a graded association with ESRD risk as it is both a cause and a consequence of CKD. The first three months after dialysis initiation, especially among older patients, has the highest mortality rates. This could be due to risks associated with the commencement of dialysis (central venous catheter placement) and more severe comorbidities causing deterioration of renal function. Effective interprofessional collaboration is needed to improve overall outcomes in patients with ESRD requiring dialysis.
The Kt/V urea was a parameter introduced by Gotch and Sargent through their National Cooperative Dialysis Study (1985). It was noted that a Kt/V of less than 0.8 was associated with higher morbidity or treatment failure as opposed to a Kt/V of more than 1.0, which produced a good outcome. It is a dimensionless ratio obtained by dividing the amount of plasma cleared of urea (Kt) by the distribution volume of urea (V). The urea-free plasma volume is a product of K, which is blood urea clearance, and t, which is the dialysis session length. A Kt/V of 1.0 implies that the total blood volume cleared during a session equals the urea distribution volume.
It recommends that patients who reach CKD stage 4 (GFR, 30 mL/min/1.73 m^2), and those with an imminent need for maintenance dialysis during the initial assessment, should be counseled about renal failure and the treatment options (kidney transplantation, hemodialysis at home or in-center, PD) and conservative treatment. Family members and caregivers should also be educated. The decision to initiate maintenance dialysis should be based on an assessment of signs and symptoms of renal failure (pruritus, acid-base or electrolyte abnormalities, serositis), volume or BP dysregulation, and a progressive deterioration in nutritional status despite dietary intervention or impairment in cognition. The decision to initiate dialysis should not be based on the level of kidney function in an asymptomatic individual.
Cardiac conditions requiring dialysis are arrhythmias due to electrolyte derangements, uremic pericarditis, and fluid overload due to severe congestive heart failure precipitated by suboptimal kidney function. After structural cardiac abnormalities, electrolyte (calcium, magnesium, and potassium) derangements are the most common arrhythmias. Metabolic acidosis and decreased renal excretion in chronic kidney disease or renal failure patients lead to potassium abnormalities. Iatrogenic causes in cardiac patients are an improper use of ACE inhibitors, angiotensin-receptor blockers, and aldosterone antagonists. In renal failure patients, elevated urea levels can also lead to uremic pericarditis. Patients with CKD and heart failure experience fluid retention, which leads to worsening heart failure and pulmonary edema.
Where the patient can clearly express the wish to decline dialysis treatment, the provider is obliged to respect this decision. Nonetheless, the nephrologist must ensure adequate addressing of all reversible factors, such as unfounded fears about the dialysis process or a depressive illness clouding the judgment and requesting a psychiatric evaluation. In such patients, especially those with multiple comorbidities, a shift is made to conservative management using all proper treatments apart from dialysis.
Patients with unacceptable quality of life should be spared the discomfort of HD as survival on dialysis may be no longer with most of the additional time spent on having or recovering from dialysis sessions. Symptomatic treatment of ESRD and its complications can be done with medication and diet, such as pain management with analgesics. In addition, low doses of gabapentin or pregabalin can be used for severe itching and insomnia.
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