Week 12 Lecture Slides on Chronic Kidney Disease PDF

EHR522 EXERCISE FOR METABOLIC & RENAL CONDITIONS WEEK 12 – CHRONIC KIDNEY DISEASE CHRONIC KIDNEY DISEASE (CKD) • CKD results from structural renal damage and progressively diminished renal function • After CKD begins, it can progress to end-stage renal disease (ESRD), requiring some form of renal...

EHR522 EXERCISE FOR METABOLIC & RENAL CONDITIONS WEEK 12 – CHRONIC KIDNEY DISEASE CHRONIC KIDNEY DISEASE (CKD) • CKD results from structural renal damage and progressively diminished renal function • After CKD begins, it can progress to end-stage renal disease (ESRD), requiring some form of renal replacement therapy (RRT) such as dialysis (haemodialysis or peritoneal dialysis), transplantation or conservative management if RRT is not done 2 CHRONIC KIDNEY DISEASE (CKD) • CKD is defined as the presence of kidney damage (usually detected as urinary albumin excretion of ≥ 30 mg/d, or equivalent) or decreased kidney function (defined as estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73m2) for three months or more, irrespective of the cause • Many CKD patients do not progress to ESRD but instead die prematurely or cardiovascular disease 3 SCOPE • According to current estimates, approximately 14% of the US adult population have CKD • Renal replacement therapy is expensive. In 2013, the reported cost of haemodialysis was $84,550 per patient per year; kidney transplant costs less over time • The sedentary behaviour that is characteristic of patients with CKD contributes to the excess morbidity and mortality observed in this population 4 STAGING CRITERIA FOR CKD 5 RISK FACTORS FOR CKD • Risk factors for CKD include − Diabetes − Hypertension − Cardiovascular disease − Family history of renal disease − Obesity − Smoker − 60 years or older − Identifying as Indigenous Australian − History of acute kidney injury 6 PATHOPHYSIOLOGY • Damage to the kidney is due to longstanding diabetes mellitus or hypertension, autoimmune disease (eg. lupus), glomerulonephritis, pyelonephritis, some inherited diseases (ie. polycystic kidney disease, Alport Syndrome) and congenital abnormalities • The initial injury to the kidney may result in a variety of clinical manifestations, ranging from asymptomatic haematuria to renal failure requiring dialysis. Many individuals fully recover and subsequently suffer from little to no consequences. 7 PATHOPHYSIOLOGY • The kidney is able to adapt to damage by increasing the filtration rate in the remaining normal nephrons, a process called adaptive hyperfiltration. As a result, the patient with mild renal insufficiency often has a normal or near-normal serum creatinine concentration • Additional homeostatic mechanism (most frequently occurring in the renal tubules) permit the serum concentration of sodium, potassium, calcium and phosphorous and the total body water to also remain within the normal range, particularly among those with mild to moderate renal failure • Adaptive hyperfiltration, although initially beneficial, appears to result in long-term damage to the glomeruli of the remaining nephrons, which is manifest by proteinuria and progression to renal failure 8 PATHOPHYSIOLOGY • The initial decline in renal function in patients with CKD is initially asymptomatic. The damaged kidney initially responds with higher filtration and excretion rates per nephron, which masks symptoms until only 10 – 15% of renal function remains • Progressive renal failure causes loss of excretory and regulatory functions, which leads to ESRD and results in uraemic syndrome 9 PATHOPHYSIOLOGY • Manifestations of the uraemic state include − Anorexia − Nausea − Vomiting − Fatigue − Pericarditis − Peripheral neuropathy − Central nervous system abnormalities (ranging from loss of concentration and lethargy to seizures, coma and death) • No direct correlation exists between the absolute serum levels of blood urea nitrogen (BUN) or creatinine and the development of these symptoms 10 PATHOPHYSIOLOGY • Patients identify with the previously identified, as well as − Peripheral oedema − Pulmonary oedema − Congestive heart failure • To continue life, uraemic patients require the institution of RRT using haemodialysis, peritoneal dialysis or renal transplantation • The loss of the excretory function of the kidney results in the build-up of toxins in the blood, any of which can negatively affect cellular enzyme activities and inhibit systems such as the sodium pump, resulting in altered active transport across cell membranes and altered membrane potentials 11 PATHOPHYSIOLOGY • The loss of the regulatory function of the kidneys results in the inability to regulate extracellular fluid volume and electrolyte concentrations, which adversely affects cardiovascular and cellular functions • Most patients with advanced CKD are volume overloaded; this results in hypertension and often congestive heart failure • Other malfunctions in regulation include impaired generation of ammonia and hydrogen ion excess, which results in metabolic acidosis and decreased production of erythropoietin, the primary reason for the anaemia observed in patients with ESRD 12 PATHOPHYSIOLOGY • Other hormones that are normally released may be excessively produced or inappropriately regulated in response to renal failure. Parathyroid hormone may be the most important of these, in that this chemical is produced in excess secondary to renal failure-induced hyperphosphataemia; there is reduced conversion of vitamin D to its active form • Several metabolic abnormalities are associated with uraemia; including insulin resistance and hyperglycaemia; dialysis is associated with hypertriglyceridaemia with normal (or low) total cholesterol concentrations. Also, some of the treatments associated with dialysis or immunosuppression therapy (following transplant) can contribute to these metabolic abnormalities 13 CLINICAL CONSIDERATIONS • Treatment is multi-pronged and typically involves control of blood pressure and diabetes, use of an angiotensin-converting enzyme inhibitor / angiotensin receptor blocker (ACEI/ARB), lowering urine protein, weight loss as needed, smoking cessation and regular exercise • Dietary adjustments for protein, sodium and fluid intake play an important role in the initial management of renal failure. • If these treatments are not successful, RRT is required. Transplantation is the preferred method, but patients need to be free of other life-threatening illnesses to be considered for transplantation 14 CLINICAL CONSIDERATIONS • Haemodialysis is the most common therapy for renal failure, although it requires significant time throughout the week at a renal centre (dialysis unit) • The third RRT option, peritoneal dialysis, is the method least used 15 CLINICAL CONSIDERATIONS • CKD patients often present with symptoms and signs resulting directly from diminished kidney function. These include − Oedema − Hypertension − Decreased urine output • However, many patients have no clinical symptoms. In such patients, kidney disease is detected by laboratory tests that are obtained as part of an evaluation for an unrelated disorder 16 CLINICAL CONSIDERATIONS Signs include – Anaemia – Fluid build-up in tissues – Loss of bone minerals – Hypertension Patients complain of – Fatigue – Shortness of breath – Loss of appetite – Restlessness – Change in urination patterns – Overall malaise • Muscle mass, muscle endurance and peak oxygen uptake all decline as the disease progresses 17 HISTORY AND PHYSICAL EXAMINATION • Longstanding diabetes and severe hypertension and common causes of CKD • You should pay particular attention to any cardiac history and the type and frequency of dialysis treatment, information needed in order to develop the best strategy for exercise that considers the treatment burden experienced by the patient 18 DIAGNOSTIC TESTING AND TREATMENT • Management of CKD is directed at minimising the consequences of accumulated uraemic toxins that are normally excreted by the kidneys • Dietary measures play a primary role in the initial management, with very-low protein diets being prescribed to decrease the symptoms of uraemia and possibly to delay the progression of the disease • In addition to protein restriction, dietary sodium, phosphate and fluid restrictions are critical as well, because the fluid regulation mechanisms of the kidney are deteriorating. Therefore, excess fluids consumed remains in the system, and with progressive deterioration in renal function, ultimately results in peripheral oedema, congestive heart failure and pulmonary congestion 19 DIAGNOSTIC TESTING AND TREATMENT • The decision to begin dialysis is determined by many factors, including − Cardiovascular status − Electrolyte levels (specifically potassium) − Chronic fluid overload − Severe and irreversible oliguria (ie. urine output less than 0.5 mL/kg of body weight divided by height) − Anuria (ie. absence of urine output) − Significant uraemic symptoms − Abnormal laboratory values (creatinine, blood urea nitrogen and creatinine clearance) • RRT does not correct all signs and symptoms or uraemia and often results in other concerns and side effects 20 HAEMODIALYSIS • Haemodialysis is the most common form of RRT • Approximately 95% of all patients undergo haemodialysis in a centre (dialysis unit) or at home • In other countries, some patients prefer home-based methods such as peritoneal dialysis • Haemodialysis is a process of ultrafiltration (fluid removal) and clearance of toxic solutes from the blood. It necessitates vascular access by one of three methods − A fistula − A graft − A central venous catheter 21 HAEMODIALYSIS • Fistula – The name for joining an artery to a vein. Usually created by a small operation on the anterior forearm of the non-dominant limb. The most common access method that we will refer to for the remainder of the lecture. Fistulas provide the best long-term vascular access and have the lowest risk of complications • Graft – If the veins are too small or delicate for a fistula to be effective, then a graft may be needed. This is an artificial tube which is placed in the arm or leg. One end is attached to an artery and the other end is attached to a vein. The needles for dialysis are placed into the graft 22 HAEMODIALYSIS • Central Venous Catheter – Sometimes it is not possible to create a fistula or a graft. In these cases vascular access is with a central venous catheter. This is a soft plastic tube that is placed into a large vein in the chest. Central venous catheters have an increased risk of infection, particularly if not managed carefully. They also have a higher incidence of getting blocked and are usually not suitable for long term use 23 HAEMODIALYSIS • Two needles are placed in the fistula; one directs blood out of the body to the artificial kidney (dialyzer), and the other directs blood back into the body • The dialyzer has a semi-permeable membrane that separates the blood from a dialysis solution, which creates an osmotic and concentration gradient to clear substances from the blood • Factors such as characteristics of the membrane, transmembrane pressures, blood flow and dialysate flow rate determine removal of substances from the blood 24 HAEMODIALYSIS • Manipulation of the blood flow rate, dialysate flow rate, dialysate concentrations and time of the treatment can be used to remove more or less substances and fluids • The duration of the dialysis treatment is determined by the degree of residual renal function, body size, dietary intake and clinical status • A typical dialysis prescription is 3 to 4 hours, three times per week 25 COMPLICATIONS ASSOCIATED WITH HAEMODIALYSIS 26 PERITONEAL DIALYSIS • Approximately 6.9% of dialysis patients are treated with peritoneal dialysis • This form of therapy is accomplished via introduction of a dialysis fluid into the peritoneal cavity through a permanent catheter placed in the lower abdominal wall • The peritoneal membranes are effective for ultrafiltration of fluids and clearance of toxic substances in the blood of uraemic individuals • The peritoneal barrier is composed of three layers, including the peritoneal mesothelium, the interstitium and the capillary endothelium 27 PERITONEAL DIALYSIS • The dialysis fluid is formulated to provide gradients to remove fluid and substances from the bloodsteam • The fluid is introduced either by a machine (cycler), which cycles fluid in and out over an 8 to 12 hour period at night, or manually with 2 – 2.5 L bags that are attached to tubing and emptied by gravity into and out of the peritoneum • The latter process, known as continuous ambulatory peritoneal dialysis, allows the patient to dialyse continuously throughout the day • Continuous ambulatory peritoneal dialysis requires exchange of fluid every 4 hours using a sterile technique 28 PERITONEAL DIALYSIS • Patients choose peritoneal dialysis so they can experience more freedom and less dependency on a centre for use of a machine. This method of treatment allows patients to travel and dialyse on their own schedules • Patients who have cardiac instability may also be placed on peritoneal dialysis because this method does not involve the major fluid shifts experienced with haemodialysis 29 PERITONEAL DIALYSIS • Complications of peritoneal dialysis are due to increased intraabdominal pressure resulting from instillation of dialysate into the peritoneal cavity and include problems with the catheter or catheter-site, such as − Infection − Hernias − Low back pain − Obesity − Gastroesophageal reflux − Delayed gastric emptying • Patients may absorb as many as 1,200 kcal from the dialysate per day, contributing to the development of obesity and hypertriglyceridaemia 30 LONG TERM COMPLICATIONS OF DIALYSIS 31 KIDNEY TRANSPLANT • Transplantation of kidneys is the preferred treatment of ESRD • The source of the kidneys available for transplant can be a living relative, an unrelated individual or a cadaver • Because of the shortage of organs available for transplantation and improvements in immunosuppression medications, living non-related transplants are becoming more frequent • Following transplantation, patients are placed on immunosuppression medication, which includes combinations of glucocorticosteroids (prednisone), a cyclosporine and monoclonal antibody therapy 32 KIDNEY TRANSPLANT • New immunosuppression medications are constantly being developed, allowing for minimisation of side effects through alteration of therapies or combinations of therapies • Patients may experience rejection either early (acute) or later (chronic), which is detected by elevation of creatinine • Rejection is treated immediately with increased dosing of immunosuppression (mostly prednisone), with a subsequent tapering back to a maintenance dose • Patients must remain on immunosuppression for the lifetime of the transplanted organ • 1 year patient survival is 90% and 5 year patient survival is 85% 33 KIDNEY TRANSPLANT • Complications of kidney transplantation are primarily related to immunosuppression therapy and include – Infection – Hyperlipidaemia – Hypertension – Obesity – Steroid-induced diabetes – Osteonecrosis • The incidence of atherosclerotic cardiovascular disease is four to six times higher in kidney transplant recipients than in the general population, and cardiovascular risk factors are prevalent in most patients 34 LONG TERM COMPLICATIONS ASSOCIATED WITH KIDNEY TRANSPLANTATION 35 THE EFFECT OF CKD ON THE EXERCISE RESPONSE The exercise response in patients with CKD is typically characterised by − Progressively lower peak exercise capacity − Earlier muscle fatigue, limiting exercise capacity − Lower maximal heart rates − Hypertensive pressor response (increase in arterial blood pressure) – particularly in low to moderate intensity exercise 36 EXERCISE TESTING • The functional capacity of CKD patients before starting dialysis is approximately 21 +/- 5 mL/kg/min, which represents 50 – 80% of age-matched healthy controls • As the disease progresses, functional capacity decreases, such that by the time stage 5 is reached peak VO2 is only 17 – 20 mL/kg/min, which can be as low as 39% of age-matched healthy controls • It is important to note that peak VO2 is an independent risk factor of mortality in these patients 37 EXERCISE TESTING • The degree to which exercise capacity is limited in patients with CKD is difficult to determine because reduced exercise capacity is almost certainly a multi-factorial problem that is influenced by – Anaemia – Muscle blood flow – Muscle oxidative capacity – Myocardial function – The person’s activity levels • In ESRD, muscle function may be affected by nutritional status, dialysis adequacy, hyperparathyroidism and other clinical variables 38 EXERCISE TESTING • Most studies that have measured VO2 peak have included only the healthiest patients with CKD; thus, the average CKD patient may have an even lower exercise capacity • One school of opinion holds that information obtained from graded exercise testing in this patient group, particularly patients with stage 5 CKD, is not diagnostically useful since most patients stop exercise because of leg fatigue and do not achieve age-predicted maximal heart rates 39 EXERCISE TESTING • Furthermore, many patients have abnormal left ventricular function, and some have conditions that make interpretation of the stress electrocardiogram difficult; these include - Left ventricular hypertrophy (LVH) strain patterns - Electrolyte abnormalities - Digoxin effects on the ECG • Thus exercise stress testing in ESRD patients may not be routinely performed before initiation of exercise training, and requiring that such a test first be completed may prevent some patients from becoming more physically active 40 EXERCISE TESTING • Because exercise capacity is so markedly reduced in stage 5 patients, most patients do not exercise train at an intensity level that is much greater than the energy requirements of their daily activities. Therefore, the risk associated with such training is minimal • However, patients with CKD not yet undergoing dialysis can exercise at moderate and even higher intensities, in much the same manner as healthy individuals • Caution should be taken if heart rate is used for determining training intensity in patients with stage 5 disease because heart rate response can be influenced by medication and uraemia. • If an exercise test is used, an individualised heart rate range can be developed for each patient if they are taking their medications as prescribed 41 EXERCISE TESTING • In patients with ESRD, it may be better to measure physical performance using standard functional tests such as the Short Physical Performance Battery, 6 Minute Walk Test, Sit-to-Stand Test or gait speed testing • Research shows that exercise training improves the functional scores on self-reported scales in haemodialysis patients • Exercise capacity is similarly low in peritoneal dialysis patients • Following successful renal transplant, exercise capacity increases significantly, to near-sedentary normal predicted values • Exercise heart rate responses are normalised after transplant; however, the increase in blood pressure during exercise is often excessive or abnormal 42 EXERCISE TESTING REVIEW 43 THE EFFECT OF COMMON PHARMACOTHERAPY AGENTS 44 EXERCISE TRAINING AND THE PROGRESSION OF CKD • There is evidence from animal studies that exercise training can favourably alter kidney function, but similar evidence is inconsistent in human studies • Specifically, some researchers have found no evidence for improvement in kidney function following moderate-intensity continuous aerobic exercise performed three to five times per week for 12 – 18 months in CKD patients • Conversely, others have observed encouraging evidence of either an improvement in GFR or a reduction in the rate of GFR decline in persons who engage in aerobic exercise training 45 EXERCISE TRAINING AND THE PROGRESSION OF CKD • These inconsistent findings have been attributed to the small sample sizes used in most of these studies, the relatively short duration of these studies and the known variability in the measurement of GFR • However, what has consistently emerged from all the exercise studies performed in CKD patients not yet treated with dialysis is the fact that exercise training does not harm kidney function • Apart from its effects on the kidneys, exercise training in CKD improves overall fitness and seems to be of some benefit on resting blood pressure and visceral fat, but it has little observed beneficial effect on serum lipids 46 EXERCISE PRESCRIPTION • The exercise prescription for CKD patients should be comprehensive and include aerobic, resistance and flexibility exercises • Please note, however, that the ideal exercise prescription for pre-dialysis CKD patients has not been identified • Weight management considerations may also be needed for any patients who are overweight or obese, which is common in this population 47 EXERCISE PRESCRIPTION • When prescribing exercise for patients being treated with dialysis, it is important to appreciate that multiple barriers to exercise may exist. These include general feelings of mailaise, time requirements of treatment, fear and adaptation of lifestyles to low levels of functioning • Thus, any prescription should begin with a lower volume of exercise and gradually progress to prevent discouragement and additional feelings of fatigue or muscle soreness 48 CLIENT-CLINICIAN INTERACTION • Given that the ideal exercise prescription for CKD patients has not been identified, recommendations for comorbidities can be followed • Concerning patients undergoing haemodialysis, most receive their treatments three times per week for 3 – 4 hours, and following these treatments patients tend to feel fatigued for much of the day • To optimise adherence, consideration should be given to participating in supervised exercise classes on those days when the patient is not scheduled for dialysis or potentially implementing exercise programs at the dialysis unit 49 CLIENT-CLINICIAN INTERACTION • The dialysis staff are close to the patients and can be influential in their participation (or nonparticipation) in exercise • This support is important for both the long-term adherence of the patient and the integration of the exercise personnel in the patient’s overall care 50 SPECIAL EXERCISE CONSIDERATIONS • Many CKD patients live sedentary lives and are not accustomed to being physically active • Cardiovascular disease is the main cause of death in CKD patients; a CKD patient is more likely to die from cardiovascular disease than to progress to ESRD • In general, patients with CKD not yet receiving dialysis are likely to be diabetic, hypertensive and overweight or obese. Therefore, any exercise recommendations should be made with these comorbid conditions in mind 51 SPECIAL EXERCISE CONSIDERATIONS • Most research to date involving patients with CKD has focused on patients with ESRD; therefore, more is known about the exercise considerations in this population • Patients with ESRD often do not know how much activity is too much activity, and because they may not feel well and are easily fatigued, they avoid physical activity 52 SPECIAL EXERCISE CONSIDERATIONS 53 SPECIAL EXERCISE CONSIDERATIONS – HAEMODIALYSIS PATIENTS Special considerations for haemodialysis patients − Patients have extremely low fitness levels − Timing of exercise sessions should be coordinated with dialysis sessions; non-dialysis days are usually preferred − Patients will require frequent hospitalisations and will experience setbacks − Gradual progression is crucial − Heart rate prescriptions are typically invalid – use of RPE is recommended − Maximal exercise testing may not be feasible in all patients but should be used whenever appropriate − Performance-based testing should be used in patients who cannot tolerate graded exercise testing − Prevalence of orthopaedic problems is significant 54 SPECIAL EXERCISE CONSIDERATIONS – HAEMODIALYSIS PATIENTS Special considerations for haemodialysis patients – continued… • 1RM testing for strength is not recommended because of secondary hyperparathyroidism-related bone and joint problems • Motivating patients is often a challenge • Every attempt should be made to educate dialysis staff about the benefits of exercise so they can help motivate patients to participate DO NOT TAKE BLOOD PRESSURE ON THE FISTULA ARM DO NOT USE THE FISTULA ARM FOR EXERCISE DURING DIALYSIS 55 SPECIAL EXERCISE CONSIDERATIONS – TRANSPLANT PATIENTS Special considerations for transplant patients − Patients are initially weak, so gradual progression is recommended − Patients may experience a lot of orthopaedic and musculoskeletal discomfort with strenuous exercise − Weight management often becomes an issue following transplant − Patients and their families are often fearful of over-exertion; thus, gradual progression should be stressed − Prednisone may delay adaptations to resistance training − Exercise should be decreased in intensity and duration during episodes of rejection, not eliminated completely − Patients may experience frequent hospitalisations during the first year after the transplant. Because patients are immunosuppressed, every effort must be made to avoid infectious situations (e.g. strict sterilisation procedures must be followed for exercise testing and training equipment) 56 CONTRAINDICATIONS TO EXERCISE IN ESRD Contraindications to exercise in ESRD − Electrolyte abnormalities – especially hypo- or hyper-kalaemia − Recent changes to the ECG, especially symptomatic tachy- or brady-arrhythmias − Excess inter-dialytic weight gain (> 4kg) since last dialysis or exercise session (remember that in CKD there is an overactivation of the renin-angiotensin system and a subsequent increase in aldosterone secretion that causes the oedema) − Unstable on dialysis treatment and changing (titrating) medication regime − Pulmonary congestion − Peripheral oedema 57 ADDITIONAL POINTS TO CONSIDER WITH EXERCISE IN CKD • Note that microalbuminuria (a moderate increase in protein albumin in urine) in itself does not necessitate restriction in exercise • The Valsalva Manoeuvre should be avoided in patients with nephropathy to prevent excessive rises in blood pressure • Many patients with CKD have concurrent CAD and PVD and that those with PVD are at higher risk of CAD • Whilst exercise in those with CAD should be 10 – 15 beats/min below the angina threshold, exercise intensity in those patients with PVD does not need to be regressed if/when they experience calf pain 58 RESEARCH DATA • There is evidence to indicate that replacing as little as 2 minutes/hour of sedentary behaviour with even light-intensity activity (ie. 2 – 2.9 METs) significantly reduces mortality risk in CKD patients • On the basis of the available data, CKD patients, across the spectrum of the disease, should be encouraged to adhere to the physical activity guidelines (ie. at least 150 minutes of moderate to vigorous physical activity each week) in addition to reducing sedentary time. 59 RESEARCH DATA • Among patients with CKD, researchers have shown that various exercise training interventions of 4 – 6 months are associated with marked improvements in cardiorespiratory fitness (up to 20%), reductions in markers of inflammation and improvements in muscle strength • Resistance training programs lead to improvements in muscular strength in all stages of CKD • Changes in plasma lipids in response to exercise training seem to be attenuated in patients with CKD, and body composition changes are variable 60 RESEARCH DATA • Other benefits associated with exercise training include a reduction in depression scores and improvements in health-related quality of life indices • Improvements in heart rate variability have also been reported, with a shift toward greater vagal tone following exercise training • In general, the findings of significant benefits from exercise training in CKD patients seem to be stronger in the ESRD population, possibly because most of the exercise studies to date have been done in this cohort 61 EXERCISE RECOMMENDATIONS • Patients with CKD who have not yet started dialysis have been shown to benefit from exercise training programs using standard exercise prescriptions for the general population, so long as the individuals are screened properly, start at a low to moderate intensity and progress gradually • With regard to patients with ESRD, the timing of exercise in relation to the dialysis treatment should be considered • Exercising during treatment (intra-dialytic exercise) is recommended since is has significant physiologic benefit (reduces the likelihood of cramping and hypotension during dialysis), enhances exercise compliance and reduces the boredom associated with dialysis treatments 62 EXERCISE RECOMMENDATIONS • Exercising immediately before (when many patients may be experiencing fluid overload) or after dialysis (when fatigue and hypotension are common) is generally not well tolerated and therefore not recommended • Research in haemodialysis patients demonstrates that larger adaptations usually occur when exercise is completed on non-dialysis days, but that intra-dialytic exercise is likely to produce better adherence rates • Exercise should be deferred if the patient is experiencing shortness of breath related to excess fluid status. No specific guidelines regarding the upper limit of fluid weight gain contraindicate exercise (though > 4kg has been suggested to be reasonable) 63 EXERCISE RECOMMENDATIONS • Intra-dialytic exercise is highly recommended for haemodialysis patients. The ideal mode of exercise is recumbent stationary cycling. This form of exercise does not interfere with the dialysis treatment and should be encouraged in most dialysis clinics. If this is not possible, a home exercise program may be the next best approach for these patients • Cycling during dialysis is best tolerated during the first 1 – 1.5 hours of the treatment because after that time the patient has a greater risk of becoming hypotensive even while sitting in the chair, which makes cycling difficult 64 EXERCISE RECOMMENDATIONS • This hypotensive response is caused by the continuous removal of fluid (including intravascular) throughout the treatment, which decreases cardiac output, stroke volume and mean arterial pressure at rest. Therefore, after 2 hours of dialysis, cardiovascular decompensation may contraindicate exercise • For patients treated with continuous ambulatory peritoneal dialysis, the exercise may be best tolerated at a time when the abdomen is drained of fluid; this allows for greater diaphragmatic excursion and less pressure against the catheter during exertion, reducing the risk of hernias or leaks around the catheter site 65 EXERCISE RECOMMENDATIONS - MODE • There are no restrictions on the type of activity that can be prescribed for patients with CKD, including those not yet using dialysis, those undergoing dialysis, or patients having undergone transplant • Many ESRD patients have poor musculoskeletal function and experience joint discomfort; therefore, non-weight bearing cardiovascular-type activity may be best tolerated • As with apparently healthy individuals, if jarring or ballistic activity causes joint discomfort, then a change in mode of exercise is indicated 66 EXERCISE RECOMMENDATIONS - MODE • The vascular access site used for the haemodialysis may be in the arm or upper leg • The location should not inhibit physical activity at all, although many patients are initially told not to use the arm with the arteriovenous fistula in it for 6 – 8 weeks after it is implanted to ensure sufficient time for post-operative healing • The only precaution for the fistula is to avoid any activity that would close off the flow of blood (eg. having weights lying directly over the top of the vessels) • Although the patient should be protective of the access site, use of the extremity will increase flow through it and actually help develop muscles around the access site, which makes the placement of needles easier 67 EXERCISE RECOMMENDATIONS - MODE • Patients with a peritoneal catheter should avoid full situps and activities that involve full flexion at the hip • Patients with a peritoneal catheter usually find it more comfortable and tolerable to exercise when their abdominal cavity is empty • Swimming may be a challenge for those with peritoneal catheters because of the possibility of infection. Patients must be advised to cover the catheter with protective tape and to clean around the catheter exit site after swimming • As a general rule, it is wise to avoid hydrotherapy exercise with patients who have a peritoneal catheter 68 EXERCISE RECOMMENDATIONS - MODE • Although renal transplant recipients are often told not to participate in vigorous activities, the actual primary concern is avoiding any contact sport (eg. football) that may result in a direct hit to the area of the transplanted kidney • Vigorous non-contact sports and activities are generally well tolerated by transplant recipients who have exercise trained to attain adequate muscle strength and cardiorespiratory endurance through a comprehensive conditioning program 69 EXERCISE RECOMMENDATIONS - FREQUENCY • Cardiorespiratory exercise should be prescribed 3 – 5 days/week as recommended for the general population • Resistance exercise should be performed 2 – 3 days/week • Flexibility exercises should be performed whenever CKD patients exercise train; however, because of the stiffness that patients with ESRD experience after prolonged periods of sitting in dialysis chairs, they should be encouraged to stretch daily 70 EXERCISE RECOMMENDATIONS - INTENSITY • Patients with CKD who are not receiving dialysis can be prescribed aerobic exercise training at a moderate to vigorous intensity (ie. 50 – 80% VO2 reserve). However, since many of these patients could be taking medications that affect heart rate or have diabetes, these issues need to be considered if you want to use a heart-rate based method to gauge exercise intensity • In patients with ESRD, exercise intensity should be guided by RPE, because heart rates are highly variable in this patient population as a result of fluid shifts and vascular adaptations to fluid loss during the dialysis treatment. Furthermore, peak heart rate in ESRD patients is lower than for normal age- and gendermatched controls 71 EXERCISE RECOMMENDATIONS - INTENSITY • Many ESRD patients may initially tolerate only a few minutes of very low-level exercise, which means that any formal warm-up and cool-down intensities are less relevant. These individuals should just be encouraged to increase duration gradually at whatever level of effort they can tolerate • In general, an RPE of 12 – 15 should be used • For resistance exercise, CKD patients can be prescribed workloads up to 75% of their estimated 1RM 72 EXERCISE RECOMMENDATIONS – DURATION AND PROGRESSION • Pre-dialysis CKD patients can often start with 15 – 20 minutes of lower-intensity continuous exercise, but this may need to be modified for some individuals who are deconditioned, for which an interval-type method may be necessary • ESRD patients tend to be very deconditioned and may need to be treated differently; determine the duration of activity they can comfortably tolerate during the initial sessions. This duration will be the starting duration of activity 73 EXERCISE RECOMMENDATIONS – DURATION AND PROGRESSION • If the patient tolerates only 2 – 3 minutes of continuous exercise, the prescription may be written for three to four intervals of 2 – 3 minutes each, with a gradual decrease in rest times as the patient is progressed to continuous activity • A progressive increase in duration of 2 – 3 minutes per session or per week is recommended, depending on individual tolerance • Extremely deconditioned patients may need to start with flexibility exercises and a resistance program of lower workloads (based on 10RM) and higher repetitions (10 – 15) before beginning any cardiorespiratory activity 74 EXERCISE RECOMMENDATIONS – DURATION AND PROGRESSION • When a patient begins cycling during dialysis, the initial session is usually limited to 10 minutes, even if the patient is able to tolerate a longer duration. This precaution assures the dialysis staff and the patient that cycling does not have any adverse effects on the dialysis treatment. The patient can then increase duration in subsequent sessions according to tolerance • RPE is also used for intensity prescription during the dialysis treatment, because removal of fluid from the beginning to the end of dialysis can cause resting and exercise heart rates (at standard sub-maximal level) to vary by 15 – 20 beats/minute 75 EXERCISE TRAINING • Since a deterioration in physical function over time is often associated with CKD, then maintenance or prevention of loss in exercise capacity and physical function over time may be viewed as a favourable outcome for some patients • Transplant recipients and patients who undergo dialysis respond to exercise training with a magnitude of change in strength and exercise capacity that is similar to that for healthy individuals. However, they may not achieve similar maximal levels of functioning. Likewise, the time course for improvement may be longer in patients with renal disease 76 EXERCISE TRAINING REVIEW FOR ESRD PATIENTS TREATED WITH DIALYSIS OR RECEIVING A TRANSPLANT 77 CONCLUSION • The goal is for patients to become more active in general, to decrease time spent in sedentary behaviour, and, if possible, to work toward a regular exercise program of 3 – 5 days/week of cardiorespiratory exercise for 30 minutes or more per session, at an intensity of 12 – 15 on the RPE scale • Engaging in resistance exercise two or three times per week is also highly recommended 78 WEEKLY READING Ehrman, K. J. (2022). Clinical Exercise Physiology (5th ed.). Chapter 13: Chronic Kidney Disease. Human Kinetics Publishers. 79 79