What is patient monitoring?

Patient monitoring is a series of repeated or continuous observations and documentation of the patient’s physiologic state and response to dialysis. Machine monitoring is continuous and includes the following: arterial and venous pressures, blood flow rate, transmembrane pressure (TMP), ultrafiltrate removed, dialysate temperature, dialysate flow and conductivity, and remaining treatment time. Dialysis personnel are responsible for reading, documenting, and evaluating these parameters. Vital signs are measured at least every hour or more frequently in unstable patients or where facility policy dictates. Assessments determine the appropriate dialysis intervention to attain the goals of treatment.

What are dialysis treatment outcome standards?

The National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (KDOQI) provides guidelines with indicators for outcomes. Four different clinical practices guidelines—hemodialysis adequacy, peritoneal dialysis adequacy, treatment of anemia, and vascular access—are used to assess and improve the outcome of each dialysis. Other guidelines have been developed, including nutrition, dyslipidemia, bone disease, and hypertension. Additional guidelines for pediatrics have also been developed. (See Appendix A for additional information on NKF KDOQI.)

What are the different types of hemodialysis assessment?

Types of assessment include the following: physical assessments, laboratory data analysis and interpretation, first dialysis assessment, intradialytic assessment (predialysis, postdialysis, and monitoring of hemodialysis procedure), and the interdisciplinary team (IDT) assessment using the Centers for Medicare & Medicaid Services (CMS) clinical practice guidelines. The IDT must develop and implement a written and individualized comprehensive plan of care. The plan of care should reflect changes in the patient’s condition and must include measurable and expected outcomes within a defined time frame.

What does physical assessment include?

Physical assessment consists of the following: assessing weight, blood pressure (BP), temperature, pulse, and respiratory rate; evaluating respiratory effort and extent of edema; auscultating for quality of heart sounds and breath sounds; comparing apical and peripheral pulses; assessing skin integrity, skin color, and jugular vein distension (JVD); and evaluating vascular access.

When are patients weighed?

Dialysis patients are weighed before and after each dialysis treatment. Some patients follow their weights at home to guide the adjustment of their fluid intake between dialyses.

Why is measurement of weight important?

Weight is a good indicator of how well the patient is controlling fluid balance between dialyses. Predialysis weight indicates how much ultrafiltration (UF) is required during the treatment. Postdialysis weight is the best indication of how much UF occurred during the hemodialysis procedure.

What is meant by the patient’s dry weight?

Dry weight is the ideal postdialysis weight after the removal of all or most excess body fluid. Patients who are at dry weight are usually normotensive. If the postdialysis weight suggests that volume status is too high, the patient may be on the borderline for fluid overload and may be hypertensive. If postdialysis weight is too low, the patient may be hypovolemic and at risk for hypotension and clotting of the vascular access.

How much weight gain is permissible between dialysis treatments?

Weight gained between dialysis procedures is due to fluid retention. Most dialysis units encourage patients to limit their weight gain to 0.5 kg (or 1 lb) per day. (Refer to Chapter 14 for further discussion and calculation of fluid restrictions.)

Why is blood pressure measurement important?

Blood pressure is often volume related. Hypertension may indicate volume overload. Hypotension may indicate dehydration. Blood pressure is measured while the patient is sitting and standing to evaluate orthostatic changes requiring intervention. It is important to monitor and treat hypertension in the patient with chronic kidney disease (CKD) to reduce the risk of cardiovascular disease and other complications. Hypertension occurs in more than 80% of patients with CKD stage 5.

What is normal blood pressure?

Hypertension is very common in CKD and as many as 75% of patients with a glomerular filtration rate (GFR) < 60 mL/min have a BP > 140/90 mm Hg. Normal BP is an individual matter. In the CKD patient, BP is analyzed for trends rather than absolute values. The KDOQI 2003 Guidelines on Goals of Antihypertensive Therapy for CKD recommend a target BP of < 130/80 mm Hg.

Where can the cuff be placed for blood pressure measurement?

The upper arm is the most common cuff placement site but there are two alternative placements. A large thigh cuff can be applied around the midthigh area. The pulse is audible via a stethoscope at the popliteal space. As well, a regular cuff may be applied above the ankle with auscultation over the posterior tibial or dorsalis pedis artery. This usually yields an audible BP, but the readings obtained will be 20 to 40 mm Hg higher than arm pressures. A notation should be made on the patient’s chart whenever leg pressures are taken. Blood pressure cuffs should never be placed on an extremity with a deep vein thrombosis, grafts, ischemic changes, or AV fistula or graft.

Why are temperature, pulse, and respiration monitored?

Temperature, pulse, and respiration (TPR) observations serve as a baseline at the start of dialysis. Temperature elevation suggests infection or complicating illness. An elevated temperature is often a sign of vascular access infection. Fever during dialysis may be caused by high dialysate temperature or by a pyrogen reaction. A rapid pulse may result from anemia or fluid overload. Irregular heart rate (arrhythmia) may indicate cardiac complications, including those associated with serum potassium levels. An increase in pulse rate during dialysis may be associated with falling blood volume (from UF) and may occur just before a drop in BP. Increased respiratory rate may indicate excessive fluid gain. Any unexpected findings should be reported to the physician.

What is edema?

Edema is the excessive accumulation of fluid in the tissue spaces. Excessive weight gain between dialyses results in edema. Edema appears in different areas of the body in different patients. It may present at the ankle or sacrum, facial or periorbital areas, or peripherally. The jugular veins are often distended when the patient is fluid overloaded. Fluid status assessment determines the amount of UF required during dialysis.

Are there other physical assessments?

The predialysis assessment includes a subjective analysis of the patient’s health since the previous dialysis treatment. Ask whether the patient has experienced such symptoms as headaches, hypotension, bleeding, or diarrhea. Dialysis personnel can assess changes in mentation, speech, or thought processes while patients describe their health and any problems between dialysis sessions.

Why is the first hemodialysis procedure so important?

The first hemodialysis is critical because it sets the atmosphere for all future treatment procedures. The first dialysis is sometimes performed in the hospital. The patient may be unstable and feel sick. The information the nurse gives the patient during this first dialysis is often forgotten or misunderstood. Therefore the nurse and dialysis personnel must reiterate teaching instructions regarding medications or access care again and again. Written manuals and instructions are helpful so that patients have a reference as needed. Sometimes the first dialysis is performed in an outpatient dialysis facility. When this is the case, it is imperative that the dialysis personnel be cognizant of the emotional status of the new patient. The patient may be fearful because of the myths about dialysis he or she has heard, or because of the equipment’s appearance. These fears, combined with the fact that the patient is chronically ill, are strong reasons for the patient to be in emotional shock and to not recall instructions given during the first dialysis. The dialysis nurse and personnel must make the first dialysis as smooth and uneventful as possible.

What procedures take place before the first hemodialysis?

The physician evaluates and prescribes the dialysis orders for the new patient. The nurse reviews the orders and, after the fluid composition and machine settings are programmed, starts predialysis assessment. Before the first meeting with the patient, medical records should be reviewed. This information will be helpful during the physical assessment. After introductions, a brief tour around the facility should be conducted. The first visit should be as simple and as pleasant as possible. Remember that instructions will have to be repeated many times.

Make certain that a signed consent for the dialysis treatment is completed and retained in the patient’s medical records. The physical assessment begins with the patient’s weight, BP, temperature, pulse, and respiratory rate. A general assessment of the patient’s fluid status and overall well-being follows. Some questions that should be asked include the following: Is there edema? Is the patient in any respiratory distress or experiencing any pain? Is there any bleeding or bruising? Is there residual renal function? Are bowel movements regular? Are there sleep problems? Many units have assessment forms that offer guidelines to the caregiver.

During this first procedure some of the dialysis parameters will be set: for example, heparin requirements, tolerance of fluid removal, arterial and venous pressure readings, saline requirements, tolerance to the dialyzer, and the dialysate composition. Because the first dialysis is so critical, the physician usually prescribes a slow blood flow and only two hours of dialysis.

What is predialysis assessment?

Before initiation of hemodialysis, the patient and machine are both evaluated. The patient’s physiologic status is assessed to ascertain the need to adjust dialysis orders or prescribed medications. The machine parameters are assessed to ensure that the prescribed procedure is implemented correctly.

What is included in the patient’s predialysis assessment?

Predialysis assessment includes the following:

What other checks should be done on the dialysis machine before patient use?

It is necessary to ensure that machine functions have been checked and that they work correctly. All extracorporeal alarms should be tested to ensure that they respond appropriately. Arterial pressure, venous pressure, and air detector alarms should all cause the blood pump to stop and the venous line clamp to close. In addition, conductivity and temperature of the dialysate should be tested to ensure that they are within the proper range. These alarms must be working at all times so that, if any problems arise, the dialysate will be diverted from the dialyzer and a major complication will be avoided. Finally, there should be an adequate amount of dialysate concentrate to complete the patient’s treatment.

What is included in machine preassessment?

Machine preassessment includes the following:

What is sodium modeling or sodium variation, and when is it applicable?

During dialysis small solutes, primarily urea, are removed from the extracellular fluid (ECF), resulting in a fall in ECF osmolality. This fall in ECF osmolality causes a shift of water into cells, aggravating hypotension. One way of preventing this phenomenon is by replacing the lost osmoles (urea) with sodium. This can be done automatically by the dialysis machine and may prevent or minimize hypotension.

Sodium variations allow the dialysis treatment to be modified by increasing the concentrate-to-water ratio slightly, resulting in a rise in dialysate sodium. This feature allows the dialysis staff to initiate hemodialysis with a high-dialysate sodium concentration and use progressively lower sodium-containing dialysate, decreasing to the original baseline level in a programmed time and profile. These maneuvers are intended to reduce the incidence of hypotension and cramping. By varying the level of sodium in the dialysate, the drop in osmolality of the patient’s serum is more gradual. The fluid that is in the interstitial spaces in the tissues does not transfer into the vascular spaces as fast as the dialysis machine is able to remove it. The result of this is fluid depletion of the vascular space and the resultant side effects of hypotension. The sodium variation system keeps the vascular space filled enough to prevent this fluid depletion from occurring. There are several machines available to perform this treatment function. The Fresenius 2008H has three sodium variation system profiles: step decrease, linear decrease, and exponential decrease. Fig. 13-1 illustrates these system profiles. The baseline is determined by the basic setting of the mechanical acid/acetate and bicarbonate concentrate pumps. With this method of sodium modeling there is a significant variation in the dialysate potassium level. If the dialysate sodium is increased from 140 to 160 mEq/L (about 14%), the dialysate potassium concentration will also increase by 14%. If the baseline concentrate has 3 mEq/L of potassium and is increased by 14%, the new potassium concentrate would be 3.4 mEq/L. If there is a decrease in the dialysate sodium to 120 mEq/L (decrease of 14%), the new potassium concentrate will be 2.6 mEq/L. Increasing sodium in the dialysate has assisted many patients in the prevention of hypotension, cramping, and disequilibrium syndrome during dialysis. The physician writes the orders for the sodium modeling for each patient.

Figure 13-1 Sodium variation system profiles. The exponential program causes the conductivity to decrease toward the baseline over the programmed time in a smooth curve. The linear program is a straight-line reduction from the program maximum to the baseline level. The step program allows for a single large step to be performed.

(From Gotch FA, et al: Measurement of whole body UF on urea mass transfer coefficients: implications for Na+ urea modeling in dialysis, Presentation at the American Society of Nurses, 1984.)

Are there complications of sodium modeling?

Some patients experience increased interdialytic thirst, weight gain, and BP when sodium modeling is used. Adjustment of the dialysate sodium concentration may be required.

Why is it necessary to do such a thorough assessment of the patient and the machine before initiation of the dialysis treatment?

The accuracy of assessment and the appropriateness of the interventions directly affect the patient’s outcome and will ensure that the goal of adequacy of dialysis is achieved.

What is ultrafiltration?

UF is the removal of fluid during dialysis. It is the result of hydrostatic force across the dialysis membrane. The difference in hydrostatic pressure, blood to fluid, is the TMP. The rate of UF is the sum total of positive and negative pressures plus the filtration factor, known as the UF coefficient (k_UF), of each individual dialyzer. The k_UF ranges from 0.5 to 80.0 mL/h/mm Hg, depending on specific dialyzer characteristics (see Chapter 6).