119 Continuous Renal Replacement Therapies - Elsevier

1054

Unit V Renal System

PROCEDURE

119

Continuous Renal Replacement Therapies Sonia M. Astle

PURPOSE: Continuous renal replacement therapies are used in the critical care unit setting for volume regulation, acid-base control, electrolyte regulation, drug intoxications, management of azotemia, and immune modulation. These methods are most often used in critically ill patients whose hemodynamic status does not tolerate the rapid fl uid and electrolyte shifts associated with intermittent hemodialysis or who need continuous removal or regulation of solutes and intravascular volume.

Section Seventeen Renal Replacement

PREREQUISITE NURSING KNOWLEDGE

• Continuous renal replacement therapy (CRRT) is an extra-corporeal blood-purifi cation therapy intended to substitute for impaired renal function over an extended period of time for, or attempted for, 24 hours per day. 1

• CRRT can be accomplished through a variety of methods, with either arteriovenous (AV) access or venovenous (VV) access. The VV access is used almost exclusively because of its less invasive nature. In the past, AV access was used, requiring both arterial and venous cannulation. With AV access, the patient ’ s systemic blood pressure is required for blood to fl ow into the extracorporeal circuit, making it unreliable for hypotensive patients. The newer-generation CRRT machines have an added extracorporeal blood pump that pulls the patient ’ s blood into the circuit, so it is better suited to treat hemodynamically unstable patients. 10,18

• The following methods of CRRT are included as listed (details are outlined in Table 119-1 ): ❖ Slow, continuous ultrafi ltration (SCUF) ❖ Continuous venovenous hemofi ltration (CVVH) ❖ Continuous venovenous hemodialysis (CVVHD) ❖ Continuous venovenous hemodiafi ltration (CVVHDF)

• Basic knowledge is required to understand the principles of diffusion, ultrafi ltration (UF), osmosis, oncotic pres-sure, and hydrostatic pressure and how they pertain to fl uid and solute management during dialysis. ❖ Diffusion: The passive movement of solutes through a

semipermeable membrane from an area of higher to lower concentration until equilibrium is reached.

❖ Convective transport: The rapid movement of fl uid across a semipermeable membrane from an area of

high pressure to an area of low pressure with transport of solutes. When water moves across a membrane along a pressure gradient, some solutes are carried along with the water and do not require a solute con-centration gradient (also called solute drag). Convec-tive transport is most effective for the removal of middle-molecular-weight and large-molecular-weight solutes.

❖ UF: The bulk movement of solute and solvent through a semipermeable membrane in response to a pressure difference across the membrane. This movement is usually achieved with positive pressure in the blood compartment in the hemofi lter and negative pressure in the dialysate compartment. Blood and dialysate run countercurrent. The size of the solute molecules com-pared with the size of molecules that can move through the semipermeable membrane determines the degree of UF.

❖ Osmosis: The passive movement of solvent through a semipermeable membrane from an area of higher to lower concentration.

❖ Oncotic pressure: The pressure exerted by plasma proteins that favor intravascular fl uid retention and movement of fl uid from the extravascular to the intra-vascular space.

❖ Hydrostatic pressure: The force exerted by arterial blood pressure that favors the movement of fl uid from the intravascular to the extravascular space.

❖ Absorption: The process by which drug molecules pass through membranes and fl uid barriers and into body fl uids.

❖ Adsorption: The adhesion of molecules (solutes) to the surface of the hemofi lter, charcoal, or resin.

• CRRT uses an artifi cial kidney (i.e., hemofi lter, dialyzer) with a semipermeable membrane to create two separate

119 Continuous Renal Replacement Therapies 1055

Adapted from Giuliano K, Pysznik E: Renal replacement therapy in critical care: implementation of a unit-based CVVH program, Crit Care Nurse 18:40–45, 1998.

Ultrafi ltration Mode of Therapies

Principles Involved Access Indications Advantages

Complications/Disadvantages

SCUF (slow, continuous ultrafi ltration)

Ultrafi ltration Venovenous Patients with diuretic-resistant, volume-overloaded, hemodynamically unstable conditions who cannot tolerate rapid fl uid shifts

Continuous, gradual treatment (fewer high and low extremes)

Precise fl uid control can be done in patient with low mean arterial pressure

Anticoagulation, bleeding Hypotension Hypothermia Access complications (bleeding,

clotting, infection) Requires strict monitoring of

fl uid and electrolyte replacement to avoid defi cits or overload

Air embolism Critical care setting only Poor control of azotemia;

dialysis may be needed Minimal solute clearance Not recommended for

emergently treating hyperkalemia or acidosis

CVVH (continuous venovenous hemofi ltration)

Ultrafi ltration Convection Solute removal

Venovenous Patient with volume-overloaded, hemodynamically unstable condition with azotemia or uremia

Precise fl uid control can be done in patients with low mean arterial pressure

Ease of initiation

Anticoagulation, bleeding Hypotension Hypothermia Access complications (bleeding,

clotting, infection) Requires strict monitoring of

fl uid and electrolyte replacement to avoid defi cits or overload

Air embolism Critical care setting only Recommended 1 : 1 nurse/

patient ratio Metabolite removal not as

effi cient as CVVHDF

CVVHD (continuous venovenous hemodialysis)

Ultrafi ltration Diffusion Solute removal

Venovenous Patients with volume-overloaded, hemodynamically unstable conditions with azotemia or uremia

Precise fl uid control can be done in patients with low mean arterial pressure

Ease of initiation

Same as CVVH Hyperglycemia Hypernatremia Hypophosphatemia

CVVHDF (continuous venovenous hemodiafi ltration)

Ultrafi ltration Convection Diffusion Solute removal

Venovenous Patient with volume-overloaded, hemodynamically unstable conditions with azotemia or uremia, catabolic acute renal failure, electrolyte imbalances/metabolic acidosis

Precise fl uid control can be done in patient with low mean arterial pressure

Better solute clearance than CVVH/ CVVHD

Ease of initiation

Same as CVVH Hyperglycemia Hypernatremia Hypophosphatemia

TABLE 119-1 Continuous Renal Replacement Therapies

compartments: the blood compartment and the dialysis solution compartment. The semipermeable membrane allows the movement of small molecules (e.g., electro-lytes) and middle-size molecules (e.g., creatinine, vasoac-tive substances) from the patient ’ s blood into the dialysis

solution but is impermeable to larger molecules (e.g., red blood cells, plasma proteins).

• Each dialyzer has four ports: two end ports for blood (blood fl ows in one end and out the other) and two side ports for dialysis solution ultrafi ltrate (dialysate solution

1056 Unit V Renal System

fl ows in one end and out the other). In most cases, the blood and dialysate run through the dialyzer in opposite or countercurrent directions.

• Hollow-fi ber dialyzers are used almost exclusively for CRRT. The blood fl ows through the center of hollow fi bers, and the dialysis solution (dialysate) fl ows around the outside of the hollow fi bers. The advantages of hollow-fi ber fi lters include a low priming volume, a low resis-tance to fl ow, and a high amount of surface area. The major disadvantage is the potential for clotting as a result of the small fi ber size.

• All dialyzers have a UF coeffi cient; thus, the dialyzer selected varies in different clinical situations. 2–6,8,9 The higher the UF coeffi cient, the more rapid the fl uid removal. 12,16,19 UF coeffi cients are determined with in vivo measurements done by each dialyzer manufacturer.

• Clearance refers to the ability of the dialyzer to remove metabolic waste products or drugs from the patient ’ s blood. The blood fl ow rate, the dialysate fl ow rate, and the solute concentration affect clearance. Clearance occurs by the processes of diffusion, convection, and UF.

• The dialysate (when used during CRRT) is composed of water, a buffer (i.e., lactate or bicarbonate), and various electrolytes. Most solutions also contain glucose. The buffer helps neutralize acids that are generated as a result of normal cellular metabolism. The concentration of elec-trolytes is usually the normal plasma concentration, which helps to create a concentration gradient for removal of excess electrolytes. The glucose aids in increasing the oncotic pressure in the dialysate (thus aiding in fl uid removal) and in caloric replacement. Although glucose comes in various concentrations, it is usually used in normal plasma concentrations to prevent hyperglycemia.

• Heparin or citrate are often used during CRRT to prevent clotting of the extracorporeal circuit during treatment. Saline solution fl ushes can be used alone or with other anticoagulants to maintain circuit patency. 31,33

• An anticoagulant may be used to maintain vascular access patency when CRRT is not in use. 4,18,33

• If the patient is taking angiotensin-converting enzyme (ACE) inhibitors, contact with certain fi lters or mem-branes in the CRRT system can cause an anaphylactic reaction and severe hypotension as a result of increased levels of bradykinin, a potent vasodilator. 15 ACE inhibi-tors are recommended to be withheld for 48 to 72 hours before treatment, if possible.

• Continuous venovenous renal replacement therapy is achieved with a pumped system.

• The patient ’ s volume status and serum electrolyte levels are changed gradually so that patients have fewer prob-lems maintaining hemodynamic stability than with hemo-dialysis. Specifi cs of these therapies are outlined in Table 119-1 . 1,3,6,10,22–24,28,29

• SCUF ( Fig. 119-1 ) is a nonpumped system; CVVH ( Fig. 119-2 ), CVVHD ( Fig. 119-3 ), and CVVHDF ( Fig. 119-4 ) use pump-driven systems. These therapies are used to remove both plasma water and solutes and require venous access, most commonly provided with a double-lumen vascular access catheter (VAC). Hemodialysis shunts or surgically created hemodialysis anastomoses have been

Figure 119-1 Slow continuous ultrafi ltration (SCUF). Fluid removal, no fl uid replacement. (Copyright Rhonda K. Martin. All rights reserved. Used with permission.)

UF drain bag

Figure 119-2 Continuous venovenous hemofi ltration (CVVH). Fluid removal and fl uid replacement. (Copyright Rhonda K. Martin. All rights reserved. Used with permission.)

UF drain bag

Blood pump

Replacement fluid

used in the past for CRRT; however, because of increased incidence rates of vascular injury, bleeding, and infection, they are not recommended for CRRT access. 1,18 Common sites for the VAC are the internal jugular, subclavian, and femoral veins. The internal jugular approach is the pre-ferred access. Cannulation of the subclavian vein may cause stenosis and prevent placement of upper extremity grafts or fi stulas if long-term dialysis is necessary. 4,25,28 Femoral cannulation is associated with increased infection. 4,16,32

• A blood pump provides the pressure that drives the extra-corporeal system; the blood circuit consists of blood lines, a blood pump, and various monitoring devices. The blood lines are connected to the vascular access and carry the blood to and from the patient. The blood pump controls the speed of the blood through the circuit. The monitoring


The module calculates and adjusts pump speeds to achieve the selected fl uid goal. The module also records and displays treatment data.

• SCUF (see Fig. 119-1 ) is used primarily to remove plasma water. A hemofi lter with a large surface area, high sieving coeffi cient, and low resistance is used to facilitate slow continuous fl uid removal.

• CVVH (see Fig. 119-2 ) removes fl uids and solutes via convective clearance. Replacement solution is part of the setup; the replacement solution creates a solute drag effect.

• CVVHD (see Fig. 119-3 ) is used to remove solutes pri-marily via diffusion. Dialysate solution is part of the setup; fl ow of the dialysate is countercurrent to the blood fl ow.

• CVVHDF (see Fig. 119-4 ) removes fl uids and solutes via diffusion and convection. Dialysate runs countercurrent to the blood fl ow and clears toxins by diffusion. Replace-ment fl uid is infused at a prescribed rate and clears by convection.

• Other extended renal replacement therapy techniques or “hybrid” techniques (sustained low-effi ciency dialysis, extended daily dialysis) generally use standard hemodi-alysis equipment with reduced blood fl ow and dialysate rates to gradually remove plasma water and solutes. They are used from 4 to 12 hours a day. 26

EQUIPMENT

• Dedicated vascular access • Hemofi lter/pump system with blood lines

devices include arterial and venous pressure monitors and an air detection monitor to prevent air that may have entered the circuit from being infused to the patient. Anti-coagulant, dialysate, and replacement fl uids can also be added to the system. ❖ Integrated pump systems have separate pumps for

blood, dialysate, ultrafi ltrate/effl uent, and replacement fl uids ( Fig. 119-5 ). The pumps are controlled by a computerized control module. Blood fl ow rate, dialy-sate fl ow rate, anticoagulation rate, and fl uid-removal rates are entered by the nurse as prescribed. Dialysate, ultrafi ltrate/effl uent, and replacement fl uids are mea-sured by weight or volumetric scales on the machine.

Figure 119-3 Continuous venovenous hemodialysis (CVVHD). Fluid and solute removal with dialysate. (Copyright Rhonda K. Martin. All rights reserved. Used with permission.)

Blood pump

UF drain bag

Dialysate

Figure 119-4 Continuous venovenous hemodiafi ltration (CVVHDF). Fluid replacement with dialysate. (Copyright Rhonda K. Martin. All rights reserved. Used with permission.)

UF drain bag

Blood pump

Dialysate

Replacement fluid Figure 119-5 Gambro Prismafl ex Continuous renal replacement therapy machine. (Courtesy Gambro USA, Lakewood, Colo.)


PATIENT ASSESSMENT AND PREPARATION Patient Assessment • Assess baseline vital signs, including hemodynamic

parameters, weight, current medications, laboratory values (blood urea nitrogen, creatinine, electrolytes, hemoglobin, and hematocrit), neurological status, and nutritional needs. 7,11,17,27 Rationale: Patients in renal failure often have altered baseline assessment results, both in physical assessment and in laboratory values. Knowledge of this information before treatments are started is helpful so that interventions, including net fl uid balance and dialysate fl uid, can be individualized. Alterations during treatment are common because of the rapid removal of fl uid and solutes.

• Assess the VAC insertion site for signs and symptoms of infection. Rationale: Insertion sites provide a portal of entry for organisms, which may result in septicemia if unrecognized or untreated. If the insertion site appears to be infected, further interventions (e.g., site change, culture, antibiotic treatment) may be necessary.

• Assess the patency of the VAC and the ability to easily aspirate blood from both ports. Rationale: Adequate blood fl ow is necessary during treatment to facilitate optimal fl uid and solute removal. Patent catheter ports are necessary for adequate blood fl ow.

• Assess adequate circulation to the distal parts of the access limb. Rationale: The placement of vascular access may compromise circulation.

Patient Preparation • Verify that the patient is the correct patient using two

identifi ers. Rationale: Before performing a procedure, the nurse should ensure the correct identifi cation of the patient for the intended intervention.

• When CRRT is initiated, ensure that informed consent has been obtained. Rationale: Informed consent protects the rights of the patient.

• Ensure the patient understands preprocedural teachings. Answer questions as they arise, and reinforce information as needed. Rationale: Understanding of previously taught information is evaluated and reinforced.

• Position the patient in a comfortable position (that also facilitates optimal blood fl ow through the vascular access). Rationale: The patient and family must understand that movement may affect blood fl ow through the system and that a comfortable position is important.

• Following initiation of treatment, continue to reposition the patient at regular intervals. Rationale: Critically ill patients are at a high risk for pressure points and skin breakdown.

• Replacement fl uid as prescribed • Dialysate fl uid as prescribed • Fluid shield, face masks, or goggles • Sterile and nonsterile gloves • Fluid warmer • Two 10-mL prefi lled syringes with normal saline (NS)

solution • Sterile NS solution, 1 to 2 L • Dressing supplies (alcohol wipes, sterile barrier, gauze

pads, transparent dressing, tape) • Antiseptic solution (e.g., 2% chlorhexidine–based

preparation) • Heparin, 1000 units/mL, or citrate (for priming, as

prescribed) • Drainage bag • Intravenous (IV) accessory spike to connect NS bag to

arterial tubing • Two dialysis luer caps for the VAC Additional equipment, to have available as needed, includes the following: • Two 5-mL syringes and blunt-tip needles (if needed to

draw up NS for injection) • NS for injection (if prefi lled NS syringes are not used) • Plastic hemodialysis clamps

PATIENT AND FAMILY EDUCATION

• Explain the purpose of CRRT—specifi cally why the treat-ment is performed and the expected clinical outcomes. Rationale: The patient and family should understand that CRRT is necessary to perform the physiological func-tions of the kidneys if the patient is hemodynamically unstable.

• Explain the procedure, including risks, anticipated length of treatment, and patient positioning, and review any questions the patient may have. Rationale: Explanation provides information and may decrease patient anxiety.

• Explain the need for careful sterile technique for the dura-tion of treatment. Rationale: The patient and family must know the importance of sterile technique to decrease the likelihood of systemic infection.

• Explain the need for careful monitoring of the patient during the treatment, particularly for fl uid and electrolyte imbalance. Rationale: The patient and family should understand that careful monitoring is a routine part of CRRT.

• Explain the signs and symptoms of possible complications during CRRT. Rationale: Patients and family should be fully prepared if complications occur (e.g., hypotension, hemorrhage, manifestations of fl uid/electrolyte/acid-base imbalance).

• Explain the CRRT circuit setup to the patient and family. Rationale: It is important that the patient and family know that blood will be removed from the patient ’ s body and will be visible during the CRRT treatment.


Steps Rationale Special Considerations

Systems (SCUF, CVVH, CVVHD, CVVHDF) 1. HH 2. PE 3. Verify orders, which should

include the following: A. Modality B. Vascular access C. Type of hemofi lter/dialyzer D. Anticoagulant type,

concentration, infusion rate, monitoring parameters

E. Replacement fl uid and rate (if used)

F. Hourly ultrafi ltration UF rate G. Hourly net fl uid goal H. Dialysate solution and rate

(if used) I. Blood pressure/vital sign

parameters J. Laboratory testing

Familiarizes the nurse with the individualized patient treatment and reduces the possibility of error. 4,6

Ensure patient weight and laboratory values are assessed and recorded before initiation of therapy. Communicate with the nephrologist/intensivist ordering therapy if questions arise. 14,30

4. Prepare the system: A. Turn the machine on. B. Load the circuit according to

the manufacturer ’ s instructions.

C. Attach solutions as prescribed. D. Prepare anticoagulant infusion

as prescribed. E. Prepare replacement fl uid,

dialysate, and fl ush infusion as prescribed.

F. For integrated pump units follow the manufacturer ’ s instructions and prompts from the control screen.

G. Automated setup instructions include: 1. Select therapy/modality. 2. Calibration (if indicated). 3. Load set. 4. Priming. 5. Anticoagulant. 6. Dialysate and replacement

fl uid rates. 7. Blood fl ow. rate 8. Fluid removal rate.

H. After priming per manufacturer instructions, go to Step 5.

Correct system setup is imperative for safety and optimal functioning. The use of anticoagulants prolongs the function of the hemofi lter. 4,6

The pump must be plugged into a generator outlet because some pumps do not have battery power. Heparin, if ordered, is usually administered on a prefi lter port; citrate is usually administered at the arterial port of the VAC or infused via the preblood pump. Replacement solutions are administered through the arterial (access) or venous (return) infusion port as ordered (usually arterial) with blood tubing. Connect 1 L NS to arterial infusion port (for fl ushing system). Dialysate solution (if CVVHD/CVVHDF are used) is connected to the outlet port of the hemofi lter near the venous end with blood tubing. Each integrated pump is loaded and primed according to the manufacturer ’ s recommendations, ranging from assembly and priming of all components to “one-touch” circuit loading and priming. Some unit ’ s air detectors are activated after the machine is primed.

5. Leave the priming bag, collection bag, and protective caps in place until the blood lines are attached to the VAC.

Preserves the sterility of the system. Some systems have a collection bag for the priming solution, which stays attached to the venous blood line until it is attached to the VAC.

6. Remove gloves and discard in the appropriate receptacles.

Reduces transmission of microorganisms; Standard Precautions.

Procedure for Initiation and Termination of Continuous Renal Replacement Therapy

Procedure continues on following page



7. Wash hands. Reduces transmission of microorganisms on the hands after removal of gloves and before performing a sterile procedure.

8. Prepare a sterile fi eld with sterile barrier under the VAC.

Prepares material and maintains aseptic technique.

9. Place 4 × 4 gauze pads onto the sterile fi eld. Open sterile container, syringes, blunt-tip needles, and NS (or prefi lled NS syringes) and place on the sterile fi eld.

Prepares material and maintains aseptic technique.

10. Add antiseptic solution (e.g., 2% chlorhexidine–based preparation) to sterile container or use prepackaged bactericidal agents. (Level D * )

Prepares solution used to cleanse VAC ports. Povidone-iodine, hypochlorite, and chlorhexidine solutions are acceptable bactericidal agents. 4,18,31

11. Wash hands and apply sterile gloves.

Maintains aseptic technique.

12. Attach blunt-tip needles to two 10-mL syringes; with help of assistant, fi ll with NS or use prefi lled syringes per institutional standards.

Prepares syringe for VAC fl ushing. With Quinton catheters, a 20–30 mL per lumen fl ush for hemocaths and permacaths is recommended. 1

13. Saturate four of the 4 × 4 pads in the antiseptic solution. Using two of the soaked pads, perform a 1-minute scrub of the arterial and venous ports of the VAC. Alternatively, perform a 30-second scrub of the ports with antiseptic swabs.

Prevents introduction of pathogens. Be sure to remove any crust or drainage at the catheter insertion site.

14. Ensure clamps are closed on the arterial and venous ports of the VAC; then remove the cap from the arterial port of the VAC and discard. Alternatively, many facilities are using dialysis-specifi c luer caps that lock into the VAC.

Provides access to the arterial side of the VAC. The VAC is not opened to air unless caps require changing, reducing the chance of contamination and infection.

Be sure the VAC clamp is closed before removing arterial and venous port caps.

15. Attach an empty 5-mL syringe to the arterial port, open the clamp, and gently aspirate 5 mL of blood and anticoagulant. Close the clamp, remove the syringe, and discard it in an appropriate receptacle.

Verifi es the patency of the arterial port. Note any resistance, which may indicate a clotted or kinked port. Prevents bolus of anticoagulant to the patient (if used) and decreases transmission of microorganisms. 4,18

Do not forward-fl ush an indwelling port before aspirating. This prevents dislodgment/embolism of clots and prevents a bolus of anticoagulant to the patient. Observe for clots. A clotted or kinked port decreases blood fl ow and reduces effi cacy of the treatment.

16. Attach a 10-mL syringe with NS fl ush solution to the arterial port. Open the clamp and fl ush; then close the clamp.

Prevents clotting of blood until dialysis is initiated.

Note any resistance on fl ushing.

Procedure for Initiation and Termination of Continuous Renal Replacement Therapy—Continued

* Level D: Peer-reviewed professional and organizational standards with the support of clinical study recommen dations.




17. Repeat Steps 15–16 on the venous port.

Provides access to the venous side of the catheter.

18. Disconnect the access line from the primed circuit and attach it to the arterial port of the VAC; secure the connection.

Loose connections introduce air into the circuit.

19. Disconnect the return line from the primed circuit and attach it to the venous port of the VAC; secure the connection.

Loose connections introduce air into the circuit.

20. Open the clamps on the VAC ports and the access and return blood lines.

Opens the circuit in preparation for starting the blood pump.

Perform a fi nal check for air in the circuit.

21. Check that all alarms are on and parameters are set.

Ensures safe delivery of therapy.

22. Turn the blood pump on and gradually increase the blood fl ow to the prescribed rate.

Prevents hypotension from rapid blood and fl uid shifts.

Observe for blood leaks, air in the system, and pressure alarms. Assess the patient ’ s vital signs, which should remain within 20% of baseline parameters.

23. Note blood pump fl ow rate, arterial and venous monitor pressures, transmembrane (TMP) fi lter pressure, the amount and color of UF, and vital signs on initiation and hourly or per institutional standards.

Ensures safe delivery of therapy. Increased arterial pressure indicates problems with the vascular access or blood infl ow. Increased venous pressure indicates clotting of the system. Decreased venous pressure indicates clotting of the hemofi lter.

24. Remove PE and discard supplies in the appropriate receptacles.

Safely discards used supplies.

25. HH 26. Prepare a fl uid balance fl ow sheet

and calculate the net fl uid gain/loss prescribed each hour or document in the electronic health record.

Accurate calculations of hourly fl uid balance prevent hypervolemia and hypovolemia and ensure that clinical goals are being met.

Hourly fl uid balance is usually calculated by subtracting the total output (including UF removed) from the total intake.

Flushing 1. HH 2. PE 3. Connect the NS with primed

tubing to the arterial port of the VAC and the access line of the circuit via a three-way stopcock.

Prepares port for fl ushing.

4. Clamp the arterial port of the VAC by turning the stopcock off to the VAC port.

Prevents any more blood from entering the circuit via the arterial port during fl ushing.

Note: Be sure that the NS fl ush is running freely to prevent rupture or back fi ltration. Hemostasis and clot formation in the arterial limb of the tubing are possibilities if the fl ushing procedure is prolonged.

5. Open the NS fl ush while the pump continues to run. Note the amount of NS that has infused.

Flushing allows the nurse to assess the patency of the system. 3

Flushing contributes to the patient ’ s IV intake; the volume of fl uid should be documented. When the circuit is fl ushed of blood, clots may be observed. Flushing does not dissolve existing clots.




6. If clots are not observed, turn off the NS by moving the stopcock “off” to the NS fl ush and open to the arterial port of the VAC.

Continues therapy. If numerous clots are observed, the hemofi lter may need to be replaced. Heparin will not dissolve existing clots.

7. Remove PE and discard used equipment in appropriate receptacles.


8. HH Termination 1. HH 2. PE 3. Turn off all infusions into the

circuit. Prepares for termination of therapy.

4. With the IV accessory spike, attach the NS fl ush solution to the arterial infusion line of the circuit. If using NS fl ushes, this line can be used to fl ush the circuit when terminating the treatment.

Prepares for fl ushing blood from the tubing.

5. Return the blood in the circuit to the patient. When the entire circuit is clear of blood, turn off the pump and clamp off both the arterial and venous lines.

Follow instructions on the pump for termination. The blood should be fl ushed from the circuit back to the patient to prevent unnecessary blood loss.

If clots are identifi ed beyond the venous bubble trap, stop the pump; do not return blood to the patient.

6. Continue terminating the procedure according to the manufacturer ’ s guidelines.

7. If the VAC is to be discontinued, remove it per institutional guidelines.

CRRT therapy may no longer be needed.

8. Record the amount of NS infused.

Ensures accurate fl uid balance. The fl ush solution infused to the patient must be recorded as intake.

9. If the VAC is not to be removed, prepare the sterile fi eld. Open and place the sterile barrier under the VAC.


10. Place 4 × 4 gauze pads onto the sterile fi eld. Open the sterile container, syringes, blunt-tip needles, and NS (or prefi lled NS syringes) and place them on the sterile fi eld.


11. Add antiseptic solution (e.g., 2% chlorhexidine–based preparation) to the sterile container (or use prepackaged bacterial solution). (Level D * )

Prepares solution used to cleanse VAC ports. Povidone-iodine, hypochlorite and chlorhexidine solutions are acceptable bactericidal agents. 3,10,19

12. Remove gloves and discard in appropriate receptacles.


13. Wash hands. 14. Don sterile gloves.


*Level D: Peer-reviewed professional and organizational standards with the support of clinical study recommen dations.




15. Attach blunt-tip needles to two 10-mL syringes; with the help of an assistant, fi ll the syringes with NS or use prefi lled syringes per institutional standards.

Prepares the syringe for VAC fl ushing.

A 20–30 mL per lumen fl ush is recommended. 1

16. Saturate two 4 × 4 gauze pads in antiseptic solution. Perform a 1-minute scrub of the arterial and venous ports of the VAC. Alternatively, perform a 30-second scrub of the ports with chlorhexidine swabs (if approved by the catheter ’ s manufacturer).

Prevents introduction of infection. Be sure to remove any crust or drainage.

17. Be sure clamps are closed on the arterial and venous ports of the VAC before disconnecting the arterial blood line from the arterial vascular access. Alternatively, if dialysis luer caps are used, the circuit lines can be disconnected without opening the VAC ports.

Opens the system under sterile conditions for system termination.

Be sure the port clamp is closed before removing the arterial line.

18. Repeat Step 18 on the venous system line.

19. Attach a 10-mL syringe with NS to the arterial port. Open the clamp and fl ush, then close the clamp.

Prevents clotting of blood until anticoagulant is instilled.

20. Repeat Step 20 on the venous port.

21. Instill the prescribed anticoagulant into each access port according to institutional standards. Use only the “fi ll” amount listed on the VAC ports to avoid instilling anticoagulant into the patient. (Many facilities are now using NS instead of heparin and dialysis-specifi c locking caps to prevent opening the VAC ports to air.)

Maintains patency of the accesses. Label each port with the date, time, and anticoagulant used, and your initials.

22. Clamp and cap the arterial and venous ports with the sterile needleless luer caps.

Maintains sterility of the VAC.

23. Change the vascular access dressings according to institutional guidelines.

Prevents infection.

24. Remove PE and discard used equipment in the appropriate receptacle.


25. HH



Expected Outcomes • VAC accessed without complications • Blood easily aspirated from the access site • Accumulated fl uid and waste products removed • Acid-base balance restored • Blood urea nitrogen and creatinine values restored to

baseline levels • Electrolyte levels within baseline values • Hemodynamic stability and maintenance of optimal

intravascular volume • Nutritional status maintained

Unexpected Outcomes • Clotting/decreased patency of the access sites • Crack in the VAC or end caps • Bleeding from the VAC insertion site or access/return

lines • Signs and symptoms of infection at the insertion or

access site • Dislodgment of the VAC • Decreased circulation in the extremity with the

vascular access • Hematoma formation at the VAC insertion site • Physiological complications (dysrhythmias, chest

pain, fl uid or electrolyte imbalance, complications related to anticoagulation, air embolism, hypotension, seizures, nausea and vomiting, headaches, muscle cramping, dyspnea, exsanguination, hemorrhage)

• Introduction of pathogens or air into the circuit • Technical problems with the blood pump (blood leak,

air leak, clotting, disconnection of circuit, hemolysis, hemofi lter rupture)

• Hypothermia 21 • Malnutrition

Patient Monitoring and Care Steps Rationale Reportable Conditions

These conditions should be reported if they persist despite interventions.

1. Obtain and record predialysis and daily weight.

Predialysis weight is an important factor in deciding how much UF is needed and helps guide ongoing treatment. 4

• Increase or decrease in weight

2. Perform ongoing assessments, including the following: A. Vital signs B. Jugular vein distention C. Presence of edema D. Intake and output E. Neurological assessment F. Pulmonary assessment G. Cardiac monitoring

Provides information in response to treatment. 1,6,10,13 Monitors for complications.

• Hypotension • Hypertension • Tachycardia/bradycardia • Tachypnea • Fever • Hypothermia 21 • Jugular vein distention • Crackles • Edema • Change in level of consciousness,

dizziness • Change in cardiac rhythm

3. Monitor the circulation to the extremity where the VAC is located.

Assesses for any decrease in perfusion distal to the VAC site. 4,6

• Diminished capillary refi ll • Diminished or absent peripheral

pulses, or pain • Pale, mottled, or cyanotic color • Cool to the touch • Diminished or absent movement or

sensation.




4. Monitor electrolytes, glucose, and albumin during treatment as prescribed or per institutional standards.

Must be monitored because of continued fl uid and electrolyte shifts during treatment. Amino acids are also lost through the hemofi lter.

• Hyperkalemia or hypokalemia • Hypernatremia or hyponatremia • Hypercalcemia or hypocalcemia • Hyperglycemia or hypoglycemia • Hypermagnesemia or

hypomagnesemia • Hyperphosphatemia or

hypophosphatemia • Hypoalbuminemia

5. Administer medications to correct electrolyte abnormalities as needed during treatment. (Level D * )

Patients with renal failure are predisposed to many electrolyte abnormalities. During CRRT, medications or electrolyte replacements may be given as prescribed for individual patients. 6,34 Renal diet with adjusted protein, potassium, phosphorous, carbohydrate, and fl uid intake that takes into account the patient ’ s current catabolic state, renal function, adequacy of dialysis, and removal of amino acids via dialysis is required. 4,6,7,11

• Hyperkalemia or hypokalemia • Hypernatremia or hyponatremia • Hypercalcemia or hypocalcemia • Hyperglycemia or hypoglycemia • Hypermagnesemia or

hypomagnesemia • Hyperphosphatemia or

hypophosphatemia • Hypoalbuminemia • Unexpected change in weight (loss

or gain)

6. Monitor the CRRT circuit (e.g., occlusions; kinks in UF, blood, or vascular access lines; hemofi lter).

Disconnections or introduction of air into the circuit are always possible during treatment. Bleeding or exsanguination can also occur. 3,4,7,10 Clotting of the circuit is a potential complication. If the hemofi lter needs replacing, the extracorporeal blood volume should be returned to the patient if possible. Blood leaks from the dialyzer into the dialysate may occur and necessitate termination of treatment. In the event of a fi lter leak, do not return circuit blood to the patient. Venous or arterial pressures that are out of range may indicate dialyzer or access malfunction.

• Disconnections, cracks, or leaks • Excessive clotting • Blood leaks/hemofi lter rupture • Malfunction of dialyzer or access

7. Monitor UF for rate, clarity, and air bubbles.

A decrease in UF production can occur from clotting of the dialyzer. 4,6,10 Pink or blood-tinged UF is indicative of a fi lter leak or rupture.

• Decreases in UF production • Change in color or characteristics

of UF • Air in UF

8. Administer anticoagulant as prescribed.

Heparin or citrate is often used to prevent clotting of the circuit. 4,6 The heparin/citrate dose varies according to patient condition and laboratory values.

• Suspicion of clotting in the circuit

9. Monitor anticoagulation per institutional standards.

Because heparin or citrate is commonly used to prevent system clotting, coagulation studies should be routinely monitored.

• Abnormal coagulation study results

—Continued

* Level D: Peer-reviewed professional and organizational standards with the support of clinical study recommen dations.



10. Monitor the vascular access. Bleeding and/or infection can occur from the access site. Clotting of the access can occur. 4,6,25,32

• Decrease in access function or patency

• Bleeding • Site redness or edema • Warmth • Purulent drainage • Pain or tenderness • Fever

11. Monitor the patient for complications associated with CRRT treatment.

Complications are possible with CRRT. 4,6,9,10,13,20

• Muscle cramps • Dialysis disequilibrium (headache,

nausea and vomiting, hypertension, decreased sensorium, seizures, coma)

• Air embolism • Dialyzer reaction (hypotension,

pruritus, back pain, angioedema, anaphylaxis)

• Hypoxemia • Hypothermia 21

12. Monitor the blood pump for proper functioning.

Alerts the nurse to problems with the procedure.

• Problems with the blood pump

13. Follow institutional guidelines for assessing pain. Administer analgesia as prescribed.

Identifi es need for pain interventions. • Continued pain despite pain interventions

—Continued

Documentation Documentation should include the following: • Patient and family education • Date and time of treatment initiation, mode of therapy,

fi lter change • Condition of vascular access regarding patency, quality

of blood fl ow, ease of access procedure • Date and time of VAC insertion and dressing change • Condition of insertion site and any signs or symptoms

of infection • Blood fl ow rate and arterial and venous monitoring

pressures • Type and content of dialysis and replacement fl uids • Anticoagulation type and dose

• Completion of informed consent • Vital signs/hemodynamic parameters • Status of pulse distal to vascular access site • Hourly fl uid balance calculation • Patient ’ s response to CRRT and daily progress

toward treatment goals • Unexpected outcomes • Nursing interventions • Daily weight • Laboratory assessment data • Pain assessment, interventions, and effectiveness

References and Additional Readings For a complete list of references and additional readings for this procedure, scan this QR code with any freely available smartphone code reader app, or visit http://booksite.elsevier.com/9780323376624 .

119 Continuous Renal Replacement Therapies - Elsevier

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