**PLEASE READ BEFORE STARTING YOUR ROTATION**

Dear Resident,

Welcome to the Nephrology rotation. This handout outlines your schedule and responsibilities while on service. There may be variations from attending to attending in protocol but this introduction will provide you with some basic guidelines. The sub-specialty of Nephrology has become surrounded by a certain mystique. Dealing with dialysis for the first time seems to be frightening for everyone but the anxiety is unnecessary. This introduction should give you some of the basics to help reduce your anxiety level and remember: there is always backup available. Most residents find that the rotation is demanding but an excellent educational experience and we hope you will too.

During your rotation, you will be caring for a wide array of Nephrology patients including acute transplant patients, chronic dialysis patients, ICU patients, outpatients, and general Nephrology consults.

1. Schedule
2. Nephrology Services
3. Call
4. Dialysis Order Writing
5. Access
6. Outpatient
7. Access to Dialysis Patient Information
8. Conferences (Weekly Schedule)
9. Keys and Books
10. Useful References
11. For CVVH/D
12. For Acid-Base and Electrolyte Disorders
13. For ARF and Various Renal Diseases
14. Hemodialysis (HD) Order Writing
15. Patient's Weight
16. Dialyzer
17. Dialysate
18. Hours
19. Heparinization
20. Blood Flow Rate (BFR)
21. Access
22. Citrate CVVH
23. CVVHD, CVVH
24. Writing CVVH/D Orders
25. The CVVH/D Flowsheet

Please page the fellow (or attending, if there is no fellow on service) early on the morning you start your rotation for patient assignments, etc.

Work rounds with the attending usually begin at 10:00 AM in the dialysis unit on 8-3400. You should have rounded and written notes on all of your patients by then. Decisions regarding the need for dialysis on acute patients (those whose dialysis needs must be determined daily) should be made by 9:00 AM if possible. We realize that particularly early in the rotation you will need help with these decisions so run them by a fellow (or attending, if the fellow is not available). Scheduling in the dialysis unit is often tight so any changes (admissions, extra treatments, discharges) should be called to the unit as soon as possible.

Consults are directed to the fellow from 8 AM to 5 PM and he/she is responsible for distributing them amongst the team. All consults should generally be seen the day they are called.

A inpatient list is generated everyday by Lynda Redden secretary in the Nephrology unit (53660). She should be notified of any changes or new patients first thing in the morning by the on call person from the night before so the list can be ready for rounds. It is important to provide the patient's name, age, attending, floor, diagnosis, and the person on the team who will be covering him/her.

2. Nephrology Services

Inpatients are divided into two services: you will be on the "acute" service, which consists of new consults, patients with renal insufficiency that are not on dialysis, and recently transplanted patients (within 3 months). The "chronic" service consists of patients already on hemodialysis and patients who were transplanted > three months prior to admission. The chronic service is covered by one of the Nephrology fellows and a nurse practitioner. The latter covers any patients who are regularly dialyzed at Strong Memorial Hospital (either on 8-3400 or AC-1). Transplant nurse practitioners also assist with the care of the chronic transplant patients. Check the daily patient list if you need to know who is assigned to each patient.

3. Call

You will be sent a copy of the call schedule prior to starting. If there are any problems with the schedule, please call Marilyn Miran at (5-3660) and let her know. You will be on call approximately one to two nights per week and one short call weekend (8am. - 4[,) during the rotation. After 5:00 PM on your call days, you will be covering all services, including outpatients. During weekdays any questions regarding "chronic" patients should be referred to the appropriate person on that service (see above).

There is also a separate Pediatric Nephrology service for which you will not be responsible. Questions regarding anyone less than 18 years old should be referred to The Pediatric Nephrologists.

(See sample order sheet and detailed instructions of orders attached)

You will receive instructions on dialysis order writing from the attending or fellow when you begin your rotation. A hemodialysis nurse and technician will also provide an orientation to the dialysis unit when you start. Just introduce yourself to the "charge nurse" in the unit on your first day and they will set a time to orient you at your convenience (and their's). The orders are fairly routine once you are familiar with the basics, similar to ventilator changes in the ICU. The "Handbook of Dialysis" (see below) is a useful resource for routine dialysis concepts and complications. The dialysis nurses are very good at what they do and can often give you guidance or explain how something is done. Remember, if you are not sure about something, ask. All Peritoneal Dialysis orders must be reviewed by the fellow or attending and should be written by 12:00 Noon daily.

(See details about the various types of access used at the end of the section on HD orders below)

Dialysis access should only be used by dialysis personnel except for medical emergencies. Infection and clotting are the major reasons for loss of hemodialysis catheters. Accessing of the lines by individuals other than dialysis nurses greatly increases the risk of developing an infection and possibly losing the line. This access is necessary to keep the dialysis patients alive so treat it reverently.

New access is provided by the transplant surgeons, interventional radiologists, and sometimes, yourself.

Outpatient Nephrology is often a different experience from what you have seen as a house officer. Issues such as the work-up of hematuria, proteinuria, mild renal insufficiency and hypertension are often not seen elsewhere. Nephrology clinic meets two half days/week on AC-3, Tuesday afternoon and Friday morning. Unless there is a conflict with your own house staff group clinic, you will be expected to attend both clinics. Patients will be assigned to you the day before clinic and will be available for review in the clinical office. The list is posted in AC-3 conference room door during clinic on Tuesday pm. and Friday am. Clinic charts are kept in the Nephrology Clinic Office (3-6324). They are then transported to the AC clinic site on the date of clinic. These charts should not leave the AC conference room where the clinic cart is stationed for any reason. If for any reason, you need to review a chart or if you would like to know what times you have patients scheduled for a certain day please contact our scheduling secretary, Donna Wiederhold at 275-4517.

Please let the second year fellow and Marilyn Miran (5-3660) know ahead of time if you are not available for a particular clinic, as your patients will need to be reassigned.

7. Access to dialysis patient information

Charts on Strong hemodialysis patients are kept either in the dialysis unit on 8-3400 or the AC-1 dialysis unit (depending on where the patient is dialyzed); Strong peritoneal dialysis patient charts are on 6-2100. Medication lists and dialysis orders of Clinton Crossings patients can be obtained by calling 461-0770, those of Highland Kidney Center by calling 244-0300, those at Lake Plains in Medina by calling 798-3757, and Batavia patients by calling 344-7098 or 344-7099 and Fingerlakes Unit (Victor) by calling 742-1370. Outpatient labs of Highland and Clinton Crossings patients are sent to Highland Hospital (call 473-2200 and ask to be transferred to the clinical labs).

8. Conferences

See Weekly Schedule. (Click to View Weekly Schedule Online)

9. Keys And Books

Keys to the fellows' office and the transplant office, the drug dosing in renal failure handbook, and the "Handbook of Dialysis" can be signed out from Marilyn Miran in Nephrology Division office, Room 3-6231. These must be returned to Marilyn at the end of rotation. Do not pass them on to another resident or we will have no way of knowing where they are. You are responsible for making sure these find their way back to us.

Other textbooks are kept in the Nephrology conference room on the third floor for your use.

10. Useful References

For HD and PD (and a small amount of CAVH/CVVH/D), the Handbook of Dialysis , Third Edition, 2001. (Daugirdas and Ing, Eds) is provided for you while you rotate on renal. This is an excellent reference for most dialysis problems that arise such as peritonitis, dialysis orders and complications, etc....11. For CVVH/D

Sigler M.H. Transport characteristics of the slow therapies: implications for achieving adequacy of dialysis in acute renal failure. Advances in Renal Replacement Therapy, Vol. 4(1), 1997:pp 68-80. A detailed review of clearance/transport differences between CVVH, CVVHD and CVVHDF.

Seminars in Dialysis. March-April 1996, Vol. 9(2). This whole issue is dedicated to CRRT, with Ravi Mehta (one of the CRRT gurus) as guest editor.

American Journal of Kidney Diseases. Vol. 30(5 supplement 4), November 1997. An entire AJKD supplement on CRRT.

Critical Care Nephrology-Kidney International Supplement No. 66, May 1998. This entire KI supplement is dedicated mainly to ARF in the ICU, with several articles on CRRT. Two of the Guest Editors are Claudio Ronco, an Italian nephrologist and Rinaldo Bellomo, an Australian intensivist. They favor broad use of CRRT in the ICU.

1. Rose, BD: Clinical Physiology of Acid-Base and Electrolyte Disorders. New York, NY, McGraw-Hill, 1994 (Fourth edition).

This book has been referred to by many as "the bible" of acid-base and electrolytes. It's understandable and complete. You'll even understand RTA's when you're done reading about them in here.

2. Halperin, ML and Goldstein, MD: Fluid, Electrolyte, and Acid-Base Physisology-A Problem-Based Approach. Philadelphia, Pa, Saunders, 1994.

Another excellent resource. They use more cases and algorithms, and sometimes take a slightly different approach to problems that Rose.

1. Jacobsen, Striker, and Klahr, eds: The Principles and Practice of Nephrology. St. Louis, MO, Mosby, 1995. This book provides short, to-the-point chapters on just about any renal disease. It's a great starting point for consults on diagnoses such as Cryoglobulinemia, Hereditary Nephritis, etc....

2. Greenberg et al eds: Primer on Kidney Diseases, Third Edition, 2000.

3. Rose, BD: Pathophysiology of Renal Disease. New York, NY, McGraw-Hill, 1987. Excellent chapters on the approach to the patient with renal disease, hematuria, proteinuria, nephrotic-vs-nephritic syndrome, pathology. Chapters on specific diseases may be too basic.

4. Schrier and Gottschalk, eds: Diseases of the Kidney. Boston, MA, Little Brown, and Co., 1993. A three volume set. Goes into lots more detail than 1 or 3. Good for getting details on a specific disease.

Re: Transplantation
Danovitch, GM, ed. Handbook of Kidney Transplantation. Boston, MA, Little Brown, and Co., 1992.

A very legible, understandable guide to the management of patients with renal transplants. Reviews medications, immunosuppression, complications, infections, etc...

A more recent edition is now available with updated information on new medications, etc....

If you have any questions or concerns regarding your rotation please feel free to contact Rebeca Monk (or any of us) at 5-4517. Again, scheduling questions should be addressed to the second year fellows.

Date and time all orders. There are FIRST TIME order sheets in the HD unit (SMH 485 MR) for patients being dialyzed for the first time, or chronic patients just admitted from one of the outpatient dialysis units. Make sure you either hand the charge nurse your orders or that they're placed in the order book, so they don't get lost (not uncommon).

Again, ASK the attending, fellows or nurses if you have any questions at all about order writing, etc. . .

By choosing a weight for a patient, you are stating how much fluid needs to be removed. The estimated ideal weight (EIW) is the "dry weight" determined for each patient. A chronic HD patient with an EIW of 70 kg, for example, comes to HD with weight today of 74 kg which is the pre-weight. Since most chronic patients don't make much urine, weight gain between treatments reflects fluid intake. Last time he was dialyzed, he came off at 69.7 kg. This is the previous-post weight (PPW). You decide he looks very volume overloaded and after chastising him for gaining too much weight in 2 days, order that 4 to 4.5 kg be removed as tolerated. He finishes dialysis without any hypertension or cramps weighing 69.5 kg (his post-weight). You decide that his EIW may actually be lower than previously thought.

In acute patients the EIW is often not known and the amount of fluid that can safely be removed, each treatment is determined by the patient's clinical status and by trial and error. If a weight is not available, the amount of fluid removal required may be estimated by net intake (intake -output) since last HD or since admission. Note that HD and ultrafiltration (UF) (fluid removal) do not have to be done concurrently. Some tenuous patients tolerate UF of large volumes without hypotension if HD is not done at the same time.

The most common dialysis membrane used in our hospital for chronic patients used to be a cuprophane (or cellulosic) membrane. This is the least expensive, but also the least "biocompatible". Currently, we are using a more biocompatible membrane, the F7 or F70 (both made of polysulfone). Biocompatible membranes, such as hemophane, Poly-acrylonitrile (PAN), and polysulfone tend not to stimulate release of as many "bad humors" such as complement, TNF, etc... These should be used in patients with ARF as there is increasing evidence that patients are more likely to recover renal function in the acute setting when using the more biocompatible, synthetic membranes. Some chronic patients have had allergic reactions to certain types of membranes and may need a specific type; their outpatient dialysis orders should note any dialyzer allergies.

Note that chronic dialysis patients are usually on different membranes as outpatients. Check with your attending or the hemodialysis nurses to determine the best SMH membrane for that patient while admitted.

Dialysate is run countercurrent to the patient's blood flow and therefore enhances clearance of toxins by diffusion from an area of high concentration (blood) to low (dialysate). The greater the concentration gradient, the greater the clearance of that particular solute. For example, if a patient has Potassium (K) of 7.2 you need to use dialysate with a very low concentration of K in order to decrease the level quickly. In the middle of the night, for example, you would want to do a short treatment such as 2 hours, against a 0 K bath. If the patient is due for his/her usual 4hour treatment right then, you could probably bring the level down with a 2 K bath. If the patient's K is low, a 4 K bath can be used.
Generally for a standard 3 to 4 hour treatment, with a potassium of:

• High 4's to mid 5's use 3 K
• High 5's to mid 6's use 2 K
• Greater than 6 use 0 K, or combination of 2 and 0

Standard sodium is 140, bicarbonate---35 (if a patient has bicarb levels that are >24, 30, or 25 bicarb baths can be chosen), calcium can be chosen at 2.5 or 3.0 mg/dl (2.5 is standard).

The sodium concentration of the dialysate can be gradually lowered from a high level to low (150 to 135 meq/L, for example). This is called sodium modeling and can be useful in patients who cramp easily or become hypotensive with treatments. Sodium modeling is used primarily for chronic outpatients, rarely in the setting of acute renal failure.

For chronic patients, adequacy of the dialysis prescription is assessed regularly by methods such as the urea reduction ratio (URR) or KT/V. Adequacy can be improved by increasing the size of the membrane, the blood flow rate, or time on dialysis. Most patients, unless they're small or still have good residual renal function (reasonable urine output), require at least 3 ½ hours per treatment, 3 times/week. More is better (less mortality and morbidity), but patients often receive less than the prescribed dialysis because of noncompliance, schedule changes, access problems, etc... Adequacy is often affected by poor access causing recirculation or decreased blood flow (see Access below).

Acute patients need to be assessed daily for dialytic needs. If the patient is hypercatabolic with increasing azotemia despite 3 hours of HD the day before, daily treatments or an increase in the HD time/day may be needed.

19. Heparinization

Most patients require some heparin to prevent clotting of the HD membrane and tubing. In chronic patients, a set dose of heparin is administered as a bolus and then per hour of treatment. Needs will vary per patient. You can order "tight total" heparin, which means the nurses will assess heparin requirements, attempting to minimize the dose. If the patient should not receive heparin, then specifically order "No Heparin." 20. Blood flow rate (BFR) Standard BFR's are about 300-350. Some patients with good fistulas can achieve BFR's of >400, which can mean an increase in clearance without an increase in time. Higher BFR's though may lead to an increase in recirculation of blood, meaning the HD may not be as efficient (see below: access--tunneled catheters). With catheters, there will be significant recirculation at BFR's > 250-300. The maximum achievable BFR is desired. 21. Access

The 4 main types of HD access used are:

1. Short-term catheters (e.g.: Quinton). These are non-tunneled, usually double-lumen catheters that can be placed emergently. They do not need to be placed in an OR by surgeons. Because they are not tunneled under the skin, they are more likely to become infected and should generally not be left in place more than ~3 weeks. Because they are stiffer than tunneled catheters, they also predispose patients to subclavian vein (but not IJ) stenosis.
   
2. Tunneled catheters (e.g.: Permcath). Because these catheters are tunneled under the skin and are made of a softer material, they may be left in place longer than the short-term catheters (weeks to months). These must be placed by the surgeons or interventional radiologists. All catheters are prone to clotting and infection.
   
   Due to the proximity of the holes in the distal end of the catheter, blood just dialyzed and returned to the vein is taken up in the catheter again and redialyzed. This is called recirculation and generally makes HD via catheters much less efficient than that via fistulas or grafts (in which needles can be placed inches apart).
   
3. Arterio-venous fistulas (also referred to as native fistulas) are the optimal form of access for chronic hemodialysis patients. These are created surgically by connecting an artery to a vein. Over a period of several weeks to months, the vein becomes larger and thick enough for cannulation with large-bore HD needles. A strong bruit or thrill is usually indicative of adequate patency and blood flow in the fistula.
   
4. A-V grafts -- are similar to fistulas, but PTFE (gore-tex, impra) is used to connect the artery to the vein. These are required when a patient's vessels are not suitable for native fistula construction. An advantage is that grafts can generally be used for HD within 1-2 weeks (as opposed to 6-12 for a native fistula), but grafts are more likely to thrombose, and when infected, are harder to treat (usually requiring surgical removal).

Some patients are unable to tolerate CRRT with heparin because of the risk of systemic anticoagulation or because of heparin-induced thrombocytopenia (HIT). An alternate method of anticoagulation that avoids clotting of the filter and lines (the "system") but does not anticoagulate the patient is citrate regional anticoagulation. Calcium is a necessary cofactor in various steps of the clotting cascade. Citrate chelates calcium, and therefore is a potent anticoagulant. While citrate infused pre-filter maintains patency of the system, the citrate that returns to the systemic circulation is broken down to bicarbonate by the liver. The bound calcium is then restored to the blood and no systemic anticoagulation ensues. Adequate calcium levels and systemic coagulation are also maintained by a continuous calcium infusion via a separate IV line. In order to maintain adequate anticoagulation, there must be a favorable citrate: calcium ratio. Therefore, it is necessary to reduce the blood-flow with this method in order to decrease the amount of calcium that must be bound by the infused citrate. Generally, the procedure is similar to CRRT with heparin. The differences are that a citrate replacement solution (with sodium, magnesium and dextrose-prepared by the pharmacy) is infused prefilter at 1500 ml/hr, and no other replacement solutions, dialysate, or heparin are required. Ionized calcium levels are checked q 4 hours and the total calcium is checked q 12 hours. No PTT levels are necessary. A calcium infusion is provided by a separate line directly into the patient (not via the CVVH machine) based on the levels drawn. The blood flow is maintained at 120 ml/min. Though the blood flow is slower than with heparin, and no dialysate is used, the higher replacement solution rate and improved system patency tend to provide adequate clearances.

Patients with severe liver disease or lactic acidosis are at risk for developing citrate toxicity. The resultant excess citrate can lead to a potentially fatal reduction in the ionized calcium level. Monitoring calcium levels, therefore, is crucial in all patients. One clue that may point to elevated citrate levels in the blood is a high "calcium gap", i.e. high total calcium with a low ionized calcium level.

This method is still quite new at SMH, so be sure to have the attending or fellow assist you with the orders.

Continuous renal replacement therapies (CRRT) include CVVH, CVVHD, CVVHDF, CAVH/D/F and slow continuous ultrafiltration (SCUF). CVVH/D/F are the only CRRT done at SMH. These are slow, continuous modalities that allow for large fluid and solute removal with potentially greater hemodynamic stability. They are ideal for patients in the ICUs who are too ill to tolerate conventional HD. They are also useful for hypercatabolic patients who require large amounts of solute clearance to control electrolytes and azotemia. Patients with end-stage liver disease may develop increased intracranial pressure with intermittent hemodialysis but not with CRRT. Many believe that the convective middle molecule clearance achieved with CRRT may be useful in removing inflammatory mediators of sepsis, but this remains controversial.

By running these treatments 24 hours/day, large amounts of fluid can be gently removed. For example, 3 liters of fluid can be removed at 125 ml/hr with CRRT (when discussing CVVH, CVVHD or CVVHDF in general, I will refer to all as CRRT) as opposed to ~1 liter/hr with HD. In this manner, one can safely achieve net fluid removal of the patient's entire daily intake as well as any additional fluid removal desired.

The Prisma CRRT machine we use provides a blood pump, dialysate pump, and replacement solution pump, scales that monitor ultrafiltration, pressure sensors and air-bubble detectors. As the blood flow is continuous and slow, heparin is often required as a small hourly infusion to prevent clotting of the system. CRRT should be attempted without it if the pt has liver disease, a low platelet count or other coagulopathy. In such patients, CRRT may be performed successfully without heparin. The technique is simple: Blood passes through a membrane where a large amount of ultrafiltrate is formed (analagous to urine, though it is formed in an artificial kidney), and blood is returned to the body (just like HD). The membrane is composed of polyacrylonitrile (PAN), a synthetic, biocompatible substance (see Dialyzer section on page 6 regarding biocompatibility). Any ACE-inhibitors should be discontinued due to the potential risk of anaphylaxis in patients exposed to PAN membranes on ACE-inhibitors. Importantly, these membranes also have a large surface area and are very leaky (i.e. porous), allowing water and solutes to easily filter through. This dragging out of solutes (ions, BUN, creatinine, etc.) is termed convective clearance and is the only type of clearance provided by CVVH.

When dialysate is run countercurrent to the blood flow through the membrane, diffusive clearance is added. With CVVHD, osmosis moves particles from an area of high concentration (blood) to low concentration (dialysate). Diffusive clearance exceeds convective clearance in CVVHD. The dialysate we use is 1.5% Dianeal used for peritoneal dialysis. The dialysate provides lactate as a base, which is converted to bicarbonate in the liver (therefore watch for lactic acidosis in patients with severe liver disease)-if lactate levels rise, you may want to switch back to CVVH from CVVH/D. The standard dialysate flow rate is 1 L/hour, though this can be increased in extreme cases when better azotemia control is required. In CVVHDF, convective clearance and diffusive clearance are proportional. Ultrafiltration (fluid removal) is increased in order to increase convective clearance. Infusing a replacement solution stabilizes intravascular volume and prevents hemoconcentration. Generally, these solutions contain either sodium bicarbonate or calcium gluconate in order to improve acidosis or replete calcium losses.

At first reading, this may seem complicated, but will become very simple after you do it a few times:

We have a Prisma machine to perform CVVH, CVVHD and CVVHDF. Writing orders requires that you have the ICU flow sheets for the last 24 hours handy. Look at the example for John M.O.F. Smith:
#1. His weight is 150 kg, but let's assume his admission wt was 110 kg: He will be needing fairly aggressive volume removal over time.

#2. Vascular access for CVVH/D should be a catheter. We have done it sporadically through a dialysis patient's fistula, but catheters are preferred as fistulas can clot, needles can fall out, etc…

#3. a.) The Hospal AN69 filter is the standard filter we use for adults.
B.) Decide if you want to do CVVH, CVVHD, or CVVHDF.

#4. Blood flow rate can be variable. 150 -180 ml/min is optimal. If the patient is very hemodynamically unstable, however, you may wish to initiate CRRT at a lower blood flow rate.

#5. This is the tricky part of the order writing: figuring out how much fluid to have the machine remove each hour.

You would like to start by removing a net of 2 liters each day. This means that no matter what the patient takes in or excretes, he will be negative by 2 liters after 24 hours. The prescribed weight loss (A) is therefore 2000ml/24 hours.

For B and C, you need the flowsheets. You look at the ICU flowsheets and see that in the last 8 hours (which is pretty representative of his last 24- 48 hours) he's taken in1200 mls (iv fluids, medications, etc…). This translates to a prescribed intake (B) of 3600 ml/24 hours. His output over the last 8 hours (eg, stool, urine, drains, etc…) was 600, which translates to output (C) of 1800 ml/24 hours.

Do the calculations on the order sheet: A + B - C (prescribed wt loss + input - output) and you get (D) the desired actual pt fluid removal. In this case: 2000 ml + 3600 - 1800 = 3800 ml/24 hours. In order to determine the hourly removal that needs to be ordered, divide by 24 to get (E), the desired actual pt fluid removal in ml/hr. In this case, 3800 divided by 24 = 158.3. For the Prisma, you need to round to the nearest 10's. Therefore you could order the fluid removal at 150 or 160-in this case, 160 ml/hr would be closest to your calculations.

#6. If the patient is very tenuous hemodynamically and has ongoing drops in his BP or hct requiring frequent fluid or blood boluses, you may elect to not count them as part of the intake-i.e. the nurses will write them in the flow sheets as "extra fluid", rather as part of the other hourly intake. In this way, the patient will be receiving extra fluid than what you prescribed to be removed. In the case of our sample pt, by checking the box at # 6, you are ordering any extra fluid to be counted as part of his regular I's and O's. In other words, you want to stick to your original orders for fluid removal. If he continues to get large boluses of extra fluid, you may want to repeat the calculations and increase the "desired patient fluid removal" to a larger number or you may decide that this is too much fluid removal given his hypotension, and that you need to decrease the goal.

#7. Standard dialysate infusion is at 1 liter/hour.

#8. Heparin infusions are usually required. Start with a low dose and increase as needed, based on PTT checks. Note that heparin is infused prefilter (before the membrane in order to keep it from clotting) and the PTT's are checked in a postfilter blood drawing port-right after the membrane but before getting back to the patient. This helps ensure that we anticoagulate the membrane, but not necessarily the pt.

#9. Frequent lab draws to assess electrolyte status is very important given the potential high solute clearance with this procedure. The pt may require frequent replacement of calcium, bicarbonate, potassium, magnesium, etc…

#10. All patients receiving HD or CVVH/D for the first time need Hep B and C screening. If patients are Hep B Sag or Hep C +, the machines need to be cleaned with special solutions. (Note that universal precautions are taken in all patients, and that no tubing or membranes are reused in patients on CVVH/D).

#11. Replacement Solutions: when doing CVVHDF, the addition of a replacement solution at 1 L/hour will automatically result in additional ultrafiltration of 1 L/hour. This will greatly increase convective clearance. With increased clearance, be alert for large electrolyte losses (especially, potassium, magnesium, calcium, and phosphorus). You will likely need to replace large amounts of these. If more calcium is required, you can increase the amount of calcium in solution from 1 to 2 amps/L of NS (or more). Similarly, bicarbonate can be given for severe metabolic acidosis. 50 mEq = 1 amp. You can increase the dose to up to 3 amps in D5W. Calcium and bicarbonate should not infuse together in the same line. You may wish to alternate liters of bicarb and calcium if both are required (preferably at the same rate so that the machine does not need rate adjustment each time you switch from one to the other).

#12. As potassium is easily removed by CVVH/D, you can add it to the dialysate to prevent hypokalemia. The dialysate comes in 3 L and 5 L bags. If you add 9 mEq of KCl to a 3 L bag or 15 mEq to a 5 L bag, you have added 3 mEq/L, creating a "3K" dialysate. If the potassium is very low, you may want to add more, if it is high, you may want less or none at all-check with your fellow, attending, or HD nurse for any questions regarding KCl repletion.

See example provided for the same patient:

The "Actual Patient Fluid Removed" refers to the amount of fluid you have ordered removed each hour. This is the same as the "desired actual pt fluid removal" in ml/hr that you calculate on the order sheet. This remains constant each hour unless you order a different rate.

Note that the words "actual fluid removed" are a misnomer as they imply net fluid loss, but actually refer to the ultrafiltration rate that you have ordered.

The "Return Pressure" refers to the pressure sensed as the blood is returning to the patient. Increases in this pressure can signify problems with return of blood which could be due to catheter problems (? kink, clotting), or clotting of the membrane.

Note in the flow sheet that CVVH/D started at 8 am and the 8-hour cumulative record for that shift shows a net fluid removal of 645 mls. If his I's and O's remain relatively constant, over 24 hours, the net fluid removal should be 645 x 3 = 1935 mls, which is pretty close to the 2000 mls net fluid removal you prescribed (#5A on order sheet). At 1600 and 1700, however, his input begins to rise dramatically and his net fluid removal is negative which means he is actually retaining fluid. You talk to the nurse and look at the ICU flowsheets. He is now receiving HAL at 100 ml/hr and an increase in antibiotics (by ~50 - 100 ml/hr) for his new temp spike. You decide to increase his goal by 175 ml/hr to 160 + 175 = 335 ml/hr. Now the fluid removal is positive. He does well for 2 hours but the system clots off-something you may have anticipated from the rising return pressures and the low PTT. When you restart the machine, you will want to reorder the higher fluid removal rate, as well as an increased dose of heparin if bleeding is not a problem.

ENJOY!