Fresenius Medical Care North America Corporate Headquarters Medical Department To: FMC Medical Directors 95 Hayden Avenue

Transcription

1 Internal Memo Fresenius Medical Care North America Corporate Headquarters Medical Department To: FMC Medical Directors 95 Hayden Avenue Lexington, MA From: J. Michael Lazarus, M.D. & the Bicarbonate Committee (Julie Brennan, Catherine Dubinsky, Paul Genoa, Maureen Herget, Phone: (781) Ext Chinu Jani, Nancy Lew, Norma Ofsthun, Dave Updyke, Scott Walker) Fax: (781) Date: December 7, Re: Bicarbonate Dialysate and Low Serum Bicarbonate Levels We recently corresponded with you concerning the problem of acidosis and our findings that there was no affect of shipment of blood specimens by either air or ground transportation on serum C0 2 levels. Further review of FMCNA data indicated that many facilities have an unacceptable number of patients with pre-dialysis bicarbonate levels below 18 mmol/l. It appears that in many cases, physicians have ignored this finding, assuming it to be a laboratory error. Let me again assure you that, for the most part, the finding of low pre-dialysis bicarbonate levels is not related to laboratory error or transportation of blood specimens. It may well be related to errors in the collection of blood samples by facility staff, but more importantly, may be related to an inadequate dialysate bicarbonate prescription. Since low pre-dialysis bicarbonate levels seem to be a greater problem than we expected, we further evaluated laboratory results along with dialysate bicarbonate orders. Findings are summarized in the following pages.

2 Internal Memo Page: 2 Date: 12/07/2000 Figure 1 demonstrates the distribution of pre-dialysis bicarbonate levels in 47,529 FMCNA patients who were so tested at Spectra East in July of Figure 1. Distribution of Patient Pre-Dialysis Bicarbonate Levels in July ,000 5,000 N=47,529 Normal Predialysis Range Number of Patients 4,000 3,000 2,000 1, Pre-Dialysis Serum Bicarbonate Concentration (mmol/l) The shaded box outlines the normal range of pre-dialysis bicarbonate levels as determined by experts in the field (see references). The K/DOQI recommendation for pre-dialysis plasma bicarbonate levels is 22 mmol/l or greater. Approximately 58% of patients are below the recommended level of 22 mmol/l.

3 Internal Memo Page: 3 Date: 12/07/2000 Figure 2 shows the distribution broken out by hemodialysis and peritoneal dialysis patients. Figure 2. 14% 12% Distribution of HD Patient and PD Patient Pre-Dialysis Bicarbonate Levels in July 2000 Normal Predialysis Range All HD (N=43,716) All PD (N=3,301) Percent of Patients 10% 8% 6% 4% 2% 0% Pre-Dialysis Serum Bicarbonate Concentration (mmol/l) It has been previously reported that PD patients have higher bicarbonate levels than HD patients, which we reconfirm. The lactate level for PD fluids in our PD program is either 35 or 40 meq/l depending on calcium and magnesium content.

4 Internal Memo Page: 4 Date: 12/07/2000 Figure 3 shows the distribution of the percentages of HD patients in facilities with pre-dialysis plasma bicarbonates below 22 mmol/l. Figure 3. Distribution of Percentages of Hemodialysis Patients in Facilities with Low Pre-Dialysis Plasma Bicarbonate Levels Percent of Facilities 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% 2% 0-5% 0% 5-10% 1% 10-15% 2% 15-20% 2% 2% 20-25% 25-30% 3% 30-35% 5% 35-40% 7% 40-45% 9% 45-50% 8% 50-55% 7% 55-60% 8% 8% 8% 60-65% 65-70% 70-75% 7% 75-80% 6% 6% 80-85% N=897 facilities July, 2000 % of Patients with Pre-Dialysis Plasma Bicarbonate < 22 meq/l 85-90% 4% 4% 90-95% % From this figure, you can see that 66% of facilities had 50% or greater of patients with a predialysis serum bicarbonate level < 22 mmol/l and 93% of facilities had 25% or greater of patients with a pre-dialysis serum bicarbonate level < 22 mmol/l. All of the facilities use Spectra East and supposedly employ the same blood collection technique. Thus, we believe these differences are facility specific. These findings led us to study a sample of 58 facilities to assess possible factors in low predialysis serum bicarbonate levels. We selected 14 high C0 2 facilities each with mean predialysis serum bicarbonate level 22 mmol/l and above, 20 medium C0 2 facilities each with a mean pre-dialysis serum bicarbonate level between 18 and 22 mmol/l, and 24 low C0 2

5 Internal Memo Page: 5 Date: 12/07/2000 facilities each with a mean pre-dialysis serum bicarbonate level < 18 mmol/l. We determined the total buffer (i.e., both bicarbonate and acetate) provided in the dialysate for the hemodialysis patients in each of those 3 groups. We subsequently studied a subset of these facilities a second time to determine the post-dialysis serum bicarbonate value. The results of this study are shown in Table I. Table I First Study Pre / Post Study High Group # Facilities # Patients Average Predialysis Serum Bicarbonate Level Average Total Dialysate Buffer (Bicarb & Acetate) # Facilities # Patients Average Predialysis Serum Bicarbonate Level Average Predialysis Serum Bicarbonate Level Average Total Dialysate Buffer (Bicarb & Acetate) mmol/l 43.2 mmol/l mmol/l 31.0 mmol/l 42.2 mmol/l Medium Group mmol/l 38.9 mmol/l mmol/l 28.9 mmol/l 39.0 mmol/l Low Group mmol/l 36.3 mmol/l mmol/l 23.8 mmol/l 35.9 mmol/l The weighted average bicarbonate in the high group was 24.5, the average in the middle group was 20.6, and the average in the low group was Values were very similar on repeat testing in 14 facilities some several weeks later. The post-dialysis weighted averages were 31.0, 28.9, and 23.8, respectively. We then examined these findings in relation to the total buffer provided in the dialysate. In the high group, the weighted average total buffer provided in dialysate was 43.2 mmol/l, in the middle group 38.9 mmol/l, and in the low group 36.3 mmol/l. Dialysate bicarbonate was similar in the first and second studies.

6 Internal Memo Page: 6 Date: 12/07/2000 Figure 4 shows a plot of the facility mean pre-dialysis serum bicarbonate levels vs. the total dialysate buffer. In general, it appears that one must order a total dialysate buffer of 38 to 40 mmol/l to obtain a mean facility serum bicarbonate level of 22 mmol/l. Figure 4. Facility Mean Pre-Dialysis Bicarbonate vs. Total Dialysate Buffer 28 Facility Mean Pre-Dialysis Serum Bicarbonate (mmol/l y = 0.778x R 2 = Total Dialysate Buffer (mmol/l) To obtain a clearer understanding of how to obtain total dialysate buffer, Table II illustrates the total dialysate buffer obtained from various dialysate series with different dialysis machine bicarbonate settings.

7 Internal Memo Page: 7 Date: 12/07/2000 Table II Examples to Obtain Indicated Total Buffer 9000 Series (Liquid) Bicarb Setting Acetate Bicarb Setting 9000 Series GranuFlo Acetate Bicarb Setting 6000 Series GranuFlo 6000 Series (Liquid) 4000 Series (Liquid) Acetate Bicarb Setting Acetate Bicarb Setting Acetate Total Buffer You must consider that the buffer activity from acetate in the acid solution contributes to the total buffer particularly in the GranuFlo dialysate.

8 Internal Memo Page: 8 Date: 12/07/2000 Figure 5 shows the distribution of dialysate bicarbonate prescribed in all patients most recent hemodialysis order as of June 30, 2000 (57,191 patients). Figure 5. Distribution of Dialysate Bicarbonate Prescribed in each Patient's Most Recent HD Orders as of 6/30/00 80% 70% Percent of Patients 60% 50% 40% 30% 20% 16.42% 51.81% 25.1% 10% 0% 0.48% 1.50% 0.73% 1.00% 0.78% 0.23% 1.17% 0.75% 0.0% <= >41 Bicarbonate Concentration (mmol/l), rounded to nearest integer Approximately, 16% of patients received a dialysate bicarbonate of ~ 32 mmol/l, 52% received a bicarbonate dialysate of ~ 35 mmol/l, and 25% received a bicarbonate dialysate of ~ 39 mmol/l. This reflects the distribution of facility-wide dialysate orders, since most physicians order the same dialysate bicarbonate for most patients in the facility. Further search revealed that 63% of facilities currently use the 9000 Series, 34% utilize the 6000 Series, and 2% utilize the 4000 series. Twenty-nine (29) facilities are currently using GranuFlo with either the 6000 or 9000 Series. Because of the increased acetate in the acid portion of GranuFlo powder (which is metabolized to bicarbonate), significantly higher base is delivered. We have begun to monitor final dialysate bicarbonate levels in facilities on a regular basis. In the past, we have not measured the dialysate bicarbonate level. In the most recent monitoring period, 363 machines were monitored and delivered dialysate bicarbonate levels within 2 mmol/l of the prescribed level. I encourage you to review the random sampling of dialysate bicarbonate levels being carried out in your facility.

9 Internal Memo Page: 9 Date: 12/07/2000 I have provided a copy of this memo along with 4 reference articles and the K/DOQI Guidelines on the FMCNA Intranet*. It is clear that acidosis has a serious negative impact on nutrition and bone disease as well as mortality. It seems prudent, therefore, that physicians strive to achieve a pre-dialysis bicarbonate level at or slightly above 22 mmol/l in individual dialysis patients. I urge you to review each individual patients bicarbonate levels in your facility and your overall facility distribution. If patients in your facility have low mean serum bicarbonate levels, or there are a high percentage of patients below 22 mmol/l, I recommend you review and monitor blood collection techniques with the facility staff. If a significant percentage of patients consistently exhibit serum bicarbonate levels below 22 mmol/l, we suggest you consider increasing the dialysate bicarbonate level or patients should receive base (NaHC0 3 ) orally to achieve these levels. It appears that, except in the case of GranuFlo, the dialysis machine bicarbonate settings should be 35 mmol/l or higher since below that prescription, very low serum bicarbonate levels occur in a high percentage of patients. Depending on the concentrate type, it may be necessary to set the machine dialysate bicarbonate as high as 40 mmol/l for some patients. In patients who have normal to high pre-dialysis levels, or in whom you have concern for the affects of high post-dialysis levels which may be adversely affect a co-morbid condition, individual dialysate bicarbonate levels should be prescribed. I would appreciate your comments or suggestions regarding the treatment of acidosis. *Go to the FMCNA Intranet site ( ), type in your User ID and Password. On navigation bar, click on the red Services tab. Under Clinical Library/Medical Directors Information, click on Medical Director s Memos and then click on the above titled memo. You can print out the articles if so desired. JML/kr xc: See Distribution List

10 Internal Memo Page: 10 Date: 12/07/2000 References Articles Posted on FMCNA Intranet: 1. Gennari FJ: Acid-base balance in dialysis patients. Semin Dial 13(4): , Chauveau P, Fouque D, Combe C, Laville M, Canaud B, Azar R, Cano N, Aparicio M, Leverve X, and the French Study Group for Nutrition in Dialysis: Acidosis and nutritional status in hemodialyzed patients. Semin Dial 13(4): , Kraut JA: Disturbances of acid-base balance and bone disease in end-stage renal disease. Semin Dial 13(4): , Grassmann A, Uhlenbusch-Körwer I, Bonnie-Schorn E, Vienken J: Composition and Management of Hemodialysis Fluids (Good Dialysis Practice; Vol. 2). Lengerich; Berlin; Riga; Rom; Wien; Zagreb: Pabst, p 51, pp K/DOQI Nutrition in Chronic Renal Failure. Am J Kidney Dis 35(6) Suppl 2(June):S38- S39, (Text unavailable) 6. K/DOQI Nutrition in Chronic Renal Failure. Am J Kidney Dis 35(6) Suppl 2(June):S107- S108, (Text unavailable)

11 Tom Amitrano Jose Diaz-Buxo, M.D. Mark Costanzo Kathy Crocker Craig Dawson Prof. Jutta Passlick-Deetjen Linda Donald Ann Eckert Deb Harvey Doug Kott Ron Kuerbitz Gordon Lang, M.D. Nathan Levin, M.D. Ben Lipps John Markus Dwight Morgan Coleman Mosley, M.D. Bill Numbers Brian O Connell Michael Perry Alexis Porras Rice Powell Chris Pricco Mohsen Reihany Joe Ruma Jeff Sands, M.D. Gary Scher Heinz Schmidt Kathleen Smith Donna St. Pierre Jeff Weix Gail Wick Hock Yeoh, M.D. Business Unit Compliance Officers Business Unit VPs of Quality Clinical Quality Managers (6) c/o Gisele Kay DSD Regional Managers DSD Regional Quality Managers DSD Regional Vice Presidents Distribution List Bicarbonate Dialysate and Low Serum Bicarbonate Levels Medical Director Memorandum

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