Report on the Heparinization Project

Southern California Renal Disease Council, Inc.
ESRD Network 18

PURPOSE: To confirm the impression of some on the Medical Review Board that single boluses of heparin are used for anticoagulation in many dialysis facilities in Network 18. If this impression is correct, to determine if any adverse consequences of this approach can be identified.

BACKGROUND: It is essential to administer heparin to nearly all patients undergoing hemodialysis in order to prevent clotting of the extracorporeal circuit during the dialysis treatment. There is no standard of care for heparin administration in the dialysis setting, but the most recent prevalent practice is to give a bolus of heparin at the beginning of treatment, followed by hourly boluses of heparin during treatment. (“Bolus” refers to the starting dose of heparin at the beginning of a hemodialysis treatment that is not removed from the patient.) A less common approach is to give a larger bolus of heparin at the beginning of the treatment. The latter approach has the theoretical risk of resulting in systemic anticoagulation, and may require closer monitoring to be certain that excessive coagulation is not occurring. Since 1991, however, with the advent of CLIA, most dialysis facilities are no longer “certified” to use the activated clotting time (ACT) or other tests as an on-site measure of systemic anticoagulation during dialysis. The effects of heparin administration during dialysis, therefore, are essentially not quantified. Because of the larger dose of heparin given as a single bolus at the onset of dialysis treatment, concern has been raised about the safety of this approach when no laboratory monitoring is taking place.

HYPOTHESIS: Facilities using a “bolus-only” approach to heparin administration for patients on in-center hemodialysis will be using a significantly greater total amount of heparin per treatment than facilities using a “bolus plus hourly” approach to heparin administration.

METHOD: A 20% random sample of all hemodialysis patients in all facilities during a one-month time frame was drawn, using the last digit of the social security number. Facilities were asked to submit one hemodialysis treatment record per patient on their pre-assigned list for the first treatment of the month of July, 1998. Patients who were excluded from the study included those who were hospitalized, on vacation, transferred out, or any who were not present in the facility during that month. Patients who did not have a social security number, and in the final analysis, patients who had no heparin dosage given during treatment were also excluded.
The original patient sample drawn was 2981; 2834 eligible forms were returned from 182 dialysis facilities. A database was set up to enter relevant data per patient. Indicators were: Bolus (or loading dose) of heparin, hourly heparin dose, number of hours heparin given, total heparin, time on dialysis, pt. weight, blood flow rate, type of access, and type of dialyzer. 

RESULTS: Patient forms were arranged by company affiliation, then divided into two major groups: 1) those receiving “bolus only” heparin (defined as greater than 60% of patient population with no hourly heparin, with the exception of patients with a catheter access); and 2) those receiving both “bolus plus hourly” heparin dosages during treatment.

A t-test was run on the two groups to test for differences between the means (the total amount of heparin given during treatment). Using a p value of >.05, the t-test result showed that there was no significant difference between the means of the two groups. By observation, although the two groups were different in size, they had identical median heparin dosages.
Non-statistical facility results were also grouped by company:

FINDINGS: Overall, the basic hypothesis that there would be major differences in the total heparin dosages between the bolus-only versus bolus-plus-hourly patients was disproved in this small study. Corporate policies affected how heparin was administered, but facilities with the most “bolus-only” heparin level did not have the highest total heparin levels. Another aspect of this study could involve correlating mean hematocrits and EPO administration rates of the facilities with the mean total heparin administration during the same time period.

DISCUSSION: However, there were many quality-related problems related to documentation and usage of heparin in Network 18 facilities:
· Many treatment forms had missing information or illegible handwriting.
· Often, there was no correlation between pre-printed prescriptions for heparin and actual delivered dosages.
· Heparin doses were often written as “cc’s”, not units of heparin, with no corresponding dilution documented. (It was inferred as 1000 U:1 ml.)
· It was often unclear exactly how much “hourly” heparin was given (or the number of times) during treatment.
· Many forms did not have “Total Heparin” listed (or at least number of hours given), or any section for heparin given during treatment. The terms “prime”, “load” and “bolus” were often used interchangeably (actual dose, or a set-up only?).

RECOMMENDATIONS: These are quality issues the dialysis facilities in Network 18 should look at internally, as future topics for quality improvement.
The Medical Review Board continues to support efforts of national organizations to reinstate the ACT test on the dialysis facility level to better monitor heparin administration for hemodialysis patients.