[The impact of heparin bolus from dysfunctional lumen of dual lumen central venous catheter on activated partial thromboplastin time during hemodialysis: is additional heparinization necessary?].

AIM

The aim of the study was to determine the influence of the heparin bolus, which was administered to a patient due to incapability to aspire heparin from the dysfunctional lumen of dual lumen central venous catheter (CVK), on activated partial thromboplastin time (APTT) values during hemodialysis (HD), as well as to determine the need of additional administration of heparin during HD.

PATIENTS AND METHODS

The first group of examinees consisted of 19 patients with chronic renal failure (CRF) on whom the dual lumen CVK was applied as temporary vascular access, whereby the aspiration of heparin from one of its lumens was impossible. Prior to HD, a coagulogram was determined for all the patients. The testing of this group was carried out in accordance with two different protocols: protocol A and protocol B. Under protocol A, 7,500 IU of unfractioned heparin was injected into the patients' circulation from the dysfunctional lumen of CVK. During the four-hour HD process, APTT were determined after ten minutes, after hours 1, 2 and 3, and at the end of HD. During HD, no heparin was administered and every hour during HD there was visual evidence of blood clots in portions of the extracorporeal circuit system. Under protocol B, the APTT values were determined in the same group of patients according to the previous protocol, with the exception of 750 IU of heparin per hour being administered by continuous infusion to the patients during hours 3 and 4. The second group of examinees consisted of patients with CRF who have undergone dialysis via an arteriovenous fistula, while the testing was carried out under protocol C. The examinees in this group received a bolus of 2,500 IU of heparin at the beginning of HD, followed by a continuous administration of 750 IU of heparin per hour during the first three hours of HD (a total of 4,750 IU during the entire HD). During hour 4, HD was carried out without the administration of heparin. The protocol of determining APTT was identical to that carried out on the previous group of patients.

RESULTS

APTT values prior to HD: A=34.5 +/- 4.27 sec., B=32.38 +/- 4.16 sec. (p=0.457), C=33.66 +/- 3.63 sec. (p=0.245 in relation to protocol A and p=0.281 in relation to protocol B). APTT values ten minutes after the administration of the heparin bolus: A=210 +/- 21.42 sec., B=204.83 +/- 20.82 sec. (p=0.453), C=47.88 +/- 4.26 sec. (p=0.000 in relation to protocols A and B). APTT values after one hour: A=156 +/- 32.76 sec., B=159.66 +/- 30.39 sec. (p=0.377), C=43.88 +/- 4.5 sec. (p=0.000 in relation to protocols A and B). APTT values after two hours: A=81.54 +/- 0.41 sec., B=74.61 +/- 36.39 sec. (p=0.331), C=40.55 +/- 5.29 sec. (p=0.000 in relation to protocols A and B). APTT values after three hours: A=49.6 +/- 8.38 sec., B=59 +/- 8.93 sec. (p=0.395), C=37.88 +/- 2.58 sec. (p=0.000 in relation to protocols A and B). APTT values at the end of HD: A=40.5 +/- 3.97 sec., B=51.44 +/- 5.07 sec. (p=0.154), C=36.66 +/- 4.22 sec. (p=0.399 in relation to protocol A and p=0.222 in relation to protocol B). Clotting was noticed during the third hour of HD in 11 (57.89%) patients under protocol A, in two (10.5%) patients under protocol B and in three (15.78%) patients under protocol C. After comparing proportions for protocols A and C p=0.02, for protocols B and C p=0.998 and for protocols A and B p=0.006

CONCLUSION

Patients who received the heparin bolus from the dysfunctional lumen of dual lumen CVK needed an additional administration of heparin during hours 3 and 4 of HD in order to reduce the frequency of clotting in the extracorporeal circuit system. The frequency of clotting during HD in this study was not dependent on the total dosage of administered heparin, but rather on the means of its administration.