Format

Send to

Choose Destination
J Cardiothorac Vasc Anesth. 2004 Oct;18(5):581-6.

Dose-response relationship between plasma ionized calcium concentration and thrombelastography.

Author information

1
Department of Anaesthesia, Groote Schuur Hospital and University of Cape Town, Western Cape, South Africa. james@cormack.uct.ac.za

Abstract

OBJECTIVES:

To establish the threshold value for calcium at which coagulation commenced and to investigate the range over which changes in ionized calcium influenced coagulation.

DESIGN:

Controlled, nonblinded, in vitro observational study.

SETTING:

The study was conducted in a university-based laboratory.

PARTICIPANTS:

Blood was obtained from healthy volunteers.

INTERVENTIONS:

One hundred samples of citrated blood were recalcified using varying quantities of 10% calcium chloride solution. Heparinized samples from the recalcified blood were obtained for measurement of ionized calcium concentration (Ca(2+)).

MEASUREMENTS AND RESULTS:

Coagulation of the recalcified samples was analyzed using thrombelastography. The ionized calcium concentration in recalcified blood was measured using a calcium electrode in a blood gas analyzer. No sample with a Ca(2+) < 0.33 mmol/L showed any clot formation. Normal coagulation measures were obtained in almost all samples in which the Ca(2+) was >0.56 mmol/L. Final clot strength appeared to be independent of Ca(2+) once the threshold value of 0.33 mmol/L was exceeded.

CONCLUSIONS:

Ca(2+) of <0.33 mmol/L is necessary to prevent coagulation. Ca(2+) > 0.56 is unlikely to be the cause of coagulation abnormalities during surgical procedures in which calcium metabolism is deranged. Between these values, Ca(2+) may exert an effect on the rate of clot formation, but final clot strength should be unaffected.

PMID:
15578468
DOI:
10.1053/j.jvca.2004.07.016
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center