Hemostatic function in healthy pregnant and preeclamptic women: an assessment using the platelet function analyzer (PFA-100) and thromboelastograph.
BACKGROUND
The PFA-100 is a point-of-care platelet function analyzer which measures the speed of formation of a platelet plug in vitro, expressed as closure time (CT) in seconds. This device could potentially be used to assess primary hemostasis prior to regional anesthesia. In this prospective, observational study we sought to establish 95% reference intervals for PFA-100 and Thromboelastograph (TEG) values for our normal pregnant population, before comparing the PFA and TEG in measuring platelet function in preeclamptic and healthy pregnant women at term, using confidence interval analysis and analysis of variance.


METHODS
Routine hematologic and coagulation tests were performed along with von Willebrand Factor, CT, and TEG measurements. Results are expressed as mean (sd).


RESULTS
Increased severity of preeclampsia was associated with increasing prolongation of CT, even in the presence of normal platelet counts. In severe preeclampsia, the PFA-100 CT (mean (sd): 155 (65) s) exceeded the 95% reference interval of the control group (70-139 s). In contrast, TEG maximum amplitude (MA) in severe preeclampsia (mean (sd): 71 (8) mm) remained within the 95% reference interval for MA in normal pregnancy (64-82 mm).


CONCLUSIONS
We conclude that impairment of primary hemostatic function with increasing severity of preeclampsia was recorded by the PFA-100 but not the TEG.
Davies
Jeremy R
JR
Department of Anesthesia, Royal Free Hospital, Pond St., London, United Kingdom.
Fernando
Roshan
R
Hallworth
Stephen P
SP
D000328:Adult; D001780:Blood Coagulation Tests; D005260:Female; D006487:Hemostasis / Q000502:physiology*; D006801:Humans; D010976:Platelet Count / Q000295:instrumentation* / Q000379:methods; D010979:Platelet Function Tests / Q000295:instrumentation* / Q000379:methods; D011225:Pre-Eclampsia / Q000097:blood* / Q000175:diagnosis*; D011247:Pregnancy; D011446:Prospective Studies; D013916:Thrombelastography / Q000295:instrumentation* / Q000379:methods