Platelet count may predict abnormal bleeding time among pregnant women with hypertension and preeclampsia

Abstract

Background: Anesthesiologists often require laboratory data to estimate the bleeding risk among hypertensive pregnant women prior to administering regional anesthesia. Many rely on the bleeding time (BT) in making this determination. We examined whether the platelet count can adequately predict BT among a group of hypertensive parturients.Methods: This retrospective subgroup analysis, taken from a cohort of 2051 hypertensive pregnant women, comprises 87 individuals who underwent both a BT and platelet count prior to delivery. We calculated the correlation between the platelet count and BT at three platelet cut-off points with respect to prolonged BT of eight minutes or more.Results: There was a significant negative correlation between platelet count at delivery and BT [r= -0.45, 95% confidence interval (CI) -0.26 to -0.60; P <0.0001]. All three platelet cut-off points had a sensitivity of less than 66% with negative predictive values below 75% for an abnormal BT. A platelet count #75 x 10 9 /L was specific for the presence of an abnormal BT (specificity 97.8%, 95% CI 91.7-100.0), with a positive predictive value of 95.5% (95% CI 83.1-100.0) and a positive likelihood ratio of 24 (95% CI 3.3-168).Conclusions: In a group of hypertensive parturients, the platelet count appears to be very specific for predicting a prolonged BT. The

Detecting coagulation disorders of pregnancy: bleeding time or platelet count?

“…In this issue of the Canadian Journal of Anesthesia, McDonagh et al emphasize the high specificity of the platelet count (PC) for predicting a prolonged bleeding time (BT) in pregnant women. 6 The authors provide a well-designed study and a detailed statistical analysis. However, several points merit a more detailed discussion.…”

“…show that thrombocytopenia is associated with a high risk of prolongation of the BT in pregnant women with hypertension but, unfortunately, they do not give much information about the severity of the hypertensive disease. 6 The sensitivity and specificity of any test to assess the severity of the coagulation disorder of pregnancy, and whether this disorder can impair hemostatic capacity remains difficult to investigate.…”

“…McDonagh et al state that the risk of developing a spinal and/or epidural hematoma is directly related to a prolonged BT. 6 However, when studying the risk of this complication, the authors relate the incidence of spinal hematoma to PC, not to BT. Although the theoretical estimation of such a risk is necessarily associated with a wide confidence interval, it could be assumed that these data may be helpful to assist clinical decision-making in thrombocytopenic, preeclamptic patients.…”

“…soulignent la grande spécificité de la numération plaquettaire (NP) dans la prédiction d'un temps de saignement prolongé (TS) chez la femme enceinte. 6 Les auteurs présentent une étude bien conçue et une analyse statistique détaillée. Toutefois, certains points méritent une analyse plus détaillée.…”

“…montrent que la thrombocytopénie est associée à un risque important du prolongement de TS chez les femmes enceintes qui présentent de l'hypertension, mais malheureusement, ils ne fournissent pas beaucoup de renseignements sur la sévérité de l'hypertension. 6 La sensibilité et la spécificité de tout test d'évaluation de la sévérité des troubles de coagulation de la grossesse, et de la possibilité que cela altère la capacité hémostatique, demeurent difficiles à examiner.…”