Preoperative predictors of thrombocytopenia in Caesarean delivery: is routine platelet count testing necessary?

Abstract

Peri-partum thrombocytopenia significantly impacts anaesthetic technique and increases the risk of perioperative bleeding. However, as less than 5% of normal pregnancies have significant thrombocytopenia, routine platelet testing incurs great cost for a relatively low yield. Determining whether clinical predictors, in particular HIV status, are associated with thrombocytopenia may assist clinicians in rationalising preoperative testing. Methods: This was a prospective, observational, single-centre study at a South African regional hospital. We evaluated five variables as candidate predictors for mild preoperative thrombocytopenia (< 150 000/μl) in patients scheduled for both elective and emergency Caesarean delivery: HIV status, pre-eclampsia, urgency of surgery, renal impairment and liver failure. As a subanalysis we compared the incidence of moderate thrombocytopenia (< 100 000/μl) in HIV-positive patients, with HIV-negative patients. Results:We recruited 1 015 patients to this study. The incidence of mild thrombocytopenia was 10.3% (105/1 015). Only preeclampsia was predictive of mild thrombocytopenia (odds ratio 3.51; p < 0.01; 95% confidence interval 2.12-5.82). The incidence of moderate thrombocytopenia was not influenced by HIV status (occurring in 1.5% of HIV-positive patients versus 1.8% in HIVnegative patients; p = 0.716). Conclusions: In this study of predominantly asymptomatic patients scheduled for Caesarean delivery, only pre-eclampsia was predictive of mild thrombocytopenia. In sub-analysis HIV status was not independently associated with moderate thrombocytopenia. All asymptomatic patients, including those who were HIV positive, had platelet counts > 70 000/μl.

A retrospective audit of anaesthesia for caesarean section in parturients with eclampsia at a tertiary referral hospital in Cape Town

“…Haemoglobin (g/dL) 11 [11][12][13] 12 [11][12][13] 12 [11][12][13] Platelet in the latter period. 8 Our findings were that SA in patients with eclampsia and GCS ≥ 14 appears to be safe and possibly associated with better outcomes for both mother and child.…”

“…10 The incidence of thrombocytopaenia in pregnancy with a platelet count < 75 × 10 9 /L is approximately 1%. 11 A thromboelastography study showed that the maximum amplitude decreased markedly in patients with preeclampsia when the platelet count decreased to below 75 × 10 9 /L. 12 In a recent Pregnancy Practice Bulletin of the American College of Obstetricians and Gynecologists, the recommended lower limit of the platelet count for safe neuraxial anaesthesia is 80 × 10 9 /L.…”

Coagulation in the HIV-positive pregnant patient : a thromboelastography study

“…The authors concluded that on this basis a routine full blood count is indicated in preeclampsia, but not in patients who are HIV-positive, unless there are other comorbidities. 24 Davies et al evaluated differences in healthy pregnant versus preeclamptic women using the Platelet Function Analyzer (PFA-100) and TEG. This study found a mean MA of 73 mm, and that despite an abnormal clotting time in the preeclampsia cohort, the MA remained within the normal range.…”

Troubleshooting obstetric spinal anaesthesia at district hospital level

“…In an otherwise healthy parturient, HIV infection is not an indication for an FBC, as this does not confer increased risk of moderate thrombocytopaenia in the obstetric population. 10 …”

“…In an otherwise healthy parturient, HIV infection is not an indication for an FBC, as this does not confer increased risk of moderate thrombocytopaenia in the obstetric population. 10 Whilst patients with severe preeclampsia should be referred to regional hospitals, many patients with mild preeclampsia are managed at district-level hospitals, and occasionally will progress to severe disease requiring urgent management at district hospitals. The National Guidelines for Hypertension in Pregnancy should be followed.…”