ASA Monitor 12 2017, Vol.81, 32.
According to a recent single-center study reporting on neuraxial anesthesia in parturients with platelet counts less than 100,000/mm3, which of the following is most likely true?
- (A) Preeclampsia was the most common etiology of a platelet count below 100,000/mm3.
- (B) Ten percent of parturients had a platelet count below 100,000/mm3.
- (C) Approximately 25 percent of patients with a platelet count below 100,000/mm3 received neuraxial anesthesia.
- (D) No spinal-epidural hematomas occurred.
Neuraxial anesthesia is a common technique for providing labor analgesia and anesthesia for cesarean delivery. However, concerns about the risk of spinal-epidural hematoma arise when offering this option to patients who are thrombocytopenic, defined in a recent study as having a platelet count below 100,000/mm3. Inconsistency in the literature remains as to the safe lower limit for platelet count before proceeding with neuraxial anesthesia. Therefore, the investigators in this retrospective, single-institution study evaluated the rate and cause of thrombocytopenia among parturients. They also combined their data with those of previously published reports to calculate an estimate of the upper 95 percent confidence limit for the risk of neuraxial hematomas in parturients.
Between 2009 and 2013, 20,244 parturients were cared for at the study institution, and 368 (1.8 percent) had platelet counts below 100,000/mm3. The most common etiology for a low platelet count was gestational thrombocytopenia. Of the women with thrombocytopenia, 256 parturients had platelet counts that were known to be low before decisions on neuraxial anesthesia placement were made, while 112 were only identified as having low platelet counts after placement. Overall, 70 percent of the patients with thrombocytopenia received neuraxial anesthesia. A total of 151 of 256 (59 percent) of those parturients with low platelet counts known prior to delivery and 105 of 112 (94 percent) with unknown predelivery thrombocytopenia underwent neuraxial anesthesia. Epidurals or combined spinal-epidurals were placed in approximately 60 percent of thrombocytopenic parturients who received neuraxial anesthesia; the others received spinal anesthesia.
None of the parturients undergoing neuraxial anesthesia placement in the setting of a low platelet count suffered neurological sequelae; no spinal-epidural hematomas were reported. The authors then combined their data with those of four additional studies that previously reported on neuraxial placement in parturients with thrombocytopenia to calculate a 95 percent risk estimate for spinal-epidural hematoma. The upper limit of the 95 percent confidence interval was 1.2 percent for the current study alone (256 parturients) and 0.4 percent when all cohorts were combined (755 parturients). Because of the small sample size, meaningful analysis of risk in patients with platelet counts below 50,000/mm3 was not possible.
In summary, the authors of this retrospective study reported no spinal-epidural hematomas among parturients with thrombocytopenia undergoing neuraxial anesthesia placement at their institution. These findings provide more information in what will hopefully be a growing body of literature looking to clarify the safe limits for neuraxial anesthesia placement in parturients with low platelet counts.
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Bernstein J, Hua B, Kahana M, Shaparin N, Yu S, Davila-Velazquez J . Neuraxial anesthesia in parturients with low platelet counts. Anesth Analg. 2016;123(1):165–167.