A review of the records of more than 20,000 women in labor has found that even those with platelet counts as low as 50×109/L can safely receive regional anesthesia (RA), under the right circumstances. Although RA is now the standard of care in laboring women, turning to epidurals and spinals in high-risk parturients—especially those with low platelet counts—can be discomfiting.
“On our labor floor, often we have patients with platelet counts less than 100,000,” said Jeffrey Bernstein, MD, assistant professor of anesthesiology as well as assistant professor of obstetrics, gynecology, and women’s health at Yeshiva University’s Albert Einstein College of Medicine, in New York City. “Because we have many high-risk OB [obstetrical] patients at our tertiary care center [Montefiore Medical Center], I wanted to see what our actual incidence of thrombocytopenia was, and what we’ve done in the past with respect to placing epidurals in these women.”
Dr. Bernstein and his colleagues used a hospital database management program to identify 20,244 women who delivered at the hospital between September 2009 and 2013. A detailed chart review was then performed for 256 women (1.3%) who had platelet counts of 100×109/L or lower at preanesthetic assessment. Metrics included the etiology of thrombocytopenia, type of anesthetic technique, mode of delivery, major neurologic and anesthetic complications, and body mass index (BMI).
The review found that 151 of the 256 women (59%) received RA. A total of 175 patients had platelet counts between 80×109/L and 100×109/L (mean BMI, 31.37±5.65 kg/m2); of these, 131 (75%) received RA: 89 epidural, 37 spinal and five combined spinal–epidural. “Between 80,000 and 100,000 platelets, physicians felt pretty comfortable about placing a neuraxial anesthetic,” Dr. Bernstein noted.
In 76 patients (mean BMI, 31.41±4.94), platelet counts were 50×109/L to 79×109/L; 19 of these women (25%) received RA: 10 epidural and nine spinal. “In the patient group with platelets between 50,000 and 79,000, most had either stable or static situations, meaning idiopathic thrombocytopenic purpura [ITP] or gestational thrombocytopenia where the platelets are not being consumed,” he added.
“These patients are the big question for me,” Dr. Bernstein commented. “I mean, I can run across the highway 19 times and not get hit by a car. Does that mean it’s safe? Personally, I feel pretty comfortable with a count over 60,000 in patients with ITP or gestational thrombocytopenia that show no sign of abnormal bruising or bleeding, when I suspect that the platelet function is normal. If you have that with preeclampsia, the platelets can be abnormally functioning, but there may be an ongoing dynamic process where platelets might be consumed actively. The platelet count of 115,000 at 7 o’clock in the morning could drop to 80,000 by 2 o’clock in the afternoon.”
Finally, 13 patients had platelet counts less than 50×109/L, one of whom (mean BMI, 35.82±10.20) had an epidural. No neurologic complications occurred in any patient.
“It’s important to remember that the risk of hematoma exists when the catheters are being removed as well,” he said. “Taking the epidural out is just as risky as putting it in, so you want the same platelet count that you were comfortable with when placing the catheter. I recently put a catheter in a patient who had a count of 89,000. After she delivered, it was 69,000, so I left the catheter in. We took another count and it was 64,000; we still left it in. Once her count bumped back up again, then we took it out, 36 hours after she arrived at the ward.”
Bupesh Kaul, MD, clinical associate professor of anesthesiology at the University of Pittsburgh, helped trace the history of neuraxial anesthesia use in laboring women. “In the early 1990s, the people were very uncomfortable putting in epidurals in patients with a platelet count below 100,000,” he told Anesthesiology News. “Sometime thereafter, we realized that the absolute platelet count number didn’t mean much.
“Since then, the effort really has been to better predict the risk of bleeding in the epidural space,” he continued. “Since the early 2000s, the thromboelastogram has been used more and more, and seems to predict platelet function better than absolute platelet count. The thromboelastogram has allowed us to be much more comfortable at lower absolute platelet counts than was possible before.” Assessing clinical symptoms, such as bleeding from the gums, petechiae and bleeding from venipuncture sites is an important adjunct in determining the safety of neuraxial anesthesia in these patients, he added.