asamonitor.org8

With recent media attention on maternal deaths, it is no secret that the maternal mortality rate in the U.S. is an abysmal 26.4 per 100,000 live births as reported in 2015.1 Countries that we might consider our peers (e.g., United Kingdom, Germany, France, Canada, etc.) all have maternal mortality rates of less than 10 per 100,000 live births. Not only does the U.S. have the highest rate of any high-resource country, but it is the only country in the world outside of Afghanistan and Sudan where the rate is rising.2

The leading causes of maternal mortality differ greatly between low- versus high-resource countries, with hemorrhage, sepsis, obstructed labor and hypertension accounting for a larger proportion of deaths in low-resource countries.3

A systematic review of maternal deaths by the World Health Organization found venous thromboembolism (VTE) to be the cause in 14.9 percent of maternal deaths in high-resource countries versus approximately 2 percent in low-resource countries.4 In the U.S., VTE accounted for 9.1 percent of all deaths from 2011-14.5 The incidence of VTE is increasing over time in women hospitalized for delivery, as risk factors such as obesity, cesarean delivery, advanced maternal age and medical comorbidities increase.6

Grace H. Shih, M.D., is Professor, Department of Anesthesiology, and Director, Obstetric Anesthesia, University of Kansas Health System, Kansas City.

Molly Beth Cason, M.D., is Assistant Professor of Anesthesiology, University of Kansas Health System, Kansas City.

Regina Fragneto, M.D., FASA, is Professor of Anesthesiology and Division Chief of Obstetric Anesthesia, University of Kentucky Department of Anesthesiology, Lexington.

Venous Thromboembolism: A Very Preventable Cause of Maternal MortalityMolly Beth Cason, M.D.

Grace H. Shih, M.D.Committee on Obstetric Anesthesia

Regina Fragneto, M.D., FASACommittee on Obstetric Anesthesia

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Analyses of maternal deaths in the U.S. have found that pulmonary embolism, with implementation of pharma-cologic or mechanical thromboprophylaxis, is one of the most preventable causes of death.7 The U.K. has seen a dramatic decline in maternal deaths from VTE (18 deaths between 2006-08 compared to 41 deaths between 2003-05) after implementing processes to better identify at-risk women and adopting widespread use of thromboprophylaxis.8 The California Maternal Quality Care Collaborative (CMQCC) recognized that 40 percent of California maternal deaths were preventable, and the state has seen a 55 percent decline in maternal mortality since 2006 after developing state-wide outreach collaboratives and quality-improvement toolkits, one of which focuses on VTE.9 Armed with this knowledge, the physician anesthesi- ologist has a unique opportunity to improve outcomes in maternal health care, and the road map to do so is available free of charge. The Council on Patient Safety in Women’s Health Care includes ASA, the American Association of Nurse Anesthetists, American College of Obstetricians and Gynecologists (ACOG), Society for Obstetric Anesthesia and Perinatology (SOAP) and many other professional organizations with the vision of providing “safe health care for every woman.”10 The website safehealthcareforeverywoman.org has accessible patient safety bundles published by the National Partnership for Maternal Safety (NPMS) under the guidance of the Council on Patient Safety in Women’s Health Care. In addition, the website has tools aimed at reducing maternal morbidity and mortality. The bundles outline critical clinical practices that should be implemented on every maternity unit. The CMQCC also has a free toolkit, “Improving Health Care Response to Maternal Venous Thrombo- embolism,” available since March 2018 and consistent with the toolkit provided by the NPMS.11

The VTE patient safety bundle from the NPMS is divided into four sections:1. Readiness – Use standardized VTE risk-assessment tools

in every unit during outpatient prenatal care, antepartum hospitalization, hospitalization for birth and the post- partum period.

2. Recognition and Prevention – Use risk-assessment tools on all patients to identify those appropriate for thrombo- prophylaxis in addition to providing education to patients and health care providers.

3. Response – Use standardized recommendations in every unit for mechanical prophylaxis and dosing and timing of pharmacologic prophylaxis.

4. Reporting/Systems Learning – Review thromboembolic events for systems issues and protocol compliance, monitor process metrics and outcomes, and assess for complications.12

The NPMS Consensus Bundle on VTE addresses the differing recommendations for prophylaxis among the Royal College of Obstetricians and Gynaecologists (RCOG), ACOG and the American College of Chest Physicians. Commonly in the U.S., only women with the highest risk of VTE receive prophylaxis, which is in contrast to the U.K., where risk factor assessment is routinely performed for all parturients and a much greater percentage of women receive thromboprophylaxis. The resulting recommendations in the NPMS bundle advise administering prophylaxis to more women than is the current practice in the U.S., but fewer than indicated by the RCOG recommendations. The U.K. has an excellent track record of reducing maternal VTE, and the RCOG recommendations may prove superior in the future.

More frequent use of pharmacologic thromboprophylaxis for hospitalized parturients raises concern among anesthesiologists about the safety of neuraxial anesthesia. SOAP responded to this concern with the 2018 publication of a consensus statement addressing parturients receiving anticoagulants.13 This statement recognizes the elevated risk of VTE in pregnant and postpartum women in contrast to the very low incidence of spinal-epidural hematomas in pregnant women, including those receiving thromboprophylaxis. It summarizes studies on the altered pharmacokinetics of unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) in the pregnant population and provides guidance for the use of neuraxial anesthesia in ante-, intra- and postpartum patients receiving UFH and LMWH (Table 1, page 11). Included in the statement are decision aids for use in urgent and emergent situations. The 2018 American Society of Regional Anesthesia and Pain Medicine (ASRA) update and the app address the situation of the anticoagulated parturient for neuraxial block, suggesting that the guidelines be applied to parturients.14 Both the SOAP and ASRA statements agree that

Continued on page 10

The goal of the NPMS is adoption of its safety bundles by every birthing facility in the

U.S. As leaders in patient safety, physician anesthesiologists should participate in multidisciplinary teams to implement the bundles and reduce maternal mortality in our country.

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asamonitor.org10

Continued from page 9

consideration be given to performing neuraxial blockade in select situations where general anesthesia presents a greater risk than spinal epidural hematoma to the parturient. SOAP supports the use of both NSAIDs and low-dose thrombo- prophylaxis after epidural catheter removal for patients following cesarean delivery given the extensive clinical practice of using these medications together and benefit of reducing opioid use. Prior to catheter removal, it recommends avoiding NSAIDs if UFH or LMWH are being administered.13

The goal of the NPMS is adoption of its safety bundles by every birthing facility in the U.S.12 As leaders in patient safety, physician anesthesiologists should participate in multidisciplinary teams to implement the bundles and reduce maternal mortality in our country. These strong and evidence-based practice recommendations will likely result in the increased use of pharmacologic thromboprophylaxis in pregnant and postpartum patients but should not deter the continued use of safe neuraxial anesthesia. Multidisciplinary communication about anticoagulation status is crucial, and institutions should develop effective methods to communicate among services when patients receiving thromboprophylaxis may need delivery. By following the consensus statements of the NPMS and SOAP, we can bring about these safe and necessary changes to clinical practice. References:1. GBD 2015 Maternal Mortality Collaborators. Global, regional, and

national levels of maternal mortality, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet. 2016;388(10053):1775-1812.

2. Alliance for innovation on maternal health (AIM). Council on Patient Safety in Women’s Health Care website. https://safehealthcareforeverywoman.org/aim-program/. Last accessed February 6, 2019.

3. Hogan MC, Foreman KJ, Naghavi M, et al. Maternal mortality for 181 countries, 1980-2008: a systematic analysis of progress towards Millennium Development Goal 5. Lancet. 2010;375(9726):1609-1623.

4. Khan KS, Wojdyla D, Say L, Gulmezoglu AM, Van Look PF. WHO analysis of causes of maternal death: a systematic review. Lancet. 2006;367(9516):1066-1074.

5. Pregnancy mortality surveillance system. Centers for Disease Control and Prevention, U.S. Department of Health & Human Services website. https://www.cdc.gov/reproductivehealth/maternal infanthealth/pregnancy-mortality-surveillance-system.htm. Last updated August 7, 2018. Last accessed February 6, 2019.

6. Friedman AM, Ananth CV, Prendergast E, Chauhan SP, D’Alton ME, Wright JD. Thromboembolism incidence and prophylaxis during vaginal delivery hospitalizations. Am J Obstet Gynecol. 2015;212(2):221.e1-221.e12.

7. Clark SL, Belfort MA, Dildy GA, Herbst MA, Meyers JA, Hankins GD. Maternal death in the 21st century: causes, prevention, and relationship to cesarean delivery [published online May 2, 2008]. Am J Obstet Gynecol. 2008;199(1):36.e1-36.e5; discussion 91-32. e7-e11.

8. Cantwell R, Clutton-Brock T, Cooper G, et al. Saving mothers’ lives: reviewing maternal deaths to make motherhood safer: 2006-2008. The eighth report of the confidential enquiries into maternal deaths in the United Kingdom. BJOG. 2011;118 Suppl 1:1-203.

9. Main EK, Markow C, Gould J. Addressing maternal mortality and morbidity in California through public-private partnerships. Health Aff (Millwood). 2018;37(9):1484-1493.

10. Council on Patient Safety in Women’s Health Care website. https://safehealthcareforeverywoman.org/. Last accessed February 6, 2019.

11. Improving health care response to maternal venous thrombo-embolism. California Maternal Quality Care Collaborative website. https://www.cmqcc.org/resources-toolkits/toolkits/improving-health-care-response-maternal-venous-thromboembolism. Published 2018. Last accessed February 6, 2019.

12. D’Alton ME, Friedman AM, Smiley RM, et al. National partnership for maternal safety: consensus bundle on venous thromboembolism. Anesth Analg. 2016;123(4):942-949.

13. Leffert L, Butwick A, Carvalho B, et al; for members of the SOAP VTE Taskforce. The Society for Obstetric Anesthesia and Perinatology consensus statement on the anesthetic management of pregnant and postpartum women receiving thromboprophylaxis or higher dose anticoagulants. Anesth Analg. 2018;126(3):928-944.

14. Horlocker TT, Vandermeuelen E, Kopp SL, Gogarten W, Leffert LR, Benzon HT. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines (fourth edition). Reg Anesth Pain Med. 2018;43(3):263-309.

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Table 1: Timing of Neuraxial Block After Anticoagulation

Anticoagulant Antepartum/Intrapartum Postpartum

Low dose SQ UFH(5,000 U bid or tid)

Wait 4-6 hours after last dose or check aPTT (proceed if within normal range)

Wait 1 hour after neuraxial block placement and 1 hour after removal of epidural catheter to initiate or resume thromboprophylaxis

Indwelling catheters can be maintained with 5,000 U SQ bid UFH. Removal of catheter can occur 4-6 hours after last dose, and redosing can occur 1 hour after removal of the epidural catheter

Intermediate dose SQ UFH(7,500-10,000 U bid with total <20,000 U/day)

Wait 12 hours after last dose or check aPTT (proceed if within normal range)

Same as for low dose SQ UFH postpartum recommendations

High dose SQ UFH(>10,000 U/dose or total >20,000 U/day)

Wait 24 hours after last dose and check aPTT (proceed if within normal range)

Same as for low dose SQ UFH postpartum recommendations

Low dose SQ LMWH(enoxaparin 30 mg BID or <_ 40 mg qd)

Wait 12 hours after last dose Wait 12 hours after neuraxial block and 4 hours after removal of epidural catheter to initiate or resume thromboprophylaxis

Indwelling catheters can be maintained with low dose SQ LMWH. Removal of catheter can occur 12 hours after last dose, and redosing can occur 4 hours after removal of the epidural catheter

Intermediate dose LMWH(enoxaparin >40 mg qd or 30 mg bid and <1 mg/kg bid or 1.5 mg/kg qd)

No published data to recommend a specific interval between 12-24 hours after last dose

No data

High dose SQ LMWH(enoxaparin 1 mg/kg bid or 1.5 mg/kg qd)

Wait 24 hours after last dose Wait 24 hours after neuraxial block and 4 hours after removal of epidural catheter to initiate or resume thromboprophylaxis

Avoid therapeutic dosing with in situ epidural catheters

I.V. heparin Wait 4-6 hours after last dose and check aPTT (proceed if within normal range)

Same as for low dose SQ UFHpostpartum recommendations

UFH: unfractionated heparin

LMWH: low molecular weight heparin

The risk of spinal epidural hematoma associated with placement of the neuraxial block should be balanced against the risks of general anesthesia, taking into consideration co-existing conditions and urgency of the clinical scenario.

Use of NSAIDS along with anticoagulants while an epidural catheter is in place can increase the risk of bleeding complications.

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