Is one elevated blood pressure enough? A retrospective analysis of preeclampsia labs sent from the emergency room

Background: In the emergency department, where providing efficient, cost-effective medical care is becoming increasingly important, care of pregnant women with elevated blood pressures is varied. Currently, there are no recommendations designating when laboratory evaluation for preeclampsia should be initiated in the emergency department. Objective: This study sought to compare the incidence of positive laboratory findings in women with isolated initial versus repetitive elevated blood pressure in the emergency department. Study Design: This retrospective cohort included women ≥ 20 weeks gestation who presented to a tertiary care emergency department between January and July 2014 with an elevated blood pressure (≥ 140 mmHg systolic or ≥ 90 mmHg diastolic) and without significant co-morbidities (chronic hypertension, diabetes mellitus, preexisting renal or liver disease, or thrombocytopenia). The primary outcome was abnormal laboratory values suggesting preeclampsia (platelets, creatinine, liver enzymes, and urine protein/creatinine ratio). The association between one versus more than one elevated blood pressure in the emergency department and abnormal laboratory evaluation for preeclampsia was evaluated using Fisher’s exact test. Secondary outcomes included diagnoses of preeclampsia at emergency department discharge or delivery. Results: Of 4,208 charts screened, 271 met inclusion criteria and had complete preeclampsia labs sent per hospital policy. Of these, 122 had an isolated elevated blood pressure and 149 had more than one elevated blood pressure. Women with multiple elevated blood pressures were more likely to have abnormal preeclampsia labs than women with an isolated elevated blood pressure, 34.2% vs 15.6% (p<0.001). Only one woman with an isolated elevated blood pressure had a laboratory abnormality consistent with a severe feature of preeclampsia. Compared to women with an isolated elevated blood pressure, women with multiple elevated blood pressures were more likely to carry the diagnosis of preeclampsia at the time of discharge from the emergency department (14.8% vs 5.3%, p=0.003), and at the time of delivery (17.9% vs 4.2%, p<0.001). Conclusion: Women with multiple elevated blood pressures are at significantly higher risk for lab abnormalities consistent with preeclampsia and at significantly greater risk for developing preeclampsia by delivery than women with only one elevated blood pressure in the emergency department. Delaying serum laboratory evaluation for preeclampsia in patients presenting to the emergency department until two abnormal blood pressures are noted may be reasonable to decrease costs without significantly increasing morbidity. *Correspondence to: Martha B Kole, MD, 101 Dudley Street, Providence, RI 02905, USA, Tel: (401)247-1122; E-mail: mkole@wihri.org Received: June 17, 2019; Accepted: July 30, 2019; Published: August 02, 2019 Introduction Worldwide, 10% of pregnancies are complicated by hypertension leading to significant maternal and perinatal morbidity and mortality [1]. In the United States, the prevalence of preeclampsia has been increasing, rising from 3.4% in 1980 to 3.8% in 2010 [2,3]. Due to increasing incidence and potential for poor outcomes including preterm delivery, placental abruption, intrauterine growth restriction and perinatal mortality [4-6], healthcare providers should have a heightened awareness of hypertensive disorders in pregnancy. This heightened awareness, however, should not be at the cost of evidencebased assessment of patients with newly elevated blood pressures. The diagnosis of gestational hypertension and preeclampsia require the development of hypertension which is defined as a persistent systolic blood pressure (BP) of 140mm Hg or higher, or a diastolic BP of 90mm Hg or higher after 20 weeks gestation in women with previously normal blood pressure [1]. Blood pressures should be elevated on 2 or more occasions at least 4 hours apart. Recommendations from The American College of Obstetricians and Gynecologists (ACOG) Task Force on Hypertension in Pregnancy clearly state that a blood pressure reading should be taken at least 5 minutes after the patient has been in a relaxed sitting position and if the initial BP measurement is elevated it should be repeated after several minutes in attempt to eliminate spuriously elevated BP determinations [1]. Preeclampsia is differentiated from gestational hypertension by the presence of proteinuria or additional serum markers that may be present in more severe forms of the disease even in the absence of proteinuria. Currently there are no guidelines indicating when to perform a Kole MB (2019) Is one elevated blood pressure enough? A retrospective analysis of preeclampsia labs sent from the emergency room Clin Obstet Gynecol Reprod Med, 2019 doi: 10.15761/COGRM.1000259 Volume 5: 2-5 laboratory evaluation for preeclampsia in the emergency department, a setting in which waiting four hours for an additional elevated blood pressure is typically not feasible. Given a lack of data, in some emergency room settings, such as ours, ‘preclamsia labs’ (complete blood count, liver transaminases, serum creatinine, urinalysis and urine protein/ creatinine ratio) are sent after any elevated blood pressure reading that occurs once a woman has been sitting for more than 5 minutes. Due to this practice, many women are committed to a “preeclampsia workup” following an isolated elevated blood pressure reading often resulting in normal lab results and leading to increased hospital charges, longer length of stay and heightened patient anxiety. The objective of our study was to compare the rate of abnormal preeclampsia labs in women with isolated (only 1) versus repetitive (≥2) elevated blood pressures in the emergency department setting. Additionally, we sought to assess the rate of hypertensive disorders of pregnancy at the time of delivery in women with isolated compared to repetitive elevated blood pressures in the emergency department.