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Dive into the research topics where John R. Barton is active.

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Featured researches published by John R. Barton.


Obstetrics & Gynecology | 2008

Prediction and prevention of recurrent preeclampsia

John R. Barton; Baha M. Sibai

Women with a history of previous preeclampsia are at increased risk of preeclampsia and other adverse pregnancy outcomes in subsequent pregnancies. The magnitude of this risk is dependent on gestational age at time of disease onset, severity of disease, and presence or absence of preexisting medical disorders. The objective in the management of these patients is to reduce risk factors by optimizing maternal health before conception and to detect obstetric complications as early as possible. This objective can be achieved by formulating a rational approach that includes preconception evaluation and counseling, early antenatal care, frequent monitoring of maternal and fetal well-being, and timely delivery. First-trimester ultrasound examination is essential for accurate dating and establishing fetal number. Laboratory studies are obtained to assess the function of different organ systems that are likely to be affected by preeclampsia and to establish a baseline for future assessment. Recent studies have confirmed that there is no single biomarker that can be clinically useful for the prediction of recurrent preeclampsia. Combinations of biomarkers and biophysical parameters appear promising, but more data are needed to confirm their use in clinical practice. Supplementation with fish oil, calcium, or vitamin C and E and the use of antihypertensives have been shown to be ineffective in the prevention of recurrent preeclampsia and are not recommended. Supplementation with low-dose aspirin may be offered on an individualized basis. Because women with previous preeclampsia are at increased risk for adverse pregnancy outcomes (preterm delivery, fetal growth restriction, abruptio placentae, and fetal death) in subsequent pregnancies, we recommend more frequent monitoring for signs and symptoms of severe hypertension or preeclampsia than that recommended for normal pregnancy. This monitoring may include more frequent prenatal visits, home blood pressure monitoring, or nursing contacts. For patients with a prior pregnancy complicated by preeclampsia with fetal growth restriction, we recommend serial ultrasound evaluation of fetal growth and amniotic fluid volume. The development of severe gestational hypertension, fetal growth restriction, or recurrent preeclampsia requires maternal hospitalization.


American Journal of Obstetrics and Gynecology | 1991

Maternal plasma level of endothelin is increased in preeclampsia

Alfredo Nova; Baha M. Sibai; John R. Barton; Brian M. Mercer; Murray D. Mitchell

Endothelin is a potent vasoconstrictor that is reportedly increased in conditions characterized by endothelial damage. Maternal plasma endothelin levels were compared between 27 women with preeclampsia (23 without and 4 with the hemolysis, elevated liver enzymes, and low platelet count syndrome) and 14 women with normotensive pregnancies. The mean +/- SEM plasma endothelin values were significantly higher in patients with preeclampsia uncomplicated by the hemolysis, elevated liver enzymes, and low platelet count syndrome (5.48 +/- 0.30 fmol/ml vs 3.86 +/- 0.28, p less than 0.001). In addition, the preeclamptic group with the hemolysis, elevated liver enzymes, and low platelet count syndrome had significantly higher endothelin levels than those without the syndrome (8.30 +/- 1.62 fmol/ml vs 5.48 +/- 0.30, p less than 0.05). There was no correlation between plasma endothelin values and either systolic or diastolic blood pressure. We conclude that plasma endothelin levels are significantly increased in women with preeclampsia and particularly in those with the hemolysis, elevated liver enzymes, and low platelet count syndrome, suggesting an association with widespread endothelial damage.


Obstetrics & Gynecology | 1994

Late Postpartum Eclampsia Revisited

Suzanne L. Lubarsky; John R. Barton; Steven A. Friedman; Souha Nasreddine; Mohammed K. Ramadan; Baha M. Sibai

Objective: To describe the clinical and neurologic findings in patients with late postpartum eclampsia (convulsions beginning more than 48 hours, but less than 4 weeks, after delivery). Methods: This study evaluated all patients with the diagnosis of late postpartum eclampsia managed at our institution between August 1977 and July 1992. Results: There were 54 cases of late postpartum eclampsia among a total of 334 cases of eclampsia during the study period. Late postpartum eclampsia constituted 56% of total postpartum eclampsia and 16% of all cases of eclampsia. Convulsions began from postpartum days 3‐23 (mean 6). Thirty women (56%) had been identified as preeclamptic before their convulsions. A history of either severe headache or visual disturbances before convulsion was elicited in 83% of the patients. During the study period, eight women not included in the study group had late postpartum seizures attributed to other causes. Conclusions: Severe headache or visual disturbance frequently antedates late postpartum eclampsia. Only eight of 62 patients with late postpartum seizures had identifiable etiologies other than eclampsia. (Obstet Gynecol 1994;83:502‐5)


American Journal of Obstetrics and Gynecology | 1994

Acute fatty liver of pregnancy: An experience in the diagnosis and management of fourteen cases

Ihab M. Usta; John R. Barton; Erol Amon; Anthony Gonzalez; Baha M. Sibai

OBJECTIVE Our purpose was to investigate the diagnostic problems and maternal-perinatal outcome in cases of acute fatty liver of pregnancy. STUDY DESIGN Fourteen cases with acute fatty liver of pregnancy managed during the past 8-years were studied with emphasis on presenting symptoms, admitting diagnosis, laboratory findings, clinical course, maternal complications, and neonatal outcome. RESULTS The mean gestational age at onset was 34.5 weeks (range 28 to 39). Only seven patients had acute fatty liver of pregnancy as a definite or suspected diagnosis on admission. Computed tomography of the liver was performed on 10 patients, with only two positive results. There were no maternal deaths; however, maternal morbidity was frequent: four patients had hepatic encephalopathy, three pulmonary edema, three ascites, four respiratory arrest, two diabetes insipidus, and 10 had transfusion of blood or blood products to correct either disseminated intravascular coagulation or excessive bleeding. Coagulation abnormalities were common: hypofibrinogenemia (< 300 mg/dl) in 13 patients (93%), prolonged prothrombin time in 12 (86%), and prolonged partial thromboplastin time in 11 (79%). The corrected perinatal mortality was 6.6%. CONCLUSION Acute fatty liver of pregnancy should be suspected in all patients with symptoms of preeclampsia in the presence of hypoglycemia, low fibrinogen, and prolonged prothrombin time, particularly in the absence of severe abruptio placentae. Computed tomography of the liver has a high false-negative rate in patients with acute fatty liver of pregnancy. In spite of the literatures dismal prognosis, our findings indicate that maternal and perinatal outcomes appear favorable in well-managed patients.


American Journal of Obstetrics and Gynecology | 1996

Hepatic imaging in HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count)

John R. Barton; Baha M. Sibai

OBJECTIVES Our objective was to describe the hepatic imaging findings in selected patients with HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) and to correlate these findings with the severity of concurrent clinical and laboratory abnormalities. STUDY DESIGN Patients with laboratory criteria for HELLP syndrome with complaints of severe right upper quadrant abdominal pain in association with either shoulder pain, neck pain, or relapsing hypotension underwent imaging of the liver. Clinical and laboratory parameters were then correlated with the hepatic imaging findings. RESULTS Thirty-four patients were evaluated in this study. Computed tomographic scanning of the liver was used for 33 patients. Additional imaging evaluations included magnetic resonance imaging for 4 patients and ultrasonographic evaluation of the liver for 5 patients. In 15 cases (45%) the computed tomographic results were abnormal. The most frequent abnormal hepatic imaging findings were subcapsular hematoma (n = 13) and intraparenchymal hemorrhage (n = 6). There was no statistically significant correlation between the presence of an abnormal hepatic imaging finding and the severity of liver function test abnormalities. However, the severity of thrombocytopenia did correlate with hepatic imaging findings (p = 0.04). In particular, an abnormal hepatic imaging finding was noted for 10 of 13 patients (77%) with a platelet count of < or = 20 x 10(9)/L (p = 0.012). CONCLUSIONS Abnormalities in liver function test results do not accurately reflect the presence of abnormal hepatic imaging findings in HELLP syndrome. Patients with HELLP syndrome having complaints of right upper quadrant pain and neck pain, shoulder pain, or relapsing hypotension should undergo imaging of the liver.


American Journal of Obstetrics and Gynecology | 2008

Peripartum cardiomyopathy: prognostic factors for long-term maternal outcome

Mounira Habli; Thomas O'Brien; Elizabeth Nowack; Saeb Khoury; John R. Barton; Baha M. Sibai

OBJECTIVE The objective of the study was to assess the prognostic value of ejection fraction (EF) at index and subsequent pregnancy on long-term outcome in patients with peripartum cardiomyopathy (PPCM). STUDY DESIGN Seventy PPCM patients met inclusion criteria. Patients had echocardiography evaluations at the index pregnancy, at interval follow-up (F/U) or at the beginning of a subsequent pregnancy and the last F/U study available. Outcome data were echocardiographic parameters and the subsequent need for cardiac transplant. RESULTS Patients were categorized on the basis of their initial EF into EF of 25% or less and EF greater than 25% and stratified on the basis of their pregnancy into the following groups: group 1 (n = 33), no subsequent pregnancy; group 2 (n = 16), subsequent pregnancy with early termination; and group 3 (n = 21), successful subsequent pregnancy. F/U from index pregnancy to final F/U was 3.4+/-1.9 (range, 1-6 years). Groups 1 and 2 had persistent left ventricular dysfunction at all echocardiographic evaluations. In group 3, despite a mean EF greater than 40% at a subsequent pregnancy, 29% had worsening cardiac symptoms. Among 28 patients with EF of 25% or less, 16 (57%) had end-stage cardiac disease. One had a transplant and 15 were on a transplant list. All 16 had a baseline EF 25% or less at index pregnancy: 4 had improved (EF greater than 40%) at interval F/U and 3 at last F/U available. CONCLUSION Women with a history of PPCM had a higher rate of progression of symptoms of heart failure in a subsequent pregnancy. A baseline left ventricular EF 25% or less at index pregnancy is associated with a higher rate of cardiac transplant.


American Journal of Obstetrics and Gynecology | 2015

Center of excellence for placenta accreta

Robert M. Silver; Karin A. Fox; John R. Barton; Alfred Abuhamad; Hyagriv N. Simhan; C. Kevin Huls; Michael A. Belfort; Jason D. Wright

Placenta accreta spectrum is one of the most morbid conditions obstetricians will encounter. The incidence has dramatically increased in the last 20 years. The major contributing factor to this is believed to be the increase in the rate of cesarean delivery. Despite the increased incidence of placenta accreta, most obstetricians have personally managed only a small number of women with placenta accreta. The condition poses dramatic risk for massive hemorrhage and associated complication such as consumption coagulopathy, multisystem organ failure, and death. In addition, there is an increased risk for surgical complications such as injury to bladder, ureters, and bowel and the need for reoperation. Most women require blood transfusion, often in large quantities, and many require admission to an intensive care unit. As a result of indicated, often emergent preterm delivery, many babies require admission to a neonatal care intensive care unit. Outcomes are improved when delivery is accomplished in centers with multidisciplinary expertise and experience in the care of placenta accreta. Such expertise may include maternal-fetal medicine, gynecologic surgery, gynecologic oncology, vascular, trauma and urologic surgery, transfusion medicine, intensivists, neonatologists, interventional radiologists, anesthesiologists, specialized nursing staff, and ancillary personnel. This article highlights the desired features for a center of excellence in placenta accreta, and which patients should be referred for evaluation and/or delivery in such centers.


Obstetrics & Gynecology | 1997

Septic shock in pregnancy

William C. Mabie; John R. Barton; Baha M. Sibai

Objective To evaluate the etiology, management, and maternal and perinatal outcome in patients with septic shock during pregnancy. Methods In 18 patients with spetic shock during pregnancy, the criteria for the diagnosis were sepsis-induced hypotension unresponsive to adequate fluid resuscitation and requirement for vasopressors. Results Causes of shock were pyelonephritis (n = 6), choriomnionitis (n = 3), postpartum endometritis (n = 2), toxic shock (n = 2), and one each of septic abortion, ruptured appendix, ruptured ovarian abscess, necrotizing fasciitis, and bacterial endocarditis. Five women (28%) died. Comparing medians of the initial laboratory data for the 13 survivors with those of the five nonsurvivors revealed significant differences for hematocrit (26 compared with 35%; Z = −2.267, P = .023), aspartate aminotransferase (30 compared with 287 U/L; Z = −2.068, P = .042), total bilirubin (1.6 compared with 5.8 mg/dL; Z = 2.046, P = .045), arterial carbon dioxide pressure (30 compared with 19 mmHg; Z = −2.384, P = .013), and arterial oxygen pressure (62 compared with 104 mmHg; Z = −2.004, P = .048). Comparing medians of the hemodynamic data showed differences in blood pressure (88 compared with 70 mmHg; Z = −2.439, P = .013), stroke volume (74 compared with 52 mL; Z = −2.041, P = .038), and left ventricular stroke work index (42 compared with 12 g · m · m2; Z = −1.929, P = .052). Sixty-four percent of survivors and 80% of nonsurvivors had depressed left ventricular function (Fisher exact test, P > .99). Locating the source of infection was difficult and delayed in eight patients. Conclusion In women with septic shock, progression to death can be dramatically rapid. Because vascular permeability is increased, it may be appropriate to administer vasopressors early during resuscitation. An initial low cardiac output is a poor prognostic sign.


Obstetrics & Gynecology | 2014

The national partnership for maternal safety

Peter S. Bernstein; Martin Jn; John R. Barton; Laurence E. Shields; Maurice L. Druzin; Barbara M. Scavone; Jennifer Frost; Christine H. Morton; Catherine Ruhl; Joan Slager; Eleni Z. Tsigas; Sara Jaffer; M. Kathryn Menard

Recognition of the need to reduce maternal mortality and morbidity in the United States has led to the creation of the National Partnership for Maternal Safety. This collaborative, broad-based initiative will begin with three priority bundles for the most common preventable causes of maternal death and severe morbidity: obstetric hemorrhage, severe hypertension in pregnancy, and peripartum venous thromboembolism. In addition, three unit-improvement bundles for obstetric services were identified: a structured approach for the recognition of early warning signs and symptoms, structured internal case reviews to identify systems improvement opportunities, and support tools for patients, families, and staff that experience an adverse outcome. This article details the formation of the National Partnership for Maternal Safety and introduces the initial priorities.


American Journal of Obstetrics and Gynecology | 2008

Expectant management of severe preeclampsia at less than 27 weeks' gestation: maternal and perinatal outcomes according to gestational age by weeks at onset of expectant management

Annette Bombrys; John R. Barton; Elizabeth Nowacki; Mounira Habli; Leeya Pinder; Helen How; Baha M. Sibai

OBJECTIVE The objective of the study was to determine perinatal outcome and maternal morbidities based on gestational age (GA) at the onset of expectant management in severe preeclampsia at less than 27 weeks. STUDY DESIGN This was a retrospective analysis of outcome in patients with severe preeclampsia. Forty-six patients (51 fetuses) with severe preeclampsia at less than 27 weeks were studied. Corticosteroids were administered beyond 23 weeks. Perinatal and maternal complications (a composite maternal morbidities including HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, pulmonary edema, eclampsia, and renal insufficiency were analyzed. RESULTS Four patients had multifetal gestations (1 triplet, 3 twins). Median days of prolongation was 6 (range 2-46). Overall perinatal survival was 29 of 51 (57%). Birthweights of 27 (53%) were less than 10%, and 18 (35%) were less than 5%. There were no perinatal survivors in those with a GA less than 23 weeks, at 23 to 23 6/7 weeks, 2 of 10 (20%) survived, and both reached 26 weeks at delivery. For those at 24 to 24 6/7, 25 to 25 6/7, and 26 to 26 6/7 weeks, the perinatal survival rates were 5 of 7 (71%), 13 of 17 (76%), and 9 of 10 (90%), respectively; but rates of respiratory complications were high. There were no maternal deaths, but overall maternal morbidity was 21 of 46 (46%), but was 9 of 14 (64%) in those at less than 24 weeks. CONCLUSION Perinatal outcome in severe preeclampsia in the midtrimester is dependent on GA at onset of expectant management and GA at delivery. Given the high maternal morbidity and extremely low perinatal survival in expectant management at less than 24 weeks, termination of pregnancies should be offered after extensive counseling.

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Baha M. Sibai

University of Texas Health Science Center at Houston

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Gary Stanziano

University of California

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Debbie Rhea

University of Kentucky

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Mounira Habli

Cincinnati Children's Hospital Medical Center

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Douglas A. Milligan

Baptist Memorial Hospital-Memphis

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Baha Sibai

Thomas Jefferson University

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Brian M. Mercer

University of Tennessee Health Science Center

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Debbie Jacques

University of Cincinnati

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