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Superior Mesenteric Artery Flow Velocity Waveforms in Small for Gestational Age Fetuses Eleanor Hoon Joo Rhee Yale University

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Superior Mesenteric Artery Flow Velocity Waveforms in Small for Gestational Age Fetuses Eleanor Hoon Joo Rhee Yale University Yale University EliScholar – A Digital Platform for Scholarly Publishing at Yale Yale Medicine Thesis Digital Library School of Medicine 1998 Superior mesenteric artery flow velocity waveforms in small for gestational age fetuses Eleanor Hoon Joo Rhee Yale University Follow this and additional works at: http://elischolar.library.yale.edu/ymtdl Part of the Medicine and Health Sciences Commons Recommended Citation Rhee, Eleanor Hoon Joo, "Superior mesenteric artery flow velocity waveforms in small for gestational age fetuses" (1998). Yale Medicine Thesis Digital Library. 3064. http://elischolar.library.yale.edu/ymtdl/3064 This Open Access Thesis is brought to you for free and open access by the School of Medicine at EliScholar – A Digital Platform for Scholarly Publishing at Yale. It has been accepted for inclusion in Yale Medicine Thesis Digital Library by an authorized administrator of EliScholar – A Digital Platform for Scholarly Publishing at Yale. For more information, please contact [email protected]. YALE UNIVERSITY CUSHINGAVHITNEY MEDICAL LIBRARY Permission to photocopy or microfilm processing of this thesis for the purpose of individual scholarly consultation or reference is hereby granted by the author. This permission is not to be interpreted as affecting publication of this work or otherwise placing it in the public domain, and the author reserves all rights of ownership guaranteed under common law protection of unpublished manuscripts. Digitized by the Internet Archive in 2017 with funding from The National Endowment for the Humanities and the Arcadia Fund https://archive.org/details/superiormesenterOOrhee Superior Mesenteric Artery Flow Velocity Waveforms in Small for Gestational Age Fetuses A Thesis Submitted to the Yale University School of Medicine in Partial Fulfillment of the Requirements for the Degree of Doctor of Medicine by Eleanor Hoon Joo Rhee Year of degree 1998 Med LM : i iy 3 fYi'i S07 ¥AtF MFOTCM WARY AUG 1 8 1998 Superior Mesenteric Artery Flow Velocity Waveforms In Small For Gestational Age Fetuses Eleanor H.J. Rhee, Laura Detti, and Giancarlo Mari Departments of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut Abstract The objective of this study was to analyze the superior mesenteric artery flow velocity waveforms in small-for-gestational-age fetuses, and to compare its contribution to the management of these fetuses with that already provided by the middle cerebral artery and umbilical artery flow velocity waveforms. Middle cerebral artery, umbilical artery, and superior mesenteric artery flow velocity waveforms were prospectively obtained in 41 small-for-gestational-age fetuses with color Doppler ultrasonography. The pulsatility index was used to quantify the waveforms. Poor perinatal outcome was defined by fetal distress, perinatal death, need for assisted ventilation, and necrotizing enterocolitis. In the small-for- gestational-age fetuses the middle cerebral artery pulsatility index was abnormal in 22/41; the umbilical artery in 26/41; and the superior mesenteric artery in 17/41. Coincident with abnormal umbilical and middle cerebral artery flow velocity waveforms were greater occurrences of poor perinatal outcome. The abnormality of an increased pulsatility index in the superior mesenteric artery velocity waveforms of small-for-gestational-age fetuses suggests greater vascular resistance and an overall reduction in visceral perfusion. However, the study of the superior mesenteric artery seemed only to support the information already provided for by the middle cerebral and umbilical arteries. Acknowledgments For me to have begun on this path that others have treaded, I must acknowledge the sources that funded my quest into research. Initially I began my endeavors at NIH, as a recipient of the NIH Summer Intramural Research Training Award. I was immersed in the world of genetics and PCR as I studied the heterozygous expression of congenital adrenal hyperplasia in rats. Having returned to Yale satisfying my inclination for basic science research, I had a new desire for a more clinical project in the field of my future aspirations. Obstetrics and Gynecology. Yale kindly funded my work throughout medical school, including the two extra years I stayed in New Haven as I opted to continue with my numerous research projects and other pursuits. All my work has been involved with questions in the obstetrical field, except for one project that was in conjunction with the Neurology Department. It was through both these interactions that I was able to acquire the skills necessary for my conducting and understanding the resultant data from ultrasound and Doppler systems. My work was very much directed by Giancarlo Mari, MD. Since meeting him during my second year of medical school in 1993, I not only developed skills in assessing the fetal and maternal condition: I was given a mentor who supported me and always had faith that I would succeed and ultimately become what I always wanted to be when I grew up, an obstetrician/gynecologist. With his help I have my first publication in the Journal of Maternal-Fetal Medicine, hopefully the first of many. Along with Dr. Mari's guidance I must thank Tulin Oczan, MD and Laura Detti, MD. The value of friendship has been priceless but the hours spent with Tulin in helping me with my statistical analysis and with Laura in making my figures and boxes will never be forgotten. The atmosphere and camaraderie in the office while just doing one more Fisher analysis was a blessing in the wee hours, as I struggled to get the work in by the deadline. As I recount my supporters throughout this thesis I must acknowledge those who have helped me with the rigors and heartache of medical school. I can honestly say that my years at Yale have been my hardest but these have also been the years in which I have grown up the most and learned life's greatest lessons. I must give first billing to my parents, Sung Mi Rhee and Dr. TIang Yul Rhee. Without them I would not be here; I still find it important to state the obvious. I thank you both for always telling me that I was a "good egg" and pushing me forward. 1 am also indebted to Brian Kim. Without your incredible patience and belief in me I would have lost my vision. In part because of you I have a sense of my worth beyond the M.D. on a piece of paper, and have learned what it is that I need in my life. I also extend my love and gratefulness to my friends who are my family. Jane, Monica, Karen - I made it. Each of your contributions is too vast to be listed. But know that my being here is very much because of all of you. Thanks to Javier, Joshua, and Christopher. Javier for the notes and Java chip, Joshua for his computer expertise, and Chris for the late-night pep talks. There are many others who have seen me through my struggles like Dean Gifford and Cindy Andrien. If I have forgotten anyone, I apologize now and extend all my heartfelt thanks. TABLE OF CONTENTS Pages 1. Introduction 1-16 2. Statement of Purpose 17 3. Materials and Methods 18 - 23 4. Results 24 - 28 Table I. 26 Table II. 27 Table III. 28 5. Discussion 29 - 32 6. References 33 - 36 7. Bibliography of Other Works 37 1 INTRODUCTION Since the advent of ultrasound in the 1950s, it has become a highly developed technology which has become quite useful in prenatal diagnosis and fetal surveillance. Besides detecting structural and functional abnormalities, fetal size, and gestational age, ultrasound has helped guide physicians in their care of the female patient. The limitations of classic x-rays have been overcome with this imaging approach, and the need for the fetus to be exposed to radiation has been virtually eliminated. As ultrasound aids in the managing of pregnancy, certain areas for which this technology may be of benefit to the female patient are: 1 1. Estimation of gestational age for patients with uncertain clinical dates, or verification of dates for patients who are to undergo scheduled elective repeat cesarean delivery, indicated induction of labor, or other elective termination of pregnancy. Ultrasonographic confirmation of dating permits proper timing of cesarean delivery or labor induction to avoid premature delivery. 2. Evaluation of fetal grozuth (e.g., when the patient has an identified etiology for uteroplacental insufficiency, such as severe pre-eclampsia, chronic hypertension, chronic renal disease, severe diabetes mellitus, or for other medical complications of pregnancy where fetal malnutrition, i.e., IUGR or macrosomia, is suspected). Following fetal growth permits assessment of the impact of a complicating condition on the fetus and guides pregnancy management. 3. Vaginal bleeding of undetermined etiology in pregnancy. Ultrasound often allows determination of the source of bleeding and status of the fetus. 4. Determination of fetal presentation when the presenting part cannot be adequately determined in labor or the fetal presentation is variable in late pregnancy. Accurate knowledge of presentation guides management of delivery. 5. Suspected multiple gestation based upon detection of more than one fetal heart beat pattern, or fundal height larger than expected for dates, and/or 2 prior use of fertility drugs. Pregnancy management may be altered in multiple gestation. 6. Adjunct to amniocentesis. Ultrasound permits guidance of the needle to avoid the placenta and fetus, to increase the chance of obtaining amniotic fluid, and to decrease the chance of fetal loss. 7. Significant uterine size/clinical dates discrepancy. Ultrasound permits accurate dating and detection of such conditions as oligohydramnios and polyhydramnios, as well as multiple gestation, IUGR, and anomalies. 8. Pelvic mass detected clinically. Ultrasound can detect the location and nature of the mass and aid in diagnosis. 9. Suspected hydatidiform mole on the basis of clinical signs of hypertension, proteinuria, and/or the presence of ovarian cysts felt on pelvic examination or failure to detect fetal heart tones with a Doppler ultrasound device after 12 weeks.
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