Accuracy of emergency physicians using ultrasound to determine gestational age in pregnant women.
BACKGROUND
Rapid and accurate determination of gestational age may be vital to the appropriate care of the critically ill pregnant patient. Before the use of emergency ultrasound, physical examination of fundal height (FH) in the nonverbal patient was considered the quickest method to estimate gestational age. We conducted a prospective, observational study of the performance of bedside sonography to determine gestational age.


METHODS
We enrolled a convenience sample of women in their second or third trimester of pregnancy. Emergency physicians (EPs) made ultrasound measurements of fetal biparietal diameter (BPD) and femur length, followed by a measurement of FH. These measurements were compared with true gestational age (TGA), sonography by an ultrasound technician, and measurement of FH performed by an obstetrician. Main outcome measures were the average time needed to complete measurements; correlation coefficients between EP measurements and those made by an ultrasound technician, an obstetrician, and TGA, and overall accuracy to determine fetal age greater than 24 weeks.


RESULTS
The average time to complete ultrasound measurements was less than 1 minute. When physician-performed measurements were compared with TGA, the correlation coefficients were 0.947 (0.926-0.968) for BPD, 0.957 (0.941-0.973) for femur length, and 0.712 (0.615-0.809) for FH. When determining fetal viability, EP's overall accuracy was 96% using ultrasound and 80% using FH.


CONCLUSIONS
With brief training, EPs can quickly and accurately determine gestational age using ultrasound, and these estimates may be more accurate than those obtained through physical examination. Emergency physicians should consider using ultrasound in emergent evaluation of pregnant patients who are unable to provide history.
Shah
Sachita
S
Department of Emergency Medicine, Alameda County Medical Center, Oakland, CA 94602, USA. sachita.shah@gmail.com
Teismann
Nathan
N
Zaia
Brita
B
Vahidnia
Farnaz
F
River
Gerin
G
Price
Dan
D
Nagdev
Arun
A
D000293:Adolescent; D000328:Adult; D000886:Anthropometry / Q000379:methods*; D002140:California; D002983:Clinical Competence / Q000592:standards*; D018568:Crown-Rump Length; D004635:Emergency Medicine / Q000193:education / Q000379:methods* / Q000592:standards; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005865:Gestational Age; D006784:Hospitals, Teaching; D006786:Hospitals, Urban; D006801:Humans; D009774:Obstetrics / Q000379:methods / Q000592:standards; D010808:Physical Examination / Q000379:methods; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000295:instrumentation / Q000379:methods* / Q000592:standards