Objectives: To assess the hydration status of women presenting to an E
D with hyperemesis gravidarum and to determine whether clinically rele
vant changes in orthostatic vital signs occur. Methods: A convenience
sample of 23 pregnant women who had hyperemesis gravidarum, with each
patient serving as her own control. The study took place in the ED obs
ervation unit of an urban teaching hospital. Women who had pregnancies
of less than or equal to 16 weeks' gestation who had been vomiting fo
r at least 24 hours were included. Supine and standing pulse rates and
blood pressures (BPs) were measured sequentially after 5 minutes in e
ach position. Patient weight and urine specific gravity (SG) also were
recorded. After 6 L of lactated Ringer's solution was infused over a
12-hour period, the same measurements were repeated. Pre- and posthydr
ation changes were analyzed using the paired t-test. Results: The mean
treatment weight gain as a percentage of the total body weight was 5.
6% +/- 2.2% (mean +/- SD). The urine SG decreased from 1.027 +/- 0.004
to 1.008 +/- 0.003 (p < 0.001). The mean change in systolic BP upon a
ssuming the standing position was -8.3 +/- 12.7 mm Hg before hydration
vs 2.9 +/- 7.8 mm Hg after hydration (p < 0.001). The corresponding c
hange in mean diastolic BP was 3.7 +/- 10.9 mm Hg before hydration vs
8.6 +/- 10.9 mm Hg after hydration (p = 0.12). The mean change in puls
e rate upon standing was 26.8 +/- 14.5 beats/min before hydration vs 1
4.5 +/- 10.1 beats/min after hydration (p = 0.002). Conclusions: Women
who present to the ED with hyperemesis gravidarum are significantly d
ehydrated and experience measurable improvement in postural pulse rate
and systolic BP changes with rehydration. However, the presenting ort
hostatic changes lack sufficient sensitivity to be effectively used as
quantitative screening tests for dehydration.