Ma. Brown et al., MEASURING BLOOD-PRESSURE IN PREGNANT-WOMEN - A COMPARISON OF DIRECT AND INDIRECT METHODS, American journal of obstetrics and gynecology, 171(3), 1994, pp. 661-667
OBJECTIVES: Our goals were to determine (1) whether Korotkoff phase IV
or V sound was a more accurate measure of diastolic blood pressure in
pregnancy and (2) interobserver variability of mercury sphygmomanomet
ry of pregnant women. STUDY DESIGN: Direct (intraarterial) and indirec
t (mercury sphygmomanometry) blood pressures were compared in 28 pregn
ant women. Interobserver variability was assessed in a separate study
of 86 pregnant women using four highly trained observers. RESULTS: (1)
Routine sphygmomanometry underestimated direct systolic pressure by 1
1 (3, 18) mm Hg, p < 0.001 (median, interquartile range of differences
). Phase IV Korotkoff sound overestimated direct diastolic pressure by
9 (2, 12) mm Hg (p < 0.001) and phase V by 4 (2, 7) mm Hg (p = 0.04).
Phase V-recorded diastolic pressure was closer to direct diastolic pr
essure significantly more often (75%) than was phase IV-recorded diast
olic pressure (21%) (p = 0.003). Mean arterial pressures did not diffe
r significantly according to the method used. (2) Median blood pressur
es did not differ among the four observers for systolic, diastolic pha
se IV, or phase V recordings. Maximum difference for blood pressure re
cording among observers was 4 (2, 6) mm Hg. CONCLUSIONS: Auscultatory
sphygmomanometry in pregnant women underestimates systolic and overest
imates diastolic blood pressure, but the phase V Korotkoff sound is mo
re likely to represent the true diastolic pressure than is the phase I
V sound.