Non-invasive Versus Invasive Blood Pressure Measurement in the Morbidly Obese Parturient With Severe Preeclampsia

A morbidly obese [Body Mass Index (BMI) ≥ 40 kg/m2] pregnant woman is at singular risk for
all the complications of pregnancy, most notably preeclampsia (PE). Furthermore a woman who
is already chronically hypertensive is likely to develop superimposed PE . Uncontrolled
systolic hypertension in pregnancy prompts placental abruption, hemorrhagic stroke, and
systolic or diastolic heart failure. Accurate blood pressure measurement is therefore a
prerequisite to controlling dangerously high systolic blood pressure (SBP) to enable labor
and delivery to be conducted safely in association with PE. Precise SBP measurement is also a
precondition for clinically testing hypotheses concerning the existence of druggable targets
that will allow prolongation of pregnancy in the face of severe PE and /or intra-uterine
growth restriction (IUGR) remote from term.

Oscillometric noninvasive blood pressure (NIBP) measurement is the customary standard blood
pressure monitoring method most often used in the labor suite and obstetric operating room
today. For this purpose a rectangular, cylindrical blood pressure (BP) cuff placed on the
upper arm is connected to an oscillometric blood pressure device. Yet inaccuracies related to
the fact that oscillometric NIBP devices under-read high SBP relative to IBP measurements
have been recognized as a potential source of maternal morbidity for years.

The study will compare IBP readings obtained from morbidly obese, severely hypertensive (SBP
> 160 mm Hg) parturients with NIBP consecutively measured with new innovative conical
Ultracheck Curve BP cuffs and large standard upper arm rectangular cylindrical BP cuffs.

Inclusion Criteria:

- Written, signed and dated informed consent

- ≥ 18 years of age

- BMI >40 kg/m2

- Has a clinically indicated radial artery line already in situ or who agree to
placement of an arterial line

- Systolic blood pressure >160 mm Hg

- Gestational age greater than or equal to 24 weeks

- Parturients admitted for induction of labor

Exclusion Criteria:

- Parturients admitted in labor