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

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

Non-invasive Versus Invasive Blood Pressure Measurement in the Morbidly Obese Parturient (BMI >= 40 kg/m2) With Severe Preeclampsia: A Comparison of Direct Arterial Blood Pressure Measurements With Readings Obtained Using Either Large Cylindrical or Novel Conical Bariatric Upper Arm Blood Pressure Cuffs

The study will compare agreement of invasive blood pressure measurements with non-invasive blood pressure measurements measured with a conical blood pressure and large standard upper arm rectangular cuff in morbidly obese severely hypertensive (systolic blood pressure > 160 mmHg) parturients.

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.

BP recording with noninvasive conical Ultracheck Curve BP cuff and direct invasive arterial pressure monitoring; then with traditional cylindrical BP cuff and direct invasive arterial pressure monitoring

BP recording with noninvasive traditional cylindrical BP cuff and direct invasive arterial pressure monitoring; then with conical Ultracheck Curve BP cuff and direct invasive arterial pressure monitoring

Direct invasive arterial pressure readings will be recorded simultaneously with non-invasive measurements

Absolute difference between the mean of 2 non-invasive systolic blood pressure readings and mean of 2 invasive systolic blood pressure readings

Comparison of Mean Arterial Pressure (MAP) Measured Withnon-invasive Cuffs to MAP Measured by Invasive Blood Pressure Monitoring

Absolute difference between the mean of 2 non-invasive diastolic blood pressure readings and mean of 2 invasive diastolic blood pressure readings

Mean of 2 Diastolic Blood Pressure Non-invasive BP Measurements Taken With Cylindrical and Conical BP Cuffs

Mean of 2 diastolic blood pressure non-invasive BP measurements taken with cylindrical and conical 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

Ashworth DC, Maule SP, Stewart F, Nathan HL, Shennan AH, Chappell LC. Setting and techniques for monitoring blood pressure during pregnancy. Cochrane Database Syst Rev. 2020 Jul 23;8(8):CD012739. doi: 10.1002/14651858.CD012739.pub2.