Conical Forearm and Cylindrical Upper Arm Non-Invasive Blood Pressure (NIBP) Measurements in Pregnant Patients

NCT ID: NCT06466161

Last Updated: 2025-05-06

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 110 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-04-29
• Study Completion Date: 2027-09-01

Brief Summary

The diagnosis of hypertensive disease during pregnancy is predicated on strict blood pressure thresholds: 140/90 on at least two occasions measured four hours apart for both gestational hypertension and preeclampsia. An improvement in diagnostic accuracy of even 5mm Hg would be significant, as reflected by the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring, and the International Organization for Standardization (ISO)consensus for validation of non-invasive blood pressure (NIBP) devices during pregnancy. Given the known inaccuracies of upper arm cylindrical cuff measurements in morbidly obese patients, a conical cuff which provides more accurate measurements will translate into direct patient benefit via more informed diagnosis and management. Fewer women may be exposed to unnecessary treatment, preterm delivery, and/or cesarean section. Recognizing the increasing prevalence of morbid obesity and hypertensive disease amongst pregnant women in the United States, the identification of a more accurate non-invasive cuff is desperately needed. Increasing the accuracy of NIBP measurements on Labor and Delivery has the potential to directly impact the management of tens of thousands of morbidly obese pregnant women diagnosed with hypertensive disease in the United States every year. Establishing the level of agreement between conical forearm and cylindrical upper arm cuffs will shed light on the presence and magnitude of any disparity between measurement methods.

STUDY ENDPOINTS:

Primary Outcome Measures:

• Agreement between conical and cylindrical cuff systolic blood pressure across groups
• Agreement between conical and cylindrical cuff diastolic blood pressure across groups

Secondary Outcome Measures:

• Agreement between conical and cylindrical cuff mean arterial pressure

Detailed Description

After participants have provided written informed consent they will be enrolled into one of four groups: (1) normotensive/non-obese (2) normotensive/obese (3) hypertensive/non-obese and (4) hypertensive/obese. The threshold for hypertension will be a BP measurement greater than 140/90 mmHg on two occasions at least 4 hours apart. After informed consent has been obtained, body weight (kg) and height (cm) will be measured on calibrated scales and BMI calculated. Arm circumference will be measured proximally just beneath the axilla, at mid- point between the acromion and the olecranon, and distally just above the antecubital fossa in centimeters. Forearm circumference will be measured, in millimeters, proximally just beneath the olecranon, at mid-point between the olecranon and the styloid apophysis, and distally just above the styloid apophysis. Upper arm length will be measured from the acromion to the olecranon in centimeters. Forearm length will be measured from the olecranon to the styloid apophysis in centimeters. Upper arm cuffs will be placed at the mid-point between the acromion and the olecranon processes. All BP measurements will be obtained from the participants while in the sitting position, and the arm contralateral to the peripheral intravenous catheter (PIV) will be chosen for measurement. If the PIV has not yet been placed, the arm selection will be made by the patient. Baseline BP measurement will be performed at the upper arm after at least a 5-minute resting period utilizing a large-sized cylindrical cuff. Baseline BP measurement at the forearm will be performed using a conical forearm cuff previously validated in non-pregnant patients with arm circumferences greater than or equal to 40 cm23 (RADIAL-CUF, GE HealthCare, Milwaukee, Wisconsin). The forearm cuff will be placed 3 cm from the styloid process of the ulna palpable at the wrist.

After two minutes have elapsed since the baseline measurements, sequential, paired BP measurements will then be obtained by cycling either the upper arm cylindrical cuff or forearm conical cuff, waiting 60 seconds after the measurement, then cycling the other cuff. The choice of cuff to be cycled first (conical or cylindrical) will be block randomized. Additional sequential measurements will then be obtained 2, 4, 6, 8, and 10 minutes after the first set. After the initial measurements, the upper arm cuff will automatically cycle every 15 minutes. Thus, all patients will have six sets of sequential BP measurements. Any decision to initiate antihypertensive therapy will be made by the patient's obstetrical provider, using an institutional algorithm and with reference to cylindrical cuff pressures.

Conditions

Hypertension in Pregnancy; Hypertension; Obesity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Group 1 Upper arm cylindrical cuff

In Group 1 the upper arm cylindrical cuff is inflated first and the blood pressure is measured.

After one minute has elapsed, the forearm conical cuff is inflated and blood pressure measured.

Group Type: ACTIVE_COMPARATOR

Upper Arm Cylindrical Blood Pressure Cuff

Intervention Type: DEVICE

In Group 1, the upper arm cylindrical cuff is inflated first, followed by inflation of the forearm conical cuff.

Group 2 Forearm conical cuff

In Group 2 the forearm conical cuff is inflated first and the blood pressure is measured. After one minute has elapsed, the upper arm cylindrical cuff is inflated and blood pressure measured.

Group Type: EXPERIMENTAL

Forearm Conical Blood Pressure Cuff

Intervention Type: DEVICE

In Group 2, the forearm conical cuff is inflated first, followed by inflation of the upper arm cylindrical cuff.

Interventions

Upper Arm Cylindrical Blood Pressure Cuff

In Group 1, the upper arm cylindrical cuff is inflated first, followed by inflation of the forearm conical cuff.

Intervention Type: DEVICE

Forearm Conical Blood Pressure Cuff

In Group 2, the forearm conical cuff is inflated first, followed by inflation of the upper arm cylindrical cuff.

Intervention Type: DEVICE

Other Intervention Names

Upper Arm Cylindrical Blood Pressure Cuff Inflated First; Forearm Conical Blood Pressure Cuff Inflated First

Eligibility Criteria

Inclusion Criteria

• Women who are 18 years of age or older with a
• Body mass index (BMI) of 20 kg/m2 or greater
• Present to Labor and Delivery with or without a diagnosis of gestational hypertension, preeclampsia, or chronic hypertension with super-imposed preeclampsia, in spontaneous labor or for induction of labor

Exclusion Criteria

• Significant peripheral arterial disease resulting in at least a 10 mm Hg blood pressure difference between both arms
• History of repaired or unrepaired congenital heart disease
• History of significant arrythmia
• History of pacemaker or implantable cardioverter defibrillator placement
• History of sickle cell disease
• History of Raynaud's phenomenon on any extremity
• History of lymph node dissection of either upper extremity
• Patients who are less than 18 years of age

• Minimum Eligible Age: 18 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: No

Sponsors

Northwestern University

OTHER

Sponsor Role: lead

Responsible Party

Adithya Bhat

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Adithya Bhat, MD

Role: PRINCIPAL_INVESTIGATOR

Northwestern University

Locations

Prentice Women's Hospital

Chicago, Illinois, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Adithya Bhat, MD

Role: CONTACT

adithya.bhat@northwestern.edu

312-472-3585

Paul Fitzgerald, RN,BSN,MS

Role: CONTACT

p-fitzgerald2@northwestern.edu

312-695-1064

Facility Contacts

Paul Fitzgerald, RN,BSN,MS

Role: primary

p-fitzgerald2@northwestern.edu

312-926-1064

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Other Identifiers

STU00221793

Identifier Type: -

Identifier Source: org_study_id