Pannus Retraction for Ultrasound Evaluation of the Obese Gravida: A Pilot Study

Pregnancies complicated by obesity have an increased risk of multiple pregnancy complications, including structural fetal anomalies. Therefore, maternal obesity (BMI ≥30 kg/m2) is an indication for a detailed anatomic ultrasound examination. Ultrasound is a critical tool for the detection of congenital anomalies; however, obesity makes ultrasound examinations technically challenging. The primary objective of this ambidirectional cohort pilot study is to evaluate whether utilization of a pannus retractor is associated with increased rates of detailed anatomic ultrasound completion amongst pregnant patients with a body mass index (BMI) greater than or equal to 40 kg/m2. Retrospective data will be collected for 100 patients with a BMI of 40 kg/m2 or greater to assess the baseline rate of completion of 16 components of the detailed anatomic survey prior to the intervention. We plan to enroll 20 patients into a prospective pilot to the intervention arm. The intervention is placement of an adhesive medical device, the traxi® Panniculus Retractor (Laborie, Portsmouth, New Hampshire), which was developed for pannus retraction during cesarean section. Adequacy of anatomic ultrasound completion will be based upon 16 pre-defined views from the anatomic survey. Ultrasound completion rates from the prospective cohort of participants that undergo ultrasound evaluation using a pannus retractor will be compared to a historical cohort without pannus retractor use. We hypothesize that use of a pannus retractor for pregnant participants with BMI greater than or equal to 40 kg/m2 increases the rate of anatomical ultrasound completion.

Aim 1: Determine the completion rate of detailed obstetric ultrasound when using the pannus retractor device adhesive for participants with BMI of 40 kg/m2 or greater. Retrospective data will be collected for 100 patients with a BMI of 40 kg/m2 or greater to assess the baseline rate of completion of 16 components of the detailed anatomic survey. We will prospectively enroll twenty participants with BMI of at least 40 kg/m2 who consent to having a pannus retractor device adhesive placed for their anatomic ultrasound exam. Inclusion and exclusion criteria will be followed as detailed elsewhere. Participant measurements including current height, weight, and pannus grade will be recorded. The pannus retractor device adhesive will be placed by research personnel and sonographers who have been trained in proper application of the device, per manufacturer's instructions. The start time of adhesive application will be recorded. The ultrasound exam will then proceed as a routine ultrasound exam, except for two additional ultrasound measurements. Using no pressure, the distance from ultrasound probe to the amniotic cavity will be measured with and without the pannus retractor in place. Other collection variables will be available from chart review, namely age, race, ethnicity, insurance status, estimated due date, pre-pregnancy BMI, BMI at first obstetric visit, diabetic status, smoking status, parity, prior abdominal surgical status, date of ultrasound, fetal presentation, placental location, sonographer, reading physician, time of first and last ultrasound image acquisition, and whether transvaginal imaging was used. The outcome measure of interest, completion of adequate visualization of sixteen views, will be available from review of the final ultrasound report. The rate of completed studies from the prospective population will be compared to historical data to determine if Aim 1 hypothesis is true. Aim 2: Determine changes to the sonographer experience for the 20 patients enrolled in the prospective cohort portion of this project. A survey will be administered to the sonographers who perform the ultrasounds with the pannus retractor adhesive in use. The amount of discomfort experienced in their arm or shoulder while scanning, their confidence in the quality of their images, and whether the ultrasound was made easier by use of the adhesive will be assessed by a Likert scale with space for free text comments. Aim 3: Evaluate the participant experience for the 20 patients enrolled in the prospective cohort portion of this project. The comfort, satisfaction and enjoyment of the ultrasound experience will be assessed by a Likert scale.

All prospective participants will receive the intervention for one occurrence. Retrospective participants' results will be observed without any intervention.

All prospective participants will be consented to use of the intervention, a pannus retractor at time of detailed obstetric ultrasound.

This is an adhesive medical device designed to retract a pannus during cesarean section. It will be applied to prospective participants according to manufacturer instructions, just prior to the detailed anatomic ultrasound.

The ultrasound report will be evaluated to determine if the following elements were adequately visualized: lateral ventricles, cerebellum, cavum septum pellucidum, face, four chamber view, right outflow tract, left outflow tract, three vessel view, three vessel trachea view, spine, ventral wall, umbilical cord, stomach, left kidney, right kidney, bladder. If any one or more of these elements are not adequately visualized, the study will be interpreted as "incomplete." The proportion of complete to incomplete studies will be compared between the retrospective and prospective cohorts.

Inclusion Criteria: Pregnant patients presenting for detailed anatomic ultrasound with a BMI of at least 40 kg/m2 English or Spanish speaking BMI of at least 40.0 kg/m2 at first obstetric visit during this pregnancy Gestational age between 18 weeks 0 days to 23 weeks 6 days Exclusion Criteria: Patients who have already had an anatomy ultrasound during the same pregnancy with our department History of tape/adhesive allergy Multifetal gestation Known intrauterine fetal demise

All study investigators will have access to the database management system that includes IPD. Only de-identified results will be distributed after analysis.

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