Abdominal Ultrasound Assessment in the Post-cesarean Patient

Hemorrhage is the second leading cause of maternal mortality in the United States. Women have an increased risk of hemorrhage after cesarean sections.Uterine atony is the culprit in 80% of cases, but in the post-operative patient, an intra-abdominal bleed requiring a return to the operating room must also be considered. The Focused Assessment with Sonography in Trauma (FAST) has been used in the emergency department to evaluate for intra-abdominal bleeding after trauma. FAST evaluation has not been studied in the post-operative period for evaluation for intra-abdominal bleeding. Ultrasound is a rapid and readily-available modality for this type of evaluation, and obstetricians are already familiar with the technology. But one must be cautious, as a certain amount of free fluid on CT is common in the postoperative patient. Before basing clinical decisions on a FAST scan, we much determine how much fluid is normal in a patient after cesarean delivery. We hypothesize that a certain amount of fluid in the abdomen visualized by ultrasound may be normal after a cesarean delivery, and that for ultrasound to become a valuable modality to assess for intra-abdominal bleeding in the post-cesarean patient, the amount of normal fluid must be determined. However, in order to interpret what an "appropriate" amount of fluid would be, we will also need an assessment of patient hemoglobin levels. Thus, we would additionally plan to validate a rapid, non-invasive hemoglobin measurement for use in the post-cesarean obstetric patient. The Pronto7 device measures the blood's absorption of multiple wavelengths of light to determine hemoglobin. The device avoids a blood draw and its associated pain. It also provides immediate results. We anticipate that we will identify an association between the amount of fluid seen on ultrasonographic evaluation after cesarean delivery and adverse outcomes such as larger than expected decrease in hemoglobin, need for transfusion and need for take-back to the operating room. We also anticipate that the use of non-invasive hemoglobin measurements may provide a rapid, painless assessment of postoperative hemoglobin; this may allow us to identify patients who merit earlier postoperative monitoring with a traditional CBC. It may also allow us to identify women who do not need an invasive CBC on postoperative day 1, which may decrease blood draws and costs in the future.

Inclusion criteria

• Pregnant
• 18 years of age or older
• English-speaking
• Non-urgent cesarean sections

Exclusion criteria

• Preeclampsia/eclampsia
• <18 years old
• Urgent/emergent cesarean section
• Not English-speaking
• Unable to consent