Determination of Whole Blood Loss from Minimally Invasive Myomectomy Using a Standardized Formula: A Pilot Study.

STUDY OBJECTIVE: To determine the median perioperative blood loss (PBL) during minimally invasive surgical (MIS) myomectomy.

DESIGN: Prospective pilot study.

SETTING: Large academic teaching hospital.

PATIENTS: 31 patients underwent laparoscopic or robotic myomectomy and completed a postoperative complete blood count (CBC) from November 2020 to August 2022. Patients had to have at least one fibroid greater than or equal to 3 cm on preoperative imaging.

INTERVENTIONS: A CBC was collected preoperatively within 7 days of surgery. Estimated blood loss (EBL) was determined by the surgeon intraoperatively. A repeat CBC was drawn between postoperative days 2 through 4. PBL was calculated using the equation PBL= (patient weight in kg x 65 cc/kg) x (preoperative hematocrit - postoperative hematocrit)/preoperative hematocrit.

MEASUREMENTS AND MAIN RESULTS: Median PBL (536.3 cc (270.0, 909.3)) was greater than median EBL (200.0 cc (75.0, 500.0)). PBL ranged from a net gain of 191.5 cc to net loss of 2362.5 cc. Median size of the largest fibroid on preoperative imaging was 8.8 cm (6.6, 11.5), and median weight of fibroids removed was 321 gm (115, 519). 51.6% of patients had one fibroid removed, and 48.4% had two or more fibroids removed. Five patients were converted to laparotomy, four from robotic approaches. Two patients required a blood transfusion.

CONCLUSIONS: Calculated PBL was greater than intraoperative EBL. This suggests there is continued blood loss post myometrial bed closure. Blood loss should be evaluated both during and after myomectomy, as intraoperative EBL underestimates total PBL.