Ascites Index - a novel technique to evaluate ascites in ovarian hyperstimulation syndrome: a concept-proof study

Controlled ovarian hyperstimulation is an important step in infertility treatment. In some cases, however, ovar-ian hyperstimulation syndrome (OHSS) can occur. In its severe forms, ascites is likely to develop, associated with dyspnea. The aim of this study was to explore the usefulness of Ascites Index (AsI), a new tool for quantitative determination of ascites in patients with OHSS, to obtain data for planning further trials.

Twelve patients with OHSS and ascites were included in the study. All patients were admitted to the hospital because of abdominal pain and dyspnea due to increasing ascites. Ultrasound measurements of ascites extent were performed in four external quadrants of the abdomen. Pockets of free fluid were measured. The obtained values were totaled, forming the Ascites Index (AsI), similarly to the amniotic fluid index. Because of dyspnea, paracentesis was performed in all cases.

Median AsI at which patients reported dyspnea was 29.0 cm (range 21.6-38.6 cm). At AsI values less than 21.6 cm, no dyspnea was observed in any of the 12 studied patients. To avoid complications, 2000 mL of ascitic fluid was collected in each patient. After paracentesis, range of AsI decreased to 12.1-14.5 cm.

The proposed AsI seems to be a promising tool for estimating and monitoring the ascites extent in OHSS. It can be estimated using basic ultrasound equipment. AsI requires further studies for standardization and transferability to other causes of ascites.