Comparing volumetric and biochemical assessment of intravasation caused by hysteroscopic surgery

During hysteroscopic surgery intravasation of irrigation fluid occurs, leading to potentially dangerous intravascular fluid overload. Currently, intravasation is usually measured volumetrically as fluid deficit. Intravasation could also be calculated using the decrease in hemoglobin or increase in chloride ion concentration, both phenomena known to result from intravasation. We compared the values of intravasation measured volumetrically as fluid deficit versus calculated from the biochemical change in hemoglobin and chloride. We expected that these values would show strong correlation and agreement.

In a retrospective data analysis of 51 patients who underwent hysteroscopic resection of myomas or endometrium a pre and post procedure concentration of haemoglobin and chloride was available. The fluid deficit was plotted against the two versions of calculated intravasation. Furthermore, we put the data into Bland-Altman plots to scrutinize their relationship.

The volumetric assessed fluid deficit and both versions of biochemically assessed intravasation, either using the change in hemoglobin or chloride ion concentration, turned out to be three totally different entities with weak correlation. Bland-Altman plots show too wide limits of agreement, and a striking difference between the two methods of calculated intravasation.

Our study shows significant differences and poor agreement between volumetric and biochemically assessed intravasation. Based on this study, routinely assessing intravasation by biochemical methods does not have additional benefit compared to the volumetric fluid deficit. It remains unclear which method resembles true intravasation.