What happens to the pleural space affected by malignant effusion after bedside pleurodesis?

Evaluate radiological characteristics of postpleurodesis pleural space of patients with recurrent malignant pleural effusion(RMPE).

Prospective cohort study including patients with RPME treated with bedside pleurodesis. We used CT scans to calculate pleural cavity volume immediately before pleurodesis(iCT) and 30 days after(CT30). Radiological evolution was calculated by the difference between pleural volumes on CT30 and iCT(Δvolume). We categorized initial pleural volume as small(<500 mL) or large space(≥500 mL) and Δvolume as positive(>254.49 mL), unchanged(≥-268.77-≤ 254.49 mL), or negative(<-268.77 mL). Futhermore, we analyzed clinical effectiveness, pleural elastance, and adverse events.

A total of 87 patients were analyzed. Pleural volume varied from 35-2750 mL in iCT and from 0-2995 mL in CT30(P = 0.753). A total of 54 patients had initial small pleural space(62.06%) and 33 large(37.93%). Clinical failure occurred in 7.4% of small space group and in 24.6% of large(P = 0.051, OR4.0(CI:1.098-14.570)). In small space group, 27.77% evolved with positive, 66.66% with unchanged and 5.55% with negative Δvolume. In the large space group these numbers were respectively 21.21%, 27.27%, and 51.51%.

There is significant variability on pleural space volume. However, pleural volume remains unchanged in many cases. Besides that, more than half patients with initial large space coursed with relevant reduction. Finally, patients with initial small space presented a greater chance of clinical success.