Clinical Utility of Red Cell Distribution Width in Patients with Pleural Effusion

BACKGROUND

The red cell distribution width (RDW) value has been recently recognized as a valuable biomarker in clinical practice. The RDW value has not been evaluated so far in patients with pleural effusion. Thus, this study aimed to investigate whether RDW could distinguish between exudative and transudative pleural effusions.

MATERIALS AND METHODS

We measured protein and lactate dehydrogenase levels on both pleural fluids and serum samples from 223 cases and classified them as transudates or exudates based on the classic Light's criteria. We collected blood cell count elements such as RDW from the medical records. We also investigated the correlation between RDW and the nature of pleural effusion.

RESULTS

In 55.2% of the patients, pleural fluid was exudative. Although we found no significant association between RDW and the nature of the pleural fluid, we detected a significantly higher amount of RDW (14.9 ≤) in patients with exudative pleural effusion compared to transudate (66.7% vs. 33.3%; P= 0.01). In this category, neoplastic conditions were mostly observed in the patients (76.3%), followed by pulmonary thromboembolism (21.1%) and systemic lupus erythematous (2.6%).

CONCLUSION

The findings could not reveal any noticeable correlation between RDW and the Light criteria. However, it appears that elevated RDW levels give insights into the valuable nature of RDW in different conditions such as neoplastic diseases.

Pleural Space Elastance and Its Relation to Success Rates of Pleurodesis in Malignant Pleural Effusion

Background

Pleurodesis fails in 10%–40% of patients with recurrent malignant pleural effusions malignant pleural effusion and dyspnea. This study aimed to assess the values of pleural elastance (P_EL) after the aspiration of 500 mL of pleural fluid and their relation to the pleurodesis outcome, and to compare the pleurodesis outcome with the chemical characteristics of pleural fluid.

Methods

A prospective study was conducted in Kasr El-Aini Hospital, Cairo University, during the period from March 2019 to January 2020. The study population consisted of 40 patients with malignant pleural effusion. The measurement of P_EL after the aspiration of 500 mL of fluid was done with “P_EL 0.5” (cm H₂O/L), and the characteristics of the pleural fluid were chemically and cytologically analyzed. Pleurodesis was done and the patients were evaluated one month later. The P_EL values were compared with pleurodesis outcomes.

Results

After 4-week of follow-up, the success rate of pleurodesis was 65%. The P_EL 0.5 was significantly higher in failed pleurodesis than it was in successful pleurodesis. A cutoff point of P_EL 0.5 >14.5 cm H₂O/L was associated with pleurodesis failure with a sensitivity and specificity of 93% and 100%, respectively. The patients with failed pleurodesis had significantly lower pH levels in fluid than those in the successful group (p<0.001).

Conclusion

P_EL measurement was a significant predictor in differentiating between failed and successful pleurodesis. The increase in acidity of the malignant pleural fluid can be used as a predictor for pleurodesis failure in patients with malignant pleural effusion.