Effect of large-volume intrapleural saline lavage for empyema: a single-center, prospective cohort study

Intrapleural fibrinolytic therapy has emerged as a preferred treatment for empyema, helping to reduce the need for surgery and shorten hospital stays. However, fibrinolytic drugs may not be available in some regions due to distribution challenges. In such situations, intrapleural saline lavage can serve as an effective alternative treatment option. Evidence supporting the use of intrapleural saline lavage remains limited, primarily because previous studies have used low lavage volumes.

We aimed to compare hospital stays, 30-day mortality rates, rates of referral to surgery, length of drainage, and adverse events between two groups of empyema patients: one receiving pleural lavage with urokinase administration; and the other receiving pleural lavage using 500 mL of saline. This was a single-center, prospective cohort study that analyzed patients contracting empyema with positive culture of pleural fluids admitted to our hospital between March 2021 and March 2023.

The 33 patients comprised 18 in the urokinase group and 15 in the saline group. No significant differences were seen in 30-day mortality rate (p = 0.08) or referral for surgery (p = 0.618). Although the overall duration of hospital stay appeared comparable between the groups, competing risk analysis accounting for death as a competing event demonstrated a significant difference in time to discharge (p = 0.023), with a longer hospital stay observed in the saline group. Non-inferiority analysis showed significant differences between groups in additional drainage tubes.

No significant difference in surgical referrals or mortality was evident between intrapleural saline lavage and urokinase therapy. However, saline lavage in acute empyema may be less effective and result in longer hospital stays, even with larger volumes.

This study was performed using data from a prospective epidemiological study for patients with pneumonia (UMIN000004353).