Pleural manometry in pleural effusion

Abstract

Pleural manometry is a valuable tool to determine lung expansibility and helps to avoid unsafe pressure changes during thoracentesis. Study design: Cross-sectional descriptive study. Aim of the work: To measure the pleural pressure during thoracocentesis in patients with pleural effusion and the value of their measurement in both diagnostic and therapeutic decisions. Patients and methods: Forty-four patients with pleural effusion were included. Thoracocentesis was performed for all patients. End-expiratory pleural pressure values were recorded after the withdrawal of 5 ml of fluid (initial pleural pressure), after the removal of every 500 ml for the first liter then after the withdrawal of every 250 ml for the second liter, and every 100 ml thereafter until the procedure completed. The last recorded pressure was used as the closing pressure. Comparisons were done according to the etiology and character of the effusion (transudate or exudate). The pressure/volume curves were done and studied. Results: Twenty out of 34 patients with exudative pleural effusion having a pleural space elastance >14.5 cm H2O/L were identified. These patients had a diagnosis of malignant effusion either primary or secondary (14/20 patients), or inflammatory causes (6/20 patients). All the 10 patients with transudative effusion had an elastance <14.5 cm H2O/L. The study revealed a statistically significant decrease in closing pressure in the symptomatic group when compared to non-symptomatic group (p value = 0.022), none of our patients (including symptomatic patients) had exceeded the proposed cutoff value for unsafe pleural pressures (−20 cm H2O). Conclusion: Pleural manometry is proved a useful tool to differentiate freely expandable lungs from lungs with entrapment. It is proved as a useful guide as to when to terminate thoracentesis in large volume thoracentesis.

Keywords

• Pleural manometry
• Thoracentesis
• Pleural elastance
• Symptoms
• Lung entrapment