A pseudo-Rumsfeldian approach to pleural effusions in mechanically ventilated patients

Pleural effusion and thoracentesis in ICU patients: A longitudinal observational cross-sectional study

BACKGROUND

Pleural effusion is common among patients in the intensive care unit (ICU) but reported prevalence varies. Thoracentesis may improve respiratory status, however, indications for this are unclear. We aimed to explore prevalence, development, and progression of pleural effusion, and the incidence and effects of thoracentesis in adult ICU patients.

METHODS

This is a prospective observational study utilizing repeated daily ultrasonographic assessments of pleurae bilaterally, conducted in all adult patients admitted to the four ICUs of a Danish university hospital throughout a 14-day period. The primary outcome was the proportion of patients with ultrasonographically significant pleural effusion (separation between parietal and visceral pleurae >20 mm) in either pleural cavity on any ICU day. Secondary outcomes included the proportion of patients with ultrasonographically significant pleural effusion receiving thoracentesis in ICU, and the progression of pleural effusion without drainage, among others. The protocol was published before study initiation.

RESULTS

In total, 81 patients were included of which 25 (31%) had or developed ultrasonographically significant pleural effusion. Thoracentesis was performed in 10 of these 25 patients (40%). Patients with ultrasonographically significant pleural effusion, which was not drained, had an overall decrease in estimated pleural effusion volume on subsequent days.

CONCLUSION

Pleural effusion was common in the ICU, but less than half of all patients with ultrasonographically significant pleural effusion underwent thoracentesis. Progression of pleural effusion without thoracentesis showed reduced volumes on subsequent days.

Clinically Significant Pleural Effusion in Intensive Care: A Prospective Multicenter Cohort Study

OBJECTIVES

The prevalence and optimal management of clinically significant pleural effusion, confirmed by thoracic ultrasound, in the critically ill is unknown. This study aimed to determine: 1) the prevalence, characteristics, and outcomes of patients treated in intensive care with clinically significant effusion and 2) the comparative efficacy and safety of pleural drainage or expectant medical management.

DESIGN

A prospective multicenter cohort study.

SETTING

ICUs in four teaching hospitals in Western Australia.

PATIENTS

Consecutive patients with clinically significant pleural effusions (depth ≥ 2 cm on thoracic ultrasound with clinician-determined adverse effects on patient progress).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was the change in Pao2:Fio2 (mm Hg) ratio from baseline to 24 hours. Changes in diagnosis and treatment based on pleural fluid analysis and pleural effusion related serious adverse events between those who underwent either drainage within 24 hours or expectant management were compared. Of the 7,342 patients screened, 226 patients (3.1%) with 300 pleural effusions were enrolled. Early drainage of pleural effusion occurred in 76 patients (34%) and significantly improved oxygenation (Pao2:Fio2 ratio 203 at baseline vs 263 at 24 hr, +29.6% increment; p < 0.01). This was not observed in the other 150 patients who had expectant management (Pao2:Fio2 ratio 250 at baseline vs 268 at 24 hr, +7.2% increment; p = 0.44). The improvement in oxygenation after early drainage remained unchanged after adjustment for a propensity score on the decision to initiate early drainage. Pleural effusion related serious adverse events were not different between the two groups (early drainage 10.5% vs no early drainage 16.0%; p = 0.32). Improvements in diagnosis were noted in 91 initial (nonrepetitive) drainages (76.5% out of 119); treatment strategy was optimized after 80 drainage episodes (59.7% out of 134).

CONCLUSIONS

Early drainage of clinically significant pleural effusion was associated with improved oxygenation and diagnostic accuracy without increased complications.