Effects of pleural drainage on oxygenation in critically ill patients

Pleural effusion is common among critically ill patients and associated with clinical consequences; however, the benefits of draining pleural effusion remain debatable. Thus, we aimed to investigate pleural drainage effectiveness by focusing on preprocedure patient status.

We retrospectively analyzed 22 patients with pleural effusion. Gas exchange, ventilator settings, vital signs, inflammatory response, and nutrition status were examined preprocedure and 24 h and 1 week postprocedure. Data were analyzed using the non-parametric test and discriminant analysis with receiver operating characteristic curves.

The partial arterial oxygen pressure (PaO₂) to fraction of inspiratory oxygen (F_IO₂) (P/F) ratio at 24 h was higher postdrainage than predrainage (250 ± 87 versus 196 ± 84, P < 0.05); however, no significant difference between the P/F ratio predrainage and 1 week postdrainage was noted. Patients were classified into effective and ineffective groups according to a 110% increase in the P/F ratio 1 week postdrainage compared with predrainage. The predrainage P/F ratio was lower in the effective group than in the ineffective group (165 ± 91 versus 217 ± 74, P < 0.05). Discriminant analysis showed the area under the receiver operating characteristic curve was 0.72; the cut-off value of the predrainage P/F ratio (divided into effective and ineffective groups) was 174.

Pleural drainage could be effective in patients who have lower preprocedure P/F ratios.