Effects of pleural drainage on oxygenation in critically ill patients.

Aim: 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.
Methods: 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.
Results: The partial arterial oxygen pressure (PaO ₂ ) to fraction of inspiratory oxygen (F _I O ₂ ) (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.
Conclusions: Pleural drainage could be effective in patients who have lower preprocedure P/F ratios.
Competing Interests: Approval of the research protocol: This study was approved by the Institutional Review Board of Tokyo Medical University (IRB no. 2389). Informed consent: All participants provided informed consent. Registry and the registration no. of the study/trial: N/A. Animal studies: N/A. Conflict of interest: None.
(© 2020 The Authors. Acute Medicine & Surgery published by John Wiley & Sons Australia, Ltd on behalf of Japanese.)