Background: Prone position (PP) and the positive end-expiratory pressure (PEEP)-induced lung recruitment maneuver (LRM) are both efficient in improving oxygenation and prognosis in patients with ARDS. The synergistic effect of PP combined with PEEP-induced LRM in patients with ARDS remains unclear. We aim to explore the effects of PP combined with PEEP-induced LRM on prognosis in patients with moderate to severe ARDS and the predicting role of lung recruitablity. Methods: Patients with moderate to severe ARDS were consecutively enrolled. The patients were prospectively assigned to either the intervention (PP with PEEP-induced LRM) or control groups (PP). The clinical outcomes, respiratory mechanics, and electric impedance tomography (EIT) monitoring results for the two groups were compared. Lung recruitablity (recruitment-to-inflation ratio: R/I) was measured during the PEEP-induced LRM procedure and was used for predicting the response to LRM. Results: Fifty-eight patients were included in the final analysis, among which 28 patients (48.2%) received PEEP-induced LRM combined with PP. PEEP-induced LRM enhanced the effect of PP by a significant improvement in oxygenation (∆PaO₂/FiO₂ 75.8 mmHg vs. 4.75 mmHg, p < 0.001) and the compliance of respiratory system (∆C_rs, 2 mL/cmH₂O vs. −1 mL/cmH₂O, p = 0.02) among ARDS patients. Based on the EIT measurement, PP combined with PEEP-induced LRM increased the ventilation distribution mainly in the dorsal region (5.0% vs. 2.0%, p = 0.015). The R/I ratio was measured in 28 subjects. The higher R/I ratio was related to greater oxygenation improvement after LRM (Pearson’s r = 0.4; p = 0.034). Conclusions: In patients with moderate to severe ARDS, PEEP-induced LRM combined with PP can improve oxygenation and dorsal ventilation distribution. R/I can be useful to predict responses to LRM.

Background: Allostatic load reflects the cumulative physiological effects of chronic and repeated stress on the body and is associated with dysregulation of multiple systems. This study aimed to examine the association between the allostatic load score (ALS) and the development of delirium in intensive care unit (ICU) patients. Method: The adult patients from the Medical Information Mart for Intensive Care (MIMIC-IV) database were screened and included in this study. Allostatic load was scored by hemoglobin A1c, high-density lipoprotein, total cholesterol, systolic blood pressure, diastolic blood pressure, body mass index, C-reactive protein, and serum albumin, and varied from 0 to 8. Restricted cubic spline and multivariate logistic regression were used to assess the relationship between ALS and delirium risk in the ICU. The threshold of the ALS was determined by the decision tree approach. A sensitivity analysis was also conducted. Results: A total of 656 patients were included in the study, and the incidence of delirium was 50.6% (n = 332). In a fully adjusted restricted cubic spline model, an increase in ALS was linearly positively correlated with the occurrence of delirium in the ICU (p-overall = 0.039, p-nonlinear = 0.506). The threshold for ALS was determined to be 3. ALS ≥ 3 was associated with increased delirium rates (p < 0.001), longer hospital stays (p < 0.001), and higher in-hospital mortality (p = 0.002). Subgroup analyses revealed no significant interactions (all p values for interactions > 0.05). Conclusions: Higher ALS was linearly associated with increased risk of ICU delirium. An ALS ≥ 3 identified patients with greater delirium incidence, longer hospital stays, and higher mortality.

Background: Early reports highlighted unique features of COVID-19-associated ARDS. The combination of prone position (PP) and positive end-expiratory pressure (PEEP)-induced lung recruitment maneuver (LRM) has demonstrated efficacy in enhancing oxygenation and improving outcomes in patients with ARDS, but it remains unknown whether there is a difference between COVID-19 ARDS and non-COVID-19 ARDS. Method: This study is a secondary analysis of a previously conducted randomized controlled trial. Patients with moderate to severe ARDS were consecutively enrolled during the study period (June–December 2023). After initiation of PP, patients received a PEEP-induced LRM followed by 12 h of daily PP. The interventions were repeated at least three times over the subsequent 3 days. Clinical outcomes, respiratory mechanics, and electrical impedance tomography (EIT) results were evaluated. Results: Twenty-eight patients were included in the final analysis, half of whom were infected with COVID-19 (50%). The PEEP-induced LRM led to greater improvement in oxygenation among COVID-19 ARDS than non-COVID-19 ARDS (∆PaO₂/FiO₂ ratio 90.5 mmHg vs. 65.5 mmHg, p < 0.05). Based on EIT measurement, compared with the non-COVID-19 ARDS group, PEEP-induced LRM resulted in a greater increase in ventilation distribution, mainly in the dorsal regions of interest 4 (ROI 4) ventilation distribution (∆ROI4 4.5% vs. 1.0%, p = 0.01) and in dorsal regional ventilation (∆dorsal regional ventilation 10.0% vs. 5.5%, p = 0.04) in the COVID-19 ARDS group. Conclusions: Compared to typical ARDS, PEEP-induced LRM combined with PP may be more effective in enhancing oxygenation in COVID-19-related ARDS.

Rationale: Prone position (PP) and PEEP-induced lung recruitment maneuver(LRM) are both efficacy in improving oxygenation and prognosis in patients with ARDS. The synergistic effect of PP combined with PEEP-induced LRM in patients with ARDS remains unclear. Objectives: To explore the effects of PP combined with PEEP-induced LRM on prognosis in patients with moderate to severe ARDS and the predicting role of lung recruitablity. Method: Patients with moderate to severe ARDS were consecutively enrolled. The patients were prospectively assigned to either the intervention(PP with PEEP-induced LRM)or control group (PP group) (Fig. 1). The clinical outcome, respiratory mechanics and EIT monitoring results in the two groups were compared. Lung recruitablity (recruitment to inflation ratio,R/I)was measured during PEEP-induced LRM procedure and was used for predicting the response to LRM. Results: Fifty-eight patients are included in the final analysis, among which 28 patients(48.2%) received PEEP-induced LRM combined with PP.PEEP-induced LRM can enhance the effect of PP by significant improving in oxygenation (PaO₂/FiO₂ 75.8vs4.75,P<0.001) and compliance of respiratory system (2 vs -1,P=0.02) among ARDS patients (Fig. 2). Based on EIT measurement, PP combined with PEEP-induced LRM increase ventilation distribution mainly in the dorsal region (5.0 vs. 2.0, P=0.015).R/I ratio was measured in 28 subjects. The higher R/I ratio was related with greater oxygenation improvement after LRM (140.50 vs 47.60,P=0.016). Conclusion: In patients with moderate to severe ARDS,PEEP-induced LRM combined with PP can improve survival. R/I may be useful to predict the response to LRM.