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. 2025 May 7;13(1):24.
doi: 10.1186/s40560-025-00795-x.

The effects of prolonged prone positioning on response and prognosis in patients with acute respiratory distress syndrome: a retrospective cohort study

Yuhang Yan #  1   2 , Junying Bao #  1   3 , Shumin Cai #  1 , Xiangning Zhong  1   2 , Bingxuan Geng  1 , Jingyi Liang  1 , Zhiya Deng  1 , Zhongqing Chen  1 , Zaisheng Qin  4 , HongBin Hu  5 , Zhenhua Zeng  6
Affiliations

The effects of prolonged prone positioning on response and prognosis in patients with acute respiratory distress syndrome: a retrospective cohort study

Yuhang Yan et al. J Intensive Care. .

Abstract

Background: Prone positioning improves outcomes in patients with acute respiratory distress syndrome (ARDS), but the optimal duration in critical care settings remains uncertain. This study aims to evaluate the investigates the impact of prone ventilation duration on clinical outcomes.

Methods: This retrospective study was conducted on ARDS patients admitted to the intensive care unit (ICU), Nanfang hospital of Southern Medical University, who received prone positioning. Patients were categorized into two groups: the prolonged prone positioning (PPP) (≥ 16 h) group and the standard prone positioning (SPP) (< 16 h) group. Propensity score matching (PSM) was employed to balance baseline characteristics. Cox proportional hazards, regression models were utilized to evaluate the association between the prone duration and clinical outcomes. Kaplan-Meier survival curves were generated to compare 28-day mortality, with log-rank tests analyzing differences. Restricted cubic spline (RCS) were applied to investigate the time-response between prone duration, PaCO₂, PaO₂, positive end-expiratory pressure, response rate, and 28-day mortality. In addition, the incidence of prone position-related complications was assessed in both groups.

Results: A total of 234 patients with ARDS were included, with an overall 28-day mortality of 49.1% (115/234). After PSM, 81 matched pairs were compared. The PPP group had lower 28-day mortality (46.9% vs. 53.1%; hazard ratios (HR): 0.53; 95% CI 0.32-0.85; P = 0.033) and improved prone positioning response rate [70.5% vs. 60.5%; odds ratio (OR): 1.46; 95% CI 1.23-1.89; P = 0.025]. RCS analysis suggested a reduction in mortality with prone durations ≥ 16 h, and longer durations correlated with better prone response. However, no significant association was found between PPP and reduced ICU or hospital length of stay. RCS analysis indicated a gradual decrease in 28-day mortality with increasing duration of prone positioning, and longer duration were associated with a higher likelihood of a prone response. There were no significant differences in prone ventilation-related complications between the two groups.

Conclusions: PPP (≥ 16 h) is associated with reduced 28-day mortality and improved response rates in ICU patients with ARDS, without increasing complication risks. Prospective studies are needed to further validate these results.

Keywords: Acute respiratory distress syndrome; Intensive care unit; Prognosis; Prolonged prone position; Response rates.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: The study was approved by the Ethics Commission of Nanfang Hospital (NFEC-202312-K61). The Ethics Commission of Nanfang Hospital waived the requirement for obtaining informed consent. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Enrollment process of ARDS patients underwent prone positioning. ARDS acute respiratory distress syndrome, ICU intensive care unit, PSM propensity score matching
Fig. 2
Fig. 2
Kaplan–Meier curves of the PPP group and the SPP group before and after propensity score matching. A Kaplan–Meier curve for 28-day mortality according to prone duration before propensity score matching. B Kaplan–Meier curve for 28-day mortality according to prone duration after propensity score matching
Fig. 3
Fig. 3
The time–response relationship association between duration of prone session, PaCO2, PaO2, PEEP and 28-day mortality. Cubic spline curves are shown as a solid line, with the shaded area representing the 95% CI. A The time–response relationship association between duration of prone session and 28-day mortality; B The time–response relationship association between PaCO2 and 28-day mortality; C The time–response relationship association between PaO2 and 28-day mortality; D The time–response relationship association between PEEP and 28-day mortality. PEEP positive end-expiratory pressure, HR hazard ratio, CI confidence interval
Fig. 4
Fig. 4
Time–response relationship between duration of prone session, PaCO2, PaO2, PEEP and response rate. Cubic spline curves are shown as a solid line, with the shaded area representing the 95% CI. A Time–response relationship association between duration of prone session and response rate; B time–response relationship association between PaCO2 and response rate; C time–response relationship association between PaO2 and response rate; D time–response relationship association between PEEP and response rate. PEEP positive end-expiratory pressure, OR odds ratio, CI confidence interval
Fig. 5
Fig. 5
Association between the duration of prone session, 28-day mortality and response rate in subgroups. A Association between the duration of prone session and 28-day mortality in subgroups. B Association between the duration of prone session and response rate in subgroups. ARDS acute respiratory distress syndrome, OR odds ratio, CI confidence interval
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