Current Practices of Prone Positioning in ARDS Reported by European ICU Clinicians (CUPIDO)-A Cross-Sectional...

Background: Prone positioning improves survival in patients with moderate to severe acute respiratory distress syndrome (ARDS), yet its implementation in routine clinical practice remains poorly characterized. We conducted a survey to assess contemporary prone positioning practices and their heterogeneity in the management of ARDS across European intensive care units (ICUs). Methods: A cross-sectional, questionnaire-based survey was conducted among clinicians involved in ARDS management between March and August 2025. The survey was developed by a panel of experts in intensive care medicine and underwent testing for face and content validity prior to dissemination. The questionnaire was distributed through European networks, including the European Society of Intensive Care Medicine (ESICM), the PROtective VEntilation Network (PROVE Network), the European Society of Anaesthesiology and Intensive Care (ESAIC), and national societies. Results: Out of 592 eligible responses, 451 responses were complete and from European clinicians (66.1% male), with the largest contributions being from Italy (28.6%), Germany (18.4%) and Austria (11.5%). Of these, 446 respondents (98.9%) reported performing prone positioning. Initiation thresholds for prone positioning varied, most commonly a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂) ≤ 150 mmHg (55.4%), followed by ≤100 mmHg (26.9%), ≤200 mmHg (11.4%), and ≤300 mmHg (1.8%). Full prone positioning was reported as always or often used by 38.6% and 37.7% of participants, whereas semi-prone positioning (7.0% and 21.1%) or lateral positioning (2.5% and 14.8%) was used less often. The duration of prone positioning varied: 47.8% reported 16 h, 17.0% 12 h and 7.8% 8 h per session. Conclusions: Among self-selected clinicians working in European ICUs, prone positioning was commonly reported, though reported practice varied with respect to initiation thresholds, prone positioning strategy and duration. These findings identify specific areas where practice diverges and where current guidance and evidence remain incomplete.