TL;DR: ⚪ Clean equivalence — allowing early spontaneous ventilation (PC-SV) vs conventional volume assist-control gave identical hospital mortality (34.6% vs 33.5%, P=0.77) with matched lung-protective targets.
1. Publication
- Title: Pressure control plus spontaneous ventilation versus volume assist-control ventilation in acute respiratory distress syndrome. A randomised clinical trial
- Acronym: None assigned
- Year & Journal: Intensive Care Medicine, 2024;50(10):1647-1656
- Citation: Richard JC, Beloncle FM, Béduneau G, et al. Intensive Care Med. 2024;50(10):1647-1656. doi:10.1007/s00134-024-07612-3
2. Context & Rationale
Background: Preserving spontaneous breathing during ARDS ventilation may improve diaphragm function and ventilation-perfusion matching, but risks patient-self-inflicted lung injury (P-SILI) if effort is excessive. Whether a pressure-controlled strategy allowing early, non-synchronized spontaneous ventilation (PC-SV) improves outcomes compared with conventional volume assist-control (ACV) was untested at scale.
Research Question/Hypothesis: In adults with moderate-severe ARDS, does PC-SV (allowing spontaneous ventilation from early in the course) reduce in-hospital mortality at day 60 compared with conventional ACV?
3. Design & Methods
- Study Type: Open-label RCT
- Setting & Centers: 22 ICUs, France; February 2013–October 2018
- Population: 700 adults with moderate-severe ARDS (PaO2/FiO2 <200 mmHg)
- Intervention: PC-SV — pressure-controlled ventilation allowing non-synchronized unassisted spontaneous ventilation (n=348); paralysis stopped after 24h, sedation adapted to favor spontaneous ventilation
- Comparator: ACV — conventional volume assist-control (n=352); same Vt (6 mL/kg PBW) and PEEP targets
- Statistical Power & Follow-Up: Primary: in-hospital death from any cause at day 60.
4. Key Results
700 patients randomized (348 PC-SV, 352 ACV).
Outcome | PC-SV | ACV | Effect Size | 95% CI | p-value | Notes |
Hospital mortality (primary) | 34.6% | 33.5% | RR 1.03 | 0.84–1.27 | 0.77 | Clear null |
28-day mortality | No significant difference | No significant difference | — | — | — | Consistent with primary |
5. Internal Validity Assessment
Large (700-patient), multicenter RCT with matched tidal volume/PEEP targets between arms, isolating the spontaneous-vs-controlled ventilation question specifically. Overall: Strong — well-powered, clean null result with matched lung-protective targets in both arms ensuring a genuine, isolated test of the ventilation-mode question rather than confounded by differing tidal volume/PEEP strategies.
6. External Validity Assessment
French, 22-center, moderate-severe ARDS population — broadly representative of general ARDS populations eligible for early spontaneous-breathing strategies.
7. Strengths & Limitations
Strengths: Large, multicenter, well-matched design (same Vt/PEEP targets in both arms); addresses a genuine, long-debated question (early spontaneous vs controlled ventilation in ARDS) with a definitive sample size.
Limitations: Open-label design; long enrollment period (2013-2018) may introduce temporal practice heterogeneity; a subsequent scoping review notes distinguishing spontaneous vs controlled ventilation approaches in critical care remains conceptually and methodologically challenging.
8. Interpretation & Practice Impact
Does not support routine early transition to spontaneous ventilation (via PC-SV) over conventional volume assist-control in moderate-severe ARDS — both approaches produce statistically equivalent mortality when lung-protective targets are matched.
9. Controversies & Subsequent Evidence
A 2025 scoping review ("Spontaneous Versus Controlled Mechanical Ventilation in Patients With ARDS") cites this trial as a key data point in the broader, still-evolving literature on assisted vs controlled ventilation modes in ARDS, alongside related physiological studies on respiratory drive and effort during the transition from controlled to spontaneous ventilation.
10. Summary & Executive Takeaway
Summary: This French multicenter RCT randomized 700 adults with moderate-severe ARDS to PC-SV (early spontaneous ventilation) or conventional ACV, with matched tidal volume and PEEP targets. Hospital mortality was equivalent (34.6% vs 33.5%, RR 1.03, P=0.77).
Overall Takeaway: Allowing early, non-synchronized spontaneous ventilation via a pressure-controlled strategy produces equivalent mortality to conventional volume assist-control ventilation in moderate-severe ARDS when lung-protective targets are matched — neither approach demonstrates superiority, supporting clinician/institutional preference-based mode selection within lung-protective parameters.
11. Bibliography
- Yoshida T, Rinka H, Kaji A, et al. The impact of spontaneous ventilation on distribution of lung aeration in ARDS. Anesth Analg. 2009;109(6):1892-1900.
- Balzani E, Murgolo F, Pozzi M, et al. Respiratory Drive, Effort, and Lung-Distending Pressure during Transitioning from Controlled to Spontaneous Ventilation in ARDS. J Clin Med. 2024;13(17):5227.