Lung-protective ventilation strategy in acute respiratory distress syndrome: a critical reappraisal of current practice

Park Critical Care (2025) 29:444 https://doi.org/10.1186/s13054-025-05675-2 Critical Care Open Access REVIEW Lung-protective ventilation strategy in acute respiratory distress syndrome: a critical reappraisal of current practice Kwang Joo Park1* Abstract Recognition of ventilator-induced lung injury has led to the development of lung-protective ventilation strategies, significantly influencing the management of acute respiratory distress syndrome (ARDS). By the end of the 20th century, five randomized controlled trials had compared the survival benefits of low tidal volume (VT) ventilation with those of traditional high VT ventilation. Two studies demonstrated favourable outcomes, most notably the landmark ARDS Network trial, which established the widely recommended VT of 6 mL/kg predicted body weight. However, the universal application of a fixed VT has been controversial, with poor adherence in clinical practice. The two trials used a greater contrast in VTs (6 vs. 12 mL/kg) than did the others (7–11 mL/kg) and incorporated methodological extremes, including toleration of elevated airway pressures or encouragement of unnecessary increases. In addition, disparities in underlying aetiologies and ventilatory parameters, such as unbalanced positive end-expiratory pressure and respiratory rates, may have influenced the results. There is no conclusive evidence to support the superiority of 6 mL/kg over intermediate VTs (7–10 mL/kg). Many subsequent studies have suggested that VT requirements should be individualized on the basis of lung mechanics and physiological status. The benefits of the current recommendations may be limited by factors such as the severity of hypoxemia, lung compliance, dead-space fraction, and inaccuracies in formula-based lung volume estimation. The goal of mechanical ventilation in ARDS patients is supportive rather than curative; therefore, a moderate approach is recommended in clinical practice. Further studies are needed to establish an individualized, patient-centred approach that allows more flexible and moderate settings. Keywords Acute respiratory distress syndrome, Lung-protective strategy, Low tidal volume ventilation, Ventilatorinduced lung injury, Individualized strategy *Correspondence: Kwang Joo Park 1 Department of Pulmonary and Critical Care Medicine, Ajou University School of Medicine, 164 World cup-ro, Suwon, Gyeonggi-do 16499, South Korea © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Low VT High VT Low VT Stewart, et al. [12] Amato, et al. [9] Low VT High VT ARDSNet [13] 861 52 53 120 116 Specific protocol combinations of PEEP and FIO2 Specific protocol combinations of PEEP and FIO2 2 cmH2O higher than Pflex 9.4 ± 3.6 8.6 ± 3.6 9.5§ 8.2§ 6.9 ± 0.8 16.3 ± 0.7 8.6 ± 3.0 7.2 ± 3.3 10.7 ± 2.9 10.7 ± 2.3 IBW‡ BW IBW Body weight measure applied DBW 6–10 10–15 ≤8 10–15 ≤ 6* 12* 7.1 ± 1.3 10.3 ± 1.7 7.0 ± 0.7 10.7 ± 1.4 Ppeak ≤ 30 Ppeak ≤ 50 Pplat ≤ 25-30 Ppeak ≤ 60 8.1 ± 3.4 9.1 ± 4.2 6.8§‖ 6.0§‖ 25 ≤ Pplat ≤ 30 45 ≤ Pplat ≤ 50 Pplat ≤ 30 Pplat ≤ 45–55 13.2 ± 0.4¶ Pdriv < 20, Ppeak < 40 9.3 ± 0.5¶ None 9.6 ± 3.9 8.0 ± 3.6 9.6 ± 3.0 8.5 ± 2.8 25 ± 7 33 ± 9 26.5§ 30.5§ 34.4 ± 1.9 31.8 ± 1.4 22.3 ± 5.4 26.8 ± 6.7 26 ± 7 37 ± 9 23.9 ± 0.7¶ 37.8 ± 1.2¶ 23§‖ 29§‖ 20.0 ± 4.7 28.6 ± 7.2 In-hospital mortality In-hospital mortality 28-d mortality In-hospital mortality Significant NS Significant NS < 30/min, allowed PaCO2 limit: 80 mmHg 10–24/min, adjusted to maintain PaCO2 at 35–38 mmHg Adjusted to maintain PaCO2 at 30–45 mmHg None Adjusted to maintain PaCO2 at 38–42 mmHg 5–35/min, adjusted to maintain PaCO2 at 35–45 mmHg Resp. rate (/min) Rule for setting 7.3§‖ 10.2§‖ 6.5 ± 1.4 Adjusted to maintain pH at 7.3–7.45 11.4 ± 1.4 Primary Survival Pplat (cmH2O) outcome of analysis Day 1 Day 7 interest 25.7 ± 5.0 24.5 ± 5.7 60-d mortality NS 31.7 ± 6.6 30.5 ± 9.4 7.37 ± 1.3 10.7 ± 1.8 6.8 ± 0.6 10.1 ± 1.4 Tidal volume (ml/kg) Target Actual, Actual, Day 1 Day 7 5–8 7.8§ 10–12 10.2§ PBW‡ 6 (4–8) 6.2 ± 0.9 12 11.8 ± 0.8 Set pressure limit (cmH2O) Day 1 Day 7 26 26 432 429 58 58 60 60 29 24 Increments of 5 mH2O (0–15) for the greatest improvement in oxygenation or the first level allowing PaO2/FIO2 >200 mmHg 5–20 cmH2O, increments of 2.5 cmH2O to maintain the FiO2 ≤ 0.5, SaO2 = 89–93% PEEP (cmH2O) Rule for setting May 2000 Low VT High VT Low VT High VT Low VT High VT Low VT High VT Low VT High VT Sub-groups No. subjects Total Subgroup – – 24.9 ± 6.5 19.2 ± 4.7 21.4† 18.8† Day 7 If pH was < 7.30, permissible; if pH was < 7.20, ≥ 10 mEq/h Applied, but not described If pH ≤ 7.0, 2 mmol/kg every four h (up to three doses) If pH < 7.2, 50 mmol/h – – – – 29 ± 7 30 ± 7 16 ± 6 20 ± 7 Administration of Na bicarbonate If pH < 7.05 – – 22.1 ± 6.2 15.6 ± 5.0 19.3† 15.9† Day 1 (2025) 29:444 * These levels were strictly maintained with minimal variations according to the study design, although actual tidal volumes cannot be presented without body weight data; †estimated from tidal volume and minute volume data; ‡Devine’s formula; §visually estimated values from the figures; ‖values on Day 5; ¶ mean values on Days 2–7 Data are presented as numbers (n) and means ± SEMs (Amato and Brower studies) or means ± SDs (the other three studies). ARDS, acute respiratory distress syndrome; ARDSNet, ARDS Network; VT, Tidal volume; Low VT, low-tidal-volume ventilation group; High VT, high-tidal-volume ventilation group; DBW, dry body weight; IBW, ideal body weight; BW, body weight; PBW, predicted body weight; Resp. rate, respiratory rate; PEEP, positive end-expiratory pressure; Pplat, plateau airway pressure; Ppeak, peak airway pressure; Pdriv, driving pressure (Pplat – PEEP); NS, not significant; Pflex, the lower inflection point on the inspiratory pressure–volume curve; Na bicarbonate, sodium bicarbonate Low VT High VT Brower, et al. [11] High VT Low VT High VT Brochard, et al. [10] Mar 1996 – Mar 1999 ARDSNet [13] Subgroups May 2, 1994 – Mar Aug 1999 1, 1996 Brower et al. [11] Studies (first author) Dec 1990 – July 1995 Amato, et al. [9] Feb 5, 1998 Feb 5, 1998 July 1995 – Sep (...truncated)