ASV and lung-protective ventilation in ARDS patients


A recent study from the US found that settings targeted by ASV were consistent with lung-protective ventilation strategies in ARDS patients (1).

The researchers performed a randomized crossover trial in 17 mostly passive, moderate-to-severe ARDS patients to compare the automated settings in Adaptive Support Ventilation (ASV) mode with the hospital’s standard-of-care mode, adaptive pressure ventilation (APV). In ASV mode, the breathing frequency and tidal volume are automatically adjusted to maintain a set minute ventilation, while tidal volume (VT) was set to 6 ml/Kg IBW in APV mode according to the hospital’s standard of care. Patients were ventilated for 1–2 hours in each mode, maintaining a consistent minute ventilation.

The primary outcome was tidal volume (VT) corrected for ideal body weight. Overall, automated adjustment of VT in ASV resulted in just slightly higher VT (6.29 [5.87–6.99] mL/kg IBW vs 6.04 [6.01–6.06] mL/kg IBW, P = .035). The authors noted that while statistically significant, this difference was too small in absolute terms to be considered clinically relevant. Of greater importance was the fact that VT remained at all times under 8 mL/kg and thus within the generally accepted lung-protective range. In addition, VT in ASV was found to be lower in a subset of patients with low compliance and a short RCexp, indicating individual titration according to the patient’s respiratory mechanics.

In terms of secondary outcomes, frequency in ASV was marginally lower, while plateau pressures, driving pressures, and mechanical power were similar in both modes. However, mechanical power was found to be lower in ASV mode in the patients with lower compliance, and particularly in those where VT was also reduced.

The results show that the settings in ASV were consistent with lung-protective strategies. In addition, ASV adjusted VT according to the patient’s respiratory mechanics, with lower VT and mechanical power being delivered in subjects with stiffer lungs.


  1. Baedorf Kassis EN, Bastos AB, Schaefer MS, Capers K, Hoenig B, Banner-Goodspeed V, Talmor D. Adaptive Support Ventilation and Lung-Protective Ventilation in ARDS. Respir Care. 2022 Aug 16:respcare.10159. doi: 10.4187/respcare.10159. Epub ahead of print. PMID: 35973716.

Date of Printing: 28.09.2022
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