Summary: Introduction: High mechanical power is associated with mortality in patients who are critically ill and require invasive ventilation. It remains uncertain which components of mechanical power – volume, pressure or rate – increase mechanical power the most. Methods: We conducted a post hoc analysis of a database containing individual patient data from three randomised clinical trials of ventilation in patients without acute respiratory distress syndrome. The primary endpoint was mechanical power. We used linear regression; double stratification to create subgroups of participants; and mediation analysis to assess the impact of changes in volumes, pressures and rates on mechanical power. Results: A total of 1732 patients were included and analysed. The median (IQR [range]) mechanical power was 12.3 (9.3–17.1 [3.7–50.1]) J.min ^‐1 . In linear regression, respiratory rate (36%) and peak pressure (51%) explained most of the increase in mechanical power. Increasing quintiles of peak pressure stratified on constant levels of respiratory rate resulted in higher risks of high mechanical power (relative risk 2.2 (95%CI 1.8–2.6), p < 0.01), while decreasing quintiles of respiratory rate stratified on constant levels of peak pressure resulted in lower risks of high mechanical power (relative risk 0.2 (95%CI 0.2–0.3), p < 0.01). Mediation analysis showed that a reduction in respiratory rate, with the increase in tidal volume, partially mediates an effect of reduction in mechanical power (average causal mediation effect ‐0.10, 95%CI ‐0.12 to ‐0.09, p < 0.01), but still with a direct effect of tidal volume on mechanical power (average direct effect 0.15, 95%CI 0.11–0.19, p < 0.01). Discussion: In this cohort of patients without acute respiratory distress syndrome, pressure and respiratory rate were the most important determinants of mechanical power. The respiratory rate may be the most attractive ventilator setting to adjust when targeting a lower mechanical power.

Non-intubated patients with acute respiratory failure due to COVID-19 could benefit from awake proning. Awake proning is an attractive intervention in settings with limited resources, as it comes with no additional costs. However, awake proning remains poorly used probably because of unfamiliarity and uncertainties regarding potential benefits and practical application. To summarize evidence for benefit and to develop a set of pragmatic recommendations for awake proning in patients with COVID-19 pneumonia, focusing on settings where resources are limited, international healthcare professionals from high and low- and middle-income countries (LMICs) with known expertise in awake proning were invited to contribute expert advice. A growing number of observational studies describe the effects of awake proning in patients with COVID-19 pneumonia in whom hypoxemia is refractory to simple measures of supplementary oxygen. Awake proning improves oxygenation in most patients, usually within minutes, and reduces dyspnea and work of breathing. The effects are maintained for up to 1 hour after turning back to supine, and mostly disappear after 6–12 hours. In available studies, awake proning was not associated with a reduction in the rate of intubation for invasive ventilation. Awake proning comes with little complications if properly implemented and monitored. Pragmatic recommendations including indications and contraindications were formulated and adjusted for resource-limited settings. Awake proning, an adjunctive treatment for hypoxemia refractory to supplemental oxygen, seems safe in non-intubated patients with COVID-19 acute respiratory failure. We provide pragmatic recommendations including indications and contraindications for the use of awake proning in LMICs.

Driving pressure (ΔP) and mechanical power (MP) are associated with outcomes in critically ill patients, irrespective of the presence of Acute Respiratory Distress Syndrome (ARDS). INTELLiVENT-ASV, a fully automated ventilatory mode, controls the settings that affect ΔP and MP. This study compared the intensity of ventilation (ΔP and MP) with INTELLiVENT-ASV versus conventional ventilation in a cohort of COVID-19 ARDS patients in two intensive care units in the Netherlands. The coprimary endpoints were ΔP and MP before and after converting from conventional ventilation to INTELLiVENT-ASV. Compared to conventional ventilation, INTELLiVENT-ASV delivered ventilation with a lower ΔP and less MP. With conventional ventilation, ΔP was 13 cmH₂O, and MP was 21.5 and 24.8 J/min, whereas with INTELLiVENT-ASV, ΔP was 11 and 10 cmH₂O (mean difference –2 cm H2O (95 %CI –2.5 to –1.2 cm H₂O), p < 0.001) and MP was 18.8 and 17.5 J/min (mean difference –7.3 J/Min (95% CI –8.8 to –5.8 J/min), p < 0.001). Conversion from conventional ventilation to INTELLiVENT-ASV resulted in a lower intensity of ventilation. These findings may favor the use of INTELLiVENT-ASV in COVID-19 ARDS patients, but future studies remain needed to see if the reduction in the intensity of ventilation translates into clinical benefits.

Introduction: The driving pressure (ΔP) has an independent association with outcome in patients with acute respiratory distress syndrome (ARDS). INTELLiVENT-Adaptive Support Ventilation (ASV) is a closed-loop mode of ventilation that targets the lowest work and force of breathing. Aim: To compare transpulmonary and respiratory system ΔP between closed-loop ventilation and conventional pressure controlled ventilation in patients with moderate-to-severe ARDS. Methods: Single-center randomized cross-over clinical trial in patients in the early phase of ARDS. Patients were randomly assigned to start with a 4-h period of closed-loop ventilation or conventional ventilation, after which the alternate ventilation mode was selected. The primary outcome was the transpulmonary ΔP; secondary outcomes included respiratory system ΔP, and other key parameters of ventilation. Results: Thirteen patients were included, and all had fully analyzable data sets. Compared to conventional ventilation, with closed-loop ventilation the median transpulmonary ΔP with was lower (7.0 [5.0–10.0] vs. 10.0 [8.0–11.0] cmH₂O, mean difference − 2.5 [95% CI − 2.6 to − 2.1] cmH₂O; P = 0.0001). Inspiratory transpulmonary pressure and the respiratory rate were also lower. Tidal volume, however, was higher with closed-loop ventilation, but stayed below generally accepted safety cutoffs in the majority of patients. Conclusions: In this small physiological study, when compared to conventional pressure controlled ventilation INTELLiVENT-ASV reduced the transpulmonary ΔP in patients in the early phase of moderate-to-severe ARDS. This closed-loop ventilation mode also led to a lower inspiratory transpulmonary pressure and a lower respiratory rate, thereby reducing the intensity of ventilation. Trial registration Clinicaltrials.gov, NCT03211494, July 7, 2017. https://clinicaltrials.gov/ct2/show/NCT03211494?term=airdrop&draw=2&rank=1.

Objectives: The aim of this pilot study was to compare the amount of “mechanical power of ventilation” under adaptive support ventilation with nonautomated pressure-controlled ventilation. Design: Single-center, observational prospective pilot study adjoining unitwide implementation of adaptive support ventilation in our department. Setting: The ICU of a nonacademic teaching hospital in the Netherlands. Patients: Twenty-four passive invasively ventilated critically ill patients expected to need of invasive ventilation beyond the following calendar day. Measurements and Main Results: In patients under adaptive support ventilation, only positive end-expiratory pressure and Fio ₂ were set by the caregivers—all other ventilator settings were under control of the ventilator; in patients under pressure-controlled ventilation, maximum airway pressure (Pmax), positive end-expiratory pressure, Fio ₂, and respiratory rate were set by the caregivers. Mechanical power of ventilation was calculated three times per day. Compared with pressure-controlled ventilation, mechanical power of ventilation with adaptive support ventilation was lower (15.1 [10.5–25.7] vs 22.9 [18.7–28.8] J/min; p = 0.04). Tidal volume was not different, but Pmax (p = 0.012) and respiratory rate (p = 0.012) were lower with adaptive support ventilation. Conclusions: This study suggests adaptive support ventilation may have benefits compared with pressure-controlled ventilation with respect to the mechanical power of ventilation transferred from the ventilator to the respiratory system in passive invasively ventilated critically ill patients. The difference in mechanical power of ventilation is not a result of a difference in tidal volume, but the reduction in applied pressures and respiratory rate. The findings of this observational pilot study need to be confirmed in a larger, preferably randomized clinical trial.