Biotrauma during ultra-low tidal volume ventilation and venoarterial extracorporeal membrane oxygenation in cardiogenic shock: a randomized crossover clinical trial

Background Cardiogenic pulmonary oedema (CPE) may contribute to ventilator-associated lung injury (VALI) in patients with cardiogenic shock. The appropriate ventilatory strategy remains unclear. We aimed to evaluate the impact of ultra-low tidal volume ventilation with tidal volume of 3 ml/kg predicted body weight (PBW) in patients with CPE and veno–arterial extracorporeal membrane oxygenation (V–A ECMO) on lung inflammation compared to conventional ventilation. Methods A single-centre randomized crossover trial was performed in the Cardiac Intensive Care Unit (ICU) at a tertiary university hospital. Seventeen adults requiring V–A ECMO and mechanical ventilation due to cardiogenic shock were included from February 2017 to December 2018. Patients were ventilated for two consecutive periods of 24 h with tidal volumes of 6 and 3 ml/kg of PBW, respectively, applied in random order. Primary outcome was the change in proinflammatory mediators in bronchoalveolar lavage fluid (BALF) between both ventilatory strategies. Results Ventilation with 3 ml/kg PBW yielded lower driving pressures and end-expiratory lung volumes. Overall, there were no differences in BALF cytokines. Post hoc analyses revealed that patients with high baseline levels of IL-6 showed statistically significant lower levels of IL-6 and IL-8 during ultra-low tidal volume ventilation. This reduction was significantly proportional to the decrease in driving pressure. In contrast, those with lower IL-6 baseline levels showed a significant increase in these biomarkers. Conclusions Ultra-low tidal volume ventilation in patients with CPE and V–A ECMO may attenuate inflammation in selected cases. VALI may be driven by an interaction between the individual proinflammatory profile and the mechanical load overimposed by the ventilator. Trial registration The trial was registered in ClinicalTrials.gov (identifier NCT03041428, Registration date: 2nd February 2017).

Implementing nudges to promote utilization of low tidal volume ventilation (INPUT): a stepped-wedge, hybrid type III trial of strategies to improve evidence-based mechanical ventilation management

Background Behavioral economic insights have yielded strategies to overcome implementation barriers. For example, default strategies and accountable justification strategies have improved adherence to best practices in clinical settings. Embedding such strategies in the electronic health record (EHR) holds promise for simple and scalable approaches to facilitating implementation. A proven-effective but under-utilized treatment for patients who undergo mechanical ventilation involves prescribing low tidal volumes, which protects the lungs from injury. We will evaluate EHR-based implementation strategies grounded in behavioral economic theory to improve evidence-based management of mechanical ventilation. Methods The Implementing Nudges to Promote Utilization of low Tidal volume ventilation (INPUT) study is a pragmatic, stepped-wedge, hybrid type III effectiveness implementation trial of three strategies to improve adherence to low tidal volume ventilation. The strategies target clinicians who enter electronic orders and respiratory therapists who manage the mechanical ventilator, two key stakeholder groups. INPUT has five study arms: usual care, a default strategy within the mechanical ventilation order, an accountable justification strategy within the mechanical ventilation order, and each of the order strategies combined with an accountable justification strategy within flowsheet documentation. We will create six matched pairs of twelve intensive care units (ICUs) in five hospitals in one large health system to balance patient volume and baseline adherence to low tidal volume ventilation. We will randomly assign ICUs within each matched pair to one of the order panels, and each pair to one of six wedges, which will determine date of adoption of the order panel strategy. All ICUs will adopt the flowsheet documentation strategy 6 months afterwards. The primary outcome will be fidelity to low tidal volume ventilation. The secondary effectiveness outcomes will include in-hospital mortality, duration of mechanical ventilation, ICU and hospital length of stay, and occurrence of potential adverse events. Discussion This stepped-wedge, hybrid type III trial will provide evidence regarding the role of EHR-based behavioral economic strategies to improve adherence to evidence-based practices among patients who undergo mechanical ventilation in ICUs, thereby advancing the field of implementation science, as well as testing the effectiveness of low tidal volume ventilation among broad patient populations. Trial registration ClinicalTrials.gov, NCT04663802. Registered 11 December 2020.

Audit of low tidal volume ventilation in patients with hypoxic respiratory failure in a tertiary Australian intensive care unit

A low tidal volume ventilation (LTVV) strategy improves outcomes in patients with acute respiratory distress syndrome (ARDS). Subsequently, a LTVV strategy has become the standard of care for patients receiving mechanical ventilation. This strategy is poorly adhered to within intensive care units (ICUs). A retrospective analysis was conducted of prescribed tidal volumes in mechanically ventilated patients with hypoxic respiratory failure between April 2013 and March 2017. Data collection included the establishment of a new data-entry box for patient height in March 2016, aimed at assisting the calculation of LTVV. We reviewed 836 ICU admissions, comprising 19,884 hours of ventilation. A total of 92% of admissions lacked patient height recording. When height was recorded, 54% of hours of ventilation were LTVV adherent. Non-LTVV hours for both groups involved higher tidal volumes (38%) rather than lower tidal volumes (8%). Non–LTVV-adherent hours were significantly ( P<0.001) more likely to be associated with patient mortality than LTVV-adherent hours were. For all hours of ventilation, mean tidal volume before March 2016 was significantly higher (496 (standard deviation (SD) 101) ml, compared to after March 2016 (451 (SD 107) ml, P<0.001, 95% confidence interval for true difference in means 42 to 48 ml). However, this trend gradually reversed over time. There was a clinician preference for multiples of 50 ml. There was poor adherence to LTVV strategy in patients with hypoxic respiratory failure, which was associated with an increase in patient mortality. An electronic medical record intervention was successful in producing change, but this was not sustainable over time. Clinician ventilation prescribing habits were based on numerical simplicity rather than evidence-based practice.

Decapneization as supportive therapy for the treatment of status asthmaticus: a case report

Background Acute severe asthma is a life-threatening medical emergency. Characteristics of asthma include increased airway resistance and dynamic pulmonary hyperinflation that can manifest in dangerous levels of hypercapnia and acidosis, with significant mortality and morbidity. Severe respiratory distress can lead to endotracheal intubation followed by mechanical ventilation, which can cause increased air trapping with dynamic hyperinflation, predisposing the lungs to barotraumas. Case presentation The present case report describes the use of the minimally invasive ECCO2R ProLUNG® (Estor) with protective low-tidal-volume ventilation, in a Caucasian patient with near-fatal asthma and with no response to conventional therapy. Conclusions Since hypercarbia rather than hypoxemia is the primary abnormality in status asthmaticus, a rescue therapeutic strategy combining the ECCO2R membrane ProLUNG® (Estor) with ultra-protective low-tidal-volume ventilation can be successfully applied to limit the risk of severe barotrauma during invasive mechanical ventilation. ECCO2R ProLUNG® is a partial respiratory support technique that, based on the use of an extracorporeal circuit with a gas-exchange membrane, achieves relevant CO2 clearance directly from the blood using double-lumen venous-venous vascular access, at blood flow in the range of 0.4–1.0 L/minute.