Lung-protective Ventilation in Patients with Brain Injury： A Multicenter Cross-sectional Study and Questionnaire Survey in China

Background： Over the years, the mechanical ventilation （MV） strategy has changed worldwide. The aim of the present study was to describe the ventilation practices, particularly lung-protective ventilation （LPV）, among brain-injured patients in China. Methods： This study was a multicenter, 1-day, cross-sectional study in 47 Intensive Care Units （ICUs） across China. Mechanically ventilated patients （18 years and older） with brain injury in a participating ICU during the time of the study, including traumatic brain injury, stroke, postoperation with intracranial tumor, hypoxic-ischemic encephalopathy, intracranial infection, and idiopathic epilepsy, were enrolled. Demographic data, primary diagnoses, indications for MV, MV modes and settings, and prognoses on the 60th day were collected. Multivariable logistic analysis was used to assess factors that might affect the use of LPV. Results： A total of 104 patients were enrolled in the present study, 87 （83.7%） of whom were identified with severe brain injury based on a Glasgow Coma Scale 〈8 points. Synchronized intermittent mandatory ventilation （SIMV） was the most frequent ventilator mode, accounting for 46.2% of the entire cohort. The median tidal volume was set to 8.0 ml/kg （interquartile range [IQR], 7.0-8.9 ml/kg） of the predicted body weight; 50 （48.1%） patients received LPV. The median positive end-expiratory pressure （PEEP） was set to 5 cmH20 （IQR, 5-5 cmH20）. No PEEP values were higher than 10 cmH20. Compared with partially mandatory ventilation, supportive and spontaneous ventilation practices were associated with LPV. There were no significant differences in mortality and MV duration between patients subjected to LPV and those were not. Conclusions： Among brain-injured patients in China, SIMV was the most frequent ventilation mode. Nearly one-half of the brain-injured patients received LPV. Patients under supportive and spontaneous ventilation were more likely to receive LPV.

Driving pressure decoded:Precision strategies in adult respiratory distress syndrome management

Mechanical ventilation(MV)is an important strategy for improving the survival of patients with respiratory failure.However,MV is associated with aggravation of lung injury,with ventilator-induced lung injury(VILI)becoming a major concern.Thus,ventilation protection strategies have been developed to minimize complications from MV,with the goal of relieving excessive breathing workload,improving gas exchange,and minimizing VILI.By opting for lower tidal volumes,clinicians seek to strike a balance between providing adequate ventilation to support gas exchange and preventing overdistension of the alveoli,which can contribute to lung injury.Additionally,other factors play a role in optimizing lung protection during MV,including adequate positive end-expiratory pressure levels,to maintain alveolar recruitment and prevent atelectasis as well as careful consideration of plateau pressures to avoid excessive stress on the lung parenchyma.

Progress of mechanical power in the intensive care unit

Mechanical power of ventilation,currently defined as the energy delivered from the ventilator to the respiratory system over a period of time,has been recognized as a promising indicator to evaluate ventilator-induced lung injury and predict the prognosis of ventilated critically ill patients.Mechanical power can be accurately measured by the geometric method,while simplified equations allow an easy estimation of mechanical power at the bedside.There may exist a safety threshold of mechanical power above which lung injury is inevitable,and the assessment of mechanical power might be helpful to determine whether the extracorporeal respiratory support is needed in patients with acute respiratory distress syndrome.It should be noted that relatively low mechanical power does not exclude the possibility of lung injury.Lung size and inhomogeneity should also be taken into consideration.Problems regarding the safety limits of mechanical power and contribution of each component to lung injury have not been determined yet.Whether mechanical power-directed lung-protective ventilation strategy could improve clinical outcomes also needs further investigation.Therefore,this review discusses the algorithms,clinical relevance,optimization,and future directions of mechanical power in critically ill patients.

Ventilation practices in burn patients—an international prospective observational cohort study

Background:It is unknown whether lung-protective ventilation is applied in burn patients and whether they benefit from it.This study aimed to determine ventilation practices in burn intensive care units(ICUs)and investigate the association between lung-protective ventilation and the number of ventilator-free days and alive at day 28(VFD-28).Methods:This is an international prospective observational cohort study including adult burn patients requiring mechanical ventilation.Low tidal volume(V_(T))was defined as V_(T)≤8 mL/kg predicted body weight(PBW).Levels of positive end-expiratory pressure(PEEP)and maximum airway pressures were collected.The association between V_(T) and VFD-28 was analyzed using a competing risk model.Ventilation settings were presented for all patients,focusing on the first day of ventilation.We also compared ventilation settings between patients with and without inhalation trauma.Results:A total of 160 patients from 28 ICUs in 16 countries were included.Low V_(T) was used in 74%of patients,median V_(T) size was 7.3[interquartile range(IQR)6.2–8.3]mL/kg PBW and did not differ between patients with and without inhalation trauma(p=0.58).Median VFD-28 was 17(IQR 0–26),without a difference between ventilation with low or high V_(T)(p=0.98).All patients were ventilated with PEEP levels≥5 cmH_(2)O;80%of patients had maximum airway pressures<30 cmH_(2)O.Conclusion:In this international cohort study we found that lung-protective ventilation is used in the majority of burn patients,irrespective of the presence of inhalation trauma.Use of low V_(T) was not associated with a reduction in VFD-28.Trial registration:Clinicaltrials.gov NCT02312869.Date of registration:9 December 2014.