The Application Of NAVA In The Patients Of ARDS

Acute respiratory distress syndrome (ARDS) was a clinical critical disease, which main clinical manifestations were hypoxemia。And the main pathogeny of this disease were severe infection, trauma, shock.The general treatment was very difficult to rectify hypoxemia.Mechanical ventilation was the main method in treatment of this disease.Over the years, many attempts were treated with mechanical ventilation in ARDS.With a variety of mechanical ventilation modes was applicated in clinical work, treatment of ARDS had clear progress.Those previous mechanical ventilation modes could hardly to improve alveoli collapse, low tidal volume and the best PEEP in ARDS.The ecruitment maneuver(RM),which Put forward in recent years,could effectively reduce the extravascular lung water, recruitment of alveolar collapse and improve oxygenation.However, it could not effective avoid ventilator-induced lung injury (VILI) and lung injury due to the poor patient-ventilator asynchrony.Many problems still exist in the traditional mechanical ventilation mode,as high airway pressure, poor patient-ventilator asynchrony, delay of triggering time. All of these could lead to lung injury (VILI), respiratory muscle increased work, respiratory muscle fatigue, final result difficult weaning, and treatment failure.At the same time, during the outcome in ARDS patients on breathing, the respire requirement of human body can change at any time, the corresponding mechanical ventilation conditions should also be changed with it.Conventional mechanical ventilation could not solve these problems.We hope to solve that how to achieve the lowest effective pressure and prevent alveolar collapse; how to further reduce lung injury through improve patient-ventilator synchrony; how to retain patient’s own breathing and how to adjust the tidal volume with the prognosis and demand of patients.Neurally adjusted ventilatory assist(NAVA) was different from the traditional mode of mechanical ventilation in the past.This mode trigger mechanical ventilation directly by respiratory nerve impulses, through monitoring electrical activity of diaphragm (electrical activity of diaphragm, EAdi) signal.Because of the monitoring was the nerve impulses, it could effectively shorten the trigger delay, patient-ventilator achieve better synchronization, reduce lung injury, and reduce the work of breathing.Also this model could keeping autonomous respiration As large as possible,and change the tidal volume with the patient’s needs. Compared with. traditional mechanical ventilation modes, this mode was more intelligent, and more suited to human physiological needs.OBJECTIVETo compare the differences of patient-ventilator synchrony, respiratory mechanics, gas exchange capacity and hemodynamic in patients of acute respiratory distress syndrome (ARDS), with use of neurally adjusted ventilatory assist (NAVA) or traditional press support ventilation (like PSV).METHODSThis study was based on30patients of acute respiratory distress syndrome (ARDS),Which were randomly divided into two groups,15in NAVA group and15in control group.Hemodynamic data were detected in using PICCO (HR, CI, CVP, ELWI, GEDI); other data, which in patient-ventilator synchronization (Trigger delay, Off cycle delay), respiratory mechanics (PIP, Pmean), gas exchange capacity (arterial blood pH, PaO2, PaCO2, oxygenation index), weaning time, APACHEII score,were detected in corresponding monitor.RESULTSTo compared hemodynamic data, HR did not change significantly in two groups. CI were increased (P<0.05), but there were no significant difference (P>0.05)between the two groups.CVP were increased (P<0.05), but was lower in group NAVA than in group PSV (P<0.05). Extravascular lung water content index (ELWI) were all significantly decreased (P<0.05), but there were no significant difference (P>0.05) between the two groups.GEDI were not significantly changed.In synchrony (Trigger delay, Off cycle delay (PIP), respiratory mechanics, Pmean) offline time and APACHEII score, NAVA group was significantly better than that in PSV group, and there was significant difference (P<0.05).To compared exchange capacity in gas (arterial blood pH, PaO2, PaCO2, oxygenation index), NAVA group had better oxygenation index with PSV group(P<0.05).CONCLUIONS In treatment of Acute respiratory distress syndrome patients with mechanical ventilation, NAVA mode as well as PSV mode could improve the hemodynamics. The effect on CVP in NAVA mode was better than PSV mode.NAVA mode can obviously improve patient-ventilator synchrony, increase lung compliance, improve respiratory mechanics, reduce the work of breathing, Shorten the offline time,Therefore NAVA ventilation mode was better than PSV ventilation mode.