Clinical Research On Non-invasive Positive Pressure Ventilation In Patients With Acute Lung Injury

ObjectiveNoninvasive positive pressure ventilation (NPPV) has been successfully used to treat various forms of acute respiratory failure. The role of non-invasive positive pressure ventilation in the treatment of acute lung injury (ALI) is controversial. The aims of this study were to assess the effect of NPPV, to identify specific risk factors for NPPV failure and to promote the selection of patients with ALI suitable for NPPV.MethodWe conducted a prospective cohort study of all patients admitted to the intensive care unit (ICU) of the First Affiliated Hospital of Bengbu Medical College from April 2007 to April 2010 with a diagnosis of ALI, in whom NPPV was initiated. The relevant data on admission were recorded, such as: age, gender, etiology of ALI , comorbidities, Acute Physiology And Chronic Health Evaluation (APACHE) II score,level of IPAP and EPAP .And outcomes included improvement of gas exchange, incidence of HAP after mechanical ventilation, duration of NPPV, ICU length of stay, hospital length of stay and prognosis. Respiratory rates(RR) and PaO₂/FiO₂ were recorded prior to the initiation, and within 2h , and discontinuation of NPPV. According to the treatment, patients were divided into success group and the failure group .We compared the two groups with the above information.Results:1.EPAP and APACHEII of successful group had significant statistical difference (P <0.01), and the number of cases with lung infection are also statistically significant (P <0.05), the values of PaO₂/FiO₂ and RR in different stages had different statistically significant which compared with failure group.The successful group more likely to have the following results:the more number of cases sustained to improve gas exchange , the longer duration of NPPV, the lower ICU mortality and the less number of HAP after ventilation, compared with failure group. The comparison of different stages in the same group:⑴RR and PaO₂/FiO₂ could continue to improve in the successful group.⑵there was no significant improvement of gas exchange observed in the failure group.RR in the failure group after NPPV 2h decreased significantly compared with before NPPV. PaO₂/FiO₂(0h)≤139 and PaO₂/FiO₂ (2h)≤151 were independently associated with NPPV failure.4. Most intubations occurred within the first 48 hours. More than half(56%)of the failure group were for hypoxemia or dyspnea.Conclusion:1. NPPV may be one of the effective and safe treatment methods for early ALI, and can be used as a first-line intervention for ALI except contraindications;2. PaO₂/FiO₂( 0h)≤139 and PaO₂/FiO₂ (2h)≤151 were independent risk factors for NPPV failure;3. Most intubations occurred within the first 48 hours;4.NPPV should be tried very cautiously or not at all in patients who have profound hypoxemia or can not continue to improve gas exchange and RR or have lung infection because they would fail NPPV.