The Relationship Of Extravascular Lung Water And Prognosis In Acute Respiratory Distress Syndrome:an Observational Study

Objectives:To investigate the effect of extravascular lung water index and pulmonary vascular index on the prognosis of ARDS patients during hospitalization.Methods:The retrospective analysis were made on demographics, clinical indicators and supporting test results of 69 patients from the ICU of Qilu Hospital of Shandong University from January,2010 to December,2014. The cases were in accord with Berlin diagnostic criteria consistent with ARDS, age≥18 years, hospitalization time in ICU≥72 hours.The patients were divided into death group and survival group according to the prognosis. The clinical data were divided into the following four parts:(1)The enrolled roadmap of ARDS patients. (2) The clinical baseline characteristics of patients in accord with Berlin diagnostic criteria was observed.(3) The relationship between prognosis and the cause, type, degree and mechanical ventilation setting parameters of ARDS. (4) The relationship between prognosis and the fluid balance, PICCO monitoring indicators (EVLWI, PVPI) of patients.(5)In this process, the age, gender, underlying diseases, ARDS patients origin, APACHE II score, the incidence of septic shock, lactate levels, albumin, HCT, bilirubin albumin, BUN, CR, NT -proBNP levels, CRP levels, duration of mechanical ventilation, the hospitalization in ICU, the total length of hospitalisation,the fluid balance at 24 hours,48 hours,72 hours,1 week, MODS or not, ARDS classification, EVLWI and prognosis were compared between two groups.Results:(1) Clinical data:A retrospective analysis was made on clinical data of 69 patients(46 male,23 female).44 cases were lung-derived and 25 cases were extrapulmonary according to the type of ARDS.28 patients survived and 41 patients died after 28days(Figure 1).(2) Baseline data were compared in different prognosis groups.The survival group and death group:The age:(50.25±17.27) vs (61.02±17.09), p=0.013.BMI:(25.7±3.4)kg/m2 vs (23.3±3.8) kg/m2, P=0.007. Immunocompromised:(1/28) vs (13/41), P=0.004. Internal diseases:(5/28) vs (20/41), P=0.029. The incidence of septic shock:(18/28) vs (37/41), P=0.006. AKI (15/28) vs (32/41), P=0.032. BNP (3936.54±3986.89) pg/ml vs (12270.56±12908.37) pg/ml, P=0.004. SOFA: (9.11±2.22) vs (10.73±3.57), P=0.036.The death group and survival group had significant difference.The sex, smoking, alcohol drinking, body temperature, WBC, CRP, PCT, APACHE2 score, bilirubin, albumin, HCT, BUN, CR, hypertension, diabetes, chronic kidney disease and other underlying diseases and clinical parameters showed no significant difference (Table 1).(3) The relationship between prognosis and classification and severity of ARDS. The survival group and death group:lung injury score:(2.74±0.66) vs (3.36±0.65),P=0.000. Pulmonary ARDS(12/25) vs (32/44),P= 0.003.ARDS severity(9/28) vs (31/41),P=0.001, The death group and survival group had significant difference. The parameters of mechanical ventilation and blood gas analysis parameters:Tidal volume:VT/PBW(7.8±1.1)ml/kg vs (7.5±1.3)ml/kg,P=0.253. The incidence of complications of mechanical ventilation of tension pneumothorax:(1/28) vs (5/41),P0.416. PEEP:(9.0±4.37) cmH2O vs (11.10±4.84)cmH2O, P=0.07 and PH, lactic acid showed no significant difference.PCO2(38.07±9.84)mmHg vs(45.12±18.74)mmHg,P=0.046, oxygenation index (143.52±60.01)mmHg vs (87.89±44.00)mmHg,P=0.000, PIP:(24.82± 5.82)cmH2O vs (29.41±7.31) cmH2O,P=0.005.(Table 2). The death group and survival group had significant difference. ARDS patients mild (10/69), moderate (19/69), and severe (40/69).The prognosis of the higher the ARDS grade level was worse and with higher mortality rate.(4)The relationship between prognosis of patients with ARDS and the fluid balance of patients admitted to hospital within 1 week,EVLWI and PVPI. The survival group and death group:The fluid balance on the first day(2618±2503)ml vs (1529±1868) ml, P=0.042. The fluid balance in lweek:(4442±5976) ml vs (7270±4456) ml,P=0.045. The fluid balance on the first day(d1) and the fluid balance in lweek showed significant difference.The GEDI、ITBI of the death group and survival group had no significant difference on d1、d2、d3. The fluid balance on d2、d3 showed significant difference. D1(the survival group and death group):ELWI:(12.5±7.6)ml/kg vs(18.2± 8.3) ml/kg,P=0.005.D2:ELWI(12.4±8.5)ml/kg vs(19.2±9.7) ml/kg,P=0.003.D3:ELWI:(12.3± 5.2)ml/kg vs (20.01±1.6)ml/kg, P=0.002.Dl:PVPI:(2.4±1.2)vs(3.6±1.6), P=0.001. D2:PVPI:(2.3 ±1.3)vs(3.6±1.7),P=0.001.D3:PVPI:(2.1±0.9vs(3.9±2.0),P=0.000.The death group and survival group had significant difference. The ELWI, PVPI of patients of surviving group had a clear downward trend within 72 hours, but the death group had an increasing trend. (Table 3).(5) The mortality of ARDS(41/69,59.42%), total hospitalization time:(48.18±25.56) days vs (21.21±19.56) days, P=0.000, the days in ICU:(29.62±25.50) days vs (12.56±15.85) days, P =0.003, non-mechanical ventilation within 28 days:(17.64±7.80) days vs 0 day, P=0.000]. The survival group and death group had significant difference. The mechanical ventilation (12.72± 15.99) days vs (10.01±8.79) days, P=0.368. The death group and survival group had no significant difference.Conclusions:(1)Compared with the survival group,the patients of death group had older age, severe underlying diseases, internal diseases, immunocompromised and the high incidence of infectious shock,AKI, heart failure and other organ dysfunction. These factors showed a significant correlation with the poor prognosis of ARDS patients.(2) Compared with the survival group, pulmonary ARDS.the patients of the death group had high peak airway pressure, low oxygenation index. The death group and survival group had significant difference at PCO2 and muscle relaxants,but had no significant difference at the incidence of pneumothorax complications of mechanical ventilation. The muscle relaxant can be applied to improve respiratory system compliance of ARDS patients on the basis of mechanical ventilation strategy with low tidal volum.The optimal PEEP was select according to oxygenation index.The higher PEEP may be required to reduce pulmonary lung recruitment and promote lung recruitment for higher grade of the severity of ARDS. If necessary, respiratory rate can be increased to clear carbon dioxide retention.(3) The ARDS patients had higher pulmonary vascular permeability with more extravascular lung water. The ARDS patients had high mortality rate and worse prognosis with more severe grade,so EVLWI and PVPI had a good correlation with the prognosis of ARDS patients.To observe EVLWI and PVPI dynamically was in favor of fluid management with ARDS patients and to determine prognosis.(4) Due to the different prognosis, the total and ICU hospitalization time of survival group was significantly longer than the death group.The survival group could be given more non-mechanical ventilation time.The mechanical ventilation time of the two groups had no difference.