| Objective: ALI/ARDS (acute lung injury/acute respiratory distress syndrome) is the common diseases of critically ill patients in ICU (Intensive Care Unit), which with a high fatality rate. Permeability pulmonary edema was an important feature of the ALI/ARDS patients. Pulse indicator contious cadiac output (PICCO) technology can measured Pulmonary Vascular Permeability Index (PVPI) and Extravascular Lung Water Index (EVLWI) which are to determine the type of pulmonary edema and evaluation indicators. Dynamic monitoring of EVIWI can be helped to identify pulmonary edema, and to beneficial for clinical prevention and treatment of pulmonary edema. There are pulmonary capillary endothelial cells and alveolar epithelial cells barrier permeability, alveolar and interstitial pulmonary edema in ALI/ARDS patients. The accumulation of a large number of fluid, which is rich in protein such as Neutrophil Elastase (NE) and with a variety of neutrophil-based inflammatory cells is also found. In addition, the alveolar epithelial cells and fibroblasts can produce much inflammatory cytokines cytokines such as Vascular Endothelial Growth Factor (VEGF), and thus exacerbate inflammatory reactions. NE and VEGF which has a potent pro-inflammatory role of systemic inflammatory response are considered to lead to lung epithelial and pulmonary capillary endothelial permeability and contribute to pulmonary edema. With the development of the pathogenesis of ARDS and the mechanism of Continuous Blood Purification (CBP), people began to treat ARDS with CBP in 20th century. High Volume Hemofiltration (HVHF) is considered to increase the replacement fluid input and to improve the large and medium sized solutes removal. In this study, 15 patients with ALI/ARDS, were choosed before and after treatment with HVHF. PICCO technique was used to observe state of oxygen and the changes of EVLWI., while the changes of NE and VEGF were also detected before and after treatment with HVHF. The purpose of this study was to explore the role of plasma NE and VEGF in the pathophysiology of ALI/ARDS, the effects of extravascular lung water after treatment with HVHF.Methods:Fifteen patients,which were diagnosed as ALI/ARDS according to American-European Consensus Conference (AECC) criteria in 1994, were selected in this study. All the patients treated with HVHF and apply the PiCCO monitor (single-instruction agent through the lung-heat dilution technique). Records were enrolled at the following time points: pre-HVHF (T0) and after treatment with HVHF 24h (T1), 48h (T2), 72h (T3). The parameters included extravascular lung water index (EVLWI), pulmonary vascular permeability permeability index (PVPI), Oxygenation ratio (PaO2/FiO2 ratio), Intra-thoracic Blood Volume Index (ITBVI) ,central venous pressure (CVP), acute lung injury score (LIS) and acute physiology and chronic Health (APACHEâ…¡) score. At the same time, venous blood samples were measured in plasma neutrophil elastase (NE) and vascular endothelial growth factor (VEGF) by enzyme linked immunosorbent assay (ELISA). According to the prognosis, the patients were divided into the survival group and death group. Twenty healthy volunteers were as a control for VEGF and NE levels.Results:1 The hemodynamic indexes and PaO2/FiO2 changes after HVHF treatment:In 15 patients, compared with T3 and T0 point, CVP changes in pre-HVHF and pro-HVHF, were statistically significant difference (P<0.05). As for ITBVI, there were no statistically significant differences among all time points. EVLEI had downward trend, and T2 and T3 compared with T0 point were statistically significant difference (P<0.05). For PVPI, there are significant differences betewen T2 and T0 point (P<0.01). So did in T3 compared with T0 point (P<0.05). PaO2/FiO2 were increased, and T1, T2 compared with T0 time point were statistically significant difference (P<0.05), but the difference of T3 compared with T0 was significantly (P<0.01).2 The APACHEâ…¡score, LIS score changes before and after HVHF treatment :APACHEâ…¡score after treatment HVHF gradually reduced, with statistical significance (P<0.05). LIS score was also trend lower, with statistically significant (P<0.05 or P<0.01).3 The comparison between ALI / ARDS patients and healthy volunteers: Compared with the healthy volunteers, the plasma NE, and VEGF in ALI /ARDS patients were significantly higher before HVHF treatment (P<0.01).4 The VEGF and NE levels before and after HVHF treatment : After HVHF treatment, the NE and VEGF levels of all patients were significantly lower. Compared with the T0 point, each time point differences were statistically significant (P<0.05 or P<0.01). In survival group, the VEGF and NE levels showed a downward trend. Compared with T3 and T0 time Points, the difference was statistically significant (P<0.05). Compared with T0 point, The VEGF levels after HVHF treatment time point in T3 had significantly statistically difference (P<0.01). In death cases, treated within 48 hours, the NE, and VEGF had statistically significant difference (P<0.05), but there was no statistical difference after 72 hours. Ultrafiltrate were detected in both the NE and VEGF.Conclusion:1 For all the ALI/ARDS patients after HVHF treatment, pulmonary vascular permeability were reduced, and extravascular lung water decreased, and oxygen were improved.2 For all the ALI/ARDS patients, neutrophil elastase and vascular endothelial growth factor levels were significantly higher compared with healthy people, and continuing high levels of NE and VEGF had poor prognosis.3 HVHF treatment had the effects of clearing part of the NE and VEGF, reducing their concentrations, reducing inflammation and improving blood vessel permeability, and reducing extravascular lung water, and then reducing pulmonary edema, thereby improving the oxygen and status.4 HVHF treatment can reduce the mortality of ALI/ARDS patients, improve the prognosis, which may be a useful treatment for ALI/ARDS. |
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