Objective To establish pulmonary acute lung injury(ALI)model in rats.Methods ALI model was induced in rats by intratracheal Escherichia coli injection[3 ml/kg,O111B4,(4.0～6.0)×1012 CFU/L].Mechanical ventilation was applied 12,24,36,48 and 72 h after Escherichia coli injection,PaO_2/FiO_2 and dynamic compliance were recorded,and the normal control group was also subjected to mechanical ventilation.After the experiment,lungs were fixed with formalin to perform pathological examination.Results At 12,24,36,48 and 72 h,the PaO_2/FiO_2 were(30.71±7.95)kPa,(21.66±5.34)kPa,(21.09±4.75)kPa,(25.01±8.78)kPa and(33.82±8.02)kPa,respectively,which were significantly lower than that in the normal control group(63.82±3.03)kPa(P＜0.01).At 12,24,36,48 and 72 h,the Cdyn were(4.23±0.13)ml/(kg·kPa),(4.19±0.96)ml/(kg·kPa),(4.28±0.69)ml/(kg·kPa),(4.44±0.62)ml/(kg·kPa)and(4.58±0.35)ml/(kg·kPa)respectively,which were significantly lower than that in the normal control group(8.16±0.78)mL/(kg·kPa)(P＜0.01).At 12,24,36,48 and 72,the percentage of ALI was 71.4%,100.0%,100.0%,83.3%and 57.1%respectively,and the percentage of ARDS was 28.6%,85.7%,83.3%,66.7%,14.3%respectively.As for pathological examinations,predominance of alveolar collapse,fibrinous exudates,alveolar wall edema and neutrophil recruitment into the alveolar space was observed.Hyaline membrane formation was found.At 72 h,inflammation was relieved.Conclusion We successfully established pulmonary ALI/ARDS model in rats induced by intratracheal Escherichia coli injection,and acquired some useful information by observing the lung function and morphological changes at different time points.

Objective To study the adrenal function in rats with pulmonary acute lung injury (ALI) induced by Escherichia coli (0111B4) . Methods ALI rat model was induced by intratracheal injection of E.coli (3 ml/kg,0111B4,(4.4-5.6) x 10~(12) CFU/L).ALI rats were then randomly divided into three groups,and each group had 10 rats.Mechanical ventilation was applied at three time points,6 hours,24 hours,and 36 hours after injection At each time point 8 rats were used as control with saline administered intratracheally.The plasma ACTH and corticosterone levels were measured after stimulated by 100 μg porcine ACTH.Results Compared with control group,the model group had a higher level of plasma ACTH at each time point (P < 0.01).The plasma ACTH level reached the peak at 24 hours.The model group had a higher level of plasma corticosterone at 6 hours (P < 0.01) and 24 hours (P <0.05),but had a lower level of plasma corticosterone at 36 hours (P < 0.05).The plasma corticosterone level reached the peak at 6 hours in model group,which was higher than 24 hours (P < 0.05).After stimulated by ACTH,the increased levels of corticosterone were lower in model group than those in control group (6 hours,P < 0.05; 24 hours and 36 hours,P < 0.01).Conclusions Adrenal dysfunction may occur at early stage of ALI in rats.With the disease developed,adrenal response to ACTH decreased.Low dose corticotrophin-stimulated test could evaluate adrenal function in rats with pulmonary ALI induced by Escherichia coli (O111B4).

Objective To determine the prevalence of mortality and respiratory support therapy evolved for severe respiratory failure in pediatric intensive care units(PICU)in China. Method Two sessions of prospective, multicentric, and descriptively epidemiological survey of acute respiratory distress syndrome(ARDS)was carried out in year 2004 and 2006,and survey of alveolar hypoventilation respiratory failure(AHRF)in 2006 by 20 PICUs in China. Data about severity, outcome and respiratory therapy of critically ill patients, as well as PICU facilities were documented prospectively. PICU facilities, patients' mortality and respiratory therapy in different years were compared. Mortality risk factors were analyzed by multivariate logistic regression. Results Compared with those data in year 2004,the number of PICU bed and ventilator increased in year 2006.But,there was no increase in area per bed in year 2006.Proportion of critically ill patients in 2006 was significantly higher than that in 2004(69.0%vs.57.5%,x2=318,P<0.01).There were no significant difference in mortalities of critically ill patients between these two years. According to multivariate regression analysis, mortality was lowered in PICU with increase in heavy working load of physicians, evidenced by linear trend test P=0.013.Mortality of ARDS in year 2006 was significantly lower than that in 2004(39.7%vs 55.8%,x2=6.59,P<0.01).Whereas there was no significant difference in ventilation mode,tidal volume and airway pressure level for ventilated patients between two years.Conclusions With increasing the capacity of PICU there was a significant improvement of treatment as reflected by outcome of ARDS.Mortality of PICU patients was inversely correlated to the working load done by physicians.