Search

Aiming at a kind of dual-rate Hammerstein system, based on the auxiliary model identification idea, using the maximum likelihood principle and recursive identification technology, this paper proposes a maximum likelihood recursive least squares algorithm. The main method is to construct an auxiliary model for the unknown output in the model, and use the output of the auxiliary model to predict the unknown output. This method can directly identify parameters based on the dual-rate input and output data. The simulation experiments show that the proposed algorithm can effectively identify the dual-rate Hammerstein system, and the final error tends to be about 1%.

Objective: Neurogenic pulmonary edema (NPE ) was indicative of poor prognosis in the epidemic of enterovirus 71 infections. The pathogenesis of NPE remains poorly understood. The objectives of this experimental study were to explore whether RAS is activated during NPE in rabbit models induced by fibrin and the effects of an angiotensin converting enzyme inhibitor (enalaprilat) on NPE., Method: NPE models were induced by intracisternal injection of fibrinogen and thrombin. According to random number table method, 18 healthy adult New Zealand rabbits were assigned to three groups (with 6 in each) : normal control group (Con group), NPE group and enalaprilat treated (Ena) group. After establishment of NPE models, rabbits in Ena group were given intravenous enalaprilat 0.5 mg/kg. Expression of ACE,ACE2,AT1R mRNA of the lung tissue were evaluated by real-time polymerise chain reaction; and Ang II of the lung tissue was determined by enzyme linked immunosorbent assay ( ELISA ). Meanwhile, histopathological lung injury scores were evaluated., Result: ACE mRNA expression level in NPE group ( 17.2 ± 3.3) appeared an increasing trend in contrast to Con group ( 12.6 ± 5.2 ) and Ena group ( 11.5 ± 2.4, both P > 0.05 ). Compared with Con group (81 ± 22 ), ACE2 mRNA expression levels of NPE group ( 52 ± 6 ) and Ena group ( 45 ± 13 ) both decreased ( both P < 0.05 ) . ACE mRNA/ACE2 mRNA expression levels of NPE group ( 0.33 ± 0.06 ) and Ena group ( 0.26 ± 0.04 ) were higher than those of Con group ( 0.16 ± 0.05, both P < 0.05 ), as well as the ratio of Ena group decreased compared with untreated NPE group ( 0.26 ± 0.04 vs. 0.33 ± 0.06, P < 0.05 ) . There were no statistically significant differences in expression of AT1 mRNA of the lung tissue among three groups, but Ena group ( 4.8 ± 1.1) in contrast to NPE group ( 6.7 ± 1.3) has no significant difference (P > 0.05). Lung AngII level of NPE group [(540 ± 147) pg/ml] was significantly higher than that of Con group [(253 ± 37 ) pg/ml] and Ena group [(309 ± 35 ) pg/ml, both P < 0.05 ]. Gross pathologic examination showed that pink foamy edema fluid appeared in the tracheal tubes in NPE group, but spontaneously appeared in neither Con group nor Ena group; and the level of pulmonary subpleural bleeding in Con group, 12 graded 0; in NPE group, 2 graded II, 10 graded III; in Ena group, 2 graded, 8 grade II, 2 grade III. The histopathologic lung injury scores in Ena group was decreased in contrast to NPE group (1.36 ± 0.26 vs.2.32 ± 0.49, P < 0.05) and mainly for the improvement of alveolar overdistension and interstitial edema., Conclusion: The present study showed that when NPE occurs, a high lung AngII concentration was associated with an imbalance between ACE mRNA to ACE2 mRNA expression level. Activated local RAS in lung tissue resulted in lung injury. Enalaprilat treatment may attenuate lung injury by interventing local RAS in lung tissue with decreased ratio of ACE mRNA to ACE2 mRNA and lung AngII concentration. The result will be significant for the angiotensin converting enzyme inhibitor used in the theatment of NPE.

Objective: To evaluate efficacy of continuous blood purification (CBP) in childhood severe sepsis through the analysis of organ function, inflammatory mediators and prognosis., Method: Forty-seven children with severe sepsis aged 29 days -16 years who were treated in PICU of Shanghai and Zhejiang five hospitals during October 1, 2011 and September 30, 2012 were enrolled; 30 cases treated with CBP were recorded as logged group , 17 cases without CBP as unlogged group. Changes in the cardiovascular, respiratory function, renal function, inflammatory markers, PRISM score III, PCIS and survival were observed and compared between the two groups at baseline (d0), first days (d1), second days (d2), third days (d3), fifth days (d5)., Result: (1) Cardiovascular function: In d3 and d5, heart rate (HR) and mean arterial pressure (MAP) were improved as compared to unlogged group (121, 119 vs. 138, 137; 71, 80 mmHg vs. 63, 62 mmHg, P < 0.05), with no statistical significance in arterial blood lactate concentration. (2) Oxygenation index (PaO₂/FiO₂) and arterial oxygen saturation (SaO₂) increased as compared to unlogged group, but did not reach statistical significance. (3) Blood urea nitrogen (BUN) and creatinine (Cr) were improved as compared with unlogged group from d1 (P < 0.05). (4) Inflammatory mediators did not show significant differences. (5) Twenty-eight days survival rate: logged group was 70.0%, unlogged group was 52.9%, but the difference was not statistically significant (P = 0.242)., Conclusion: CBP can improve circulatory function, oxygenation, and renal function in children with severe sepsis. No evidence was found that CBP could decrease the level of inflammatory mediators, improve critical score and 28 days survival rate.

Objective: To learn application status of continuous blood purification (CBP) in pediatric intensive care unit (PICU), to provide reference to promote the development of CBP technology., Method: The survey of CBP application was conducted using questionnaire in 40 hospitals providing intensive care, which included children's hospitals and the pediatric sections of general hospitals from 28 provinces/municipalities/autonomous regions in China during March to July of 2012., Result: Totally 38 hospital replied, 25 hospitals carried out CBP technology, first carried out in 1997, the median year was 2008, 21 hospitals' PICU could independently carry out CBP device, 18 hospitals had the nurses who could professionally operate, routinely maintain the device. Continuous veno-venous hemodiafiltration was the largest implementation mode of CBP, accounting for 51.9%. Twenty-three hospitals used ordinary heparin, and 2 hospitals used low molecular weight heparin; 21 hospitals chose activated partial thromboplastin time as the coagulation testing, due to lack of equipment, only four hospitals chose activated clotting time as coagulation testing. Only 3 hospitals could apply before and after dilution joint technology. Kidney failure is still the disease accounting for the highest proportion of diseases requiring CBP application, accounting for 38.1%, followed by sepsis, 19.1%, drug poisoning 16.7%., Conclusion: CBP started 10 years ago, and got attention and promotion nearly five years ago in China, but the associated personnel, equipment were inadequate, anticoagulation, before and after dilution and other technical applications were not complete enough, high volume hemofiltration mode was seldom used.

Objective: To study the effect of thrombelastography (TEM) in the diagnosis of disseminated intravascular coagulation (DIC) in children., Method: The data of 117 children suffering from DIC in the pediatric intensive care unit (PICU) and Cardiologic ICU (CICU) in the authors' hospital from January 2010 to June 2012 were collected. Ninety-four children without DIC were enrolled into the control group. The platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimers and TEM were determined. The sensitivity and specificity of TEM were measured and the relevance of TEM and DIC was investigated to evaluate the effect of TEM and the conventional tests of the coagulation system in the diagnosis of DIC in children., Result: The average R reaction time in the DIC group was significantly longer than that in the control group[(13.3 ± 3.3)s vs. (4.5 ± 2.6)s, P = 0.000 5], and the average α-angle in the DIC group was smaller than that in the control group significantly (37.2° ± 1.4° vs. 55.6° ± 3.8°, P = 0.001 0). There was significant decrease in the maximal amplitude (MA) and amplitude (A) in the DIC group, compared with the control group. The OR value (95%CI) of the R reaction time,α-angle and MA was 3.538 (1.298-5.389), 2.472 (1.820-2.224) and 0.256 (0.263-0.831) respectively, which suggests good correlation with the existence of DIC (all P < 0.01). The specificity of R reaction time, α-angle and MA was higher than that of PT, APTT and D-dimers (85.7%, 73.5% and 72.9% vs. 27.0%, 42.1% and 68.2%) . The average R reaction time of children suffering from hemorrhage of severe liver disease(n = 36) was significantly longer than that of 40 healthy children [(9.2 ± 2.7) vs. (2.3 ± 1.8)s, P = 0.001 0], while the α-angle (42.8° ± 7.6° vs. 59.2° ± 10.8°, P = 0.040 0) and the MA value [(33.9 ± 5.1) vs.(56.0 ± 8.1) mm, P = 0.020 0] were significantly smaller. The average R reaction time of children suffering from congenital coagulopathy was significantly longer than that of healthy children [(6.8 ± 3.1) vs. (2.3 ± 1.8)s, P = 0.003 0], too., Conclusion: TEM, which has high specificity, is beneficial to the diagnosis of DIC in children.