Wolbachia affects reproduction in the spider mite Tetranychus truncatus (Acari: Tetranychidae) by regulating chorion protein S38-like and Rop.

Wolbachia-induced reproductive regulation in hosts has been used to control pest populations, but little is known about the molecular mechanism underlying Wolbachia regulation of host genes. Here, reproductive regulation by Wolbachia in the spider mite Tetranychus truncatus was studied at the molecular level. Infection with Wolbachia resulted in decreasing oviposition and cytoplasmic incompatibility in T. truncatus. Further RNA-seq revealed genes regulated by Wolbachia in T. truncatus. Real-time quantitative polymerase chain reaction (qPCR) showed that genes, including chorion protein S38-like and Rop were down-regulated by Wolbachia. RNA interference (RNAi) of chorion protein S38-like and Rop in Wolbachia-uninfected T. truncatus decreased oviposition, which was consistent with Wolbachia-induced oviposition decrease. Interestingly, suppressing Rop in Wolbachia-infected T. truncatus led to increased Wolbachia titres in eggs; however, this did not occur after RNAi of chorion protein S38-like. This is the first study to show that chorion protein S38-like and Rop facilitate Wolbachia-mediated changes in T. truncatus fertility. In addition, RNAi of Rop turned the body colour of Wolbachia-uninfected T. truncatus black, which indicates that the role of Rop is not limited to the reproductive regulation of T. truncatus.

The potential pigmentation-related genes in spider mites revealed by comparative transcriptomes of the red form of Tetranychus urticae.

Colouration in spider mites is due to the presence of carotenoids with diverse colours, including yellows, oranges and reds. Tetranychus urticae has two main colour forms, red and green. Although a ketolase has been implicated in determining the colour, the underlying genetic basis of body colour divergence between the two forms has remained unclear. Based on a combination of comparative transcriptomes and RNA interference, we found that a gene encoding a cytochrome P450 enzyme of the CYP4 clan (CYP389B1) had remarkably high expression in adult females of the red T. urticae, as well as in hybrids obtained by crossing the red and green forms. Down-regulation of this gene by RNA interference resulted in decreased accumulation of red pigment. Up-regulation of the expressions of a scavenger receptor gene (SCARB1) and a mitochondrial glycine transporter (SLC25A38) also strongly contributed to red colour development in adult females. Suppressing the mRNA levels of these genes also resulted in reduced accumulation of red pigment in the three other spider mites with red body colour. Our results provide evidence that the body colour divergence between the two forms is caused by different expressions of pigmentation-related genes, and point to a possible role of a novel cytochrome P450 gene (CYP389B1) in regulating red-orange body colour. These findings expand the number of candidate cytochrome P450 genes involved in endogenous pigmentation and will help to understand their roles in determining colour patterns in mites and other species.

Transcriptome of Tetranychus urticae embryos reveals insights into Wolbachia-induced cytoplasmic incompatibility.

The endosymbiont Wolbachia is known for manipulating host reproduction in selfish ways. However, the molecular mechanisms have not yet been investigated in embryos. Here, we found that Wolbachia had no effect on the number of deposited eggs in Tetranychus urticae Koch (Acari: Tetranychidae) but caused two types of reproductive manipulation: killing uninfected female embryos via cytoplasmic incompatibility (CI) and increasing the hatching ratio of infected female embryos. RNA sequencing analyses showed that 145 genes were differentially expressed between Wolbachia-infected (WI) and Wolbachia-uninfected (WU) embryos. Wolbachia infection down-regulated messenger RNA (mRNA) expression of glutathione S-transferase that could buffer oxidative stress. In addition, 1613 and 294 genes were identified as CI-specific up-/down-regulated genes. Compared to WU and WI embryos, embryos of CI cross strongly expressed genes involved in transcription, translation, tissue morphogenesis, DNA damage and mRNA surveillance. In contrast, most of the genes associated with energy production and metabolism were down-regulated in the CI embryos compared to the WU and WI embryos, which provides some clues as to the cause of death of CI embryos. These results identify several genes that could be candidates for explaining Wolbachia-induced CI. Our data form a basis to help elucidate the molecular consequences of CI in embryos.

Molecular characterizations of DNA methyltransferase 3 and its roles in temperature tolerance in the whitefly, Bemisia tabaci Mediterranean.

The Bemisia tabaci Mediterranean (MED) cryptic species is an invasive pest, distributed worldwide, with high ecological adaptability and thermotolerance. DNA methylation (a reversible chromatin modification) is one possible change that may occur within an organism subjected to environmental stress. To assess the effects of temperature stress on DNA methyltransferase 3 (Dnmt3) in MED, we cloned and sequenced BtDnmt3 and identified its functions in response to high and low temperatures. The full-length cDNA of BtDnmt3 was 3913 bp, with an open reading frame of 1962 bp, encoding a 73.89 kDa protein. In situ hybridization showed that BtDnmt3 was expressed mainly in the posterior region. BtDnmt3 messenger RNA expression levels were significantly down-regulated after exposure to heat shock and significantly up-regulated after exposure to cold shock. Furthermore, after feeding on double-stranded RNA specific for BtDnmt3, both heat resistance and cold resistance were significantly decreased, suggesting that BtDnmt3 is associated with thermal stress response and indicating a differential response to high- and low-temperature stress in MED. Together, these results highlight a potential role for DNA methylation in thermal resistance, which is a process important to successful invasion and colonization of an alien species in various environments.

Wolbachia-induced apoptosis associated with increased fecundity in Laodelphax striatellus (Hemiptera: Delphacidae).

Wolbachia influence the fitness of their invertebrate hosts. They have effects on reproductive incompatibility and egg production. Although the former are well characterized, the mechanistic basis of the latter is unclear. Here, we investigate whether apoptosis, which has been implicated in fecundity in model insects, influences the interaction between fecundity and Wolbachia in the planthopper Laodelphax striatellus. Wolbachia-infected females produced about 30% more eggs than uninfected females. We used the terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling staining to visualize apoptosis. Microscopic observations indicated that the Wolbachia strain wStri increased the number of ovarioles that contained apoptotic nurse cells in both young and aged adult females. The frequency of apoptosis was much higher in the infected females. The increased fecundity appeared to be a result of apoptosis of nurse cells, which provide nutrients to the growing oocytes. In addition, cell apoptosis inhibition by caspase messenger RNA interference in Wolbachia-infected L. striatellus markedly decreased egg numbers. Together, these data suggest that wStri might enhance fecundity by increasing the number of apoptotic cells in the ovaries in a caspase-dependent manner. Our findings establish a link between Wolbachia-induced apoptosis and egg production effects mediated by Wolbachia, although the way in which the endosymbiont influences caspase levels remains to be determined.

Evolutionary divergence of mitochondrial genomes in two Tetranychus species distributed across different climates.

There is increasing evidence that mitochondrial genomes (mitogenomes) can be under selection, whereas the selective regimes shaping mitogenome evolution remain largely unclear. To test for mitogenome evolution in relation to the climate adaptation, we explored mtDNA variation in two spider mite (Tetranychus) species that distribute across different climates. We sequenced 26 complete mitogenomes of Tetranychus truncates, which occurs in both warm and cold regions, and nine complete mitogenomes of Tetranychus pueraricola, which is restricted to warm regions. Patterns of evolution in the two species' mitogenomes were compared through a series of dN /dS methods and physicochemical profiles of amino acid replacements. We found that: (1) the mitogenomes of both species were under widespread purifying selection; (2) elevated directional adaptive selection was observed in the T. truncatus mitogenome, perhaps linked to the cold climates adaptation of T. truncatus; and (3) the strength of selection varied across genes, and diversifying positive selection detected on ND4 and ATP6 pointed to their crucial roles during adaptation to different climatic conditions. This study gained insight into the mitogenome evolution in relation to the climate adaptation.

New microsatellites revealed strong gene flow among populations of a new outbreak pest, Athetis lepigone (Möschler).

Athetis lepigone (Möschler) (Lepidoptera: Noctuidae) is a new outbreak pest in China. Consequently, it is unclear whether the emergence and spread of the outbreak of this pest are triggered by rapid in situ population size increases in each outbreak area, or by immigrants from a potential source area in China. In order to explore the outbreak process of this pest through a population genetics approach, we developed ten novel polymorphic expressed sequence tags (EST)-derived microsatellites. These new microsatellites had moderately high levels of polymorphism in the tested population. The number of alleles per locus ranged from 3 to 19, with an average of 8.6, and the expected heterozygosity ranged from 0.269 to 0.783. A preliminary population genetic analysis using these new microsatellites revealed a lack of population genetic structure in natural populations of A. lepigone. The estimates of recent migration rate revealed strong gene flow among populations. In conclusion, our study developed the first set of EST-microsatellite markers and shed a new light on the population genetic structure of this pest in China.

Identifying the germ cells during embryogenesis and gametogenesis by germ-line gene vasa in an anadromous fish, American shad Alosa sapidissima.

American shad Alosa sapidissima, an anadromous clupeid, exhibits variation in reproductive strategies, including semelparity and iteroparity. It provides an excellent model for studying the behaviour of germ cells in anadromous fish during their migration from sea to river. The vasa gene was characterized in A. sapidissima as a germ-cell marker to elaborate the process of germ-cell development and differentiation in anadromous species. A complementary (c)DNA fragment of 819 bp, partial open reading frame (ORF), was cloned by degenerate PCR and named as ASvas. In adult A. sapidissima, vasa transcript was exclusively detected in gonads by reverse-transcription (RT)-PCR. Through chromogenic in situ hybridization, the vasa messenger (m)RNA was specifically detected in primordial germ cells (PGC) in embryos and germ cells at early stages in ovary and testis. Besides, the cellular distribution profile of Vasa protein also proved that vasa gene could be used as a germ-line marker to trace the PGCs migration during embryogenesis and the germ-cell differentiation during gametogenesis in A. sapidissima. During embryogenesis, the migrating PGCs were clearly detected at tail-bud stage and the PGCs reached the genital ridge at the stage of pre-hatching stage in A. sapidissima embryos. During gametogenesis, the Vasa protein was dynamically expressed in differentiating germ cells at different stages in adult gonads. As far as we know, this is the first report to demonstrate the PGCs migration and germ-cell differentiation through vasa gene expression in the anadromous species. The findings will pave a way for investigating germ-cell development and maturation in the A. sapidissima and other anadromous fish.

[The application of extracorporeal membrane oxygenation in children in China].

Objective: To investigate the application of extracorporeal membrane oxygenation (ECMO) in pediatrics in China as well as the outcomes. Methods: Data was conducted by questionnaire to investigate the use of ECMO in children under the age of 18 in China by June 30, 2017. All patients were divided into two age groups: pediatric patients (29 d-18 y) and neonates (1-28 d); Also by the causes of ECMO treating including cardiac, respiratory and extracorporeal cardiopulmonary resuscitation (ECPR). The form included the numbers of ECMO cases, weaned and discharged cases, according to the different ages and causes. In addition, the departments that routinely participate in ECMO management were acquired. Results: Totally 43 tertiary hospitals were enrolled, of which 30 have implemented ECMO for the children patients (comprising pediatrics and neonates), including 14 general hospitals, 5 cardiothoracic specialty hospitals and 11 children's or women and children's hospitals. ECMO for pediatrics and neonates was firstly carried out at mainland China in 2004. To the deadline of investigation, 800 patients were supported with ECMO, among which 658 were pediatrics, much more than 142 of neonates. As to pediatrics, 453 were supported with ECMO for cardiac indications with 287 (63.4%) weaned off and 215 (47.5%) survived to discharge; for respiratory causes, 79 cases were registered with 47 (59.5%) weaned off and 36 (45.6%) discharged; for ECPR, 126 were enrolled with 62 (49.2%) successfully weaned off and 48 (38.1%) discharged. In contrast, neonatal patients undergoing cardiac ECMO contained 79 cases, with 39 (49.4%) weaned off and 26 (32.9%) discharged; due to respiratory causes, 40 neonates were included, with 26 (65.0%) weaned off and 21 (52.5%) discharged; 23 neonatal patients consisted of ECPR cause and 10 (43.5%) of them successfully weaned off, but only 6 (26.1%) finally survived. Among the 30 hospitals conducted ECMO for pediatrics and neonates, the average number of departments for ECMO management is 4.03±1.87. Conclusions: Although ECMO used for children in mainland China is relatively late, a certain number of cases have been accumulated, and there is still a gap compared with the international standard. Meanwhile, each hospital has preliminarily built up its own ECMO team.

Transcriptome and proteome analyses reveal complex mechanisms of reproductive diapause in the two-spotted spider mite, Tetranychus urticae.

Although a variety of factors underlying diapause have been identified in arthropods and other organisms, the molecular mechanisms regulating diapause are still largely unknown. Here, to better understand this process, we examined diapause-associated genes in the two-spotted spider mite, Tetranychus urticae, by comparing the transcriptomes and proteomes of early diapausing and reproductive adult females. Amongst genes underlying diapause revealed by the transcriptomic and proteomic data sets, we described the noticeable change in Ca2+ -associated genes, including 65 Ca2+ -binding protein genes and 23 Ca2+ transporter genes, indicating that Ca2+ signalling has a substantial role in diapause regulation. Other interesting changes in diapause included up-regulation of (1) glutamate receptors that may be involved in synaptic plasticity changes, (2) genes involved in cytoskeletal reorganization including genes encoding each of the components of thick and thin filaments, tubulin and members of integrin signalling and (3) genes involved in anaerobic energy metabolism, which reflects a shift to anaerobic energy metabolism in early diapausing mites.

Preoperative evaluation and surgical technique of functional and cosmetic aspects in zygomatic complex fracture patients.

The zygomatico-maxillary complex functions as the principle buttress of the face and is the cornerstone to an individual’s aesthetic appearance. Its fracture not only creates cosmetic deformities owing to its position and facial contour, but can also cause disruption of ocular and mandibular functions. The aim of this study was to evaluate the quality, efficacy and impact of internal fixation of zygomatic complex fractures on functional and cosmetic outcomes. A prospective study was carried out on 100 patients who were divided according to the classification and the severity of injury. Subjective evaluation was submitted based on the patient’s perception of signs and symptoms in the preoperative and postoperative periods. Intraoperative and postoperative assessment of bone reduction quality was made according to the type of the fracture and related difficulties; also, the difference between these groups was observed as functional and esthetic outcome. To optimize the treatment of zygomatic bone fractures, a pre-designed questionnaire was used for subjective evaluation of symptoms and treatment outcome. In 70% of cases, ophthalmologic consultation was taken and was most common in type VII fractures (100% cases). Neurosensory disturbance was the most common finding (60%), followed by diplopia (56R%), pain upon mouth opening (54%) and malar depression (50%). Out of all possible 400 fracture sites in 100 patients of zygomatic complex fractures, 266 (66.5%) fractures were detected by clinical examination, in contrast to 330 (82.5%) on radiological examination, which were highest at zygomatic-maxillary buttress (93%) followed by infraorbital rim (91%) and almost equal among fronto-zygomatic site (72%) and zygomatic arch (74%). The scores from the questionnaire for annoyance were significantly higher for paraesthesia (23%) than for trismus (10%), pain (8.5%), or deformity (8.25%). Residual deformity and pain significantly influenced the total satisfaction. Conclusively, there are many treatment modalities available for zygomatic complex fractures, and the preferred methods should be selected on the basis of fracture type, fracture severity, pre-operative signs and symptoms. Regarding the requirements of fracture site exposure and actual fixation, one priority should be to minimize postoperative complications, morbidity and residual deformities.

Femoral nerve repair using an h-type nerve regeneration chamber in rats.

Peripheral nerve injury in surgical trauma patients is very common. The femoral nerve can be divided into two branches: one regarding the quadricep muscles and one the skin. After nerve transection and suture, the motor axons have an equal opportunity to regenerate into the original muscle branch, or regenerate into the sensory skin nerves. These anatomical features of femoral nerve have made it important in nerve regeneration research. Thus, this study was designed to examine the effects of an H-type nerve regeneration chamber on motor nerve regeneration after femoral nerve injury. We performed femoral nerve injuries in adult rats and assessed nerve recovery over a 4-week post-operative period. Additionally, we evaluated nerve regeneration in the same animals anatomically, using several histological staining methods to provide structure analyses. We found that H-type nerve regeneration chamber provided enhanced improvement in nerve regeneration without nerve anastomosis, as compared with nerve anastomosis. Furthermore, incorrect nerve anastomosis reduced the nerve fiber diameter and thickness of myelin sheaths in regenerated nerve fibers. Finally, H-type nerve regeneration chamber provided enhanced functional recovery of nerve fibers, particularly for motor nerves. Together, our results suggest that direct nerve suture cannot effectively improve the functional recovery of damaged nerves, and nerve chemotaxis coupled with nerve regeneration chamber can effectively improve the effects of nerve regeneration, and enhance the prognosis of nerve injury repair.

Femoral nerve repair using an H-type nerve regeneration chamber in rats.

Peripheral nerve injury in surgical trauma patients is very common. The femoral nerve can be divided into two branches: one regarding the quadricep muscles, and one the skin. After nerve transection and suture, the motor axons have an equal opportunity to regenerate into the original muscle branch, or regenerate into the sensory skin nerves. These anatomical features of femoral nerve have made it important in nerve regeneration research. Thus, this study was designed to examine the effects of an H-type nerve regeneration chamber on motor nerve regeneration after femoral nerve injury. We performed femoral nerve injuries in adult rats and assessed nerve recovery over a 4-week post-operative period. Additionally, we evaluated nerve regeneration in the same animals anatomically, using several histological staining methods to provide structure analyses. We found that H-type nerve regeneration chamber provided enhanced improvement in nerve regeneration without nerve anastomosis, as compared with nerve anastomosis. Furthermore, incorrect nerve anastomosis reduced the nerve fiber diameter and thickness of myelin sheaths in regenerated nerve fibers. Finally, H-type nerve regeneration chamber provided enhanced functional recovery of nerve fibers, particularly for motor nerves. Together, our results suggest that direct nerve suture cannot effectively improve the functional recovery of damaged nerves, and nerve chemotaxis coupled with nerve regeneration chamber can effectively improve the effects of nerve regeneration, and enhance the prognosis of nerve injury repair.

Geography has a greater effect than Wolbachia infection on population genetic structure in the spider mite, Tetranychus pueraricola.

Wolbachia is an intracellular symbiotic bacterium that infects various spider mite species and is associated with alterations in host reproduction, which indicates the potential role in mite evolution. However, studies of Wolbachia infections in the spider mite Tetranychus pueraricola, a major agricultural pest, are limited. Here, we used multilocus sequence typing to determine Wolbachia infection status and examined the relationship between Wolbachia infection status and mitochondrial diversity in T. pueraricola from 12 populations in China. The prevalence of Wolbachia ranged from 2.8 to 50%, and three strains (wTpue1, wTpue2, and wTpue3) were identified. We also found double infections (wTpue1 + wTpue3) within the same individuals. Furthermore, the wTpue1 strain caused weak cytoplasmic incompatibility (CI) (egg hatchability ~55%), whereas another widespread strain, wTpue3, did not induce CI. There was no reduction in mitochondrial DNA (mtDNA) or nuclear DNA diversity among infected individuals, and mtDNA haplotypes did not correspond to specific Wolbachia strains. Phylogenetic analysis and analysis of molecular variance revealed that the distribution of mtDNA and nuclear DNA haplotypes were significantly associated with geography. These findings indicate that Wolbachia infection in T. pueraricola is complex, but T. pueraricola genetic differentiation likely resulted from substantial geographic isolation.

Short Communication Development of microsatellite markers and genetic diversity analysis for Pelodiscus sinensis.

Pelodiscus sinensis is a common freshwater soft-shell turtle found in China, and is an important aquaculture species. In this study, 20 polymorphic microsatellite primers were developed from the transcriptome. The genetic diversity of three populations of P. sinensis was evaluated, using 72 individuals. The number of alleles per locus ranged from 3 to 26. The observed and expected heterozygosities varied from 0.208 to 0.958, and from 0.302 to 0.963, respectively. The polymorphic information content varied from 0.283 to 0.953. No significant linkage disequilibrium was detected. These markers will be useful for future population genetic studies and molecular breeding of P. sinensis.

How do hosts react to endosymbionts? A new insight into the molecular mechanisms underlying the Wolbachia-host association.

Wolbachia is an intracellular bacterium that has aroused intense interest because of its ability to alter the biology of its host in diverse ways. In the two-spotted spider mite, Tetranychus urticae, Wolbachia can induce complex cytoplasmic incompatibility (CI) phenotypes and fitness changes, although little is known about the mechanisms. In the present study, we selected a strain of T. urticae, in which Wolbachia infection was associated with strong CI and enhanced female fecundity, to investigate changes in the transcriptome of T. urticae in Wolbachia-infected vs. uninfected lines. The responses were found to be sex-specific, with the transcription of 251 genes being affected in females and 171 genes being affected in males. Some of the more profoundly affected genes in both sexes were lipocalin genes and genes involved in oxidation reduction, digestion and detoxification. Several of the differentially expressed genes have potential roles in reproduction. Interestingly, unlike certain Wolbachia transinfections in novel hosts, the Wolbachia-host association in the present study showed no clear evidence of host immune priming by Wolbachia, although a few potential immune genes were affected.

Sex-dependent activity of de novo methyltransferase 3 (Tudnmt3) in the two-spotted mite, Tetranychus urticae†Koch.

DNA methylation is an epigenetic mechanism for regulating developmental and other important processes in eukaryotes. Several components of the DNA methylation machinery have been identified, such as DNA methyltransferases. However, little is known about DNA methyltransferases in chelicerates, which is the second largest arthropod group. Epigenetics are expected to have a crucial role in the metabolism and development of this group. Here, we investigated the role of DNA methyltransferase 3 in the development of Tetranychus urticae Koch. In silico analyses clearly showed that this enzyme possesses the necessary conserved motifs for the catalytic activity of de novo methylation of DNA. Real-time PCR revealed that T. urticae de novo methyltransferase 3 (Tudnmt3) is expressed ubiquitously and throughout the life cycle of the two-spotted spider mite. However, the pattern of Tudnmt3 expression was sex-dependent during the adult stage. Whole in situ hybridization provided supportive evidence that Tudnmt3 is linked to the differentiation of the gonads in adult females and males. Methylation-sensitive amplification polymorphism analyses of 119 loci showed that the status of DNA methylation is partially different between adult females and males, raising the possibility that this sex-dependent DNA methylation pattern is mediated by different methylation activity of Tudnmt3.

Development of microsatellite markers for, and a preliminary population genetic analysis of, the white-backed planthopper.

For a better understanding of the population structure and dispersal rates of Sogatella furcifera, we developed 21 novel polymorphic expressed sequence tags (EST) derived microsatellites, which were successfully amplified in four multiplex polymerase chain reaction sets. These new microsatellites were firstly assessed in 20 individuals sampled from Wenshan in China. The results showed that all 21 loci were highly polymorphic; the number of alleles ranged from 3 to 9, with an average of 4.8 alleles per locus. The observed and expected heterozygosity ranged from 0.200 to 0.900 and from 0.184 to 0.799, respectively. Nineteen of the 21 microsatellites without null allele, were subsequently used for population genetic structure analyses of five S. furcifera populations sampled in south region of China (sites up to 1314 kilometers apart). The observed and expected heterozygosity for each population ranged from 0.436 to 0.494 and from 0.454 to 0.482, respectively. The level of population differentiation was very low, with an average pairwise F ST of 0.002. Bayesian cluster analysis result suggested that the five S. furcifera populations formed one genetic cluster. Discriminant analysis of principle components detected three genetic clusters. The spread of the three clusters across the five populations explained the lack of population differentiation and the Bayesian cluster result. All the results indicated that long-distance migration of this pest allowed genetic mixing between populations from remote geographical origins. These new microsatellites will be powerful tools for population genetics studies of S. furcifera.

[Prognostic factors of extracorporeal membrane oxygenation in the treatment of severe pediatric acute respiratory distress syndrome].

Objective: To explore the factors affecting the prognosis of severe pediatric acute respiratory distress syndrome (ARDS) after receiving extracorporeal membrane oxygenation (ECMO) support. Methods: It was a multicenter prospective observational study. A total of 95 children with severe ARDS who were treated with ECMO salvage therapy from January 2018 to December 2022 in 9 pediatric ECMO centers in China were enrolled in the study. The general data, disease severity, organ function, comprehensive treatment and prognosis were recorded, and they were divided into survival group and death group according to the outcome at discharge. T test, chi-square test, multivariate Logistic regression and mixed linear model were used to analyze the relationship among baseline before ECMO treatment, some important indicators (pediatric critical scores, platelet count, albumin, fibrinogen, etc) during ECMO treatment and prognosis. Results: Among the 95 children with severe ARDS who received ECMO, 55 (58%) were males and 40 (42%) were females, aged 36.9 (0.5, 72.0) months. Twelve children (13%) were immunodeficient. Sixty-eight (72%) children were treated with venous artery (VA) mode and 27 (28%) with venous vein (VV) mode. The discharge survival rates of overall, VA, and VV mode children were 51% (48/95), 47% (32/68), and 59% (16/27), respectively. The number of immunodeficient children in the death group was higher, and there were lower pediatric critical scores, platelet count, albumin, fibrinogen and arterial oxygen partial pressure/fraction of inspired oxygen (PaO2/FiO2), higher ventilator driving pressure (ΔP), oxygenaion index (OI), and longer ARDS duration before ECMO (all P<0.05). There were no statistically significant differences in other indicators, including age, gender, weight, and ECMO mode among different prognostic groups (all P>0.05). High ΔP, high OI, low P/F, and low albumin were high-risk factors affecting prognosis(all P<0.05). After further grouping, it was found that ΔP≥25 cmH2O (1 cmH2O=0.098 kPa), P/F≤67 mmHg (1 mmHg=0.133 kPa) and OI≥35 were the thresholds for predicting poor prognosis (P<0.05). From 24 h after ECMO, there were significant differences in ΔP, P/F and OI between the dead group and the survival group (all P<0.05), and the differences gradually increased with the ECMO process. The platelet level was significant from 7 days after ECMO (P<0.05) and gradually expanded. Blood lactate levels showed a significant difference between the 2 groups on before and after ECMO (P<0.05) and gradually increased from 24 h after ECMO. Conclusions: The risk factors affecting the prognosis of severe ARDS in ECMO include high ΔP, high OI, low P/F and low albumin purification therapy before ECMO. The gradual decrease of ΔP, OI and increase of P/F from 24 h of ECMO predicted a good prognosis, while the gradual increase of lactate after ECMO application showed a poor prognosis.

[Survey on the application of external cardiopulmonary resuscitation in Chinese children with sudden cardiac arrest].

Objectives: To investigate the current application status and implementation difficulties of extracorporeal cardiopulmonary resuscitation (ECPR) in children with sudden cardiac arrest. Methods: This cross-sectional survey was conducted in 35 hospitals. A Children's ECPR Information Questionnaire on the implementation status of ECPR technology (abbreviated as the questionnaire) was designed, to collect the data of 385 children treated with ECPR in the 35 hospitals. The survey extracted the information about development of ECPR, the maintenance of extracorporeal membrane oxygenation (ECMO) machine, the indication of ECPR, and the difficulties of implementation in China. These ECPR patients were grouped based on their age, the hospital location and level, to compare the survival rates after weaning and discharge. The statistical analysis used Chi-square test and one-way analysis of variance for the comparison between the groups, LSD method for post hoc testing, and Bonferroni method for pairwise comparison. Results: Of the 385 ECPR cases, 224 were males and 161 females. There were 185 (48.1%) survival cases after weaning and 157 (40.8%) after discharge. There were 324 children (84.2%) receiving ECPR for cardiac disease and 27 children (7.0%) for respiratory failure. The primary cause of death in ECPR patients was circulatory failure (82 cases, 35.9%), followed by brain failure (80 cases, 35.0%). The most common place of ECPR was intensive care unit (ICU) (278 cases, 72.2%); ECPR catheters were mostly inserted through incision (327 cases, 84.9%). There were 32 hospitals (91.4%) had established ECMO emergency teams, holding 125 ECMO machines in total. ECMO machines mainly located in ICU (89 pieces, 71.2%), and the majority of hospitals (32 units, 91.4%) did not have pre-charged loops. There were no statistically significant differences in the post-withdrawal and post-discharge survival rates of ECPR patients among different age groups, regions, and hospitals (all P>0.05). The top 5 difficulties in implementing ECPR in non-ICU environments were lack of ECMO machines (16 times), difficulty in placing CPR pipes (15 times), long time intervals between CPR and ECMO transfer (13 times), lack of conventional backup ECMO loops (10 times), and inability of ECMO emergency teams to quickly arrive at the site (5 times). Conclusion: ECPR has been gradually developed in the field of pediatric critical care in China, and needs to be further standardized. ECPR in non-ICU environment remains a challenge.