Accuracy of the spontaneous breathing trial using a combined CPAP + PSV model to predict extubation outcomes in very preterm infants.

BACKGROUND: Very preterm infants often require mechanical ventilation. However, objective criteria to predict the outcomes of extubation in very premature neonates remain lacking. The aim of this study was to investigate the accuracy of the spontaneous breathing trial (SBT) using a combined model of continuous positive airway pressure (CPAP) and low-level pressure support ventilation (PSV) to predict the extubation outcomes of preterm infants with gestational age < 32 weeks. METHODS: Preterm infants with gestational age < 32 weeks, birth weight < 1500 g and requiring mechanical ventilation were selected for the study. All infants underwent a 10-minute SBT using CPAP combined with low-level PSV prior to the planned extubation. Then, the infants were extubated within 1 h after SBT. The outcomes of extubation were considered successful if the neonates did not require reintubation 72 h after extubation. RESULTS: A total of 119 eligible preterm infants were enrolled in the study, with a median gestational age of 28.9 (27.1-30.3) weeks and a median birth weight of 1100 (900-1350) g. In total, 101 of all infants had successful extubation, 18 of whom failed and eventually had to be reintubated. Of the 102 infants who achieved SBT, 99 were successfully extubated, and 15 of the 17 infants who did not pass SBT had failed extubation. Finally, the diagnostic value for SBT could be assessed with a sensitivity of 98%, a specificity of 83.3%, a positive predictive value of 97.1% and a negative predictive value of 88.2%. CONCLUSION: SBT using a combined CPAP + low-level PSV model can predict the outcomes of extubation in very preterm infants with high sensitivity and specificity.

Anaerobic methane oxidation coupled to nitrite reduction can be a potential methane sink in coastal environments.

In the current study, we investigated nitrite-dependent anaerobic methane oxidation (N-DAMO) as a potential methane sink in the Hangzhou Bay and the adjacent Zhoushan sea area. The potential activity of the N-DAMO process was primarily observed in Hangzhou Bay by means of (13)C-labeling experiments, whereas very low or no potential N-DAMO activity could be detected in the Zhoushan sea area. The measured potential N-DAMO rates ranged from 0.2 to 1.3 nmol (13)CO2 g(-1) (dry sediment) day(-1), and the N-DAMO potentially contributed 2.0-9.4 % to the total microbial methane oxidation in the examined sediments. This indicated that the N-DAMO process may be an alternative pathway in the coastal methane cycle. Phylogenetic analyses confirmed the presence of Candidatus Methylomirabilis oxyfera-like bacteria in all the examined sediments, while the group A members (the dominant bacteria responsible for N-DAMO) were found mainly in Hangzhou Bay. Quantitative PCR showed that the 16S rRNA gene abundance of Candidatus M. oxyfera-like bacteria varied from 5.4 × 10(6) to 5.0 × 10(7) copies g(-1) (dry sediment), with a higher abundance observed in Hangzhou Bay. In addition, the overlying water NO3 (-) concentration and salinity were identified as the most important factors influencing the abundance and potential activity of Candidatus M. oxyfera-like bacteria in the examined sediments. This study showed the evidence of N-DAMO in coastal environments and indicated the importance of N-DAMO as a potential methane sink in coastal environments.

[Temporal and spatial distribution of red tide in Yangtze River Estuary and adjacent waters].

The events of red tide were collected in Yangtze River Estuary and adjacent waters from 1972 to 2009. Based on geographic information system (GIS) analysis on the temporal and spatial distribution of red tide, the distribution map was generated accordingly. The results show: (1) There are three red tide-prone areas, which are outside the Yangtze River estuary and the eastern of Sheshan, Huaniaoshan-Shengshan-Gouqi, Zhoushan and the eastern of Zhujiajian. The red tide occurred 174 times in total, in which there were 25 times covered the area was larger than 1 000 km2. After 2000, the frequency of red tide were significantly increasing; (2) The frequent occurrence of red tide was in May (51% of total occurrence) and June (20% of total occurrence); (3) In all of the red tide plankton, the dominant species were Prorocentrum danghaiense, Skeletonema costatum, Prorocentrum dantatum, Nactiluca scientillans. The red tides caused by these species were 38, 35, 15, 10 times separately.

[Phytoplankton distribution and variation in the Yangtze River Estuary and its adjacent sea].

Two cruises were carried out in the Yangtze River Estuary and its adjacent sea (29 degrees 30' - 32 degrees 00'N, west of 123 degrees E) in July (summer) and November (autumn), 2005. A total of 345 phytoplankton species, including 43 species causing red tide, were identified. Skeletonema costatum was the dominant species. The average cell abundance was lower in July (5.48 x 10(4) cells L(-1)) than in November (2.70 x 10(5) cells L-(-1)), but the average chlorophyll a concentration was higher in July (2.34 mg x m(-3)) than in November (1.32 mg x m(-3)). The average diversity index (H) was higher in July (1.51) than in November (0.86), as was average evenness (J) (0.59 and 0.34, respectively). Spatial distribution of phytoplankton featured distinct regionality, and the seasonal variation was controlled by factors such as water source, monsoon, nutrient, suspended matter, etc., and the diurnal variation mainly correlated with tide and stratification. At the same time, an evaluation of long-term monitoring data (1996 - 2005) showed that phytoplankton community structure had been changed. Long-term unbalance of N/P ratio caused dinoflagellates to increasingly dominate the phytoplankton population, and led to an increasing frequency of red tide caused by dinoflagellates. Controlling nutrient ratios is more important than just controlling terrigenous contamination input in improving sea area environmental status.