[Investigation on the current situation of the development of intensive care units in Inner Mongolia Autonomous Region in 2022].

OBJECTIVE: To investigate the development present situation of the department of critical care medicine in Inner Mongolia Autonomous Region (hereinafter referred to as Inner Mongolia), in order to promote the standardized and homogeneous development of critical care medicine in Inner Mongolia, and also provide a reference for discipline construction and resource allocation. METHODS: A survey study was conducted in comprehensive intensive care unit (ICU) of tertiary and secondary hospitals in Inner Mongolia by online questionnaire survey and telephone data verification. The questionnaire was based on the Guidelines for the Construction and Management of Intensive Care Units (Trial) (hereinafter referred to as the Guidelines) issued by the National Health Commission in 2009 and the development trend of the discipline. The questionnaire covered six aspects, including hospital basic information, ICU basic information, personnel allocation, medical quality management, technical skill and equipment configuration. The questionnaire was distributed in September 2022, and it was filled out by the discipline leaders or department heads of each hospital. RESULTS: As of October 24, 2022, a total of 101 questionnaires had been distributed, 85 questionnaires had been recovered, and the questionnaire recovery rate had reached 84.16%, of which 71 valid questionnaires had been collected in a total of 71 comprehensive ICU. (1) There were noticeable regional differences in the distribution of comprehensive ICU in Inner Mongolia, with a relatively weak distribution in the east and west, and the overall distribution was uneven. The development of critical care medicine in Inner Mongolia was still lacking. (2) Basic information of hospitals: the population and economy restricted the development of ICU. The average number of comprehensive ICU beds in the western region was only half of that in the central region (beds: 39.0 vs. 86.0), and the average number of ICU beds in the eastern region was in the middle (83.6 beds), which was relatively uneven. (3) Basic information of ICU: among the 71 comprehensive ICU surveyed, there were 44 tertiary hospitals and 27 secondary hospitals. The ratio of ICU beds to total beds in tertiary hospitals was significantly lower than that in secondary hospitals [(1.59±0.81)% vs. (2.11±1.07)%, P < 0.05], which were significantly lower than the requirements of the Guidelines of 2%-8%. The utilization rate of ICU in tertiary and secondary hospitals [(63.63±22.40)% and (44.65±20.66)%, P < 0.01] were both lower than the bed utilization rate required by the Guidelines (75% should be appropriate). (4) Staffing of ICU: there were 376 doctors and 1 117 nurses in tertiary hospitals, while secondary hospitals had 122 doctors and 331 nurses. There were significant differences in the composition ratio of the titles of doctors, the degree of doctors, and the titles of nurses between tertiary and secondary hospitals (all P < 0.05). Most of the doctors in tertiary hospitals had intermediate titles (attending physicians accounted for 41.49%), while most of the doctors in secondary hospitals had junior titles (resident physicians accounted for 43.44%). The education level of doctors in tertiary hospitals was generally higher than that in secondary hospitals (doctors: 2.13% vs. 0, masters: 37.24% vs. 8.20%). The proportion of nurses in tertiary hospitals was significantly lower than that in secondary hospitals (17.01% vs. 24.47%). The ratio of ICU doctors/ICU beds [(0.64±0.27)%, (0.59±0.34)%] and ICU nurses/ICU beds [(1.76±0.56)%, (1.51±0.48)%] in tertiary and secondary hospitals all failed to meet the requirements above 0.8 : 1 and 3 : 1 of the Guidelines. (5) Medical quality management of ICU: compared with secondary hospitals, the proportion of one-to-one drug-resistant bacteria care in tertiary hospitals (65.91% vs. 40.74%), multimodal analgesia and sedation (90.91% vs. 66.67%), and personal digital assistant (PDA) barcode scanning (43.18% vs. 14.81%) were significantly higher (all P < 0.05). (6) Technical skills of ICU: in terms of technical skills, the proportion of bronchoscopy, blood purification, jejunal nutrition tube placement and bedside ultrasound projects carried out in tertiary hospitals were higher than those in secondary hospitals (84.09% vs. 48.15%, 88.64% vs. 48.15%, 61.36% vs. 55.56%, 88.64% vs. 70.37%, all P < 0.05). Among them, the placement of jejunal nutrition tube, bedside ultrasound and extracorporeal membrane oxygenation were mainly completed independently in tertiary hospitals, while those in secondary hospitals tended to be completed in cooperation. (7) Equipment configuration of ICU: in terms of basic equipment, the ratio of the total number of ventilators/ICU beds in tertiary and secondary hospitals [0.77% (0.53%, 1.07%), 0.88% (0.63%, 1.38%)], and the ratio of injection pump/ICU beds [1.70% (1.00%, 2.56%), 1.25% (0.75%, 1.88%)] didn't meet the requirements of the Guidelines. The equipment ratio was insuffcient, which means that the basic needs of development had not been met yet. CONCLUSIONS: The development of comprehensive ICU in Inner Mongolia has tended to mature, but there is still a certain gap in the development scale, personnel ratio and instruments and equipment compared with the Guidelines. Moreover, the comprehensive ICU appears the characteristics of relatively weak eastern and western regions, and the overall distribution is uneven. Therefore, it is necessary to increase efforts to invest in the construction of the department of critical care medicine.

Response of simultaneous sulfide and nitrate removal process on acute toxicity of substrate concentration and salinity: Single toxicity and combined toxicity.

Simultaneous sulfide and nitrate removal process has performed excellent to treat nitrogen and sulfur pollutants in wastewater treatment. A high salinity stress poses a great challenge to the treatment of highly saline wastewater containing nitrate and sulfide. In addition, sulfide and nitrates are also toxic for the process, and their high concentration would inhibit the process. Therefore, the current work explores the single acute toxic effect and combined toxic effect of salinity and substrate concentration on the performance of the process from the perspective of toxicology. Considering sulfide and nitrate removal performance as an indicator, the IC50 values of sulfide were 293.20 mg S/L and 572.30 mg S/L, respectively; while those of salinity were 6.14% wt (91.78 mS/cm) and 6.63% wt (98.73 mS/cm), respectively. High substrate concentration or salinity resulted in elemental sulfur generation. The molar ratio of generated elemental sulfur to consumed sulfide(R-Sulfate) was close to 1. The response of nitrate reduction product to the elevating substrate concentration was not obvious, while its response to increasing salinity was on the contrary. With the increasing salinity (1.2% wt to 9.6% wt), molar ratio of generated nitrogen gas to consumed nitrate (R-Nitrogen gas) increased from 0.58 to 1, while molar ratio of generated nitrite to consumed nitrate (R-Nitrite) decreased from 0.43 to 0. Factorial analysis test revealed that the combined acute toxicity of substrate and salinity on sulfide oxidization and nitrate reduction were both antagonistic effects.

Metagenomic analysis of microbial community and metabolic pathway of simultaneous sulfide and nitrite removal process exposed to divergent hydraulic retention times.

The role of hydraulic retention time (HRT) on S0 production was assessed through metagenomics analyses. Considering comprehensive performance for the tested HRTs (0.25-13.33 h), the optimal HRT was 1 h, while respective sulfide and nitrite loading rate could reach 6.84 kg S/(m3·d) and 1.95 kg N/(m3·d), and total S0 yield was 0.36 kg S/(kg (VSS)·d). Bacterial community richness decreased along the shortening of HRT. Microbacterium, Sulfurimonas, Sulfurovum, Paracoccus and Thauera were highly abundant bacteria. During sulfur metabolism, high expression of sqr gene was the main reason of maintaining high desulfurization load, while lacking soxB caused the continuous increase of S0. Regarding nitrogen metabolism, the rapid decrease of nitrite transporter prevented nitrite to enter in cells, which caused a rapid decrease of nitrite removal under extreme HRT. Adjusting HRT is an effective way to enhance S0 production for the application of the simultaneous sulfide and nitrite removal process.

Response difference of simultaneous sulfide and nitrite removal process to different cooling modes.

The effects of various cooling modes (sudden cooling (25℃→10℃) and step cooling (25℃→20℃→15℃→10℃)) on the performance of simultaneous sulfide and nitrite removal process were reported. Regardless of cooling mode adopted, the process maintained good sulfide removal performance, and removal percentage was 100.00%. Considering nitrite removal percentage, the process was more sensitive to step cooling mode (k = 0.06707) in comparison to sudden cooling mode (k = 0.02760). Lowering temperature promoted the transformation from sulfate to elemental sulfur, and it was easier to increase the proportion of elemental sulfur (79.90%) by means of step cooling. The sulfide oxidation rate and nitrite reduction rate were 0.01540 mg /(L∙min) and 0.00354 mg /(L∙min), respectively, in the sudden cooling mode, and 0.01168 mg /(L∙min) and 0.00138 mg /(L∙min), respectively, in the step cooling mode. Low temperature reduced the diversity of microbial community, and Sulfurovum was still a dominant bacterial member in both cooling modes.

Production and characteristics of elemental sulfur during simultaneous nitrate and sulfide removal.

The production and characteristics of elemental sulfur were examined during simultaneous sulfide and nitrate removal, with abiotic assays as control. The biotic assay showed good sulfide and nitrate removal, with the respective removal percentage of which were 90.67-96.88% and 100%. Nitrate reduction resulted in the production of nitrogen gas, while sulfate formed due to sulfide oxidation. The concentration of elemental sulfur in the effluent was greater than that in the sludge, which accounted for 73.70-86.28% of total elemental sulfur produced. Furthermore, the elemental sulfur of the effluent and sludge from the biotic assays was orthorhombic crystal S8. Elemental sulfur was normally distributed in the effluent, but its average diameter increased with the increasing influent sulfide concentration (60-300 mg S/L), where the average diameter increased from 10 (60 mg S/L) to 29 µm (300 mg S/L).

Coupled substrate removal and electricity generation in microbial fuel cells simultaneously treating sulfide and nitrate at various influent sulfide to nitrate ratios.

The current work coupled simultaneous sulfide and nitrate removal in a Microbial Fuel Cell (MFC). The substrate removal and electricity generation were coupled at influent Sulfide to Nitrate molar ratios (S/N ratios) of 5:0, 5:1, 5:2 and 5:3. The sulfide concentrations used included: 60 mg S/L, 300 mg S/L, 540 mg S/L, 780 mg S/L and 1020 mg S/L. The effect of S/N ratio on the performance of substrate removal was greater at higher influent sulfide concentration. The electricity generation also varied at different influent sulfide concentrations and S/N ratios. The number of electrons generated at S/N ratio of 5:2 was the largest at any fixed influent sulfide concentration. The Pearson correlation showed that effluent sulfate concentration and nitrogen gas had significant positive correlations with steady state voltage (or electronic quantity). Moreover, the simulation models were developed to establish the relation between substrate removal and electricity generation at various S/N ratios.