Phytochrome interacting factor regulates stomatal aperture by coordinating red light and abscisic acid.

Stomata are crucial valves coordinating the fixation of carbon dioxide by photosynthesis and water loss through leaf transpiration. Phytochrome interacting factors (PIFs) are negative regulators of red light responses that belong to the basic helix-loop-helix family of transcription factors. Here, we show that the rice (Oryza sativa) PIF family gene OsPIL15 acts as a negative regulator of stomatal aperture to control transpiration in rice. OsPIL15 reduces stomatal aperture by activating rice ABSCISIC ACID INSENSITIVE 5 (OsABI5), which encodes a critical positive regulator of ABSCISIC ACID (ABA) signaling in rice. Moreover, OsPIL15 interacts with the NIGT1/HRS1/HHO family transcription factor rice HRS1 HOMOLOG 3 (OsHHO3) to possibly enhance the regulation of stomatal aperture. Notably, we discovered that the maize (Zea mays) PIF family genes ZmPIF1 and ZmPIF3, which are homologous to OsPIL15, are also involved in the regulation of stomatal aperture in maize, indicating that PIF-mediated regulation of stomatal aperture may be conserved in the plant lineage. Our findings explain the molecular mechanism by which PIFs play a role in red-light-mediated stomatal opening, and demonstrate that PIFs regulate stomatal aperture by coordinating the red light and ABA signaling pathways.

Acute Gastrointestinal Injury in Polytrauma: Special Attention to Elderly Patients.

Background: Acute gastrointestinal injury (AGI) has been documented in critically ill patients, yet there remains a dearth of knowledge regarding its occurrence, predisposing factors, and outcomes in elderly polytrauma patients, a significant but overlooked population. This study aims to examine the frequency, risk factors, and clinical implications of AGI in elderly polytrauma patients. Methods: A retrospective, observational, multicenter study was carried out in two Level I trauma centers, encompassing a cohort of 1054 polytrauma patients from July 2020 to April 2022. Results: A total of 965 consecutive polytrauma patients were recruited who were divided into youth group (n=746) and elderly group (n=219). 73.5% of elderly patients after polytrauma were accompanied by AGI. An increasing ISS (OR=2.957, 95%CI: 1.285-7.714), SI (OR=2.861, 95%CI: 1.372-5.823), serum lactate (OR=2.547, 95%CI: 1.254-5.028), IL-6 (OR=1.771, 95%CI: 1.145-8.768), APTT (OR=1.462, 95%CI: 1.364-4.254) and a decreasing GCS (OR=0.325, 95%CI: 0.116-0.906) were each associated with an increasing risk of AGI in elderly polytrauma patients. Elderly polytrauma patients with AGI were presented relatively high 28-day mortality (40.4%) and super high 60-day mortality (61.2%) compared with elderly group without AGI and youth group with AGI. The area under the curve for predicting 28-day mortality in elderly polytrauma patients with AGI was 0.93 for AGI-III,IV with 96% sensitivity and 87% specificity. Conclusion: Elderly patients have a higher incidence and a worse prognosis of AGI after polytrauma. ISS, GCS, SI, serum lactate, IL-6, and APTT are identified as reliable prognostic markers to distinguish the AGI and N-AGI in elderly polytrauma patients. AGI-III,IV was the independent predictor of mortality in elderly polytrauma patients with AGI.

Ammonia oxidizing bacteria (AOB) denitrification and bacterial denitrification as the main culprit of high N2O emission in SBR with low C/N ratio wastewater.

A large amount of greenhouse gas nitrous oxide (N2O) will be produced during the biological nitrogen removal process for organic wastewater of low C/N ratio. One of the effective methods to solve this problem is to incorporate inexpensive carbon source. In this study, raw wastewater (RW) from pig farm, that was not anaerobically digested, was utilized as exogenous carbon in both A/O and SBR aerobic reactor to treat liquid digestate with high ammonia nitrogen and low C/N ratio. The results showed that N2O emission in SBR was higher than that of A/O process under the same nitrogen load. The N2O conversion in the biological nitrogen removal process was investigated by the strategy of integrating stable isotope method and metagenomics. The δO18-N2O, δN15-N2O, and SP values of the SBR were closer to the denitrification values of Ammonia-Oxidizing Bacteria (AOB) than those of A/O. The abundance of AOB in the SBR reactor was higher than that in the A/O reactor, while the abundance of denitrifying bacteria was lower. The amoA/B/C gene abundance in the SBR was greater than that in the A/O, and the NOS gene abundance was the opposite. The results indicated that both AOB denitrification and bacterial denitrification led to the increase of N2O emissions of the SBR.

Application of the Electromagnetic Method to the Spatial Distribution of Subsurface Saline and Fresh Water in the Coastal Mudflat Area of Jiangsu Province.

Interfacial zones straddling terrestrial and marine realms, colloquially known as mudflats, epitomize a dynamic nexus between these environments and are fundamental to the coastal ecosystem. The investigation of these regions is paramount for facilitating infrastructural developments including ports, wharfs, cross-sea bridges, and the strategic utilization of freshwater resources sequestered from mainland islands amid ongoing economic progress. Terrestrial realms conventionally employ electromagnetic techniques as efficacious modalities to delineate subterranean geological information, encompassing structural details and water-bearing strata. However, the peculiar topographic and geological nuances of mudflat regions pose substantial challenges for the efficacious application of electromagnetic methodologies. The present paper endeavors to address these challenges by suggesting innovative modifications to the existing instrumentation and evolving novel data acquisition techniques specifically tailored for electromagnetic exploration within mudflat environments. This paper delves into the electrical characteristics of water-bearing layers within mudflats, and ascertains details pertaining to the subterranean structure and the spatial distribution of fresh and saline water resources, through the holistic interpretation of a multitude of profiles.

N-Acyl-Homoserine Lactone (AHL)-Mediated Microalgal-Bacterial Communication Driving Chlorella-Activated Sludge Bacterial Biofloc Formation.

N-acyl-homoserine lactones (AHLs) as autoinducers of Gram-negative bacteria for quorum sensing regulation have shown positive effects on the production of aromatic proteins in extracellular polymeric substances (EPSs) during bioflocculation. To investigate the role of AHLs in aromatic protein production, a Chlorella-bacteria system with great bioflocculation was established via fed-batch cultivation. Tryptophan and aromatic proteins as the main compounds in the EPS of bioflocs showed an increasing trend during fed-batch cultivation. The Chlorella cells only secreted tryptophan rather than aromatic proteins during axenic cultivation. N-dodecanoyl-l-homoserine lactone (C12-HSL) was correlated with the flocculation activity and extracellular protein content of bioflocs during fed-batch cultivation. The addition of exogenous C12-HSL enhanced the flocculation activity of the Chlorella-bacteria system and aromatic protein production in the EPS. Chlorella cells sensed exogenous C12-HSL and significantly upregulated the aromatic protein synthesis pathway during axenic cultivation. In addition, vanillin as a quorum-sensing inhibitor suppressed the positive effect of C12-HSL on flocculation activity and aromatic protein production and synthesis. This result indicated that vanillin intercepts the response of Chlorella cells to C12-HSL. Overall, C12-HSL is supposed to be an important signal molecule to achieve communication between Chlorella and Gram-negative bacteria and subsequently induce Chlorella cells to produce aromatic proteins for biofloc formation.

Nitrification performance evaluation of activated sludge under high potassium ion stress during high-ammonia nitrogen organic wastewater treatment.

The recycling reverse osmosis (RO) membrane concentrate of some high-ammonia nitrogen (NH4+-N) organic wastewater to the biological unit could cause potassium ion (K+) accumulation, thereby affecting the removal of NH4+-N by activated sludge. Thus, the effects of high K+ stress on activated sludge nitrification performance was studied. The results showed that the high K+ stress promoted the floc sludge to produce more extracellular polymers (EPS), which accelerated the sludge sedimentation and enriched the biomass in sequential batch reactors (SBRs). The ammonia oxidation process and nitrite (NO2--N) oxidation process were further analyzed in the nitrification process. High K+ stress enriched ammonia oxidizing bacteria (AOB), which ensured the efficient ammonia oxidation process in SBRs, and ensured the removal rate of NH4+-N was maintained above 93%. However, high K+ stress (15g/L KCl) inhibited the activity of NO2--N oxidizing bacteria (NOB) and reduced the abundance of NOB, thus leading to the accumulation of NO2--N, and finally worsened the nitrification performance of activated sludge. In short, the performance of activated sludge will not be inhibited when the K+ in the wastewater does not exceed 5.23 g/L. The results could provide a reference for the optimization of the biological performance in treating high-NH4+-N organic wastewater with activated sludge coupled RO membrane treatment process.

Response of alternative splice isoforms of OsRad9 gene from Oryza sativa to environmental stress.

Rad9 protein plays an important role in cell-cycle checkpoint signal transduction in human and yeast cells, but knowledge about Rad9 in plants is limited. This study reports that the Rad9 gene of rice can generate the transcript products OsRad9.1 and OsRad9.2 through alternative splicing. OsRad9.1, with all nine exons, is the main cell-cycle checkpoint protein involved in the response of rice to genotoxic stresses (ultraviolet radiation and antibiotic stress), environmental stresses (drought, salt, and heavy metal stress), and auxin stimuli (2,4-D, IAA, and IBA). Meanwhile, transcript isoform OsRad9.2, which lost exon7 and exon8, showed different preferential stimulation effects on these stresses and pollen development duration. These results might indicat that besides the monitoring and repair of DNA damage, Rad9 might involve in the development of pollen.

Transcriptomic and physiological analysis of common duckweed Lemna minor responses to NH4(+) toxicity.

BACKGROUND: Plants can suffer ammonium (NH4 (+)) toxicity, particularly when NH4 (+) is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 (+) toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor responding to high NH4 (+) may provide us some interesting and useful information not only in toxic processes, but also in tolerance mechanisms. RESULTS: The L. minor cultured in the Hoagland solution were used as the control (NC), and in two NH4 (+) concentrations (NH4 (+) was the sole nitrogen source), 84 mg/L (A84) and 840 mg/L (A840) were used as stress treatments. The NH4 (+) toxicity could inhibit the growth of L. minor. Reactive oxygen species (ROS) and cell death were studied using stained fronds under toxic levels of NH4 (+). The malondialdehyde content and the activities of superoxide dismutase and peroxidase increased from NC to A840, rather than catalase and ascorbate peroxidase. A total of 6.62G nucleotides were generated from the three distinct libraries. A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained. All the DEGs could be clustered into 7 profiles. Most DEGs were down-regulated under NH4 (+) toxicity. The genes required for lignin biosynthesis in phenylpropanoid biosynthesis pathway were up-regulated. ROS oxidative-related genes and programmed cell death (PCD)-related genes were also analyzed and indicated oxidative damage and PCD occurring under NH4 (+) toxicity. CONCLUSIONS: The first large transcriptome study in L. minor responses to NH4 (+) toxicity was reported in this work. NH4 (+) toxicity could induce ROS accumulation that causes oxidative damage and thus induce cell death in L. minor. The antioxidant enzyme system was activated under NH4 (+) toxicity for ROS scavenging. The phenylpropanoid pathway was stimulated under NH4 (+) toxicity. The increased lignin biosynthesis might play an important role in NH4 (+) toxicity resistance.

Immobilization of phosphorus in cow manure during hydrothermal carbonization.

The surplus of manure phosphorus (P) with increasing livestock production might pose a risk of P loss to the environment due to the high mobility of P in manure. Thus, there is an increasing need to mitigate P loss from manure. This study aimed to investigate the effect of hydrothermal carbonization (HTC) on the immobilization of P in cow manure. The results demonstrated that the P content in cow manure was increased substantially by ∼20% after HTC, while the water-extractable P (WEP) and Mehlich-3-extractable P (MEP) in manure was reduced significantly by >80% and 50%, respectively. The decrease in P solubility might result from the increased apatite P (increased by >85%) and decreased soluble Ca (decreased by ∼50%) after HTC. These results suggested that HTC could be an efficient strategy to immobilize P in cow manure, thereby potentially mitigating the P loss problem from cow manure.

[Observation on the efficacy of continuous veno-venous hemodia-filtration combined with hemoperfusion HA380 in the treatment of 15 cases of heat stroke with multiple organ dysfunction syndrome].

OBJECTIVE: To investigate the clinical efficacy of continuous veno-venous hemodia-filtration (CVVHDF) combined with hemoperfusion (HP) HA380 in the treatment of heat stroke patients with multiple organ dysfunction syndrome (MODS). METHODS: A retrospective and observational study was conducted. A total of 15 patients with heat stroke combined with MODS who were admitted to the department of intensive care unit (ICU) of Suizhou Central Hospital/Hubei University of Medicine from July to September 2022 were selected as the study objects. All 15 patients were treated with CVVHDF combined with HA380 based on the comprehensive management strategy for severe illness. Organ function indicators [including total bilirubin (TBil), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), creatinine (Cr), cardiac troponin T (cTnT), myoglobin (Myo), MB isoenzyme of creatine kinase (CK-MB), sequential organ failure assessment (SOFA)] and inflammatory indicators [including white blood cell count (WBC), neutrophil count (NEU), C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6)] were collected. The improvements of the above indexes at admission, after the first HP, after the second HP, after the third HP, and on the 5th day of treatment were compared. Combined with the clinical outcome of patients, the comprehensive efficacy of CVVHDF combined with HA380 in the treatment of severe heat radiation disease was evaluated. RESULTS: There were 10 males and 5 females among the 15 patients. The average age was (64.5±11.5) years old. There were 6 cases of classical heat stroke and 9 cases of exertional heat stroke. Glasgow coma scale (GCS) was 3-8 at admission; SOFA score was 9-17 within 12 hours after admission; acute physiology and chronic health evaluation II (APACHE II) was 25-45 within 24 hours after admission. After treatment, the IL-6 level and SOFA score gradually decreased, and there were significant differences in the decrease after the second HP compared to admission [IL-6 (ng/L): 48.37 (15.36, 113.03) vs. 221.90 (85.87, 425.90), SOFA: 8.3±3.3 vs. 11.1±2.4, both P < 0.05]. The PCT level reached its peak after the first HP [12.51 (6.07, 41.65) µg/L], and then gradually decreased, and the difference was statistically significant after the third HP [1.26 (0.82, 5.40) µg/L, P < 0.05]. Compared those at admission, Cr level significantly improved after the first HP (µmol/L: 66.94±25.57 vs. 110.80±31.13, P < 0.01), Myo significantly decreased after the second HP [µg/L: 490.90 (164.98, 768.05) vs. 3 000.00 (293.00, 3 000.00), P < 0.05], After the third HP, the CK level also showed significant improvement [U/L: 476.0 (413.0, 922.0) vs. 2 107.0 (729.0, 2 449.0), P < 0.05]. After CVVHDF combined with 3 times HP treatment, the patient's inflammatory response was gradually controlled and organ function gradually recovered. On the 5th day of the disease course, WBC, PCT and IL-6 levels were significantly improved compared to admission, and AST, CK, LDH, Cr, Myo, CK-MB, and SOFA score were significantly corrected compared with those on admission. The 24-hour survival rate of 15 patients was 86.67%, and the 24-hour, 7-day and 28-day survival rates were both as high as 73.33%. The average mechanical ventilation time of 11 surviving patients was (101.8±22.0) hours, the average continuous renal replacement therapy (CRRT) time was (58.8±11.0) hours, the average length of ICU stay was (6.3±1.0) days, and the average total hospitalization was (14.6±5.2) days. CONCLUSIONS: CVVHDF combined with HP HA380 in the treatment of heat stroke patients with MODS can effectively improve organ function and alleviate the inflammatory storm, which is an effective means to improve the rescue rate and reduce the mortality of severe heat stroke patients.

Receptor Plants Alleviated Allelopathic Stress from Invasive Chenopodium ambrosioides L. by Upregulating the Production and Autophagy of Their Root Border Cells.

Chenopodium ambrosioides L. is an invasive plant native to the Neotropics that has seriously threatened the ecological security of China, and allelopathy is one of the mechanisms underlying its successful invasion. Maize (Zea mays L.) and soybean (Glycine max (L.) Merr.), as the main food crops, are usually affected by C. ambrosioides in their planting areas. The purpose of this study was to investigate the ultrastructure, autophagy, and release-related gene expression of receptor plant root border cells (RBCs) after exposure to volatile oil from C. ambrosioides and its main component α-terpene, which were studied using maize and soybean as receptor plants. The volatiles inhibited root growth and promoted a brief increase in the number of RBCs. As the volatile concentration increased, the organelles in RBCs were gradually destroyed, and intracellular autophagosomes were produced and continuously increased in number. Transcriptomic analysis revealed that genes involved in the synthesis of the plasma membrane and cell wall components in receptor root cells were significantly up-regulated, particularly those related to cell wall polysaccharide synthesis. Meanwhile, polygalacturonase and pectin methylesterases (PME) exhibited up-regulated expression, and PME activity also increased. The contribution of α-terpene to this allelopathic effect of C. ambrosioides volatile oil exceeded 70%. Based on these results, receptor plant root tips may increase the synthesis of cell wall substances while degrading the intercellular layer, accelerating the generation and release of RBCs. Meanwhile, their cells survived through autophagy of RBCs, indicating the key role of RBCs in alleviating allelopathic stress from C. ambrosioides volatiles.

Treatment and utilization of swine wastewater - A review on technologies in full-scale application.

The management of swine wastewater has become the focus of attention in the farming industry. The disposal mode of swine wastewater can be classified as field application of treated waste and treatment to meet discharge standards. The status of investigation and application of unit technology in treatment and utilization such as solid-liquid separation, aerobic treatment, anaerobic treatment, digestate utilization, natural treatment, anaerobic-aerobic combined treatment, advanced treatment, are reviewed from the full-scale application perspective. The technologies of anaerobic digestion-land application is most appropriate for small and medium-sized pig farms or large pig farms with enough land around for digestate application. The process of "solid-liquid separation-anaerobic-aerobic-advanced treatment" to meet the discharge standard is most suitable for large and extra-large pig farms without enough land. Poor operation of anaerobic digestion unit in winter, hard to completely utilize liquid digestate and high treatment cost of digested effluent for meeting discharge standard are established as the main difficulties.

Venous Thrombus Embolism in Polytrauma: Special Attention to Patients with Traumatic Brain Injury.

Venous thrombus embolism (VTE) is common after polytrauma, both of which are considered significant contributors to poor outcomes and mortality. Traumatic brain injury (TBI) is recognized as an independent risk factor for VTE and one of the most common components of polytraumatic injuries. Few studies have assessed the impact of TBI on the development of VTE in polytrauma patients. This study sought to determine whether TBI further increases the risk for VTE in polytrauma patients. A retrospective, multi-center trial was performed from May 2020 to December 2021. The occurrence of venous thrombosis and pulmonary embolism from injury to 28 days after injury was observed. Of 847 enrolled patients, 220 (26%) developed DVT. The incidence of DVT was 31.9% (122/383) in patients with polytrauma with TBI (PT + TBI group), 22.0% (54/246) in patients with polytrauma without TBI (PT group), and 20.2% (44/218) in patients with isolated TBI (TBI group). Despite similar Glasgow Coma Scale scores, the incidence of DVT in the PT + TBI group was significantly higher than in the TBI group (31.9% vs. 20.2%, p < 0.01). Similarly, despite no difference in Injury Severity Scores between the PT + TBI and PT groups, the DVT rate was significantly higher in the PT + TBI group than in the PT group (31.9% vs. 22.0%, p < 0.01). Delayed anticoagulant therapy, delayed mechanical prophylaxis, older age, and higher D-dimer levels were independent predictive risk factors for DVT occurrence in the PT + TBI group. The incidence of PE within the whole population was 6.9% (59/847). Most patients with PE were in the PT + TBI group (64.4%, 38/59), and the PE rate was significantly higher in the PT + TBI group compared to the PT (p < 0.01) or TBI (p < 0.05) group. In conclusion, this study characterizes polytrauma patients at high risk for VTE occurrence and emphasizes that TBI markedly increases the incidence of DVT and PE in polytrauma patients. Delayed anticoagulant therapy and delayed mechanical prophylaxis were identified as the major risk factors for a higher incidence of VTE in polytrauma patients with TBI.

The long-term effect of glutaraldehyde on the bacterial community in anaerobic ammonium oxidation reactor.

A 160-day incubation was performed with two anammox reactors (GA and CK) to investigate the effect of glutaraldehyde. The results indicated that anammox bacteria were very sensitive when glutaraldehyde in GA reactor increased to 40 mg/L, the nitrogen removal efficiency sharply decreased to 11%, only one-quarter of CK. Glutaraldehyde changed spatial distribution of exopolysaccharides, caused anammox bacteria (Brocadia CK_gra75) to disassociate from granules (24.70% of the reads in CK but only 14.09% in GA granules). Metagenome analysis indicated glutaraldehyde led to the denitrifier community succession from strains without nir (nitrite reductase) and nor (nitric oxide reductases) genes to those with them, and the rapid growth of denitrifiers with NodT (an outer membrane factor)-related efflux pumps replacing those with another TolC -related ones. Meanwhile, Brocadia CK_gra75 lacks the NodT proteins. This study provides important insight into community adaptation and potential resistance mechanism in an active anammox community after exposure to disinfectant.

Transcriptome profiling of Zymomonas mobilis under furfural stress.

Furfural from lignocellulosic hydrolysates is the prevalent inhibitor to microorganisms during cellulosic ethanol production, but the molecular mechanisms of tolerance to this inhibitor in Zymomonas mobilis are still unclear. In this study, genome-wide transcriptional responses to furfural were investigated in Z. mobilis using microarray analysis. We found that 433 genes were differentially expressed in response to furfural. Furfural up- or down-regulated genes related to cell wall/membrane biogenesis, metabolism, and transcription. However, furfural has a subtle negative effect on Entner-Doudoroff pathway mRNAs. Our results revealed that furfural had effects on multiple aspects of cellular metabolism at the transcriptional level and that membrane might play important roles in response to furfural. This research has provided insights into the molecular response to furfural in Z. mobilis, and it will be helpful to construct more furfural-resistant strains for cellulosic ethanol production.

(S)-N-Phenyl-tert-butane-sulfinamide.

The asymmetric unit of the title compound, C(10)H(15)NOS, contains two independent mol-ecules with similar conformations. In the crystal, mol-ecules are linked in a head-to-tail fashion by N-H⋯O hydrogen bonds into chains running along the b axis. The absolute configuration was assigned on the basis of known chirality of the parent compound.

(R)-N-(Biphenyl-4-yl)-tert-butane-sulfinamide.

In the title compound, C(16)H(19)NOS, the dihedral angle between the two aromatic rings is 38.98 (8)°. The crystal structure is stabilized by N-H⋯O hydrogen bonds, which link neighbouring mol-ecules into chains running parallel to the a axis.

(R)-N-(3-Meth-oxy-phen-yl)-tert-butane-sulfinamide.

The title compound, C(11)H(17)NO(2)S, was obtained by the reaction of (R)-tert-butane-sulfinamide with 3-meth-oxy-phenyl bromide in toluene. In the crystal, mol-ecules inter-act head-to-tail through N-H⋯O and C-H⋯O hydrogen bonds, forming one-dimensional chains parallel to the a axis.

Constructed microalgal-bacterial symbiotic (MBS) system: Classification, performance, partnerships and perspectives.

The microalgal-bacterial symbiotic (MBS) system shows great advantages in the synchronous implementation of wastewater treatment and nutrient recovery. To enhance the understanding of different MBS systems, this review summarizes reported MBS systems and proposes three patterns according to the living state of microalgae and bacteria. They are free microalgal-bacterial (FMB) system, attached microalgal-bacterial (AMB) system and bioflocculated microalgal-bacterial (BMB) system. Compared with the other two patterns, BMB system shows the advantages of microalgal biomass harvesting and application. To further understand the microalgal-bacterial partnerships in the bioflocculation of BMB system, this review discusses bioflocs characteristics, extracellular polymeric substances (EPS) properties and production, and the effect of microalgae/bacteria ratio and microalgal strains on the formation of bioflocculation. Microalgal biomass production and application are important for BMB system development in the future. Food processing wastewater characterized by high biodegradability and low toxicity should be conducive for microalgal cultivation. In addition, exogenous addition of functional bacteria for nutrient removal and bioflocculation formation would be a crucial research direction to facilitate the large-scale application of BMB system.

Multifactorial Shock: A Neglected Situation in Polytrauma Patients.

Background: Shock after traumatic injury is likely to be hypovolemic, but different types of shock (distributive shock, obstructive shock, or cardiogenic shock) can occur in combination, known as multifactorial shock. Multifactorial shock is a neglected area of study, and is only reported sporadically. Little is known about the incidence, characteristics, and outcomes of multifactorial shock after polytrauma. Methods: A retrospective, observational, multicenter study was conducted in four Level I trauma centers involving 1051 polytrauma patients from June 2020 to April 2022. Results: The mean Injury Severity Score (ISS) was 31.1, indicating a severely injured population. The most common type of shock in the early phase after polytrauma (≤48 h) is hypovolemic shock (83.2%), followed by distributive shock (14.4%), obstructive shock (8.7%), and cardiogenic shock (3.8%). In the middle phase after polytrauma (>48 h or ≤14 days), the most common type of shock is distributive shock (70.7%), followed by hypovolemic shock (27.2%), obstructive shock (9.9%), and cardiogenic shock (7.2%). Multifactorial shock accounted for 9.7% of the entire shock population in the early phase and 15.2% in the middle phase. In total, seven combinations of multifactorial shock were described. Patients with multifactorial shock have a significantly higher complication rate and mortality than those with single-factor shock. Conclusions: This study characterizes the incidence of various types of shock in different phases after polytrauma and emphasizes that different types of shock can occur simultaneously or sequentially in polytrauma patients. Multifactorial shock has a relatively high incidence and mortality in polytrauma patients, and trauma specialists should be alert to the possibility of their occurrence.