Prognostic factors associated with mortality in mechanically ventilated patients in the intensive care unit: A single-center, retrospective cohort study of 905 patients.

Data on outcomes of patients receiving mechanical ventilation (MV) in China are scarce.To investigate factors associated with the prognosis of patients given MV in the intensive care unit (ICU).A 12-year (January 1, 2006-December 31, 2017) retrospective cohort study.ICU of Beijing Geriatric Hospital, China.A total of 905 patients aged ≥16 years given MV during the study period.None.Among 905 patients included (610 men; median age, 78 years; Acute Physiology and Chronic Health Evaluation [APACHE]-II score, 27.3 ±â€Š8.9), 585 survived (388 men; median age, 77 years; average APACHE-II score, 25.6 ±â€Š8.4), and 320 died in the ICU (222 men; median age, 78 years; APACHE-II score, 30.6 ±â€Š8.9). All-cause ICU mortality was 35.4%. In patients aged <65 years, factors associated with ICU mortality were APACHE-II score (odds ratio [OR], 1.108; 95% confidence interval [95% CI], 1.021-1.202; P = .014), nosocomial infection (OR, 6.618; 95% CI, 1.065-41.113; P = .043), acute kidney injury (OR, 17.302; 95% CI, 2.728-109.735; P = .002), invasive hemodynamic monitoring (OR, 10.051; 95% CI, 1.362-74.191; P = .024), MV for cardiopulmonary resuscitation (OR, 0.122; 95% CI, 0.016-0.924; P = .042), duration of MV (OR, 0.993; 95% CI, 0.988-0.998; P = .008), successful weaning from MV (OR, 0.012; 95% CI, 0.002-0.066; P < .001), and renal replacement therapy (OR, 0.039; 95% CI, 0.005-0.324; P = .003). In patients aged ≥65 years, factors associated with mortality were APACHE-II score (OR, 1.062; 95% CI, 1.030-1.096; P < .001), nosocomial infection (OR, 2.427; 95% CI, 1.359-4.334; P = .003), septic shock (OR, 2.017; 95% CI, 1.153-3.529; P = .014), blood transfusion (OR, 1.939; 95% CI, 1.174-3.202; P = .010), duration of MV (OR, 0.999; 95% CI, 0.999-1.000; P = .043), and successful weaning from MV (OR, 0.027; 95% CI, 0.015-0.047; P < .001).APACHE-II score, successful weaning, and nosocomial infection in the ICU are independently associated with the prognosis of patients given MV in the ICU.

[Analysis of factors affecting the prognosis of ICU patients by multiple logistic regression model: a retrospective cohort study of 1 299 patients in 12 consecutive years].

OBJECTIVE: To explore the prognostic factors of intensive care unit (ICU) patients. METHODS: A retrospective cohort study was conducted. The clinical data of patients admitted to ICU of Beijing Geriatric Hospital from January 2005 to December 2016 were collected. According to the prognosis, the patients were divided into death group and survival group, and the mortality trend with time and age was observed. Survival and death were treated as dependent variables, while the gender, age, reason of ICU admission, acute physiology and chronic health evaluation II (APACHE II) score, whether undergoing invasive mechanical ventilation (MV), invasive MV reason, duration of invasive MV, whether successful weaning, whether ICU nosocomial infection, hospital acquired pneumonia (HAP), central line-associated bloodstream infection (CLABSI), acute kidney injury (AKI) occurred, whether undergoing continuous blood purification (CBP), whether septic shock occurred, whether undergoing invasive hemodynamic monitoring or blood transfusion and length of ICU stay were used as the independent variables. First, the clinical data was analyzed by univariate analysis. Second, the independent variables influencing the dependent variable were analyzed by logistic regression analysis to screen out prognostic factors of ICU patients. RESULTS: During the study period, 1 325 patients were treated, 26 patients with missing data, 1 299 patients in final group, 865 patients in survival group, and 434 in death group. The proportion of men in the patients was larger (67.7%), and the age span was larger (16-105 years old). The mortality rate in different years showed no significant difference (χ 2 = 16.712, P = 0.117), and with the increase of age, the mortality rate of ICU showed an upward trend (χ 2 = 16.399, P = 0.022). The univariate analysis showed that ICU deaths were unrelated to gender, but associated with age, APACHE II score, invasive MV, invasive MV reason, duration of invasive MV, successful weaning, ICU nosocomial infection, HAP, CLABSI, AKI, septic shock, whether CBP or invasive hemodynamic monitoring, blood transfusion, the reason of ICU admission and the length of ICU stay (all P < 0.05). The relevant factors with statistical difference found in univariate analysis were analyzed in logistic regression analysis, which showed that whether successful weaning [odds ratio (OR) = 0.016, 95% confidence interval (95%CI) = 0.010-0.025], and whether AKI (OR = 3.917, 95%CI = 2.331-6.582) or septic shock occurred (OR = 2.808, 95%CI = 1.604-4.915) were the dependent variables of death or survival (all P = 0.000). Regression coefficient (ß value) of successful weaning was -4.155, suggesting that unsuccessful weaning patients were likely to die. The ß value of AKI and septic shock was 1.365 and 1.033, suggesting that the patients with AKI or septic shock were more likely to die. CONCLUSIONS: Whether the success of weaning, whether the occurrence of AKI or septic shock are independent prognostic factors for the prognosis of ICU patients. Measures for the prevention of the above three aspects could improve the prognosis of ICU patients.

Synthesis, Characterization, Thermal Stability and Sensitivity Properties of New Energetic Polymers-PVTNP-g-GAPs Crosslinked Polymers.

A series of energetic polymers, poly(vinyl 2,4,6-trinitrophenylacetal)-g-polyglycidylazides (PVTNP-g-GAPs), were synthesized via cross-linking reactions of PVTNP with three different molecular weight GAPs using toluene diisocyanate as the cross-linking agent. The structures of these energetic polymers were characterized by ultraviolet visible spectra (UV⁻Vis), attenuated total reflectance-Fourier transform-infrared spectroscopy (ATR-FTIR), and nuclear magnetic resonance spectrometry (NMR). The glass-transition temperatures of these energetic polymers were measured with differential scanning calorimetry (DSC) method, and the results showed that all the measured energetic polymers have two distinct glass-transition temperatures. The thermal decomposition behaviors of these energetic polymers were evaluated by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and thermogravimetric analysis tandem infrared spectrum (TGA-IR). The results indicated that all the measured energetic polymers have excellent resistance to thermal decomposition up to 200 °C, and the initial thermal decomposition was attributed to the breakdown of azide group. Moreover, the sensitivity properties of these energetic polymers were measured with the national military standard methods and their compatibilities with the main energetic components of 2,4,6-trinitrotoluene (TNT)-based melt-cast explosive were evaluated by using the DTA method. The results indicate that these energetic polymers have feasible mechanical sensitivities and can be safely used with TNT, cyclotetramethylene tetranitramine (HMX), 1,1-diamino-2,2-dinitroethene (FOX-7), 3-nitro-1,2,4-triazol-5-one (NTO) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB).

Two important factors influencing shock sensitivity of nitro compounds: Bond dissociation energy of X-NO2 (X = C, N, O) and Mulliken charges of nitro group.

DFT/BLYP/DNP is employed to calculate bond dissociation energy of X-NO(2) (X = C, N, O) and Mulliken charges of nitro group of 14 kinds of nitro compounds, and partial least squares approximation is applied to linearly fit their shock initiation pressure (p(90%,TMD)). It is found that the fitted values are in good agreement with the experimental shock initiation pressures. The fitted model is used to predict the shock initiation pressures of two kinds of explosives, TNB and TNETB. The predictive values are in accordance with experimental ones. It reflects that bond dissociation energy of X-NO(2) (X = C, N, O) and Mulliken charge of nitro groups may be the important factors influencing the shock sensitivity of nitro compounds. On the basis of the fitted model, bond dissociation energy of X-NO(2) (X = C) and Mulliken charges of nitro groups of another 14 kinds of heterocyclic nitro compounds are in consideration to predict shock sensitivity. This work is meaningful in further understanding the shock mechanism and helpful to the design and synthesis of novel energetic materials.

Cooperative effects, strengths of hydrogen bonds, and intermolecular interactions in circular cis, trans-cyclotriazane clusters (n = 3-8).

Based on Becke's three parameter functional [J. Chem. Phys. 98, 5648 (1993)] of density functional theory (DFT) with the correlation of Lee-Yang-Parr [Phys. Rev. B 37, 785 (1988)] (DFT/B3LYP), the natural bond orbital (NBO) analysis, the Bader's theory of atoms in molecule (AIM), our calculations indicate that as cluster size (n) increases, the n-dependent cooperative changes in the lengths of the N...H H bonds (HBs) and N-H bonds, the N-H stretching frequencies and intensities, and the n(N)-->sigma*(N-H) charge transfers are observed to be pervasive in the circular cis, trans-cyclotriazane clusters (n = 3-8), which is very different from the linear cis, trans-cyclotriazane clusters reported in previous work. According to the NBO and AIM theories, the cooperativity of the intermolecular n(N)-->sigma*(N-H) interaction leads to the n-dependent N...H contractions. In this way, the stronger N...H bond is formed, as reflected in the increase in their rho(r(cp)) values. This increased electron density is translated into the improved capacity to concentrate electrons at the HB bond critical point (BCP), i.e., a higher potential energy V(r(cp)). On the other hand, stronger repulsion is also activated to counteract the contraction, which is reflected in the increased G(r(cp)) value that gives the tendency of the system to dilute electrons at the HB BCP. In terms of the three-body symmetry-adapted perturbation theory (three-body SAPT), the induction nonadditivity accounts for up to 97% of the nonadditive energy in the circular trimer. It can believed that the marked cooperativity of the n(N)-->sigma*(N-H) interactions is of nonadditive induction in nature. The N...H formation and nature of cooperativity in the circular clusters differ from those in the linear clusters that have been reported previously. According to the SAPT(DFT) method which is a combination of SAPT with the asymptotically corrected DFT, the cis, trans-cyclotriazane systems should contain remarkable dispersion interactions. However, the short-range dispersion cannot be reproduced thoroughly by DFT/B3LYP. A quantum cluster equilibrium model illustrates the neglected dispersion energies and the nonadditive energies can affect markedly the properties of the liquid consisting of the circular clusters.

Density functional theory study of the properties of N-H...N, non-cooperativities, and intermolecular interactions in linear trans-diazene clusters up to ten molecules.

We investigate aspects of N-H...N hydrogen bonding in the linear trans-diazene clusters (n=2-10) such as the N...H and N-H lengths, n(N) --> sigma(N-H) interactions, N...H strengths, and frequencies of the N-H stretching vibrations utilizing the DFT/B3LYP theory, the natural bond orbital (NBO) method, and the theory of atoms in molecules (AIM). Our calculations indicate that the structure and energetics are qualitatively different from the conventional H-bonded systems, which usually exhibit distinct cooperative effects, as cluster size increases. First, a shortening rather than lengthening of the N-H bond is found and thus a blue rather than red shift is predicted. Second, for the title clusters, any sizable cooperative changes in the N-H and N...H lengths, n(N) --> sigma(N-H) charge transfers, N...H strengths, and frequencies of the N-H stretching vibrations for the linear H-bonded trans-diazene clusters do not exist. Because the n(N) --> sigma(N-H) interaction hardly exhibits cooperative effects, the capability of the linear trans-diazene cluster to localize electrons at the N...H bond critical point is almost independent of cluster size and thereby leads to the noncooperative changes in the N...H lengths and strengths and the N-H stretching frequencies. Third, the dispersion energy is sizable and important; more than 30% of short-range dispersion energy not being reproduced by the DFT leads to the underestimation of the interaction energies by DFT/B3LYP. The calculated nonadditive interaction energies show that, unlike the conventional H-boned systems, the trans-diazene clusters indeed exhibit very weak nonadditive interactions.

Theoretical study of properties of H bonds and intermolecular interactions in linear cis-,trans-cyclotriazane clusters (n = 2-8).

Our calculations based upon Becke's three-parameter functional of density-functional theory (DFT) with the correlation of Lee, Yang, and Parr (B3LYP), natural bond orbital, and atoms in molecule indicate that in drastic contrast to most H-bonded systems, the anticooperative and cooperative effects coexist in the linear H-bonded cis-,trans (c,t)-cyclotriazane clusters (n = 2-8). As cluster size increases, the properties along the H-bonded chains at trans-positions take on the unexpectedly anticooperative changes which are reflected in elongation of the N...H hydrogen bonds, frequency blueshift in the N-H stretching vibrations, decay in the n(N)-->sigma*(N-H) charge transfers, and weakening of strengths of the N...H bonds. And the cooperative changes in the corresponding properties for the cis- H-bonded chains are observed to be concurrent with the anticooperativities. The rise and fall in the n(N)-->sigma*(N-H) interactions cause increment and decrement in capacities of the clusters to concentrate electrons at the bond critical points of the N...H bonds, and thereby leading to the cooperative and the anticooperative changes especially in the N...H lengths and the N-H stretching frequencies. In terms of three-body symmetry-adapted perturbation theory (three-body SAPT), the first exchange nonadditivity plays a more important role in stabilizing trimer than the nonadditive induction. However, the dominance of the first exchange nonadditivity in three-body interaction unexpectedly triggers the anticooperative effect that counteracts the concurrent cooperative effect. According to the SAPT(DFT), which is a combination of SAPT with asymptotically corrected DFT, DFT/B3LYP is able to succeed in describing the electrostatic, exchange, and induction components, but fails to yield satisfactory interaction energies due to the fact that about 40% of short-range dispersion energy is neglected by the DFT, which is different from many H-bonded described well by the DFT. A quantum cluster equilibrium model illustrates that the c,t-cyclotriazane liquid phase exhibits a weak cooperative effect.

Cooperative effects and strengths of hydrogen bonds in open-chain cis-triaziridine clusters (n = 2-8): a DFT investigation.

We employ DFT/B3LYP method to investigate linear open-chain clusters (n = 2-8) of the cis-triaziridine molecule that is a candidate molecule for high energy density materials (HEDM). Our calculations indicate that the pervasive phenomena of cooperative effects are observed in the clusters of n = 3-8, which are reflected in changes in lengths of N...H hydrogen bonds, stretching frequencies, and intensities of N-H bonds, dipole moments, and charge transfers as cluster size increases. The n(N) --> sigma*(N-H) interactions, i.e., the charge transfers from lone pairs (n(N)) of the N atoms into antibonds (sigma*) of the N-H bonds acting as H-donors, can be used to explain the observed cooperative phenomena. The approaches based upon natural bond orbital (NBO) method and theory of atoms in molecule (AIM) to evaluating N...H strengths are found to be equivalent. In the process of N...H bonding, cooperative nature of n(N) --> sigma*(N-H) interactions promotes formation of stronger N...H bonds as reflected in increases in the capacities of cis-triaziridine clusters to concentrate electrons at the bond critical points of N...H bonds. The calculated nonadditive energies also show that the cooperative effects due to n(N) --> sigma*(N-H) interactions indeed provide additional stabilities for the clusters.

Investigation of correlation between impact sensitivities and nitro group charges in nitro compounds.

A new method of calculating the Mulliken net charges of the nitro group, Q(NO)()2, to assess impact sensitivities for nitro compounds is established. All calculations including optimizations and Mulliken population and frequency analyses are performed by density functional theory (DFT) and the general gradient approximation (GGA) method in Acceryls' code Dmol(3) with the Beck-LYP hybrid functional and the DNP basis set. As a result, the charges on nitro group can be regarded as a structural parameter to estimate the impact sensitivity on the bond strength, oxygen balance, and molecular electrostatic potential. The compound with more -Q(NO)()2 will be insensitive and gives a large value of impact sensitivity H(50)(). This method considering the molecular structure is applicable for almost all nitro compounds when the C-NO(2), N-NO(2), or O-NO(2) bond is the weakest in the molecule. According to the results in this paper, the compounds with -Q(NO)()2 >0.23e show H(50)()