Knowledge and Barriers About Blood Donation and Associated Factors in Saudi Arabia: A Systematic Review.

Transfusions and blood donations are relatively risk-free medical procedures. However, attitudes, beliefs, and knowledge levels about blood donation and transfusion may influence such operations. This systematic review aims to comprehensively investigate the level of knowledge and attitudes towards blood donation in Saudi Arabia. PubMed, Scopus, Web of Science, and ScienceDirect were systematically searched for relevant literature. Rayyan (Qatar Computing Research Institute, Ar-Rayyan, Qatar) was employed throughout this comprehensive process. This review included 17 studies with a total of 9,212 patients, and 4,806 (52.2%) were males. The majority of Saudis lacked awareness about blood donation and had unfavorable opinions towards it. In addition to various fears, mistrust, a lack of information, and not being approached by anyone to donate blood, participants reported that the distance to the donation site, the difficulty with transportation, the time commitment, getting a quick break from work or the office, or taking time off from home were also contributing to the negative attitudes towards blood donation. While youthful participants were more likely to contribute, Saudi university students in this study had inadequate information but positive attitudes about blood donation. Ineligibility, fear of giving blood, and inaccurate information regarding blood donation are the main deterrents to blood donation.

Enhancement of Radiation Sensitivity by Cathepsin L Suppression in Colon Carcinoma Cells.

Cancer is one of the main causes of death globally. Radiotherapy/Radiation therapy (RT) is one of the most common and effective cancer treatments. RT utilizes high-energy radiation to damage the DNA of cancer cells, leading to their death or impairing their proliferation. However, radiation resistance remains a significant challenge in cancer treatment, limiting its efficacy. Emerging evidence suggests that cathepsin L (cath L) contributes to radiation resistance through multiple mechanisms. In this study, we investigated the role of cath L, a member of the cysteine cathepsins (caths) in radiation sensitivity, and the potential reduction in radiation resistance by using the specific cath L inhibitor (Z-FY(tBu)DMK) or by knocking out cath L with CRISPR/Cas9 in colon carcinoma cells (caco-2). Cells were treated with different doses of radiation (2, 4, 6, 8, and 10), dose rate 3 Gy/min. In addition, the study conducted protein expression analysis by western blot and immunofluorescence assay, cytotoxicity MTT, and apoptosis assays. The results demonstrated that cath L was upregulated in response to radiation treatment, compared to non-irradiated cells. In addition, inhibiting or knocking out cath L led to increased radiosensitivity in contrast to the negative control group. This may indicate a reduced ability of cancer cells to recover from radiation-induced DNA damage, resulting in enhanced cell death. These findings highlight the possibility of targeting cath L as a therapeutic strategy to enhance the effectiveness of RT. Further studies are needed to elucidate the underlying molecular mechanisms and to assess the translational implications of cath L knockout in clinical settings. Ultimately, these findings may contribute to the development of novel treatment approaches for improving outcomes of RT in cancer patients.

Combining FES and Exoskeletons in a Hybrid Haptic System for Enhancing VR Experience.

Robotic technology and functional electrical stimulation (FES) have emerged as highly effective rehabilitative techniques for individuals with neuromuscular diseases, showcasting their ability to restore motor functions. Within the proposed study, we developed and tested a new hybrid controller combining an upper-limb exoskeleton with FES to enhance haptic feedback when performing task-oriented and bimanual movement, like pick-and-place, in a virtual environment. We investigated the performance of the proposed approach on eight unimpaired participants providing haptic feedback either only by the exoskeleton or by the hybrid system. The hybrid control presents two different modalities, assistive and resistive, to modulate the perception of the load. FES intensity is calibrated to the subjects' biomechanical properties and it is adjusted in real-time according to the real-time motion of the upper limbs. Experimental results highlighted the ability of the hybrid control to improve kinematic performance: in both hybrid modalities subjects reduced the target matching error(values between 0.048±0.007 m and 0.06±0.006 m) without affecting the normal motion smoothness (SPARC values in the hybrid conditions range from -2.58±0.12 to -3.30±0.13). Moreover, the resistive approach resulted in greater metabolic consumption (1.04±0.03 W/kg), indicating a more realistic experience of lifting a virtual object through FES that increased the perceived weight. The innovation in our hybrid control relies on the modulation of muscular activation during manipulation tasks, which could be a promising approach in the clinical treatment of neuromuscular diseases.

The Significance of Cathepsin B in Mediating Radiation Resistance in Colon Carcinoma Cell Line (Caco-2).

Cathepsins (Caths) are lysosomal proteases that participate in various physiological and pathological processes. Accumulating evidence suggests that caths play a multifaceted role in cancer progression and radiotherapy resistance responses. Their proteolytic activity influences the tumor's response to radiation by affecting oxygenation, nutrient availability, and immune cell infiltration within the tumor microenvironment. Cathepsin-mediated DNA repair mechanisms can promote radioresistance in cancer cells, limiting the efficacy of radiotherapy. Additionally, caths have been associated with the activation of prosurvival signaling pathways, such as PI3K/Akt and NF-κB, which can confer resistance to radiation-induced cell death. However, the effectiveness of radiotherapy can be limited by intrinsic or acquired resistance mechanisms in cancer cells. In this study, the regulation and expression of cathepsin B (cath B) in the colon carcinoma cell line (caco-2) before and after exposure to radiation were investigated. Cells were exposed to escalating ionizing radiation doses (2 Gy, 4 Gy, 6 Gy, 8 Gy, and 10 Gy). Analysis of protein expression, in vitro labeling using activity-based probes DCG04, and cath B pull-down revealed a radiation-induced up-regulation of cathepsin B in a dose-independent manner. Proteolytic inhibition of cathepsin B by cathepsin B specific inhibitor CA074 has increased the cytotoxic effect and cell death due to ionizing irradiation treatment in caco-2 cells. Similar results were also obtained after cathepsin B knockout by CRISPR CAS9. Furthermore, upon exposure to radiation treatment, the inhibition of cath B led to a significant upregulation in the expression of the proapoptotic protein BAX, while it induced a significant reduction in the expression of the antiapoptotic protein BCL-2. These results showed that cathepsin B could contribute to ionizing radiation resistance, and the abolishment of cathepsin B, either by inhibition of its proteolytic activity or expression, has increased the caco-2 cells susceptibility to ionizing irradiation.

Impact of Enniatin B and Beauvericin on Lysosomal Cathepsin B Secretion and Apoptosis Induction.

Enniatin B (ENN B) and Beauvericin (BEA) are cyclohexadepsipeptides that can be isolated from Fusarium and Beauveria bassiana, respectively. Both compounds are cytotoxic and ionophoric. In the present study, the mechanism of cell death induced by these compounds was investigated. Epidermal carcinoma-derived cell line KB-3-1 cells were treated with different concentrations of these compounds. The extracellular secretion of cathepsin B increased in a concentration-dependent manner, and the lysosomal staining by lysotracker red was reduced upon the treatment with any of the compounds. However, the extracellular secretion of cathepsin L and cathepsin D were not affected. Inhibition of cathepsin B with specific inhibitor CA074 significantly reduced the cytotoxic effect of both compounds, while inhibition of cathepsin D or cathepsin L did not influence the cytotoxic activities of both compounds. In vitro labelling of lysosomal cysteine cathepsins with Ethyl (2S, 3S)-epoxysuccinate-Leu-Tyr-Acp-Lys (Biotin)-NH2 (DCG04) was not affected in case of cathepsin L upon the treatment with both compounds, while it was significantly reduced in case of cathepsin B. In conclusion, ENN B and BEA increase lysosomal Ph, which inhibits delivery of cathepsin B from Golgi to lysosomes, thereby inducing cathepsin B release in cytosol, which activates caspases and hence the apoptotic pathway.

Sunlit photocatalytic degradation of organic pollutant by NiCr2O4/Bi2S3/Cr2S3 tracheid skeleton nanocomposite: Mechanism, pathway, reactive sites, genotoxicity and byproduct toxicity evaluation.

In this study, 3D C2S3 (CS) and 2D Bi2S3 (BS) modified NiCr2O4 nanocomposite (NCO-BS-CS NCs) was prepared by sonochemical assisted co-precipitation method for the enhanced photocatalytic activity. Here, NCO-BS-CS NCs showed band gap energy of 2.23 eV and the PL intensity of NCO-BS-CS NCs was lower than NCO, BS, and CS NPs. Thus, the results indicate the fabricated NCO-BS-CS NCs enhance the charge segregation and lower in recombination rate. NCO-BS-CS NCs showed enhanced photodegradation of methyl orange (MO) (95%) and congo red (CR) (99.7%) respectively. The total organic compound (TOC) analysis shows the complete mineralization of about 91 and 98% for MO and CR respectively. Furthermore, the Fukui function was used for the prediction of reactive sites in the photodegradation pathway of MO and CR by NCs. ECOSAR program was done to determine the toxicity of the intermediate and the results conclude that the degraded product shows nontoxic to the environmental organism (fish, daphnia, and algae). Thus, the fabricated NCO-BS-CS NCs can be used for the remediation of toxic organic pollutants from the waste water by photocatalytic degradation.

A detailed multi-omics analysis of GNB2 gene in human cancers.

The Guanine-nucleotide binding protein 2 (GNB2) encodes for ß2 subunit (Gß2) of the G-protein complex. Keeping in view the increased demand of reliable biomarkers in cancer, the current study was planned to extensively explored GNB2 expression variation and its roles in different cancers using online available databases and diverse methodology. In view of our results, the GNB2 was notably up-regulated relative to corresponding controls in twenty three cancer types. As well, the elevated expression of GNB2 was found to be associated with the reduced overall survival (OS) of the Liver Hepatocellular Carcinoma (LIHC) and Rectum Adenocarcinoma (READ) only out of all analyzed cancer types. This implies GNB2 plays vital role in the tumorigenesis of LIHC and READ. Several additional analysis also explored six critical pathways and few important correlations related to GNB2 expression and different other parameters such as promoter methylation, tumor purity, CD8+ T immune cells infiltration, and genetic alteration, and chemotherapeutic drugs. In conclusion, GNB2 gene has been identified in this study as a shared potential biomarker (diagnostic and prognostic) of LIHC and READ.

A prominent dual heterojunction framed CuWO4/Bi2WO6/MnS ternary NCs for para-chlorophenol degradation, Cr(VI) reduction & toxicity studies.

In account of environmental remediation, an ideal photocatalyst was fabricated for the effective treatment of water systems. Herein, dual heterojunctions framed CuWO4/Bi2WO6/MnS nanocomposite (NCs) was synthesized via simple co-precipitation method followed by ultra-sonicated assisted route. The prepared NCs were investigated its photocatalytic degradation performance using para-chlorophenol (4-CP) and reduction of chromium VI (Cr (VI)) under visible light irradiation. The photocatalyst were characterized by various analytical techniques including XRD, HR-TEM, XPS, UV-vis DRS, FE-SEM, EIS, PL, ESR, Raman and N2 adsorption and desorption studies. The excellent photodegradation of 4-CP was observed within 180 min by the NCs. Similarly, the Cr (VI) reduction was about 97% within 140 min. The effect of pH and influence of different dosage of NCs and 4-CP on the photodegradation efficiency was investigated. The reusability and stability of the NCs was examined over 6 consecutive runs where the XRD and XPS confirm the structural stability of the prepared NCs. The scavenging experiment were carried out to elucidate the mechanism and the active species involved were O2-• and OH• radicals. The TOC analysis affirmed the complete mineralization of the prepared NCs. The ecotoxicity analysis was carried out to determine the toxicity effect of intermediates using ECOSAR software and the end product toxicity was also evaluated against E. coli and S. epidermis. The end product toxicity study also confirmed that the degraded product was less toxic compared to parent compound. Further, the genotoxicity study was done to understand the environmental impact using allium cepa and results confirms that there are no causes of cytotoxicity & genotoxicity by the prepared NCs. Therefore, the prepared NCs can be economical, efficient with excellent photocatalytic performance and environment friendly.

Sunlit expeditious visible light-mediated photo-fenton degradation of ciprofloxacin by exfoliation of NiCo2O4 and Zn0·3Fe2·7O4 over g-C3N4 matrix: A brief insight on degradation mechanism, degraded product toxicity, and genotoxic evaluation in Allium cepa.

Pharmaceutical pollutant in the environmental water bodies has become a major concern, which causes adverse effect to aquatic entities. This study provides an incisive insight on the photocatalytic degradation of ciprofloxacin (CIP) and the development of rationally engineered g-C3N4-NiCo2O4-Zn0.3Fe2·7O4 nanocomposite for boosted photocatalytic performance under visible light irradiation. The g-C3N4-NiCo2O4-Zn0.3Fe2·7O4 nanocomposite was synthesized via ultrasonication-assisted hydrothermal method. The characterization of the as-prepared material was evaluated by XPS, SEM, HR-TEM, PL, FT-IR, EIS, ESR, XRD, BET, and UV-Vis DRS techniques. Furthermore, the effect of catalytic dosage, drug dosage, and pH changes was explored, where g-C3N4-NiCo2O4-Zn0.3Fe2·7O4-10% unveiled excellent visible light photo-Fenton degradation of 92% for CIP at 140 min. The hydroxyl radicals (OH.) served as the predominant radical species on the photodegradation of CIP, which was confirmed by performing a radical scavenging test. Furthermore, the degradation efficiency was determined by six consecutive cycle tests, where the nanomaterial exhibited excellent stability with 98.5% reusable efficiency. The degradation of CIP was further scrutinized by GC-MS analysis, where the degraded intermediate products and the possible pathway were elucidated. The degraded product toxicity was determined by ECOSAR program, where the degraded products haven't exhibited any considerable toxic effects. In addition, the genotoxicity of the nanomaterial was determined by treating them with root tips of A. cepa, where it was found to be non-toxic. Here, the prepared g-C3N4-NiCo2O4-Zn0.3Fe2·7O4 nanocomposite (CNZ NCs) shows eco-friendly and excellent photo-Fenton activity for environmental applications.

Plasma-assisted in-situ preparation of L-cystine functionalized silver nanoparticle: An intelligent multicolor nano-sensing of cadmium and paracetamol from environmental sample.

L-cystine (L-cys) functionalized plasmonic silver nanomaterial (Ag NPs) was fabricated toward the selective and sensitive detection of paracetamol and cadmium. The prepared L-cys-Ag nanoparticles (NPs) were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and fourier transform infrared spectroscopy (FTIR) analyses. SEM imaging show that Ag NPs was decorated on the surface of L-cysteine 3D cubic nanosheet. L-cys-Ag NPs showed selective and sensitive detection towards paracetamol and cadmium. The interference study confirms that the presence of other metal ions didn't inhibit the detection of cadmium by L-cys-Ag NPs. The limit of detection of paracetamol and cadmium by L-cys-Ag NPs was calculated to be 1.2 and 2.82 nM respectively. In addition, the real sample detection of paracetamol on blood serum and urine, and cadmium on STP were performed and the recovery percentage was above 97%. Further, the real sample analysis was performed in tap and drinking water and the recovery percentage was more than 98%. The analytic logic gate on the multicolour detection of cadmium and paracetamol was performed for the semi-quantitative monitoring of paracetamol and cadmium by L-cys-Ag NPs. The developed L-cys-Ag NPs were found to be an effective tool for the monitoring of cadmium in environmental water bodies and paracetamol in blood and urine.

Engineering silicon-carbide quantum dots for third generation photovoltaic cells.

Interested in the recent development of the building up of photovoltaic devices using graphene-like quantum dots as a novel electron acceptor; we study in this work the optoelectronic properties of edge-functionalized SiC quantum dots using the first principles density functional. For an accurate quantitative estimation of key parameters, a many-body perturbation theory within GW approximation is also performmed. We examine the ability to tailor the electronic gap and optical absorption of the new class of QDs through hydroxylation and carboxylation of seam atoms, in order to improve their photovoltaic efficiency. The HOMO-LUMO energy gap was significantly altered in terms of the type, the concentration and the position of functional groups. The spatial charge separation and charge transfer characterizing our systems seem very prominent to use as dye-sensitized solar cells. Furthermore, the optical band gap of all our compounds is in the NIR-visible energy window, and exhibits a magnitude smaller than that calculated in the pristine case, which enhances the photovoltaic efficiency. Likewise, absorption curves, exciton binding energy and singlet-triplet energy splitting have been broadly modified by functionalization confirming the great luminescent yield of SiCQDs. Depending on the size, SiC quantum dots absorb light from the visible to the near-infrared region of the solar spectrum, making them suitable for third generation solar cells.

Graphene and silicene quantum dots for nanomedical diagnostics.

In the present work, the prominent effects of edge functionalization, size variation and base material on the structural, electronic and optical properties of diamond shaped graphene and silicene quantum dots are investigated. Three functional groups, namely (-CH3, -OH and -COOH) are investigated using the first principles calculations based on the density functional, time-dependent density functional and many-body perturbation theories. Both the HOMO-LUMO energy gap, the optical absorption and the photoluminescence are clearly modulated upon functionalization compared to the H-passivated counterparts. Besides the functional group, the geometric distortion induced in some QDs also influences their optical features ranging from near ultra-violet to near infra-red. All these results indicate that edge-functionalizations provide a favorable key factor for adjusting the optoelectronic properties of quantum dots for a wide variety of nanomedical applications, including in vitro and in vivo bioimaging in medical diagnostics and therapy.

New highly efficient 2D SiC UV-absorbing material with plasmonic light trapping.

The present paper is a systematic analysis of the thermoelectric and optical properties of the SiC monolayer. Based on the density functional theory (DFT) combined with the Boltzmann transport theory, the thermal conductivity, the electrical conductivity and the figures of merit are all determined and discussed for the SiC hybrid. At room temperature, it is found that SiC shows interesting values with respect to its counterparts graphene and silicene. To improve the absorption of the SiC sheet, a strategy is proposed using finite-difference time-domain (FDTD) combing with PSO-based approach. The absorbance of the UV-photodector with SiC monolayer and the SiC-based photodector with Au plasmonic grating are studied. Among our findings, the Au plasmonic grating enhances the absorbance of SiC to reach a maximum absorbance of 99.6% at the resonance wavelength of ([Formula: see text] nm), which significantly improves the performance of UV-sensors. Therefore, by combining optical DFT analysis with FDTD simulation supported by global PSO optimization, we have been able to develop a new SiC monolayer high performance UV photodetector suitable for advanced optoelectronic applications.

Size engineering optoelectronic features of C, Si and CSi hybrid diamond-shaped quantum dots.

Based on the density functional theory and many-body ab initio calculations, we investigate the optoelectronic properties of diamond-shaped quantum dots based graphene, silicene and graphene-silicene hybrid. The HOMO-LUMO (H-L) energy gap, the exciton binding energy, the singlet-triplet energy splitting and the electron-hole overlap are all determined and discussed. Smaller nanostructures show high chemical stability and strong quantum confinement resulting in a significant increase in H-L gap and exciton binding energy. On the other hand, the larger configurations are reactive which implies characteristics favorable to possible electronic transport and conductivity. In addition, the typically strong splitting between singlet and triplet excitonic states and the big electron-hole overlap make these QDs emergent systems for nanomedicine applications.

Tuning Optoelectronic Properties of the Graphene-Based Quantum Dots C16- xSi xH10 Family.

The electronic and optical properties of graphene-based quantum dots (QDs) are investigated using DFT and many-body perturbation theory. Formation energy, hardeness and electrophilicity show that all structures, from pyrene to silicene QD passing through 15 CSi QD configurations, are energetically and chemically stable. It is also found that they are reactive which implies their favorable character for the possible electronic transport and conductivity. The electronic and optical properties are very sensitive to the number and position of the substituted silicon atoms as well as the directions of the light polarization. Moreover, quantum confinement effects make the exciton binding energy of CSi quantum dots larger than those of their higher dimensional allotropes such as silicene, graphene, and SiC sheet and nanotube. It is also higher those of other shapes of quantum dots like hexagonal graphene QDs and can be tailored from the ultraviolet region to the visible one. The values of the singlet-triplet splitting determined for the X- and Y-light polarized indicate that all configurations have a high fluorescence quantum yield compared to the yield of typical semiconductors, which makes them very promising for various applications such as the light-emitting diode material and nanomedicine.

Halogenation of SiC for band-gap engineering and excitonic functionalization.

The optical excitation spectra and excitonic resonances are investigated in systematically functionalized SiC with Fluorine and/or Chlorine utilizing density functional theory in combination with many-body perturbation theory. The latter is required for a realistic description of the energy band-gaps as well as for the theoretical realization of excitons. Structural, electronic and optical properties are scrutinized and show the high stability of the predicted two-dimensional materials. Their realization in laboratory is thus possible. Large band-gaps of the order of 4 eV are found in the so-called GW approximation, with the occurrence of bright excitons, optically active in the four investigated materials. Their binding energies vary from 0.9 eV to 1.75 eV depending on the decoration choice and in one case, a dark exciton is foreseen to exist in the fully chlorinated SiC. The wide variety of opto-electronic properties suggest halogenated SiC as interesting materials with potential not only for solar cell applications, anti-reflection coatings or high-reflective systems but also for a possible realization of excitonic Bose-Einstein condensation.

Clinical factors associated with hyperkalemia in patients with congestive heart failure.

BACKGROUND: Patients with congestive heart failure (CHF) are at risk for hyperkalemia because of coexisting comorbidities and use of multiple medications that impair potassium (K) excretion such as angiotensin converting enzyme (ACE) inhibitors. OBJECTIVE: To identify clinical factors associated with hyperkalemia on initial presentation in patients hospitalized for CHF. DESIGN: A case-control study. SETTING: Two university-affiliated tertiary-care hospitals. SUBJECTS: Using ICD-9 code for CHF, CHF admissions with hyperkalemia on presentation (cases) were identified from a population of 938 non-dialysis-dependent CHF patients. CHF admissions with normokalemia on presentation were used as controls. Hyperkalemia was defined as serum K > or = 5.6 mmol/L, and normokalemia as serum K > or = 3.5 and < or =5.5. METHODS: Data were collected on demographic characteristics, clinical variables, comorbidity and medication use. Factors associated with hyperkalemia on initial presentation were examined. RESULTS: Mean age did not differ between cases [76 years, standard deviation (SD) = 12] and controls (75 years, SD = 12) (P = 0.824). Mean potassium levels for cases and controls were 6.2 mmol/L (range 5.6 to 8.2) and 4.3 mmol/L respectively (P < 0.001). On multivariate analysis, diabetes mellitus [odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.04-5.59], creatinine clearance <40 mL/min (OR = 8.36, CI = 2.73-25.56), use of spironolactone (OR = 4.18, CI = 1.27-13.79), and use of ACE inhibitors (OR = 2.55, CI = 1.06-6.13) were independently associated with hyperkalemia. CONCLUSIONS: In CHF patients, hyperkalemia on presentation is independently associated with diabetes, creatinine clearance <40 mL/min, use of spironolactone, and use of ACE inhibitors. Recommendations for use of spironolactone and ACE inhibitors in CHF, and the intensity of serum K monitoring need to be clarified to account for patients at higher risk for hyperkalemia.

Antibiotic use, hospital admissions, and mortality before and after implementing guidelines for nursing home-acquired pneumonia.

OBJECTIVES: To compare two strategies for implementing guidelines for nursing home-acquired pneumonia (NHAP) and to measure outcomes associated with treatment in accordance with the guidelines. DESIGN: Randomized controlled trial. SETTING: Ten skilled nursing facilities (SNFs) from a single metropolitan area. PARTICIPANTS: Patients with an episode of pneumonia acquired more than 3 days after admission to SNF (N = 350): 226 preintervention episodes of pneumonia and 116 postintervention episodes. INTERVENTIONS: Multi-faceted education intervention including small-group consensus process limited to physicians and a similar intervention that included physicians and nurses within randomly selected SNFs. MEASUREMENTS: Antibiotic use at diagnosis compared with the guidelines, hospital admission, severity of pneumonia, and 30-day mortality. RESULTS: Data were complete for 344 episodes of NHAP. For the preintervention group (n = 226), 62.2% (79/127) of the episodes were treated with parenteral antibiotics (PA) when PA were recommended by the guidelines and 57.6% (57/99) of episodes were treated with oral antibiotics (OA) when OA were indicated by the guidelines. Postintervention, treatment with PA and OA according to the guidelines was not significantly different between the two groups of randomized SNFs. A multivariate analysis comparing PA use pre- and postintervention for all SNFs, adjusted for variation in the frequency and severity of pneumonia, found significantly more of the postintervention episodes were treated with PA in accordance with the guidelines (P < .02). A preintervention significant difference in 30-day mortality observed between episodes with indications for PA (37.8% (48/127)) and episodes with indications for OA (6.1% (6/99)) (P < .001) was not present postintervention (11.5% (6/52); (23.8% (15/64); P = .06). There was no significant difference in 30-day mortality preintervention and postintervention for episodes with guideline indications for OA (P = .35) or for PA (P = .05) (P = .16 for multivariate analysis). The difference in PA use was not associated with significant differences in hospital admissions for episodes on NHAP. CONCLUSION: The increase in the use of PA provides evidence that care within SNFs can be significantly changed using standard quality improvement techniques. Use of the guidelines did not significantly affect mortality. The addition of a practical severity of NHAP model or a change in reimbursement structure may enhance the guidelines' impact on hospitalization for NHAP. The financial benefits available with use of the guidelines will be limited unless the guidelines contribute to a reduction in rates of hospitalization.

Etiology of severe pneumonia in the very elderly.

The etiology of severe pneumonia requiring mechanical ventilation in the very elderly has been imprecise because of lack of comprehensive studies and low yield of diagnostic approach. Overall, 104 patients 75 yr of age and older with severe pneumonia were studied prospectively at two university-affiliated hospitals. Microbial investigation included blood culture, serology, pleural fluid, and bronchoalveolar secretions. Streptococcus pneumoniae (14%), gram-negative enteric bacilli (14%), Legionella sp. (9%), Hemophilus influenzae (7%), and Staphylococcus aureus (7%) were the predominant pathogens in community-acquired pneumonia (CAP). Staphylococcus aureus (29%), gram-negative enteric bacilli (15%), Streptococcus pneumoniae (9%), and Pseudomonas aeruginosa (4%) accounted for most isolates of nursing home-acquired pneumonia (NHAP). The case fatality rate was 55% (53% for CAP and 57% for NHAP; p > 0.5). Activity of Daily Living (ADL) Index, pulmonary, endocrine and central nervous system (CNS) comorbidities were associated with distinct microbial etiology. By multivariate analysis, hospital mortality was associated independently with 24-h urine output (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.5 to 7.9; p < 0.001), septic shock (OR, 4.3; 95% CI, 1.9 to 8.9; p = 0.0059), radiographic multilobar involvement (OR, 3.7; 95% CI, 1.8 to 15.6; p = 0.02), and inadequate antimicrobial therapy (OR, 2.6; 95% CI, 1.4 to 23.9; p = 0.034). Further studies should focus on identifying effective antimicrobial regimens in randomized trials.

Outcome of older patients with severe pneumonia predicted by recursive partitioning.

OBJECTIVES: To develop a prognostic model to predict outcome of older patients with severe pneumonia requiring mechanical ventilation. DESIGN: A nonconcurrent prospective study. SETTING: A 24-bed intensive care unit (ICU) within two university-affiliated tertiary care hospitals. PARTICIPANTS: All patients age 75 and older with severe pneumonia between June 1996 and September 1999 were included. Demographic data including activities of daily living (ADL) index score before admission, and clinical and laboratory data were collected in the first 24 hours of admission to the ICU. One hundred four patients (mean age +/- standard deviation (SD) 82.3 +/- 5.5 years) met the inclusion criteria. MEASUREMENTS: A classification tree was developed using binary recursive partitioning to predict hospital discharge. The model was compared with a logistic regression model using variables selected by the tree analysis and with the Acute Physiologic and Chronic Health Evaluation (APACHE) II. RESULTS: Outcome predictors for the classification tree were use of vasopressors, presence of multilobar pneumonia on chest radiograph, ratio of blood urea nitrogen to creatinine, Glasgow Coma Scale, urine output, and ADL score before admission. The tree achieved a sensitivity of 83.8% (95% confidence interval (CI) 69.2-92.4) and a specificity of 93.3% (95% CI 83-98.1). The predictive accuracy as assessed by the area under the curve (c-index +/- standard error) was significantly higher with the classification tree (0.932 +/- 0.03) than with logistic regression and APACHE II, (0.801 +/- 0.028 and 0.711 +/- 0.049, respectively (P < .05). CONCLUSIONS: The classification tree model demonstrated a superior predictive accuracy to that of logistic regression and APACHE II. If validated prospectively, the classification tree can be used as a tool to assess the outcome of older patients with severe pneumonia requiring mechanical ventilation on admission to the ICU. In addition, the classification tree can be used to assist healthcare workers in providing a concise summary of local outcome experience and prognostic information to patients and their surrogates.