ABSTRACT
Methods@#Patients undergoing elective PCDF at our urban academic medical center from 2014 to 2020 were included. Patients were categorized by mFI scores (0–0.08, 0.09–0.17, 0.18–0.26, and ≥0.27). Univariate statistics compared demographics, comorbidities, and clinical/surgical outcomes. Multiple linear regression analysis evaluated the magnitude of improvement in PROMs at 1 year. @*Results@#A total of 165 patients were included and grouped by mFI scores: 0 (n=36), 0.09 (n=62), 0.18 (n=42), and ≥0.27 (n=30). The severe frailty group (mFI ≥0.27) was significantly more likely to be diabetic (p <0.001) and have a greater Elixhauser comorbidity index (p =0.001). They also had worse baseline Physical Component Score-12 (PCS-12) (p =0.011) and modified Japanese Orthopaedic Association (mJOA) (p =0.012) scores and worse 1-year postoperative PCS-12 (p =0.008) and mJOA (p =0.001) scores. On regression analysis, an mFI score of 0.18 was an independent predictor of greater improvement in ΔVisual Analog Scale neck (β =−2.26, p =0.022) and ΔVAS arm (β =−1.76, p =0.042). Regardless of frailty status, patients had similar 90-day readmission rates (p =0.752), complication rates (p =0.223), and revision rates (p =0.814), but patients with severe frailty were more likely to have longer hospital length of stay (p =0.006) and require non-home discharge (p <0.001). @*Conclusions@#Similar improvements across most PROMs can be expected irrespective of the frailty status of patients undergoing PCDF. Complication rates, 90-day readmission rates, and revision rates are not significantly different when stratified by frailty status. However, patients with severe frailty are more likely to have longer hospital stays and require non-home discharge.
ABSTRACT
Biocover systems are a cost-effective technology utilised to mitigate methane (CH4) and trace gas emissions from landfills. A full-scale biofilter system was constructed at Glatved landfill, Denmark, consisting of three biofilters with a total area of 3950 m2. Landfill gas collected mainly from shredder waste cells was mixed with ambient air and fed actively into the biofilter, resulting in an average load of 60-75 g m-2 d-1 for CH4 and 0.15-0.21 g m-2 d-1 for trace gases (e.g., aromatics, chlorofluorocarbons (CFCs), aliphatic hydrocarbons). The initial CH4 surface screening showed uneven gas distribution into the system, and elevated surface concentrations were observed close to the gas inlet. Both positive and negative CH4 fluxes, ranging from -0.36 to 4.25 g m-2 d-1, were measured across the surface of the biofilter. Total trace gas emissions were between -0.005 and 0.042 g m-2 d-1, and the emission flux of individual compounds were generally small (10-8 to 10-3 g m-2 d-1). Vertical gas concentration profiles showed that the oxidation of CH4 and easily degradable trace compounds such as aromatics and aliphatic hydrocarbons happened in the aerobic zones, while CFCs were degraded in the anaerobic zone inside the compost layer. In addition, oxidation/degradation of CH4 and trace gases also occurred in the gas distribution layer, which contributed significantly to the overall mitigation efficiency of the biofilter system. Overall, the biofilter system showed mitigation efficiencies of nearly 100% for both CH4 and trace gases, and it might have the potential to work under higher loads.
