Understanding of pulmonary mechanics is essential to understanding mechanical ventilation. Typically, clinicians are mindful of peak and plateau pressures displayed on the ventilator and lung compliance, which is decreased in lung disease such as idiopathic pulmonary fibrosis (IPF). Decreased lung compliance leads to elevated peak and plateau pressures. We present a patient with IPF undergoing mechanical ventilation after cardiac arrest. Despite low lung compliance, he had normal peak and plateau pressures due to the presence of flail chest and increased chest wall compliance. This case highlights the role chest wall compliance plays in total respiratory system compliance and pulmonary mechanics.

Rationale: Coronavirus Disease 2019 (COVID-19) is a highly contagious respiratory viral illness causing pneumonia and systemic disease. Abnormalities in pulmonary function after COVID-19 infection have been described. The determinants of these abnormalities are unclear. We hypothesized that inflammatory biomarkers and computed tomography (CT) scan parameters at the time of infection would be associated with abnormal gas exchange at short term follow-up.Methods: We studied subjects who were hospitalized for COVID-19 pneumonia and then discharged. Those with pre-existing lung disease (except asthma) or reduced diffusing capacity for carbon monoxide (DLCO) prior to COVID-19 infection were excluded. Information on serum inflammatory biomarkers, CT scan, and clinical characteristics were collected in the index hospitalization. Pulmonary function tests and 6-minute walk tests were assessed at 2-3 months after discharge. CT images at the time of hospitalization were evaluated by Functional Respiratory Imaging (FRI;FLUIDDA, Inc., Antwerp, Belgium) with 3D reconstruction of the lungs and pulmonary vasculature to analyze pulmonary blood volume. Blood volumes of the pulmonary vessels that were ≤5mm (BV5), 5-10mm (BV5-10), and ≥10mm (BV10) in cross-sectional area were analyzed. Additionally, the amount of inflammation on CT (ground-glass opacities) was quantified. We divided subjects into those with a DLCO <80% predicted and those with a DLCO ≥80% predicted based on follow-up pulmonary function tests. Results: 38 subjects were included in our cohort. Pulmonary function tests were performed 76.5±35.1 days after the first day of hospitalization. The results are summarized in the Table. 31 out of 38 (81.5%) subjects had a DLCO<80% predicted. The groups were similar in terms of demographics, body mass index, and smoking status. Peak D-dimer, LDH, and ferritin levels were greater in the DLCO<80% group. Spirometric measures and lung volumes were similar between groups. Inflammation was not different between groups, but BV5-10 and BV10 measures were higher in the DLCO<80% group. BV5-10 was associated with DLCO<80% in multivariable logistic regression with demographics, smoking status, lung volumes, and hemoglobin as covariates (OR 1.29, 95% CI 1.01, 1.64).Conclusions: Higher peak D-dimer levels at the time of hospitalization and abnormalities in pulmonary blood volumes are associated with a reduced DLCO at follow-up. These findings suggest that pulmonary vascular and coagulation abnormalities during hospitalization with COVID-19 might have long-lasting effects on pulmonary function. Further study regarding the influence of pulmonary blood volumes and measures of abnormal coagulation on short term COVID-19 outcomes is warranted.

Background Coronavirus Disease 2019 (COVID-19) is a respiratory viral illness causing pneumonia and systemic disease. Abnormalities in pulmonary function tests (PFT) after COVID-19 infection have been described. The determinants of these abnormalities are unclear. We hypothesized that inflammatory biomarkers and CT scan parameters at the time of infection would be associated with abnormal gas transfer at short term follow-up. Methods We retrospectively studied subjects who were hospitalized for COVID-19 pneumonia and discharged. Serum inflammatory biomarkers, CT scan and clinical characteristics were assessed. CT images were evaluated by Functional Respiratory Imaging with automated tissue segmentation algorithms of the lungs and pulmonary vasculature. Volumes of the pulmonary vessels that were ≤5mm (BV5), 5-10mm (BV5_10), and ≥10mm (BV10) in cross sectional area were analyzed. Also the amount of opacification on CT (ground glass opacities). PFT were performed 2–3 months after discharge. The diffusion capacity of carbon monoxide (DLCO) was obtained. We divided subjects into those with a DLCO <80% predicted (Low DLCO) and those with a DLCO ≥80% predicted (Normal DLCO). Results 38 subjects were included in our cohort. 31 out of 38 (81.6%) subjects had a DLCO<80% predicted. The groups were similar in terms of demographics, body mass index, comorbidities, and smoking status. Hemoglobin, inflammatory biomarkers, spirometry and lung volumes were similar between groups. CT opacification and BV5 were not different between groups, but both Low and Normal DLCO groups had lower BV5 measures compared to healthy controls. BV5_10 and BV10 measures were higher in the Low DLCO group compared to the normal DLCO group. Both BV5_10 and BV10 in the Low DLCO group were greater compared to healthy controls. BV5_10 was independently associated with DLCO<80% in multivariable logistic regression (OR 1.29, 95% CI 1.01, 1.64). BV10 negatively correlated with DLCO% predicted (r = -0.343, p = 0.035). Conclusions Abnormalities in pulmonary vascular volumes at the time of hospitalization are independently associated with a low DLCO at follow-up. There was no relationship between inflammatory biomarkers during hospitalization and DLCO. Pulmonary vascular abnormalities during hospitalization for COVID-19 may serve as a biomarker for abnormal gas transfer after COVID-19 pneumonia.

Introduction: The “obesity paradox” has been reported in critically ill patients with acute respiratory distress syndrome (ARDS). Obese patients with ARDS were shown to have more ventilator free days and lower mortality compared to non-obese patients. One proposed explanation was increased levels of pro-inflammatory cytokines creating a protective environment from acute inflammation. In COVID-19, BMI ≥ 30 increases risk of illness severity, need for critical care, respiratory failure requiring use of invasive mechanical ventilation (IMV), and mortality. It is unknown if the “obesity paradox” applies to patients with SARS-CoV2 who require IMV. We examined a cohort of patients with respiratory failure due to COVID-19 who required IMV and compared outcomes between obese and non-obese patients. Methods: Data was collected from patients treated in the COVID Intensive Care Unit (ICU) from March to June 2020. A total of 85 patients were identified. All patients were COVID nasopharyngeal swab positive. Results: There were 38 (44.7%) patients with BMI < 30, and 47 (55.3%) with BMI ≥ 30. The median BMI was 25.5 in the BMI < 30 group, and 37.5 in the BMI ≥ 30 group. In the BMI < 30 group, median age was 67 years, majority male (65.8%) and African American (50%). The BMI ≥ 30 group had a median age of 63.5, majority male (53.2%) and African American (63.8%). Median Sequential Organ Failure Assessment score on admission was higher in the BMI ≥ 30 group at 3 (1.5-4.5) vs. 2 (1.0-4.0). There was elevated creatinine on admission with higher percentage of diabetes, heart failure, and renal disease in the BMI ≥ 30 group. Inflammatory markers, such as CRP and IL-6 were lower in the higher BMI group at presentation. There was higher in-hospital mortality in the BMI ≥ 30 group at 57.5%, with longer ICU length of stay (12.35 vs. 7.6 days), longer days on ventilator (10.2 vs. 4 days), and lower PaO2/FiO2 ratio after intubation (146 vs 348). The higher BMI group had higher rates of prone ventilation, paralytic use, and extracorporeal membrane oxygenation support. Discussion: From our data, obesity did not appear to have better outcomes in ARDS due to COVID-19 infection. Higher BMI was associated with higher disease severity, severe respiratory failure, longer ventilator days, longer ICU length of stay, and higher mortality. Interestingly, inflammatory markers were initially lower in obese patients, suggesting a possible adaptive physiologic response to inflammation, but without effect on overall outcomes.

PURPOSE:Severe acute respiratory syndrome coronavirus 2 (SARS-COV2) is the virus responsible for the coronavirus disease 2019 (COVID-19) which has caused a pandemic generating over half a million deaths in the United States.Lymphopenia is common at presentation in COVID-19 and has been associated with disease severity.Furthermore, patients with severe infection are more likely to have multifocal, bilateral, peripheral ground glass opacities on chest computerized tomography (CT).COVID-19 is diagnosed with a polymerase chain reaction (PCR) test using a nasopharyngeal swab (NPS) for SARS-COV2.The turnaround time for this test has improved; however, as the pandemic continues there have been shortages of reagents leading to continued challenges in timely testing.The aim of our study is to evaluate whether CT chest findings combined with absolute lymphocyte count (ALC) can predict positive COVID-19 PCR swab result. METHODS:We included 3544 patients who presented to the emergency department at a large, urban academic center between March and September 2020.All patients had a NPS for the presence of SARS-CoV-2 using the Luminex NxTAG CoV Extended Panel, a low-resolution chest CT scan without contrast, and a complete blood count with differential to determine ALC.CT scans were classified into three standardized categories by a board-certified chest radiologist based on features of multifocal pneumonia.Category 1 is consistent with multifocal pneumonia, category 2 is indeterminate for multifocal penumonia, and category 3 is inconsistent with multifocal pneumonia.In our analysis we combined categories 2 and 3 into one group.Using the Youden index (J) method, a joint test was performed on CT scan and lymphocyte count.Logistic regression was used determine the parameters of our model. RESULTS:We found that patients with category 1 CT scans and ALC < 1.6 K/mm^3 compared to patients with category 2 and 3 CT scans were 17 times more likely to have a positive NPS (Odds Ratio 17.5, Confidence Interval 14.2-21.6).Additionally, the odds ratio of a positive NPS was still 9 times greater in patients with CT scan Category 1 compared to those with categories 2 and 3 when the lymphocyte count was less than 1.6 K/mm^3 (Odds Ratio 9.2, Confidence Interval 6.8-12.5). CONCLUSIONS:Our model demonstrates that lymphopenia, defined as an ALC less than 1.6 K/mm^3, and CT scan with peripheral ground glass opacities predict a high likelihood of a positive COVID-19 swab.CLINICAL IMPLICATIONS: CT chest with multifocal pneumonia and ALC <1.6 K/mm^3 can be used as a surrogate marker for positive SARS-COV2 PCR and expedite triage decisions for patients before obtaining the results of SARS-CoV2 PCR.

PURPOSE: SARS-CoV-2 is a highly contagious respiratory virus associated with significant morbidity and mortality in the acute phase.It is also associated with long-term morbidity in a subset of patients.It is not clear which patients will have persistent symptoms.SARS-CoV-2 affects the pulmonary vasculature.We hypothesize that differences in blood volume measurements on CT of the chest during the acute phase are associated with significant dyspnea after the acute phase. METHODS:We retrospectively studied subjects hospitalized for COVID-19 pneumonia who had an initial and follow-up CT chest, pulmonary function tests (PFTs), 6-minute walk test (6MWT), and a clinical assessment in our post-COVID-19 clinic.We excluded subjects with pre-existing lung disease based on prior PFTs.Serum inflammatory biomarkers, CT scan, and clinical characteristics were assessed during the hospitalization.CT images were evaluated by Functional Respiratory Imaging (deep learning trained) with automated tissue segmentation algorithms of the lungs and pulmonary vasculature.Volumes of the pulmonary vessels that were #5mm2 (BV5), 5-10mm2 (BV5_10), and $10mm2 (BV10) in cross-sectional area were analyzed.Additionally, the amount of opacification on CT (i.e., ground-glass opacities, crazy paving, reticular disease and edema) was quantified in each patient.PFTs were performed <3 months after discharge.We defined a modified Medical Research Council (mMRC) score$2 as having significant dyspnea.We compared subjects with an mMRC score$2 to those with an mMRC score<2.BV measures were also compared to a historical cohort of healthy controls.RESULTS: 50 subjects were included.22 had mMRC score$2.The groups had similar baseline characteristics.Admission hemoglobin, peak inflammatory biomarkers, and follow-up PFTs were similar between groups.On 6MWT, there were no differences between groups in resting SpO2, lowest SpO2, or walk distance.On admission CT, percent BV5 was lower, and percents BV5_10 and BV10 were higher in the mMRC$2 group compared to the mMRC<2 group.All BV measures in both groups were different compared to healthy controls.At follow-up, BV5 measures in the mMRC$2 group improved but remained abnormal compared to healthy controls, without a statistical difference compared to the mMRC<2 group.Opacification was similar between groups on admission and follow-up CTs.CONCLUSIONS: Despite similar baseline characteristics, lung function, degree of opacification and oxygenation, persistent dyspnea after COVID-19 pneumonia is related to pruning of the small pulmonary vessels (BV5) during the acute phase and not to differences in vascular abnormalities seen in short term follow-up.CLINICAL IMPLICATIONS: Identification of markers of persistent dyspnea in post-acute COVID-19 contributes to a better understanding of the natural course and prognosis of the disease.This will impact research and patient care in the near future.

Coronavirus disease 2019 (COVID-19) is associated with a range of presentations, from milder symptoms to severe hypoxic respiratory failure, often meeting criteria for ARDS. Patients admitted to an ICU are likely to require mechanical ventilation (up to 85% in US cohorts), which is associated with increased morbidity and mortality.1Bhatraju P.K. Ghassemieh B.J. Nichols M. et al.Covid-19 in critically ill patients in the Seattle region: case series.N Engl J Med. 2020; 382: 2012-2022Crossref PubMed Scopus (1797) Google Scholar,2Richardson S. Hirsch J.S. Narasimhan M. et al.Presenting characteristics, comorbidities, and outcomes among 5700 patients hospitalized with COVID-19 in the New York City area.JAMA. 2020; 323: 2052-2059Crossref PubMed Scopus (6379) Google Scholar The near universal approach to early mechanical ventilation at the onset of the COVID-19 pandemic was driven by early data from China describing rapid deterioration with severe hypoxia, fears of patient self-induced lung injury and infection control measures because of concern about aerosolization in non-intubated patients. There remains a paucity of literature describing respiratory mechanics, ventilatory parameters, and outcomes in relation to early and late intubation in COVID-19 patients. We report the ventilatory parameters and lung mechanics of consecutive early and late intubated and ventilated patients with COVID-19 ARDS by descriptive analysis at a single urban academic center in Philadelphia, Pennsylvania. This retrospective study includes adult inpatients requiring invasive mechanical ventilation secondary to COVID-19 at Temple University Hospital between February and May 2020. Positive infection status was confirmed by polymerase chain reaction nasopharyngeal swab. The study was derived from the institutional review board (IRB)-approved Temple University Registry for COVID-19 (TUIRB Protocol Number: 26854). Subsequently, a separate IRB approval was granted for chart review to extract ventilator settings (TUIRB protocol number: 27051). Data were collected from the electronic medical record and managed using REDCap electronic data capture tools from the Temple University Hospital COVID-19 Registry.3Harris P.A. Taylor R. Thielke R. Payne J. Gonzalez N. Conde J.G. Research electronic data capture (REDCap): A metadata-driven methodology and workflow process for providing translational research informatics support.J Biomed Inform. 2009; 42: 377-381Crossref PubMed Scopus (29101) Google Scholar All patients met Berlin criteria for ARDS. Patients required invasive mechanical ventilation for acute hypoxic respiratory failure based on the Pao2/Fio2 ratio, or by clinical decision. Lung protective ventilation strategies and adjunct therapies were employed per general guidelines and physician discretion. Daily recorded ventilator parameters were analyzed. Individual patient lung compliance, driving pressures, and ventilatory ratios (VR) were calculated.4Sinha P. Fauvel N.J. Singh P. Soni N. Analysis of ventilatory ratio as a novel method to monitor ventilatory adequacy at the bedside.Crit Care. 2013; 17: R34Crossref PubMed Scopus (22) Google Scholar Descriptive statistics, either in mean with SD or median with interquartile range (IQR) and percentages, were used to present clinical data. Significance testing between groups was done with Student t test or Wilcoxon rank sum with continuous data or χ2 with categorical data. Seventy-five patients with nasopharyngeal swab-confirmed COVID-19 required invasive mechanical ventilation at Temple University Hospital during the study period. Average age was 65 years, and median BMI was 31.8. Fifty-eight percent of the patients were male, and 63% were African American. Median time to intubation was 1.27 days from presentation. Patients were separated into an early intubation (≤1.27 days) or late intubation (>1.27 days) group for analysis. Patients in the late intubation group had a lower Fio2 requirement on admission (55% vs 69%; P = .109), but a worse Pao2/Fio2 ratio (median, 160 vs 205; P = .46), higher PEEP (11.29 vs 9.30; P = .027), plateau (26.41 vs 22.50; P = .027), and peak pressures (32.21 vs 28.62; P = .044) at time of intubation in comparison with the early intubation group. Lower static compliance (34.88 vs 40.68; P = .311) and higher VR (1.90 vs 1.57; P = .078) was noted in the late intubation group on day 0, although these values were not statistically significant. Static compliance increased by day 6 of intubation in the late group, whereas it decreased in those intubated early (39.80 vs 31.66; P = .129). The late intubation group did have a significantly longer length of stay in the ICU (median, 12.31 vs 7.38 days; P = .001) and duration of mechanical ventilation (10.30 vs 5.86; P = .102) (Table 1).Table 1Patient Characteristics, Respiratory Support and Parameters, Ventilatory Parameters, and Outcomes in Early vs Late Intubation for Coronavirus Disease 2019 ARDSVariableNo. MissingTime to Intubationχ2 or t TestP ValueTotal (N = 75)Early (<1.27)(n = 37)Late (≥1.27)(n = 38)Age, No.0753738.575 Mean (SD)64.97 (14.27)65.92 (14.79)64.05 (13.87)BMI, No.2733538.002 Median (IQR)31.80 (25.83-39.48)28.63 (22.61-35.35)34.16 (29.52-41.02)Sex, No. (%)0.921 Female32 (42.67)16 (50.00)16 (50.00) Male43 (57.33)21 (48.84)22 (51.16)Race, No. (%)0.291 African American47 (62.67)22 (46.81)25 (53.19) Caucasian8 (10.67)3 (37.50)5 (62.50) Hispanic17 (22.67)9 (52.94)8 (47.06) Other3 (4.00)3 (100.00)0 (0.00)Time to intubation, No.0753738<.0001 Mean (SD)2.86 (4.47)0.15 (0.30)5.51 (5.03)Initial Fio2 at time of admission, No.21542529.109 Mean (SD)0.62 (0.32)0.69 (0.31)0.55 (0.33)Pao2/Fio2 at intubation, No.4713437.460 Median (IQR)162.00 (106.00-316.00)205.50 (106.00-378.00)160.00 (99.00-268.00)Positive end expiratory pressure, No.0753738.027 Mean (SD)10.31 (3.93)9.30 (3.75)11.29 (3.89)Plateau pressure, No.16593029.027 Mean (SD)24.42 (6.74)22.50 (4.76)26.41 (7.91)Peak pressure, No.0753738.044 Mean (SD)1630.44 (7.73)28.62 (6.75)32.21 (8.29)Driving pressure, No.16593029.154 Mean (SD)14.36 (6.12)13.23 (4.77)15.53 (7.16)Static compliance day 0, No.16593029.311 Mean (SD)37.83 (21.95)40.68 (27.23)34.88 (14.59)Static compliance day 6, No.41341420.129 Mean (SD)36.45 (16.87)31.66 (10.16)39.80 (19.87)Ventilatory ratio at intubation, No.6693237.078 Mean (SD)1.75 (0.78)1.57 (0.63)1.90 (0.86)Duration of ventilation, No.33422220.102 Mean (SD)7.98 (8.77)5.86 (8.40)10.30 (8.78)ICU length of stay, days, No.0753738.001 Median (IQR)9.25 (5.42-16.25)7.38 (3.88-10.21)12.31 (7.75-19.96)Length of stay, days, No.0753738.037 Median (IQR)13.00 (4.00-19.00)10.00 (1.00-15.00)15.50 (8.00-22.00)Living status, No. (%)0.563 Deceased37 (49.33)17 (45.95)20 (54.05) Living38 (50.67)20 (52.63)18 (47.37) Open table in a new tab As of data censoring on June 20, 2020, 49% of all mechanically ventilated patients had died. The median age for nonsurvivors was higher than those for survivors (70 vs 59; P = .0006). Average time to intubation was 3.88 days in nonsurvivors and 1.87 in survivors (P = .053). Nonsurvivors had higher initial Fio2 requirement (70% vs 50%; P = .139), lower Pao2/Fio2 ratio (median, 146 vs 261; P = .010), lower static compliance (32.14 vs 34.62; P = .962), and higher ventilatory ratios (1.85 vs 1.64; P = .276). Our study found late intubation (>1.27 days; median, day 4) was associated with longer ICU length of stay and longer duration of mechanical ventilation than early intubation (≤1.27 days; median, day 0). We found that nonsurvivors had a longer time to intubation than survivors in our cohort. Patients intubated later had higher driving pressures, lower static compliance, and higher ventilatory ratios. By day 6, static compliance improved in the late intubation group, whereas it declined in the early intubation group. This may be partially explained by disease improvement over time. Additionally, not all patients were included in the static compliance measures by day 6, because several patients had been extubated or expired. Low static compliance was seen in both groups of patients, albeit at varying times during the mechanical ventilation course. We did not find distinct ARDS phenotypes as previously suggested,5Marini J.J. Gattinoni L. Management of COVID-19 respiratory distress.JAMA. 2020; 323: 2329-2330Crossref PubMed Scopus (733) Google Scholar in line with results from other cohort studies, suggesting that most patients have low compliance.6Bos L.D. Paulus F. Vlaar A.P.J. Beenen L.F.M. Schultz M.J. Subphenotyping ARDS in COVID-19 patients: consequences for ventilator management.Ann Am Thorac Soc. 2020; 17: 1161-1163Crossref PubMed Scopus (65) Google Scholar, 7Schenck E.J. Hoffman K. Goyal P. et al.Respiratory mechanics and gas exchange in COVID-19 associated respiratory failure.Ann Am Thorac Soc. 2020; 17: 1158-1161Crossref PubMed Scopus (89) Google Scholar, 8Ziehr D.R. Alladina J. Petri C.R. et al.Respiratory pathophysiology of mechanically ventilated patients with COVID-19: a cohort study.Am J Respir Crit Care Med. 2020; 201: 1560-1564Crossref PubMed Scopus (323) Google Scholar, 9Gattinoni L. Coppola S. Cressoni M. Busana M. Rossi S. Chiumello D. COVID-19 does not lead to a "typical" acute respiratory distress syndrome.Am J Respir Crit Care Med. 2020; 201: 1299-1300Crossref PubMed Scopus (957) Google Scholar This study has numerous limitations, including its retrospective nature. Only patients who were polymerase chain reaction positive were included. The decision to intubate was based on clinician preference; thus, time to intubation varied. The late intubation group had a significantly longer need for mechanical ventilation and time in the ICU. Although respiratory mechanics seemingly improved in this group, our study does not account for other causes and co-morbidities that may have contributed to prolonged mechanical ventilation. Furthermore, causes of mortality were not fully analyzed. Larger cohort studies are needed to detect a difference in mortality between early and late intubation. In our cohort, all ventilated COVID-19 patients had low compliance and increased ventilatory ratios. Patients intubated later during their hospitalization appear to have worse compliance or VR with potentially higher mortality. Whether this is progression of disease or the presence of patient self-induced lung injury remains unclear. Further studies will need to be performed to determine whether onset of symptoms, time to hospitalization, timing of intubation, and pharmacotherapies are variables that can alter a patient's clinical course. Additional information: The e-Appendix can be found in the Supplemental Materials section of the online article. Download .pdf (.18 MB) Help with pdf files e-Online Data Immortal Time Bias in Comparing Late vs Early Intubation in Patients With Coronavirus Disease 2019CHESTVol. 159Issue 4PreviewI read with great interests on the study by Pandya et al1 in CHEST (February 2021), in which they compared the difference between late vs early intubation of patients with coronavirus disease 2019. They found that late intubation was associated with longer length of stay in ICU and duration of mechanical ventilation than the early intubation group. Although it is plausible that the late intubation group may experience prolonged periods of hypoxia that result in pathophysiologic derangements such as hypoxemia and multiorgan dysfunction, the finding may also be attributable to the immortal time bias. Full-Text PDF

Addressing the need for comprehensive analysis of the potentials and characteristics of ethylene production via Oxidative Coupling of Methane (OCM) process was the main motivation of performing the current study. In this context, technical, environmental and economic characteristics of alternative OCM process design structures including the integrated OCM and ethane dehydrogenation process for the industrial plants with the annual capacity of one million t ethylene production were analyzed and compared by predicting their performances using Aspen-Plus simulation and Aspen Economic Process Analyzer. The performance of the reactor section, carbon dioxide separation section and adsorption section in this simulation were mapped and validated using the observed performances of the OCM miniplant scale experimental facility constructed in TU Berlin. It was found that the operating cost in all cases is the main source of cost, so that even the one-year operating cost is estimated to be 3-4 times of the fixed cost. In the operating cost, the raw material cost stands for the major part of the cost to be around 750 million Euro annually. Most of the utility costs is needed for the energy-intense cryogenic distillation, which is avoided in the demethanizer section when adsorption unit is utilized. However, one percent loss of ethylene and significant increase on the fixed-cost are the main disadvantages of using adsorption technology. Yet, this process structure provides the fastest return of investments around 9 y based on the considered costs and the assumptions in this study. Using selective carbon dioxide membrane separation technology was also investigated and showed a marginal contribution specially by considering the expected 2% loss of ethylene in this case. If better membrane technologies for CO2 separation or preferably for ethylene separation becomes available, it can be beneficial in the whole economy of the process and in this case the best observed total energy consumed can be improved beyond current 40-50 GJ/t ethylene. Beside trying to reduce the total cost, the amount of the generated CO2 and the total energy consumed associated with production of one t of ethylene, potential of using bio-based materials for instance for producing the required adsorbents and also utilizing the whole OCM process for bio-based methane feedstocks were also taken into consideration. The technical challenges regarding the OCM catalyst and reactor operation should be addressed prior to any attempt for industrial scale operation of this process.

OBJECTIVE:We presented a rare case of recurrent hepatocellular carcinoma after liver transplant manifested as an isolated mediastinal mass.METHODS:A 62-year-old man was referred for evaluation of atypical chest pain and abnormal finding of a computed tomography of the chest. He had history of chronic hepatitis C liver cirrhosis and hepatocellular carcinoma underwent orthotopic liver transplant as a curative treatment three years earlier.RESULTS:The computed tomography of the chest demonstrated paratracheal mediastinal lymphadenopathy. He subsequently underwent endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA). The right paratracheal lymph node station 4R was sampled. Rapid on-site cytology evaluation demonstrated recurrent metastatic hepatocellular carcinoma.CONCLUSION:Pulmonologist should be cognizant of diagnostic utility of EBUS-TBNA in this clinical setting as more transplant patients on immunosuppressive medications with enlarged mediastinal lymphadenopathy of unknown origin will be referred for further evaluation.

The diagnosis of cryptogenic organizing pneumonia is usually delayed for several weeks due to treatment for presumed infectious pneumonia. We present a case of cryptogenic organizing pneumonia in a 39-year-old female who presented with shortness of breath and cough. She had both rapid clinical and radiological response to treatment with corticosteroids.

The oxidative coupling of methane (OCM) is a direct path for converting methane into ethene (ethylene), which is one of the most important building blocks for the chemical industry. Carbon dioxide is generated as a byproduct in the reactor and must be separated in order to produce the pure olefin. This step is commonly achieved by amine scrubbing, in which a significant amount of energy is consumed for regenerating the amine. In this contribution, a hybrid system employing gas separation membranes and absorption is modeled and simulated in order to carry out preliminary engineering design and economic evaluations to assess the feasibility of applying this process on industrial scale. It is demonstrated that the hybrid process offers economic advantage when compared to the standalone absorption process when carbon dioxide is used as diluent in the OCM reactor.

Having considered the promising potentials of the oxidative coupling of methane (OCM) technology with regard to the costs, energy, and environmental emissions in the production of ethylene, this process has been intensively studied by several academic and industrial groups worldwide for the last thirty years.In this work, a techno-economic analysis of a commercial-scale (1 million t/y) ethylene plant, operating based on the newest results of our UniCat OCM mini-plant analysis of the reactors and downstream units, has been performed. One of the main aspects of this work is to analyze several process-configurations to exploit the ethane as the side product of the OCM reaction for further ethylene production. The total project investment, based on the total equipment cost, as well as the variable and fixed operating costs, was estimated using the mass and energy balance information taken from Aspen Process Economic Analyzer (R) simulation results. With these costs, a discounted cash flow analysis was used to determine the production cost of ethylene, when the net present value of the project is zero. The feasibility was evaluated in terms of energy savings, CO2-emission reductions and utilities costs. The basis of the analysis is a world-scale conventional ethylene plant that converts 35 million Nm(3) per day of methane into one million metric tons per year of ethylene. Capital and operating costs are for an arbitrary remote location where natural gas is available at the price range between (sic)100-140 per 1000 m(3). Payout time for this process, with OCM and ethane reactors, is more than six years and is further reduced to five years after implementing alternative reactor configurations.

SESSION TITLE: Fellow Case Report Slide: Chest Infections III SESSION TYPE: Affiliate Case Report Slide PRESENTED ON: Tuesday, October 25, 2016 at 04:30 PM - 05:30 PM INTRODUCTION: Tuberculous (TB) pericarditis is an unusual etiology of pericardial effusion in the USA. Moreover, TB pericardial tamponade is a very rare presentation. The diagnosis is often delayed or missed, resulting in complications and increased mortality. We report a case of TB pericardial tamponade which initially required drainage but later resolved completely with treatment. CASE PRESENTATION: 70-year-old healthy female presented with shortness of breath of 2 days duration. She denied cough, fever, hemoptysis or weight loss. She had moved to USA from Guatemala a year ago. She had episodes of hypotension at presentation. Bedside echo revealed large size pericardial effusion so she underwent pericardiocentesis. CT chest showed pericardial effusion, bilateral pleural effusion & mediastinal lymphadenopathy. Work up showed ESR 120 mm/hr, borderline T-Spot test & positive ANA. Liver enzymes, HIV, hepatitis, TSH, ANA/ENA panel were unremarkable. Pericardial fluid was negative for bacterial, acid-fast, viral studies & malignancy. Pericardial biopsy revealed acute & chronic organizing fibrinous pericarditis. Cultures from pericardial fluid grew Mycobacterium tuberculosis (MTB). She was started on anti-TB treatment for 6 months with complete resolution in her symptoms. Follow up chest imagng revealed complete resolution of pericardial effusion, pleural effusion & lymphadenopathy. DISCUSSION: TB pericarditis, caused by MTB, is found in approximately 1-2 % of all cases of TB but tamponade is very rare presentation. Pericardial involvement usually develops by retrograde lymphatic spread of MTB or by hematogenous spread from primary TB infection. TB pericardial effusion usually presents with nonspecific symptoms, such as fever, night sweats, weight loss & shortness of breath. Pericardiocentesis is recommended in all suspected patients. The diagnosis is confirmed by demonstration of tubercle bacilli in the pericardial tissue or fluid. PCR for Mycobacterial DNA may also be useful for diagnosis. False positive ANA can be present in MTB, which has to be interpreted carefully. The treatment of TB pericardial effusion is generally the same as that for Pulmonary TB. CONCLUSIONS: MTB is a very rare cause of pericardial effusion in USA. High index of suspicion is essential in making correct diagnosis which can prevent late complications and increased mortality. Reference #1: Tuberculous pericarditis. Mayosi BM et al. Circulation. 2005 Reference #2: Tuberculous Pericarditis: A Complex Puzzle to Put Together. Lazaros G et al. 2015 Oct DISCLOSURE: The following authors have nothing to disclose: Upendra Kaphle, Daniel Salerno No Product/Research Disclosure Information

The Oxidative Coupling of Methane (OCM) is a direct path for the conversion of methane into ethene. Carbon dioxide is generated as an undesired reaction by-product and must be removed in the downstream separation section. This is commonly achieved by amine scrubbing, which is an energy-intensive process. An alternative hybrid process employing gas separation membranes and absorption is investigated in this contribution. Membrane and absorption processes are modeled and simulated. Several flowsheet configurations and gas compositions, reflecting different OCM reactor concepts, are considered. Preliminary economic analysis is carried out to assess the feasibility of applying this process industrially.

We report a case of severe acute respiratory distress syndrome (ARDS) complicated by a very large bronchopleural fistula (BPF) measuring 30 mm in length and evident on computed tomography (CT) chest scan. Such a large BPF is a very rare occurrence. Generally, a BPF of more than 6 mm in size is considered as large.(1) Small BPFs can be easily missed on CT scan chest, but a persistent air-leak through an adequately placed chest tube should raise suspicion for a BPF.

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BACKGROUND/PURPOSE:The diagnosis of patients with pulmonary infiltrates and human immunodeficiency virus (HIV) infection remains a challenge. In current clinical practice the gold standard for Pneumocystis jirovecii pneumonia (PCP) diagnosis remains the identification of the organism in bronco alveolar lavage (BAL) using microscopy (e.g., silver stain). (1->3)-β -d-glucan (BG) is a polysaccharide that is present within the cell wall of Pneumocystis and other fungi. METHODS:We analyzed serum and BAL lavage fluid from a cohort of 119 patients that did have HIV, a diagnosis of pneumonia and underwent bronchoscopy (FOB) for diagnosis of PCP. RESULTS:The discriminative power of serum BG for the diagnosis of PCP in this group of patients was very high. Using a cutoff of 300 pg/mL, the sensitivity, specificity, positive predictive value(PPV) and negative predictive value (NPV) were 91%, 92%, 89% and 93% respectively. A model for ROC with just serum BG (N = 108) had an AUC of 0.95. Serum procalcitonin (PCT) and BAL BG were not as accurate for the diagnosis of PCP. For BAL BG using a cutoff of 783 pg/mL, the sensitivity,specificity, positive predictive value (PPV) and negative predictive value (NPV) were 72%, 79%,72% and 79% respectively. The differences between the medians for serum PCT between the group with a without PCP did not reach statistical significance (p = 0.6137). CONCLUSION:The measurement of serum BG should be incorporated in the diagnostic work up of HIV positive patients with dyspnea and infiltrates on chest X X-ray. Our study confirms the diagnostic value of serum BG previously reported by others but we add a cutoff value that we believe is more accurate for patients with AIDS and suspicion of PCP.

Technical potentials and economical aspects of integrating the oxidative coupling of methane (OCM) process and methane reforming process, especially carbon dioxide methane reforming (dry reforming), were analyzed. First, the detailed fixed and operating costs of the OCM process were reviewed to diagnose the process deficiencies through a comprehensive techno-economic analysis. Next, the experimental data obtained from the mini-plant scale OCM facility constructed in Berlin Institute of Technology were exploited to guide the analysis and screen the conceptual alternatives of the integrated structure. Then, the performance of an adsorption system in the down streaming sections of the individual OCM process as well as in the integrated process was investigated.