Experimental assessment of an indirect method to measure the post-combustion flue gas flow rate in waste-to-energy plant based on multi-point measurements.

In waste-to-energy plants, the determination of the flue gas flow rate in the post-combustion section is of the utmost importance, e.g., for the verification of the compliance to the minimum residence time requirements (tres>2s) or for the control of flue gas treatment reactant injection, but the harsh conditions (high temperature and content of pollutants) do not allow for a direct measurement. The present work reports an experimental assessment of an indirect approach to estimate the flue gas flow rate in the post-combustion section of a rotary kiln plant with reduced uncertainty. This method consists on the direct measurement of the flow rate at a "colder" section of the plant (the boiler outlet) combined to the simultaneous measurements of flue gas composition measurements upstream and downstream of the boiler. From these measurements it is then possible to determine the mass of false air and to retrieve the actual flue gas flow-rate in the post-combustion chamber. A massive experimental campaign has been conducted at a full-scale medical waste incinerator, in which flue gas flow rate was estimated at different waste loads and ambient conditions. The results show that the percentage of false air can be significant and simply neglecting it can lead to substantial under-performance of the plant. Issues related to the practical implementation of the methods are illustrated in detail and the possibility to extend the methodology towards an online determination of post-combustion flue gas flow rate is discussed.

Study protocol: understanding the pathophysiologic mechanisms underlying delirium in older people undergoing hip fracture surgery.

BACKGROUND: Postoperative delirium (POD) is a common complication of older people undergoing hip fracture surgery, which negatively affects clinical- and healthcare-related outcomes. Unfortunately, POD pathophysiology is still largely unknown, despite previous studies showing that neuroinflammation, neuroendocrine dysfunction, increased reactive oxidative stress (ROS), and endothelial dysfunctions may be involved. There is also evidence that many of the pathophysiological mechanisms which are involved in delirium are involved in sarcopenia too. This article describes the protocol of a pilot study to evaluate the feasibility of a larger one that will explore the pathophysiological mechanisms correlating POD with sarcopenia. We will analyse whether various biomarkers reflecting neuroinflammation, ROS, neuroendocrine disorders, and microvasculature lesions will be simultaneously expressed in in the blood, cerebrospinal fluid (CSF), and muscles of patients developing POD. METHODS: Two centres will be involved in this study, each recruiting a convenient sample of ten older patients with hip fracture. All of them will undergo a baseline Comprehensive Geriatric Assessment, which will be used to construct a Rockwood-based Frailty Index (FI). Blood samples will be collected for each patient on the day of surgery and 1 day before. Additionally, CSF and muscle fragments will be taken and given to a biologist for subsequent analyses. The presence of POD will be assessed in each patient every morning until hospital discharge using the 4AT. Delirium subtypes and severity will be assessed using the Delirium Motor Subtype Scale-4 and the Delirium-O-Meter, respectively. We will also evaluate the patient's functional status at discharge, using the Cumulated Ambulation Score. DISCUSSION: This study will be the first to correlate biomarkers of blood, CSF, and muscle in older patients with hip fracture.

Time course of endogenous nitric oxide inhibitors in severe sepsis in humans.

AIM: Asymmetric and symmetric dimethylarginines (ADMA and SDMA, respectively) are protein breakdown markers; both compete with arginine for cellular transport and both are excreted in urine. Moreover, ADMA is a non-selective inhibitor of nitric oxide (NO) synthase that is metabolized by a specific hydrolase in which the activity during stress remains controversial. While an increase in ADMA is known to be associated with adverse events, little is known about SDMA. We investigated plasma ADMA and SDMA levels during ICU stay to reveal the time course of endogenous NO inhibition in patients with sepsis. METHODS: A post hoc analysis from a prospective random controlled trial conducted in three ICUs was performed to study the pathophysiological pathways of sepsis. ADMA, SDMA, the ratio of ADMA/SDMA (a marker of ADMA catabolism), arginine, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and C reactive protein (CRP) were measured on days 1, 3, 6, 9, 12 and at discharge in 72 consecutive severely septic patients. RESULTS: Fasting basal glycemia, creatinine, IL-6, TNF-alpha, CRP, ADMA, and SDMA were higher than normal. The ADMA/SDMA ratio was decreased by 50%, and arginine levels were low. ADMA levels were related to the total Sequential Organ Failure Assessment (SOFA) scores and arginine levels, and inversely related to IL-6 and CRP levels. SDMA levels were related to Simplified Acute Physiologic Scores II (SAPS II), SOFA scores, blood urea, creatinine, and arginine levels. The ADMA/SDMA ratio was inversely related to IL-6 levels. In 58 ICU survivors, creatinine, IL-6, and CRP levels decreased over time; ADMA levels increased, SDMA levels remained stable, and the ADMA/SDMA ratio increased. In 14 non-survivors, creatinine, IL-6, TNF-alpha, CRP, and ADMA levels were stable, whereas the SDMA levels increased and the ADMA/SDMA ratio remained low. In both ICU survivors and non-survivors, the levels on the last ICU day confirmed the data trends. SDMA, but not ADMA, was associated with ICU mortality. CONCLUSION: ADMA catabolism appears to be activated by inflammation; its increase during the advanced septic phase in surviving patients may suggest an endogenous inhibition of NO synthesis during the full-blown septic phase. In severe sepsis, SDMA, but not ADMA, appears to be a marker of alterations in vital functions and mortality.

Etiology of respiratory failure is related to mortality in critically ill patients affected by a hematological malignancy: a retrospective study.

AIM: The outcomes of patients affected by hematologic malignancies (HM) admitted to Intensive Care Units (ICUs) because of life-threatening complications are still considered to be poor. The aim of this study was to assess the incidence and impact of cardiac dysfunction on the outcome of these patients. METHODS: We retrospectively reviewed the records of the 48 patients (both adult and pediatric) with HM admitted in our ICU over the last four years, collecting data on admission diagnosis, type of HM, laboratory values and organ failure. RESULTS: All patients were admitted with respiratory failure. The overall mortality rate was 50% and the mortality rates were similar among patients with different types of HM. Septic shock and multiple organ failure were the leading causes of death. The overall incidence of cardiac dysfunction was high (31%). Interestingly, the ICU mortality of this subgroup was 27%, while the mortality of the rest of the population was 61% (p<0.05). CONCLUSIONS: ICU patients with HM have high mortality. Respiratory failure caused by cardiac dysfunction seems to be associated with a lower risk of death.

Which drugs for the control of fever in critical patients.

It has been estimated that nosocomial fever occurs in approximately one-third of hospitalized patients. The incidence is even higher in critically-ill patients in whom both infectious and noninfectious etiologies of fever are common. Polypeptide cytokines (endogenous pyrogens) such as interleukin-1b (IL-1b), tumor necrosis factor (TNF) and interleukin-6 (IL-6) act directly on the hypothalamus to effect a fever response by promoting an increase in heat generation and a decrease in heat loss. There is widespread acceptance that in most if not all critically ill neurologic patients fever should be treated but still it is not clear if fever per se in nonneurologic critically ill patients should be treated too. We review physical and pharmacological methods presently utilized to treat fever in critically ill patients.

[Angio-immunoblastic lymphadenopathy. Apropos of a clinical case]. / Linfoadenopatia angio-immunoblastica. A proposito di un caso clinico.

Reference is made to a personal case in an account of the clinical and pathological criteria that provide the diagnostic hinges of angio-immunoblastic lymphadenopathy. Stress is laid on the systemic and progressive nature of the disease, and support is given to the view that is an affection of the immuno-competent system. The fact that the course is unpredictable is seen as a reason for adopting an extremely cautions therapeutic approach based on corticosteroid hormones. Resort to the cytotoxic chemotherapeutical drugs customarily employed in other lymphoproliferative forms should be reserved for a few selected cases.