Clinical validation of a capnodynamic method for measuring end-expiratory lung volume in critically ill patients.

RATIONALE: End-expiratory lung volume (EELV) is reduced in mechanically ventilated patients, especially in pathologic conditions. The resulting heterogeneous distribution of ventilation increases the risk for ventilation induced lung injury. Clinical measurement of EELV however, remains difficult. OBJECTIVE: Validation of a novel continuous capnodynamic method based on expired carbon dioxide (CO2) kinetics for measuring EELV in mechanically ventilated critically-ill patients. METHODS: Prospective study of mechanically ventilated patients scheduled for a diagnostic computed tomography exploration. Comparisons were made between absolute and corrected EELVCO2 values, the latter accounting for the amount of CO2 dissolved in lung tissue, with the reference EELV measured by computed tomography (EELVCT). Uncorrected and corrected EELVCO2 was compared with total CT volume (density compartments between - 1000 and 0 Hounsfield units (HU) and functional CT volume, including density compartments of - 1000 to - 200HU eliminating regions of increased shunt. We used comparative statistics including correlations and measurement of accuracy and precision by the Bland Altman method. MEASUREMENTS AND MAIN RESULTS: Of the 46 patients included in the final analysis, 25 had a diagnosis of ARDS (24 of which COVID-19). Both EELVCT and EELVCO2 were significantly reduced (39 and 40% respectively) when compared with theoretical values of functional residual capacity (p < 0.0001). Uncorrected EELVCO2 tended to overestimate EELVCT with a correlation r2 0.58; Bias - 285 and limits of agreement (LoA) (+ 513 to - 1083; 95% CI) ml. Agreement improved for the corrected EELVCO2 to a Bias of - 23 and LoA of (+ 763 to - 716; 95% CI) ml. The best agreement of the method was obtained by comparison of corrected EELVCO2 with functional EELVCT with a r2 of 0.59; Bias - 2.75 (+ 755 to - 761; 95% CI) ml. We did not observe major differences in the performance of the method between ARDS (most of them COVID related) and non-ARDS patients. CONCLUSION: In this first validation in critically ill patients, the capnodynamic method provided good estimates of both total and functional EELV. Bias improved after correcting EELVCO2 for extra-alveolar CO2 content when compared with CT estimated volume. If confirmed in further validations EELVCO2 may become an attractive monitoring option for continuously monitor EELV in critically ill mechanically ventilated patients. TRIAL REGISTRATION: clinicaltrials.gov (NCT04045262).

Water ingress into a casein film quantified using time-resolved neutron imaging.

The migration of water into a casein film was probed with neutron radiography. From the neutron transmission images, the evolution of the water saturation profiles was extracted. The results indicate that the water influx is dominated by imbibition but also contains a diffusional component. The time dependence of the water ingress was quantified using a diffusion-like equation previously also applied to imbibition. A water transport coefficient D = 0.9 × 10(-9) m(2) s(-1) was found. This value and direct observation of the images indicate that the time taken for a typical adhesive casein-based layer to become saturated with water is of the order of hours.

Neutron computed tomography of rat lungs.

Using conventional methods, three-dimensional imaging of the lung is challenging because of the low contrast between air and tissue and the large differences in dimensions between various pulmonary structures. The small distal airway structures and the high air-to-tissue ratio of lung tissue require an imaging technique which reliably discriminates between air and water. The objective of this study was to assess whether neutron computed tomography would satisfy such a requirement. This method utilizes the unique characteristic of neutrons of directly interacting with the atomic nucleus rather than being scattered by the atomic shell. Neutron computed tomography was tested in rats and allowed differentiation of larger lung structures (e.g., lobes) and distal airways. Airways could be identified reliably down to the sixth bronchial generation, in some cases even down to the tenth generation. The lung could be stabilized for sufficiently long exposure times to achieve an image resolution of 50-60 µm, which is the current physical resolution limit of the neutron computed tomography facility. Neutron computed tomography allowed excellent lung imaging without the need for additional tissue preparation or contrast media. The enhanced structural resolution obtained by applying this new research technique may improve understanding of lung physiology and respiratory therapy.

Blood-soluble Fas levels are increased in type 2 diabetic patients with peripheral vascular disease.

AIM: To investigate the possible utility of plasma sFas (soluble Fas) levels as a marker of peripheral vascular disease (PVD) in type 2 diabetic patients, and the relationship between classical cardiovascular risk factors and sFas levels in these patients. MATERIALS AND METHODS: sFas levels were measured in 57 type 2 diabetic patients with and 60 without PVD matched for age and sex. Diagnosis of PVD was established in presence of at least one of the following criteria: leg or foot amputation of vascular cause, lower-extremity arterial angioplasty or surgical by-pass, or ankle-braquial index (ABI) less than 1 in at least one side of the body. ELISA was used to measure sFas levels. RESULTS: None of the risk factors assessed total cholesterol, HDL cholesterol, triglycerides, CRP, ACE, fibrinogen, Lp(a) and homocysteine was significantly different between both groups of patients. However, patients with PVD had higher plasma sFas levels than the group without PVD (10.25+/-3.7 ng/ml VS. 8.86+/-2.6 ng/ml; p=0.02). Levels of sFas were 1.45 ng/ml (95% CI: 0.32-2.58; p=0.013) higher in PVD patients when adjusting by age, total, HDL and LDL cholesterol, triglycerides, homocysteine, CRP, ACE, arterial hypertension and tobacco smoking. Using multiple logistic regression sFas is a predictor of PVD, although not potent. CONCLUSION: Plasma sFas may be an independent marker of PVD in type 2 diabetes mellitus patients.

The design of the neutron radiography and tomography facility at the new research reactor FRM-II at Technical University Munich.

The new reactor FRM-II of Technical University Munich will offer a professional radiography and tomography facility for industrial use. The concept of the instrument and the optimization under the conditions imposed by the surrounding instruments are described for the first installment and for a second stage in an external experimental hall in about 5 years. Several detector systems for different applications will be employed and a short description of their possibilities is given.

Interventions to enhance social competence.

Social Impairment associated with attention deficit/hyperactivity disorder (ADHD) is difficult to treat. Stimulant treatment often improves social functioning, but rarely results in normalization. Behavioral approaches to improving social skills have progressed from unimodal techniques (contingency management) to packages that may combine multiple cognitive and behavioral techniques targeted directly to children and mediated by parents, teachers, other adults, and peers. Medication and behavioral treatment may improve different aspects of social impairment and may complement each other when used together. Much of the progress of treating social problems can be attributed to efforts to increase generalization across settings and durability of effects. A promising multimodal psychosocial approach is presented in detail.

[Eyberg inventory of child behavior. Standardization of the Spanish version and its usefulness in ambulatory pediatrics]. / Inventario Eyberg del comportamiento en niños. Normalización de la versión española y su utilidad para el pediatra extrahospitalario.

OBJECTIVE: Taking into account the high prevalence of behavioral problems in the pediatric outpatient clinic, a need for a useful and easy to administer tool for the evaluation of this problem arises. The psychometric characteristics of the Spanish version of the Eyberg Behavioral Child Inventory (EBCI), [in Spanish Inventario de Eyberg para el Comportamiento de Niño (IECN)], a 36-item questionnaire were established. PATIENTS AND METHODS: The ECBI inventory/questionnaire was translated into Spanish. The basis of the ECBI is the evaluation of the child's behavior through the parents' answers to the questionnaire. Healthy children between 2 and 12 years of age were included and were taken from pediatric outpatient clinics from urban and suburban areas of Barcelona and from our hospital's own ambulatory clinic. RESULTS: The final sample included 518 subjects. The mean score on the intensity scale was 96.8 and on the problem scale 3.9. Internal consistency (Cronbach's alpha) was 0.73 and the test-retest had an r of 0.89 (p < 0.001) for the intensity scale and r = 0.93 (p < 0.001) for the problem scale. Interrater reliability for the intensity scale was r = 0.58 (p < 0.001) and r = 0.32 (p < 0.001) for the problem scale. Concurrent validity between both scales was r = 0.343 (p < 0.001). CONCLUSIONS: The IECN is a useful and easy tool to apply in the pediatrician's office as a method for early detection of behavior problems.

Limulus lysate assay for early detection of certain Gram-negative corneal infections.

The limulus endotoxin assay has been previously demonstrated to be the most sensitive method available for detection of bacterial endotoxin. A commercially available form of limulus amoebocyte lysate was used in this study for detection of Gram-negative corneal infections in both experimental animals and in a group of nine patients. The limulus assay enabled rapid detection of Gram-negative infections in both the experimentally induced ulcers in rabbits and in the patients studied. False-positive reactions did not occur in corneal infections due to either Gram-positive bacteria, fungi, or herpes simplex keratitis. The limulus test proved to be more sensitive than examination of Gram-stained smears of corneal scrapings and became positive earlier than bacterial cultures. The limulus test was helpful in the diagnosis of partially antibiotic-treated corneal infections but could not be used to assess the response to antimicrobial therapy, since endotoxin persisted in the corneal scrapings for some time after initiation of therapy.