Quantitative Imaging of Regional Aerosol Deposition, Lung Ventilation and Morphology by Synchrotron Radiation CT

To understand the determinants of inhaled aerosol particle distribution and targeting in the lung, knowledge of regional deposition, lung morphology and regional ventilation, is crucial. No single imaging modality allows the acquisition of all such data together. Here we assessed the feasibility of dual-energy synchrotron radiation imaging to this end in anesthetized rabbits; both in normal lung (n = 6) and following methacholine (MCH)-induced bronchoconstriction (n = 6), a model of asthma. We used K-edge subtraction CT (KES) imaging to quantitatively map the regional deposition of iodine-containing aerosol particles. Morphological and regional ventilation images were obtained, followed by quantitative regional iodine deposition maps, after 5 and 10 minutes of aerosol administration. Iodine deposition was markedly inhomogeneous both in normal lung and after induced bronchoconstrition. Deposition was significantly reduced in the MCH group at both time points, with a strong dependency on inspiratory flow in both conditions (R-2 = 0.71; p <0.0001). We demonstrate for the first time, the feasibility of KES CT for quantitative imaging of lung deposition of aerosol particles, regional ventilation and morphology. Since these are among the main factors determining lung aerosol deposition, we expect this imaging approach to bring new contributions to the understanding of lung aerosol delivery, targeting, and ultimately biological efficacy.Peer reviewe

A mean body temperature of 37 degrees C for incubated preterm infants is associated with lower energy costs in the first 11days of life

International audienceAimThis randomised trial compared the energy costs of providing incubated preterm infants born before 32weeks of gestation with homeothermia using either air temperature control (ATC) or skin servocontrol (SSC). MethodsWe studied 38 incubated preterm infants for the first 11days of life, calculating the frequency of hypothermia (37.5 degrees C) and thermal challenge, together with energy costs, based on a change in incubator air temperature of 2 degrees C above or below thermoneutrality. ResultsThe daily mean incubator air temperature was higher in ATC than SSC (p<0.05) for the first 6days, and the mean body temperature was higher in ATC (37.00.03 degrees C) than SSC (36.8 +/- 0.02; p<0.01) over the whole study period. The frequency of moderate hyperthermia was higher in ATC (p<0.001), whereas warm and cold thermal challenges were higher in SSC (p<0.001). The two groups did not differ in terms of energy costs. The time to recover birthweight was shorter in ATC (p<0.05). ConclusionIn incubators using ATC, a body temperature of 37 degrees C was associated with lower energy costs and greater weight gain at 11days of life for preterm infants. Future studies should test SSC shielded abdominal skin temperature set to 37 degrees C

Imaging Intra-Breath Cyclic Changes In Regional Pulmonary Blood Volume: Effect Of Peep, Tidal Volume And Gravity Gravity

International Conference of the American-Thoracic-Society (ATS), Washington, DC, MAY 19-24, 2017International audienc

Diffusion-Convection Interaction As A Cause Of Uneven Gas Distribution In Rabbit Lung

International Conference of the American-Thoracic-Society (ATS), Denver, CO, MAY 15-20, 2015International audienc

A mean body temperature of 37 degrees C for incubated preterm infants is associated with lower energy costs in the first 11days of life

International audienceAimThis randomised trial compared the energy costs of providing incubated preterm infants born before 32weeks of gestation with homeothermia using either air temperature control (ATC) or skin servocontrol (SSC). MethodsWe studied 38 incubated preterm infants for the first 11days of life, calculating the frequency of hypothermia (37.5 degrees C) and thermal challenge, together with energy costs, based on a change in incubator air temperature of 2 degrees C above or below thermoneutrality. ResultsThe daily mean incubator air temperature was higher in ATC than SSC (p<0.05) for the first 6days, and the mean body temperature was higher in ATC (37.00.03 degrees C) than SSC (36.8 +/- 0.02; p<0.01) over the whole study period. The frequency of moderate hyperthermia was higher in ATC (p<0.001), whereas warm and cold thermal challenges were higher in SSC (p<0.001). The two groups did not differ in terms of energy costs. The time to recover birthweight was shorter in ATC (p<0.05). ConclusionIn incubators using ATC, a body temperature of 37 degrees C was associated with lower energy costs and greater weight gain at 11days of life for preterm infants. Future studies should test SSC shielded abdominal skin temperature set to 37 degrees C