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Why and when to administer nebulized aminoglycosides and colistin in VAP The main reason for nebulizing aminoglycosides and colistin in VAP is to bypass the alveolar-capillary barrier which offers a severe obstacle to lung penetration following intravenous administration. In comparison to intravenous route, nebulized aminoglycosides and colistin can achieve significantly higher lung tissue concentrations necessary for the effective treatment of VAP due to MDR GNB [[1]]. In 2018, the French Society of Anaesthesia and Intensive Care Medicine (FSAICM) and the French Intensive Care Society (FICS) published guidelines regarding hospital-acquired pneumonia (HAP) in the intensive care unit [[11]], and recommended nebulized colistin and/or aminoglycosides alone in HAP due to MDR GNB susceptible to colistin and/or aminoglycosides, when no other antibiotics can be used. [Extracted from the article]

Objectives: To study whether PEEP-induced reopening of collapsed lung regions – defined as the decrease in nonaerated lung volume measured on a single or three computerized tomographic (CT) sections – is representative of the decrease in overall nonaerated lung volume. Design: Review of 39 CT scans obtained in consecutive patients with Acute Lung Injury. Settings: Fourteen-bed surgical intensive care unit of a University Hospital. Measurements and results: PEEP-induced decrease in nonaerated lung volume was measured in 39 patients with ALI on a single juxtadiaphragmatic CT section, on three CT sections – apical, hilar, and juxtadiaphragmatic – and on contiguous apex-to-diaphragm CT sections. The percentage of decrease in nonaerated lung volume following PEEP, was compared between one, three and all CT sections using a linear regression analysis and Bland and Altman's method. The decrease in nonaerated lung volume measured on a single and three CT sections was significantly correlated with the decrease in nonaerated lung volume measured on all CT sections: R=0.83, P<0.0001 for one CT section and R=0.92, P<0.0001 for three CT sections. However, measurements performed on a single CT section were poorly representative of the overall lung: bias –6%, limits of agreement ranging between –37% and +25%. Measurements performed on three CT sections overestimated by 11% the overall decrease in nonaerated lung volume: bias –11%, limits of agreement ranging between –29% and +7%. Conclusions: PEEP-induced reopening of collapsed lung regions measured on a single or three CT sections sensibly differs from the reopening of collapsed lung regions measured on the overall lung. The inhomogeneous distribution of PEEP-induced reopening of collapsed lung regions along the cephalocaudal axis probably explains these discrepancies. [ABSTRACT FROM AUTHOR]

Objective: To compare the computed tomographic (CT) analysis of the distribution of gas and tissue in the lungs of patients with ARDS with that in healthy volunteers.Design: Prospective study over a 53-month period.Setting: Fourteen-bed surgical intensive care unit of a university hospital.Patients and Participants: Seventy-one consecutive patients with early ARDS and 11 healthy volunteers.Measurements and Results: A lung CT was performed at end-expiration in patients with ARDS (at zero PEEP) and healthy volunteers. In patients with ARDS, end-expiratory lung volume (gas + tissue) and functional residual capacity (FRC) were reduced by 17% and 58% respectively, and an excess lung tissue of 701+/-321 ml was observed. The loss of gas was more pronounced in the lower than in the upper lobes. The lower lobes of 27% of the patients were characterized by "compression atelectasis," defined as a massive loss of aeration with no concomitant excess in lung tissue, and "inflammatory atelectasis," defined as a massive loss of aeration associated with an excess lung tissue, was observed in 73% of the patients. Three groups of patients were differentiated according to the appearance of their CT: 23% had diffuse attenuations evenly distributed in the two lungs, 36% had lobar attenuations predominating in the lower lobes, and 41% had patchy attenuations unevenly distributed in the two lungs. The three groups were similar regarding excess lung tissue in the upper and lower lobes and reduction in FRC in the lower lobes. In contrast, the FRC of the upper lobes was markedly lower in patients with diffuse or patchy attenuations than in healthy volunteers or patients with lobar attenuations.Conclusions: These results demonstrate that striking differences in lung morphology, corresponding to different distributions of gas within the lungs, are observed in patients whose respiratory condition fulfills the definition criteria of ARDS. [ABSTRACT FROM AUTHOR]