Postoperative continuous non-invasive cardiac output monitoring on the ward: a feasibility study.

Postoperative hypotension is common (occurring in one third of patients) and is associated with worse clinical outcomes. The LiDCO CNAP (continuous non-invasive arterial pressure) device measures haemodynamics but has not been widely adopted in ward environments. Improved early detection of hypotension by CNAP might guide interventions to improve clinical outcomes. We aimed to find the proportion of patients who tolerated LiDCO CNAP for 12 h postoperatively, to unmask episodes of hypotension detected by continuous monitoring and to characterise the haemodynamic profile at the time of hypotension. In this feasibility study, patients undergoing major elective surgery were continuously postoperatively monitored using CNAP. Haemodynamic data gathered from CNAP, including nSVRI (nominal systemic vascular resistance index), nSVI (nominal stroke volume index), SVV (stroke volume variation) and blood pressure, were analysed using Microsoft Excel and GraphPad Prism 8. 104 patients (age (mean ± sd): 68 ± 14, male (56%)) had CNAP sited postoperatively. 39% tolerated the CNAP device for at least 12 h. Within the 104 patients a mean of 81.2 min of hypotension detected by CNAP was not detected by usual care. The proportion of low/normal/high nSVI was 71%, 27% and 2%, nSVRI was 43%, 17% and 40%, respectively. CNAP monitoring was not tolerated for 12 h in the majority of patients. There were many episodes of hypotension unmasked through continuous monitoring. Based on the advanced haemodynamic data provided it is possible that the underlying cause of a third of postoperative hypotensive episodes is vasodilation rather than hypovolaemia.Trial registry number: NCT04010058 (ClinicalTrials.gov) Date of registration: 08/07/2019.

Imaging of small airways disease, with emphasis on high resolution computed tomography.

Bronchioles are the airways less than 2-3 mm in diameter. Normal bronchioles cannot be reliably detected by means of high resolution computed tomography (HRCT). Nevertheless, in pathological cases, bronchiolar lesions can be identified by taking into account direct and indirect signs. On radiological grounds, bronchiolar lesions can be classified into four groups, on the basis of HRCT findings: 1) prevailing nodular opacities and "tree in bud" pattern; 2) consolidations or ground-glass opacities; 3) mosaic oligosemia with expiratory air-trapping; and 4) mixed cases. In this review, we present the main radiological and HRCT findings in four different entities, representing the more typical cases of bronchiolar pathology; bronchiolitis obliterans; bronchiolitis obliterans with organizing pneumonia; diffuse panbronchiolitis; and respiratory bronchiolitis with associated interstitial lung disease. HRCT sometimes allows a precise diagnosis of bronchiolar pathology; however, more often, it permits only a range of hypotheses to be advanced. More importantly, it allows a precise localization for biopsy procedures and an exact follow-up after institution of therapy. In normal subjects, less than 1% of the whole bronchial tree is visible on the standard chest radiograph. HRCT offers a good insight and invaluable information. New techniques, such as volumetric HRCT with sliding-thin-slab maximum- and minimum-intensity projections (MIP and minip) could represent an important additional tool in the evaluation of small airways disease.

Assessment of the severity of pulmonary emphysema by computed tomography.

Pulmonary emphysema is defined as an abnormal enlargement of alveolar spaces distal to the terminal bronchioles, with alveolar wall disruption and without obvious fibrosis. Clinico-functional evaluation and chest radiographic diagnosis are not highly accurate in detecting emphysema and in establishing the extent of the process of alveolar destruction. Several computed tomography (CT) techniques are now available for detection and quantitative assessment of emphysema. The results appear to correlate significantly better than chest radiography with functional impairment and pathological score. Many options have been proposed by different authors regarding CT technique. The choice, however, is essentially between inspiratory high resolution CT (HRCT) with a visual scoring system, and automated quantitative evaluation by means of a "density mask" (DM) program. This paper presents the state of the art on CT quantification of pulmonary emphysema and briefly discusses the technical options and parameters to be used, together with the problems to be solved.