Humidification and non-invasive ventilation are frequently used together, despite the lack of precise recommendations regarding this practice. We aimed to analyse the impact of active external and built-in humidifiers on the performance of home ventilators, focusing on their pressurization efficacy and their behaviour under different inspiratory efforts. We designed a bench study of a lung simulator programmed to emulate mechanical conditions similar to those experienced by real respiratory patients and to simulate three different levels of inspiratory effort: five different commonly used home NIV devices and active humidifiers attached to the latter (internal or "built-in") or to the circuit (external). To test ventilator pressurization under different humidification and effort settings, pressure-time products in the first 300ms and 500ms of the respiratory cycle were calculated in the 45 situations simulated. Inferential statistical analysis was performed. A significant reduction of PTP 300 and PTP 500 was observed with the external humidifier in three of the devices. The same pattern was noted for another device with an internal humidifier, and only one device showed no significant changes. This impact on pressurization was commonly higher under high inspiratory effort. These results indicate the need to monitor pressure changes in the use of external humidification devices in some home NIV ventilators.

Endobronchial Ultrasound (EBUS) is essential for the evaluation of mediastinal nodes in the diagnosis and staging of cancer. Our aim was to assess the diagnostic value of EBUS in histology-representative, disease-negative cases with an initial suspicion of malignancy. We included every EBUS performed from 2008 to 2018 with the aim to evaluate mediastinal malignancy, when it resulted representative-negative (it sampled histology-valid lymphoid tissue with no microscopic disease). We considered true negative every representative-negative EBUS with either a subsequent 2 year clinical-radiological surveillance with no proved malignancy, or a subsequent malignancy-negative mediastinoscopy, and/or a subsequent malignancy-negative thoracotomy node excision. A total of 616 EBUS were accomplished, 204 resulted representative-negative, 123 of which (81% Men; Median age 68) had a suspicion of malignancy (46% lung cancer). In 92 of the 123 cases we retrieved any data. 17 cases were conducted clinical-radiological surveillance with no proved malignancy; 71 cases were conducted mediastinoscopy, 11 of which diagnosed malignancy and 4 benign processes. Other 4 cases were conducted direct thoracotomy and 1 diagnosed mediastinal malignancy. In 45 of the remaining 56 disease-negative mediastinoscopy cases we retrieved any data. 5 cases were conducted clinical-radiological surveillance with no found malignancy, and 40 cases were conducted thoracotomy, 2 of which diagnosed mediastinal malignancy. Thus, mediastinal malignancy was confirmed in 14 of 81 utterly studied negative-EBUS cases. The negative predictive value (NPV) of EBUS was 83%. In conclusion, EBUS is valid for the evaluation of mediastinal nodes, with a high NPV for malignancy.