Theoretical concept and technical details of the original ATC ventilator, as well as differences from commercially available ATC systems, were previously reported in detail [ 6, 7].
At its proximal end, the ETT was connected via a standard 15-mm bent swivel connector (Portex 100/250/001; Portex Ltd ,Hythe, Kent, UK) to the Y-piece and the tubing system of an original ATC ventilator.
At baseline, patients were switched to the Engström ventilator and ventilated according to their original settings before any measurements were performed.
Baseline data collected from the original database included demographic and ventilator data, comorbidities, admission type, patient category and cause of ARDS.
To ensure comparability of data among monitoring periods, the analysis was based on rooms in the original building with operating unit ventilators and transite panels set in aluminum framing with PCB caulk.
A ventilator equipped with the original ATC mode and operating in a pressure-targeted mode was connected to a physical lung model that consists of four equally sized glass bottles filled with copper wool.
APRV strategies on some ventilators have deviated from the original concept of a timed CPAP with a release phase, by adding pressure support (PS).
NAVA, which is based on an original physiological concept, adds new knowledge on patient-ventilator interactions during spontaneous breathing, thus helping to unravel the complex mechanisms involved in breathing control during MV.
These factors include the presence of spontaneous ventilatory efforts, irregular heart rhythm, ventilator settings different from those in the original studies [ 7, 8], cardiovascular drugs [ 8], pulmonary artery hypertension and impeding or manifest right heart failure [ 1, 2] - one or several of these factors may be present even in the majority of intensive care unit patients.
To confirm that patients in our cohort were ventilated with a low-tidal-volume protocol, we compared the ventilator settings for patients in our study with data from the original ARDS Network trial of lower-tidal-volume ventilation.
