Non-invasive ventilation: interpretation of ventilator supplied data

The increasing number of patients treated by long-term non-invasive ventilation (NIV) challenges the capacity of specialised centres to perform in-hospital follow-up evaluations and requires, therefore, from the clinician a thorough and critical appraisal of the information provided by ventilator software as an important component of follow-up assessment. A systematic approach of the information is required along with a knowledge of the limitations in the reliability of some parameters and the variability in modes of reporting, which may be confusing.

This review reports the summary of observations made by a multinational group of experts in this field (SomnoNIV) over several years, and the relevant items from the medical literature.

We suggest a framework for a systematic approach of items provided by ventilator software, as well as a discussion of the different modes of reporting physiological variables according to manufacturers and pitfalls associated with some variables. An extensive iconography is included to illustrate and explicit the presentation of respiratory events occurring under NIV (impact of leaks, different patient-ventilator asynchronies, impact of inappropriate settings).

The analysis of the detailed tracings provided by the ventilator, and, importantly, the knowledge that these signals are modified and processed by the ventilator software and are not raw data, is important for the understanding of patient-ventilator interaction.