This is a non-commercial study to explore the use of Heliox21 in a new patient cohort. The
fundamental aim is to assess the therapeutic benefits of Heliox21 and practicalities of gas
delivery in patients who require non-invasive ventilatory support following extubation on the
Intensive Care Unit. Thus, the investigators aim to extend our knowledge of the potential
role for Heliox21 in the post-extubation environment of the Intensive Care Unit. The purpose
of this study is to answer a specific, clinically relevant question. That is whether Heliox21
helps to reduce the effort of breathing in the period following withdrawal of mechanically
assisted ventilation in patients on the intensive care unit.