mhi is easier to use (although our nurses hate it here in singapore, because they have to make sure they decontaminate the laerdal bags regularly). it is also an "assessment" tool for lung compliance.

vhi requires the anaesthetist's consent because we have to adjust the tidal volume and switching the simv rate down. some ventilator settings are locked with password. also american-trained intensivists don't usually like it despite explanation. they are very much into low tidal volume ventilation and if we say we want to do vhi, they invariably associate it with recruitment manoeuvre. then they will want us to look into plateau pressures and applying cpap in excess of 40 cm h2o, and they have to be present etc.... but if the patient is peep-dependent and/or has airborne precautions in closed suction circuit, may be useful.