Table 2.

Different techniques for P.01 assessment

Technique	Advantage	Disadvantage
`Formal' occlusion	Precise;	Complicated;
technique	good;	requires specific
	repeatable	equipment and
		interruption of the
		natural breathing
		rhythm
`Quasi occlusion'	Simple;	Requires a pressure
technique (demand	no specific	trigger with an
valve)	equipment;	opening time in the
	no interruption	demand valve
	of the natural	> 100 ms;
	breathing rhythm	can be influenced by
		external factors
		(endotracheal tube
		obstruction)