Table 1. Basic patient data.

	N	%	MV	SD	Range
Female	17	28
Age	61	100	67.1	10.3	28–87
BMI	61	100	26.9	11.2	14–40
Long-term O2 therapy prior to intubation	11	18
Duration of external ventilation (days)	61	100	30.1	23.6	7–107
Tracheal cannula, yes	61	100
Never-smokers	13	21.3
Ex-smokers (>3 months)	16	26.2
Current smokers	32	52.4

MV, mean value; SD, standard deviation