D.1  Mechanical Ventilation in an Intensive Care Unit
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Description of Variables:

id          patient ID 
age         patient's age (years)
sex.female  sex: 0 if male; 1 if female
enum        cumulative number of lines by patient
from        the state from which transition may occur
to          the state to which transition may occur
            1 if ventilation OFF
            2 if ventilation ON
            3 if discharge from ICU
            4 if death
            999 if censored
estart      the beginning of the at risk period
estop       the end of the at risk period


Reference:

Grundmann H, Barwolff S, Tami A, Behnke M, Schwab F, Geffers C, Halle E, 
Gobel U, Schiller R, Jonas D, Klare I, Weist K, Witte W, Beck-Beilecke K, 
Schumacher M, Ruden H and Gastmeier P (2005). 
How many infections are caused by patient-to-patient transmission in intensive care units?
Critical Care Medicine, 33(5): 946-951.


> ventICU <- read.table("ventICU.dat", header=T)

> length(unique(ventICU$id))
  [1] 747

> dim(ventICU)
  [1] 1141    8

> ventICU[1:9,]
    id      age sex.female enum from to estart estop
1   41 75.34153          1    1    1  3      0     4
2  395 19.17380          0    1    1  3      0    24
3  710 61.56568          0    1    2  1      0    33
4  710 61.56568          0    2    1  3     33    37
5 3138 57.88038          1    1    1  3      0     8
6 3154 39.00639          0    1    1  3      0     3
7 3178 70.27762          0    1    1  2      0     1
8 3178 70.27762          0    2    2  1      1     7
9 3178 70.27762          0    3    1  3      7    24

> table(ventICU$from, ventICU$to)   
      1   2   3   4 999
  1   0  75 585  21   5
  2 319   0  72  55   9