Patient selection: adult undergoing risk-stratified major cardiac surgery
Adverse Outcome: death, cardiac arrest or unplanned ICU re-admission
Parameters:
(1) respiratory rate in breaths per minute
(2) oxygen saturation in percent
(3) supplemental oxygen category
(4) systolic blood pressure in mm Hg
(5) heart rate in beats per minute
(6) level of consciousness
(7) temperature in °C
|
Supplemental Oxygen
|
FIO2
|
Delivery
|
|
low
|
0.25 - 0.34
|
< 5 L/min Venturi mask or nasal cannulae
|
|
medium
|
0.35 - 0.44
|
>= 5.1 L/min Venturi mask or nasal cannulae
|
|
high
|
>= 0.45
|
reservoir mask
|
|
Parameters
|
Finding
|
Points
|
|
respiratory rate
|
> 17
|
0.143 * ((rate) - 17)
|
|
|
17
|
0
|
|
|
< 17
|
0.050 * (17 - (rate))
|
|
oxygen saturation
|
|
-0.09 * (percent)
|
|
supplemental oxygen
|
room air (none)
|
0
|
|
|
low
|
1.3
|
|
|
medium
|
2.13
|
|
|
high
|
2.92
|
|
systolic blood pressure
|
> 119
|
0.005 * ((SBP) - (119))
|
|
|
119
|
0
|
|
|
< 119
|
0.031 * (119 - (SBP))
|
|
heart rate
|
> 79
|
0.015 * ((rate) - 79)
|
|
|
79
|
0
|
|
|
< 79
|
-0.007 * (79 - (rate))
|
|
level of consciousness
|
alert
|
0
|
|
|
responds to voice or confused
|
1.84
|
|
|
responds to pain or drowsy
|
1.90
|
|
|
unresponsive to pain
|
3.27
|
|
temperature
|
> 36.5
|
0.145 * ((temp) - 36.5)
|
|
|
36.5
|
0
|
|
|
< 36.5
|
0.659 * (36.5 - (temp))
|
where:
• The intercept is given as a positive number. This may be needed to offset the large negative value for oxygen saturation.
value of X =
= SUM(points for all 7 parameters) + 2.259
probability of adverse outcome =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve was 0.841 for 24 hour vital signs.
