The Hypothermia Outcome Score (HOS) can be used to estimate the risk of death for hypothermic patients within 24 hours of presentation to the Emergency Department. A logistic regression equation based on the same parameters can give a more precise probability of death.
Patient database:
(1) hypothermic patients presenting at 13 facilities
(2) core body temperatures <= 35°C (15.6 to 35°C)
(3) 95% of patients were > 20 years of age
(4) 296 men and 132 women
Parameters:
(1) BUN in mg/dL on admission
(2) systolic blood pressure in mm Hg
(3) history of prehospital CPR
(4) need for tracheal intubation
(5) need for nasogastric tube placement
No separate measure for neurologic dysfunction is used. Patients with severe neurologic dysfunction would most likely be identified by the need for intubation and/or nasogastric tube placement.
|
Variable
|
Finding
|
Points for HOS
|
Logistic Equation
|
|
BUN on admission
|
<= 100 mg/dL
|
0
|
BUN value
|
|
|
> 100 mg/dL
|
12
|
BUN value
|
|
systolic blood pressure (SBP)
|
> 70 mm Hg
|
0
|
SBP value
|
|
|
measurable and <= 70 mm Hg
|
2
|
SBP value
|
|
|
absent (unmeasurable)
|
11
|
0
|
|
prehospital CPR?
|
yes
|
11
|
1
|
|
|
no
|
0
|
0
|
|
tracheal intubation?
|
yes
|
3
|
1
|
|
|
no
|
0
|
0
|
|
nasogastric tube placement?
|
yes
|
3
|
1
|
|
|
no
|
0
|
0
|
Prediction from Hypothermia Outcome Score
hypothermia outcome score =
= SUM(points for 5 variables)
|
Hypothermia Outcome Score
|
Probability of Death within 24 hours
|
|
> 18
|
71%
|
|
> 12 to 18
|
60%
|
|
> 6 to 12
|
42%
|
|
> 3 to 6
|
33%
|
|
> 0 to 3
|
20%
|
|
0
|
3%
|
(from Table 5, page 230)
Prediction from Logistic Regression Equation
Y variable =
= (-2.604) - (0.007 * (systolic blood pressure in mm Hg) + (1.759 * (prehospital CPR)) + (1.235 * (tracheal intubation)) + (0.502 * (nasogastric tube)) + (0.0235 * (BUN in mg/dL))
probability of death within first 24 hours of presentation to hospital =
= 1 / (1 + EXP(-Y))
