Knize et al identified several prognostic factors that can help predict outcome in patients with frostbite. The authors are from the University of Colorado in Denver.
Factors affecting injury:
(1) likelihood of exposure (alcoholism or mental instability)
(2) underlying disease (peripheral vascular disease)
(3) extent of exposure (based on lowest temperature and duration of exposure)
(4) modifying factors (contact of bare flesh with metal or moisture; presence or absence of protective clothing; mobility vs immobile)
|
Parameter |
Finding |
Points |
|---|---|---|
|
duration of exposure |
< 30 minutes |
1 |
|
|
30 – 60 minutes |
2 |
|
|
1.01 – 4 hours |
3 |
|
|
4.01 – 12 hours |
4 |
|
|
12.01 – 24 hours |
5 |
|
|
> 24 hours |
6 |
|
temperature |
30 – 40°F |
1 |
|
|
20 – 29°F |
2 |
|
|
10 – 19°F |
3 |
|
|
0 – 9°F |
4 |
|
|
-1 to –10°F |
5 |
|
|
-11 to –20°F |
6 |
|
|
< - 20°F |
7 |
where:
• The duration ranges overlapped at 1, 4, and 12 hours. I modified the values above to prevent this.
• The options for temperature would be lowest temperature or mean temperature of the exposure.
unit of injury =
= (points for duration) * (points for depth of exposure temperature)
Outcomes following frostbite injury:
(1) no residua
(2) causalgia or contracture
(3) partial loss of a digit (tip, etc.)
(4) complete loss of a digit
(5) transmetatarsal amputation
(6) below the knee or below the elbow amputation
General rules:
(1) All victims exposed for > 1 hour at a temperature < 20°F and in contact with metal or moisture lost some tissue.
(2) The higher the units of injury the more extensive the tissue loss.
(3) Mobility was associated with less tissue loss (page 759).
|
Units of Injury |
Outcome |
|---|---|
|
< 2 |
no residua |
|
2 – 8 |
no residua, causalgia or contracture, partial loss of digit |
|
9 - 20 |
partial or complete loss of digit, rarely more extensive amputation |
|
> 20 |
amputation |
from Figure 6, page 753
Specialty: Emergency Medicine, Critical Care
ICD-10: ,
