MacLeod et al reported nomograms for evaluate a patient with necrotizing fasciitis secondary to injection drug abuse. One nomogram predicts hospital survival. The authors are from the University of Dundee in Scotland and Ain Shams University in Cairo.
Patient selection: necrotizing fasciitis in a patient who injects drugs
Parameters:
(1) age in years, from 20 to 65 years
(2) blood lactate in mmol/L
(3) serum creatinine in µmol/L
(4) serum CRP in mg/L
(5) serum albumin in g/L, from 0 to 45
(6) blood glucose in mmol/L
|
Parameter
|
Points
|
|
age in years
|
78.144 - (1.202 * (age))
|
|
blood lactate
|
47 - (5.222 * (lactate))
|
|
serum CRP
|
100 - (0.1818 * (CRP))
|
|
serum albumin
|
0.6067 * (albumin)
|
|
blood glucose
|
71.831 - (2.565 * (glucose))
|
where:
• Table 7 gives glucose in mg/L but the values are more consistent with mmol/L.
|
Serum Creatinine
|
Points
|
|
20 to 60 µmmol/L
|
(1.294 * (creatinine)) + 18.93
|
|
60 to 80 µmol/L
|
(0.13 * (creatinine)) + 88.3
|
|
80 to 280 µmol/L
|
138.18 - (0.4935 * (creatinine))
|
total score =
= SUM(points for all of the parameters
Interpretation:
• minimum score: 0
• maximum score: 393.8
linear predictor =
= (0.03548 * (score)) - 10.79
probability of hospital survival =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.70.
