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Accumulative Prognostic Index Depressant Intoxication

Purpose: To estimate the prognosis in a patient intoxicated with depressant drugs using the accumulative prognostic index (API).

Description

The prognosis for patients intoxicated with depressant agents (barbiturates, gluthethimide, meprobamate, etc.) can be predicted using periodic clinical measurements. The trend in changes over time is used to predict survival as the accumulative prognostic index (API).


Measurements taken every 4 hours:

(1) systolic blood pressure in mm Hg

(2) arterial pH

 

For each set of measurements, the final discriminant function is calculated.

 

final discriminant function (FDF) =

= (0.0785 * (systolic blood pressure in mm Hg)) + (12.529 * (arterial pH))

 

predicted survival =

= 1 / (1 + EXP(100.73 - (FDF)))

 

If the results are plotted, then the slope and intercept of the data can be used to derive the time discriminant function (TDF):

 

time discriminant function (TDF) =

= (0.892 * (intercept for line))  + (21.078 * (slope of line))

 

predicted survival using the TDF =

= accumulative prognostic index (API) =

= 1 / (1 + EXP(90.059 - (TDF)))

 

Limitation:

• The accumulative prognostic index was proposed over 25 years ago. With advances in treatment, the prognosis for a patient is probably better than predicted using the index.


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Specialty

Objective

ICD-10