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Portsmouth POSSUM Score

Purpose: To use the Portsmouth modification of the POSSUM score to estimate mortality in patients undergoing surgery.

Description

Whiteley et al modified the mortality probability calculation from the POSSUM score. Their data suggested that the original POSSUM score overestimated mortality, especially at lower scores. Prytherch et al later reported another but similar score. The authors are from the Portsmouth Hospitals in England.


Y from Whitely et al (1996) =

= (0.19 * (physiologic score)) + (0.15 * (operative severity score)) – 9.37

 

Z from Prytherch et al (1998) =

= (0.1692 * (physiologic score)) + (0.1550 * (operative severity score)) – 9.065

 

probability of mortality =

= 1 / (1 + EXP((-1) * (X)))

 

where:

• The article uses the form: LN ((probability) / (1 - (probability))) = X

 

Performance:

• The authors' data in Table 4, page 814 (Whiteley et al, 1996) and on page 1218 (Prytherch et al, 1998) shows that the modified mortality equation appears to perform quite well.


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Specialty

Objective

ICD-10