Calculate perioperative mortality fpr general surgical patients with P-POSSUM.
Implements the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) algorithm described by Prytherch et al. (http://dx.doi.org/10.1046/j.1365-2168.1998.00840.x).
Intended for use by qualified medical professionals only.