General principles to enhance practice patterns in gastrointestinal endoscopy.
OBJECTIVE
To develop general rules on how to pursue a therapeutic goal of interventional endoscopy without getting lost in abundant details.


METHODS
The influences of various medical interventions on the survival of a patient with gastrointestinal haemorrhage are modelled by an influence diagram. Survival is the focal point of multiple influences affecting its overall strength. Any downstream influence can represent the focal point of other preceding upstream influences. The mathematics underlying the influence diagram are similar to those of a decision tree with some notable exceptions. Its formalism allows one to consider inhibitory and additive influences and to include in the same analysis non-commensurable qualities, such as correct diagnosis, haemostasis or survival.


RESULTS
The analysis reveals five general rules. First, the large number of factors involved in successful endoscopy render the influence of each individual factor less important. Second, a single factor that exerts its influence on many subsequent factors tends to be associated with an overall greater relevance. Third, remote influences are of lesser relevance than those directly linked to the final outcome. Fourth, factors multiplied by several consecutive probabilities lose their influence. Fifth, endoscopists need to assess the relevance of individual factors with respect to the immediate goals of endoscopy, as well as the general goals of patient well-being.


CONCLUSIONS
The influence model of endoscopic haemostasis reveals several general principles that can be utilized as tools in endoscopy training.
Sonnenberg
A
A
The Department of Veterans Affairs Medical Center and The University of New Mexico, Albuquerque, NM, USA. sonnbrg@unm.edu
Gavin
M W
MW
D006471:Gastrointestinal Hemorrhage / Q000628:therapy*; D005773:Gastroscopy / Q000379:methods*; D016558:Hemostasis, Endoscopic / Q000193:education / Q000379:methods*; D006801:Humans; D008954:Models, Biological