The Validation of a Fuzzy Expert System for Umbilical Cord Acid-base Analysis

Objective assessment of the neonatal outcome of labour is important, but it is a difficult and challenging problem. It is an invaluable source of information which can be used to provide feedback to clinicians, to audit a unit’s overall performance, and can guide subsequent neonatal care. Current methods are inadequate as they fail to distinguish damage that occurred during labour from damage that occurred before or after labour. Analysis of the chemical acid-base status of blood taken from the umbilical cord of an infant immediately after delivery provides information on any damage suffered by the infant due to lack of oxygen during labour. However, this process is complex and error prone, and requires expertise which is not always available on labour wards. Previous work had resulted in the development of a crisp expert system for the interpretation of umbilical acid-base status. However, this domain is characterised by uncertainty in both the basic data and the knowledge required for its interpretation. Fuzzy logic provides a technique for representing both these forms of uncertainty in a single framework. Experimental work to establish the imprecision in acid-base parameters, in conjunction with fresh knowledge elicitation sessions, allowed the creation of an expert system to validate and interpret acid-base data using fuzzy logic. The performance of the system was evaluated in a rigorous validation study. This demonstrated excellent agreement with the experts for the numeric outputs, and agreement on a par with the experts for the linguistic outputs. One output of the fuzzy expert system is a novel single dimensional measure that accurately represents the severity of acid-base results. [email protected], [email protected], [email protected]