The evaluation of a tabular application of the NICE guidelines for universal interpretation of non-stress test (NST) and cardiotocograph (CTG)

Abstract

Objective: To assess consensus in the interpretation of cardiotocographs (CTGs) and non-stress tests (NSTs) between different grades of obstetric clinical staff by comparing assessment of traces by non-systematic eyeballing with assessment of traces using a tabular approach suggested by the National Institute of Health and Clinical Excellence (NICE) guidelines for interpretation of CTGs and NSTs, and to identify components ofNSTs and CTGs where medical personnel experience difficulty with interpretation. Design: Prospective observational study. Setting: Maternity units of the tertiary care hospitals for the teaching and training of the Witwatersrand University postgraduates, interns and midwives. Participants: Midwives, advanced midwives, interns, medical officers, registrars and specialists working in the above-mentioned maternity units. Method: Participants were recruited at the time of formal gatherings and departmental meetings in the various institutions. Each participant was given five traces that were a combination of NSTs and CTGs to interpret and assess in a non-systematic way using three categories: baby well; baby requires further surveillance; and baby needs immediate delivery. The same participants were then given the same set of traces in a different sequence for interpreting in a systematic way using the tabular approach from the NICE guidelines on electronic fetal monitoring with a scoring modification. Main outcome measure: Differences in interpretation of CTGs by different grades of staff, and degree of certainty between study participants in the different assessment systems. Results: Twenty seven specialists, 25 registrars, 21 medical officers, 10 interns and 15 midwives participated. There were varying interpretations by individuals in both the non-systematic assessment and the systematic assessment using the NICE tabular application, with best agreement in Trace 3 (77% and 84% respectively). In the non-systematic assessment, there was a statistically significant difference in the assessment of traces 1, 2 and 4 between the different grades of staff(P-values<0.01, 0.03 and <0.01 respectively). There was no statistically significant difference when the traces were assessed using the NICE guidelines tabular application (P-values; Trace1 >0.99, Trace2=0.27, Trace 3 = 0.76, Trace 4 = 0.15 and Trace5 = 0.35).Certainty of the evaluation by the participants was determined if75% or more of the participants agreed on a classification. Using the NICE guidelines, there was uncertainty (failure to agree on classification by 75% or more of the participants) with baseline variability, accelerations, decelerations and overall assessment of the CTG in most of the traces. Conclusion: There is no uniformity in the assessment of traces by midwives, interns, medical officers, registrars and specialists. Some uniformity in the interpretation of traces and reduction in inter-observer variation is attained by the use of the NICE guidelines tabular application. However, baseline variability, accelerations, and decelerations remain a problem in the interpretation of NSTs and CTGs using the NICE guidelines.