Learning curve for Doppler measurement of fetal modified myocardial performance index

Abstract

To assess the learning curve for measurement of the fetal modified myocardial performance index (MPI). Three trainees with the theoretical knowledge of but without prior experience in performing MPI measurement were selected. Each trainee and one experienced examiner measured MPI in a cohort of 90 consecutive fetuses. The average difference between the three trainees and the expert in the MPI measurements was calculated; a difference below 10% was considered to indicate an accurate measurement. Individual and averaged learning curves were delineated using cumulative sum analysis (CUSUM). The gestational age at evaluation ranged from 20 + 4 to 41 + 4 (mean, 33 + 3) weeks. The CUSUM plots demonstrated that, on average, competence in performing fetal MPI measurement was achieved by 65 cases. The average number of attempts to achieve competence were 42, 77 and 83 for the ejection time, isovolumetric contraction time and isovolumetric relaxation time, respectively. Evaluation of fetal MPI by an inexperienced trainee requires on average 65 measurements to achieve competence.