THE EFFICACY OF INTRAPARTUM FETAL SURVEILLANCE WHEN FETAL PULSE OXIMETRY IS ADDED TO CARDIOTOCOGRAPHY

Objective: To determine if oxygen saturation measurement with pulse ox imetry (Spo(2)) in combination with cardiotocograghy (CTG), improves t he assessment of the intrapartum fetal condition. Study Design: Four e xpert obstetricians individually evaluated 119 cases that were monitor ed during labor: during the first session the CTG data were available, and in the second session CTG and Spo(2) data were evaluated. They we re instructed to indicate the need for intervention and to estimate th e umbilical artery pH. Results: In the non-acidotic group (umbilical a rtery pH greater than or equal to 7.15, n = 112) the average(+/- S.D.) number of interventions decreased from 27(+/- 17) to 16(+/- 9) when S po(2) was available. This reduction in number of interventions resulte d in an significantly increased specificity for two referees. In the a cidotic group (n = 7) the average number of interventions also decreas ed, from 6(+/- 2) to 4(+/- 2), and as a consequence the sensitivity de creased. The pH estimate based on CTG + Spo(2) was higher in both acid otic and non-acidotic fetuses than the estimated pH based on CTG alone . Conclusion: In this study all referees intervened less frequently wh en Spo(2) was used as an adjunct to CTG. This resulted in fewer unnece ssary operative interventions, but may also lead to unidentified fetal acidosis. The number of acidotic newborns (n = 7) was too small, howe ver, to draw definite conclusions. Larger studies should address the e fficacy of Spo(2) in detecting fetal compromise before clinical use ca n be advocated. (C) 1997 Elsevier Science Ireland Ltd.