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Fetal monitoring with the ST analyser: Need for a long-term follow-up of the infants
1884
Letters to the Editors
Fetal monitoring with the ST analyser: Need for a long-term follow-up of the infants To the Editors: The recent publication of Devaitis et al1 showed that when attending physicians were unaware to the ST analysis information, only using available cardiotocography (CTG) as per current practice, the clinical STAN guidelines had a sensitivity of less than 50% for metabolic acidemia at birth (BD O12 mmol/L). Similar results were reported by other perinatalogists with the combination of CTG and STAN: sensitivity of 30% for Haberstich et al2 and 46% for Kwee et al3 for the same degree of metabolic acidosis. Two questions have to be answered before introducing this technology for routine use in the labor wards, whereas its cost is twice higher than conventional CTG: Does the STANCCTG lower operative deliveries in comparison with CTG only? In the Swedish multicentric study, it is obvious that ST analysis plus CTG lowers the rate of operative deliveries for fetal distress (relative risk 0.83 [95% CI 0.69-0.99]).4 Is the neonatal outcome better with the STAN? In the CTG-ST group of the Swedish trial versus CTG alone, metabolic acidosis was effectively lowered (relative risk 0.47 [0.25-0.86]) when defining fetal asphyxia from a pH !7.05 and a BDecf O12 mmol/L, but no significant differences between the groups were found regarding Apgar scores, admissions to neonatal intensive care, or neonatal encephalopathy.4 In fetal lambs, the rising T/QRS reflects a catecholamine surge, activation of beta adrenoreceptors, myocardial glycogenolysis and metabolic acidosis, whereas the appearance of biphasic and negative waveforms are late markers for severe decompensation.5 From a complementary analysis of the Swedish trial conducted by Noren et al,6 it is also obvious that the STAN events are associated with a marked metabolic acidosis (mean pH at 7.07 and BDecf at 10.2 mmol/L for biphasic ST C T/QRS rise and mean pH at 7.04 and BDecf at 10.2 mmol/L for T/QRS rise only). The real issue is: must we wait for this degree of metabolic acidosis before intervening? In a recent paper by Victory et al7 mean arterial pH in the umbilical cord at birth was 7.24 G 0.07 and BE was at ÿ5.6 G 3.0 mmol/L. The values of pH (7.05) and of BEecf (ÿ12 mmol/L) selected by Amer-Wa¨hlin et al4 are lower than 2 SD, as defined by Victory et al,7 who claimed that with range values of umbilical cord blood gases at 0002-9378/$ - see front matter Ó 2005 Mosby, Inc. All rights reserved. doi:10.1016/j.ajog.2005.04.011
3 SD to 2 SD below the mean there was a substantial increase in the incidence of Apgar scores less than 7 at 5 minutes (!10), for NICU admissions (!4), and for assisted ventilation (!3). So, further long-term neurodevelopmental studies of the infants monitored by STANCCTG are needed before attesting that fetal brain cells are not more sensitive to metabolic acidosis than the fetal myocardium and before validating the STAN technology for standard intrapartum fetal surveillance. Georges J. J. Boog, MD* *Department of OBGYN University of Nantes Regional Perinatal Center 38, Avenue Jean Monnet 44093 Nantes cedex 1 France E-mail: [email protected]
References 1. Devaitis KL, Poole M, Schmid G, Penava D, Natale R, Gagnon R. ST segment analysis of the fetal electrocardiogram plus electronic fetal heart rate monitoring in labor and its relationship to umbilical cord arterial blood gases. Am J Obstet Gynecol 2004;191: 879-84. 2. Haberstich R, Vayssie`res C, David E, Sebahoun V, Schmitt B, Langer B, et al. Routine use of ST-segment of fetal electrocardiogram for monitoring labor. Gynecol Obstet Fertil 2003;31:820-6. 3. Kwee A, van der Hoorn-van den Beld CW, Veerman J, Dekkers AHS, Visser GHA. STAN S21 fetal heart monitor for fetal surveillance during labor: an observational study in 637 patients. J Matern Fetal Neonatal Med 2004;15:400-7. 4. Amer-Wa¨hlin I, Hellsten C, Noren H, Hagberg H, Herbst A, Kjellmer I, et al. Cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram for intrapartum fetal monitoring: a Swedish randomised controlled trial. Lancet 2001; 358:534-8. 5. Westgate JA, Bennet L, Brabyn C, Williams CE, Gunn AJ. ST waveform changes during repeated umbilical cord occlusions in near-term fetal sheep. Am J Obstet Gynecol 2001;184:743-51. 6. Noren H, Amer-Wa¨hlin I, Hagberg H, Herbst A, Kjellmer I, Marsal K, et al. Fetal electrocardiography in labor and neonatal outcome: data from the Swedish randomized controlled trial on intrapartum fetal monitoring. Am J Obstet Gynecol 2003;188:183-92. 7. Victory R, Penava D, da Silva O, Natale R, Richardson B. Umbilical cord pH and base excess values in relation to adverse outcome events for infants delivering at term. Am J Obstet Gynecol 2004;191: 2021-8.
Letters to the Editors
Fetal monitoring with the ST analyser: Need for a long-term follow-up of the infants To the Editors: The recent publication of Devaitis et al1 showed that when attending physicians were unaware to the ST analysis information, only using available cardiotocography (CTG) as per current practice, the clinical STAN guidelines had a sensitivity of less than 50% for metabolic acidemia at birth (BD O12 mmol/L). Similar results were reported by other perinatalogists with the combination of CTG and STAN: sensitivity of 30% for Haberstich et al2 and 46% for Kwee et al3 for the same degree of metabolic acidosis. Two questions have to be answered before introducing this technology for routine use in the labor wards, whereas its cost is twice higher than conventional CTG: Does the STANCCTG lower operative deliveries in comparison with CTG only? In the Swedish multicentric study, it is obvious that ST analysis plus CTG lowers the rate of operative deliveries for fetal distress (relative risk 0.83 [95% CI 0.69-0.99]).4 Is the neonatal outcome better with the STAN? In the CTG-ST group of the Swedish trial versus CTG alone, metabolic acidosis was effectively lowered (relative risk 0.47 [0.25-0.86]) when defining fetal asphyxia from a pH !7.05 and a BDecf O12 mmol/L, but no significant differences between the groups were found regarding Apgar scores, admissions to neonatal intensive care, or neonatal encephalopathy.4 In fetal lambs, the rising T/QRS reflects a catecholamine surge, activation of beta adrenoreceptors, myocardial glycogenolysis and metabolic acidosis, whereas the appearance of biphasic and negative waveforms are late markers for severe decompensation.5 From a complementary analysis of the Swedish trial conducted by Noren et al,6 it is also obvious that the STAN events are associated with a marked metabolic acidosis (mean pH at 7.07 and BDecf at 10.2 mmol/L for biphasic ST C T/QRS rise and mean pH at 7.04 and BDecf at 10.2 mmol/L for T/QRS rise only). The real issue is: must we wait for this degree of metabolic acidosis before intervening? In a recent paper by Victory et al7 mean arterial pH in the umbilical cord at birth was 7.24 G 0.07 and BE was at ÿ5.6 G 3.0 mmol/L. The values of pH (7.05) and of BEecf (ÿ12 mmol/L) selected by Amer-Wa¨hlin et al4 are lower than 2 SD, as defined by Victory et al,7 who claimed that with range values of umbilical cord blood gases at 0002-9378/$ - see front matter Ó 2005 Mosby, Inc. All rights reserved. doi:10.1016/j.ajog.2005.04.011
3 SD to 2 SD below the mean there was a substantial increase in the incidence of Apgar scores less than 7 at 5 minutes (!10), for NICU admissions (!4), and for assisted ventilation (!3). So, further long-term neurodevelopmental studies of the infants monitored by STANCCTG are needed before attesting that fetal brain cells are not more sensitive to metabolic acidosis than the fetal myocardium and before validating the STAN technology for standard intrapartum fetal surveillance. Georges J. J. Boog, MD* *Department of OBGYN University of Nantes Regional Perinatal Center 38, Avenue Jean Monnet 44093 Nantes cedex 1 France E-mail: [email protected]
References 1. Devaitis KL, Poole M, Schmid G, Penava D, Natale R, Gagnon R. ST segment analysis of the fetal electrocardiogram plus electronic fetal heart rate monitoring in labor and its relationship to umbilical cord arterial blood gases. Am J Obstet Gynecol 2004;191: 879-84. 2. Haberstich R, Vayssie`res C, David E, Sebahoun V, Schmitt B, Langer B, et al. Routine use of ST-segment of fetal electrocardiogram for monitoring labor. Gynecol Obstet Fertil 2003;31:820-6. 3. Kwee A, van der Hoorn-van den Beld CW, Veerman J, Dekkers AHS, Visser GHA. STAN S21 fetal heart monitor for fetal surveillance during labor: an observational study in 637 patients. J Matern Fetal Neonatal Med 2004;15:400-7. 4. Amer-Wa¨hlin I, Hellsten C, Noren H, Hagberg H, Herbst A, Kjellmer I, et al. Cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram for intrapartum fetal monitoring: a Swedish randomised controlled trial. Lancet 2001; 358:534-8. 5. Westgate JA, Bennet L, Brabyn C, Williams CE, Gunn AJ. ST waveform changes during repeated umbilical cord occlusions in near-term fetal sheep. Am J Obstet Gynecol 2001;184:743-51. 6. Noren H, Amer-Wa¨hlin I, Hagberg H, Herbst A, Kjellmer I, Marsal K, et al. Fetal electrocardiography in labor and neonatal outcome: data from the Swedish randomized controlled trial on intrapartum fetal monitoring. Am J Obstet Gynecol 2003;188:183-92. 7. Victory R, Penava D, da Silva O, Natale R, Richardson B. Umbilical cord pH and base excess values in relation to adverse outcome events for infants delivering at term. Am J Obstet Gynecol 2004;191: 2021-8.