A Proposal for Standardized Management of FHR Patterns. Prior Approaches to Consensus

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1 A Proposal for Standardized Management of FHR Patterns J T Parer, MD, PhD Maternal Fetal Medicine Department of Obstetrics, Gynecology & Reprod Sci University of California San Francisco Obstetrics & Gynecology Update: What does the Evidence Tell us? San Francisco, California October 18, 2007 Prior Approaches to Consensus FIGO Workshop on FHR Guidelines. Int J Gyn & Ob, 1987 NICHD FHR Guidelines AJOG & JOGNN, 1997 RCOG Clin Effectiveness Support Unit. Use of EFM. RCOG Press, 2001 SOGC Policy Statement on Fetal Health Surveillance in Labour. JSOGC 1995 ACOG Practice Bull no 70. Intrapartum FHR Monitoring,

2 Quantitation of variable decelerations Chao,

3 Three aspects of FHRM are inadequately studied Paneth et al, 1993 Reliability of pattern interpretation: Is there adequate intra- & inter-observer agreement? Validity: Are certain patterns reliably related to adverse outcomes, eg, newborn metabolic acidemia? Utility: Can timely obstetric intervention avoid adverse outcomes in cases with evolving patterns suggestive of acidemia? CLINICAL OPINION Electronic fetal heart rate monitoring: Research guidelines for interpretation National Institute of Child Health and Human Development Research Planning Workshop The purpose of the National Institutes of Health research planning workshops is to assess the research status of clinically important areas. This article reports on a workshop whose meetings were held between May 1995 and November 1996 in Bethesda, Maryland, and Chicago, Illinois. Its specific purpose was to develop standardized and unambiguous definitions for fetal heart rate tracings. The recommendations for interpreting fetal heart rate patterns are being published here and simultaneously by the Journal of Obstetric, Gynecologic, and Neonatal Nursing. (Am J Obstet Gynecol 1997;177: ) Are there associations between FHR patterns and newborn acidemia? Parer et al, 2006 The presence of moderate FHR variability, even with decelerations, is 98% associated with absence of ph <7.15 or Apgar 5 Minimal or less FHRV with decelerations has a 23% association with ph <7.15 or Apgar 5 The liklihood of acidemia increases with depth of decelerations, especially with late decelerations, and with reduced FHRV Potentially hazardous acidemia develops over a period of 1 hr or more in a fetus whose pattern evolves from normal to decelerative with reduced FHRV 3

4 Interrelations between fetal ph, FHR variability, & depth of late decelerations Paul et al, 1975 Ruptured Uterus Observations Leung et al, 1993 What FHR Factors Contribute to Urgency of Delivery? Intact survival if the fetus is delivered in 18 min or less after the fetal bradycardia signaling the rupture If the bradycardia is preceded by decelerations, the required bradycardia to delivery time is shorter; the specific time is not yet established Risk of acidemia Probability of evolution of pattern to higher risk - type of deceleration - depth of deceleration - reduction of FHR variability 4

5 XVI. NICHD Statement on FHR Monitoring (1997) Standardized definitions of FHR characteristics. Consensus that the normal pattern predicts absence of acidemia with high degree of reliability. Consensus that absent variability in the presence of decelerations or substantial bradycardia is evidence of actual or impending potentially damaging acidemia. No consensus on virtually all other patterns (~50%) which are variants of the normal pattern, due to absence of sufficient data in the literature. XVI. NICHD Statement on FHR Monitoring (1997) Standardized definitions of FHR characteristics. Consensus that the normal pattern predicts absence of acidemia with high degree of reliability. Consensus that absent variability in the presence of decelerations or substantial bradycardia is evidence of actual or impending potentially damaging acidemia. No consensus on virtually all other patterns (~50%) which are variants of the normal pattern, due to absence of sufficient data in the literature. 5

6 XVI. NICHD Statement on FHR Monitoring (1997) Standardized definitions of FHR characteristics. Consensus that the normal pattern predicts absence of acidemia with high degree of reliability. Consensus that absent variability in the presence of decelerations or substantial bradycardia is evidence of actual or impending potentially damaging acidemia. No consensus on virtually all other patterns (~50%) which are variants of the normal pattern, due to absence of sufficient data in the literature. There are deep, late decelerations with considerable loss of beat-to-beat variability, mandating prompt intervention Implications of these observations for FHR pattern management They are mostly based on observational studies (Grade III evidence), and are preliminary findings until a prospectively gathered series in unselected patients is available Such a series will correlate FHR patterns up until the time of birth, to cord acid-base state The findings support a management approach which assumes a risk of fetal acidemia based on depth of decelerations, reduction of FHRV, and a period of evolution of a worsening FHR pattern of approximately 1 hr Threshold of Acceptable Acidemia in Umbilical Arterial Blood at Birth ph > 7.1 Base excess >-12 meq/lit Helwig et al, AJOG 6

7 General hierarchy of interventions MD/CNMs: Inform< request presence at bedside< request MD able to do C/S or OVD Insert IV Conservative interventions Inform anesthetist, pediatrician OR availability Labour in OR Ancillary testing; stimulation testing, fetal blood sampling Five Gradations of Acidemia No acidemia No central fetal acidemia (adequate oxygen) No central fetal acidemia, but FHR pattern suggests intermittent reductions in O2 which may result in fetal O2 debt Fetus potentially on verge of decompensation Evidence of actual or impending damaging fetal asphyxia 7

8 Risk of Acidemia, Evolution of Patterns To More Serious, and Recommended Action Risk of Acidemia Risk of Evolution Action Green 0 Very low None Blue 0 Low Yellow 0 Moderate Orange Red Borderline/ acceptably low Unacceptably high High Not a consideration * CT = Conservative ameliorating techniques CT & begin preparation CT & increased surveillance CT & prep for urgent delivery Deliver Conservative Techniques to Ameliorate FHR Patterns Position change Hyperoxia Correct hypotension Adequate intravascular volume Correct excessive contractions (oxytocin?) Avoid constant pushing Tocolysis Amnioinfusion to correct amniotic fluid deficit 8

9 Proposed Management of the Colour Coded Categories Conservative Techniques Op Room Obstetrician Anesthetist Newborn Resuscitator Green No Patient Location Blue Yes available informed Yellow Yes available at bedside informed informed - Orange Yes immediately available at bedside present immediately available OR Red Yes open at bedside present present OR 9

10 A Proposal for Standardized Management of FHR Patterns J T Parer, MD, PhD Maternal Fetal Medicine Department of Obstetrics, Gynecology & Reprod Sci University of California San Francisco Seventh Annual University of Illinois at Chicago Wilson Perinatal Conference Chicago, Illinois October 19,