Algorithm for management of category II fetal heart rate tracings: a standardization of right sort?




This well-intended expert consensus-based algorithm has been presented as one of the options of management to prevent most cases of birth asphyxia but needs an in-depth analysis. Clark et al hypothesize that the different types of decelerations have unique etiologies. However, the majority of variable (rapid) decelerations during contractions cannot be explained by the cord compression hypothesis and several US authorities have attributed these to head compression instead, and they should really be called “early decelerations.” A more scientific approach may be to correct the distorted (and fundamentally flawed?) categorization of fetal heart rate (FHR) decelerations first, which is the main underlying reason for the large confusing category II FHR patterns. Instead, subjecting more than 80% of all laboring women (category II) to a fairly complicated, cumbersome, unproven, and untested algorithm may not be fruitful. An important part of this algorithm depends on identifying significant decelerations (late and those with sixties criteria; ie, 2 or more of the following criteria present: depth 60 bpm or more, lowest value 60 or less, duration 60 seconds or longer). However, based on the Eunice Kennedy Shriver National Institute of Child Health and Human Development definitions, early and late decelerations cannot be less than 60-65 seconds in duration (descent time >30 seconds) by the accident of definition. Thus, FHR decelerations late in timing (possible hypoxemia) but <60 seconds’ duration could be classed as “variable” and hence may not necessarily be picked up as significant. Secondly, expeditious delivery has been recommended in the presence of significant decelerations (for 30 or 60 minutes) if the progress of labor is not normal. But if progress is normal, then it is not clear why and how long observation will be justified, especially when late decelerations and those with sixties criteria have a significant association with neonatal acidemia and encephalopathy. Most importantly, although the sixties criteria may have a good specificity, their sensitivity to pick up hypoxemia/acidemia seems unknown. An indirect measure like FHR pattern has considerable limitations in assessing fetal condition. Hence, to reduce birth asphyxia to a bare minimum, it seems necessary to settle for a high sensitivity at the expense of specificity. Therefore, a supplementary test is then often necessary in the presence of an abnormal FHR pattern. Fetal scalp blood sampling in the British practice is one example. The expert group would make a better case by providing some evidence and estimate of sensitivity and specificity of their algorithm in addition to the consensus opinion or belief. Standardization of terminology and management is highly desirable but it should be of the right sort to achieve the desired goal.

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May 11, 2017 | Posted by in GYNECOLOGY | Comments Off on Algorithm for management of category II fetal heart rate tracings: a standardization of right sort?

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