LAUSR

3 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 TO THE EDITORS: In retrospectively validating their algorithm for “category II” electronic fetal heart rate (FHR) monitoring (EFM) tracings, Clark et al compare patients with and without metabolic acidosis (MA) in cord blood from 2 hospitals using different cord acquisition strategies (universal, 111 vs selective, 9). In 120 patients with MA, the algorithm mandated intervention in only 55/120 (45.8%), but only 35/55 (60.0%) received cesareans. Adherence to the algorithm would have raised the cesarean rate, but without clear benefit. In 120 controls (non-MA category II?), clinical and algorithm-driven intervention rates were comparable (18-19%). The authors did not analyze these differences or the impact of hospital, initial tracing, labor abnormalities, timing and urgency of delivery, and long-term outcomes on the risk of MA; nevertheless, they consider their results to represent the limit of what can be done with EFM. The authors’ explanations for the 54.2% (65/120) of patients with MA in whom the algorithm failed to recommend intervention challenge fundamental precepts of fetal monitoring. In 21/65 (32.3%, 17.5% of total MA), acidosis was not suspected. This undermines the notions that EFM has low false-normal rates and that category II tracings exclude MA. Some of these tracings may have been maternal, not fetal. Neonates with unanticipated MA had more benign patterns and likely required no special attention. FHR patterns may be better predictors of outcome than MA. In 22/ 65 (33.8%, 18.3%), intervention was considered “timely” (<60 minutes), but MA not preventedea significant limitation of the algorithm given forewarning from prolonged, abnormal FHR patterns. In 12/65 (18.5%, 10.0%), tracings were “inadequate” or stopped prematurely. Indeterminable tracings increase the risk of adverse outcome and deserve attention. In 10/65 (15.4%, 8.3%), presumably unpreventable MA was preceded by a sentinel event with rapid deterioration of the FHR. Factors causing the sentinel events (eg, tachysystole, hypotension) were not assessed. Avoiding both unnecessary and emergency interventions seem important goals of any algorithm. The ultimate objective of intrapartum surveillance is the prevention of injury for which even severe MA is a poor