FETAL HEART-RATE CHANGES AFTER INTRATHECAL SUFENTANIL OR EPIDURAL BUPIVICAINE FOR LABOR ANALGESIA - INCIDENCE AND CLINICAL-SIGNIFICANCE

The objective of this study was to compare the incidence of intrapartu m fetal heart tracing CFHT) abnormalities and the obstetric outcome af ter intrathecal sufentanil (ITS) versus epidural bupivacaine (EB). Dur ing the period from April to September 1994, 129 patients who met incl usion criteria were prospectively identified during labor at a single university-affiliated hospital. Inclusion criteria included: singleton , gestational age greater than or equal to 36 wk, and cephalic present ation. In the ITS group, epidural anesthesia was not administered befo re 60 min after ITS. Sixty-five consecutive ITS patients were compared to 64 consecutive EB patients. Each FHT was reviewed independently by two obstetricians blinded to the type of analgesia. The FHT character istics evaluated included baseline rate, variability, and periodic cha nges. No differences in the incidence of clinically significant FHT ab normalities (recurrent late decelerations and/or bradycardia) were obs erved between the two groups (ITS 21.5% versus EB 23.4%). The rates of clinically significant FHT abnormalities in both groups was not diffe rent when patients with hypotension and medical complications were exc luded (16.9% vs 17.1%). In addition, equal rates of hypotension (18.5% vs 17.2%) were noted between the groups. In both groups there was a s ignificantly higher risk of cesarean section in patients whose previou sly normal FHT became abnormal postanalgesia when compared to patients without a new onset FHT abnormality (ITS 28.6% [4/14] versus 2.0% [1/ 51], P < 0.01; EB 33.3% [5/15] versus 8.2% [4/49], P < 0.05). This inc reased risk was associated with an increase in cesarean section for no nreassuring FHT in both groups (ITS 14.3% [2/14] versus 0% [0/51], P = 0.04; EB 13.3% [2/15] versus 0% [0/49], P = 0.05). These results supp ort the conclusion that the incidence of clinically significant FHT ab normalities and hypotension is equivalent in patients receiving ITS wh en compared to EB within the first hour of administration. During this period, patients should have continuous FHT monitoring since a new on set FHT abnormality unveils and alerts the physicians to a possible co mpromised fetal condition and a corresponding increased risk of cesare an section.