Is the management of epidural analgesia associated with an increased risk of cesarean delivery?

OBJECTIVE: The aim of this study was to quantify the association of cesarean delivery with epidural analgesia management, specifically with the timing of epidural catheter placement in relation to labor, the type of epidural analgesia, and the use of bolus dosing. STUDY DESIGN: A retrospective cohort design was used to investigate 1561 consecutive nulliparous parturients whose labor occurred between November 1, 1996, and June 30, 1997, at Northwestern Memorial Hospital and who were delivered of term, singleton neonates in a cephalic presentation. The relationship between the management of epidural analgesia and the risk for cesarean delivery was determined with stepwise logistic regression to control for potential confounding variables. RESULTS: There was a significantly increased risk of cesarean delivery associated with decrements in cervical effacement (P =.001), cervical dilatation (P =.001), and fetal station (P =.001) at the time of epidural catheter placement. An increasing number of epidural boluses during the first stage of labor was also associated with increased risk of cesarean delivery (P =.001). After we controlled for maternal age, maternal body mass index, gestational age, infant birth weight, induction of labor, use of magnesium sulfate, and presence of chorioamnionitis, the adjusted odds of cesarean delivery associated with fetal station (odds ratio, 1.45; 95% confidence interval, 1.2-1.7) and epidural boluses (odds ratio, 1.55; 95% confidence interval, 1.3-1.8) during the first stage of labor remained significant. CONCLUSION: The management of epidural analgesia during labor was associated with the potential for increased risk of cesarean delivery. This risk increased with higher stations of the fetal head at the time of epidural catheter placement and with more frequent epidural boluses of local anesthetic during the first stage of labor.

Risk of cesarean delivery with elective induction of labor at term in nulliparous women.

OBJECTIVE: To quantify the risk of cesarean delivery associated with elective induction of labor in nulliparous women at term. METHODS: We performed a cohort study on a major urban obstetric service that serves predominantly private obstetric practices. All term, nulliparous women with vertex, singleton gestations who labored during an 8-month period (n = 1561) were divided into three groups: spontaneous labor, elective induction, and medical induction. The risk of cesarean delivery in the induction groups was determined using stepwise logistic regression to control for potential confounding factors. RESULTS: Women experiencing spontaneous labor had a 7.8% cesarean delivery rate, whereas women undergoing elective labor induction had a 17.5% cesarean delivery rate (adjusted odds ratio [OR] 1.89; 95% confidence interval [CI] 1.12, 3.18) and women undergoing medically indicated labor induction had a 17.7% cesarean delivery rate (OR 1.69; 95% CI 1.13, 2.54). Other variables that remained significant risk factors for cesarean delivery in the model included: epidural placement at less than 4 cm dilatation (OR 4.66; 95% CI 2.25, 9.66), epidural placement after 4 cm dilatation (OR 2.18; 95% CI 1.06, 4.48), chorioamnionitis (OR 4.61; 95% CI 2.89, 7.35), birth weight greater than 4000 g (OR 2.59; 95% CI 1.69, 3.97), maternal body mass index greater than 26 kg/m2 (OR 2.36; 95% CI 1.61, 3.47), Asian race (OR 2.35; 95% CI 1.04, 5.34), and magnesium sulfate use (OR 2.18; 95% CI 1.04, 4.55). CONCLUSION: Elective induction of labor is associated with a significantly increased risk of cesarean delivery in nulliparous women. Avoiding labor induction in settings of unproved benefit may aid efforts to reduce the primary cesarean delivery rate.

A study to determine the efficacy of treatments for hydrofluoric acid burns.

Hydrofluoric acid burns are characterized by progressive tissue destruction and severe pain. Fluoride ion chelators, such as salts of calcium and magnesium, have been used to treat these burns. This study was designed to compare the efficacy of several treatment methods that involve the use of these salts. Standard hydrofluoric acid burns were produced on the shaved hindquarters of rats. After being rinsed with water, the chemical burns were treated by one of seven experimental methods. The progress of the chemical burn damage was observed for 1 week by measuring the surface areas of the burns. Calcium gluconate burn jelly, 20% calcium gluconate in water, and 50% aqueous dimethyl sulfoxide did not significantly slow the spread of the burn area. However, subcutaneous injections of calcium gluconate or magnesium sulfate and topical applications of calcium gluconate in a solution of dimethyl sulfoxide significantly slowed the progress of the burns during the first 24 hours and enhanced tissue recovery for the remainder of the observation period. These results indicate that subcutaneous injections of magnesium or calcium salts appear to be more effective than conventional topical applications in the treatment of hydrofluoric acid burns. More significantly, topically applied calcium gluconate combined with a penetration enhancer, such as dimethyl sulfoxide, is as effective as injection treatments in reducing damage caused by hydrofluoric acid.