Intact Proprioception and control of Labour Pain during Epidural Analgesia.
Abrahams M, Higgins P, Whyte P, et al (Rotunda Hosp., Dublin)
Acta Anaesthesiol Scand 43:46-50, 1999
Anesthesiologists are increasingly using a combination of a local anesthetic and an opioid administered into the epidural space for pain control in labor. The combination allows the anesthesiologist to reduce the local anesthetic dose thereby reducing the risks of inadvertent spinal injection, postural hypertension, and lower extremity motor impairment to the point that such women may, with care, be allowed to move and ambulate during labor. In this way, the superior systemic pain relief of the opioid during labor is coupled with superior pain relief during delivery offered by conduction anesthesia. The disadvantages of opioid administration are, principally, pruritis, a spontaneous complaint in 8% of the women reported here, and nausea, as well as an occasional episode of postpartum maternal respiratory depression that necessitates careful immediate postpartum surveillance. Neither of the latter 2 complications were noted in this study.
Currently, the anesthesia literature reflects an attempt to find an optimal dose of both agents to provide maximal analgesia with minimum side effects from either agent. In this study, the bupivacaine dose is reduced to 15 mg, small enough so that inadvertent spinal introduction is not a hazard, plus 100 mg of fentanyl.
Careful neurologic examination confirmed that vibration sense and proprioception were maintained in the lower extremities and that the Romberg test of posterior spinal column function was normal in the women treated. Pain relief reported by study participants was excellent. By now, most obstetricians have encountered this approach to labor analgesia, which rests on a firm foundation of reported experience.
Bofill JA, Vincent RD, Ross EL, et al [Wright State Univ, Dayton, Ohio; Univ of Alabama at Birmingham; Univ Mississippi Med Ctr, Jackson]
Nulliparous Active Labor, Epidural Analgesia, and Cesarean Delivery for Dystocia
Am J Obstet Gynecol 177: 1465-1470, 1997
Purpose – Some studies have suggested that epidural analgesia increases the risk of dystocia-related cesarean delivery. Other studies have found no such effect. This randomized trial sought to determine the impact of epidural analgesia on the rate of cesarean delivery for dystocia among nulliparous women in active labor.
Methods – The study included 100 nulliparous women in active labor. The results shows cesarean delivery for dystocia occurred in 8% of the epidural group and 6% of the narcotic group. All labor times, including the duration of the first and second stages, were similar between groups. The rate of operative vaginal delivery was higher in the epidural group. The pain scores were similar at randomization, but significantly higher in the narcotic group at every hour thereafter. This randomized trial including a strict labor management protocol and criteria for the diagnosis of active labor – does not find that epidural analgesia increases the risk of cesarean delivery. The study overcomes the shortcomings of previous studies of this question. It includes nulliparous women only; the findings do not apply to multiparous women or to women attempting vaginal birth after cesarean delivery.
There is one more publication on the same subject by D.H. Chestnut, D.H. University of Alabama at Birmingham and he has reviewed the evidence of both sides of the issue whether epidural analgesia during labor increases the incidence of cesarean delivery and he says that there is no convincing evidence that giving epidural analgesia will ever increase the rate of cesarean delivery; the risk is more likely to be affected by maternal fetal factors and obstetric management. Pregnant women in labor can safely undergo epidural analgesia given by skilled aneasthesiologist. Denying these patients access to epidural analgesia will cause them avoidable pain without significantly lowering cesarean delivery rate. `
One more publication on epidural analgesia and incidence of cesarean delivery for dystocia is by Fogel ST, Shyken JM et al. They conclude that the epidural analgesia is associated with but does not cause cesarean delivery for dystocia. Limiting epidural availability will not decrease cesarean delivery rate.
Gaiser RR, Cheek TG, Adams HK, et al [ Univ of Pennsylvania, Philadelphia]
Epidural Lidocaine for Cesarean Delivery of the Distressed Fetus
Int J Obstet Anesth 7: 27-31, 1998
Objective – Epidural anesthesia can be used for urgent cesarean delivery of a distressed fetus. Chloroprocaine is most commonly used in this situation; lidocaine with epinephrine and sodium bicarbonate also has a rapid onset of action. These 2 anesthetics were compared for epidural use in cesarean delivery of the distressed fetus.
Results – Both regimens produced adequate anesthesia; none of the patients required supplemental anesthetic. Time to achieve a T4 sensory level was 3.1 with chloroprocaine versus 4.4 min with lidocaine. Apgar scores and neurologic and adaptive capacity scores wee similar between groups. Maternal serum samples contained detectable lidocaine in 4 of the urgent case and all of the elective cases. Five newborns in the elective group had detectable serum lidocaine compared with none from the urgent group.
Conclusion – In women in labor with epidural catheters in place and a baseline epidural infusion to maintain a T10 sensory level, chloroprocaine has a faster onset than lidocaine. However, when chloroprocaine use is undesirable, lidocaine with sodium bicarbonate and epinephrine also provides a fast onset of labor analgesia. This study finds no evidence of significant ion trapping of lidocaine in distressed fetuses.
When used to extend preexisting epidural analgesia for emergency cesarean section, the onset of anesthesia is approximately 2 minutes faster with 2-chloroprocaine than with lidocaine with epinephrine and bicarobonate.