To the Editor
We read with interest the recent case report by Lee and Moll1 on the successful use of 2-chloroprocaine for labor analgesia in managing an obstetric patient case with a documented allergy to lidocaine. We reflected on our own clinical experience with 2 patients while reading this report and have additional insight in caring for these rare cases.
In regular practice, many institutions utilize 0.0625%–0.1% bupivacaine combined with fentanyl for labor analgesia, which is approximately 1/8th the concentration of bupivacaine that would be used to achieve a dense surgical blockade. Low concentrations are preferable to higher concentration local anesthetics given there is reduced motor blockade, shorter second stage of labor, and lower incidence of assisted vaginal delivery.2 With these considerations in mind, we have successfully used 0.3% 2-chloroprocaine for both initiation and maintenance of labor analgesia, which is 1/10th the concentration that would typically be given to provide surgical anesthesia. This dosing was effective and was a much lower concentration of 2-chloroprocaine than reported by Lee and Moll1 or other previous reports in obstetric patients, which reported a range of 1.5%–2% 2-chloroprocaine for initial dosing and 0.75%–1.5% 2-chloroprocaine for maintenance infusions.3
A recent review of pediatric literature cited concentrations of 2-chloroprocaine infusions (1%–1.5%) for postoperative analgesia.4 Another recent investigation examined epidural chloroprocaine concentrations ranging from 0.6% to 1.4% with fentanyl 0.4 μg/mL after lower limb orthopedic surgery. This study observed chloroprocaine 1.2% resulted in the lowest pain scores, though no significant differences in Bromage scores were appreciated among study groups.5 Lee and Moll1 stated that the patient’s motor function and ability to push were minimally affected, though no Bromage scores are reported and there is certainly potential for motor blockade, prolonged second stage, and assisted vaginal delivery when higher concentrations of local anesthetic are administered.
Low-dose fentanyl is commonly added to low concentration local anesthetic to improve the quality of labor epidural analgesia and minimize undesirable side effects of either medication. In the past, we have requested the pharmacy at our institution to prepare an infusion bag of 0.3% 2-chloroprocaine combined with fentanyl 2 μg/mL, but their review was unable to locate any reports documenting the compatibility or stability of these medications when combined. Thus, we have used plain 0.3% 2-chloroprocaine with separate epidural fentanyl doses administered with initial dosing and later in labor as needed. Our practice has been to administer epidural fentanyl 50 μg when initiating labor analgesia, and additional epidural fentanyl doses are considered during subsequent clinician-administered boluses for the management of inadequate labor analgesia.
In summary, based on our experience, it is reasonable to dose with low concentrations of plain 2-chloroprocaine (0.3%–0.4%) combined with separate doses of epidural fentanyl to achieve effective labor analgesia while also attempting to minimize risk of motor block, prolonged second stage, or assisted vaginal delivery.
John C. Coffman, MDDepartment of AnesthesiologyThe Ohio State University Wexner Medical CenterColumbus, Ohiojohn.email@example.com
Kristin I. Brower, PharmDDepartment of PharmacyThe Ohio State University Wexner Medical CenterColumbus, Ohio
Robert H. Small, MDDepartment of AnesthesiologyThe Ohio State University Wexner Medical CenterColumbus, Ohio
1. Lee SC, Moll VContinuous epidural analgesia using an ester-linked local anesthetic agent, 2-chloroprocaine, during labor: a case report. A A Case Rep. 2017;8:297299.
2. Sultan P, Murphy C, Halpern S, Carvalho BThe effect of low concentrations versus high concentrations of local anesthetics for labour analgesia on obstetric and anesthetic outcomes: a meta-analysis. Can J Anaesth. 2013;60:840854.
3. Abboud TK, Afrasiabi A, Sarkis F, et al.Continuous infusion epidural analgesia in parturients receiving bupivacaine, chloroprocaine, or lidocaine–maternal, fetal, and neonatal effects. Anesth Analg. 1984;63:421428.
4. Veneziano G, Tobias JDChloroprocaine for epidural anesthesia in infants and children. Paediatr Anaesth. 2017;27:581590.
5. Xu H, Li H, Zuo Y, et al.A multicenter study of the analgesic effects of epidural chloroprocaine after lower limb orthopedic surgery. J Clin Anesth. 2016;35:313320.