The 2017 Virginia Apgar Collection Part I: Analgesic Innovations

The first Virginia Apgar Collection was published in 2015 to highlight important research findings presented at the annual meeting of the Society of Obstetric Anesthesia and Perinatology (SOAP). This year, the Virginia Apgar Collection is presented in both the February and March issues of Anesthesia & Analgesia. The 48th annual meeting, held in Boston, Massachusetts, focused on “Care Coordination in Obstetric Anesthesia.”1 Increasingly, maternal clinicians must balance multiple, and at times competing, priorities, including maternal and perinatal safety, analgesic quality, family-centered experience of care, and efficient use of resources. Research and educational presentations at the annual SOAP meeting touched on all of these priorities. Authors for 25 highly rated presentations at the 2016 annual meeting were invited to submit manuscripts to Anesthesia & Analgesia. Eight authorship teams responded, submitted manuscripts, and satisfied multiple rounds of peer review in time for inclusion in the 2017 Virginia Apgar Collection. This issue presents Part I of the collection with a theme focused on analgesic innovations. Part II of the collection will be published in March, will focus on maternal and perinatal patient safety, and will feature the 2016 Gerard W. Ostheimer review. Innovations in analgesia are needed to close the gap between expectations and experience of labor analgesia for the delivering public.2 Although epidural analgesia is widely regarded as the gold standard for analgesic efficacy, breakthrough pain is common, particularly in the second stage of labor, and side effects range in importance, from irritating to highly distressing, including pruritus, motor blockade, hypotension, fever, and nonreassuring fetal heart rate tracings. Dural puncture epidural analgesia is a novel epidural catheter insertion technique that may enhance analgesic effectiveness when compared with standard epidural analgesia. Dural puncture epidural catheter insertion is technically identical to the combined spinal–epidural technique, except that no medications are injected through the spinal needle into the intrathecal space. The spinal needle is simply inserted and withdrawn to create a small hole in the dura; this hole is believed to facilitate bulk flow of analgesic solutions into the intrathecal space. A trial by Chau et al3 published in this issue of the Journal compared the analgesic efficacy of the dural puncture epidural technique with epidural and combined spinal–epidural catheter insertion techniques. The primary analysis compared analgesic onset, which was fastest for combined spinal–epidural analgesia and not different between the dural puncture epidural and standard epidural techniques. Regardless, secondary analyses point to favorable characteristics of the dural puncture epidural technique when compared with standard epidural analgesia, including faster sacral blockade, decreased incidence of asymmetric blockade, and fewer top-up interventions by physicians. When compared with combined spinal–epidural analgesia, the dural puncture epidural technique provided effective analgesia with fewer physician interventions, less pruritus, less hypotension, and less uterine tachysystole. A key point for clinicians is that the investigators deployed a 25-G Whitacre needle as part of the dural puncture epidural technique; previous studies have failed to demonstrate analgesic benefit when a 27-G spinal needle is used. Epidural catheter insertion may be stressful, but music played during the insertion procedure appears to worsen maternal anxiety, according to a randomized controlled trial by Drzymalski et al.4 Further research is needed to understand the potential role of music on the experience of analgesic care in labor. After epidural catheter insertion, analgesic quality depends on an effective distribution of analgesic solution in the epidural space. Programmed intermittent epidural bolus (PIEB) is an infusion pump technology in which the epidural infusion pump delivers a preprogrammed bolus dose at a set interval.5 By delivering analgesic solution under pressure, PIEB technology facilitates more extensive caudad and cephalad spread for a given analgesic dose when compared with continuous epidural infusion. Infusion pumps that combine PIEB with patient-controlled epidural analgesia are relatively new, and the optimal combination of pump settings has not been identified. A sequential allocation design by Epsztein Kanczuk et al6 published in this issue of the Journal determined that a PIEB dose of 10 mL bupivacaine 0.0625% with 2 μg/mL fentanyl administered every 40 minutes is sufficient to ensure effective analgesia in 90% of women during the first stage of labor. Alternative regimens may be equally effective. Analgesic efficacy reflects a complex interaction among the particular analgesic solution, bolus dose volume, flow rate of the PIEB, the presence and settings of coadministered patient-controlled epidural analgesia, and individual labor characteristics. Many women hope to give birth without pharmacologic analgesia but expect to use “minimum drugs to keep the pain manageable.”2 Inhaled nitrous oxide is a popular analgesic option for women who prefer to avoid epidural catheter insertion, but it is not widely available in the United States. A retrospective review of postanesthesia evaluations by Richardson et al7 compared reports of analgesic effectiveness and patient satisfaction with analgesia in women who delivered vaginally using nitrous oxide, neuraxial analgesia, or both. In their tertiary delivery center in the United States, almost 20% of women chose nitrous oxide, of whom 40% subsequently received neuraxial analgesia, and 60% delivered vaginally with nitrous oxide alone. Analgesic efficacy was highly variable for women who delivered with nitrous oxide alone, but most of these women were satisfied with their analgesic services, irrespective of whether their pain was completely relieved. For women who select neuraxial analgesia for labor pain, either initially or after a trial of nitrous oxide, the degree of pain relief correlates more directly with satisfaction with the analgesic services. An editorial by Camann8 explores the importance of identifying women’s goals and expectations when constructing an analgesic plan and the importance of analgesic efficacy for the subset of women who select neuraxial pain relief. The final article, by Patel et al,9 presents a randomized controlled trial that tested the efficacy of intraperitoneal lidocaine to facilitate postcesarean analgesia in women who received neuraxial morphine and oral adjuvants. Although the primary outcome showed no difference in pain scores beyond 2 hours, a secondary analysis suggested some analgesic benefit in the subset of women with peritoneal closure. All together, the articles that comprise Part I of the 2017 Virginia Apgar Collection point to opportunities to enhance experience of care through innovations in analgesia. Nevertheless, a large number of contextual variables determines analgesic efficacy and influences the complex relationship between analgesic strategies, resulting in pain relief and satisfaction with the experience of analgesic care. Almost certainly these topics will be revisited in future annual meetings of the SOAP. DISCLOSURES Name: Jill M. Mhyre, MD. Contribution: This author wrote the manuscript. Conflicts of Interest: Jill M. Mhyre curated and edited the 2017 Virginia Apgar Collection. This manuscript was handled by: Jean-Francois Pittet, MD.