Analysis of Airway Management for Cesarean Delivery: Use of Risk and Proportion Differences.

OBJECTIVES: Securing the parturient airway is essential during general anesthesia for cesarean delivery. The purpose of this study was to compare inferior airway views provided by the use of three commonly available laryngoscopy blades-Macintosh, Miller, or Glidescope Mac-Style-to the incidence of difficult orotracheal intubation. METHODS: Following institutional review board approval, data from 449 electronic medical records in parturients undergoing general anesthesia for cesarean delivery were extracted during a 6-year period. The association of these blades with difficult orotracheal intubation was analyzed with risk and proportion differences measures of effect size. RESULTS: The overall incidence of difficult orotracheal intubation was 4.2% (95% confidence interval 2.7 - 6.5%), with 6 failed orotracheal intubations (5 laryngeal mask airways rescues and 1 mask rescue). Clinically important increases in risk differences for difficult orotracheal intubation were observed in parturients with restricted mouth openings, modified Mallampati III and IV views, and reduced thyromental distances. When modified Cormack-Lehane views were grouped into III and IV versus I and II cohorts; proportion differences for difficult orotracheal intubation were dependent upon the type of blade used, with the Miller blade providing the lowest proportion difference. CONCLUSIONS: Miller blade laryngoscopy provided the lowest proportion difference for difficult orotracheal intubation during general anesthesia for cesarean delivery. Miller blade laryngoscopy provides effective procurement of the parturient airway.

Nitrous Oxide for Labor Analgesia: What We Know to Date.

Background: Although nitrous oxide (N2O) has been used since the 1880s for labor analgesia, its popularity has only recently increased in the United States. In 2011, only 3 centers in the country offered N2O, but as of 2020, several hundred labor units have adopted its use. Methods: We reviewed the literature and summarize the mechanism of action, clinical uses, and efficacy of N2O for labor analgesia, as well as patient satisfaction related to its use. Results: N2O has several proposed mechanisms of action that make it a viable option for all 3 stages of labor and postpartum procedures. N2O has been shown to be a safe option for both mom and baby during labor and delivery. Studies support N2O as an analgesic for laboring. Even though 40% to 60% of women who use N2O convert to a labor epidural analgesia, satisfaction surveys indicate that analgesia is not the only factor contributing to the use of N2O during labor. Conclusion: The use of N2O has increased in labor and delivery units across the United States since 2011. Despite inferior analgesic properties compared to epidural analgesia, N2O offers a safe alternative for many parturients who want a greater sense of control and mobility.

Epidural anesthesia for repeat cesarean delivery in a parturient with Klippel-Feil syndrome.

A patient with Klippel-Feil syndrome, morbid obesity, and scoliosis required cesarean delivery. Her previous cesarean deliveries were performed under general anesthesia. She desired a regional technique. Following aspiration prophylaxis and placement of standard monitors, ultrasound was used to identify midline and L(2-3) interspace. Unintentional dural puncture occurred at 10 cm, with an inability to advance the catheter. On second attempt, an epidural catheter was placed easily. After negative test dose, 18 ml of 2% lidocaine with epinephrine was administered to the patient. A T4 level was achieved. The patient tolerated surgery well. Complete block resolution occurred at 4 hours with no neurologic sequelae.