This chapter presents evidence supporting the use of ultrasound to take the epidural catheterization and spinal injections away from being blind techniques, therefore aiming to help reduce the incidence of the potentially serious complications resulting from Central neuraxial blockade (CNB). CNB remains the gold standard technique of providing both analgesia and anesthesia in the obstetric population, a fact which is unlikely to change in the near future. Creating an ultrasound image is done in three steps: producing a sound wave, receiving the echoes and interpreting those echoes. Most diagnostic ultrasound transducers use artificial polycrystalline ferroelectric materials such as lead zirconate titanate. There is very little published data regarding the use of ultrasound for real-time visualization of epidural puncture for neuraxial blockade. Overall, the use of ultrasound in all aspects of regional anesthesia allows continual development and improvement of current techniques.

Remifentanil's safety profile in neonates combined with rapid onset and offset means that it offers potential not only as a labor analgesic, when administered as patient-controlled analgesia (PCA), but also as an adjunct to general anesthesia, particularly in high-risk obstetric patients. An ideal intravenous opiate should have an onset and offset that can match the time course of uterine contractions, while preserving uterine contractility and a reassuring cardiotocograph (CTG). The analgesia experienced should be considered worthwhile and there should be minimal maternal and neonatal effects, allowing administration up to and during delivery. Remifentanil can offer sedation and analgesia for the anxious patient without the risk of persistent opioid effects. Systemic opioids are the mainstay of managing discomfort during epidural anesthesia for cesarean section. High doses of remifentanil with general anesthesia have unpredictable neonatal effects, making attendance by a physician trained in neonatal resuscitation mandatory.

This chapter reviews the use of regional anesthesia techniques in obese patients. The most extensive experience with regional anesthetic techniques in obese patients is with neuraxial anesthesia. Obese patients require less local anesthetic than their normal counterparts to achieve a similar sensory level. For a lumbar approach for either an epidural or spinal anesthetic, a cooperative patient can be asked to identify the "midpoint of your body". The incidence of complications with epidural anesthesia increases with increasing weight. As with epidural anesthesia, obesity is an important factor influencing spinal anesthesia. Neuraxial anesthesia is often used in combination with general anesthesia during surgery to reduce the amount of inhalational and intravenous agents. All peripheral nerve blocks were performed using a nerve stimulator technique. Overweight and obese patients should not be excluded from undergoing regional anesthesia in the ambulatory setting.