The two most commonly used techniques in clinical use are the loss of resistance to air and to normal saline. The term loss of resistance refers to the subjective feel of a change in resistance while the epidural needle penetrates the interspinous ligament, the ligamentum flavum, and subsequently into the epidural space. This chapter evaluates whether, during the loss of resistance technique, air or saline used during epidural anesthesia influences either the efficacy of regional blockade or the incidence of complications such as accidental dural puncture rate and postdural puncture headache (PDPH). There are few prospective, controlled, randomized double-blind trials comparing the complications of air vs. saline in identifying the epidural space. Using saline as part of a loss of resistance technique to identify the epidural space is probably the most widely accepted practice worldwide among anesthesiologists.

The prevention and management of postdural puncture headache (PDPH) in the obstetric patient continues to challenge the anesthesiologist. This chapter discusses the clinical management of PDPH in obstetric patients and suggests recommendations based on current, relevant evidence. The presence of focal neurological signs may point toward other neurological problems and prompt further investigations and assessments. The low cerebrospinal fluid (CSF) volume causes a drop in subarachnoid pressure. The incidence of PDPH in obstetric patients is relatively high due to the effects of gender and young adult age. It is also related to the size and design of the needle used and the experience of the anesthesiologist carrying out the procedure. Larger randomized controlled trials may help provide insight into the optimal use of the epidural blood patch (EBP) and other treatments. Such trials will be difficult to perform due to the low incidence of accidental dural puncture (ADP) and PDPH.