**3.2. Epidural PCA**

Epidural patient‐controlled analgesia (EPCA) is the second most significant method used and studied within the PCA approach. Its use is mainly for control of acute postoperative pain, commonly in patients undergoing orthopedic, abdominal and thoracic surgery [12]. EPCA allows the use of opioids, local anesthetics, or a combination of both. Opioids epidural administered provide greater analgesic potency when compared to equivalent doses of opioid administered intravenously [53].

Although both opioids and local anesthetics represent feasible options, local anesthetics are the most appropriate strategies for patients sensitive to the opioids adverse effects, even though it is associated with a higher incidence of hypotension, motor block and urinary retention com‐ pared with the use of opioids [53]. Similarly to the PCA intravenous technique, EPCA allows patients to administer the medication in accordance with analgesic requirements. There is large evidence indicating that the EPCA represents a safe and effective method [46, 54]. A meta‐anal‐ ysis concluded that, regardless of the drug chosen, epidural provides a better analgesia pattern when compared to intravenous PCA technique [55].

In a population‐based study of 2276 surgical patients, Kim et al. [56] discloses that ropivacaine with fentanyl was able to provide good quality analgesia for up to 48 h after the several surgical procedures, with limited side effects [56].

Unlike IV‐PCA, the use of continuous infusion, coupled with the demand dose, have shown excellent results with minimal complications. Small doses of local anesthetics of long action combined with low doses of opioids (i.e., fentanyl or sufentanil) with continuous infusion rate associated with increments *bolus* may be combined [57, 58]. The following concentrations are recommended: bupivacaine: 0.05–0.125%; levobupivacaine: 0.05–0.125%; ropivacaine: 0.1–0.2%. Additionally, the following doses are recommended: demand dose: 2–4 ml; lockout: 10–20 min; continuous basal infusion: 4–10 ml/h [11].

Despite many advantages, EPCA also has limitations, especially considering the complexity of the procedure and technical staff training. In addition, there are reports of catheter migra‐ tion which may lead to failure in the procedure in 17% of cases. It has been suggested that this technique has great effectiveness but it should be used with caution considering individual factors, in order to ensure patient safety [56].

## **3.3. Patient‐controlled regional analgesia**

There are several techniques that use catheters for the purpose of providing postoperative analgesia with little or no opioid use. In this model of patient‐controlled regional analgesia, local anesthetics (ropivacaine, bupivacaine or levobupivacaine) are normally administered through a catheter located in perineural site, intraarticular region or surgical incision site. Eventually, a combination of local anesthetics and opioids can be administered by the infu‐ sion pump [12].

Several studies have addressed the effectiveness of this method for postoperative analgesia [59]. Vintar et al. [60] noted that about 80% of patients who received bupivacaine and ropivacaine at the incision site were satisfied with the outcome of the procedure and said they would use this treatment again.

Studies emphasizing the intraarticular administration of opioids and/or local anesthetics are rare. Vintar et al. [60], in a controlled clinical trial, describes that the group which received the combination of ropivacaine/morphine/ketorolac required less use of rescue analgesics in relation to other groups.

It is estimated that, during orthopedic surgery, drug administration by intraarticular can pro‐ vide 12–15 h of analgesia [61]. In this context, the most efficient strategy would be the infusion of local anesthetics via epidural. Additionally, the brachial plexus, lumbar plexus and femoral nerve and sciatic nerve are examples of sites for drugs infusion. In a clinical trial, the PCRA ropivacaine 0.2% in the brachial plexus region was effective in shoulder orthopedic surgery regarding pain intensity, opioids' use as rescue medication, and less sleep disorders [61].

In a multicenter study involving orthopedic surgeries, the perineural ropivacaine adminis‐ tration by continuous infusion or PCRA was compared to intravenous morphine. Patients receiving morphine showed higher levels of postoperative pain and required higher con‐ sumption of analgesic as rescue medication, significantly increasing the side effects such as nausea, vomiting, dizziness and sleep disturbances [62].
