Use of Regional Anesthesia Techniques: Analysis of Institutional Enhanced Recovery After Surgery Protocols for Colorectal Surgery

Introduction

Enhanced Recovery After Surgery (ERAS^®) protocols are evidence-based approaches that aim to reduce morbidity and speed recovery from surgery. ¹ There are many fundamental facets to these protocols with basic principles being patient education, carbohydrate loading, perioperative fluid management and multimodal analgesia.^2,3 In patients undergoing colorectal surgery, multimodal pain management with emphasis on minimizing the use of opioids to reduce the risk of postoperative ileus and sedation is critical to ERAS. The two key components of the multimodal analgesic approach are pharmacological agents and regional anesthesia. Regional techniques that can be found within ERAS protocols for colorectal surgery include TAP blocks, rectus sheath blocks, continuous wound infiltration (CWI), as well as spinal and thoracic epidural anesthesia (TEA). Both neuraxial anesthesia and peripheral nerve blocks have been studied extensively in colorectal surgery. TEA has been the pain regional anesthetic modality in open surgery, proving to be more effective than intravenous opioids in speeding up recovery and reducing opioid side effects.^4–6 However, it may also result in procedure-related complications, hypotension from sympathectomy, limited patient mobility postoperatively, and failure to relieve pain. Spinal analgesia with intrathecal opioid may prevent some of the complications associated with TEA, but higher intrathecal opioid doses may contribute to postoperative respiratory depression.^7,8 Peripheral nerve blocks such as TAP, quadratus lumborum, and rectus sheath blocks are gaining popularity given a good safety profile and encouraging outcomes in both open and laparoscopic surgery.^9–11 Wound catheters providing continuous infiltration with a local anesthetic have shown promise in some procedures, and may provide similar benefit to epidural anesthesia.^12,13

This study aims to compare and contrast the use of regional anesthesia based on the analysis of 15 institutional ERAS protocols for both open and laparoscopic colorectal surgery. It is our hypothesis that there will be a fundamental consensus among the protocols reviewed, with some notable differences in the choice of preferred regional anesthetic technique.

Materials and Methods

ERAS protocols for open and laparoscopic colorectal surgery were obtained from 15 different healthcare facilities. Protocols were gathered using several different methods, with five of the protocols downloaded from the website of American Society for Enhanced Recovery (ASER). The remaining protocols were obtained through direct contact or Google search. ERAS protocols for colorectal surgery were acquired from the following institutions; Banner Health, Brigham and Women's Hospital, Cooper University, Chicago University, Dartmouth, Duke, Johns Hopkins, Mayo Clinic Phoenix, Mayo Clinic Rochester, McGill University, Stanford, University California San Francisco, University of Alabama, University of Virginia, and North Shore Hospital in Auckland, New Zealand. A comparison was then done in regard to the regional component of multimodal analgesia noting the similarities and differences. This study did not require an institutional review board approval since no human subject data were involved.

Results

The most commonly used regional technique among protocols was epidural anesthesia, with TAP blocks being the next most common. Rectus sheath blocks and continuous wound catheters were only mentioned in one protocol each. TEA was found in 10 out of 15 pathways. Suggested levels of insertion included mid-thoracic, T7–T9, T8–T10, T8–T9 for right colectomy, T9–T10 for left colectomy or sigmoidectomy, T10–T11 or T7–T10 for colonic, and T10–T12 for rectal surgery. The indications for the use of epidurals varied throughout the protocols (Table 1). These ranged from being standard for all open and laparoscopic procedures to no routine placement at all. Some protocols did not specifically advocate for TEA, referring decision making to a multidisciplinary case-by-case process. Bupivacaine was the most commonly used local anesthetic; however, there was variation in concentration and infusion rates. In addition to bupivacaine, lidocaine and ropivacaine were also used. The addition of hydromorphone to epidural infusion was seen in one protocol and fentanyl in two. Spinal anesthesia was part of five protocols, with four specifically recommending opioid-only techniques. One protocol stated a preference for opioid-only spinal over epidural anesthesia.

TAP blocks were incorporated into 8 of the 15 protocols. Indications for use of TAP blocks also varied widely, but were most commonly utilized for analgesia in laparoscopic cases. One pathway suggested their use as a rescue technique in the postanesthesia care unit. Rectus sheath blocks were not standard in any of the reviewed protocols and were suggested to use “if appropriate” in one pathway. Continuous wound catheters were found in one protocol and were indicated for major liver resections or deep inferior epigastric perforator (DIEP) flaps.

Discussion

Epidural anesthesia was the most commonly used neuraxial analgesia modality in the protocols reviewed. Suggested insertion sites ranged from T7 to T12, depending on the operative site. Two recent meta-analyses demonstrated that TEA is superior to patient-controlled analgesia (PCA) for analgesia in following abdominal surgical procedures, and specifically for colorectal surgery.^5,6 Specific advantages of TEA use in colorectal surgery are reduced incidence of paralytic ileus, attenuation of the surgical stress response, improved intestinal blood flow, improved analgesia, and reduction of opioid use. This leads to earlier oral intake, ambulation, and return of bowel function, all of which are concordant with the principles of ERAS. ⁴

In cases of block failure or when TEA is contraindicated, an intraoperative lidocaine infusion can be substituted. Postoperatively, if TEA is contraindicated, there is moderate supporting evidence for the use of PCA and/or oral sustained-release opioids to increase duration of analgesia and sleep. ¹⁴ Thoracic epidurals are frequently complicated by vasodilatory hypotension and urinary retention, and infrequently by neural structure injuries; however, on balance, their use is generally regarded as safe. ⁵

Spinal anesthesia was recommended in five protocols and four of these were intrathecal opioid-only techniques. The use of intrathecal opioids for spinal anesthesia has been shown to decrease postoperative opioid consumption, and decrease pain at rest and with movement. ⁸ These benefits are most notable in patients undergoing abdominal surgery. ⁸ Current recommendations advocate for doses of intrathecal morphine <0.3 mg as higher doses are associated with sedation, respiratory depression, and arterial hypoxemia. ⁷ There is some evidence that spinal anesthesia compared to TEA results in earlier mobilization and hospital discharge and thus may be more suitable for enhanced recovery after open and laparoscopic surgery. ¹⁵

TAP blocks were found in 8 of the 15 protocols and most commonly indicated for laparoscopic procedures. TAP blocks have been used in laparoscopic surgery and can be combined with intravenous acetaminophen to reduce opioid administration. ¹⁶ The TAP is a potential space in the anterior abdominal wall between the internal oblique and transversus abdominis muscles serving as boundaries for the nerves providing somatic innervation to the anterior and lateral abdominal walls. ¹⁷

There are numerous factors influencing analgesic outcomes in TAP blocks. These include the method of nerve localization and needle placement, population type, type of surgical procedure, operator skill, type, dose, and volume of local anesthetic used, timing of injection, and quality of clinical assessments. ¹⁸ Although shown to be effective analgesic techniques, TAP blocks are short acting and there are no substantial randomized controlled trials comparing TAP versus spinal or epidural analgesia. ¹⁹

Rectus sheath blocks were included in one protocol. Little is known about the efficacy of rectus sheath blocks in comparison with epidural anesthesia. One study showed rectus sheath blocks provided equivalent analgesia to epidural anesthesia, while avoiding some of the known potential complications involved with epidural analgesia. ¹⁰ Mean time to mobilization was also shorter in the rectus sheath cohort, but there was no difference in postoperative pain scores or duration of hospital stay. ¹⁰

Recommended indications for CWI were liver resections or DIEP flaps. Catheters placed in the preperitoneal space after laparotomy have shown to be effective in reducing postoperative pain, hastening recovery, and improving postoperative pulmonary function.^20,21 There is also evidence that CWI is noninferior to epidural analgesic; however, more clinical trials are needed. ¹²

There is a larger body of evidence for the use of neuraxial anesthesia opposed to other types of regional techniques in colorectal surgery patients, although there is emerging evidence to supporting the noninferiority of peripheral nerve blocks such as TAP and quadratus lumborum blocks. ⁹ Many of our studied protocols reflect this evidence, with all, but two, of the reviewed protocols recommending either spinal or epidural anesthesia. When considering the modality and appropriateness of neuraxial anesthesia, one must take into consideration both surgical and patient factors, as both these variables have demonstrable influence on outcome. ERAS protocols use a combination of regional and pharmacologic analgesics to accelerate recovery and reduce morbidity. It is likely that the differences observed among different institutional protocols are due to both system-level and provider-specific factors. Some institutions may be limited in the number of anesthesia staff able to perform certain blocks as well as the resources needed to manage them postoperatively. One of the limitations of this study is that only a small number of existing ERAS colorectal protocols were examined and most were limited to institutions in North America. However, our study confirms that regional anesthesia is part of all examined ERAS protocols, although some variability in approaches exists. More research is needed in the form of prospective, randomized controlled trials to show the superiority of one regional anesthetic technique over another that is specific for the surgery type.