Regional Anesthesia in Resource-Constrained Environments

Introduction

Regional anesthesia is a relatively low-cost and widely used technique in perioperative analgesia and anesthesia. To date, it has been primarily utilized in high-income countries (HICs) where regional anesthesia has been associated with reduced postoperative pain, reduced opioid requirements, as well as increased patient satisfaction, surgical pathway efficiency, and avoidance of general anesthesia. While each of these outcomes is also relevant in low- and middle-income countries (LMICs), the role and benefits for regional anesthesia in LMICs are yet to be fully defined.

Due to significant limitations in access to analgesia and general anesthesia modalities, coupled with a disproportionately high burden of surgical diseases including trauma, the benefits of regional anesthesia may be amplified in LMICs.

Pain and surgical diseases account for more than 30% of global disease burden, which is more than that of human immunodeficiency virus (HIV), tuberculosis (TB), and malaria combined. The majority of this burden exists in LMICs where critical shortages in workforce, infrastructure, and political capacity create major barriers to pain and anesthesia care.

Pain alone is among the top ten causes of disability-adjusted life years (DALYs) worldwide. Access to pain management is widely considered a basic human right, yet reliable access to analgesia does not exist for the vast majority of the world. At present, Australia, Canada, New Zealand, the United States of America, and several European countries account for more the 90% of the world's opiate consumption, while most LMICs lack reliable access to cheap and effective medications like morphine.

For practice settings where access to opiates is limited, exploring alternative analgesia modalities such as regional anesthesia is critical, while simultaneously working to increase access to all essential analgesic options.

The barriers to regional anesthesia in resource-constrained settings are complex. In this chapter, we discuss these challenges, potential solutions, and the need for ongoing evaluation of how to best increase access to anesthesia and analgesia services worldwide.

Technique Selection and Preferred Blocks

The choice of regional anesthetic technique (e.g., ultrasound, paresthesia, or nerve stimulator) and block type (e.g., forearm or interscalene block) will be influenced by numerous factors specific to the local context. These include local disease epidemiology, provider skill level, local supply chains, as well as availability of medications and safety supplies (as discussed later in this chapter).

Safety profiles for different types of regional anesthesia vary significantly with technique, injection site, local anesthetic drug, dose, and patient weight. Each of these factors can significantly influence the risk of local anesthetic systemic toxicity (LAST). The use of ultrasound for regional anesthesia has been associated with increased safety and efficacy; however, nerve stimulator and landmark-based techniques still have a significant role.

There are no guidelines or robust data to aid decision making when weighing the risks and benefits of a proposed procedure in a resource-constrained setting. Nonetheless, there are several blocks with relatively greater potential utility and more favorable safety profiles as discussed below. Many surgical procedures commonly performed with general anesthesia in HICs can be done with regional anesthesia alone, with significant potential savings in cost and time. In addition to neuraxial anesthesia, examples include field blocks for hernias, digital blocks, axillary blocks for upper extremity procedures, topical blocks for ophthalmologic procedures, penile blocks for circumcision, intravenous regional anesthesia, forearm blocks for hand surgery, ankle blocks for foot and ankle procedures, and superficial thoracic paravertebral, pectoral, and serratus anterior blocks for breast surgery or rib fractures.

While most of these blocks can be done relatively easily without ultrasound and with acceptable safety profiles, serious complications can still occur in inexperienced hands. For example, anecdotal reports of LAST fatalities during penile blocks for circumcision are still encountered regularly in some low-income countries (LICs) and are attributed to preventable causes (incorrect dosing or technique).

In general, distal blocks and the use of ultrasound are preferred when feasible in low-resource settings for a number of reasons. Distal blocks (e.g., a forearm or ankle block instead of an axillary or femoral/popliteal block for hand or foot surgery, respectively) minimize the amount of local anesthetic dose needed, thereby reducing the risk of LAST. Furthermore, due to the lower dose of local anesthetic required and the proximity to the surgical field, distal blocks also allow for intraoperative supplementation. This can help overcome limitations of using short-acting local anesthetics for longer cases and mitigate the effects of incomplete blocks due to provider skill level.

Equipment Challenges

Although ultrasound has largely replaced nerve stimulation for regional anesthesia in many HICs, access to both ultrasound and nerve stimulator units in many LMICs remains limited.

In some LMICs, access to ultrasound can often be surprisingly easier than access to nerve stimulators. This is due to decreasing costs, high turnover of ultrasounds in HICs over the past 10 years, and the high utility and versatility of ultrasounds machines throughout the hospital. Nonetheless, cost is still a significant barrier, as ultrasound units can range in price from $2,000 to over $50,000, while nerve stimulators generally cost several hundred dollars. In resource-constrained settings, expensive equipment, whether donated or procured, is often locked in secure storage for fear of theft, thereby limiting its utility even when technically available on site.

An additional barrier limiting access to ultrasound and nerve stimulators in many settings is the lack of supply chain and biomedical support. When equipment fails, repairs can be costly or may not even be feasible. When deploying relatively expensive and complex technologies such as ultrasound, access to biomedical support is essential and must be part of the procurement plan. Companies that have in-country or regional technical support should be considered, and donors should adhere to World Health Organization (WHO) Equipment Donation Guidelines to avoid unintended consequences of their efforts.

In the case of nerve stimulators, cost and availability of specialized, insulated needles can be prohibitive. Because improvisation using a noninsulated needle can be undertaken with many blocks, nerve stimulators still have a significant role in many resource-limited settings. Where sterile probe covers and sterile ultrasound gel are lacking (as discussed in the following), the use of nerve stimulation may provide for easier infection control over ultrasound guided regional. In addition, substitution of nerve stimulators designed for regional anesthesia with those designed for other purposes (e.g., neuromuscular blockade twitch monitoring) can be dangerous. Inability to precisely control milliamp output and dispersion can significantly increase the risk of nerve injury or block failure.

Not all ultrasounds are created equally when it comes to regional anesthesia in LMICs. Power supplies may not be compatible (110 to 240 V), and probe types may not be optimal. Where power is unreliable and battery operation is critical, special attention must be given to the wide-ranging battery performance among ultrasound units.

Although linear probes with higher frequencies are considered optimal for regional anesthesia (see Chapter 9 ), many blocks can surprisingly be accomplished with a wide variety of probes. Decreasing costs and replacement of older equipment by newer technology in HICs will continue to increase the prevalence of ultrasound, especially in LICs. Despite increased access to ultrasound, proficiency with nerve stimulation and landmark-based regional anesthesia techniques remains important for all anesthesiologists.

One of the most important pieces of equipment required to perform safe regional anesthesia may be a monitoring device. Monitors are perhaps more important, but they are equally as rare as ultrasounds in many LICs. Monitoring standards from HICs may not be feasible for many practice settings in LMICs. Without availability of these devices, the ability to provide safe anesthesia of any sort (including regional) may be limited. Additional safety equipment that must not be overlooked includes intravenous access supplies, vasopressors, and airway equipment to deal with emergencies.