Teachings in Peripheral Nerve Blocks

Peripheral nerve blocks are cost-effective anesthetic techniques used to provide superb anesthesia and analgesia, while avoiding airway instrumentation and the hemodynamic consequences of general and neuraxial anesthesia. Patient satisfaction, a growing demand for cost-effective anesthesia, and a favorable postoperative recovery profile have all resulted in a growing demand for regional anesthesia. Although there are relatively few published reports of serious complications associated with the use peripheral nerve blocks, the risk of complications is real and the consequences can be catastrophic. Therefore, just as with any other medical procedure, proper training is a prerequisite for the successful and safe implementation of nerve blocks. Indeed, many researchers attribute the complications commonly associated with the use of regional anesthesia to a lack of appropriate training and exposure to the techniques during the residency training program. In this chapter, we outline the current training requirements in regional anesthesia in United States, discuss their drawbacks, and suggest a model for a structured and effective training.

Anesthesiology education has seen a number of changes in the past decade. A third year of training in clinical anesthesia has been added, and significant emphasis is placed on the development of and training in anesthesiology subspecialties, such as cardio-thoracic anesthesia, obstetric anesthesia, neuroanesthesia, ambulatory anesthesia, and pain management. Similarly, the subspecialty of regional anesthesia has entered a renaissance. The number of high-quality scientific publications in regional anesthesia has significantly grown over the past decade, and new techniques and procedures have been introduced. There has also been a remarkable increase in the awareness of the advantages of regional anesthesia in a wide variety of clinical situations. However, although the Residency Review Committee (RRC) clearly specifies the training requirements for spinal and epidural anesthesia (50 epidural anesthetics, 50 spinal anesthetics), the current recommendations for training in peripheral nerve blocks remain vague and, perhaps, inadequate. These recommendations suggest that to achieve clinical competency, a trainee must perform 40 peripheral nerve blocks for surgical anesthesia and 25 for pain management. These recommendations do not specify which blocks should be in a core curriculum of training in anesthesia and, therefore, it is nearly impossible to ensure that residents graduating from different programs will have comparable degrees of expertise in all nerve block procedures. For instance, if a resident were to perform each of some 34 block techniques listed in Table 1 with an equal frequency (two blocks in each technique), he or she would actually surpass the RRC's training recommendations, and yet would not master any of the techniques specified.

There is ample evidence that current training in regional anesthesia leaves residents unprepared to implement the full breadth of regional anesthesia techniques. Almost two decades ago, it was suggested that large discrepancies existed in the use of regional anesthesia among training programs (2.8-55.7% of total delivered anesthetics), and that some anesthesiology residency programs were failing to teach regional anesthesia adequately. A report in 1993, suggested that the overall use of regional anesthesia had increased to almost 30%; however, the disparity among teaching programs persists. Several residents' surveys conducted nationally and internationally have established that the number of peripheral nerve blocks performed during residency is limited, and that residents lack confidence in their ability to perform such blocks. A survey of exposure to regional anesthesia techniques indicated that 51, 62, and 75% of the graduating residents may not be confident in performing interscalene, femoral, and sciatic blocks, respectively. These results are not surprising, as the survey also indicated that the residents surveyed had performed five or less of each block by the end of their residency training. Currently, there are well over 40 widely accepted peripheral nerve block procedures. It is unlikely that the exposure of trainees during their residency training program is sufficient to achieve clinical competency in all regional anesthesia procedures, particularly in specific peripheral nerve blocks. Unfortunately, there is little guidance for instructors as to how to teach modern regional anesthesia techniques and insufficient research on the educational methods that are directly relevant to postgraduate training in anesthesia.

The completion of an approved residency training program is generally accepted to equate that the graduate possess the skills and knowledge required to deliver state-of-the art, high-quality anesthesia care. However, whereas the American Board examination assesses the theoretical knowledge of a graduate, the objective grading of a candidate's procedural skills is lacking. An objective grading system has been recommended for epidural anesthesia and subjective criteria have been proposed to foster the cognitive and noncognitive maturation of residents. Two recent studies suggested that 60-90 procedures may be required before epidural anesthesia is mastered and a sufficiently high success rate is attained. A study by Kopacz et al. suggested that for the attainment and maintenance of a 90% success rate, 45 and 60 attempts at spinal and epidural anesthesia are required, respectively. It would seem unrealistic that trainees can acquire reciprocal proficiency with fewer peripheral nerve block procedures, which are often much more complex than neuraxial anesthesia.

The learning curve and the number of procedures required before achieving adequate technical skill have been the subject of studies in other medical disciplines. For example, Cass et al. concluded that supervision of the initial 50 and performance of a subsequent 100 upper and lower gastrointestinal endoscopies are necessary to achieve clinical competence (defined as a 90% success rate). Family practice residents and untrained family practitioners have been shown to require 25 supervised attempts at performing flexible fiberoptic sigmoidoscopy to attain proficiency comparable with that of experienced practitioners [13]. Duong and Havel [14] concluded that 20-30 cases are required to achieve satisfactory skill in managing cardiac anesthesia patients. Many experts would agree that after performing only 30 endotracheal intubations by the conclusion of the residency program, few residents would be adequately trained to perform intubations with an acceptable degree of safety and reliability. It is quite clear that the current training recommendations do not translate into an assurance that anesthesiology graduates have acquired sufficient expertise in regional anesthesia procedures, particularly in peripheral nerve blocks.

Defining the end points that qualify an anesthesiologist as competent in the performance of regional anesthesia techniques is difficult. An indicator of the difficulty of learning regional anesthesia techniques is the finding of Kopacz et al. [10] that each trainee should be required to perform at least 45 spinal and 60 epidural anesthetics to achieve competency (i.e., a 90% success rate). No methods exist that can reliably predict the eventual performance of the skills required in anesthesiology, and such assessments of technical performance are often unreliable at best. Whereas written in-training examinations are reliable at assessing a resident's fundamental knowledge of anesthesiology principles, they are obviously inadequate for assessing physical skills. The current American Board of Anesthesiology method of logging the number of procedures performed (in-training reports) ignores the assessment of quality. Simply performing a given procedure a certain number of times does not ensure that the procedure has been learned or performed well. Direct observation without criteria, currently used in many training programs, clearly lacks reliability.

residency, which translates into clinical competency in performing basic nerve blocks. Our residents perform between 100 and 250 nerve block procedures by the end of their residency training. Since most of these are basic and intermediate blocks, they are capable of practicing peripheral nerve blocks for a wide spectrum of surgical indications upon graduation.

In a regional anesthesia training model at St Luke's-Roosevelt Hospital, New York, every resident is required to master basic nerve block techniques during the first 2 years of clinical training. Sizeable orthopedic, hand, foot, and vascular surgery volumes, combined with the routine use of regional anesthesia for a majority of these procedures, allows a sufficient number of procedures for residents to achieve adequate proficiency in basic regional anesthesia techniques during their first 2 clinical years of anesthesia training. As the entire staff is proficient at performing most basic and many of the intermediate block techniques, by the time they reach their senior year of training, most trainees become proficient in the use of basic techniques, the pharmacology of local anesthetics, and principles of nerve stimulation.

Senior residents in their last year of training are then assigned to a 2-month rotation in advanced regional anesthesia, during which time, they are instructed in intermediate and advanced regional anesthesia techniques (e.g., lumbar plexus blocks, continuous blocks, etc.). We find that a concentrated training in regional anesthesia during a designated month is much more effective in our setting than a daily "designated block resident" model suggested by other training programs. The main disadvantage of such "nerve block rotation" is that someone else does the perioperative management, thus preventing the resident who performs the blocks to conduct the regional anesthetic from the beginning to the end. However, it is the perioperative (especially intraoperative) management that largely determines the success of any regional anesthetic.

During a month-long concentrated training in the regional anesthesia rotation, the residents typically perform and perioperatively manage an additional 20-30 advanced nerve block procedures. As these residents are already well trained in all of the basic and some intermediate nerve block procedures, as well as the pharmacology of local anesthetics, before their regional anesthesia rotation, they are able to acquire new techniques at an accelerated pace.

All staff members provide training in the basic regional anesthesia skills in our anesthesia residency training. The ample opportunity to practice regional anesthesia and the mentoring available to our faculty members ensures that almost all attending staff are proficient in basic regional anesthesia techniques. However, training in advanced regional anesthesia techniques is conducted by a core team of regional anesthesiologists who have completed a fellowship or possess substantial expertise in practicing and teaching regional anesthesia. This organization is of crucial importance to ensure the quality training of residents. To advance the subspecialty, it is important that we, as a profession, ensure the adequate education of a number of regional anesthesiologists through structured fellowship programs.

Nearly all major conduction blocks in our training program are performed using insulated nerve block needles with the aid of a nerve stimulator. The elicitation of specific and objective responses to nerve stimulation during block performance not only adds significant educational value for the trainees, but also allows for patient sedation, which makes teaching more acceptable to patients. In addition, the use of a hand-free, foot-controlled nerve stimulator in our practice allows instructors to teach residents simultaneously during the block performance and to control the current output of the nerve stimulator without the need for additional personal to operate the nerve stimulator.

In recent years, a number of excellent texts, multimedia teaching programs, and other tools for teaching regional anesthesia have been developed. There are several mannequins, CD-ROMs, and web sites that can be used to aid the learning of regional anesthesia techniques. Virtual reality simulators for training in regional anesthesia are also likely to become available in the future. In our residency program, all residents receive an institutional regional anesthesia rotation manual. They are also provided with access to the Internet at a number of locations in the department. That way, the residents simply print out the technique(s) description off the www.nysora.com website and read about the blocks they are about to perform.

In summary, most anesthesiologists clearly perceive a need to employ more peripheral nerve blocks in their practice, and we predict that the use of peripheral nerve blocks will increase in the future. A similar trend has been seen in Europe, where, for example, French anesthesiologists utilize regional anesthesia in 23% of their cases, a 14-fold increase in comparison with the amount of regional anesthesia practiced in 1980. However, it has been well-established that the current teaching and requirements for the training of regional anesthesia is suboptimal. A structured regional anesthesia rotation, a well-defined training curriculum, a dedicated team of mentors with training in regional anesthesia, and ample clinical volume are all prerequisites for the adequate training of residents. A core group of widely applicable and relatively simple nerve blocks (basic and more common intermediate nerve blocks) should be mastered by all graduates to achieve more consistent proficiency in these techniques by the graduating residents.

Table 1.The New York School of Regional Anesthesia classification of regional anesthesia procedures

Table 2.The New York School of Regional Anesthesia classification of regional anesthesia procedures: Definition

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