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Anesth Analg 2002;94:71-76
© 2002 International Anesthesia Research Society

AMBULATORY ANESTHESIA

Peripheral Nerve Blockade with Long-Acting Local Anesthetics: A Survey of The Society for Ambulatory Anesthesia

Stephen M. Klein, MD, Ricardo Pietrobon, MD*, Karen C. Nielsen, MD, David S. Warner, MD, Roy A. Greengrass, MD FRCP, and Susan M. Steele, MD

Departments of Anesthesiology and *Surgery, Duke University Medical Center, Durham, North Carolina

Address correspondence to Stephen M. Klein, MD, Department of Anesthesiology, Box 3094, Duke University Medical Center, Durham, NC 27710. Address e-mail to klein006{at}mc.duke.edu


   Abstract
Top
 Abstract
Introduction
 Methods
 Results
 Discussion
 References
 
Despite the growth of ambulatory anesthesia and the renewed popularity of regional techniques, there is little current information concerning outpatient regional anesthesia practices or attitudes about discharge with an insensate extremity. We present results from a survey sent to all members of the Society for Ambulatory Anesthesia (SAMBA). The survey was mailed in January 2001 to 2373 SAMBA members, along with a self-addressed stamped return envelope. After 3 mo, 1078 surveys were returned (response rate 45%). Respondents indicated that they were most likely to perform axillary (77%), interscalene (67%), and ankle blocks (68%) on ambulatory patients. They were less likely to perform lower extremity conduction blocks in ambulatory patients (femoral blocks, 40%; all other types of blocks, <23%]. Eighty-five percent of respondents discharged patients with long-acting blocks, but this was mainly limited to three types. Of the 16% who never or rarely discharged patients with long-acting blocks, the primary reasons were concern about patient injury (49%) and the inability for patients to care for themselves (28%). Only 22% of office-based anesthesiologists would perform upper extremity blocks and only 28% would perform lower extremity blocks (P < 0.001). This survey demonstrates that use of regional anesthesia in outpatients is common but restricted to a few techniques. Discharge with an insensate upper extremity is prevalent but discharge with an insensate lower extremity is not common and remains controversial. Despite the reasoning for the reported practices, randomized data are necessary to confirm the validity of these concerns.

IMPLICATIONS: This survey demonstrates that use of regional anesthesia in outpatients is common but restricted to a few techniques. Discharge with an insensate upper extremity is common but discharge with an insensate lower extremity is not prevalent and remains controversial.


   Introduction
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 Abstract
 Introduction
Methods
 Results
 Discussion
 References
 
Peripheral nerve blockade has become increasingly popular because it provides excellent surgical anesthesia and postoperative analgesia. At the same time, ambulatory anesthesia has become commonplace and constitutes the majority of practice in the United States (1). Despite the perceived popularity of regional anesthesia and its potential benefits, current detailed information about outpatient practices is not available. In particular, attitudes and concerns of anesthesiologists about discharging patients with a long-acting peripheral nerve block are unknown.

Discharging patients with an insensate extremity remains controversial. Long-acting blockade provides excellent anesthesia but also leads to a loss of proprioception and the protective reflex of pain. Because of this, there is concern that an insensate extremity may place outpatients at risk for accidental injury or create difficulty with activities of daily living when their limb is anesthetized. Patients with lower extremity peripheral nerve blockade are also potentially at risk for falls and the inability to ambulate.

Surgeons often complain that patient satisfaction with their analgesia is reduced when long-acting nerve blocks resolve at home or at night when there are few treatments for refractory pain. Long-acting local anesthetics also have the disadvantage of extended onset time, which may be a drawback for rapid turnover in an ambulatory center. As a result, physicians may restrict the use of long-acting local anesthetics in the ambulatory setting or avoid their use in the lower extremity.

To determine the frequency of peripheral nerve blockade use in the ambulatory setting and define the concerns and attitudes of anesthesiologists toward discharging patients with long-acting nerve blocks, we conducted a survey that was sent to all members of the Society for Ambulatory Anesthesia (SAMBA). The survey was specifically designed to document which peripheral nerve blocks are commonly performed with long-acting local anesthetics in outpatients. For anesthesiologists who choose not to perform these blocks we sought to identify their reasons for avoiding this practice.


   Methods
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 Abstract
 Introduction
 Methods
Results
 Discussion
 References
 
A survey was adapted from a survey by Hadzic et al. (2) who queried members of the ASA and the American Society of Regional Anesthesia (ASRA) 5 yr ago on a similar subject.

The active SAMBA mailing list was obtained from the society with permission to contact its members. All members were included. This included attending anesthesiologists, fellows, residents, affiliates, and retirees. Respondents who indicated an inability to complete the survey were excluded. Before distribution, a response rate of <40% rate was set for initiation of a second follow-up questionnaire to increase response rate. The survey (Fig. 1) was mailed in January 2001 to 2373 members, along with a self-addressed stamped return envelope. There was no monetary compensation provided. After 3 mo the initial response rate was 45%. As a result the project was halted on March 31, 2001 and a second questionnaire was not mailed. All data were collected without any personal identifiers from the respondents.



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  		Figure 1. Questionnaire sent to all members of the Society for Ambulatory Anesthesia.

 
Survey responses were reviewed and entered into a computerized database. Descriptive statistics were used to summarize the responses to all questions. Differences in group demographic characteristics were tested by {chi}2 test for categorical measures. Results were considered significant at the 95% confidence level. Analysis of variance (ANOVA) with a Bonferroni correction was used when making multiple comparisons. Results were calculated using Stata version 7.0 Statistical Software (Stata Corporation, College Station, TX).


   Results
Top
 Abstract
 Introduction
 Methods
 Results
Discussion
 References
 
There where 2373 surveys mailed and 1078 returned, constituting a 45% response rate. Sixty-one surveys were not included in the response rate: 35 were returned because of an incorrect address and 26 were marked retired and not completed.

When respondents were asked which peripheral nerve blocks they were willing to perform on ambulatory patients, upper extremity blocks (87% of respondents) were more commonly performed than lower extremity blocks (77% of respondents). Of those who indicated using upper extremity blocks, axillary (77%) and interscalene (67%) were by far the most prevalent (Fig. 2). All other types of blocks were used by <23% of the respondents. Among those willing to perform lower extremity blocks in ambulatory patients, the most common were ankle (68%) and femoral blocks (40%) (Fig. 2). All other types of blocks were used by <21% of respondents. Most respondents were likely to perform both upper and lower extremity blocks (P < 0.001). The willingness to perform certain blocks was related; respondents were unlikely to perform lower extremity blocks without performing upper extremity blocks.



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  		Figure 2. Frequency of peripheral nerve blockade performed by members of the Society for Ambulatory Anesthesia. Horizontal bars represent percentages of respondents who indicated that they perform the indicated techniques on ambulatory patients.

 
When asked about discharging patients with long-acting blocks, "never" was indicated by 7%, "often" by 29%, "rarely" by 9%, and "routinely" by 56%. However, the types of blocks they were willing to perform were usually limited to the three most common (axillary, interscalene, and ankle) (Fig. 3). Of the 172 (16%) who never or rarely discharged patients with long-acting blocks, the primary reasons were concern about patient injury (49%) and the inability for patients to care for themselves (28%) (Fig. 4). The next most common reasons were surgical preference (19%) and the lack of advantage over other techniques (17%).



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  		Figure 3. Frequency of peripheral nerve blockade with long-acting local anesthetics performed by members of the Society for Ambulatory Anesthesia. Horizontal bars represent percentages of respondents who indicated that they "routinely" or "often" use long-acting local anesthetics and were willing to perform the indicated techniques in the ambulatory setting.

 


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  		Figure 4. Primary reasons given for avoiding the use of long-acting local anesthetics in the ambulatory setting. Horizontal bars represent percentages of those respondents who indicated that they "never" or "rarely" perform the indicated techniques with a long-acting local anesthetic in the ambulatory setting.

 
Of those who were willing to perform blocks with long-acting local anesthetics in the ambulatory setting and answered "yes," "routinely," or "often" (85% combined), their practice pattern with long-acting local anesthetics (Fig. 3) paralleled the types of blocks they were likely to perform (Fig. 2). However, for each type of block the numbers were smaller (Fig. 3).

When stratified by age, several types of block were associated with certain age categories (Fig. 5). Those most likely to send patients home after long-acting blockade were anesthesiologists <40 yr old (P = 0.017). Those between 40 and 49 yr were more likely to work at ambulatory institutions than in other practice settings (P = 0.006) (Fig. 6). Those whose practice comprised less than <10% regional anesthesia were less likely to perform any type of block (P < 0.001).



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  		Figure 5. Incidence of anesthesiologists performing individual blocks by age. Horizontal bars represent the percentages of respondents willing to perform the indicated techniques stratified by age grouping (*P < 0.002; **P < 0.05).

 


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  		Figure 6. Practice locations of anesthesiologists based on their indicated age. Vertical bars represent the percentages of respondents who indicated their practice location stratified by age grouping (*P < 0.05)

 
When compared by place of work, anesthesiologists practicing office-based anesthesia were least likely to perform blocks in general. Only 22% of office-based anesthesiologists would perform upper extremity blocks and only 28% would perform lower extremity blocks (P < 0.001). Those indicating an ambulatory practice were not more likely to perform individual blocks (P = 0.698); however, when they did blocks, they were more likely to discharge patients home after using long-acting local anesthetics (P = 0.018). Of note, those working in a teaching hospital were more likely to perform sciatic blocks (19%) compared with those working at a nonteaching hospital (8%, P < 0.001).


   Discussion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
References
 
This survey represents the largest sample of ambulatory anesthesiologists and their regional anesthesia practice that we know of. The results demonstrate that anesthesiologists (members of SAMBA) commonly place two types of upper extremity blocks and two types of lower extremity blocks in the ambulatory setting. In particular, there is widespread use of the axillary (77%) and interscalene (67%) approaches as well as use of the ankle block (68%) and, less so, the femoral (40%). The data also confirm that anesthesiologists’ discharge patterns closely correlate with which blocks they use in practice. Anesthesiologists are willing to discharge patients with an insensate upper extremity block (axillary and interscalene) but are hesitant to do so with a lower extremity block (excluding ankle blocks). Of those who restrict the use of long-acting local anesthetic in the ambulatory setting, the primary reasons given were fear of injury or difficulty with activities of daily living. Surprisingly, few cited onset or preparation time.

Using axillary (77%) and interscalene (67%) upper extremity blocks in outpatients continues to be the most prevalent outpatient peripheral nerve block. This trend has been relatively constant for axillary blocks over the last five years (2). This likely reflects the utility of the axillary block to anesthetize the majority of the upper extremity, the prevalence of hand surgery and the emphasis on axillary techniques in training programs. In fact, in a survey of US anesthesia residents, CA-3 residents reported performing nearly twice as many axillary blocks compared with most other peripheral nerve blocks (3). However, this number (20 blocks) was remarkably small, given the frequent use in practice documented in this survey.

However, data from this study indicate an increase of nearly 25% in the use of interscalene blocks compared with that reported by Hadzic et al. (2), who reported a 42% use just five years ago. In the study by Hadzic et al. (2) 43.6% of respondents believed that use of peripheral nerve blocks would increase. Of additional interest, 67% of SAMBA respondents used interscalene blocks in their practice but nearly 51% of CA-3 residents were not confident performing this block at the end of their residency just three years ago (3). Given the ability to provide anesthesia for nearly all procedures of the upper extremity with axillary and interscalene blocks and the widespread use in clinical practice, more emphasis at the residency training level may be warranted.

Data from this study also demonstrate that use of major conduction blocks of the lower extremity remains relatively infrequent. The explanations for this are likely multifactorial. Concern for ambulation may be a reason in avoiding these techniques. However, perceptions that lower extremity blocks are technically more difficult and the need for more than one block to anesthetize the entire extremity may also contribute to the decision. Compounding this is the alternative option to substitute neuraxial techniques, which were not addressed in this survey. Neuraxial blocks are usually perceived to be faster to perform but do not provide the same degree of postoperative pain relief.

These trends also parallel the exposure of residents during training to lower extremity blocks. In this SAMBA survey, only 40% of respondents used femoral blocks in their practice and only 12% performed sciatic blockade. This corresponds to the study by Smith et al. (3), who found that 62% of CA-3 residents were not confident performing a femoral block and 75% were not confident performing a sciatic block.

The percentage of respondents discharging patients using long-acting blocks was surprisingly large. Despite frequent perceptions that anesthesiologists avoid this practice, nearly 85% of respondents stated that they "often" or "routinely" discharged patients after a long-acting block. This frequent response, however, was primarily restricted to the three most popular blocks (axillary, interscalene, and ankle). These are all sites that can readily be immobilized and have limited impact on ambulation. Respondents were much less likely to use long-acting local anesthetic for the major conduction blocks of the lower extremity, demonstrating that the ability to ambulate is still a major concern for practitioners. This was further illustrated by the fact that respondents cited that concern for patient injury (i.e., fall, accidental limb, or nerve trauma) (49%) and the inability for patients to care for themselves (28%) were reasons for avoiding prolonged blockade. Issues such as concern for pain with sudden block resolution and logistics were not major factors.

Trends among different demographic groups and practice settings were surprisingly homogenous. This likely reflects similar practice patterns in those belonging to SAMBA. However, one area where this similarity was not apparent was for those in office-based practice. This group was least likely to use regional anesthesia as well as long-acting local anesthetics (P < 0.001). The reasons why this group would respond differently than those in ambulatory practice, who also care for an outpatient population, were not addressed. However, this may reflect a difference in case mix or the lack of additional resources for assistance.

Younger anesthesiologists were more likely to use long-acting local anesthetics and perform more of the major conduction blocks. The significance of this finding is unclear; however, it appears to conflict with the numerically small experience and lack of confidence identified in residency teaching by Smith et al. (3). One might speculate that this reflects a new trend in residency education, an abandonment of certain techniques by older respondents, or perhaps a more aggressive practice by less senior practitioners.

One of the limitations in this study design was the failure to specifically define the frequency terms "often" and "rarely." As a result, the exact incidence of blockade is difficult to define. In addition, detailed information about the concerns of those who do send patients home with an insensate extremity but avoid certain approaches were not queried.

Five years ago Hadzic et al. (2) documented regional anesthesia practices in a subset of the ASA and ASRA membership. Information about discharge with long-acting local anesthetics was not obtained. In this study, we attempted to confirm the use of peripheral nerve blocks in ambulatory patients and determine if practice has changed given the resurgence in regional anesthesia. More importantly, by questioning an entire subspecialty group, we sought to define outpatient practices and document attitudes and concerns about discharging patients with a long-acting peripheral nerve block. With this information we hope to refine future research to address these issues.

In summary, the results of this survey demonstrate that use of regional anesthesia in outpatients is common but restricted to a few techniques. Further, discharge with an insensate upper extremity is frequent. Discharge with an insensate lower extremity is not prevalent and remains controversial. Despite the reasoning elicited in this survey, randomized data are necessary to confirm the validity of these concerns.


   References
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 

  1. Mezei G, Chung F. Return hospital visits and hospital readmissions after ambulatory surgery. Ann Surg 1999; 230: 721–31.[ISI][Medline]
  2. Hadzic A, Vloka J, Kuroda M, et al. The practice of peripheral nerve blocks in the United States: a national survey. Reg Anesth Pain Med 1998; 23: 241–6.[ISI][Medline]
  3. Smith M, Sprung J, Zura A, et al. A survey of exposure to regional anesthesia techniques inAm anesthesia residency training programs. Reg Anesth Pain Med 1999; 24: 11–6.[ISI][Medline]
Accepted for publication September 4, 2001.




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Lippincott, Williams & Wilkins Anesthesia & Analgesia® is published for the International Anesthesia Research Society® by Lippincott Williams & Wilkins with the assistance of Stanford University Libraries' HighWire Press®. Copyright 2006 by the International Anesthesia Research Society. Online ISSN: 1526-7598   Print ISSN: 0003-2999 HighWire Press