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Key words: Pain: acute; perioperative. Practice guidelines: acute pain management.
Practice guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints.
Practice guidelines are not intended as standards or absolute requirements. The use of practice guidelines cannot guarantee any specific outcome. Practice guidelines are subject to revision from time to time, as warranted by the evolution of medical knowledge, technology, and practice. The guidelines provide basic recommendations that are supported by analysis of the current literature and by a synthesis of expert opinion, open forum commentary, and clinical feasibility data (Appendix).
A. Definition of Acute Pain in the Perioperative Setting
Acute pain in the perioperative setting has not been specifically defined in the available literature. The Task Force has not given preference to literature based on any particular system of definition or classification. For these guidelines, acute pain in the perioperative setting is defined as pain that is present in a surgical patient because of preexisting disease, the surgical procedure (e.g., associated drains, chest or nasogastric tubes, complications), or a combination of disease-related and procedure-related sources.
B. Purpose of Guidelines for Acute Pain Management in the Perioperative Setting
The purpose of these guidelines is to facilitate the efficacy and safety of acute pain management in the perioperative setting and to reduce the risk of adverse outcomes. A number of adverse outcomes can result from undertreatment of postoperative pain. These include (but are not limited to) thromboembolic and pulmonary complications, extension of time spent in an intensive care unit and/or in a hospital, and reduced patient satisfaction. The principal adverse outcomes associated with management of perioperative pain include (but are not limited to) respiratory depression, brain injury, other neurologic injury, sedation, circulatory depression, nausea and/or vomiting, impairment of bowel function, pruritus, and urinary retention.
These guidelines focus on modalities of perioperative pain management that require a higher level of expertise and organizational structure than "as needed" intramuscular or intravenous injections of opioids and that generally provide more effective relief of pain. Examples include (but are not limited to) epidural (and intrathecal) analgesia (EA), intravenous patient-controlled analgesia (PCA), and a number of regional analgesic (RA) techniques. The guidelines are not intended as an exhaustive or detailed consideration of specific techniques or all possible approaches.
The specialty of anesthesiology brings an exceptional level of interest and expertise to the area of perioperative pain management. As a consequence, the anesthesiologist is in a unique position to provide leadership in integrating pain management into other aspects of perioperative care and thus improve this area of practice. In this leadership role, the anesthesiologist can contribute further to quality of care by developing and directing institution-wide perioperative analgesia programs that include collaboration with and participation by others, when appropriate.
The role of anesthesiologists in managing acute pain extends beyond the perioperative setting. Patients with severe or concurrent medical illness such as sickle cell crisis, pancreatitis, or acute pain related to cancer or cancer treatment also benefit from aggressive pain control. Labor pain is another condition of interest to anesthesiologists. However, the complex interactions of concurrent medical therapies and physiologic alterations make it impractical to address pain management for these populations within the context of this document.
These guidelines focus on management of acute pain in the perioperative setting for adult (including geriatric) and pediatric patients. The guidelines apply to inpatient and outpatient surgery. These guidelines are intended for use by anesthesiologists or by individuals who deliver care under the supervision of anesthesiologists.
Evidence to support each guideline was carefully sought. The search included a comprehensive review of the published literature, surveys of the opinions of a large panel of consultants with expertise in acute pain management, and the opinions of the members of the Task Force. An indication of the strength of the evidence supporting each guideline is provided.
I. Proactive Planning
The Task Force defines proactive planning as a process of integrating pain management into the perioperative care of patients. The literature, the panel of consultants, and the Task Force members strongly support the use of proactive planning for postoperative pain management. This support is based on recognized associations between preoperative and intraoperative analgesic techniques for the reduction of pain in the postoperative period.
Recommendations: An individualized proactive plan (e.g., a predetermined strategy for postoperative analgesia) should be considered for all surgical patients. Factors that may influence the formulation of a proactive plan include (but are not limited to) type of surgery and expected severity of postoperative pain, underlying medical conditions (e.g., presence of respiratory or cardiac disease, allergies), the risk-benefit ratio of the techniques available, and patients' preferences and/or previous experience with pain. Proactive planning of perioperative pain should be part of the preoperative evaluation by the anesthesiologist and, in collaboration with others (e.g., nurses, surgeons, pharmacists), should be part of an institution's general plan for patient care.
Activities that are commonly encompassed by proactive planning include (but are not limited to) (1) obtaining a pain history based on patients' experiences, (2) preoperative pain therapy when appropriate and feasible, (3) intraoperative procedures (e.g., wound infiltration) when appropriate and feasible, and (4) intraoperative or postincisional preparation of patients for postoperative pain management (e.g., initiating EA administration before the completion of surgery). Any treatment plan requires regular assessment and refinement based on the changing responses of individual patients.
II. Education and Training of Hospital Personnel
The available literature suggests that training and experience of hospital personnel (e.g. nurses, house-officers, pharmacists, psychologists) may be helpful in reduction of risk. There is strong agreement among the panel of consultants and the Task Force members that such education, training, and experience also contribute to improved quality of care.
Recommendations: Anesthesiologists offering perioperative analgesia services should provide, in collaboration with others as appropriate, ongoing education and training to ensure that hospital personnel are knowledgeable and skilled with regard to the effective and safe use of the available treatment options within the institution. The scope of education should include topics ranging from basic bedside skills for evaluation of acute pain to an understanding of sophisticated pharmacologic techniques (e.g., PCA, EA, and various RA techniques) and nonpharmacologic techniques (e.g., relaxation, imagery, hypnotic methods). The need for education and training is ongoing as new personnel enter an institution and as modifications in therapeutic approaches are made.
III. Education and Participation of Patients and Families in Perioperative Pain Control
The panel of consultants and the Task Force members regard the concept of education of patients and families in planning and participation in perioperative pain control as being important to their comfort and well-being.
Recommendations: Anesthesiologists offering perioperative analgesia services should provide, in collaboration with others as appropriate, education to patients and families regarding their roles in achieving comfort, reporting pain, and using the recommended analgesic methods to optimal benefit. Common misconceptions about the risk of side effects and addiction should be dispelled. Educational methods that facilitate optimal care of patients using PCA and other sophisticated methods might include (but are not limited to) discussion of analgesic methods at the time of the pre-anesthetic evaluation, brochures and video tapes to educate patients about therapeutic options, and discussion at the bedside during postoperative visits.
IV. Assessment and Documentation of Perioperative Pain Management
The panel of consultants and the Task Force members strongly support the concept of assessment and documentation of response to perioperative pain therapy as important to effective care. Unless the response to pain therapy is regularly evaluated, there is no basis for rational, individualized therapy.
Recommendations: Anesthesiologists offering perioperative analgesia services should use, in collaboration with others as appropriate, pain assessment instruments to facilitate the regular evaluation and documentation of pain, the effects of pain therapy, and side effects caused by the therapy (Table 1and Table 6templates 1 and 6).
V. 24-Hour Availability of Anesthesiologists
The panel of consultants and the Task Force members support the concept of 24-hour availability of anesthesiologists providing perioperative pain management as being important for maximizing patient comfort and safety. The condition of patients after surgery is frequently dynamic, and analgesic needs may change at any time.
Recommendations: Most analgesic techniques place patients at some risk for side effects of complications that require prompt medical evaluation. Anesthesiologists responsible for perioperative analgesia, in collaboration with others as appropriate, should be available at all times to consult with ward nurses, surgeons, or other involved physicians and assist in evaluating patients who are experiencing problems with any aspect of postoperative pain relief.
VI. Use of Standardized Institutional Policies and Procedures for Ordering, Administering, Discontinuing, and Transferring Responsibility for Perioperative Pain Management
The available literature suggests that institutional protocols and procedures for ordering, administering, discontinuing, and transferring responsibility for pain management are helpful in providing effective and continuous pain control. The Task Force regards the use of institutional policies and procedures as a logical part of interdisciplinary management of perioperative pain, and there is strong agreement from the panel of consultants that this approach is beneficial. The development of hospital-wide policies and procedures helps standardize clinical practice using techniques such as PCA, EA, and various RA techniques (Table 2and Table 3templates 2 and 3). Standardization promotes safety and creates a framework for customization of care. Routine use of bedside documentation encourages caregivers to continually reevaluate pain treatment and respond to inadequate therapy in a timely manner. Daily evaluation, planning, and written documentation by those who are medically responsible for pain relief help establish the importance of a formal and structured approach to pain management (Table 4, Table 5, Table 6, Table 7templates 4-7).
Recommendations: Anesthesiologists offering perioperative analgesia services should participate in developing, in collaboration with others as appropriate (especially nurses), standardized institutional policies and procedures for ordering, administering, discontinuing, and transferring responsibility for postoperative pain management. Policies (the foundation or "ground rules" for practice) and procedures (outlining the "how to" aspects of applying policies to patient care) should be readily available on each patient care unit. The polices and procedures also serve as ongoing educational and informational references.
VII. Use of Three Specific Techniques for Perioperative Pain Management
The literature strongly supports the efficacy and safety of three techniques used by anesthesiologists for the control of pain in the perioperative setting: (1) PCA with systemic opioids, (2) EA with opioids or opioid/local anesthetic mixtures (or intrathecal opioids), and (3) RA techniques, including (but not limited to) intercostal blocks, plexus infusions, and local anesthetic infiltration of incisions. The literature indicates that these three techniques used by anesthesiologists have no higher incidence of side effects than less effective techniques for perioperative pain management. The panel of consultants and the Task Force members strongly support the use of PCA, EA, and RA by anesthesiologists when appropriate and feasible.
Recommendations: To meet the diverse needs of individual patients, anesthesiologists who manage perioperative pain should make available as appropriate a variety of effective therapeutic options such as PCA, EA, and RA.
VIII. A Multimodality Approach to Perioperative Pain Management
During the administration of anesthetics for surgery, the needs of many patients may best be met by taking advantage of the combined effects of a number of agents. Similarly, there is growing conviction that a multimodality approach (i.e., two or more analgesic agents or techniques used in combination) to providing postoperative analgesia has advantages over the use of a single modality.
The literature supports the efficacy of two or more analgesic techniques (including nonpharmacologic methods) used in combination for the control of perioperative pain, especially when different sites and/or mechanisms of action are involved and/or when synergy of effect is achieved. In addition, the literature indicates that multimodality approaches are associated with side effects no greater than those resulting from single analgesic techniques for perioperative pain management. The panel of consultants and the Task Force members support the use of multimodality techniques when appropriate and feasible.
Recommendations: Anesthesiologists managing perioperative pain should make available as appropriate a variety of analgesic techniques and should consider their use in combination under appropriate circumstances.
IX. An Organized Interdisciplinary Approach to Perioperative Pain Management
Although dedicated individuals can improve perioperative pain control for the individual patients they treat, comprehensive programs provide optimal analgesia throughout an institution. Such programs have been advocated by national and international pain specialty societies [1,2]and the Federal government.* The Task Force strongly believes that, based on training, knowledge, skills, interest, and historical innovation, anesthesiologists are uniquely qualified to provide leadership within their institutions in developing and managing perioperative pain management programs.
The panel of consultants and the Task Force members regard organized interdisciplinary activities (e.g., anesthesiologists in collaboration with nurses, surgeons, and pharmacists) as important and optimal in providing effective, safe, and continuous perioperative pain control (Table 8template 8). An essential feature of such an approach should be an ongoing strong working relationship between anesthesiologists and nurses.
Recommendations: Anesthesiologists who manage perioperative pain should develop (in collaboration with nurses, surgeons, pharmacists, and others) an organized, interdisciplinary approach to perioperative pain management within their institutions.
X. Recognition and Management of Special Features of Pediatric Perioperative Pain Management
Pediatric patients (infants and children) present unique problems regarding perioperative pain management for reasons that include differences in the perception of care-givers regarding the need for analgesia, differences in the pharmacology of analgesic medications when used in this group, and the strong emotional components of pain in children. In the past, safe methods for providing analgesia have been underused in pediatric patients because of fear of opioid-induced respiratory depression.
The emotional component of pain is very strong in children. Absence of parents, security objects, and familiar surroundings may be perceived by the child to be as painful as the surgical incision. When clear evidence of physical pain is not seen, the tendency of health-care providers is to assume pain is not present and therefore defer treatment. In addition, young childrens' fear of injections makes intramuscular opioids or other methods, which themselves cause discomfort, less acceptable to this group than to adults. Many children will choose to suffer in silence knowing that an expression of pain will result in a dreaded injection.
Pain assessment is more difficult in children because, as they grow and develop, cognitive and emotional responses are different from adults and are constantly changing. Special instruments are available to assist young children in self-reporting of pain, and behavioral and physiologic parameters can be employed to assess preverbal children or in those who cannot self-report.
The literature strongly supports the effectiveness of a variety of techniques in providing analgesia in pediatric patients. Many of these are the same techniques used in adults, although some techniques (e.g., caudal analgesia) are more commonly used in children. There is strong agreement among the panel of consultants and the Task Force members that it is important to recognize that pediatric patients represent a unique population with special features when planning and providing perioperative analgesia.
Recommendations: Anesthesiologists who treat perioperative pain in pediatric patients should be familiar with the special features of this group. Based on that knowledge, pharmacologic and nonpharmacologic strategies for perioperative analgesia appropriate for the age of the child should be offered in a manner that promotes efficacy and safety.
XI. Recognition and Management of Special Features of Geriatric Perioperative Pain Management
Elderly patients are a unique population facing surgery. They may experience physical and mental limitation and may have different attitudes than younger patients with regard to expressing pain and appropriate therapy for it. Altered physiology with aging changes the way analgesic drugs and local anesthetics are distributed and metabolized, frequently necessitating alterations in dosing. There is strong agreement from the panel of consultants and the Task Force members on the importance of recognizing the unique features of geriatric patients in planning and providing perioperative analgesia.
The literature indicates that single and multimodality techniques that have been shown to be effective in younger adult patients are also effective (often with reduced drug dose requirements) in geriatric patients without increasing side effects.
Recommendations: Anesthesiologists who treat perioperative pain in geriatric patients should be familiar with the special features of this group. In particular, dose reduction for drugs that may cause central nervous system depression should be considered.
XII. Recognition of Special Features of Perioperative Pain Management in Ambulatory Surgery Patients
The increasing trend toward ambulatory surgery poses special problems in perioperative pain management. One of the most common reasons for unanticipated hospital admission in this population is inadequate pain control. Analgesic techniques must provide safe, adequate pain relief for patients who quickly leave the supervised hospital environment. Techniques such as EA and intravenous PCA, which require special nursing and monitoring, are not suitable for such patients, but others such as local anesthetic wound infiltration and oral nonsteroidal antiinflammatory drugs may be very effective.
The panel of consultants and the Task Force members strongly agree that the provision of effective analgesia to ambulatory surgery patients is important and beneficial. A limited search of this evolving literature suggests that planning of perioperative analgesia for ambulatory patients including the use of certain procedures (e.g., local anesthetic wound infiltration and certain RA techniques) may improve analgesia without increasing the risk of side effects.
Recommendations: Anesthesiologists who care for ambulatory surgery patients should proactively plan therapeutic strategies appropriate for them, recognizing that they are expected to leave the surgical facility within a few hours after the completion of surgery.
The Task Force thanks those who responded to surveys on acute pain in the perioperative setting, reviewed guideline drafts, contributed oral and written testimony to the Open Forum, and participated in tests of clinical feasibility.
The development of these guidelines included methods recommended in the following publications: (1) Clinical Practice Guidelines--Directions for a New Program, Committee to Advise the Public Health Service on Clinical Practice Guidelines, Division of Health Care Services, Institute of Medicine. Edited by Field MJ, Lohr KN, Washington, D.C., National Academy Press, original document 1990, summary document 1992; and (2) Woolf SH: Manual for Clinical Practice Guideline Development, Washington, D.C., U.S. Department of Health and Human Services. Agency for Health Care Policy and Research, publication number 91-0007, March 1991.
Appendix: Assessment of Scientific Evidence and Consultant Opinion
The scientific assessment was based on the following statements or evidence linkages. These linkages represent directional hypotheses about relationships between perioperative pain management and clinical outcomes.
1. Proactive planning for perioperative pain management improves pain control and reduces adverse outcomes.
2. Education and training of hospital personnel improve pain control and reduce adverse outcomes.
3. Education and participation of patients and families improve pain control and reduce adverse outcomes.
4. Monitoring and documentation activities improve pain control and reduce adverse outcomes.
5. Availability of anesthesiologists providing perioperative pain management improves pain control and reduces adverse outcomes.
6. Standardized institutional policies and procedures for perioperative pain management improve pain control and reduce adverse outcomes.
7. Use of PCA, EA, or RA techniques improves pain control and reduces adverse outcomes.
8. Use of multimodality techniques improves pain control and reduces adverse outcomes.
9. Organizational characteristics related to perioperative pain management improve pain control and reduce adverse outcomes.
10. Pediatric perioperative pain management techniques improve pain control and reduce adverse outcomes.
11. Geriatric perioperative management techniques improve pain control and reduce adverse outcomes.
12. Ambulatory surgery acute pain management techniques improve pain control and reduce adverse outcomes.
Scientific evidence was derived from aggregated research findings, including metaanalyses, and from surveys, open forum presentations, and other consensus-oriented activities. For purposes of literature aggregation, potentially relevant clinical studies were identified via electronic and manual searches of the literature. The search covered a 27-yr period from 1966 through 1993. More than 4,000 articles were identified initially, yielding 465 nonoverlapping articles that addressed the 12 evidence linkages. Studies that could not be analyzed statistically were reviewed and eliminated, yielding 233 articles used in the formal metaanalyses.
A directional result for each study was determined initially by classifying the outcome as (1) supporting a linkage, (2) refuting a linkage, or (3) neutral. The results were averaged to obtain a directional assessment of support for each linkage. The literature relating to linkages 1, 7 (PCA, EA, and RA as separate assessments), 8, 10, and 11 contained enough studies with well defined experimental designs and statistical information for formal metaanalysis. Combined probability tests were applied to continuous data, and an odds-ratio procedure was applied to dichotomous study results.
Two combined probability tests were employed as follows: (1) the Fisher combined test, producing chi-square values based on logarithmic transformations of the reported P values from the independent studies, and (2) the Stouffer combined test, providing representation of the studies by weighting each of the standard normal deviates by the sample size. A procedure based on the Mantel-Haenszel method for combining study results using 2 x 2 tables was used when sufficient outcome frequency information was available. An acceptable significance level was set at P < 0.01 (one-tailed), and effect-size estimates were calculated. Interobserver agreement was established through assessment of interrater reliability testing. Tests for heterogeneity of the independent samples were conducted to ensure consistency among the study results. To control for potential publishing bias, a "fail-safe N" value was calculated for each combined probability test. No search for unpublished studies was conducted, and no reliability tests for locating research results were done.
Significance levels from the weighted Stouffer combined tests for pain reduction were as follows: linkage 1 (P < 0.001, linkage 7 (PCA (P < 0.001), EA (P < 0.001), and RA (P < 0.001)), linkage 8 (P < 0.003), linkage 10 (P < 0.004), and linkage 11 (P < 0.001). Weighted effect size estimates ranged from r = 0.14 to r = 0.35, demonstrating small-to-moderate effect size estimates. Significance levels for all beneficial/adverse outcomes were P > 0.01 (i.e., not significant). Tests for heterogeneity/homogeneity of statistical tests and of effect size estimates were nonsignificant in all cases (P > 0.01), indicating that the various studies provided common estimates of the population effect sizes for the linkages. Agreement among the Task Force members and two methodologists was established by interrater reliability testing. Agreement levels using a Kappa statistic for two-rater agreement pairs were as follows: (1) type of study design, kappa = 0.61-0.65; (2) type of analysis, kappa = 0.65-0.87; (3) evidence linkage assignment, kappa = 0.60-0.74; and (4) literature inclusion for database, kappa = 0.22-0.64. Three-rater chance-corrected agreement values were: (1) design, Sav= 0.62, Var (Sav) = 0.16; (2) analysis, Sav= 0.76, Var (Sav) = 0.15; and (3) linkage, Sav= 0.65, Var (Sav) = 0.12. These values represent moderate to high levels of agreement.
The findings of the literature analyses were supplemented by survey of opinions from a panel of 65 consultant anesthesiologists with expertise in acute pain in the perioperative setting and from the opinions of the Task Force members. Consultants were highly supportive of the linkages (i.e., agreed that they resulted in improvement in pain control, reduced adverse side effects, and were important issues for the guidelines to address). The percentage of consultants supporting each linkage based on these criteria were 1 (86%), 2 (98%), 3 (71%), 4 (78%), 5 (79%), 6 (75%), 7 (74%), 8 (60%), 9 (78%), 10 (86%), and 11 (81%). Linkage 12 was added to the guidelines after completion of the consultant survey.
The feasibility of implementing these guidelines into clinical practice was assessed using a survey of opinions from a panel of 61 consultant anesthesiologists with expertise in acute pain in the perioperative setting. Analysis of the responses indicated that these guidelines can be implemented in a large majority of institutions with minimal additional cost.
Eighty-nine percent of the consultant anesthesiologists indicated that implementation of the guidelines would not result in the need to purchase new equipment, supplies, or pharmaceuticals. Mean estimate of guideline implementation costs for all respondents was $3,705 (range 0 to $100,000). Among the 11% who stated that purchases would be required, the median anticipated cost was $15,000 (mean $32,286, range = $6,000-100,000). Anticipated new equipment consisted of PCA pumps, epidural pumps, and PCA/epidural disposable equipment.
The consultant anesthesiologists were asked to indicate which, if any, of the evidence linkages would change their clinical practices if the guidelines were instituted. The percent of consultants expecting no change associated with each linkage were as follows: proactive planning 82%; education and training 89%; education and participation of patients and families 80%; monitoring and documentation 77%; availability of anesthesiologist 90%; institutional policies and procedures 87%; use of PCA, EA, and RA techniques 90%; use of multimodality techniques 89%; organizational characteristics 90%; pediatric techniques 95%; geriatric techniques 92%; and ambulatory surgery techniques 85%.
Sixty-four percent of the respondents indicated that the guidelines would have no effect on the amount of time spent on a typical case. None reported that the guidelines would reduce the amount of time spent per case. For all respondents, the mean increase in the amount of time spent on a typical case was 3.4 min. Of the 36% of respondents who reported an anticipated increase in time spent on a typical case, the mean was 9.7 min (range 3.0-30.0 min).**
*Clinical Practice Guideline--Acute Pain Management: Operative or Medical Procedures and Trauma, Agency for Health Care Policy and Research. Co-chairs Carr DB, Jacox AK. Washington, D.C., U.S. Department of Health and Human Services, 1992. Available by calling 1-800-358-9295.
**Readers with special interest in the statistical analyses used in establishing these guidelines can receive further information by writing to: L. Brian Ready, M.D., F.R.C.P.(C.), Professor, Department of Anesthesiology, RN-10, Director, UWMC Acute Pain Service, University of Washington School of Medicine, Seattle, Washington 98195.