In 2004, a Canadian survey showed that the percentage of academic hospitals with an APS increased from 53% in 1993 to 92% in 2004.²⁶ However, an APS with anesthesiologists as sole pain management providers decreased from 36% to 22% in the same time span because of growing clinical demands and a reduced number of anesthesiologists. Only 44% of centers had a designated group of APS physicians, whereas nursing representation was 55%. An ongoing prospective data collection system was present in 29% of the hospitals surveyed. No information was obtained about the management of acute pain in patients who were not followed by an APS, which represented the majority of postoperative patients.²⁶ Furthermore, recent evidence indicates that some APSs provide only a limited service due to financial or logistical problems. These findings suggest that there is a compelling need to develop APS standards with well-defined criteria for evaluating performance and comparing with national benchmarks.²⁷

       STRUCTURE & FUNCTION OF AN ACUTE PAIN SERVICE

The original organizational model for managing postoperative pain was largely catalyzed by an APS developed in the United States²¹ and gradually introduced in the United Kingdom during the 1990s after the landmark report “Pain After Surgery.”⁷ However, implementation of APSs in hospitals since 1990 has been piecemeal and haphazard, with reports providing evidence of significant variation within and among hospitals in the structure and function of the service.²⁷

        Most major hospitals in the United States have an anesthesiology-based APS. The acute pain management team usually consists of staff and resident anesthesiologists, specially trained nurses, pharmacists, and physical therapists. Secretarial and billing personnel are also a part of a United States-style APS. Members of the pain management team regularly visit patients under the care of an APS. The anesthesiologist-based APS organization model usually provides a “high-tech” pain management service to patients receiving epidural analgesia or intravenous patient controlled analgesia (IVPCA). However, the costs of the United States- style APS are high and are being increasingly questioned by health care payers. In many institutions, surgeons have assumed management of IVPCA.

        The need for new APS models that provide effective pain relief for all surgical patients is clear. As discussed later, the nurse-based, anesthesiologist-supervised APS model is an alternative to the conventional physician-based APS model. The United Kingdom Joint Colleges of Surgery and Anesthesia Working Party report⁷ recommended that a multidisciphnary team including specialist nursing staff should run the APS. They further recommended that the APS should assume day- to-day responsibility for the management of postoperative pain, in-service training for nursing and medical staff, and research and auditing. Similar recommendations have been made by national expert committees in Australia,⁶ the United States,^8–10 Germany,⁹ Sweden,¹¹ and in an updated form by the American Society of Anesthesiologists (ASA) Task Force.¹² In the United Kingdom, two national surveys^14–15 were conducted to determine the extent to which the recommendations of the Working Party report had been implemented. Unfortunately, there appeared to be a large degree of variation in what was thought to constitute an APS, and some hospitals had only some of the elements recommended by the Working Party report.^18–20

        An ideal APS organization should provide optimal pain management for every surgical patient, including children and those undergoing outpatient surgical procedures. The Joint Commission for Accreditation of Healthcare Organizations (JCAHO), an independent not-for-profit organization that sets health care standards in the United States, recognizes the need for optimal pain management. JCAHO requires that hospitals assess, treat, and document pain, assures the competence of staff in pain assessment and management, and educate patients and their families about effective pain management. Hospitals must also consider ambulatory surgery patients’ needs for information and provide guidelines for pain management after discharge from the hospital.²⁸

        One of the most important activities of an APS is to provide an ongoing review of institutional policies and practices regarding pain control and the mechanisms to deal with problems as they arise. The members of the APS should meet regularly to provide feedback and discuss opportunities for improvement. Such meetings are important for assessing the efficiency of the APS, highlighting practical problems, and finding solutions for inadequately functioning aspects of the APS.²⁹

        Although each institution may have different requirements for their own APS, modifications of published models may be necessary to accommodate local conditions. The main components of an APS should include the following:

        DOES AN ACUTE PAIN SERVICE IMPROVE OUTCOME?

It is believed that the introduction of an APS has led to an increase in the appropriate use of specialized analgesic techniques, such as IVPCA opioid, epidural, and perineural analgesia. The implementation of these techniques may represent a true advance in improving analgesia and patient well-being and in reducing postoperative morbidity.^12–13 An APS can reduce analgesic gaps that occur during the transition from IVPCA or epidural analgesia to oral analgesic therapy. Although evaluating the safety of analgesic techniques is an important objective of an APS, its role in preventing and reducing adverse events has not been well established. Wheatley and colleagues³⁰ reported a decrease from 1.3% to 0.4% in the incidence of lower respiratory tract infection after the introduction of an APS. Tsui and coworkers³¹ investigated the benefits of an APS program in patients undergoing esophagectomy. The patients were cared for either by an APS (n = 299) or received conventional analgesic therapy in a non-APS setting (n = 279). In the APS group, patients received postoperative epidural or systemic opioid infusion, and the non-APS group received intermittent intramuscular injections of morphine. The APS group reported a significantly lower incidence of pulmonary and cardiac complications and a shorter hospital stay.³¹ Other studies,^13,32,33 have not substantiated these findings.

        Werner and associates¹³ evaluated the effects of an APS on postoperative outcome in 44 audits and four clinical trials, which included 84,097 patients. Implementation of an APS was associated with a significant decrease in pain intensity. Additionally, the introduction of an APS was possibly associated with less postoperative nausea and vomiting and a decreased incidence of urinary retention. However, clear conclusions about the side effects of analgesic modalities, patient satisfaction, or postoperative morbidity could not be drawn due to a large variability in the studies regarding APS function and services provided.¹³ McDonnell and colleagues³⁴ found that the implementation of an APS was associated with initiatives that are hallmarks of good postoperative pain management, but did not explore the effect of an APS on postoperative outcomes. Hospital administrators are more likely to invest in an APS if implementation of such a service results in measurable improvements in patient outcomes at an affordable cost.

        COST-EFFECTIVENESS OF AN ACUTE PAIN SERVICE

Cost-benefit analyses are necessary to justify the need for an APS, but no such studies are available. Cost analyses of acute pain management are impeded by the lack of a well-defined baseline and outcome assessment. There is no valid method of assigning financial costs to differing levels of analgesia, and the effect of various analgesic techniques on economic outcomes has not been adequately examined.¹³

        Cost-effectiveness analyses of postoperative pain management must consider not only the direct costs associated with analgesic drugs; devices; nursing and physician time; and duration of stay in the postanesthesia care unit, intensive care unit, or surgical ward, as well as postoperative morbidity; but also the indirect costs of improved analgesia and patient satisfaction.¹³

        Brodner and coworkers³⁵ showed that the introduction of a multimodal program with improved pain relief, stress reduction, and early tracheal extubation decreased the number of patients who required a stay in an intensive care unit in the immediate postoperative period after major surgery. The hospital realized cost savings because of faster discharge from the high-dependency areas.³⁵ In an effort to reduce APS-related costs, several authors have advocated a low- cost, nurse-based, anesthesiologist-supervised model^5,36–38 as an alternative to the more expensive physician-based multidisciplinary APS.^38–41 Currently, there is no evidence that a physician-based multidisciplinary APS is superior to a specialist nurse-based, anesthesiologist-supervised APS. Although cost-benefit studies are difficult to perform, there is a compelling need for such studies.

Figure 78-1. Management of postoperative (acute) pain: Choice of techniques and drugs based on the severity and timing of surgery. Acetaminophen is given to all patients irrespective of pain intensity or type of surgery.

        STRATEGIES FOR IMPLEMENTING AN ACUTE PAIN SERVICE

It is becoming increasingly clear that physicians must develop simple and less-expensive APS models for improving the quality of postoperative analgesia for every surgical patient (including day surgery patients) in a cost-effective way. At Örebro University Hospital in Orebro, Sweden, a pain specialist nurse-based, anesthesiologist-supervised model has been successfully implemented.⁵ The first step to initiating a pain management program is organizing an interdisciplinary team of motivated individuals who represent diverse professional skills and approaches to patient care.

        The anesthesiologist is responsible for both anesthetic care and postoperative pain management and selects the appropriate analgesic modality based on the departmental policy of using the “acute pain analgesic ladder” (Figure 78-1). A recent ASA practice guidelines publication¹² recommends similar therapeutic strategy. The publication suggests that, unless contraindicated, all patients should receive an around-the-clock regimen of nonsteroidal antiinflammatory drugs, cyclooxygenase inhibitors, or acetaminophen. In addition, anesthesiologists should consider performing regional blockade with local anesthetics. The choice of medication, dose, route, and duration of therapy however should be individualized.¹² During regular working hours, an anesthesiologist should be available for consultation and emergencies, and after hours, the anesthesiologist on-call should assume the same function.

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Regional Anesthesia in the Patient with Preexisting Neurologic Disease. Preemptive Analgesia, Regional Anesthesia, & the Prevention of Chronic Postoperative Pain. Newer Amide Anesthetics & Sustained-Release Local Anesthetics1. Diagnosis & Management of Intraspinal, Epidural, & Peripheral Nerve Hematoma. Histology of Peripheral Nerves. Supraclavicular Brachial Plexus Block.