Acute Pain Management

A Practical Guide

Pamela E. Macintyre, Stephan A. Schug

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000379716
• Edition: 5
• Topic: Medicine
• Subtopic: Anesthesiology & Pain Management

With a focus on practical acute pain management in adults in the hospital setting, this bookprovides health professionals with simple and practical information to help them manage patients with acute pain safely and effectively. • Combines evidence-based information with practical guidelines and protocols • Covers the pharmacology of opioids, local anesthetics, and nonopioid and adjuvant analgesic agents • Discusses management of acute pain in both surgical and nonsurgical acute pain settings including in patients with spinal cord or burns injuries and selected medical illnesses • Includes evidence-based information about management of acute pain in some specific patient groups, including the older patient, opioid-tolerant patients, and those with addiction disorders, pregnant or lactating patients and patients with obstructive sleep apnea or who have renal or hepatic impairment • Considers the role of acute pain management in the context of the current opioid epidemic and identifies possible strategies to minimise the risks.

This resource will be helpful to a variety of professionals in assessing and managing acute pain.

1

Introduction

Over the past years, advances in the management of acute pain have continued, although reports of inadequate pain relief in hospital patients persist. While inadequate staff education and cost restraints may still play a role in this, there has been better recognition of some of the factors that are linked to interindividual variation in reports of pain and response to analgesic medications, as well as a change to looking at how outcomes related to pain relief in broader terms are assessed. There has also been a continued shift in emphasis from the management of the symptom of acute pain to the practice of acute pain medicine, using a more biopsychosocial and multidisciplinary approach to the treatment of patients with a variety of medical, surgical, and psychological comorbidities.

Evidence-based medicine is said to be “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients” (Sackett et al, 1996) and acute pain management practices should also be based on the best possible evidence available. However, if a patient is to get good pain relief and good outcomes from their acute pain treatment, individual variability needs to be considered. Appropriate alterations may need to be made to treatment guidelines, even if they are evidence-based, and to some of the outcomes being sought.

Individualization of treatment does not just apply to the drugs and techniques used for pain relief (see Chapters 4 through 10). There are also some clinical situations or patient groups where pain management may be more complex and additional knowledge is required (see Chapters 12 through 16).

In part, as a result of the opioid “epidemic” and with rising concern that opioids used for the management of acute pain contribute not only to in-hospital adverse events but to risks after discharge including persistent postdischarge opioid use and opioid misuse and diversion, there has been increasing focus on the concept of opioid-free anesthesia and analgesia.

However, the rush to reduce or avoid the need for opioids has led to the introduction of a plethora of adjuvant drugs, often with limited evidence to support their use; there is also, as yet, no evidence to show that opioid-free techniques used in hospitals, including regional analgesia, affect discharge opioid prescribing or prolonged postdischarge opioid use (Kharasch et al, 2020).

While some newer opioids under development may result in effective pain relief with a lower risk of harm (Azzam et al, 2019), current opioids are effective analgesics and are likely to continue to be part of multimodal management strategies for many patients with moderate and severe acute pain for some years yet.

It is how and why they are used that is important. There needs to be a better focus on improved opioid stewardship in the acute pain setting—that is, a universal precautions approach to opioid prescribing and administration, both in hospital and after discharge—and the multiple components of the healthcare system needed to deliver these medicines safely (Levy et al, 2020; Schug, 2020).

1.1 Effectiveness of Acute Pain Management

1.1.1 Assessment of Effectiveness

Since the 1960s, studies of adult hospital patients have consistently highlighted inadequacies in the treatment of acute pain. Changes made to treatment over the last 30 years or more have included the introduction of new techniques for the delivery of analgesic drugs (for example, patient-controlled and epidural analgesia), the development of the concept of multimodal analgesia, the use of new drugs and new ways of using old drugs, and the establishment of acute pain services. Despite this, many publications continue to report that acute pain management in hospital patients is suboptimal.

One the issues that has been increasingly recognized is that while the aim of acute pain management should be to deliver effective pain relief for all patients, assessment of its “effectiveness” must take into account not only a patient’s pain scores but also other aspects that might impact on patient outcome.

As discussed in Chapter 3, there has been an increasing move away from the concept of pain as the “fifth vital sign,” a term first promoted by the American Pain Society in 1995 (Levy et al, 2018), as the main indicator of analgesic effectiveness, and rather than relying on unidimensional patient-reported pain scores alone, an assessment of how pain is affecting the patient’s physical functional should also be made (Joint Commission, 2017; Levy et al, 2018). The focus on pain scores as the sole measure, in an attempt to reduce them to an arbitrarily decided “acceptable” level, led to increased amounts of opioid being given for the management of both acute and chronic pain in hospital and in the community, which inadvertently contributed to an increased risk of harm including opioid-induced ventilatory impairment (OIVI), persistent postdischarge opioid use, and opioid misuse and diversion in the community (Levy et al, 2020).

1.1.2 Variability in Effectiveness

Apart from the drug or technique used to provide pain relief, various other factors can affect the degree of pain or pain relief experienced. In most but not all cases, the differences are of interest only and cannot yet be used as a basis for individualizing patient treatment (Schug et al, 2020).

For example, morphine appears to have greater efficacy in women in both experimental opioid and clinical patient-controlled analgesia opioid (but not opioid analgesia in general) studies, and pain reports are also higher in females than in males with similar disease processes or in response to experimental pain stimuli and after surgery (Schug et al, 2020).

The cultural and ethnic differences in the backgrounds of both healthcare professionals and patients can lead to disparities in assessment, analgesic requirements, and the treatment of pain (Schug et al, 2020).

Genetic differences can affect both the individual’s sensitivity to pain as well as their response (both effect and adverse effects) to opioids (Schug et al, 2020). One well-known example in the acute pain setting is the genetic variability in the enzyme CYP2D6, which is responsible for the metabolism of codeine to morphine and can result in very different plasma levels of morphine for a given codeine dose—see Chapter 4.

Other factors that have been shown to be predictors of higher postoperative pain reports are younger age (pain decreases as age increases), the presence of preoperative pain, and preoperative opioid use. Preoperative anxiety and depression or negative affect and pain catastrophizing may also correlate with higher postoperative opioid requirements and/or pain intensity as well as a higher risk of developing chronic pain after surgery (Chapter 13) and persistent postdischarge opioid use (Chapter 16) (Schug et al, 2020). These factors have also been associated with more widespread reports of pain and persistence of pain after acute musculoskeletal trauma.

1.2 Role of Acute Pain Management in Patient Outcomes

Treatment of acute pain is important not only for the humanitarian reasons of patient comfort and satisfaction but also because it may lead to better patient outcomes—both in the short- and long-term.

1.2.1 Short-Term Outcomes

Use of any analgesic medication or technique should aim to maximize relief of pain while minimizing the risk of adverse effects. OIVI is the most feared adverse effect, and yet discussion about the best measure in the clinical setting continues. Simple clinical monitoring still needs to be improved for all patients given an opioid—see Chapter 3.

Acute pain management using multimodal analgesia is recognized as an important component of a multidisciplinary approach to treatment and rehabilitation aimed at restoration of patient function after surgery and trauma. Development of an ever-increasing number of enhanced recovery after surgery (ERAS) protocols for some types of surgery, where multimodal analgesia combined with early mobilization and aggressive rehabilitation programs, have been shown to improve recovery and reduce duration of hospital stay and the incidence of complications (Schug et al, 2020).

More recently, this work has expanded into both preadmission (prior to elective surgery) and postdischarge patient care with the development of transitional pain services, acute pain service outpatient facilties, and the perioperative surgical home (Katz et al, 2015; Zaccagnino et al, 2017; Stamer et al, 2020). These multidisciplinary teams can provide preoperative plans to improve preoperative pain, function and psychological distress, which can, in turn, lead to less postoperative pain, anxiety, and depression and improved physical function (Levy et al, 2020). The risks of chronic pain and excessive opioid use after hospital discharge can also be reduced.

1.2.2 Longer-Term Outcomes

Outcomes in the longer term are also important. For example, the pain relief technique chosen may impact on the risk of the patient developing chronic postsurgical pain (CPSP)—see Chapter 12. It is also possible that ongoing treatment of acute pain with opioids after discharge from hospital may lead, in some patients, to inadvertent long-term opioid use and the risk of diversion and abuse (Levy et al, 2020)—see Chapter 16.

The ability of analgesic drugs to reduce the risk of cancer recurrence and spread after surgery has also been under discussion for many years. However, good evidence from human studies is lacking, and currently there is no particular anesthetic or analgesic technique that can be recommended for patients undergoing cancer surgery on the basis that it might reduce the risk of recurrence or metastases (Wall et al, 2019).

Other more recently recognized outcomes that may result from longer-term opioid use include effects on immune function and neuroendocrine function, higher risk of postoperative complications, longer hospital stays, and increased healthcare costs—see Chapter 4,.

Key Points

1. Acute pain relief continues to be suboptimal for many patients. The “effectiveness” of any analgesic ...