Pain continues to be prevalent among patients undergoing major surgical procedures. Data from 1973 to 1999 reported incidence rates of moderate to severe pain and severe pain of 29.7% and 10.9%, respectively.⁴ When only intramuscular (IM) analgesia was used, the incidence of pain was even higher: 67.2% and 29.1% for moderate to severe pain and severe pain, respectively. Moving forward to 2006, a cross-sectional study in a large Canadian teaching hospital showed that the incidences were essentially unchanged, at 31.5% and 11.4% for the same two categories.⁵ Postoperative pain levels vary for different surgical procedures, even among the surgical options for hip fracture repair. This finding should be taken into account in pain management.⁶

No evidence indicates that elderly patients experience less pain than younger patients.^7,⁸ In patients undergoing hip replacement, no correlation was found between age and pain score.⁹ However, difficulties in assessment and concern about risk may lead to undertreatment of pain, especially in cognitively impaired elderly patients. In one study of hip fractures, patients with advanced dementia (median age, 88 years) received only one third the amount of opioid compared with cognitively intact patients (median age, 82 years), although 40% of the cognitively intact group already reported severe to very severe pain even with the higher opioid doses that they were given. Furthermore, only 24% of the noncommunicative patients received a standing order for analgesia.¹⁰ Thus, elderly patients are at high risk for undertreatment of pain associated with hip fractures.

After Hospital Discharge

Patients often report poor pain control following discharge from the hospital. Although it is known that a quick count of analgesics used in the 24 hours before discharge may provide an accurate indication of the analgesic requirement for the next few days, the potency, dose, and duration of analgesic prescribed often do not take into account differences in individual requirements. Moreover, after leaving the hospital, patients who had hip fractures were found to receive significantly less medication in the first 24 hours in the nursing home compared with the last 24 hours of hospitalization. More than one third of the patients received no opioid, and 18.3% received no analgesic of any kind.¹¹ Communication about medical care should include treatment of pain and is essential for continuity of care as patients are transferred across settings.

Assessment of Pain

Pain assessment is the first step in optimally managing pain. Self-reporting is considered the gold standard of pain measurement. Legal health and safety codes are being updated to include pain in all health personnel assessment processes. California and other health facilities licensed shall, as a condition of licensure, include pain to be assessed at the same time as other conventional vital signs. The pain assessment is to be performed in a consistent manner that is appropriate to the patient and documented in the patient’s chart with other vital signs.^11a This concept of the “fifth vital sign” will help to establish a new standard of pain assessment and documentation based on self-reporting in all patients. Pain assessment tools include multidimensional tools, unidimensional tools (intensity of pain), and, for patients who are unable to use self-reporting scales, observational tools.

Multidimensional Tools

Pain is a multidimensional experience, and multidimensional tools such as the McGill questionnaire have been used to assess the sensory, affective, evaluative, temporal, and miscellaneous qualities of pain.^11b The short-form McGill questionnaire may also be used in acute pain assessment.

Unidimensional Tools

Unidimensional self-reporting scales are most commonly used to measure pain intensity or degree of pain relief. These scales can be verbal description scales (VDSs), numeric rating scales (NRSs), visual analog scales (VASs) and picture scales:

• A verbal rating scale (VRS) measures the intensity of pain or response to treatment. For example, the patient is asked to choose from the list “none, mild, moderate, severe, excruciating” to describe the intensity of his or her pain. The scale is simple, easy to understand, suitable for elderly patients and older children. The disadvantages are that it is a noncontinuous scale, the change in pain intensity between each word may not be the same, the patient is asked to select a word that may not describe his or her own pain experience, and the scale is subjected to bias.

• An NRS, using the numbers from 0 to 10 (0 being no pain and 10 being the worst possible pain), is also simple and correlates with VASs. An NRS has been found to be the preferred pain intensity scale. However, the scale may not necessarily be linear (e.g., an increase in severity of pain from 7 to 8 is not the same as a change from 1 to 2) (Fig. 5-1).

• The VAS uses a 10-cm straight line, with one ending indicating “no pain” and the other end “the worst possible pain.” The patient is asked to mark on the line to indicate the intensity of the pain. The VAS can also be modified to measure the degree of pain relief. This scale may be more difficult to understand for elderly patients, cognitively impaired patients, and patients with an impaired level of consciousness.

• Picture scales and pain drawings that show a series of faces to indicate increasing levels of pain can be used by children, as well as by patients with language difficulties (Fig. 5-2).

Figure 5-1 Numeric pain rating scale.

Figure 5-2 Faces pain rating scale.

Observational (Behavioral) Tools in Elderly Patients with Cognitive Impairment

Elderly people find it more difficult to use self-report scales correctly than do younger adults.¹² In some elderly and cognitively impaired patients, self-reporting may not be reliable. Changes in vital signs and autonomic responses as indicators of pain may be helpful in acute pain assessment, but these signs are nonspecific and difficult to discriminate from other states of distress. Observational (behavioral) tools have been developed to measure pain in cognitively impaired patients. These tools are staff administered and commonly estimate pain according to a checklist consisting of vocalizations, facial expressions, and body language that suggest pain (Table 5-1). Some tools were reported to have better reliability and validity (DS-DAT, PAINAD, PACSLAC, DOLOPLUS2, and ECPA),^13,¹⁴ but no single tool is the most appropriate for use in elderly patients with cognitive impairment. Most observational tools need further vigorous development and testing.

Table 5-1 An Example of an Observational Scale: Pain Assessment in Advanced Dementia (PAINAD) Scale

Recommendations for pain assessment in elderly patients are as follows ¹⁵:

• An attempt should be made to use unidimensional measurement tools.

• A validated observational tool designed to assess pain among older adults with cognitive impairment should be used. Clinicians using servational pain assessment tools should exercise great caution because observational tools may fail to identify pain or a high score may reflect behaviors other than pain.

• Patients’ histories, results of physical examinations, and caregiver reports should be given careful consideration.

• The approach to pain assessment should be individualized for each patient: collection of regular baseline scores, observation of deviations from such baseline scores, rating of pain under consistent circumstances, and observations about whether interventions or treatments reduce pain behavior.

• Caregivers should consider that pain behaviors are generally more likely to be elicited during movement than at rest.

Pharmacotherapy: Drugs Commonly Used in Multimodal Analgesia

Acetaminophen

Acetaminophen is thought to be a weak indirect inhibitor of cyclooxygenase (COX). It is an antipyretic and weak analgesic. It has few side effects unless the recommended dose limit (4 g/day in adults ¹⁶) is exceeded. The United States Pharmacopoeia Dispensing Information (USPDI) recommends 2.6 g/day for long-term use (>10 days).¹⁷ There is no consistent age-related effect on the clearance of acetaminophen. Hence, one may not need to reduce the dose for elderly patients.¹⁸ However, in patients with preexisting liver disease or a history of heavy alcohol intake, daily doses should be reduced by 50% or 75%.¹⁸ Patients should be educated that many over-the-counter medications contain acetaminophen. Overdose may lead to fatal liver failure. In one report, acetaminophen was found to be the most common cause of acute liver failure, and it accounted for 39% of cases.¹⁹

Nonsteroidal Anti-inflammatory Drugs

NSAIDs have analgesic, anti-inflammatory, and antipyretic properties. These drugs can be used alone for mild to moderate pain. When used in combination with opioids, NSAIDs improve pain control and reduce opioid requirements by up to 30%.^20,²¹ NSAIDs also decrease postoperative nausea and vomiting (≤30%) and sedation (≤29%).²²

Duration of Action and Potency

Ibuprofen is a short-acting and low-potency NSAID used in a single dose of 200 to 800 mg up to a maximum of 3.2 g (United States) or 2.4 g (Europe) in rheumatoid arthritis. Short-acting, high-potency NSAIDs include diclofenac, indomethacin, and ketoprofen. Diclofenac is also COX-2 selective (see later). Naproxen has intermediate potency and an intermediate half-life. Meloxicam, piroxicam, and tenoxicam have high potency and slow elimination and are mostly used for longer-term inflammatory pain.

Well-known side effects of NSAIDs include gastrointestinal (GI) bleeding, bronchospasm in asthmatic patients, impaired hemostasis (except COX-2–selective inhibitors), renal toxicities, transient elevation of liver enzymes, and CNS effects that include dizziness, drowsiness, and alterations in mood and cognition that may be significant in elderly patients. Concerns about tissue and bone healing have influenced the use of NSAIDs in some orthopaedic patients, and the increased cardiovascular risk further limits the use of NSAIDs in patients at risk.

Cardiovascular Risk

NSAIDs differ in their selectivity in inhibiting the two isoforms of COX: COX-1 and COX-2. The COX-2 selectivities are as follows: rofecoxib > valdecoxib > parecoxib > celecoxib = diclofenac >> indomethacin, ibuprofen. COX-2–selective inhibitors have reduced GI toxicity by sparing COX-1 in the GI mucosa. Selective COX-2 inhibition also suppresses endothelial cell synthesis of prostacyclin, which has antiplatelet and vasodilatory effects. This effect shifts the prothrombotic-antithrombotic balance on endothelial surfaces toward thrombosis.

In the VIGOR trial (Vioxx Gastrointestinal Outcomes Research), the relative risk of developing thrombotic cardiovascular event (myocardial infarction, unstable angina, cardiac thrombus, resuscitated cardiac arrest, sudden or unexplained death, ischemic stroke, and transient ischemic attack) with rofecoxib treatment compared with naproxen was 2.38. Further reports showing the cardiovascular risks of COX-2–selective inhibitors and other NSAIDs changed the recommendations about the use of NSAIDs in clinical practice.²³^–²⁶

Published data showed an increased risk of cardiovascular event for COX-2–selective inhibitors (relative risk, 1.42) and some traditional NSAIDs. Individual drugs implicated included rofecoxib, diclofenac, meloxicam, indomethacin, high-dose ibuprofen (800 mg three times daily) but not lower-dose ibuprofen, piroxicam, naproxen, and celecoxib at 200 mg/day or less. In patients with previous myocardial infarction, selective COX-2 inhibitors in all dosages and nonselective NSAIDs in high dosages increased mortality rates.²⁷^–³⁰ One review concluded that the overall risk of myocardial infarction with NSAIDs and COX-2–specific drugs was small, but rofecoxib had the highest risk.³⁰ A Scientific Statement from American Heart Association recommended a stepped-care approach (Fig. 5-3) to management of musculoskeletal pain in patients with known cardiovascular disease or who are at risk for ischemic heart disease.³¹

Figure 5-3 Management of musculoskeletal pain in patients with known cardiovascular disease or who are at risk for ischemic heart disease. COX, cyclooxygenase; NSAID, nonsteroidal anti-inflammatory drug.

(Adapted from Antman E, Bennett J, Daugherty A, et al. Use of nonsteroidal antiinflammatory drugs: an update for clinicians: a scientific statement from the American Heart Association. Circulation 2007;115;1634-42.)

Bone Healing

COX activity is involved in the healing of skeletal tissues. Indomethacin has been used to prevent heterotopic ossification after hip replacement. In some animal models, NSAIDs correlated with various degrees of bone healing impairment. There were also clinical reports that high doses or long-term postoperative use of NSAIDS increased the risk of developing fracture nonunion. However, a review of the literature showed contradictory results about the effect of NSAIDs on bone healing and a lack of well-conducted randomized clinical data.^32,³³ More research is required on this topic.

Gastrointestinal Complications

The incidence of hospitalization for NSAID-related upper GI bleeding is 1% to 2% per year, and this complication has a 5% to 10% mortality rate.³⁴Helicobacter pylori infection and NSAID use act synergistically and are the two main causes of peptic ulcer.³⁵ Factors in NSAID-related GI bleeding are age older than 60 years, a prior GI event, high NSAID dosage (>2 × normal), and concurrent use of corticosteroids and anticoagulants.³⁶ Dyspepsia occurs in 10% to 20% of patients taking NSAIDs but is not predictive of ulcer development. In descending order, the highest-risk NSAID-related GI complications are caused by indomethacin, diclofenac, piroxicam, tenoxicam, ibuprofen, and meloxicam. Short-acting NSAIDs are less toxic than long-acting NSAIDs.³⁷ The COX-2–selective inhibitor celecoxib is associated with an ulcer incidence similar to that seen with placebo.³⁵ Most patients remain asymptomatic until they experience a life-threatening GI hemorrhage.

Taking NSAIDs with food can reduce GI side effects. The risk of NSAID-related ulcer is reduced by 40% with the use of misoprostol, a prostaglandin E analogue with side effects of nausea, diarrhea, and abdominal pain. Proton pump inhibitors (PPIs) have slightly lower efficacy but are better tolerated. Histamine (H₂)-receptor antagonist therapy is inadequate.³⁸

Optimization in Pain Control

Recommendations for the use of NSAIDs came from the Scientific Statement of American Heart Association,³¹ from reviewers,³⁵ and from the American Gastroenterological Association (AGA). Recommendations from AGA Consensus Development Conference on the Use of NSAIDs include the following³⁸:

• Review treatment indications and risk factors.

• Prescribe lower-risk agents.

• For patients whose risk of GI bleeding is greater than their risk of cardiovascular events, consider NSAIDs with a lower GI risk (e.g., ibuprofen, etodolac, and diclofenac, and coxib agents).

• For patients whose risk of cardiovascular events is higher than their risk of GI bleeding, COX-2 inhibitors should be avoided.

• In patients with known cardiovascular disease or at high cardiovascular risk, low-dose aspirin (ASA) should be prescribed, although the benefit of the combined use of aspirin and NSAIDs is unclear.

• Limit duration and dosage.

• Ask about and avoid combination NSAID therapy.

• Treat known H. pylori infection, but routine H. pylori testing should not be pursued in average-risk patients starting NSAID therapy.

• Monitor all patients taking NSAIDs for cardiovascular side effects.