Prevention/Intervention
Key Points:
- Choices for intervention are varied and frequently involve multiple disciplines.
- With proper education and training of patients prior to a painful experience, the ability to cope and the outcome of pain treatment may be enhanced.
- The use of pharmacological agents is considered to be the mainstay of therapy for acute pain.
- Patient satisfaction can be substantially improved with non-pharmacologic approaches.
Prevention
Patient Education
The ability to influence a patient's pain experience may be approached in multiple ways. Choices for intervention are varied and frequently involve multiple disciplines.
With proper education and training of patients prior to a painful experience, the ability to cope and the outcome of pain treatment may be enhanced.
See Table 3, "Acute Pain Interventions," in the original guideline document for summary of interventions.
Key Patient Education Steps and Messages
- Describe the expected type of pain and how long it will last. (Preparatory Sensory Information - decrease uncertainty and fear of unknown. "Knowledge is power.")
- Individualize the information for the patient.
- Discuss goals of pain management and how these goals help the patient: comfort, quicker recovery, and avoidance of complications.
- Preventing pain is important to manage pain well. "Stay ahead of the pain."
- Many drug and non-drug treatments can be helpful in preventing and managing pain.
- Inform the patient of when and how to contact health care providers about his/her pain.
- Patients, parents of children with pain, and the health care providers will decide as a team which treatments are best to manage the pain.
- Discuss treatment choices and plan, including schedule of medications, which are most appropriate for the patient.
- Addiction to opioids used in the treatment of acute pain is rare. There are differences among physical addiction, tolerance, and psychological dependence.
Medications and interventions are selected based on symptomatology and mechanism of pain. Choosing the profile that is the most responsive to the pain complaint and has the least potential for side effects should be done initially. Visceral, somatic, and neuropathic pain complaints respond most effectively to different treatments. (See the table above). The route of administration often affects patient compliance and dosing requirements.
Pharmacological Therapy
Review Safe Medication Use
Policies and procedures regarding safe medication use should be in place.
The use of pharmacological agents is considered to be the mainstay of therapy for acute pain. There are three broad categories of medications to consider when treating the patient with acute pain: non-opioid analgesics (NSAIDs), opioid analgesics, and coanalgesics. They are used in this manner:
Non-opioid Analgesics (NSAIDs and Acetaminophen)
- Should be considered initially. Often adequate for mild or moderate pain or in the case of ketorolac for moderate to severe pain.
- Have significant opioid dose-sparing properties and in turn reduce opioid-related side effects [A].
- A meta-analysis found a 20% decrease in morphine doses when scheduled acetaminophen was combined with patient-controlled analgesia (PCA) morphine for treatment of pain after major surgery [M].
- Use with caution in patients with coagulopathies or thrombocytopenia and those who are at risk for bleeding.
- Watch for gastrointestinal effects, especially with these risk factors: age greater than 60 years, previous gastrointestinal events and concomitant corticosteroid use.
- Ketorolac, either parenteral or oral, should be used for no more than five days; dose reduction is indicated in the elderly and in those with renal impairment. [Conclusion Grade III: See Conclusion Grading Worksheet A -- Annotation #15 (Ketorolac) in the original guideline document].
Before using NSAIDs, the hematological, gastrointestinal and renal effects should be taken into consideration. All but two NSAIDs, choline magnesium and salicylate, have been shown to inhibit platelet aggregation by inhibiting prostaglandin synthetase. Therefore, care must be used when prescribing NSAIDs in patients with coagulopathies or thrombocytopenia and in those who are at risk for bleeding.
Ketorolac, either parenteral or oral, should be used for no more than five days; dose reduction is indicated in the elderly and in those with renal impairment. [Conclusion Grade III: See Conclusion Grading Worksheet A -- Annotation # 17 (Ketorolac) in the original guideline document]. [B, D]
Opioid Analgesics
- If pain is not adequately controlled with an NSAID or is expected to be moderate to severe, an appropriate opioid should be added to the NSAID.
- In patients with absolute or strong relative contraindications to NSAIDs, an opioid for mild to moderate pain should be considered.
- Morphine is considered to be the standard opioid analgesic.
- Meperidine is not considered a first-line opioid analgesic medication for acute pain syndromes.
- See the original guideline document, Appendix B, "Opioid Analgesics," also "Managing Acute Pain in Chemically Dependent Patients/Recognizing Substance Abuse" in Annotation #17.
Meperidine
Meperidine is an opioid analgesic that has been historically used for the relief of acute pain despite recommendations otherwise.
Meperidine is not considered a first-line opioid analgesic medication for acute pain syndromes. If used, dosing limitations are necessary to prevent central nervous system (CNS) excitatory toxicity from normeperidine accumulation, a metabolite of meperidine. Patients with impaired renal function and elderly individuals are at particularly high risk of CNS toxicity. Patients receiving meperidine should be monitored for symptoms and signs of CNS excitation. [Conclusion Grade II: See Conclusion Grading Worksheet B – Annotation #17 (Meperidine)]
Ketamine
Ketamine is an anesthetic drug with analgesic properties. It is a potent N-methyl-D-aspartate (NMDA) antagonist. The NMDA receptor plays an important role in the development of central sensitization, described as hyperalgesia and the development of the "wind-up" phenomenon. Wind-up describes what is observed during repetitive noxious stimulation resulting in progressively increasing pain intensity. Ketamine may also prevent development of acute tolerance to opioids and opioid induced hyperalgesia. Thus, the ability of a drug to block this receptor is advantageous in acute pain control. However, when administered in high doses, ketamine has significant side effects which limit its usefulness. Hallucinations, paranoia, vivid dreams or delusions, delirium, and floating sensations may be experienced. Limiting the dose and providing a benzodiazepine may help limit these side effects.
The use of ketamine for acute pain control remains controversial. Human studies show mixed results in its ability to provide effective pain relief when used in combination with opioids. Low dose ketamine infusion has been found useful in limiting opioid requirements in patients undergoing major abdominal surgery. Low dose ketamine may be indicated in opioid resistant pain control in cancer patients who have preexisting opioid tolerance. Combining ketamine with morphine in patient-controlled analgesia (PCA) devices has not been proven to be efficacious [A, M].
Patient Controlled Analgesia (PCA)
Patient controlled analgesia (PCA) refers to the method where the patient self-administers analgesics, according to the clinician's order, to control his/her own pain. Most of the time, this refers to a programmable infusion pump that delivers an intravenous opioid to control pain; however, other methods and routes of delivery have been used, such as subcutaneous infusions.
PCA administration can consist of a patient-controlled demand (bolus) dose given at some frequency and/or some continuous rate of opioid infusion (usually expressed as mg/hour) along with a lockout interval. Lockout interval refers to the time between boluses where the pump will not allow any more bolus doses to be administered.
Patient-controlled analgesia is more than just intravenous (IV) administration of opioids; however, this guideline will only delineate IV PCA because its use has more potential for dangerous side effects [R].
- The key to safe use of PCA is close monitoring by the professional. Monitoring parameters should be established to meet individual institutional needs.
- The first 24 hours after surgery represent a high-risk period for a respiratory event, and sedation is highest within the first 12 hours postoperatively [C].
- The relative safety of continuous infusion is increased if a patient's opioid requirements are already known and the rate of infusion is based on those requirements.
- Continuous infusion should be used with caution in patients with sleep apnea and those who are morbidly obese [R].
- Patients with a history of opioid consumption (whether legally or illegally obtained) may require higher than average PCA dosages.
- PCA is an effective method of pain relief in the elderly.
- If stable pain rating, as determined collaboratively by clinician and patient, monitoring may be less frequent.
- Naloxone should be readily available.
- Determining dose for equalanalgesic conversions should be based on the calculation of mg used/24 hours.
The primary advantage of PCA therapy is the patient convenience since the patient controls when a dose of analgesic is given; the patient is not dependent upon a nurse to get a dose of analgesic. If appropriate doses of opioids are prescribed, the patient should not be at risk of respiratory depression because with repeated boluses, the patient falls asleep, avoiding additional doses that might cause respiratory depression. The drawbacks of PCA include the increased expense of administering the medication because the pump and equipment are relatively expensive.
Safe dosing of opioids for PCA is very patient-dependent. Generally, lower doses are used for the elderly and opioid-naive patients, while equalanalgesic calculations should guide the prescriber for chronic opioid patients who now have acute pain. Opioid doses may be titrated based on analgesia and side effects.
When intravenous access is not possible, PCA may be administered via the subcutaneous route.
Inappropriate candidates for PCA therapy include those patients who are physically or cognitively unable to self-administer demand/breakthrough medication. In the treatment of acute pain, each institution should have guidelines delineating who may administer the demand dose, in order to safely provide analgesia.
Breakthrough Pain
Expert consensus has suggested the following guide for breakthrough dosages: 10 to 20 percent of the total daily long-acting oral opioid dose. Since the duration of action of many oral short-acting opioids is around four hours, the frequency may be every four hours as needed for breakthrough pain [R].
Coanalgesics
Coanalgesics are used to complement NSAIDs and opioids and may be used alone for the treatment of acute pain, especially neuropathic pain.
Some have been shown to enhance the effect of a particular analgesic, such as caffeine when given with aspirin-like drugs; others have analgesic properties themselves, e.g., tricyclic antidepressants and hydroxyzine.
The use of adjuvant therapies and medications is frequently helpful in reducing the total drug dose of opioids and NSAIDs, and speeding recovery. These medications may treat acute pain alone but are often used in combination with other analgesic therapies.
Refer to the original guideline document for information on tricyclic antidepressants, antiepileptic drugs, local anesthetics, and management of acute pain in chemically dependent patients.
Specialty Consult (if indicated)
General surgical, orthopedic, anesthesiological or other consultation may be deemed necessary.
Intervention/Surgical Procedures
Procedures are used for both diagnostic and therapeutic effects and should be performed by experienced providers.
Preemptive Analgesia
Clinical studies have indicated that painful stimuli may produce changes in the spinal cord that in turn influence the response to further stimuli. The hypothesis of preemptive analgesia states that, by preventing the sensitization of the central nervous system which would normally amplify subsequent nociceptive input, one may reduce the severity of postoperative pain. The neuroplastic response may be prevented by appropriate administration of analgesics before the stimulus in order to block painful nerve transmission. Thus, to be considered preemptive, the intervention must be given before the actual insult (e.g., surgical incision). A nerve conduction block is typically required, either by infiltration of local anesthetics near the site of expected injury, or by neuraxis blockade in the epidural or intrathecal spaces, also with local anesthetic. The use of neuraxial opioids may also play a role. Application of local anesthetics or opioids near the spinal cord is usually performed by an anesthesiologist. The N-methyl-D-aspartate (NMDA) receptor is also thought to play a key role in the development of central nervous system sensitization. Thus, the use of an NMDA antagonist may be helpful. However, results of studies evaluating the effects of preemptive analgesia have been mixed and have not shown definitive benefits [A, M].
Non-Pharmacologic Approaches
There is growing interest among patients and providers in non-pharmacologic complementary therapies for acute pain. Little conclusive advice can be drawn from studies available to date for several reasons. First, there is a broad range of therapeutic modalities, including:
- Education
- Immobilization (e.g., bracing, bed rest)
- Physical (e.g., massage [A], heat, cold, transcutaneous electrical nerve stimulation [TENS])
- Cognitive/Behavioral [R] (e.g., biofeedback, relaxation [R])
- Exercise (e.g., back school, graded exercise) [R])
Likewise, studies cover diverse conditions, such as headaches, low back pain, blood draws/injections [A]; perioperative pain, neck pain, and tooth extraction [A]. Even when similar conditions and treatments are compared, the method of delivering specific therapies often isn't uniform among providers. Furthermore, the majority of studies focus on chronic pain, not acute. Finally, outcome measures amongst studies tend to be heterogenous or lack statistical significance. Several studies have shown a small positive effect of non-pharmacologic treatments, but it remained unclear if the effect was adequate to justify the cost [A].
Non-pharmacologic treatment of low back pain appears to be the best studied. A recent extensive review [M] found that for acute low back pain, only heat application bore strong evidence for efficacy [A]. Conflicting evidence has been noted with transcutaneous electrical nerve stimulation and ultrasound and numerous other treatments. Nonetheless, even when a significant decrease in pain isn't shown, patient satisfaction can be substantially improved with non-pharmacologic approaches [A].
Clinical Pearls
Pediatric
- Circumcisions: The March 1999 Task Force Report from the American Academy of Pediatrics states, "If a decision for circumcision is made, procedural analgesia should be provided. Dorsal Penile Nerve Block (DPNB), EMLA (Eutectic Mixture of Local Anesthetics), topical lidocaine, and ringblock have all been shown to be efficacious and safe but none completely eliminate the pain of circumcision" [A, R].
- Percutaneous procedures: Eutectic mixture of local anesthetics (EMLA): Mixture of lidocaine and prilocaine applied under occlusive dressing (onset of action of 60-90 minutes) has been shown to be useful in venipuncture, intravenous access, circumcision, and meatotomy [A, M]. There have been concerns about methemoglobinemia which thus limits its use in neonates or infants. Recent studies in small populations demonstrate little toxicity.
- Intramuscular injections should be avoided if possible; most surveys indicate children would rather experience pain [A].
- Acute musculoskeletal pain: A single dose of ibuprofen was shown to provide better analgesia than codeine or acetaminophen. Despite its superiority, according to the authors, "ibuprofen alone is not adequate for relieving pain in all children with musculoskeletal injuries" [A].
Adults
- Acute ureteral colic: Parenteral NSAIDs are more effective than meperidine [M, A].
- "As needed" basis: For optimal treatment of acute pain, avoid the use of intramuscular injections ordered on an "as needed" basis [A]. Acute pain medications should initially be titrated to effect and then given on a scheduled basis.
- Suturing non-end-artery sites: Use TAC (tetracaine, adrenaline, and cocaine solution), or LET (lidocaine, epinephrine, and tetracaine solution) [R, A]. See supporting references in the original guideline document for solution concentrations.
- Head injury and stroke: Avoid strong opioids to allow adequate patient assessment. Strong opioids may also decrease respiration rate, which may adversely affect (increase) intracranial pressure [D]
.
- Medication interaction: Oxycodone, hydrocodone, codeine and tramadol may not be effective analgesics when given with other agents that strongly inhibit the Cytochrome P4502D6 liver enzymes [A, R]. Common agents with this characteristic include the selective serotonin reuptake inhibitors [R].
- Propoxyphene is no more effective than acetaminophen in acute pain [C].
- "Road rash": NSAIDs (any route) or local anesthetic can be used.