Continuing Education Activity

Postoperative pain is experienced by the vast majority of patients who undergo surgical procedures. Control of postoperative pain plays an essential role in facilitating a patient’s recovery to normal function and reduces the incidence of adverse physiologic and psychological effects associated with acute, uncontrolled pain. Postoperative pain control may be achieved by a variety of mechanisms, including (but not limited to) the use of pharmacological agents and interventional techniques. This activity outlines the indications, evaluation, treatment, and implications of pain control in the postoperative patient.

Objectives:

• Identify the indications and contraindications for postoperative pain control.
• Describe the equipment, personnel, preparation, and technique needed for postoperative pain control.
• Review and evaluate the potential complications and clinical significance of postoperative pain control.
• Outline interprofessional team strategies for improving care coordination and communication to advance postoperative pain control and improve outcomes in patients following surgery.

Introduction

The goal of postoperative pain control is to reduce the negative consequences associated with acute postsurgical pain and help the patient make a smooth transition back to normal function. Traditionally, opioid analgesic therapy has served as the mainstay of treatment for acute postoperative pain. However, the recent rise in morbidity and mortality associated with opioid misuse has led to increasing demands for more investigative efforts into developing pain treatment strategies that place more emphasis on using a multimodal approach.[1] These efforts have proved to be challenging, as the subjective nature of pain perception further complicates the ability to achieve satisfactory pain control. Furthermore, specific patient comorbidities and social factors may predispose patients to have increased pain perception.[2] 

Approximately 75 percent of patients who undergo surgery experience acute postoperative pain, which is often medium-high in severity.[3] Less than half of patients undergoing surgery report adequate postoperative pain relief.[2] This percentage presents a significant problem as inadequate postoperative pain control may lead to adverse physiologic effects among patients in the immediate postoperative period and places them at increased risk of developing chronic pain associated with the procedure.[4] Severe persistent postoperative pain affects 2 to 10 percent of adults.[5]

Among the issues that make pain control difficult is a lack of pain level surveillance protocols or intervention guidelines that would help provide more efficient means of adjusting therapy for providing better pain relief.[5]

Anatomy and Physiology

Afferent neural pathways mediate the sensation of pain. [6] Acute post-surgical pain can categorize as nociceptive, inflammatory, or neuropathic. Nociceptive pain gets mediated by activated unmyelinated C-fibers, thinly myelinated A-delta-fibers, and myelinated A-beta-fibers and usually occurs in response to noxious stimuli such as direct intraoperative tissue injury (ex, making a skin incision). Inflammatory pain occurs when nociceptive fibers become sensitized in response to the release of inflammatory mediators such as cytokines. The clinical manifestation of inflammatory pain may be composed of the four classic signs of inflammation (pain, heat, erythema, and swelling). Inflammatory pain may last hours to days in duration and is generally reversible. Neuropathic pain results from injury to neuronal structures (ex. peripheral nerves), whereby pain occurs due to increased axonal sensitivity to stimuli. Neuropathic pain will present in the immediate post-operative period and may persist as chronic postoperative pain.[7]

Postoperative pain can additionally characterize as somatic or visceral. The somatic division of pain is composed of a rich input of nociceptive myelinated, rapidly conducting A-beta-fibers found in cutaneous and deep tissue, which contribute to a more localized, sharp quality.[3][7] The visceral division of pain is composed of a network of unmyelinated C-fibers and thinly myelinated A-delta-fibers that span across multiple viscera and converge together before entering the spinal cord. Also, visceral afferent fibers run close to autonomic ganglia before their entrance into the dorsal root of the spinal cord. These characteristic features of visceral nociceptive fibers are what contribute to a more diffuse, poorly localized pattern of pain that may be accompanied by autonomic reactions such as a change in heart rate or blood pressure.[7]

Therapeutic interventions developed for pain management aim to target the afferent pain pathway by various mechanisms. For example, by antagonizing pain receptor activity or by blocking the production of pro-inflammatory mediators.[6]

Indications

Postoperative pain management tailored individually to a patient’s comorbidities and social factors are associated with reduced postoperative opioid consumption, reduces the length of hospital admission after surgery, decreases preoperative anxiety, and results in fewer sedative medication requests.[2]

Contraindications

Pharmacological agents used in mediating postoperative pain control are contraindicated when the patient has a history of allergic reactions associated with their use.

Contraindications to NSAIDs include patients who undergo coronary artery bypass graft surgery due to an increased risk of cardiovascular events.[2]

Equipment

Equipment used in techniques that involve the delivery of interventional postoperative pain relief:

• Peripheral IV access
• Sterile skin preparation
• Sterile field
• Vital sign monitoring: Pulse oximetry, telemetry, noninvasive blood pressure monitoring
• Resuscitation equipment: Oxygen supply, airway supplies, suction, resuscitative medications, and defibrillator
• Ultrasound machine
• Anesthetic medication
• Hollow needles: Needle gauge, shape, and length vary according to the type of anesthesia performed: e.g., beveled needles, spinal needles
• Catheter assembly
• Peripheral nerve stimulator

Equipment used to set up patient-controlled analgesia (PCA) pumps:

• Peripheral IV access
• PCA pump device
• IV tubing primed with saline
• Carbon dioxide detector cannula
• Narcotic medication

Tools for evaluation of adequate pain control in acute pain:

• Visual analog scales (VAS)
• Heft-Parker visual analog scale (HPS)
• Verbal rating scale (VRS)
• Numerical rating scale (NRS)
• Faces pain scale (FPS)
• Wong-Baker faces pain rating scale (WBS)

Personnel

An interprofessional team approach should be utilized to tailor an individualized pain management plan for the postoperative patient. The team should include the patient’s primary care provider, a pharmacist, the operating surgeon, anesthesiologist, operating room, and nursing staff involved in the case. Depending on the patient’s history or nature of the procedure, a pain management specialist, physical therapist, or psychiatrist may be included in the patient’s pain management plan as well.

In recent years, the development of Acute Pain Service (APS) groups and Enhanced Recovery After Surgery (ERAS) programs has been implemented by many facilities to help establish pain score monitoring protocols and improve intervention strategies to help manage postoperative pain within surgical wards. Theoretically, the parameters set by these programs would allow ward nurses to play a more active role in the monitoring and managing of postoperative pain, which would allow for increasingly adequate pain control.[5]

Preparation

A thorough history and physical is for the patient preoperatively to assess individual patient factors that may impact the severity of their postoperative pain and the selection of treatment modalities utilized in their pain management plan. Factors to consider when developing a postoperative pain management strategy include the type of procedure anticipated, patient age, history of chronic opioid use, and other comorbidities.[6]

Comorbid conditions to consider:

Obesity presents a challenge in opioid administration as this population is at increased susceptibility to respiratory depression or sleep apnea. Regional anesthetic techniques and the avoidance of sedative analgesics are a preferred analgesic approaches among this population.[8]

Chronic pain patients who rely on opioid treatment for relief will require amounts of opioids that exceed their baseline dose. Emphasis on multimodal therapy involving interventional anesthetic techniques and nonopioid analgesics is of particular importance among this population.[8]

In lieu of the recent opioid epidemic, evaluating patients for risk factors that may predispose a patient to opioid misuse is also an important component of the preoperative exam. Evidence suggests that patients who are female, adolescent, or older than 50 years are at increased risk of persistent opioid use. A pre-existing history of depression or illicit drug, alcohol, antidepressant, or benzodiazepine use are also at increased risk of persistent opioid use.[6]

Technique or Treatment

Many preoperative, intraoperative, and postoperative interventions and management strategies are available and continue to evolve for reducing and managing postoperative pain. The ASA published a practice guideline for acute pain management in the perioperative setting in 2012, which was reviewed and approved by the American Society of Regional Anesthesia and Pain Medicine.[2]

Below is a list of treatments utilized for the multimodal treatment of pain in postsurgical patients:

• Systemic pharmacologic therapy
• Local, Intra-articular, or topical techniques
• Regional anesthetic techniques
• Neuraxial anesthetic techniques
• Nonpharmacologic therapies- ex, cognitive modalities, physical therapy, transcutaneous electrical nerve stimulation (TENS)

Systemic Pharmacologic Therapy: Commonly used medications for postop pain control include opioids, NSAIDs and/or acetaminophen, steroids, gabapentin or pregabalin, IV ketamine, and IV lidocaine. Oral administration of opioid medication is preferable over the intravenous route. Intramuscular medications are discouraged. However, during circumstances in which parenteral route of medication administration is needed (ex, risk of aspiration, ileus), intravenous patient-controlled analgesia (PCA) is recommended. With PCA analgesia, avoid a basal infusion of opioid medication in opioid-naïve patients. The addition of acetaminophen or NSAIDs is associated with reduced opioid consumption and better pain control than using opioids alone. Gabapentin or pregabalin are recommended for administration preoperatively, especially in opioid-tolerant patients, as they have been shown to reduce opioid requirements. Due to its extensive side effect profile, ketamine is only for major surgeries, in highly opioid-tolerant patients, or opioid intolerant patients. Intraoperative IV lidocaine infusions have associations with a shorter duration of ileus and better analgesic control compared to placebo.[2] 

Local, Intra-articular, or Topical Techniques: Peripheral nerve blocks, intra-articular anesthetic injections, anesthetic wound infiltration, and topic anesthetics can be used to help with site-specific pain control. These methods are not in routine use. Their administration should be considered based on beneficial evidence.[2]

Regional anesthetic techniques: A local anesthetic with or without the addition of IV opioid medication is an option for fascial plane block, site-specific regional anesthetic injections, or in some cases epidural injections depending on the type of procedure performed. An anesthesiologist typically performs these techniques under ultrasound guidance. The use of continuous IV medication (in drip form) is preferable to single-injection techniques in cases where the duration of postoperative pain is prolonged. Intrapleural analgesia is not recommended for pain control as there is little evidence to suggest benefit, and high systemic absorption within the pleural space increases the risk of drug toxicity.[2]

Neuraxial anesthetic techniques: Typically involves an epidural injection with local anesthetic with or without the addition of IV opioid medication. May also include the intrathecal (spinal) injection of opioid medicines. Epidural analgesia may be given as a continuous infusion or as patient-controlled analgesia. These techniques are for routine use in major thoracic and abdominal procedures, cesarean sections, and hip or lower extremity surgeries. They are especially beneficial in patients at risk for cardiac or pulmonary complications, or prolonged ileus.[2]

Nonpharmacologic therapies: Examples of nonpharmacologic therapies used in pain control include cognitive modalities or mechanical modalities such as transcutaneous electrical nerve stimulation (TENS).[2]

Evaluation of adequate pain control:

The assessment of pain severity is generally accomplished using a pain scale. Acute pain, such as that experienced in the postoperative period, is most commonly measured using unidimensional pain scales. While there are many different pain scales available, the Visual Analogue Scale (VAS) is the most frequently used scale to evaluate postoperative pain. This scale involves the use of a metered line marked from 0 to 10 with word descriptions of pain at either extreme of the scale, where 0 represents “no pain” and 10 represents the “worst possible pain.”[9]

Complications

Inadequate acute pain management has numerous adverse effects on patient health, including but not limited to reduced ability to perform activities of daily living, impaired ability to sleep, low mood, and decreased libido. Not only does poor acute pain management negatively affect patient health, but it may also increase the risk of developing chronic pain.[10]

The use of opioid medication may result in somnolence, sedation, respiratory depression, urinary retention, nausea/vomiting, ileus, or pruritis.[10] An opioid overdose may result in death or disability.[6] The use of opioid medication may place a patient at increased risk of addiction and substance use disorder. Early symptoms of opioid withdrawal include anxiety, restlessness, lacrimation, runny nose, diaphoresis, insomnia, frequent yawning, and muscle aches. Late symptoms of opioid withdrawal may be more intense and include diarrhea, abdominal cramping, piloerection, nausea and vomiting, tachycardia, hypertension, pupillary dilation, and blurry vision.[6] Gabapentin or pregabalin may cause symptoms of dizziness or sedation.[2]

The bleeding risk associated with the use of NSAIDs should be considered among patients in circumstances where they are at increased risk of blood loss, such as those who had surgery on highly vascular structures (ex. tonsillectomy) versus others (ex.  cholecystectomy) when developing an appropriate pain management strategy.[1] NSAIDs also correlate with an increased risk of gastrointestinal bleeding and renal dysfunction.[2]

The use of peripheral regional analgesic techniques may result in a transient motor blockade, which could increase the risk of falls.[2]

When administering neuraxial analgesia, patients require close monitoring as respiratory depression, hypotension, and motor weakness from spinal cord compression (due to hematoma or infection) may occur.[2] Continuous intra-articular bupivacaine administration in patients who underwent shoulder surgery may increase the risk of chondrolysis.[2]

Clinical Significance

Inadequate postoperative pain control may result in adverse physiologic effects in the acute postoperative setting and increases the likelihood of developing a chronic pain syndrome. A patient’s health and well-being may further suffer as a consequence of chronic pain. Having an understanding of the pathophysiology of pain, pain reduction strategies, level of invasiveness of the procedures performed, and individual patient comorbidities and social factors can help a physician develop an optimal pain management plan that reduces the risk of these worse outcomes.[4] Moreover, optimized postoperative pain control has been shown to reduce patient suffering, reduce hospital length of stay, aids in earlier mobilization and ability to perform activities of daily living, and improves patient satisfaction.[6]

While opioid analgesic therapy continues to play a substantial role in the management of postoperative pain, the rise in injury and death due to opioid overdose among the general population warrants careful consideration of a patient’s susceptibility to the development of a substance use disorder or medication misuse before prescribing opioid therapy. Also, patients should receive information on safe storage practices and proper disposal methods of their medication upon discharge home.[1]

A multimodal approach and individualized plan for managing postoperative pain should be emphasized to help reduce opioid demand while optimizing pain relief.

Enhancing Healthcare Team Outcomes

Postoperative pain control is a complex endeavor requiring interprofessional participation that begins in the preoperative setting and continues into patient recovery. A thorough preoperative assessment of the patient by the primary care provider, nurse practitioner, operating surgeon, and anesthesiologist can aid in identifying patient risk factors and comorbidities that may influence the severity of his or her postoperative recovery period and allow for the development of an individually tailored pain regimen. A multimodal, interprofessional approach to pain control allows for safer, more efficacious pain relief in the postoperative patient as opposed to primary reliance on opioid therapy. In the immediate postoperative period, nurses play an essential role in monitoring the severity of the patient’s pain level and communicate the need for further intervention to other team members as necessary. Clinical pharmacists play an integral role in deciding about the least effective dose for patients postoperatively and provide them with adequate information about various available options, such as alternative medication suggestions and knowledge about adverse effects and interactions, in order to help them make informed decisions about their care in the postoperative period. The nurse, the provider, and the pharmacist all play a crucial role in educating patients and their families about postoperative pain control. They should ensure that they provide patients with well-written information about how to control pain, postoperatively. This interprofessional approach will drive better outcomes for postoperative pain control and increase patient quality of life. [Level 5]

Nursing, Allied Health, and Interprofessional Team Interventions

The nurse has an integral role in the management of patients who encounter postoperative pain. Educating patients about their pain and administering their medications appropriately, with the correct timing and dosage, is a core competency that all nurses should practice carefully. The nurse should assist the provider in titrating doses of pain medications, according to the dynamic changes of the patient's pain scores. The nurse should alert the provider whenever there are any untoward changes in the vital signs of the patient.

Nursing, Allied Health, and Interprofessional Team Monitoring

• Vital signs
• Validated visual analog scores
• Any untoward changes in the patient's condition
• Patient's level of activity and ambulation