Adequate and appropriate pain management is a basic human right, as stated by the World Health Organization (WHO) and the International Association for the Study of Pain (Brennan, Carr, & Cousins, 2007). Postsurgical pain is unique and multivariate, requiring individualized care plans to ensure that the pain is treated and managed well. Unrelieved pain in the postoperative period may lead to negative sequalae including, but not limited to, increased rehabilitation postoperatively as well as persistent postoperative pain (PPP) development. The following chapter will outline postoperative pain, its assessment, management, and special considerations.

The way in which pain is processed, and experienced, depends on inherent characteristics of the individual and the type of the procedure itself. To understand postoperative pain, the type of pain must first be understood. Nociceptive pain is the most common pain experienced by individuals and is generally the pain that is experienced postoperatively. As defined by the International Association for the Study of Pain (1994), nociceptive pain is defined as “pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors.” Nociceptors are “high-threshold sensory receptors of the peripheral somatosensory nervous system, that [are] capable of transducing and encoding noxious stimuli.” When there is an insult to tissue, such as with a surgical procedure, pain processing involves a feedback response as detailed in Figure 10-1. In addition to understanding the type of pain, distinction must be made concerning the classification of pain dependent on duration of symptoms, that is,
acute versus chronic. Acute pain is short in duration and generally resolves once the initial insult has healed. Contrarily, chronic pain lasts longer to heal than the initial insult, lasting months to years in duration. Acute postoperative pain is a fairly common and expected phenomenon.

PPP is defined as pain that lasts beyond the initial procedural insult, greater than 8 weeks (Macrae, 2001). Its prevalence depends on the type of procedure, with orthopedic procedures increasing this risk significantly. Moderate to severe postsurgical pain in the immediate postoperative pain period is a risk factor for PPP (Kehlet, Jensen, & Woolf, 2006; Perry, Starkweather, Baumbauer, & Young, 2018). For this reason, it is vital to ensure that healthcare providers are adequately assessing and managing postoperative pain throughout the perioperative period, including preoperative and postoperative, acute and chronic.

In understanding those who are at increased risk of PPP, a biopsychosocial approach should be taken when assessing patients preoperatively. In using this approach, the individual’s entire being is considered. Table 10-1 outlines those who may be at increased risk for transitioning from acute to chronic pain states.

Assessing pain throughout the perioperative period is vital to preventing long-term complications, including PPP. Relieving pain, while reducing the incidence of pharmacologic side effects, is of the utmost importance. Appropriate assessment of the pain both preoperatively and postoperatively will assist in ensuring that the pain trajectory is well managed. In adult populations, there are several assessment tools that may be used dependent upon the individual’s cognitive function. As always, the gold
standard of pain assessment is patient self-report, and having a first-hand account of the patient’s pain is vital. Choosing the correct scale is the initial point of assessment, done in conjunction with a comprehensive assessment. Conducting a pain interview using a pneumonic such as PQRSTU (Table 10-2) may be useful to ensure that the entire pain experience is captured and adequately assessed. Generally assessed on a numerical scale of 0 to 10, other instruments such as a visual analog scale may be used in those who are nonverbal. In children under 7 years of age, or unable to conceptualize the 0 to 10 concept, it may be helpful to utilize a visual scale such as Wong-Baker FACES pain rating scale (Wong-Baker Faces Foundation, 2016). If one is unable to provide a verbal account of pain, such as in the case of children or adults with neurocognitive impairment, it may be appropriate to use behavioral scales, such as the Faces, Legs, Arms, Crying, and Consolability (FLACC) scale (Merkel, Voepel-Lewis, Shayevitz, & Malviya, 1997). Though the gold standard is self-report, a proxy may be necessary in those who are unable to communicate (i.e., a caretaker or parent).

Figure 10-2 outlines the WHO pain management ladder, providing a list of commonly used medications. It is important to note that this list is not inclusive of all medications and adjuvants. Initially created as a guide for those treating cancer pain, the WHO ladder has now been implicated for use in all types of pain, including postoperative pain (Gupta et al., 2010; Ventafridda, Saita, Ripamonti, & De Conno, 1985). The ladder differentiates mild, moderate, and severe pain states, with recommendations for the type of analgesic to be prescribed and subsequently administered. Each step builds upon each other as the pain persists. Step 1 involves the use of a nonopioid, step 2 may include a weak opioid in conjunction with a nonopioid, whereas step 3 escalates utilizing strong opioids with addition of nonopioids. At all stages of the ladder, an adjuvant and/or complementary alternative medicine (CAM) may be used. Considering the extensive nature of surgical procedures, it is not uncommon for pain management to begin at step 3, severe pain, in the immediate postoperative period and be titrated as appropriate to the patient’s tolerance and pain level. Adequate titration of analgesics, dependent on the patient’s pain, may improve long-term outcomes, such as decreased incidence of opioid dependence and withdrawal.

Opioids are likely be the first-line analgesic choice considering the severe intensity of pain in the immediate postoperative period. Inherently, humans possess endogenous opioids and their respective receptors. Exogenous opioids, those that healthcare providers administer (i.e., morphine), work by binding to endogenous opioid receptors. In doing so, the opioid essentially alters pain modulation through the peripheral nervous system and central nervous system (CNS). There are several formularies of opioids, including oral, intravenous, transdermal, and rectal (Garimella & Cellini, 2013). The long-standing opioid of choice continues to be morphine, which is classified as a strong opioid. All other analgesics are compared to morphine via morphine equivalents (Pathan & Williams, 2012). Other strong opioids that may be comparative to morphine include fentanyl and hydromorphone (Table 10-3). These analgesics are synthetic derivatives of morphine, which make them more potent with shorter onset of action and half-lives (Garimella & Cellini, 2013).

Though opioids are very useful in managing severe postoperative pain, it is important to note their increased incidence of side effects. These side effects may include pruritus, opioid-induced constipation, opioid-induced hyperalgesia (OIH), and, most importantly, respiratory arrest. It is also important for providers to be aware of the risks of OIH. The rotation of opioids from different structural classes may also be helpful in this matter (Bottemiller, 2012). In addition, close monitoring of respiratory rate and depth is vital to ensuring the safety and efficacy of opioid administration. While administering morphine in the inpatient setting, sedation scales such as the Pasero Opioid-Induced Sedation Scale are useful in ensuring that the patient is tolerating the analgesia as well as providing recommendations for those who are not (Pasero, 2009). If the patient is deemed to be in respiratory depression or experiencing hypoxia, the opioid reversal agent is Naloxone, an opioid receptor antagonist.

In 2001, the Joint Commission saw an undertreatment of pain in individuals. In response, guidelines outlining pain assessment and reevaluation of the pain were created (Phillips, 2000). To facilitate change in practice of more thorough and frequent assessment and reassessment of pain, the Joint Commission referred to pain as the sixth vital sign. An unintended consequence of the focus on providing adequate treatment of pain was that the rate of opioid prescribing not only increased, but also precipitated the widespread fear of opioids, lack of consumer and prescriber education, inaccurate and inconsistent prescribing practices, as well as increased misuse
and abuse. Statistics from the current opioid epidemic both nationwide and at the state levels are enough to raise concern regarding opioid prescribing in the hospital setting . It is important to note that the majority of opioid use stems from opioids that have been legally prescribed and obtained. In 2015, there were 12.5 million people nationwide misusing prescription opioids, which subsequently cost the United States $78.5 billion (United States Department of Health and Human Services, 2017).

Depending on the patient’s age, mental status, and cognitive function, the use of patient-controlled analgesia (PCA) may be beneficial in their treatment plan. PCA provides a way to secure intravenous or epidural analgesic medication at the bedside of the patient and the pump can be programmed to deliver continuous infusion or intermittent bolus dosing that is activated by the patient on a scheduled dosing scheme. Not only does a PCA afford patient autonomy but allows for continuous pain control. Generally, strong opioids, such as morphine, hydromorphone, and fentanyl, are used in PCA pumps. The modes in which PCA pumps can be set include continuous and demand or demand only. Lockout intervals should be appropriate and promote safe dosing while decreasing the negative side effects of opioids, such as sedation, cardiovascular collapse, hypoxia, and/or respiratory arrest. Adequate assessment of individuals who may be most appropriate for PCA analgesic is vital to ensuring its overall efficacy. PCA pumps are not appropriate for young children and/or those who are cognitively delayed. The individual must be able to conceptualize the indications of the PCA pump itself and its ability to relieve pain.

Prior to initiating a PCA pump for a patient, adequate analgesia must already have been provided. It is not practical to start the pump if a patient is already experiencing pain, especially moderate to severe in nature. Presurgical education is necessary when introducing PCA pumps within the surgical plan. Education must include not only the patient but also the family. Such education must include explicit directions that only the patient should push the PCA button to deliver the opioid analgesia regardless of the circumstances.