Opioid Dependence by Heath B. McAnally

Author:Heath B. McAnally
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

Perioperative Opioid Therapy

A special subset of acute pain deserving unique consideration is perioperative pain, the majority of which is associated with elective procedures that can be anticipated and planned for. Perioperative pain (POP ) is virtually universal, and the literature consistently reports a prevalence of chronic postsurgical pain (CPSP) in the neighborhood of 50%. Neuropathic pain and central sensitization are believed to represent a significant component of most CPSP states [20–24]. Increased POP intensity/poor (immediate) postsurgical pain control has been understood to be a risk factor for CPSP for decades and confirmed recently by robust investigations [25–27]. Increased POP also shares psychological confounders which are strong independent predictors of increased CPSP [26–31].

Opioids have enjoyed perioperative (including pre- and intraoperative) use for over 150 years in conjunction with sedative-hypnotic agents to facilitate surgery as well as relieve some of the severe associated pain. The concept of “balanced anesthesia ” taught to every anesthesiologist in their training includes (generally intravenous, intraoperative) opioids within the admixture, as these agents have historically provided unparalleled efficacy in analgesia and sympatholysis, with widespread availability and low cost. The concept of preemptive analgesia (PEA) was first proposed by Dr. Patrick Wall (of gate theory fame, as discussed in the previous chapter) [32] and later developed more fully by his protégé Dr. Clifford Woolf, who demonstrated that prevention of central sensitization underlies the mechanism of PEA [33]. In essence the theory states that adequate analgesia surrounding a traumatic insult (e.g., surgery) can prevent the chronification and amplification too often seen with a surgical operation. Initial interpretation and application of PEA were confined to the preoperative (including immediate pre-incision moment) period and focused on blunting or eliminating nociceptive input by means of systemic analgesics (e.g., intravenous opioids or ketamine) and/or local anesthetic. Despite widespread enthusiasm for the concept, the data did not support the efficacy of this (exclusively pre-incisional) strategy until expanded awareness of the ongoing contribution of low-level C-fiber transmission from the surgical wound is critical in maintaining the sensitized state, necessitating ongoing analgesia until adequate healing occurs [33]. Opioids have continued to represent the lion’s share of PEA practice, as ongoing adequate local anesthetic blockade is technically challenging and logistically difficult and prolonged ketamine use (or rather cumulative excess) confers significant dissociation and psychosis. However, it has been recognized for quite some time, well prior to the onset of the current opioid epidemic, that:Until an opioid without side effects is available, opioid sparing strategies need to be adopted to ensure sufficient analgesia without sedation and nausea…. [33]

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