In 2010, nearly 12 million Americans reported nonmedical use of prescription painkillers in the past year. As the use and abuse of opioids increases, the likelihood of an anesthesiologist these patients during clinical practice also will increase. As both illegal and prescription use of opioids increases, anesthesiologists will encounter more patients exhibiting opioid tolerance. Secondly, as abusers of opioids seek treatment for their addiction, the numbers of patients receiving long-term opioid therapy for their addiction also will increase.
All anesthetic plans can be divided into preoperative considerations, intraoperative management, and postoperative recovery and analgesia. For patients with known or suspected opioid abuse, this strategy is no different. The interviewing clinician will benefit from realizing that many patients with a history of abuse or dependence on prescription opioids will be evasive about that history or will attempt to minimize their use of these drugs. A helpful strategy when collecting the patient history is to focus on specific questions while preserving a nonjudgmental environment. When possible, the interviewer should determine the time of the last dose of opioids and, if applicable, who is prescribing these medications.
Drug screening, specifically urine drug screening, is an important tool in obtaining objective information about a patient’s use of opioids. However, these tests have several important limitations. Immunoassay screening, which is the most common urine drug screen, can detect the presence of specific opioids and their metabolites but frequently returns false-positive results and typically findings must be confirmed by gas chromatography—a time-consuming process. Drug testing can provide useful objective information as long as clinicians are aware of these limitations.
The clinician will likely encounter patients who have been taking opioids chronically. These include the opioid agonists methadone and buprenorphine-naloxone, as well as the opioid antagonist naltrexone. Having a working knowledge of these medications is helpful in understanding their anesthetic and analgesic implications.
Patients on long-standing prescription opioids can be directed to take these medications as they normally would on the morning of surgery. Patients at risk for or entering withdrawal can have their symptoms managed. Clonidine is commonly used to treat symptoms of opioid withdrawal and can be given as a starting dose of 0.1 mg twice daily. Other medications, such as loperamide, also can be administered to target specific withdrawal symptoms.
Intraoperative management of patients with opioid dependence or abuse relies heavily on three areas: managing intoxication, preventing or treating withdrawal, and achieving effective analgesia. Although many patients will not present for elective surgery when they are acutely intoxicated, urgent or emergent situations involving these patients often occur. In these incidents, monitoring respiratory rate and oxygen saturation is critical. Antagonist therapy should be reserved for patients with potentially life-threatening respiratory depression, as precipitating withdrawal in such a patient may make both anesthetic and analgesic management more difficult.
Analgesia strategies for patients ...