Perioperative Management of Patients With Substance Use Disorders

NEW ORLEANS—Substance use disorders (SUDs) are not uncommon among surgical patients, so anesthesiologists need to be aware of the clinical implications and be prepared to manage patients who might experience withdrawal. They are also sometimes in a position to help patients make changes to lessen or quit their substance use.

During a session at the 2022 annual meeting of the American Society of Anesthesiologists, several experts discussed strategies for managing patients whose substance use may have consequences for their perioperative care and long-term health.

Cocaine and Other Street Drugs

It is important to recognize, diagnose and treat acute intoxications caused by SUDs, said Karsten Bartels, MD, PhD, a professor of anesthesiology, the vice chair of research and the Robert Lieberman Endowed Chair in anesthesiology at the University of Nebraska Medical Center, in Omaha, but he acknowledged that this can be a double-edged sword.

“Patients sometimes get delays in treatment because of a positive urine test for cocaine, but by the time cocaine is still detectable in urine, the patient’s systemic levels may be clinically insignificant. We learned from the COVID-19 pandemic that delaying and canceling surgeries comes at a high price, especially for patients facing health disparities and who are likely to suffer disease progression,” Bartels said.

The risk for an adverse coronary event in surgical patients with a positive urine screen for cocaine use is low. A study that investigated outcomes in 328 asymptomatic patients with a history of cocaine use and undergoing elective surgery found no difference in the proportion of intraoperative hemodynamic events between cocaine-positive and cocaine-negative patients by urine tests (Anesth Analg 2021;132[2]:308-316).

“We must carefully assess patient symptoms and their EKG prior to making the decision to cancel a surgical procedure based on a positive urine screen for cocaine. The costs of delaying a surgery are not purely financial—there’s a health cost to the patient due to not receiving surgical care,” Bartels said.

Additionally, major elective surgeries may present an opportunity to encourage patients to consider long-term treatment for what is often a chronic condition, he said.

“Some might say anesthesiologists need to take care of patients during the operation and don’t have the time or resources to implement long-term outcomes, but I would argue that’s not true.”

In the United States, the numbers of psychiatrists, counselors, social workers and psychologists are expected to fall by more than 140,000 in the next two years. So, anesthesiologists should treat SUDs and mental health issues the same way they already take care of other medical issues, he said.

“For patients who come in for urgent CABG [coronary artery bypass graft], we routinely provide guideline-concordant medical treatment prior to surgery and in the ICU,” Bartels added. “I think we need to leverage that moment of interacting with the patient in the time of major surgery to also treat and engage them in terms of mental health and SUDs.”

There is some research suggesting that screening, brief intervention and referral to treatment (SBIRT) can have meaningful long-term outcomes. A study found that 25% of patients who received a perioperative SBIRT intervention for smoking cessation adhered to cessation at one year, compared with 8% of those who did not undergo the intervention (Anesth Analg 2015;120[3]:582-587).

“We need to reduce the stigma of perioperative SUDs and mental health diagnoses,” Bartels noted. “In practice, we might be the only physician that a patient talks to for an extended period during their hospitalization, and we need to leverage that opportunity.”

Cannabis Use and Effects

Cannabis use is on the rise, which is important for anesthesiologists to be aware of because every organ system they monitor can have a potential interaction with the substance, said Karim Ladha, MD, an associate professor at the University of Toronto and St. Michael’s Hospital, in Ontario.

“When you think about the central nervous system, it can affect anesthetic requirements and postoperative analgesic requirements; for the heart, myocardial infarction, heart rate, blood pressure and arrhythmias; for the lungs, increased airway reactivity and underlying lung disease; in the liver, enzymes that affect drug metabolism; it also potentially decreases gastric motility and, from a hematologic perspective, may alter coagulation patterns,” Ladha said.

But much of the data showing these interactions have been highly circumstantial. Many people use cannabis, and very few of them have issues with coagulation.

“The problem is that we treat cannabis users the same whether they use cannabis 10 times a day or once a day or once a month. The reality is, this is much more heterogeneous than we appreciate. We simply don’t have the data to understand these nuances,” Ladha said.

In the absence of data, Ladha and his colleagues developed a consensus guideline using a Delphi process. “The key thing in the preoperative period is to ask about cannabis use. Amount matters,” he said. But patients often struggle to estimate how much they’re ingesting, especially given the variety of ways it can be dispensed. “So, in general, we typically ask if they’re using cannabis more than two or three times a day,” he said.

The next question is whether patients should be weaned off cannabis before a procedure. “Prior, non–evidence-based guidelines said all patients should stop. But if patients are taking cannabis for therapeutic purposes—such as anxiety or pain management—having them stop could worsen those conditions and make their perioperative course more complicated to manage,” Ladha said. There is also the risk for withdrawal in patients with a cannabis use disorder.

The consensus group agreed that if there were more than seven days before surgery, consider weaning or stopping cannabis. Less than one day before surgery, do not stop. If it’s one to six days, “it’s up to the clinician to use their judgment,” Ladha said.

As for intraoperative and postoperative considerations, some data indicate that there is an increased sedation requirement, but again, these studies have been mixed. “I think there’s enough anecdotal evidence and clinical experience to suggest that heavy cannabis users will likely have increased anesthetic needs,” Ladha said.

Lastly, some patients may experience cannabis withdrawal syndrome, which is established DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) diagnostic criteria and can appear immediately after surgery. No standardized treatment guidelines exist, but the evidence to date suggests that THC analogs, such as dronabinol or gabapentin, may be helpful, he said.

“We’re often asked if we should substitute an analog for a patient on cannabis. This is something we take on a case-by-case basis. If someone is going to be in the hospital a long time and they are a heavy cannabis user, we will give them a drug like nabilone—which is synthetic THC—as a substitute,” Ladha said.

Alcohol Use Disorder and Withdrawal

Alcohol withdrawal syndrome (AWS)—brought on by the abrupt reduction or cessation of alcohol consumption by someone who has been drinking heavily for a long time—can be dangerous and potentially life-threatening.

While it remains a clinical diagnosis according to DSM-5 criteria, assessment can be made via the Clinical Institute Withdrawal Assessment for Alcohol–Revised (CIWA-AR), which measures withdrawal symptoms, such as agitation and tremors, by assigning each a point value.

“We use the CIWA-AR to assess how early we can pick up on patients at risk for AWS, and how quickly we can start treating for the more serious symptoms, especially when we don’t know if a patient has a history of alcohol abuse. Patients who score on the higher end of the scale—15 to 20 points—definitely need medications,” said Ana Costa, MD, an anesthesiologist at Stony Brook University Hospital, in New York. Benzodiazepines are the first-line treatment, especially longer-duration agents, she added.

Regarding perioperative management, the most important thing anesthesiologists can do is to detect patients who could benefit from a tempered reduction or cessation of alcohol prior to surgery, she said.

“For elective cases, there’s an opportunity to help these patients stop alcohol via pharmacological treatment, education and therapy—three mechanisms that have been shown to be the most effective way to help patients stop drinking. If patients can stop drinking and fully [detoxify] before surgery, they will probably do better,” Costa said.

The challenge, of course, is identifying patients who have an alcohol use disorder. “A very thorough history is essential. Elevated liver enzymes are a red flag; or when they have a slew of medical problems, I always ask for any alcohol or drug intake,” Costa said. Screening tools, such as the Alcohol Use Disorders Identification Test, also can help find patients who could benefit from preoperative treatment.

Postoperatively, the goal of managing AWS is alleviating symptoms and correcting metabolic derangements. “When patients come to us urgently or in an emergency, there’s not much we can do prior to surgery. But after surgery, we can dispense benzodiazepines to control psychomotor agitation and prevent progression to more severe withdrawal, as well as supportive care with IV fluids and nutritional supplementation,” Costa said.

In addition, propofol may be used as an adjuvant in patients with resistant AWS, she added, noting that propofol is associated with longer duration of mechanical ventilation and extended hospital length of stay. “This might be attributed to more resistant cases of AWS or to the nature of mechanical ventilation,” Costa said.

—By Monica J. Smith

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Bartels was the principal investigator for the AHRQ-funded EQUIPPED grant, the NHLBI-funded COR-PM conference and the NIH-funded Improving Opioid Prescription Safety After Surgery grant. Costa reported no relevant financial disclosures. Ladha is a co-principal investigator on an observational study on medical cannabis funded by Shoppers Drug Mart.