Multimodal Anesthesia Is a Must

Numbing nerves around the surgical site is an essential aspect of any multimodal anesthesia regimen. Neuraxial anesthesia and peripheral nerve blocks provide superior pain relief when compared with opioid-based strategies for patients undergoing extremity surgeries or abdominal procedures, says Eric Schwenk, MD, FASA, director of orthopedic anesthesia at Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, Pa., who adds that placing drug-infusing catheters at the surgical site extends the pain-relieving effects of regional blocks.

Dr. Schwenk oversees the multimodal anesthesia program for Jefferson’s orthopedics service line, a specialty with complex procedures that often leave patients in severe pain. He says knee replacement patients receive adductor canal or femoral blocks, or local infiltration of bupivacaine at the incision site.

Opioids were never intended to be used as the cornerstone of post-op pain management practices.
— Eric Schwenk, MD, FASA

Even patients at high risk for morbidity and mortality benefit from multimodal techniques. Take, for example, knee fistula repairs on patients with major cardiovascular, peripheral vascular and renal disease. You could place supraclavicular or interscalene ultrasound-guided nerve blocks, and augment with a periarticular injection of long-acting liposomal bupivacaine at the surgical site.

“These patients have no pain intraoperatively and are discharged from the recovery room without any pain medications,” says Alan Kaye, MD, PhD, FASA, a professor in the department of anesthesiology and pharmacology, toxicology and neurosciences at Louisiana State University School of Medicine in Shreveport.

Administering numerous pain-relieving medications with various mechanisms of action treats pain at several sources and minimizes doses of the individual medications to limit potential side effects.

All total joint, GYN and spine patients without contraindications at Thomas Jefferson University Hospital receive a pre-op cocktail consisting of acetaminophen, a nonsteroidal anti-inflammatory drug (NSAID) and a gabapentinoid. “Each non-opioid agent that’s added to the mix provides an incremental analgesic benefit,” says Dr. Schwenk.

Dr. Schwenk points to agents in the developmental pipeline, including a novel formulation of bupivacaine and the anti-inflammatory meloxicam that promises to provide long-lasting pain relief, and newer opioid formulations, including sublingual sufentanil, that rapidly treat pain without the lasting impact of traditional opioids like morphine and hydromorphone.

Short-acting opioids are useful for managing post-op pain, notes Dr. Kaye, but should not be sent in alone to battle pain. He instead says you should tap into the pain-relieving potential of these commonly used medications, which commonly serve as the basis for perioperative cocktails:

• Ketamine has gained a resurgence as an opioid adjunct after it was shown to be an effective agonist of NMDA receptors, which play an important role in amplifying pain sensations. Research has shown ketamine’s positive effect on patients with chronic pain and opioid dependency.
• Gabapentin and pregabalin inhibit channels in the central nervous system that are upregulated during surgery and shut down excitatory neurotransmitters in the central nervous system. These drugs have been shown to be effective parts of opioid-sparing medication regimens, especially in patients who are expected to experience severe post-op pain, and should be administered at least 2 hours before surgery to reach maximum effect. An important warning: Large doses of gabapentin can cause respiratory depression and should be avoided.
• Alpha-2 agonists possess pharmacological properties — sedation, hypnosis, anxiolysis, sympatholysis and analgesia — that make them useful agents of a multimodal pain regimen. Clonidine and dexmedetomidine have been shown to reduce opioid consumption after surgery. Another warning: Both drugs have a negative effect on blood flow, and can cause bradycardia and hypotension.
• IV lidocaine has analgesic, antihyperalgesic and anti-inflammatory properties, and has been shown to help manage pain, shorten post-op stays, improve bowel function and lower PONV rates in abdominal surgery patients.
• IV NSAIDs and acetaminophen decrease the release of proinflammatory and pain-augmenting mediators at peripheral nerve sites. Administering these agents after surgery has been shown to decrease opioid consumption. Current clinical evidence fails to show one drug is more effective than the other, but does indicate using both in combination provides the greatest analgesic effect.

In March 2018, Dr. Memtsoudis published a study that compared the outcomes of 1,028,069 total knee patients and 512,393 hip replacement patients who underwent surgery at 546 facilities across the country and received opioids only or multimodal therapies to manage post-op pain. Using more than 2 methods of pain relief in hip and knee replacement patients who didn’t receive opioids reduced post-op opioid prescriptions by up to 18.5% and resulted in fewer complications and shorter lengths of stay, according to the research.

Importantly, 85% of patients involved in the study received multimodal anesthesia. The study also showed NSAIDs and COX-2 inhibitors caused the greatest reduction in opioid prescriptions and complication risks. Dr. Memtsoudis was encouraged by the results, but he won’t be satisfied until all patients — in his health system and beyond — benefit from multifaceted attacks on pain.

“We’ll get there,” he says, “by identifying reasons providers are not using multimodal anesthesia and, when they are using it, providing rationale and evidence regarding the modalities and drugs involved. “Pharmaceutical companies push the use of promising new drugs with novel mechanisms of action and formulations,” adds Dr. Memtsoudis, “but there is little clinical evidence showing they work any better than established medications.”