Effects of different administration routes of esketamine on postoperative hyperalgesia in elderly patients undergoing laparoscopic gastrointestinal tumour surgery: a single-centre, prospective, randomised, double-blind, controlled trial

For many older adults facing surgery to remove tumors from the stomach or intestines, the procedure itself is often a triumph of modern medicine. Laparoscopic techniques allow surgeons to operate through tiny incisions, reducing recovery time and physical trauma. Yet, even with these smaller cuts, the body still reacts to the stress of the operation and the carbon dioxide used to inflate the abdomen. This stress can trigger a complex biological response where the nervous system becomes overly sensitive to pain. This condition, known as hyperalgesia, means that a touch that should feel mild might register as sharp or burning. While doctors often use strong painkillers called opioids to manage this, there is a catch: using too much of these drugs can sometimes make the nervous system even more sensitive, creating a cycle where patients need more medication to feel the same relief, yet feel more pain. Finding a way to break this cycle without causing side effects like confusion or breathing problems is a major goal for surgeons and anesthesiologists treating elderly patients.

In a recent study conducted at a hospital in Inner Mongolia, researchers set out to solve a specific puzzle regarding how to best use a drug called esketamine to prevent this heightened pain sensitivity. Esketamine is a powerful pain reliever that works differently than opioids; it blocks specific receptors in the brain that are involved in amplifying pain signals. While doctors knew that esketamine could help, they did not know the best way to give it to elderly patients. Should it be pumped slowly and steadily into the bloodstream throughout the surgery, or should it be given in a quick burst at a specific moment? To answer this, the team enrolled ninety-nine elderly patients, all between the ages of sixty and seventy-six, who were scheduled for elective laparoscopic surgery for gastrointestinal tumors. The patients were randomly divided into three groups to test different approaches. One group received a steady, continuous drip of esketamine starting before the surgery and continuing until thirty minutes before it ended. A second group received the same starting dose but then got a single extra shot of the drug thirty minutes before the surgeon closed the wound. The third group served as a control, receiving standard pain management with a different drug called sufentanil and a saline solution instead of esketamine.

The results of the study revealed a clear winner in the race for better pain control. The patients who received the continuous drip of esketamine fared significantly better than those who received the single extra shot or the standard care alone. When researchers measured how much pressure was needed to cause pain on the skin near the incision and on the forearm, the continuous drip group showed the highest resistance to pain, meaning their nerves were less sensitive. This group also required far less opioid medication during and after the surgery. In fact, they asked for fewer doses of pain relief through their patient-controlled pumps and reported lower pain scores at twenty-four and forty-eight hours after the operation. Perhaps most importantly for older patients, this group experienced fewer side effects. They were much less likely to suffer from nausea and vomiting, and they had fewer episodes of sudden, severe pain that required extra medication. The group that received the single extra shot of esketamine did better than the control group, but they did not perform as well as the group receiving the steady drip.

The study also addressed safety concerns that often accompany the use of drugs like esketamine in the elderly. There was a widespread worry that these medications might cause confusion or delirium after surgery, a serious complication for older adults. However, in this trial, not a single patient in any of the three groups developed postoperative delirium. The researchers found that the continuous method of administration kept the level of the drug in the blood stable, which likely prevented the peaks and valleys that can sometimes lead to side effects. While the single dose method offered some protection, it left gaps in coverage as the drug wore off, potentially allowing pain signals to flare up again. The steady infusion, by contrast, maintained a constant shield against these signals. The findings suggest that for elderly patients undergoing this type of major abdominal surgery, a slow, steady infusion of esketamine is a superior strategy. It not only keeps pain at bay more effectively but also reduces the need for other strong painkillers and lowers the risk of unpleasant side effects, offering a clearer path to recovery without the fog of confusion.