A Medical Device Daily

A study reported at the annual meeting of the American Society of Anesthesiologists (ASA; Park Ridge, Illinois) which ended Wednesday in San Francisco, said that administration of the drug pregabalin before and after total knee replacement (TKR) surgery “significantly decreased” patient pain while both increasing and expediting post-procedure mobility.

Asokumar Buvanendran, MD, director of orthopedic anesthesia and associate professor of anesthesiology at Rush University Medical Center (Chicago), conducted the study with 60 TKR patients in two groups. One group received 300 mg of the anti-convulsant drug two hours before surgery and 150 mg twice a day for 14 days following the procedure. The other patients were given placebos at the same intervals.

The study found a significant decrease between the pregabalin and placebo groups in pain medication consumption in the 32 hours following surgery. The pregabalin group also consistently reported pain levels between 2 and 4 (on the standard scale of 1 to 10, with 10 being the most severe) following the TKR procedure.

Buvanendran said the patients’ range of motion (ROM) following surgery was higher in the pregabalin patients at hospital discharge (normally on the third day following surgery) — an average of 84 degrees compared to 76 degrees among the non-pregabalin patients. He said it usually takes a TKR patient a full week to reach that level.

Administration of pregabalin “decreased post-operative analgesic requirements while improving function,” Buvanendran said, adding that the ROM improvements are “especially important.”

Noting that at 83-degree ROM a patient can climb stairs, he said, “When you can walk up and down stairs, it makes a huge difference in patient quality of life.” And the improved range of motion also allows patients to complete post-surgical rehabilitation more quickly.

In another study presented at the meeting, the use of a nicotine patch identical to those used to help smokers reduce their dependency was shown to reduce pain in men after prostate removal surgery.

Ashraf Habib, MD, associate professor of anesthesiology and director of quality improvement at Duke University Medical Center (Durham, North Carolina), conducted a study involving 90 non-smoking men about to undergo a radical prostatectomy. Each received a 7 mg nicotine patch or an identical placebo patch before anesthesia and surgery.

After surgery, each patient was able to access morphine through a self-controlled device, and the patients who received the nicotine patch self-administered “significantly less” morphine in the post-operative period, Habib said. “The study suggests that the nicotine patch has a useful effect in improving pain relief after surgery.”

Several previous studies have shown the pain-relief benefits of morphine. In one study, a small dose (3 mg) of nicotine was given post-surgically via a nicotine spray to hysterectomy patients. Those patients reported less pain and less need for morphine.

Habib said future studies could determine whether nicotine is better administered in a patch or as a spray, as well as the relative effectiveness of nicotine “in smokers vs. non-smokers and women vs. men.”

And, he added, different doses of the patch could be tested to identify the ideal amount of nicotine to produce optimal pain relief with little or no side effects.

A third study presented during the meeting indicated that wrist surgery patients who received a regional anesthetic experienced less pain and more quickly regained use of their hand and wrist than those given general anesthesia.

Andrew Rosenberg, MD, chairman of the department of anesthesiology at New York University Hospital for Joint Diseases (New York), studied more than 200 patients of similar age, gender and socioeconomic status who received either a regional block anesthesia or general anesthesia. Three months after surgery, the patients who had received a regional block had less pain and better movement of their wrist and hand than those who received general anesthesia.

Rosenberg said there are several possible reasons for the improved outcome. “First, some physicians believe that if you block or numb nerves before surgery starts, you might prevent the release of certain inflammatory and pain chemicals that usually get released with injury.”

Another theory, he said, is that pain relief immediately after surgery with a regional block may provide overall and long-term benefits. Finally, regional anesthetic may block other nerve fibers in addition to those that signal pain from the arm to the brain, which can cause a lot of pain and swelling following surgery.

Regardless of the reason for the diminished pain and improved mobility, Rosenberg said the results “are important to consider when deciding what type of anesthesia to have for repair of a wrist fracture.”

Also at ASA, Masimo (Irvine, California) launched its Patient SafetyNet, a new remote monitoring and clinician notification system, and showcased its upgradeable Rainbow SET technology platform.

The company described the Patient SafetyNet as “an easy-to-use system that combines the ‘gold standard’ performance of Masimo Rainbow SET pulse oximetry with wireless clinician notification via pager to provide an unprecedented level of safety to patients on general care floors, where nurse-to-patient ratios preclude the level of direct surveillance required and recommended to preempt sentinel events.”

The company said that numerous standards bodies — including the Joint Commission (JCAHO), the American Society of Anesthesiologists, the Anesthesia Patient Safety Foundation and the Institute for Healthcare Improvement — are calling for improved patient safety standards on general care floors.

The company said the Patient SafetyNet is “specifically designed to keep at-risk patients safe on general care floors by connecting them to qualified caregivers quickly, easily and accurately.”

It said that when a Patient SafetyNet-monitored patient is in respiratory distress, “meaningful and actionable” alarms are generated by the Masimo bedside monitor and sent wirelessly to designated clinicians for review and response. “As a result, appropriate clinical intervention can be initiated quickly, preempting sentinel events — defined by the JCAHO as ‘an unexpected occurrence involving death or serious physical injury not related to the natural course of the patient’s illness’.”