OCTOBER 4, 2023
Originally published by our sister publication Anesthesiology News
HOLLYWOOD, Fla.—Anesthesiologists concerned about the risk for infection following regional anesthesia will likely draw comfort from the results of a new report.
The review found that although the odds of infectious complications following neuraxial anesthesia were exceedingly low, the rate of such complications was relatively higher with the implementation of peripheral nerve block catheters. Nevertheless, the researchers
Originally published by our sister publication Anesthesiology News
HOLLYWOOD, Fla.—Anesthesiologists concerned about the risk for infection following regional anesthesia will likely draw comfort from the results of a new report.
The review found that although the odds of infectious complications following neuraxial anesthesia were exceedingly low, the rate of such complications was relatively higher with the implementation of peripheral nerve block catheters. Nevertheless, the researchers recognized the need for more evidence in the field to help put the issue to rest.
“Infectious complications following regional anesthesia may be rare, but when they happen they can be devastating to patients and lead to increased morbidity and in certain cases, even mortality,” said Breethaa Janani Selvamani, MD, a fellow in regional anesthesia and acute pain medicine at the University of Iowa Hospitals and Clinics, in Iowa City. “And while we perform these blocks routinely the incidence of these complications varies widely among existing studies, and their risk therefore remains uncertain.
“We need better estimates of their incidence,” Selvamani continued. “But given that these are rare events, it is harder to estimate this incidence without a large patient sample. So, we wanted to pull data from several studies over the past three decades, to see what it revealed.”
To that end, the researchers searched the Embase, PubMed and Cochrane databases for relevant articles, which yielded a total of 6,783 abstracts for eligibility review, all of which were published between Jan. 1, 1990 and Dec. 12, 2022. Of these, 415 abstracts were selected for full-text review. Following the application of various exclusion criteria, a total of 54 studies were selected for data collection and analysis.
Reporting at the 2023 spring meeting of the American Society of Regional Anesthesia and Pain Medicine (abstract 4041), Selvamani noted that the sample size of included studies examining infectious complications after neuraxial anesthesia ranged from 75 to 3,833,620. Among these, the overall rate of infectious complications following neuraxial anesthesia was 10 in 100,000 (95% CI, 5-14 in 100,000). Specifically, the rate of serious central nervous system infections (which included meningitis, arachnoiditis, encephalitis and spinal epidural abscess) was three in 100,000 (95% CI, 1-4 in 100,000) following epidural anesthesia and two in 100,000 (95% CI, 0-3 in 100,000) following spinal anesthesia.
“One thing we noticed while analyzing the studies was that there was wide variation in the way infections were defined; there were no standardized definitions,” Selvamani said in an interview with Anesthesiology News. “Some studies included things like tenderness and redness in their definition, while others did not.”
Analysis of peripheral nerve catheters, on the other hand, found that sample sizes varied between 29 and 4,270. Here it was found that the overall infectious complication rate was 1.528% (95% CI, 0.958-2.098/100 patients).
“That seemed quite high to us,” Selvamani said. “Nevertheless, the number of studies that examined peripheral nerve catheters was limited. In addition, it’s worth mentioning that we did not look at single-shot peripheral nerve block catheters, only continuous catheters, once again because of limited data in the literature.”
Given such shortcomings, the investigators noted the need for a standardized definition in identifying infectious complications in studies, as well as more research in the area, particularly given the frequency with which neuraxial anesthesia is currently performed.
In the meantime, the researchers urged continued diligence among their anesthesiologist colleagues when it comes to infection control practices.
“Yes, the infection rate we found for neuraxial anesthesia was low, but these are preliminary data and more work is needed,” Selvamani said. “So, perhaps our current infection control practices are sufficient, but since complications from these infections can be devastating, any further progress we can make in understanding disease causation would be great.”
In a related study presented here (abstract 4195), researchers at the institution performed a systematic review of case reports with an eye toward evaluating patient and procedure risk factors for infectious complications following regional anesthesia. That effort included 116 case reports and case series, and found that diabetes and immunocompromised states were the two primary patient risk factors for such infections.
The most common procedural risk factor for infection, on the other hand, was multiple attempts at performing regional anesthesia, although adherence to perioperative aseptic technique was also found to play an important role. While the analysis found that most patients experiencing an infectious complication recovered with no long-term morbidity, devastating outcomes—including mortality—were noted in patients receiving epidurals, spinals and peripheral nerve blocks.
“Most patients did not have any risk factors or procedural risk factors, hence the importance of environmental impact and sterility,” Selvamani explained. “Yet an important takeaway from that study is that infections can occur without any risk factors, so we need to always be aware of that possibility.”
As Sebastian Schulz-StÜbner, MD, discussed, the findings confirm previous observations and analysis, although he noted that minor cases of infection might be underreported in the literature and comprehensive surveillance systems using standardized definitions are still lacking.
“We can only speculate about the reasons for higher infection risk in peripheral nerve blocks, but one might be location,” commented Schulz-StÜbner, the medical director of the German Consulting Center for Infection Prevention and Control, in Freiburg. “For example, maximal barrier precautions might not be implemented for peripheral catheters in the way they are for neuraxial catheters.”
Overall, Schulz-StÜbner added, the study supports the notion that consequent use of current infection control practices is useful and sufficient.
“Given the large patient numbers required to provide evidence for additional techniques like chlorhexidine-impregnated dressings, those might be reserved for catheters with expected longer duration based on individual risk assessment,” he noted.
—Michael Vlessides
Schulz-StÜbner and Selvamani reported no relevant financial disclosures.
