SEPTEMBER 4, 2024
Originally published by our sister publication Anesthesiology News
SINGAPORE—New research has uncovered a disturbing association between levels of air pollution and the occurrence of perioperative complications.
The study found that exposure to elevated airborne fine particulate matter in the seven days before surgery in a cohort of surgical patients was associated with markedly increased postoperative complications in a dose-dependent manner, a finding the investigators
Originally published by our sister publication Anesthesiology News
SINGAPORE—New research has uncovered a disturbing association between levels of air pollution and the occurrence of perioperative complications.
The study found that exposure to elevated airborne fine particulate matter in the seven days before surgery in a cohort of surgical patients was associated with markedly increased postoperative complications in a dose-dependent manner, a finding the investigators said underscores the importance of studying the issue across a broader geographic area.
“In Utah, we experience frequent inversion events where warm air high in the mountain valleys traps the cold air down below and pollution builds up,” said John F. Pearson, MD, an associate professor of anesthesiology at the University of Utah School of Medicine, in Salt Lake City. “Given my background in geography and environmental science, I thought that phenomenon represented an opportunity to use our high-quality registries and determine if preoperative exposure to fine particulate matter is associated with increased postoperative complications.”
While air pollution exposure has previously been shown to be associated with adverse health effects, its impact on postoperative outcomes is not well studied, he added.
To help address this knowledge gap, Pearson and his colleagues studied data from 98,129 surgical patients presenting to the institution, all of whom resided in a geographic region known as Utah’s Wasatch Front between 2016 and 2018. The researchers then geocoded the patients’ addresses and linked them with census-level pollution estimates over the three weeks before surgery using a large-scale air quality model. Multivariate testing was used to determine the association between mean seven-day pollutant exposure and the study’s primary outcome, which was a composite of stroke, myocardial infarction, acute kidney injury and surgical site infection. Models adjusted for age, sex and the Elixhauser Comorbidity Index.
“The PM2.5 definition of fine particulate matter that we used is an EPA [Environmental Protection Agency]-regulated air pollutant, and one that usually comes from combustion sources, but can also be from soil or wildfires,” Pearson told Anesthesiology News.
In a presentation at the 18th World Congress of Anaesthesiologists (abstract AP02.05), the researchers revealed that the rate of postoperative complications increased in a dose-dependent manner with higher levels of PM2.5 exposure. Specifically, mean levels of fine particulate matter above 35 mcg/m3 were associated with complication rates approximately 28% higher compared with levels below that threshold (odds ratio, 1.28). Interestingly, this association was independent of patient comorbidities.
“Our hypothesis was that there would be an inflammatory response to air pollution which would then be worsened by the known inflammatory response to surgery, which would then increase the risk to patients in the perioperative and postoperative periods,” Pearson said. “And that’s what we ended up finding.”
While the researchers recognized that the potential effect of pollution on outcomes may seem nominal initially, population-wide effects may be more pronounced.
“When you multiply it across a population, it’s actually a lot of people that are affected because everybody’s exposed to air pollution,” he explained.
These findings, the researchers said, not only illustrate the need to study the issue in different regions and populations, but should serve as a springboard to potentially mitigate the effect of pollution on patient outcomes.
“For one thing, we need to understand who’s at highest risk because then we can develop countermeasures,” Pearson said. “I would say it’s early to start making decisions based on what we’ve found so far, but should our results be borne out in other studies, maybe patients go home and wait for better conditions, or perhaps we should utilize air filtration in their room or their house. In China, they actually showed that rescheduling cases during times of high pollution was actually beneficial and cost-effective.”
“There may be also some things that we could do around preoperative treatments or certain extra doses of medications to reduce the inflammatory response among susceptible populations,” he added. Findings such as these may also inform policy decisions in the future, he noted.
Commenting on the findings, Scarlett McNally, MB Bchir, the deputy director of the Centre for Perioperative Care, in London, said much is already known about the substantial impacts of pollution on short- and long-term health.
“Pollution is not just about asthma,” she said. “The tiny particles have a direct effect on inflammation and mean that people may have devastating outcomes from surgery. We need to make things better for patients before surgery, including encouraging them to be active and have good nutrition to counter the additional burden of pollution. We may need to consider rescheduling whole lists.”
As McNally discussed, healthcare professionals should recognize waste that causes pollution is a core responsibility.
“We should also advocate for reducing pollution and increasing sustainability,” she said. “Wear from brakes, tires and roads are a major source of PM2.5 particulates. Improvements need investment in freight and public transport, safe infrastructure and storage for active travel (cycling and walking), and disincentives to polluting industries and transport by motor vehicles.
“Individual behaviors are not enough. We should use our health focus to support governments and organizations—including our own—to reduce pollution.”
By Michael Vlessides
McNally and Pearson reported no relevant financial disclosures. The abstract won third prize as the best clinical research abstract at the meeting.
