20 February 2018

Surgical Headgear Study Published in Journal of American College of Surgeons

This past year, AAF's Clean Air Innovation and Research Centre played a key role in a study developed by the Indiana University School of Medicine in Indianapolis and funded by the American College of Surgeons and the American Society of Anesthesiologists.


This study, titled “Hats Off: A Study of Different Operating Room Headgear Assessed by Environmental Quality Indicators,” was published in the November 2017 issue of the Journal of the American College of Surgeons, and will be presented at the Indiana University School of Medicine (IUSM) in March, 2018.


Dr. Troy Markel of IUSM and his colleagues knew that hospital-acquired infections (HAIs) cost hospital systems a great deal each year. In fact, HAIs cost nearly $10 billion annually, with surgical site infections comprising nearly one third of that cost. Clearly anything that could reduce surgical site infections, including controlling airborne contamination and reducing microbial shed from personnel in the operating room, is of vital importance.


Surgical Headgear Study Published in Journal of American College of Surgeons 


Surgical attire, such as sterile gloves and impervious surgical gowns, have been shown to reduce surgical site infections, but the effectiveness of various types of surgical headgear to reduce infections has been called into question.


Surgical skull caps expose the hair around the nape of the neck and the sides of the head, in addition to the ears. A bouffant style hat has been deemed superior by some experts because these hats can be worn over the ears and hair, which are known sources of bacterial contaminants. Dr. Markel and his colleagues therefore decided to design this study to test both bouffant and skullcap types of surgical headgear, in order to gauge both types’ effectiveness. They hypothesized that there would be no difference between the two types of headgear.


However, Indiana University did not have a facility designed for these types of tests. So the IUSM group came to the Clean Air Centre with a question – could the Centre help them with the study, both by suggesting ways to test the headgear in terms of airborne contaminants and microbial shed, and conducting these tests themselves?


Clean Air Center, performing air filter testing and air filtration innovation in Jeffersonville, Indiana 



The Centre agreed, with Dr. Rahul Bharadwaj leading the design of the tests, as well as the execution. These tests were conducted May through June, 2017, after mock surgical sessions had been conducted in dynamic operating room environments.


Airborne particulate and microbial contaminants were sampled, and hat fabric was tested for permeability, particle transmission, and pore sizes.


The results were that no significant differences were observed between bouffant and skull caps with regard to particles or actively sampled microbes. The bouffant hats were actually worse in terms of microbial shed, maximum pore size, and permeability.


This study is significant because surgery headgear is rarely tested for particle penetration or pore size. There are no requirements currently in place to test this type of media for these qualities.


Going forward, there is a grant under review to study cloth hats that are freshly laundered, compared to cloth hats that have not been laundered for a set number of weeks. This grant would also be used to study the effect that beard covers would have on airborne contaminants.


Dr. Markel commented, “This paper has definitely made an impact on the field and may lead to protocol changes regarding material designed for surgical applications.” Dr. Bharadwaj added, “We’re glad we discovered something that could potentially have an impact on infections acquired while in hospital.”