Wearing a Surgical Vest with a Sterile Surgical Helmet System Decreases Contamination of the Surgical Field.

BACKGROUND: Sterile surgical helmet systems (SSHS) are frequently utilized in total knee arthroplasty procedures to protect the surgeon while maintaining a comfortable working environment. However, common helmet systems pressurize the space between the surgical gown and the surgeon's skin. In gowns with a back seam, this may allow contaminated skin particles to escape into the surgical field. By measuring bacterial colony-forming units (CFU), this study sought to determine if occlusion of the open back seam reduced the risk of potential contamination.

METHODS: First, qualitative analysis depicting airflow variations between gown configurations was performed using the Schlieren Spherical Mirror imaging system. Each gown configuration consisted of a sterile surgical helmet and one of three gown configurations: 1.) A standard gown with rear-tied closure 2.) A standard gown with a surgical vest 3.) A zippered Toga-style gown. Next, a surgeon then performed simulated surgical activities for 60 minutes within a 1.4 vm3 isolation chamber with work surfaces and controllable filtered air exchanges. During each procedure, contaminated particles were collected on sets of agar settle plates positioned directly behind the surgeon. Upon completion, the agar plates were incubated in a biolab, and the number of bacterial and fungal colony forming units (CFUs) was counted. The experimental procedure was repeated 12 times for each gown configuration, with sterilization of the chamber between runs. Contamination rates were expressed as CFUs/m2 /hr.

RESULTS: The mean contamination rate measured with the standard gown was 331.7 ± 52.0 CFU/m2 /hr. After the addition of a surgical vest, this rate decreased by 45% to 182.2 ± 30.8 CFU/m2 /hr (P = 0.02). Similarly, with the Toga-style gown, contamination rates dropped by 49% to 170.5 ± 41.9 CFU/m2 /hr (P = 0.01).

CONCLUSION: When used in conjunction with surgical helmet systems, conventional surgical gowns do not prevent potential contamination of the surgical field. We recommend that staff within the surgical field cover the back seam of standard gowns with a vest or don a zippered Toga-style gown.