Sources of contamination in the operating room: A fluorescent particle powder study

C-arm contamination of the surgical field: Can contamination be reduced with an intervening drape?

INTRODUCTION

Contamination of the surgical field by the C-arm in orthopaedic procedures is a significant potential source for surgical site infections. The purpose of this study was to explore the utility of a split sheet to aid in prevention of secondary contamination from the C-arm on the C-arm side of the operative field.

METHODS

A C-arm and a surgical table were draped by standard techniques. The surgical table was split in thirds: the surgeon's side, the C-arm side of the operative field, and the middle for contamination analysis. Fluorescent powder was used to simulate a contaminant and placed on the C-arm, floor and lower portions of drapes. The C-arm was cycled between PA and Lateral positions. Powder transfer to the field was visualized with a camera under uniform UV light. Photographs were taken to measure fluorescent pixels prior to cycling the C-arm and at 5, 10 and 15 cycles. This protocol was repeated using a split sheet (U-drape) to isolate the C-arm below the operative field. Image J was utilized to calculate differences in the number of pixels brighter than the control image.

RESULTS

Using standard draping techniques, there was contamination of the surgical field with the C-arm side of the operative field having the highest level of fluorescent pixels. The number of fluorescent pixels was linearly correlated with the number of PA to Lateral cycles. At the end of 15 cycles, the average number of fluorescent pixels for the intervening draping technique was 2.9 pixels compared to the standard draping technique of 3939 pixels (p = 0.0078).

DISCUSSION

The addition of a U-drape between the C-arm and the table results in a statistically significant reduction in surgical field contamination as a result of secondary transfer from the C-arm.

LEVEL OF EVIDENCE

II.

Should we be prepping the foot? Stockinette use and drape contamination during hip arthroplasty: An experimental study

BACKGROUND

Meticulous prepping and draping of the surgical field is paramount to reduce the risk of infection. A consistent technique for draping for hip arthroplasty is not well established. One technique for preparing the operative field utilises a sterile stockinette over an unprepped foot. This study aims to assess surgical site contamination when draping for hip arthroplasty without disinfecting the foot.

METHODS

Ultraviolet (UV) fluorescent powder was used as a surrogate for microbial presence on the foot. Powder was applied to a volunteer's foot to a level where antibacterial prep would stop. The leg was then draped according to three methods; directly with stockinette only, wrapping the foot without using an adhesive seal followed by stockinette, and wrapping the foot with the adhesive seal followed by stockinette. Proximal spread of powder after draping was assessed with UV light.

RESULTS

Contamination of the sterile field was found with all draping methods. Spread was particularly noted in the groin, posterior to the thigh and distal to mid-thigh. Wrapping the foot in a small drape without the adhesive seal prior to stockinette application was associated with significantly greater contamination when compared with use of the seal (p = 0.004).

CONCLUSION

Routine formal prepping of the foot during hip arthroplasty is recommended to reduce the risk of surgical site contamination. Surgeons who select not to prep the foot should make use of a small drape with occlusive, adhesive seal prior to stockinette application and consider applying a further U drape to the hip.

Ventilation-Associated Particulate Matter Is a Potential Reservoir of Multidrug-Resistant Organisms in Health Facilities

Most healthcare-associated infections (HCAIs) develop due to the colonisation of patients and healthcare workers by multidrug-resistant organisms (MDRO). Here, we investigated whether the particulate matter from the ventilation systems (Vent-PM) of health facilities can harbour MDRO and other microbes, thereby acting as a potential reservoir of HCAIs. Dust samples collected in the ventilation grilles and adjacent air ducts underwent a detailed analysis of physicochemical properties and biodiversity. All Vent-PM samples included ultrafine PM capable of reaching the alveoli. Strikingly, >70% of Vent-PM samples were contaminated, mostly by viruses (>15%) or multidrug-resistant and biofilm-producing bacterial strains (60% and 48% of all bacteria-contaminated specimens, respectively). Total viable count at 1 m from the ventilation grilles was significantly increased after opening doors and windows, indicating an association between air flow and bacterial contamination. Both chemical and microbial compositions of Vent-PM considerably differed across surgical vs. non-surgical and intensive vs. elective care units and between health facilities located in coal and chemical districts. Reduced diversity among MDRO and increased prevalence ratio in multidrug-resistant to the total Enterococcus spp. in Vent-PM testified to the evolving antibiotic resistance. In conclusion, we suggest Vent-PM as a previously underestimated reservoir of HCAI-causing pathogens in the hospital environment.

Clinical Issues-February 2021

Moving the surgical lights over a sterile field Key words: surgical lights, light handles, sterile field contamination, surgical site infection (SSI). Transport stretchers in the OR Key words: transport stretcher, bed linens, cross-contamination, sterile field, infectious disease. Using positive-pressure ORs for patients who require airborne precautions Key words: airborne precautions, positive-pressure airflow, positive-pressure OR, anteroom. Discontinuing the use of intraoperative bacitracin irrigation Key words: bacitracin for injection, antibiotic irrigation, antimicrobial irrigation, surgical site infection (SSI).