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Leonard Schultz, Nascent SurgicalHigh risk patient and protocol factors that predispose to the development of post-operative wound infections have been extensively researched. Government sponsored initiatives (SIP and SCIP), published in “Specifications Manual for National Inpatient Quality Measures”, concluded that compliance with standards of care processes for surgical procedures would lead to improved outcome results. The jury is still out on any beneficial results of these projects.

Certainly, such efforts are worthwhile attempts to solve a serious problem since current data indicates some 300,000 surgical site infections (SSI’s) occur yearly in the United States with an increase in length of stay by seven to 10 days at an annual cost of one billion dollars. The resultant mortality rate is 5 percent with three-quarters of those deaths directly attributable to the infection itself.

Perhaps an understanding of infections’ biological cause(s) and support for innovative ways to control it/them should now take precedence. “Aerobiology” is the study of the processes involved in the movement of microorganisms in the ambient air from one location to another including the aerosolized transmission of disease which occurs through both airborne and droplet means.”  It is this transfer of potentially infective material released within aerosols and droplets during surgery that could account for persistent SSI rates despite strict adherence to existing protocols. In the case of elecrosurgery, it is established that viable bacteria are released from the patient and are present in the bioaerosols which are commonly referred to as surgical smoke. The likely result of its dispersal is the contamination of sterile instruments on the back table and the Mayo stand which are used throughout the surgery, thus serving as the continuing source of wound contamination with the patient’s own bacteria. Coincidentally, in addition to aerosols, bacteria could directly seed the wound in the form of droplet transmission which covers the area of the surgical field.

These two methods of transmission were recently reported upon in the July issue of the AORN Journal.  A sterile “glove box” environment was used to study the transmission process. Sterile meat was impregnated with Serratia marsescens which was then cauterized with blended electric current. Plume was released and colony counts were determined with Petri dishes filled with sterile agar media placed at five locations. Extensive colonies were cultured from the most distant plate while significant colonies occurred on four plates placed at quadrants adjacent to the contaminated meat to simulate a surgical wound. In effect, both aerosol (far) and droplet (near) transmission were examined.

The second part of the experiment showed the promise that effective capture of a bioaerosol with adequate suction could have on reducing that rate of SSI’s. Use of a previously documented, highly effective capture device (99.5 percent capture efficiency) paired with an evacuator that generated 35 cfm of airflow resulted in:

  • Absence of aerosol spread of bacteria.  
  • Significant reduction in droplet transmission onto two of the four adjacent Petri dishes closest to the capture device.

OSHA has long recognized the potential for aerosol transmission of disease.  They have also enacted legislation that mandates protection against contact contamination from potentially infective blood but not from inhalation of the same potentially infected body fluid present in bioaerosol form (smoke). To this, we now add that bioaerosol most likely also plays a significant role in post-operative wound infection.

This aerosol and droplet transmission method of wound contamination has remained below the radar long enough and needs to be addressed, especially now that technology exists that allows for its significant diminution and/or elimination. Clinical investigation that emphasizes aerosol capture as an important infection control method is anticipated as we seek additional ways to improve patient outcomes.

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