Characterization of Aerosols Produced during Surgical Procedures in Hospitals

In orthopedic surgical procedures, surgical power tools, such as electrocautery, bone saws, reamers, and drills, are commonly used. In laboratory experiments using these tools, it has been demonstrated that inhalable aerosols can be produced. In order to assess the potential exposure of health care workers to these aerosols during orthopedic surgery, it is necessary to characterize the aerosols. In this study, Marple personal cascade impactors (MPCI) and a Quartz Crystal Microbalance (QCM) were used to measure the size distribution of the aerosols, and filter samples were collected to estimate the aerosol mass concentration. A Chemstrip 9 analysis to measure hemoglobin was applied to samples collected at each stage of the MPCIs as well as QCM and filter samples. During ten surgical procedures, including total hip replacements, total knee replacements, a back vertebral fusion, and a hip reconstruction, aerosols were sampled. Aerosol mass concentrations and size distributions varied widely from procedure to procedure and from time to time. Analysis of samples from the MPCIs worn by the surgeons indicated that measurable amounts of aerosols containing hemoglobin-associated particles as indicated by the Chemstrip 9 response were detected for all surgical procedures studied. Comparison between knee operations, in which a tourniquet was applied to reduce or stop the blood flow at the surgical site, and hip replacement operations suggested that irrigation / suction, which was used in all surgical procedures, was one of a key contributor to producing blood-associated aerosols. QCM data indicated that the aerosol mass concentration was highest when the surgical site was opened with the use of a scalpel, electrocautery, and irrigation / suction. Area filter samples and MPCI samples from personnel other than surgeons occasionally showed trace amounts of hemoglobin-associated particles; this was probably due to splashing during the irrigation / suction procedure. Clean-up of the room after surgery did not appear to re-suspend any blood-associated aerosols. In summary, low concentrations of aerosol particles were produced during orthopedic surgical procedures. The concentration and size distribution of these particles depended on the procedure being performed. Some of these particles contained hemoglobin. However, the existing literature does not provide evidence that the blood-borne pathogens, such as human immunodeficiency virus or hepatitis B virus, have been transferred by inhaling aerosols. Further studies on the amount and viability of pathogens associated with these blood-associated aerosols are required to ascertain the significance of these measurements.