Viral Particle Aerosolization During Tracheostomy Care Can Be Minimized

By Reuters Staff

July 29, 2021

NEW YORK (Reuters Health) - Tracheostomy care leads to significant aerosol generation, but experiments in manikins suggest covering the stoma with a heat moisture exchanger and surgical mask can lead to a significant risk reduction.

Furthermore, researchers found, use of electrocautery during swine tracheostomy procedures significantly increased dispersion of aerosolized particles, compared to use of cold instrumentation.

In an online paper in JAMA Otolaryngology-Head & Neck Surgery, Dr. Alexander T. Hillel of Johns Hopkins Medical Institution, Baltimore, Maryland, and colleagues acknowledge that masks have been at the forefront of primary public health efforts against SARS-CoV-2 transmission but "there is limited evidence-based guidance for mask use in patients with a tracheostomy."

To investigate further, the researchers used an optical particle counter to measure concentration and size distribution of respirable particles with a diameter smaller than 4 micrometers during simulated tracheostomy conditions using a manikin, including cough, airway nebulization, and open suctioning. Readings were normalized via 2-minute background baseline checks in a simulated operating room prior to simulated patient care.

Compared with an unmasked control, particle concentration was decreased by 73.8%, with a cotton mask, 79.5% with a polyester gaiter and 82.8% with a humidification mask. A surgical mask alone reduced particle concentration by 89.9% similar to the 91.0% seen with a heat moisture exchanger (HME). Simultaneous use of the surgical mask and HME was associated with a reduction in particle concentration of 97.9%.

Aerosol generation was also evaluated during swine tracheostomy surgery to compare electrocautery to cold instrumentation, to identify high aerosol generating periods, and to assess concentrations relative to the positions of the surgeon, anesthesiologist, and operating room staff.

Compared with using cold instrumentation, swine tracheostomy procedures performed with electrocautery increased total aerosolized particles by 1500 particles/m3 per 5-second interval. "Avoidance of electrocautery," say the investigators, "represents a technique to limit aerosol exposure during tracheostomy or any surgery involving potentially infectious tissue."

The researchers conclude that "the combination of an HME and surgical mask over the tracheostomy reduced aerosol concentration to the greatest degree" and although the "study was prompted by the novel SARS-CoV-2, these results are applicable to emerging and future aerosol transmissible diseases to prevent nosocomial viral spread during tracheostomy care."

Dr. Hillel did not respond to requests for comments.

SOURCE: JAMA Otolaryngology-Head & Neck Surgery, online July 22, 2021.