Minimally Required Personal Protective Equipment during Local Anesthesia Surgery in COVID-19: A Simulation Study

Abstract

In the era of the coronavirus disease 2019 (COVID-19) pandemic, surgeons and medical staff are often at a high risk of infection in the operating room, especially when the patient is spontaneously breathing. In this study, we examined the minimum requirements for personal protective equipment with double surgical masks to potentially reduce unnecessary waste of supplies.

Methods: Two mannequins were each connected to a test lung machine simulating a surgeon and patient with spontaneous breathing. An aerosol generator containing severe acute respiratory syndrome coronavirus 2 virion particle substitutes was connected to the patient mannequin. The sampling points for the target molecules were set at different distances from the patient mannequin and sent for multiplex quantitative polymerase chain reaction analysis. Three clinical scenarios were designed, which differed in terms of the operating room pressure and whether a fabric curtain barrier was installed between the mannequins.

Results: Analysis of the multiplex quantitative polymerase chain reaction results showed that the cycle threshold (Ct) value of the target molecule increased as the distance from the aerosol source increased. In the negative-pressure operating room, the Ct values were significantly increased at all sample points compared with the normal pressure room setting. The Ct value sampled at the surgeon mannequin wearing double face masks was significantly increased when a cloth curtain barrier was set up between the two mannequins.

Conclusion: Double surgical masks provide elementary surgeon protection against COVID-19 in a negative pressure operating room, with a physical barrier in place between the surgeon and patient who is spontaneously breathing during local anesthesia or sedated surgery.

Fig. 1.

Design setup. Mannequin S represents the surgeon and mannequin P represents the patient, each is connected to an individual test lung. One of the two chambers of the test lung is connected to a driving ventilator. The nebulizer containing the target molecules is connected to mannequin P.

Fig. 2.

Design set up with actual images. A, Mannequin P as the patient. B, Mannequins S as the surgeon. C, Cloth curtain between the two mannequins with view from the patient’s cranial side. D, Cloth curtain between the two mannequins with view from the surgeon’s side. E, Operation scene in the real world.

Fig. 3.

Sampling sites. (1) 0.25-m cephalad to the aerosol outlet, (2) 0.25-m caudal to the aerosol outlet, (3) 0.5-m caudal to the aerosol outlet, (4) 1.0-m caudal to the aerosol outlet, (5) 1.5-m caudal to the aerosol outlet, (6) outer surface of the surgeon’s double mask, (7) inner surface of the surgeon’s double mask, and (8) inner surface of the aerosol outlet tubing.

Fig. 4.

Analysis of the multiplex qPCR results for all scenarios.